Add helpers for performing fixed point optimization#1176

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Merged
copybara-service merged 1 commit into from
Aug 10, 2026
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Add helpers for performing fixed point optimization #1176

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221 changes: 209 additions & 12 deletions optimizer/src/main/java/dev/cel/optimizer/AstMutator.java
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Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -18,17 +18,19 @@
import static java.lang.Math.max;
import static java.util.stream.Collectors.toCollection;

import com.google.auto.value.AutoOneOf;
import com.google.auto.value.AutoValue;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.HashBasedTable;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Streams;
import com.google.common.collect.Table;
import com.google.errorprone.annotations.Immutable;
import dev.cel.common.CelAbstractSyntaxTree;
import dev.cel.common.CelMutableAst;
import dev.cel.common.CelMutableSource;
import dev.cel.common.ast.CelExpr.ExprKind.Kind;
import dev.cel.common.ast.CelExpr.ExprKind;
import dev.cel.common.ast.CelExprIdGeneratorFactory;
import dev.cel.common.ast.CelExprIdGeneratorFactory.ExprIdGenerator;
import dev.cel.common.ast.CelExprIdGeneratorFactory.StableIdGenerator;
Expand All@@ -49,6 +51,7 @@
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Collectors;

Expand DownExpand Up@@ -213,7 +216,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
Predicate<CelNavigableMutableExpr> comprehensionIdentifierPredicate = x -> true;
comprehensionIdentifierPredicate =
comprehensionIdentifierPredicate
.and(node -> node.getKind().equals(Kind.COMPREHENSION))
.and(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
.and(node -> !node.expr().comprehension().iterVar().startsWith(newIterVarPrefix + ":"))
.and(node -> !node.expr().comprehension().accuVar().startsWith(newAccuVarPrefix + ":"))
.and(
Expand All@@ -235,7 +238,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
String result = node.expr().comprehension().result().ident().name();
return CelNavigableMutableExpr.fromExpr(node.expr().comprehension().loopStep())
.allNodes()
.filter(subNode -> subNode.getKind().equals(Kind.IDENT))
.filter(subNode -> subNode.getKind().equals(ExprKind.Kind.IDENT))
.map(subNode -> subNode.expr().ident())
.anyMatch(
ident ->
Expand All@@ -259,7 +262,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
.allNodes()
.filter(
loopStepNode ->
loopStepNode.getKind().equals(Kind.IDENT)
loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
&& loopStepNode.expr().ident().name().equals(iterVar))
.map(CelNavigableMutableExpr::id)
.findAny();
Expand All@@ -269,7 +272,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
.filter(
loopStepNode ->
!iterVar2.isEmpty()
&& loopStepNode.getKind().equals(Kind.IDENT)
&& loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
&& loopStepNode.expr().ident().name().equals(iterVar2))
.map(CelNavigableMutableExpr::id)
.findAny();
Expand DownExpand Up@@ -406,13 +409,13 @@ private static MangledComprehensionName getMangledComprehensionName(
private static int countComprehensionNestingLevel(CelNavigableMutableExpr comprehensionExpr) {
return comprehensionExpr
.descendants()
.filter(node -> node.getKind().equals(Kind.COMPREHENSION))
.filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
.mapToInt(
node -> {
int nestedLevel = 1;
CelNavigableMutableExpr maybeParent = node.parent().orElse(null);
while (maybeParent != null && maybeParent.id() != comprehensionExpr.id()) {
if (maybeParent.getKind().equals(Kind.COMPREHENSION)) {
if (maybeParent.getKind().equals(ExprKind.Kind.COMPREHENSION)) {
nestedLevel++;
}
maybeParent = maybeParent.parent().orElse(null);
Expand DownExpand Up@@ -552,6 +555,151 @@ public CelMutableAst replaceSubtree(
return CelMutableAst.of(mutatedRoot, newAstSource);
}

/**
* Replaces a subtree in the given AST with the specified {@link SubtreeReplacement}.
*
* <p>This operation is intended for AST optimization purposes.
*
* <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
* additionally verify that the resulting AST is semantically valid.
*
* <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
* between the nodes. The renumbering occurs even if the subtree was not replaced.
*
* @param ast Original AST to mutate.
* @param replacement Subtree replacement containing the target node ID and the new expression or
* AST.
*/
public CelMutableAst replaceSubtree(CelMutableAst ast, SubtreeReplacement replacement) {
Preconditions.checkNotNull(ast);
Preconditions.checkNotNull(replacement);
switch (replacement.replacement().kind()) {
case EXPR:
return replaceSubtree(ast, replacement.replacement().expr(), replacement.exprIdToReplace());
case AST:
return replaceSubtree(ast, replacement.replacement().ast(), replacement.exprIdToReplace());
}
throw new IllegalArgumentException(
"Unsupported replacement kind: " + replacement.replacement().kind());
}

/**
* Repeatedly applies AST mutations using the provided AST-level rewriter until no further
* replacements match (fixed point reached) or the mutator's iteration limit is exhausted.
*
* <p>Per iteration pass, the AST is traversed to find and perform at most one matching subtree
* substitution before restarting traversal on the newly mutated AST.
*
* <p>This operation is intended for AST optimization purposes.
*
* <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
* additionally verify that the resulting AST is semantically valid.
*
* <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
* between the nodes.
*
* @param ast Initial mutable AST to mutate.
* @param astRewriter Function returning a {@link SubtreeReplacement} or {@code Optional.empty()}
* when no further rewrites are possible.
* @return Mutated {@link CelMutableAst} at fixed point.
* @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
*/
public CelMutableAst mutateUntilFixedPoint(
CelMutableAst ast,
Function<CelNavigableMutableAst, Optional<SubtreeReplacement>> astRewriter) {
Preconditions.checkNotNull(ast);
Preconditions.checkNotNull(astRewriter);
CelMutableAst mutableAst = ast;
for (long i = 0; i < iterationLimit; i++) {
CelNavigableMutableAst navAst = CelNavigableMutableAst.fromAst(mutableAst);
Optional<SubtreeReplacement> replacement = astRewriter.apply(navAst);
if (!replacement.isPresent()) {
return mutableAst;
}
mutableAst = replaceSubtree(mutableAst, replacement.get());
}
throw new IllegalStateException("Max iteration count reached.");
}

/**
* Traverses nodes using the specified {@link TraversalOrder} and repeatedly rewrites matching
* subtrees until a fixed point is reached.
*
* <p>Per iteration pass, the AST is walked in the given order to find and perform the first
* matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
* match or the mutator's iteration limit is exhausted.
*
* <p>This operation is intended for AST optimization purposes.
*
* <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
* additionally verify that the resulting AST is semantically valid.
*
* <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
* between the nodes.
*
* @param ast Initial mutable AST to mutate.
* @param traversalOrder Order in which nodes are visited per iteration pass.
* @param nodeRewriter Function returning a {@link SubtreeReplacement} or {@code
* Optional.empty()}.
* @return Mutated {@link CelMutableAst} at fixed point.
* @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
*/
public CelMutableAst mutateUntilFixedPoint(
CelMutableAst ast,
TraversalOrder traversalOrder,
Function<CelNavigableMutableExpr, Optional<SubtreeReplacement>> nodeRewriter) {
Preconditions.checkNotNull(traversalOrder);
Preconditions.checkNotNull(nodeRewriter);
return mutateUntilFixedPoint(
ast,
navAst ->
navAst
.getRoot()
.allNodes(traversalOrder)
.flatMap(node -> Streams.stream(nodeRewriter.apply(node)))
.findFirst());
}

/**
* Traverses nodes using the specified {@link TraversalOrder}, applies the node matcher, and
* substitutes matching nodes with the returned replacement expression (targeting {@code
* node.id()}).
*
* <p>Per iteration pass, the AST is walked in the given order to find and perform the first
* matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
* match or the mutator's iteration limit is exhausted.
*
* <p>This operation is intended for AST optimization purposes.
*
* <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
* additionally verify that the resulting AST is semantically valid.
*
* <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
* between the nodes.
*
* @param ast Initial mutable AST to mutate.
* @param traversalOrder Order in which nodes are visited per iteration pass.
* @param nodeMatcher Predicate to filter candidate nodes.
* @param nodeRewriter Function producing the new {@link CelMutableExpr} for matched nodes.
* @return Mutated {@link CelMutableAst} at fixed point.
* @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
*/
public CelMutableAst mutateUntilFixedPoint(
CelMutableAst ast,
TraversalOrder traversalOrder,
Predicate<CelNavigableMutableExpr> nodeMatcher,
Function<CelNavigableMutableExpr, Optional<CelMutableExpr>> nodeRewriter) {
Preconditions.checkNotNull(nodeMatcher);
Preconditions.checkNotNull(nodeRewriter);
return mutateUntilFixedPoint(
ast,
traversalOrder,
node ->
nodeMatcher.test(node)
? nodeRewriter.apply(node).map(newExpr -> SubtreeReplacement.of(node.id(), newExpr))
: Optional.empty());
}

private CelMutableExpr mangleIdentsInComprehensionExpr(
CelMutableExpr root,
CelMutableExpr comprehensionExpr,
Expand DownExpand Up@@ -590,7 +738,7 @@ private void replaceIdentName(
.map(CelNavigableMutableExpr::expr)
.filter(
node ->
node.getKind().equals(Kind.IDENT)
node.getKind().equals(ExprKind.Kind.IDENT)
&& node.ident().name().equals(originalIdentName))
.findAny()
.orElse(null);
Expand DownExpand Up@@ -776,7 +924,7 @@ private CelMutableSource normalizeMacroSource(
long replacedId = idGenerator.generate(exprIdToReplace);
boolean isListExprBeingReplaced =
allExprs.containsKey(replacedId)
&& allExprs.get(replacedId).getKind().equals(Kind.LIST);
&& allExprs.get(replacedId).getKind().equals(ExprKind.Kind.LIST);
if (isListExprBeingReplaced) {
unwrapListArgumentsInMacroCallExpr(
allExprs.get(callId).comprehension(), newMacroCallExpr);
Expand All@@ -791,7 +939,7 @@ private CelMutableSource normalizeMacroSource(
CelMutableExpr macroCallExpr = macroCall.getValue();
CelNavigableMutableExpr.fromExpr(macroCallExpr)
.allNodes()
.filter(node -> node.getKind().equals(Kind.COMPREHENSION))
.filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
.map(CelNavigableMutableExpr::expr)
.forEach(
node -> {
Expand All@@ -808,7 +956,7 @@ private CelMutableSource normalizeMacroSource(
// This can occur from pulling out a nested comprehension into a separate cel.block index
CelNavigableMutableExpr.fromExpr(macroCallExpr)
.allNodes()
.filter(node -> node.getKind().equals(Kind.NOT_SET))
.filter(node -> node.getKind().equals(ExprKind.Kind.NOT_SET))
.map(CelNavigableMutableExpr::id)
.filter(id -> !allExprs.containsKey(id))
.forEach(
Expand DownExpand Up@@ -840,7 +988,7 @@ private CelMutableSource normalizeMacroSource(
private static void unwrapListArgumentsInMacroCallExpr(
CelMutableComprehension comprehension, CelMutableExpr newMacroCallExpr) {
CelMutableExpr accuInit = comprehension.accuInit();
if (!accuInit.getKind().equals(Kind.LIST) || !accuInit.list().elements().isEmpty()) {
if (!accuInit.getKind().equals(ExprKind.Kind.LIST) || !accuInit.list().elements().isEmpty()) {
// Does not contain an extraneous list.
return;
}
Expand DownExpand Up@@ -983,4 +1131,53 @@ private static MangledComprehensionName of(
iterVarName, iterVar2Name, resultName);
}
}

/**
* Represents a planned subtree replacement containing the target node ID to replace and either a
* {@link CelMutableExpr} or {@link CelMutableAst}.
*/
@AutoValue
public abstract static class SubtreeReplacement {

public abstract long exprIdToReplace();

public abstract Replacement replacement();

public static SubtreeReplacement of(long exprIdToReplace, CelMutableExpr replacementExpr) {
return new AutoValue_AstMutator_SubtreeReplacement(
exprIdToReplace, Replacement.ofExpr(replacementExpr));
}

public static SubtreeReplacement of(long exprIdToReplace, CelMutableAst replacementAst) {
return new AutoValue_AstMutator_SubtreeReplacement(
exprIdToReplace, Replacement.ofAst(replacementAst));
}

/** Discriminated union of either a {@link CelMutableExpr} or a {@link CelMutableAst}. */
@AutoOneOf(Replacement.Kind.class)
public abstract static class Replacement {

public abstract CelMutableExpr expr();

public abstract CelMutableAst ast();

public abstract Replacement.Kind kind();

public static Replacement ofExpr(CelMutableExpr expr) {
return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.expr(
Preconditions.checkNotNull(expr));
}

public static Replacement ofAst(CelMutableAst ast) {
return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.ast(
Preconditions.checkNotNull(ast));
}

/** Kind of {@link Replacement}. */
public enum Kind {
EXPR,
AST
}
}
}
}
1 change: 1 addition & 0 deletions optimizer/src/main/java/dev/cel/optimizer/optimizers/BUILD.bazel
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -96,6 +96,7 @@ java_library(
"//common:operator",
"//common/ast",
"//common/ast:mutable_expr",
"//common/navigation:common",
"//common/navigation:expr_util",
"//common/navigation:mutable_navigation",
"//common/types",
Expand Down
Loading
Loading
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

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Add helpers for performing fixed point optimization#1176

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 Merged

copybara-service
merged 1 commit into

from

Aug 10, 2026
 Merged


Add helpers for performing fixed point optimization
#1176
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221 changes: 209 additions & 12 deletions
optimizer/src/main/java/dev/cel/optimizer/AstMutator.java

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -18,17 +18,19 @@
import static java.lang.Math.max;
import static java.util.stream.Collectors.toCollection;

import com.google.auto.value.AutoOneOf;
import com.google.auto.value.AutoValue;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.HashBasedTable;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Streams;
import com.google.common.collect.Table;
import com.google.errorprone.annotations.Immutable;
import dev.cel.common.CelAbstractSyntaxTree;
import dev.cel.common.CelMutableAst;
import dev.cel.common.CelMutableSource;
import dev.cel.common.ast.CelExpr.ExprKind.Kind;
import dev.cel.common.ast.CelExpr.ExprKind;
import dev.cel.common.ast.CelExprIdGeneratorFactory;
import dev.cel.common.ast.CelExprIdGeneratorFactory.ExprIdGenerator;
import dev.cel.common.ast.CelExprIdGeneratorFactory.StableIdGenerator;
Expand All@@ -49,6 +51,7 @@
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Collectors;

Expand DownExpand Up@@ -213,7 +216,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 Predicate<CelNavigableMutableExpr> comprehensionIdentifierPredicate = x -> true;
 comprehensionIdentifierPredicate =
 comprehensionIdentifierPredicate
 .and(node -> node.getKind().equals(Kind.COMPREHENSION))
 .and(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .and(node -> !node.expr().comprehension().iterVar().startsWith(newIterVarPrefix + ":"))
 .and(node -> !node.expr().comprehension().accuVar().startsWith(newAccuVarPrefix + ":"))
 .and(
Expand All@@ -235,7 +238,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 String result = node.expr().comprehension().result().ident().name();
 return CelNavigableMutableExpr.fromExpr(node.expr().comprehension().loopStep())
 .allNodes()
 .filter(subNode -> subNode.getKind().equals(Kind.IDENT))
 .filter(subNode -> subNode.getKind().equals(ExprKind.Kind.IDENT))
 .map(subNode -> subNode.expr().ident())
 .anyMatch(
 ident ->
Expand All@@ -259,7 +262,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 .allNodes()
 .filter(
 loopStepNode ->
 loopStepNode.getKind().equals(Kind.IDENT)
 loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
 && loopStepNode.expr().ident().name().equals(iterVar))
 .map(CelNavigableMutableExpr::id)
 .findAny();
Expand All@@ -269,7 +272,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 .filter(
 loopStepNode ->
 !iterVar2.isEmpty()
 && loopStepNode.getKind().equals(Kind.IDENT)
 && loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
 && loopStepNode.expr().ident().name().equals(iterVar2))
 .map(CelNavigableMutableExpr::id)
 .findAny();
Expand DownExpand Up@@ -406,13 +409,13 @@ private static MangledComprehensionName getMangledComprehensionName(
 private static int countComprehensionNestingLevel(CelNavigableMutableExpr comprehensionExpr) {
 return comprehensionExpr
 .descendants()
 .filter(node -> node.getKind().equals(Kind.COMPREHENSION))
 .filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .mapToInt(
 node -> {
 int nestedLevel = 1;
 CelNavigableMutableExpr maybeParent = node.parent().orElse(null);
 while (maybeParent != null && maybeParent.id() != comprehensionExpr.id()) {
 if (maybeParent.getKind().equals(Kind.COMPREHENSION)) {
 if (maybeParent.getKind().equals(ExprKind.Kind.COMPREHENSION)) {
 nestedLevel++;
 }
 maybeParent = maybeParent.parent().orElse(null);
Expand DownExpand Up@@ -552,6 +555,151 @@ public CelMutableAst replaceSubtree(
 return CelMutableAst.of(mutatedRoot, newAstSource);
 }

 /**
 * Replaces a subtree in the given AST with the specified {@link SubtreeReplacement}.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes. The renumbering occurs even if the subtree was not replaced.
 *
 * @param ast Original AST to mutate.
 * @param replacement Subtree replacement containing the target node ID and the new expression or
 * AST.
 */
 public CelMutableAst replaceSubtree(CelMutableAst ast, SubtreeReplacement replacement) {
 Preconditions.checkNotNull(ast);
 Preconditions.checkNotNull(replacement);
 switch (replacement.replacement().kind()) {
 case EXPR:
 return replaceSubtree(ast, replacement.replacement().expr(), replacement.exprIdToReplace());
 case AST:
 return replaceSubtree(ast, replacement.replacement().ast(), replacement.exprIdToReplace());
 }
 throw new IllegalArgumentException(
 "Unsupported replacement kind: " + replacement.replacement().kind());
 }

 /**
 * Repeatedly applies AST mutations using the provided AST-level rewriter until no further
 * replacements match (fixed point reached) or the mutator's iteration limit is exhausted.
 *
 * <p>Per iteration pass, the AST is traversed to find and perform at most one matching subtree
 * substitution before restarting traversal on the newly mutated AST.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param astRewriter Function returning a {@link SubtreeReplacement} or {@code Optional.empty()}
 * when no further rewrites are possible.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 Function<CelNavigableMutableAst, Optional<SubtreeReplacement>> astRewriter) {
 Preconditions.checkNotNull(ast);
 Preconditions.checkNotNull(astRewriter);
 CelMutableAst mutableAst = ast;
 for (long i = 0; i < iterationLimit; i++) {
 CelNavigableMutableAst navAst = CelNavigableMutableAst.fromAst(mutableAst);
 Optional<SubtreeReplacement> replacement = astRewriter.apply(navAst);
 if (!replacement.isPresent()) {
 return mutableAst;
 }
 mutableAst = replaceSubtree(mutableAst, replacement.get());
 }
 throw new IllegalStateException("Max iteration count reached.");
 }

 /**
 * Traverses nodes using the specified {@link TraversalOrder} and repeatedly rewrites matching
 * subtrees until a fixed point is reached.
 *
 * <p>Per iteration pass, the AST is walked in the given order to find and perform the first
 * matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
 * match or the mutator's iteration limit is exhausted.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param traversalOrder Order in which nodes are visited per iteration pass.
 * @param nodeRewriter Function returning a {@link SubtreeReplacement} or {@code
 * Optional.empty()}.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 TraversalOrder traversalOrder,
 Function<CelNavigableMutableExpr, Optional<SubtreeReplacement>> nodeRewriter) {
 Preconditions.checkNotNull(traversalOrder);
 Preconditions.checkNotNull(nodeRewriter);
 return mutateUntilFixedPoint(
 ast,
 navAst ->
 navAst
 .getRoot()
 .allNodes(traversalOrder)
 .flatMap(node -> Streams.stream(nodeRewriter.apply(node)))
 .findFirst());
 }

 /**
 * Traverses nodes using the specified {@link TraversalOrder}, applies the node matcher, and
 * substitutes matching nodes with the returned replacement expression (targeting {@code
 * node.id()}).
 *
 * <p>Per iteration pass, the AST is walked in the given order to find and perform the first
 * matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
 * match or the mutator's iteration limit is exhausted.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param traversalOrder Order in which nodes are visited per iteration pass.
 * @param nodeMatcher Predicate to filter candidate nodes.
 * @param nodeRewriter Function producing the new {@link CelMutableExpr} for matched nodes.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 TraversalOrder traversalOrder,
 Predicate<CelNavigableMutableExpr> nodeMatcher,
 Function<CelNavigableMutableExpr, Optional<CelMutableExpr>> nodeRewriter) {
 Preconditions.checkNotNull(nodeMatcher);
 Preconditions.checkNotNull(nodeRewriter);
 return mutateUntilFixedPoint(
 ast,
 traversalOrder,
 node ->
 nodeMatcher.test(node)
 ? nodeRewriter.apply(node).map(newExpr -> SubtreeReplacement.of(node.id(), newExpr))
 : Optional.empty());
 }

 private CelMutableExpr mangleIdentsInComprehensionExpr(
 CelMutableExpr root,
 CelMutableExpr comprehensionExpr,
Expand DownExpand Up@@ -590,7 +738,7 @@ private void replaceIdentName(
 .map(CelNavigableMutableExpr::expr)
 .filter(
 node ->
 node.getKind().equals(Kind.IDENT)
 node.getKind().equals(ExprKind.Kind.IDENT)
 && node.ident().name().equals(originalIdentName))
 .findAny()
 .orElse(null);
Expand DownExpand Up@@ -776,7 +924,7 @@ private CelMutableSource normalizeMacroSource(
 long replacedId = idGenerator.generate(exprIdToReplace);
 boolean isListExprBeingReplaced =
 allExprs.containsKey(replacedId)
 && allExprs.get(replacedId).getKind().equals(Kind.LIST);
 && allExprs.get(replacedId).getKind().equals(ExprKind.Kind.LIST);
 if (isListExprBeingReplaced) {
 unwrapListArgumentsInMacroCallExpr(
 allExprs.get(callId).comprehension(), newMacroCallExpr);
Expand All@@ -791,7 +939,7 @@ private CelMutableSource normalizeMacroSource(
 CelMutableExpr macroCallExpr = macroCall.getValue();
 CelNavigableMutableExpr.fromExpr(macroCallExpr)
 .allNodes()
 .filter(node -> node.getKind().equals(Kind.COMPREHENSION))
 .filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .map(CelNavigableMutableExpr::expr)
 .forEach(
 node -> {
Expand All@@ -808,7 +956,7 @@ private CelMutableSource normalizeMacroSource(
 // This can occur from pulling out a nested comprehension into a separate cel.block index
 CelNavigableMutableExpr.fromExpr(macroCallExpr)
 .allNodes()
 .filter(node -> node.getKind().equals(Kind.NOT_SET))
 .filter(node -> node.getKind().equals(ExprKind.Kind.NOT_SET))
 .map(CelNavigableMutableExpr::id)
 .filter(id -> !allExprs.containsKey(id))
 .forEach(
Expand DownExpand Up@@ -840,7 +988,7 @@ private CelMutableSource normalizeMacroSource(
 private static void unwrapListArgumentsInMacroCallExpr(
 CelMutableComprehension comprehension, CelMutableExpr newMacroCallExpr) {
 CelMutableExpr accuInit = comprehension.accuInit();
 if (!accuInit.getKind().equals(Kind.LIST) || !accuInit.list().elements().isEmpty()) {
 if (!accuInit.getKind().equals(ExprKind.Kind.LIST) || !accuInit.list().elements().isEmpty()) {
 // Does not contain an extraneous list.
 return;
 }
Expand DownExpand Up@@ -983,4 +1131,53 @@ private static MangledComprehensionName of(
 iterVarName, iterVar2Name, resultName);
 }
 }

 /**
 * Represents a planned subtree replacement containing the target node ID to replace and either a
 * {@link CelMutableExpr} or {@link CelMutableAst}.
 */
 @AutoValue
 public abstract static class SubtreeReplacement {

 public abstract long exprIdToReplace();

 public abstract Replacement replacement();

 public static SubtreeReplacement of(long exprIdToReplace, CelMutableExpr replacementExpr) {
 return new AutoValue_AstMutator_SubtreeReplacement(
 exprIdToReplace, Replacement.ofExpr(replacementExpr));
 }

 public static SubtreeReplacement of(long exprIdToReplace, CelMutableAst replacementAst) {
 return new AutoValue_AstMutator_SubtreeReplacement(
 exprIdToReplace, Replacement.ofAst(replacementAst));
 }

 /** Discriminated union of either a {@link CelMutableExpr} or a {@link CelMutableAst}. */
 @AutoOneOf(Replacement.Kind.class)
 public abstract static class Replacement {

 public abstract CelMutableExpr expr();

 public abstract CelMutableAst ast();

 public abstract Replacement.Kind kind();

 public static Replacement ofExpr(CelMutableExpr expr) {
 return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.expr(
 Preconditions.checkNotNull(expr));
 }

 public static Replacement ofAst(CelMutableAst ast) {
 return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.ast(
 Preconditions.checkNotNull(ast));
 }

 /** Kind of {@link Replacement}. */
 public enum Kind {
 EXPR,
 AST
 }
 }
 }
}

1 change: 1 addition & 0 deletions
optimizer/src/main/java/dev/cel/optimizer/optimizers/BUILD.bazel

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -96,6 +96,7 @@ java_library(
 "//common:operator",
 "//common/ast",
 "//common/ast:mutable_expr",
 "//common/navigation:common",
 "//common/navigation:expr_util",
 "//common/navigation:mutable_navigation",
 "//common/types",
Expand Down
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Add helpers for performing fixed point optimization#1176

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copybara-service
merged 1 commit into

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Aug 10, 2026
 Merged


Add helpers for performing fixed point optimization
#1176
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221 changes: 209 additions & 12 deletions
optimizer/src/main/java/dev/cel/optimizer/AstMutator.java

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Original file line numberDiff line numberDiff line change
Expand Up@@ -18,17 +18,19 @@
import static java.lang.Math.max;
import static java.util.stream.Collectors.toCollection;

import com.google.auto.value.AutoOneOf;
import com.google.auto.value.AutoValue;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.HashBasedTable;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Streams;
import com.google.common.collect.Table;
import com.google.errorprone.annotations.Immutable;
import dev.cel.common.CelAbstractSyntaxTree;
import dev.cel.common.CelMutableAst;
import dev.cel.common.CelMutableSource;
import dev.cel.common.ast.CelExpr.ExprKind.Kind;
import dev.cel.common.ast.CelExpr.ExprKind;
import dev.cel.common.ast.CelExprIdGeneratorFactory;
import dev.cel.common.ast.CelExprIdGeneratorFactory.ExprIdGenerator;
import dev.cel.common.ast.CelExprIdGeneratorFactory.StableIdGenerator;
Expand All@@ -49,6 +51,7 @@
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Collectors;

Expand DownExpand Up@@ -213,7 +216,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 Predicate<CelNavigableMutableExpr> comprehensionIdentifierPredicate = x -> true;
 comprehensionIdentifierPredicate =
 comprehensionIdentifierPredicate
 .and(node -> node.getKind().equals(Kind.COMPREHENSION))
 .and(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .and(node -> !node.expr().comprehension().iterVar().startsWith(newIterVarPrefix + ":"))
 .and(node -> !node.expr().comprehension().accuVar().startsWith(newAccuVarPrefix + ":"))
 .and(
Expand All@@ -235,7 +238,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 String result = node.expr().comprehension().result().ident().name();
 return CelNavigableMutableExpr.fromExpr(node.expr().comprehension().loopStep())
 .allNodes()
 .filter(subNode -> subNode.getKind().equals(Kind.IDENT))
 .filter(subNode -> subNode.getKind().equals(ExprKind.Kind.IDENT))
 .map(subNode -> subNode.expr().ident())
 .anyMatch(
 ident ->
Expand All@@ -259,7 +262,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 .allNodes()
 .filter(
 loopStepNode ->
 loopStepNode.getKind().equals(Kind.IDENT)
 loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
 && loopStepNode.expr().ident().name().equals(iterVar))
 .map(CelNavigableMutableExpr::id)
 .findAny();
Expand All@@ -269,7 +272,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 .filter(
 loopStepNode ->
 !iterVar2.isEmpty()
 && loopStepNode.getKind().equals(Kind.IDENT)
 && loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
 && loopStepNode.expr().ident().name().equals(iterVar2))
 .map(CelNavigableMutableExpr::id)
 .findAny();
Expand DownExpand Up@@ -406,13 +409,13 @@ private static MangledComprehensionName getMangledComprehensionName(
 private static int countComprehensionNestingLevel(CelNavigableMutableExpr comprehensionExpr) {
 return comprehensionExpr
 .descendants()
 .filter(node -> node.getKind().equals(Kind.COMPREHENSION))
 .filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .mapToInt(
 node -> {
 int nestedLevel = 1;
 CelNavigableMutableExpr maybeParent = node.parent().orElse(null);
 while (maybeParent != null && maybeParent.id() != comprehensionExpr.id()) {
 if (maybeParent.getKind().equals(Kind.COMPREHENSION)) {
 if (maybeParent.getKind().equals(ExprKind.Kind.COMPREHENSION)) {
 nestedLevel++;
 }
 maybeParent = maybeParent.parent().orElse(null);
Expand DownExpand Up@@ -552,6 +555,151 @@ public CelMutableAst replaceSubtree(
 return CelMutableAst.of(mutatedRoot, newAstSource);
 }

 /**
 * Replaces a subtree in the given AST with the specified {@link SubtreeReplacement}.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes. The renumbering occurs even if the subtree was not replaced.
 *
 * @param ast Original AST to mutate.
 * @param replacement Subtree replacement containing the target node ID and the new expression or
 * AST.
 */
 public CelMutableAst replaceSubtree(CelMutableAst ast, SubtreeReplacement replacement) {
 Preconditions.checkNotNull(ast);
 Preconditions.checkNotNull(replacement);
 switch (replacement.replacement().kind()) {
 case EXPR:
 return replaceSubtree(ast, replacement.replacement().expr(), replacement.exprIdToReplace());
 case AST:
 return replaceSubtree(ast, replacement.replacement().ast(), replacement.exprIdToReplace());
 }
 throw new IllegalArgumentException(
 "Unsupported replacement kind: " + replacement.replacement().kind());
 }

 /**
 * Repeatedly applies AST mutations using the provided AST-level rewriter until no further
 * replacements match (fixed point reached) or the mutator's iteration limit is exhausted.
 *
 * <p>Per iteration pass, the AST is traversed to find and perform at most one matching subtree
 * substitution before restarting traversal on the newly mutated AST.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param astRewriter Function returning a {@link SubtreeReplacement} or {@code Optional.empty()}
 * when no further rewrites are possible.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 Function<CelNavigableMutableAst, Optional<SubtreeReplacement>> astRewriter) {
 Preconditions.checkNotNull(ast);
 Preconditions.checkNotNull(astRewriter);
 CelMutableAst mutableAst = ast;
 for (long i = 0; i < iterationLimit; i++) {
 CelNavigableMutableAst navAst = CelNavigableMutableAst.fromAst(mutableAst);
 Optional<SubtreeReplacement> replacement = astRewriter.apply(navAst);
 if (!replacement.isPresent()) {
 return mutableAst;
 }
 mutableAst = replaceSubtree(mutableAst, replacement.get());
 }
 throw new IllegalStateException("Max iteration count reached.");
 }

 /**
 * Traverses nodes using the specified {@link TraversalOrder} and repeatedly rewrites matching
 * subtrees until a fixed point is reached.
 *
 * <p>Per iteration pass, the AST is walked in the given order to find and perform the first
 * matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
 * match or the mutator's iteration limit is exhausted.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param traversalOrder Order in which nodes are visited per iteration pass.
 * @param nodeRewriter Function returning a {@link SubtreeReplacement} or {@code
 * Optional.empty()}.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 TraversalOrder traversalOrder,
 Function<CelNavigableMutableExpr, Optional<SubtreeReplacement>> nodeRewriter) {
 Preconditions.checkNotNull(traversalOrder);
 Preconditions.checkNotNull(nodeRewriter);
 return mutateUntilFixedPoint(
 ast,
 navAst ->
 navAst
 .getRoot()
 .allNodes(traversalOrder)
 .flatMap(node -> Streams.stream(nodeRewriter.apply(node)))
 .findFirst());
 }

 /**
 * Traverses nodes using the specified {@link TraversalOrder}, applies the node matcher, and
 * substitutes matching nodes with the returned replacement expression (targeting {@code
 * node.id()}).
 *
 * <p>Per iteration pass, the AST is walked in the given order to find and perform the first
 * matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
 * match or the mutator's iteration limit is exhausted.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param traversalOrder Order in which nodes are visited per iteration pass.
 * @param nodeMatcher Predicate to filter candidate nodes.
 * @param nodeRewriter Function producing the new {@link CelMutableExpr} for matched nodes.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 TraversalOrder traversalOrder,
 Predicate<CelNavigableMutableExpr> nodeMatcher,
 Function<CelNavigableMutableExpr, Optional<CelMutableExpr>> nodeRewriter) {
 Preconditions.checkNotNull(nodeMatcher);
 Preconditions.checkNotNull(nodeRewriter);
 return mutateUntilFixedPoint(
 ast,
 traversalOrder,
 node ->
 nodeMatcher.test(node)
 ? nodeRewriter.apply(node).map(newExpr -> SubtreeReplacement.of(node.id(), newExpr))
 : Optional.empty());
 }

 private CelMutableExpr mangleIdentsInComprehensionExpr(
 CelMutableExpr root,
 CelMutableExpr comprehensionExpr,
Expand DownExpand Up@@ -590,7 +738,7 @@ private void replaceIdentName(
 .map(CelNavigableMutableExpr::expr)
 .filter(
 node ->
 node.getKind().equals(Kind.IDENT)
 node.getKind().equals(ExprKind.Kind.IDENT)
 && node.ident().name().equals(originalIdentName))
 .findAny()
 .orElse(null);
Expand DownExpand Up@@ -776,7 +924,7 @@ private CelMutableSource normalizeMacroSource(
 long replacedId = idGenerator.generate(exprIdToReplace);
 boolean isListExprBeingReplaced =
 allExprs.containsKey(replacedId)
 && allExprs.get(replacedId).getKind().equals(Kind.LIST);
 && allExprs.get(replacedId).getKind().equals(ExprKind.Kind.LIST);
 if (isListExprBeingReplaced) {
 unwrapListArgumentsInMacroCallExpr(
 allExprs.get(callId).comprehension(), newMacroCallExpr);
Expand All@@ -791,7 +939,7 @@ private CelMutableSource normalizeMacroSource(
 CelMutableExpr macroCallExpr = macroCall.getValue();
 CelNavigableMutableExpr.fromExpr(macroCallExpr)
 .allNodes()
 .filter(node -> node.getKind().equals(Kind.COMPREHENSION))
 .filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .map(CelNavigableMutableExpr::expr)
 .forEach(
 node -> {
Expand All@@ -808,7 +956,7 @@ private CelMutableSource normalizeMacroSource(
 // This can occur from pulling out a nested comprehension into a separate cel.block index
 CelNavigableMutableExpr.fromExpr(macroCallExpr)
 .allNodes()
 .filter(node -> node.getKind().equals(Kind.NOT_SET))
 .filter(node -> node.getKind().equals(ExprKind.Kind.NOT_SET))
 .map(CelNavigableMutableExpr::id)
 .filter(id -> !allExprs.containsKey(id))
 .forEach(
Expand DownExpand Up@@ -840,7 +988,7 @@ private CelMutableSource normalizeMacroSource(
 private static void unwrapListArgumentsInMacroCallExpr(
 CelMutableComprehension comprehension, CelMutableExpr newMacroCallExpr) {
 CelMutableExpr accuInit = comprehension.accuInit();
 if (!accuInit.getKind().equals(Kind.LIST) || !accuInit.list().elements().isEmpty()) {
 if (!accuInit.getKind().equals(ExprKind.Kind.LIST) || !accuInit.list().elements().isEmpty()) {
 // Does not contain an extraneous list.
 return;
 }
Expand DownExpand Up@@ -983,4 +1131,53 @@ private static MangledComprehensionName of(
 iterVarName, iterVar2Name, resultName);
 }
 }

 /**
 * Represents a planned subtree replacement containing the target node ID to replace and either a
 * {@link CelMutableExpr} or {@link CelMutableAst}.
 */
 @AutoValue
 public abstract static class SubtreeReplacement {

 public abstract long exprIdToReplace();

 public abstract Replacement replacement();

 public static SubtreeReplacement of(long exprIdToReplace, CelMutableExpr replacementExpr) {
 return new AutoValue_AstMutator_SubtreeReplacement(
 exprIdToReplace, Replacement.ofExpr(replacementExpr));
 }

 public static SubtreeReplacement of(long exprIdToReplace, CelMutableAst replacementAst) {
 return new AutoValue_AstMutator_SubtreeReplacement(
 exprIdToReplace, Replacement.ofAst(replacementAst));
 }

 /** Discriminated union of either a {@link CelMutableExpr} or a {@link CelMutableAst}. */
 @AutoOneOf(Replacement.Kind.class)
 public abstract static class Replacement {

 public abstract CelMutableExpr expr();

 public abstract CelMutableAst ast();

 public abstract Replacement.Kind kind();

 public static Replacement ofExpr(CelMutableExpr expr) {
 return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.expr(
 Preconditions.checkNotNull(expr));
 }

 public static Replacement ofAst(CelMutableAst ast) {
 return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.ast(
 Preconditions.checkNotNull(ast));
 }

 /** Kind of {@link Replacement}. */
 public enum Kind {
 EXPR,
 AST
 }
 }
 }
}

1 change: 1 addition & 0 deletions
optimizer/src/main/java/dev/cel/optimizer/optimizers/BUILD.bazel

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -96,6 +96,7 @@ java_library(
 "//common:operator",
 "//common/ast",
 "//common/ast:mutable_expr",
 "//common/navigation:common",
 "//common/navigation:expr_util",
 "//common/navigation:mutable_navigation",
 "//common/types",
Expand Down
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Add helpers for performing fixed point optimization#1176

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privacy statement. We’ll occasionally send you account related emails.

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to your account

 Merged

copybara-service
merged 1 commit into

from

Aug 10, 2026
 Merged


Add helpers for performing fixed point optimization
#1176
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221 changes: 209 additions & 12 deletions
optimizer/src/main/java/dev/cel/optimizer/AstMutator.java

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Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -18,17 +18,19 @@
import static java.lang.Math.max;
import static java.util.stream.Collectors.toCollection;

import com.google.auto.value.AutoOneOf;
import com.google.auto.value.AutoValue;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.HashBasedTable;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Streams;
import com.google.common.collect.Table;
import com.google.errorprone.annotations.Immutable;
import dev.cel.common.CelAbstractSyntaxTree;
import dev.cel.common.CelMutableAst;
import dev.cel.common.CelMutableSource;
import dev.cel.common.ast.CelExpr.ExprKind.Kind;
import dev.cel.common.ast.CelExpr.ExprKind;
import dev.cel.common.ast.CelExprIdGeneratorFactory;
import dev.cel.common.ast.CelExprIdGeneratorFactory.ExprIdGenerator;
import dev.cel.common.ast.CelExprIdGeneratorFactory.StableIdGenerator;
Expand All@@ -49,6 +51,7 @@
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Collectors;

Expand DownExpand Up@@ -213,7 +216,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 Predicate<CelNavigableMutableExpr> comprehensionIdentifierPredicate = x -> true;
 comprehensionIdentifierPredicate =
 comprehensionIdentifierPredicate
 .and(node -> node.getKind().equals(Kind.COMPREHENSION))
 .and(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .and(node -> !node.expr().comprehension().iterVar().startsWith(newIterVarPrefix + ":"))
 .and(node -> !node.expr().comprehension().accuVar().startsWith(newAccuVarPrefix + ":"))
 .and(
Expand All@@ -235,7 +238,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 String result = node.expr().comprehension().result().ident().name();
 return CelNavigableMutableExpr.fromExpr(node.expr().comprehension().loopStep())
 .allNodes()
 .filter(subNode -> subNode.getKind().equals(Kind.IDENT))
 .filter(subNode -> subNode.getKind().equals(ExprKind.Kind.IDENT))
 .map(subNode -> subNode.expr().ident())
 .anyMatch(
 ident ->
Expand All@@ -259,7 +262,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 .allNodes()
 .filter(
 loopStepNode ->
 loopStepNode.getKind().equals(Kind.IDENT)
 loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
 && loopStepNode.expr().ident().name().equals(iterVar))
 .map(CelNavigableMutableExpr::id)
 .findAny();
Expand All@@ -269,7 +272,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 .filter(
 loopStepNode ->
 !iterVar2.isEmpty()
 && loopStepNode.getKind().equals(Kind.IDENT)
 && loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
 && loopStepNode.expr().ident().name().equals(iterVar2))
 .map(CelNavigableMutableExpr::id)
 .findAny();
Expand DownExpand Up@@ -406,13 +409,13 @@ private static MangledComprehensionName getMangledComprehensionName(
 private static int countComprehensionNestingLevel(CelNavigableMutableExpr comprehensionExpr) {
 return comprehensionExpr
 .descendants()
 .filter(node -> node.getKind().equals(Kind.COMPREHENSION))
 .filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .mapToInt(
 node -> {
 int nestedLevel = 1;
 CelNavigableMutableExpr maybeParent = node.parent().orElse(null);
 while (maybeParent != null && maybeParent.id() != comprehensionExpr.id()) {
 if (maybeParent.getKind().equals(Kind.COMPREHENSION)) {
 if (maybeParent.getKind().equals(ExprKind.Kind.COMPREHENSION)) {
 nestedLevel++;
 }
 maybeParent = maybeParent.parent().orElse(null);
Expand DownExpand Up@@ -552,6 +555,151 @@ public CelMutableAst replaceSubtree(
 return CelMutableAst.of(mutatedRoot, newAstSource);
 }

 /**
 * Replaces a subtree in the given AST with the specified {@link SubtreeReplacement}.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes. The renumbering occurs even if the subtree was not replaced.
 *
 * @param ast Original AST to mutate.
 * @param replacement Subtree replacement containing the target node ID and the new expression or
 * AST.
 */
 public CelMutableAst replaceSubtree(CelMutableAst ast, SubtreeReplacement replacement) {
 Preconditions.checkNotNull(ast);
 Preconditions.checkNotNull(replacement);
 switch (replacement.replacement().kind()) {
 case EXPR:
 return replaceSubtree(ast, replacement.replacement().expr(), replacement.exprIdToReplace());
 case AST:
 return replaceSubtree(ast, replacement.replacement().ast(), replacement.exprIdToReplace());
 }
 throw new IllegalArgumentException(
 "Unsupported replacement kind: " + replacement.replacement().kind());
 }

 /**
 * Repeatedly applies AST mutations using the provided AST-level rewriter until no further
 * replacements match (fixed point reached) or the mutator's iteration limit is exhausted.
 *
 * <p>Per iteration pass, the AST is traversed to find and perform at most one matching subtree
 * substitution before restarting traversal on the newly mutated AST.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param astRewriter Function returning a {@link SubtreeReplacement} or {@code Optional.empty()}
 * when no further rewrites are possible.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 Function<CelNavigableMutableAst, Optional<SubtreeReplacement>> astRewriter) {
 Preconditions.checkNotNull(ast);
 Preconditions.checkNotNull(astRewriter);
 CelMutableAst mutableAst = ast;
 for (long i = 0; i < iterationLimit; i++) {
 CelNavigableMutableAst navAst = CelNavigableMutableAst.fromAst(mutableAst);
 Optional<SubtreeReplacement> replacement = astRewriter.apply(navAst);
 if (!replacement.isPresent()) {
 return mutableAst;
 }
 mutableAst = replaceSubtree(mutableAst, replacement.get());
 }
 throw new IllegalStateException("Max iteration count reached.");
 }

 /**
 * Traverses nodes using the specified {@link TraversalOrder} and repeatedly rewrites matching
 * subtrees until a fixed point is reached.
 *
 * <p>Per iteration pass, the AST is walked in the given order to find and perform the first
 * matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
 * match or the mutator's iteration limit is exhausted.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param traversalOrder Order in which nodes are visited per iteration pass.
 * @param nodeRewriter Function returning a {@link SubtreeReplacement} or {@code
 * Optional.empty()}.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 TraversalOrder traversalOrder,
 Function<CelNavigableMutableExpr, Optional<SubtreeReplacement>> nodeRewriter) {
 Preconditions.checkNotNull(traversalOrder);
 Preconditions.checkNotNull(nodeRewriter);
 return mutateUntilFixedPoint(
 ast,
 navAst ->
 navAst
 .getRoot()
 .allNodes(traversalOrder)
 .flatMap(node -> Streams.stream(nodeRewriter.apply(node)))
 .findFirst());
 }

 /**
 * Traverses nodes using the specified {@link TraversalOrder}, applies the node matcher, and
 * substitutes matching nodes with the returned replacement expression (targeting {@code
 * node.id()}).
 *
 * <p>Per iteration pass, the AST is walked in the given order to find and perform the first
 * matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
 * match or the mutator's iteration limit is exhausted.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param traversalOrder Order in which nodes are visited per iteration pass.
 * @param nodeMatcher Predicate to filter candidate nodes.
 * @param nodeRewriter Function producing the new {@link CelMutableExpr} for matched nodes.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 TraversalOrder traversalOrder,
 Predicate<CelNavigableMutableExpr> nodeMatcher,
 Function<CelNavigableMutableExpr, Optional<CelMutableExpr>> nodeRewriter) {
 Preconditions.checkNotNull(nodeMatcher);
 Preconditions.checkNotNull(nodeRewriter);
 return mutateUntilFixedPoint(
 ast,
 traversalOrder,
 node ->
 nodeMatcher.test(node)
 ? nodeRewriter.apply(node).map(newExpr -> SubtreeReplacement.of(node.id(), newExpr))
 : Optional.empty());
 }

 private CelMutableExpr mangleIdentsInComprehensionExpr(
 CelMutableExpr root,
 CelMutableExpr comprehensionExpr,
Expand DownExpand Up@@ -590,7 +738,7 @@ private void replaceIdentName(
 .map(CelNavigableMutableExpr::expr)
 .filter(
 node ->
 node.getKind().equals(Kind.IDENT)
 node.getKind().equals(ExprKind.Kind.IDENT)
 && node.ident().name().equals(originalIdentName))
 .findAny()
 .orElse(null);
Expand DownExpand Up@@ -776,7 +924,7 @@ private CelMutableSource normalizeMacroSource(
 long replacedId = idGenerator.generate(exprIdToReplace);
 boolean isListExprBeingReplaced =
 allExprs.containsKey(replacedId)
 && allExprs.get(replacedId).getKind().equals(Kind.LIST);
 && allExprs.get(replacedId).getKind().equals(ExprKind.Kind.LIST);
 if (isListExprBeingReplaced) {
 unwrapListArgumentsInMacroCallExpr(
 allExprs.get(callId).comprehension(), newMacroCallExpr);
Expand All@@ -791,7 +939,7 @@ private CelMutableSource normalizeMacroSource(
 CelMutableExpr macroCallExpr = macroCall.getValue();
 CelNavigableMutableExpr.fromExpr(macroCallExpr)
 .allNodes()
 .filter(node -> node.getKind().equals(Kind.COMPREHENSION))
 .filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .map(CelNavigableMutableExpr::expr)
 .forEach(
 node -> {
Expand All@@ -808,7 +956,7 @@ private CelMutableSource normalizeMacroSource(
 // This can occur from pulling out a nested comprehension into a separate cel.block index
 CelNavigableMutableExpr.fromExpr(macroCallExpr)
 .allNodes()
 .filter(node -> node.getKind().equals(Kind.NOT_SET))
 .filter(node -> node.getKind().equals(ExprKind.Kind.NOT_SET))
 .map(CelNavigableMutableExpr::id)
 .filter(id -> !allExprs.containsKey(id))
 .forEach(
Expand DownExpand Up@@ -840,7 +988,7 @@ private CelMutableSource normalizeMacroSource(
 private static void unwrapListArgumentsInMacroCallExpr(
 CelMutableComprehension comprehension, CelMutableExpr newMacroCallExpr) {
 CelMutableExpr accuInit = comprehension.accuInit();
 if (!accuInit.getKind().equals(Kind.LIST) || !accuInit.list().elements().isEmpty()) {
 if (!accuInit.getKind().equals(ExprKind.Kind.LIST) || !accuInit.list().elements().isEmpty()) {
 // Does not contain an extraneous list.
 return;
 }
Expand DownExpand Up@@ -983,4 +1131,53 @@ private static MangledComprehensionName of(
 iterVarName, iterVar2Name, resultName);
 }
 }

 /**
 * Represents a planned subtree replacement containing the target node ID to replace and either a
 * {@link CelMutableExpr} or {@link CelMutableAst}.
 */
 @AutoValue
 public abstract static class SubtreeReplacement {

 public abstract long exprIdToReplace();

 public abstract Replacement replacement();

 public static SubtreeReplacement of(long exprIdToReplace, CelMutableExpr replacementExpr) {
 return new AutoValue_AstMutator_SubtreeReplacement(
 exprIdToReplace, Replacement.ofExpr(replacementExpr));
 }

 public static SubtreeReplacement of(long exprIdToReplace, CelMutableAst replacementAst) {
 return new AutoValue_AstMutator_SubtreeReplacement(
 exprIdToReplace, Replacement.ofAst(replacementAst));
 }

 /** Discriminated union of either a {@link CelMutableExpr} or a {@link CelMutableAst}. */
 @AutoOneOf(Replacement.Kind.class)
 public abstract static class Replacement {

 public abstract CelMutableExpr expr();

 public abstract CelMutableAst ast();

 public abstract Replacement.Kind kind();

 public static Replacement ofExpr(CelMutableExpr expr) {
 return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.expr(
 Preconditions.checkNotNull(expr));
 }

 public static Replacement ofAst(CelMutableAst ast) {
 return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.ast(
 Preconditions.checkNotNull(ast));
 }

 /** Kind of {@link Replacement}. */
 public enum Kind {
 EXPR,
 AST
 }
 }
 }
}

1 change: 1 addition & 0 deletions
optimizer/src/main/java/dev/cel/optimizer/optimizers/BUILD.bazel

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -96,6 +96,7 @@ java_library(
 "//common:operator",
 "//common/ast",
 "//common/ast:mutable_expr",
 "//common/navigation:common",
 "//common/navigation:expr_util",
 "//common/navigation:mutable_navigation",
 "//common/types",
Expand Down
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

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Add helpers for performing fixed point optimization#1176

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 Merged

copybara-service
merged 1 commit into

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Aug 10, 2026
 Merged


Add helpers for performing fixed point optimization
#1176
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221 changes: 209 additions & 12 deletions
optimizer/src/main/java/dev/cel/optimizer/AstMutator.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -18,17 +18,19 @@
import static java.lang.Math.max;
import static java.util.stream.Collectors.toCollection;

import com.google.auto.value.AutoOneOf;
import com.google.auto.value.AutoValue;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.HashBasedTable;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Streams;
import com.google.common.collect.Table;
import com.google.errorprone.annotations.Immutable;
import dev.cel.common.CelAbstractSyntaxTree;
import dev.cel.common.CelMutableAst;
import dev.cel.common.CelMutableSource;
import dev.cel.common.ast.CelExpr.ExprKind.Kind;
import dev.cel.common.ast.CelExpr.ExprKind;
import dev.cel.common.ast.CelExprIdGeneratorFactory;
import dev.cel.common.ast.CelExprIdGeneratorFactory.ExprIdGenerator;
import dev.cel.common.ast.CelExprIdGeneratorFactory.StableIdGenerator;
Expand All@@ -49,6 +51,7 @@
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Collectors;

Expand DownExpand Up@@ -213,7 +216,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 Predicate<CelNavigableMutableExpr> comprehensionIdentifierPredicate = x -> true;
 comprehensionIdentifierPredicate =
 comprehensionIdentifierPredicate
 .and(node -> node.getKind().equals(Kind.COMPREHENSION))
 .and(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .and(node -> !node.expr().comprehension().iterVar().startsWith(newIterVarPrefix + ":"))
 .and(node -> !node.expr().comprehension().accuVar().startsWith(newAccuVarPrefix + ":"))
 .and(
Expand All@@ -235,7 +238,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 String result = node.expr().comprehension().result().ident().name();
 return CelNavigableMutableExpr.fromExpr(node.expr().comprehension().loopStep())
 .allNodes()
 .filter(subNode -> subNode.getKind().equals(Kind.IDENT))
 .filter(subNode -> subNode.getKind().equals(ExprKind.Kind.IDENT))
 .map(subNode -> subNode.expr().ident())
 .anyMatch(
 ident ->
Expand All@@ -259,7 +262,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 .allNodes()
 .filter(
 loopStepNode ->
 loopStepNode.getKind().equals(Kind.IDENT)
 loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
 && loopStepNode.expr().ident().name().equals(iterVar))
 .map(CelNavigableMutableExpr::id)
 .findAny();
Expand All@@ -269,7 +272,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 .filter(
 loopStepNode ->
 !iterVar2.isEmpty()
 && loopStepNode.getKind().equals(Kind.IDENT)
 && loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
 && loopStepNode.expr().ident().name().equals(iterVar2))
 .map(CelNavigableMutableExpr::id)
 .findAny();
Expand DownExpand Up@@ -406,13 +409,13 @@ private static MangledComprehensionName getMangledComprehensionName(
 private static int countComprehensionNestingLevel(CelNavigableMutableExpr comprehensionExpr) {
 return comprehensionExpr
 .descendants()
 .filter(node -> node.getKind().equals(Kind.COMPREHENSION))
 .filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .mapToInt(
 node -> {
 int nestedLevel = 1;
 CelNavigableMutableExpr maybeParent = node.parent().orElse(null);
 while (maybeParent != null && maybeParent.id() != comprehensionExpr.id()) {
 if (maybeParent.getKind().equals(Kind.COMPREHENSION)) {
 if (maybeParent.getKind().equals(ExprKind.Kind.COMPREHENSION)) {
 nestedLevel++;
 }
 maybeParent = maybeParent.parent().orElse(null);
Expand DownExpand Up@@ -552,6 +555,151 @@ public CelMutableAst replaceSubtree(
 return CelMutableAst.of(mutatedRoot, newAstSource);
 }

 /**
 * Replaces a subtree in the given AST with the specified {@link SubtreeReplacement}.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes. The renumbering occurs even if the subtree was not replaced.
 *
 * @param ast Original AST to mutate.
 * @param replacement Subtree replacement containing the target node ID and the new expression or
 * AST.
 */
 public CelMutableAst replaceSubtree(CelMutableAst ast, SubtreeReplacement replacement) {
 Preconditions.checkNotNull(ast);
 Preconditions.checkNotNull(replacement);
 switch (replacement.replacement().kind()) {
 case EXPR:
 return replaceSubtree(ast, replacement.replacement().expr(), replacement.exprIdToReplace());
 case AST:
 return replaceSubtree(ast, replacement.replacement().ast(), replacement.exprIdToReplace());
 }
 throw new IllegalArgumentException(
 "Unsupported replacement kind: " + replacement.replacement().kind());
 }

 /**
 * Repeatedly applies AST mutations using the provided AST-level rewriter until no further
 * replacements match (fixed point reached) or the mutator's iteration limit is exhausted.
 *
 * <p>Per iteration pass, the AST is traversed to find and perform at most one matching subtree
 * substitution before restarting traversal on the newly mutated AST.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param astRewriter Function returning a {@link SubtreeReplacement} or {@code Optional.empty()}
 * when no further rewrites are possible.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 Function<CelNavigableMutableAst, Optional<SubtreeReplacement>> astRewriter) {
 Preconditions.checkNotNull(ast);
 Preconditions.checkNotNull(astRewriter);
 CelMutableAst mutableAst = ast;
 for (long i = 0; i < iterationLimit; i++) {
 CelNavigableMutableAst navAst = CelNavigableMutableAst.fromAst(mutableAst);
 Optional<SubtreeReplacement> replacement = astRewriter.apply(navAst);
 if (!replacement.isPresent()) {
 return mutableAst;
 }
 mutableAst = replaceSubtree(mutableAst, replacement.get());
 }
 throw new IllegalStateException("Max iteration count reached.");
 }

 /**
 * Traverses nodes using the specified {@link TraversalOrder} and repeatedly rewrites matching
 * subtrees until a fixed point is reached.
 *
 * <p>Per iteration pass, the AST is walked in the given order to find and perform the first
 * matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
 * match or the mutator's iteration limit is exhausted.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param traversalOrder Order in which nodes are visited per iteration pass.
 * @param nodeRewriter Function returning a {@link SubtreeReplacement} or {@code
 * Optional.empty()}.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 TraversalOrder traversalOrder,
 Function<CelNavigableMutableExpr, Optional<SubtreeReplacement>> nodeRewriter) {
 Preconditions.checkNotNull(traversalOrder);
 Preconditions.checkNotNull(nodeRewriter);
 return mutateUntilFixedPoint(
 ast,
 navAst ->
 navAst
 .getRoot()
 .allNodes(traversalOrder)
 .flatMap(node -> Streams.stream(nodeRewriter.apply(node)))
 .findFirst());
 }

 /**
 * Traverses nodes using the specified {@link TraversalOrder}, applies the node matcher, and
 * substitutes matching nodes with the returned replacement expression (targeting {@code
 * node.id()}).
 *
 * <p>Per iteration pass, the AST is walked in the given order to find and perform the first
 * matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
 * match or the mutator's iteration limit is exhausted.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param traversalOrder Order in which nodes are visited per iteration pass.
 * @param nodeMatcher Predicate to filter candidate nodes.
 * @param nodeRewriter Function producing the new {@link CelMutableExpr} for matched nodes.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 TraversalOrder traversalOrder,
 Predicate<CelNavigableMutableExpr> nodeMatcher,
 Function<CelNavigableMutableExpr, Optional<CelMutableExpr>> nodeRewriter) {
 Preconditions.checkNotNull(nodeMatcher);
 Preconditions.checkNotNull(nodeRewriter);
 return mutateUntilFixedPoint(
 ast,
 traversalOrder,
 node ->
 nodeMatcher.test(node)
 ? nodeRewriter.apply(node).map(newExpr -> SubtreeReplacement.of(node.id(), newExpr))
 : Optional.empty());
 }

 private CelMutableExpr mangleIdentsInComprehensionExpr(
 CelMutableExpr root,
 CelMutableExpr comprehensionExpr,
Expand DownExpand Up@@ -590,7 +738,7 @@ private void replaceIdentName(
 .map(CelNavigableMutableExpr::expr)
 .filter(
 node ->
 node.getKind().equals(Kind.IDENT)
 node.getKind().equals(ExprKind.Kind.IDENT)
 && node.ident().name().equals(originalIdentName))
 .findAny()
 .orElse(null);
Expand DownExpand Up@@ -776,7 +924,7 @@ private CelMutableSource normalizeMacroSource(
 long replacedId = idGenerator.generate(exprIdToReplace);
 boolean isListExprBeingReplaced =
 allExprs.containsKey(replacedId)
 && allExprs.get(replacedId).getKind().equals(Kind.LIST);
 && allExprs.get(replacedId).getKind().equals(ExprKind.Kind.LIST);
 if (isListExprBeingReplaced) {
 unwrapListArgumentsInMacroCallExpr(
 allExprs.get(callId).comprehension(), newMacroCallExpr);
Expand All@@ -791,7 +939,7 @@ private CelMutableSource normalizeMacroSource(
 CelMutableExpr macroCallExpr = macroCall.getValue();
 CelNavigableMutableExpr.fromExpr(macroCallExpr)
 .allNodes()
 .filter(node -> node.getKind().equals(Kind.COMPREHENSION))
 .filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .map(CelNavigableMutableExpr::expr)
 .forEach(
 node -> {
Expand All@@ -808,7 +956,7 @@ private CelMutableSource normalizeMacroSource(
 // This can occur from pulling out a nested comprehension into a separate cel.block index
 CelNavigableMutableExpr.fromExpr(macroCallExpr)
 .allNodes()
 .filter(node -> node.getKind().equals(Kind.NOT_SET))
 .filter(node -> node.getKind().equals(ExprKind.Kind.NOT_SET))
 .map(CelNavigableMutableExpr::id)
 .filter(id -> !allExprs.containsKey(id))
 .forEach(
Expand DownExpand Up@@ -840,7 +988,7 @@ private CelMutableSource normalizeMacroSource(
 private static void unwrapListArgumentsInMacroCallExpr(
 CelMutableComprehension comprehension, CelMutableExpr newMacroCallExpr) {
 CelMutableExpr accuInit = comprehension.accuInit();
 if (!accuInit.getKind().equals(Kind.LIST) || !accuInit.list().elements().isEmpty()) {
 if (!accuInit.getKind().equals(ExprKind.Kind.LIST) || !accuInit.list().elements().isEmpty()) {
 // Does not contain an extraneous list.
 return;
 }
Expand DownExpand Up@@ -983,4 +1131,53 @@ private static MangledComprehensionName of(
 iterVarName, iterVar2Name, resultName);
 }
 }

 /**
 * Represents a planned subtree replacement containing the target node ID to replace and either a
 * {@link CelMutableExpr} or {@link CelMutableAst}.
 */
 @AutoValue
 public abstract static class SubtreeReplacement {

 public abstract long exprIdToReplace();

 public abstract Replacement replacement();

 public static SubtreeReplacement of(long exprIdToReplace, CelMutableExpr replacementExpr) {
 return new AutoValue_AstMutator_SubtreeReplacement(
 exprIdToReplace, Replacement.ofExpr(replacementExpr));
 }

 public static SubtreeReplacement of(long exprIdToReplace, CelMutableAst replacementAst) {
 return new AutoValue_AstMutator_SubtreeReplacement(
 exprIdToReplace, Replacement.ofAst(replacementAst));
 }

 /** Discriminated union of either a {@link CelMutableExpr} or a {@link CelMutableAst}. */
 @AutoOneOf(Replacement.Kind.class)
 public abstract static class Replacement {

 public abstract CelMutableExpr expr();

 public abstract CelMutableAst ast();

 public abstract Replacement.Kind kind();

 public static Replacement ofExpr(CelMutableExpr expr) {
 return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.expr(
 Preconditions.checkNotNull(expr));
 }

 public static Replacement ofAst(CelMutableAst ast) {
 return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.ast(
 Preconditions.checkNotNull(ast));
 }

 /** Kind of {@link Replacement}. */
 public enum Kind {
 EXPR,
 AST
 }
 }
 }
}

1 change: 1 addition & 0 deletions
optimizer/src/main/java/dev/cel/optimizer/optimizers/BUILD.bazel

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -96,6 +96,7 @@ java_library(
 "//common:operator",
 "//common/ast",
 "//common/ast:mutable_expr",
 "//common/navigation:common",
 "//common/navigation:expr_util",
 "//common/navigation:mutable_navigation",
 "//common/types",
Expand Down
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

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Add helpers for performing fixed point optimization#1176

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copybara-service
merged 1 commit into

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Aug 10, 2026
 Merged


Add helpers for performing fixed point optimization
#1176
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221 changes: 209 additions & 12 deletions
optimizer/src/main/java/dev/cel/optimizer/AstMutator.java

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Original file line numberDiff line numberDiff line change
Expand Up@@ -18,17 +18,19 @@
import static java.lang.Math.max;
import static java.util.stream.Collectors.toCollection;

import com.google.auto.value.AutoOneOf;
import com.google.auto.value.AutoValue;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.HashBasedTable;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Streams;
import com.google.common.collect.Table;
import com.google.errorprone.annotations.Immutable;
import dev.cel.common.CelAbstractSyntaxTree;
import dev.cel.common.CelMutableAst;
import dev.cel.common.CelMutableSource;
import dev.cel.common.ast.CelExpr.ExprKind.Kind;
import dev.cel.common.ast.CelExpr.ExprKind;
import dev.cel.common.ast.CelExprIdGeneratorFactory;
import dev.cel.common.ast.CelExprIdGeneratorFactory.ExprIdGenerator;
import dev.cel.common.ast.CelExprIdGeneratorFactory.StableIdGenerator;
Expand All@@ -49,6 +51,7 @@
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Collectors;

Expand DownExpand Up@@ -213,7 +216,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 Predicate<CelNavigableMutableExpr> comprehensionIdentifierPredicate = x -> true;
 comprehensionIdentifierPredicate =
 comprehensionIdentifierPredicate
 .and(node -> node.getKind().equals(Kind.COMPREHENSION))
 .and(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .and(node -> !node.expr().comprehension().iterVar().startsWith(newIterVarPrefix + ":"))
 .and(node -> !node.expr().comprehension().accuVar().startsWith(newAccuVarPrefix + ":"))
 .and(
Expand All@@ -235,7 +238,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 String result = node.expr().comprehension().result().ident().name();
 return CelNavigableMutableExpr.fromExpr(node.expr().comprehension().loopStep())
 .allNodes()
 .filter(subNode -> subNode.getKind().equals(Kind.IDENT))
 .filter(subNode -> subNode.getKind().equals(ExprKind.Kind.IDENT))
 .map(subNode -> subNode.expr().ident())
 .anyMatch(
 ident ->
Expand All@@ -259,7 +262,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 .allNodes()
 .filter(
 loopStepNode ->
 loopStepNode.getKind().equals(Kind.IDENT)
 loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
 && loopStepNode.expr().ident().name().equals(iterVar))
 .map(CelNavigableMutableExpr::id)
 .findAny();
Expand All@@ -269,7 +272,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 .filter(
 loopStepNode ->
 !iterVar2.isEmpty()
 && loopStepNode.getKind().equals(Kind.IDENT)
 && loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
 && loopStepNode.expr().ident().name().equals(iterVar2))
 .map(CelNavigableMutableExpr::id)
 .findAny();
Expand DownExpand Up@@ -406,13 +409,13 @@ private static MangledComprehensionName getMangledComprehensionName(
 private static int countComprehensionNestingLevel(CelNavigableMutableExpr comprehensionExpr) {
 return comprehensionExpr
 .descendants()
 .filter(node -> node.getKind().equals(Kind.COMPREHENSION))
 .filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .mapToInt(
 node -> {
 int nestedLevel = 1;
 CelNavigableMutableExpr maybeParent = node.parent().orElse(null);
 while (maybeParent != null && maybeParent.id() != comprehensionExpr.id()) {
 if (maybeParent.getKind().equals(Kind.COMPREHENSION)) {
 if (maybeParent.getKind().equals(ExprKind.Kind.COMPREHENSION)) {
 nestedLevel++;
 }
 maybeParent = maybeParent.parent().orElse(null);
Expand DownExpand Up@@ -552,6 +555,151 @@ public CelMutableAst replaceSubtree(
 return CelMutableAst.of(mutatedRoot, newAstSource);
 }

 /**
 * Replaces a subtree in the given AST with the specified {@link SubtreeReplacement}.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes. The renumbering occurs even if the subtree was not replaced.
 *
 * @param ast Original AST to mutate.
 * @param replacement Subtree replacement containing the target node ID and the new expression or
 * AST.
 */
 public CelMutableAst replaceSubtree(CelMutableAst ast, SubtreeReplacement replacement) {
 Preconditions.checkNotNull(ast);
 Preconditions.checkNotNull(replacement);
 switch (replacement.replacement().kind()) {
 case EXPR:
 return replaceSubtree(ast, replacement.replacement().expr(), replacement.exprIdToReplace());
 case AST:
 return replaceSubtree(ast, replacement.replacement().ast(), replacement.exprIdToReplace());
 }
 throw new IllegalArgumentException(
 "Unsupported replacement kind: " + replacement.replacement().kind());
 }

 /**
 * Repeatedly applies AST mutations using the provided AST-level rewriter until no further
 * replacements match (fixed point reached) or the mutator's iteration limit is exhausted.
 *
 * <p>Per iteration pass, the AST is traversed to find and perform at most one matching subtree
 * substitution before restarting traversal on the newly mutated AST.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param astRewriter Function returning a {@link SubtreeReplacement} or {@code Optional.empty()}
 * when no further rewrites are possible.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 Function<CelNavigableMutableAst, Optional<SubtreeReplacement>> astRewriter) {
 Preconditions.checkNotNull(ast);
 Preconditions.checkNotNull(astRewriter);
 CelMutableAst mutableAst = ast;
 for (long i = 0; i < iterationLimit; i++) {
 CelNavigableMutableAst navAst = CelNavigableMutableAst.fromAst(mutableAst);
 Optional<SubtreeReplacement> replacement = astRewriter.apply(navAst);
 if (!replacement.isPresent()) {
 return mutableAst;
 }
 mutableAst = replaceSubtree(mutableAst, replacement.get());
 }
 throw new IllegalStateException("Max iteration count reached.");
 }

 /**
 * Traverses nodes using the specified {@link TraversalOrder} and repeatedly rewrites matching
 * subtrees until a fixed point is reached.
 *
 * <p>Per iteration pass, the AST is walked in the given order to find and perform the first
 * matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
 * match or the mutator's iteration limit is exhausted.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param traversalOrder Order in which nodes are visited per iteration pass.
 * @param nodeRewriter Function returning a {@link SubtreeReplacement} or {@code
 * Optional.empty()}.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 TraversalOrder traversalOrder,
 Function<CelNavigableMutableExpr, Optional<SubtreeReplacement>> nodeRewriter) {
 Preconditions.checkNotNull(traversalOrder);
 Preconditions.checkNotNull(nodeRewriter);
 return mutateUntilFixedPoint(
 ast,
 navAst ->
 navAst
 .getRoot()
 .allNodes(traversalOrder)
 .flatMap(node -> Streams.stream(nodeRewriter.apply(node)))
 .findFirst());
 }

 /**
 * Traverses nodes using the specified {@link TraversalOrder}, applies the node matcher, and
 * substitutes matching nodes with the returned replacement expression (targeting {@code
 * node.id()}).
 *
 * <p>Per iteration pass, the AST is walked in the given order to find and perform the first
 * matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
 * match or the mutator's iteration limit is exhausted.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param traversalOrder Order in which nodes are visited per iteration pass.
 * @param nodeMatcher Predicate to filter candidate nodes.
 * @param nodeRewriter Function producing the new {@link CelMutableExpr} for matched nodes.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 TraversalOrder traversalOrder,
 Predicate<CelNavigableMutableExpr> nodeMatcher,
 Function<CelNavigableMutableExpr, Optional<CelMutableExpr>> nodeRewriter) {
 Preconditions.checkNotNull(nodeMatcher);
 Preconditions.checkNotNull(nodeRewriter);
 return mutateUntilFixedPoint(
 ast,
 traversalOrder,
 node ->
 nodeMatcher.test(node)
 ? nodeRewriter.apply(node).map(newExpr -> SubtreeReplacement.of(node.id(), newExpr))
 : Optional.empty());
 }

 private CelMutableExpr mangleIdentsInComprehensionExpr(
 CelMutableExpr root,
 CelMutableExpr comprehensionExpr,
Expand DownExpand Up@@ -590,7 +738,7 @@ private void replaceIdentName(
 .map(CelNavigableMutableExpr::expr)
 .filter(
 node ->
 node.getKind().equals(Kind.IDENT)
 node.getKind().equals(ExprKind.Kind.IDENT)
 && node.ident().name().equals(originalIdentName))
 .findAny()
 .orElse(null);
Expand DownExpand Up@@ -776,7 +924,7 @@ private CelMutableSource normalizeMacroSource(
 long replacedId = idGenerator.generate(exprIdToReplace);
 boolean isListExprBeingReplaced =
 allExprs.containsKey(replacedId)
 && allExprs.get(replacedId).getKind().equals(Kind.LIST);
 && allExprs.get(replacedId).getKind().equals(ExprKind.Kind.LIST);
 if (isListExprBeingReplaced) {
 unwrapListArgumentsInMacroCallExpr(
 allExprs.get(callId).comprehension(), newMacroCallExpr);
Expand All@@ -791,7 +939,7 @@ private CelMutableSource normalizeMacroSource(
 CelMutableExpr macroCallExpr = macroCall.getValue();
 CelNavigableMutableExpr.fromExpr(macroCallExpr)
 .allNodes()
 .filter(node -> node.getKind().equals(Kind.COMPREHENSION))
 .filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .map(CelNavigableMutableExpr::expr)
 .forEach(
 node -> {
Expand All@@ -808,7 +956,7 @@ private CelMutableSource normalizeMacroSource(
 // This can occur from pulling out a nested comprehension into a separate cel.block index
 CelNavigableMutableExpr.fromExpr(macroCallExpr)
 .allNodes()
 .filter(node -> node.getKind().equals(Kind.NOT_SET))
 .filter(node -> node.getKind().equals(ExprKind.Kind.NOT_SET))
 .map(CelNavigableMutableExpr::id)
 .filter(id -> !allExprs.containsKey(id))
 .forEach(
Expand DownExpand Up@@ -840,7 +988,7 @@ private CelMutableSource normalizeMacroSource(
 private static void unwrapListArgumentsInMacroCallExpr(
 CelMutableComprehension comprehension, CelMutableExpr newMacroCallExpr) {
 CelMutableExpr accuInit = comprehension.accuInit();
 if (!accuInit.getKind().equals(Kind.LIST) || !accuInit.list().elements().isEmpty()) {
 if (!accuInit.getKind().equals(ExprKind.Kind.LIST) || !accuInit.list().elements().isEmpty()) {
 // Does not contain an extraneous list.
 return;
 }
Expand DownExpand Up@@ -983,4 +1131,53 @@ private static MangledComprehensionName of(
 iterVarName, iterVar2Name, resultName);
 }
 }

 /**
 * Represents a planned subtree replacement containing the target node ID to replace and either a
 * {@link CelMutableExpr} or {@link CelMutableAst}.
 */
 @AutoValue
 public abstract static class SubtreeReplacement {

 public abstract long exprIdToReplace();

 public abstract Replacement replacement();

 public static SubtreeReplacement of(long exprIdToReplace, CelMutableExpr replacementExpr) {
 return new AutoValue_AstMutator_SubtreeReplacement(
 exprIdToReplace, Replacement.ofExpr(replacementExpr));
 }

 public static SubtreeReplacement of(long exprIdToReplace, CelMutableAst replacementAst) {
 return new AutoValue_AstMutator_SubtreeReplacement(
 exprIdToReplace, Replacement.ofAst(replacementAst));
 }

 /** Discriminated union of either a {@link CelMutableExpr} or a {@link CelMutableAst}. */
 @AutoOneOf(Replacement.Kind.class)
 public abstract static class Replacement {

 public abstract CelMutableExpr expr();

 public abstract CelMutableAst ast();

 public abstract Replacement.Kind kind();

 public static Replacement ofExpr(CelMutableExpr expr) {
 return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.expr(
 Preconditions.checkNotNull(expr));
 }

 public static Replacement ofAst(CelMutableAst ast) {
 return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.ast(
 Preconditions.checkNotNull(ast));
 }

 /** Kind of {@link Replacement}. */
 public enum Kind {
 EXPR,
 AST
 }
 }
 }
}

1 change: 1 addition & 0 deletions
optimizer/src/main/java/dev/cel/optimizer/optimizers/BUILD.bazel

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -96,6 +96,7 @@ java_library(
 "//common:operator",
 "//common/ast",
 "//common/ast:mutable_expr",
 "//common/navigation:common",
 "//common/navigation:expr_util",
 "//common/navigation:mutable_navigation",
 "//common/types",
Expand Down
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Add helpers for performing fixed point optimization#1176

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to your account

 Merged

copybara-service
merged 1 commit into

from

Aug 10, 2026
 Merged


Add helpers for performing fixed point optimization
#1176
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221 changes: 209 additions & 12 deletions
optimizer/src/main/java/dev/cel/optimizer/AstMutator.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -18,17 +18,19 @@
import static java.lang.Math.max;
import static java.util.stream.Collectors.toCollection;

import com.google.auto.value.AutoOneOf;
import com.google.auto.value.AutoValue;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.HashBasedTable;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Streams;
import com.google.common.collect.Table;
import com.google.errorprone.annotations.Immutable;
import dev.cel.common.CelAbstractSyntaxTree;
import dev.cel.common.CelMutableAst;
import dev.cel.common.CelMutableSource;
import dev.cel.common.ast.CelExpr.ExprKind.Kind;
import dev.cel.common.ast.CelExpr.ExprKind;
import dev.cel.common.ast.CelExprIdGeneratorFactory;
import dev.cel.common.ast.CelExprIdGeneratorFactory.ExprIdGenerator;
import dev.cel.common.ast.CelExprIdGeneratorFactory.StableIdGenerator;
Expand All@@ -49,6 +51,7 @@
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Collectors;

Expand DownExpand Up@@ -213,7 +216,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 Predicate<CelNavigableMutableExpr> comprehensionIdentifierPredicate = x -> true;
 comprehensionIdentifierPredicate =
 comprehensionIdentifierPredicate
 .and(node -> node.getKind().equals(Kind.COMPREHENSION))
 .and(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .and(node -> !node.expr().comprehension().iterVar().startsWith(newIterVarPrefix + ":"))
 .and(node -> !node.expr().comprehension().accuVar().startsWith(newAccuVarPrefix + ":"))
 .and(
Expand All@@ -235,7 +238,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 String result = node.expr().comprehension().result().ident().name();
 return CelNavigableMutableExpr.fromExpr(node.expr().comprehension().loopStep())
 .allNodes()
 .filter(subNode -> subNode.getKind().equals(Kind.IDENT))
 .filter(subNode -> subNode.getKind().equals(ExprKind.Kind.IDENT))
 .map(subNode -> subNode.expr().ident())
 .anyMatch(
 ident ->
Expand All@@ -259,7 +262,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 .allNodes()
 .filter(
 loopStepNode ->
 loopStepNode.getKind().equals(Kind.IDENT)
 loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
 && loopStepNode.expr().ident().name().equals(iterVar))
 .map(CelNavigableMutableExpr::id)
 .findAny();
Expand All@@ -269,7 +272,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 .filter(
 loopStepNode ->
 !iterVar2.isEmpty()
 && loopStepNode.getKind().equals(Kind.IDENT)
 && loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
 && loopStepNode.expr().ident().name().equals(iterVar2))
 .map(CelNavigableMutableExpr::id)
 .findAny();
Expand DownExpand Up@@ -406,13 +409,13 @@ private static MangledComprehensionName getMangledComprehensionName(
 private static int countComprehensionNestingLevel(CelNavigableMutableExpr comprehensionExpr) {
 return comprehensionExpr
 .descendants()
 .filter(node -> node.getKind().equals(Kind.COMPREHENSION))
 .filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .mapToInt(
 node -> {
 int nestedLevel = 1;
 CelNavigableMutableExpr maybeParent = node.parent().orElse(null);
 while (maybeParent != null && maybeParent.id() != comprehensionExpr.id()) {
 if (maybeParent.getKind().equals(Kind.COMPREHENSION)) {
 if (maybeParent.getKind().equals(ExprKind.Kind.COMPREHENSION)) {
 nestedLevel++;
 }
 maybeParent = maybeParent.parent().orElse(null);
Expand DownExpand Up@@ -552,6 +555,151 @@ public CelMutableAst replaceSubtree(
 return CelMutableAst.of(mutatedRoot, newAstSource);
 }

 /**
 * Replaces a subtree in the given AST with the specified {@link SubtreeReplacement}.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes. The renumbering occurs even if the subtree was not replaced.
 *
 * @param ast Original AST to mutate.
 * @param replacement Subtree replacement containing the target node ID and the new expression or
 * AST.
 */
 public CelMutableAst replaceSubtree(CelMutableAst ast, SubtreeReplacement replacement) {
 Preconditions.checkNotNull(ast);
 Preconditions.checkNotNull(replacement);
 switch (replacement.replacement().kind()) {
 case EXPR:
 return replaceSubtree(ast, replacement.replacement().expr(), replacement.exprIdToReplace());
 case AST:
 return replaceSubtree(ast, replacement.replacement().ast(), replacement.exprIdToReplace());
 }
 throw new IllegalArgumentException(
 "Unsupported replacement kind: " + replacement.replacement().kind());
 }

 /**
 * Repeatedly applies AST mutations using the provided AST-level rewriter until no further
 * replacements match (fixed point reached) or the mutator's iteration limit is exhausted.
 *
 * <p>Per iteration pass, the AST is traversed to find and perform at most one matching subtree
 * substitution before restarting traversal on the newly mutated AST.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param astRewriter Function returning a {@link SubtreeReplacement} or {@code Optional.empty()}
 * when no further rewrites are possible.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 Function<CelNavigableMutableAst, Optional<SubtreeReplacement>> astRewriter) {
 Preconditions.checkNotNull(ast);
 Preconditions.checkNotNull(astRewriter);
 CelMutableAst mutableAst = ast;
 for (long i = 0; i < iterationLimit; i++) {
 CelNavigableMutableAst navAst = CelNavigableMutableAst.fromAst(mutableAst);
 Optional<SubtreeReplacement> replacement = astRewriter.apply(navAst);
 if (!replacement.isPresent()) {
 return mutableAst;
 }
 mutableAst = replaceSubtree(mutableAst, replacement.get());
 }
 throw new IllegalStateException("Max iteration count reached.");
 }

 /**
 * Traverses nodes using the specified {@link TraversalOrder} and repeatedly rewrites matching
 * subtrees until a fixed point is reached.
 *
 * <p>Per iteration pass, the AST is walked in the given order to find and perform the first
 * matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
 * match or the mutator's iteration limit is exhausted.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param traversalOrder Order in which nodes are visited per iteration pass.
 * @param nodeRewriter Function returning a {@link SubtreeReplacement} or {@code
 * Optional.empty()}.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 TraversalOrder traversalOrder,
 Function<CelNavigableMutableExpr, Optional<SubtreeReplacement>> nodeRewriter) {
 Preconditions.checkNotNull(traversalOrder);
 Preconditions.checkNotNull(nodeRewriter);
 return mutateUntilFixedPoint(
 ast,
 navAst ->
 navAst
 .getRoot()
 .allNodes(traversalOrder)
 .flatMap(node -> Streams.stream(nodeRewriter.apply(node)))
 .findFirst());
 }

 /**
 * Traverses nodes using the specified {@link TraversalOrder}, applies the node matcher, and
 * substitutes matching nodes with the returned replacement expression (targeting {@code
 * node.id()}).
 *
 * <p>Per iteration pass, the AST is walked in the given order to find and perform the first
 * matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
 * match or the mutator's iteration limit is exhausted.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param traversalOrder Order in which nodes are visited per iteration pass.
 * @param nodeMatcher Predicate to filter candidate nodes.
 * @param nodeRewriter Function producing the new {@link CelMutableExpr} for matched nodes.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 TraversalOrder traversalOrder,
 Predicate<CelNavigableMutableExpr> nodeMatcher,
 Function<CelNavigableMutableExpr, Optional<CelMutableExpr>> nodeRewriter) {
 Preconditions.checkNotNull(nodeMatcher);
 Preconditions.checkNotNull(nodeRewriter);
 return mutateUntilFixedPoint(
 ast,
 traversalOrder,
 node ->
 nodeMatcher.test(node)
 ? nodeRewriter.apply(node).map(newExpr -> SubtreeReplacement.of(node.id(), newExpr))
 : Optional.empty());
 }

 private CelMutableExpr mangleIdentsInComprehensionExpr(
 CelMutableExpr root,
 CelMutableExpr comprehensionExpr,
Expand DownExpand Up@@ -590,7 +738,7 @@ private void replaceIdentName(
 .map(CelNavigableMutableExpr::expr)
 .filter(
 node ->
 node.getKind().equals(Kind.IDENT)
 node.getKind().equals(ExprKind.Kind.IDENT)
 && node.ident().name().equals(originalIdentName))
 .findAny()
 .orElse(null);
Expand DownExpand Up@@ -776,7 +924,7 @@ private CelMutableSource normalizeMacroSource(
 long replacedId = idGenerator.generate(exprIdToReplace);
 boolean isListExprBeingReplaced =
 allExprs.containsKey(replacedId)
 && allExprs.get(replacedId).getKind().equals(Kind.LIST);
 && allExprs.get(replacedId).getKind().equals(ExprKind.Kind.LIST);
 if (isListExprBeingReplaced) {
 unwrapListArgumentsInMacroCallExpr(
 allExprs.get(callId).comprehension(), newMacroCallExpr);
Expand All@@ -791,7 +939,7 @@ private CelMutableSource normalizeMacroSource(
 CelMutableExpr macroCallExpr = macroCall.getValue();
 CelNavigableMutableExpr.fromExpr(macroCallExpr)
 .allNodes()
 .filter(node -> node.getKind().equals(Kind.COMPREHENSION))
 .filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .map(CelNavigableMutableExpr::expr)
 .forEach(
 node -> {
Expand All@@ -808,7 +956,7 @@ private CelMutableSource normalizeMacroSource(
 // This can occur from pulling out a nested comprehension into a separate cel.block index
 CelNavigableMutableExpr.fromExpr(macroCallExpr)
 .allNodes()
 .filter(node -> node.getKind().equals(Kind.NOT_SET))
 .filter(node -> node.getKind().equals(ExprKind.Kind.NOT_SET))
 .map(CelNavigableMutableExpr::id)
 .filter(id -> !allExprs.containsKey(id))
 .forEach(
Expand DownExpand Up@@ -840,7 +988,7 @@ private CelMutableSource normalizeMacroSource(
 private static void unwrapListArgumentsInMacroCallExpr(
 CelMutableComprehension comprehension, CelMutableExpr newMacroCallExpr) {
 CelMutableExpr accuInit = comprehension.accuInit();
 if (!accuInit.getKind().equals(Kind.LIST) || !accuInit.list().elements().isEmpty()) {
 if (!accuInit.getKind().equals(ExprKind.Kind.LIST) || !accuInit.list().elements().isEmpty()) {
 // Does not contain an extraneous list.
 return;
 }
Expand DownExpand Up@@ -983,4 +1131,53 @@ private static MangledComprehensionName of(
 iterVarName, iterVar2Name, resultName);
 }
 }

 /**
 * Represents a planned subtree replacement containing the target node ID to replace and either a
 * {@link CelMutableExpr} or {@link CelMutableAst}.
 */
 @AutoValue
 public abstract static class SubtreeReplacement {

 public abstract long exprIdToReplace();

 public abstract Replacement replacement();

 public static SubtreeReplacement of(long exprIdToReplace, CelMutableExpr replacementExpr) {
 return new AutoValue_AstMutator_SubtreeReplacement(
 exprIdToReplace, Replacement.ofExpr(replacementExpr));
 }

 public static SubtreeReplacement of(long exprIdToReplace, CelMutableAst replacementAst) {
 return new AutoValue_AstMutator_SubtreeReplacement(
 exprIdToReplace, Replacement.ofAst(replacementAst));
 }

 /** Discriminated union of either a {@link CelMutableExpr} or a {@link CelMutableAst}. */
 @AutoOneOf(Replacement.Kind.class)
 public abstract static class Replacement {

 public abstract CelMutableExpr expr();

 public abstract CelMutableAst ast();

 public abstract Replacement.Kind kind();

 public static Replacement ofExpr(CelMutableExpr expr) {
 return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.expr(
 Preconditions.checkNotNull(expr));
 }

 public static Replacement ofAst(CelMutableAst ast) {
 return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.ast(
 Preconditions.checkNotNull(ast));
 }

 /** Kind of {@link Replacement}. */
 public enum Kind {
 EXPR,
 AST
 }
 }
 }
}

1 change: 1 addition & 0 deletions
optimizer/src/main/java/dev/cel/optimizer/optimizers/BUILD.bazel

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -96,6 +96,7 @@ java_library(
 "//common:operator",
 "//common/ast",
 "//common/ast:mutable_expr",
 "//common/navigation:common",
 "//common/navigation:expr_util",
 "//common/navigation:mutable_navigation",
 "//common/types",
Expand Down
Loading
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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Aug 10, 2026
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Add helpers for performing fixed point optimization
#1176
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221 changes: 209 additions & 12 deletions
optimizer/src/main/java/dev/cel/optimizer/AstMutator.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -18,17 +18,19 @@
import static java.lang.Math.max;
import static java.util.stream.Collectors.toCollection;

import com.google.auto.value.AutoOneOf;
import com.google.auto.value.AutoValue;
import com.google.common.base.Preconditions;
import com.google.common.base.Strings;
import com.google.common.collect.HashBasedTable;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Streams;
import com.google.common.collect.Table;
import com.google.errorprone.annotations.Immutable;
import dev.cel.common.CelAbstractSyntaxTree;
import dev.cel.common.CelMutableAst;
import dev.cel.common.CelMutableSource;
import dev.cel.common.ast.CelExpr.ExprKind.Kind;
import dev.cel.common.ast.CelExpr.ExprKind;
import dev.cel.common.ast.CelExprIdGeneratorFactory;
import dev.cel.common.ast.CelExprIdGeneratorFactory.ExprIdGenerator;
import dev.cel.common.ast.CelExprIdGeneratorFactory.StableIdGenerator;
Expand All@@ -49,6 +51,7 @@
import java.util.Map.Entry;
import java.util.NoSuchElementException;
import java.util.Optional;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Collectors;

Expand DownExpand Up@@ -213,7 +216,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 Predicate<CelNavigableMutableExpr> comprehensionIdentifierPredicate = x -> true;
 comprehensionIdentifierPredicate =
 comprehensionIdentifierPredicate
 .and(node -> node.getKind().equals(Kind.COMPREHENSION))
 .and(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .and(node -> !node.expr().comprehension().iterVar().startsWith(newIterVarPrefix + ":"))
 .and(node -> !node.expr().comprehension().accuVar().startsWith(newAccuVarPrefix + ":"))
 .and(
Expand All@@ -235,7 +238,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 String result = node.expr().comprehension().result().ident().name();
 return CelNavigableMutableExpr.fromExpr(node.expr().comprehension().loopStep())
 .allNodes()
 .filter(subNode -> subNode.getKind().equals(Kind.IDENT))
 .filter(subNode -> subNode.getKind().equals(ExprKind.Kind.IDENT))
 .map(subNode -> subNode.expr().ident())
 .anyMatch(
 ident ->
Expand All@@ -259,7 +262,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 .allNodes()
 .filter(
 loopStepNode ->
 loopStepNode.getKind().equals(Kind.IDENT)
 loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
 && loopStepNode.expr().ident().name().equals(iterVar))
 .map(CelNavigableMutableExpr::id)
 .findAny();
Expand All@@ -269,7 +272,7 @@ public MangledComprehensionAst mangleComprehensionIdentifierNames(
 .filter(
 loopStepNode ->
 !iterVar2.isEmpty()
 && loopStepNode.getKind().equals(Kind.IDENT)
 && loopStepNode.getKind().equals(ExprKind.Kind.IDENT)
 && loopStepNode.expr().ident().name().equals(iterVar2))
 .map(CelNavigableMutableExpr::id)
 .findAny();
Expand DownExpand Up@@ -406,13 +409,13 @@ private static MangledComprehensionName getMangledComprehensionName(
 private static int countComprehensionNestingLevel(CelNavigableMutableExpr comprehensionExpr) {
 return comprehensionExpr
 .descendants()
 .filter(node -> node.getKind().equals(Kind.COMPREHENSION))
 .filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .mapToInt(
 node -> {
 int nestedLevel = 1;
 CelNavigableMutableExpr maybeParent = node.parent().orElse(null);
 while (maybeParent != null && maybeParent.id() != comprehensionExpr.id()) {
 if (maybeParent.getKind().equals(Kind.COMPREHENSION)) {
 if (maybeParent.getKind().equals(ExprKind.Kind.COMPREHENSION)) {
 nestedLevel++;
 }
 maybeParent = maybeParent.parent().orElse(null);
Expand DownExpand Up@@ -552,6 +555,151 @@ public CelMutableAst replaceSubtree(
 return CelMutableAst.of(mutatedRoot, newAstSource);
 }

 /**
 * Replaces a subtree in the given AST with the specified {@link SubtreeReplacement}.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes. The renumbering occurs even if the subtree was not replaced.
 *
 * @param ast Original AST to mutate.
 * @param replacement Subtree replacement containing the target node ID and the new expression or
 * AST.
 */
 public CelMutableAst replaceSubtree(CelMutableAst ast, SubtreeReplacement replacement) {
 Preconditions.checkNotNull(ast);
 Preconditions.checkNotNull(replacement);
 switch (replacement.replacement().kind()) {
 case EXPR:
 return replaceSubtree(ast, replacement.replacement().expr(), replacement.exprIdToReplace());
 case AST:
 return replaceSubtree(ast, replacement.replacement().ast(), replacement.exprIdToReplace());
 }
 throw new IllegalArgumentException(
 "Unsupported replacement kind: " + replacement.replacement().kind());
 }

 /**
 * Repeatedly applies AST mutations using the provided AST-level rewriter until no further
 * replacements match (fixed point reached) or the mutator's iteration limit is exhausted.
 *
 * <p>Per iteration pass, the AST is traversed to find and perform at most one matching subtree
 * substitution before restarting traversal on the newly mutated AST.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param astRewriter Function returning a {@link SubtreeReplacement} or {@code Optional.empty()}
 * when no further rewrites are possible.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 Function<CelNavigableMutableAst, Optional<SubtreeReplacement>> astRewriter) {
 Preconditions.checkNotNull(ast);
 Preconditions.checkNotNull(astRewriter);
 CelMutableAst mutableAst = ast;
 for (long i = 0; i < iterationLimit; i++) {
 CelNavigableMutableAst navAst = CelNavigableMutableAst.fromAst(mutableAst);
 Optional<SubtreeReplacement> replacement = astRewriter.apply(navAst);
 if (!replacement.isPresent()) {
 return mutableAst;
 }
 mutableAst = replaceSubtree(mutableAst, replacement.get());
 }
 throw new IllegalStateException("Max iteration count reached.");
 }

 /**
 * Traverses nodes using the specified {@link TraversalOrder} and repeatedly rewrites matching
 * subtrees until a fixed point is reached.
 *
 * <p>Per iteration pass, the AST is walked in the given order to find and perform the first
 * matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
 * match or the mutator's iteration limit is exhausted.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param traversalOrder Order in which nodes are visited per iteration pass.
 * @param nodeRewriter Function returning a {@link SubtreeReplacement} or {@code
 * Optional.empty()}.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 TraversalOrder traversalOrder,
 Function<CelNavigableMutableExpr, Optional<SubtreeReplacement>> nodeRewriter) {
 Preconditions.checkNotNull(traversalOrder);
 Preconditions.checkNotNull(nodeRewriter);
 return mutateUntilFixedPoint(
 ast,
 navAst ->
 navAst
 .getRoot()
 .allNodes(traversalOrder)
 .flatMap(node -> Streams.stream(nodeRewriter.apply(node)))
 .findFirst());
 }

 /**
 * Traverses nodes using the specified {@link TraversalOrder}, applies the node matcher, and
 * substitutes matching nodes with the returned replacement expression (targeting {@code
 * node.id()}).
 *
 * <p>Per iteration pass, the AST is walked in the given order to find and perform the first
 * matching substitution. The traversal then restarts on the freshly mutated AST until no nodes
 * match or the mutator's iteration limit is exhausted.
 *
 * <p>This operation is intended for AST optimization purposes.
 *
 * <p>This is a very dangerous operation. Callers must re-typecheck the mutated AST and
 * additionally verify that the resulting AST is semantically valid.
 *
 * <p>All expression IDs will be renumbered in a stable manner to ensure there's no ID collision
 * between the nodes.
 *
 * @param ast Initial mutable AST to mutate.
 * @param traversalOrder Order in which nodes are visited per iteration pass.
 * @param nodeMatcher Predicate to filter candidate nodes.
 * @param nodeRewriter Function producing the new {@link CelMutableExpr} for matched nodes.
 * @return Mutated {@link CelMutableAst} at fixed point.
 * @throws IllegalStateException If the iteration count exceeds {@code iterationLimit}.
 */
 public CelMutableAst mutateUntilFixedPoint(
 CelMutableAst ast,
 TraversalOrder traversalOrder,
 Predicate<CelNavigableMutableExpr> nodeMatcher,
 Function<CelNavigableMutableExpr, Optional<CelMutableExpr>> nodeRewriter) {
 Preconditions.checkNotNull(nodeMatcher);
 Preconditions.checkNotNull(nodeRewriter);
 return mutateUntilFixedPoint(
 ast,
 traversalOrder,
 node ->
 nodeMatcher.test(node)
 ? nodeRewriter.apply(node).map(newExpr -> SubtreeReplacement.of(node.id(), newExpr))
 : Optional.empty());
 }

 private CelMutableExpr mangleIdentsInComprehensionExpr(
 CelMutableExpr root,
 CelMutableExpr comprehensionExpr,
Expand DownExpand Up@@ -590,7 +738,7 @@ private void replaceIdentName(
 .map(CelNavigableMutableExpr::expr)
 .filter(
 node ->
 node.getKind().equals(Kind.IDENT)
 node.getKind().equals(ExprKind.Kind.IDENT)
 && node.ident().name().equals(originalIdentName))
 .findAny()
 .orElse(null);
Expand DownExpand Up@@ -776,7 +924,7 @@ private CelMutableSource normalizeMacroSource(
 long replacedId = idGenerator.generate(exprIdToReplace);
 boolean isListExprBeingReplaced =
 allExprs.containsKey(replacedId)
 && allExprs.get(replacedId).getKind().equals(Kind.LIST);
 && allExprs.get(replacedId).getKind().equals(ExprKind.Kind.LIST);
 if (isListExprBeingReplaced) {
 unwrapListArgumentsInMacroCallExpr(
 allExprs.get(callId).comprehension(), newMacroCallExpr);
Expand All@@ -791,7 +939,7 @@ private CelMutableSource normalizeMacroSource(
 CelMutableExpr macroCallExpr = macroCall.getValue();
 CelNavigableMutableExpr.fromExpr(macroCallExpr)
 .allNodes()
 .filter(node -> node.getKind().equals(Kind.COMPREHENSION))
 .filter(node -> node.getKind().equals(ExprKind.Kind.COMPREHENSION))
 .map(CelNavigableMutableExpr::expr)
 .forEach(
 node -> {
Expand All@@ -808,7 +956,7 @@ private CelMutableSource normalizeMacroSource(
 // This can occur from pulling out a nested comprehension into a separate cel.block index
 CelNavigableMutableExpr.fromExpr(macroCallExpr)
 .allNodes()
 .filter(node -> node.getKind().equals(Kind.NOT_SET))
 .filter(node -> node.getKind().equals(ExprKind.Kind.NOT_SET))
 .map(CelNavigableMutableExpr::id)
 .filter(id -> !allExprs.containsKey(id))
 .forEach(
Expand DownExpand Up@@ -840,7 +988,7 @@ private CelMutableSource normalizeMacroSource(
 private static void unwrapListArgumentsInMacroCallExpr(
 CelMutableComprehension comprehension, CelMutableExpr newMacroCallExpr) {
 CelMutableExpr accuInit = comprehension.accuInit();
 if (!accuInit.getKind().equals(Kind.LIST) || !accuInit.list().elements().isEmpty()) {
 if (!accuInit.getKind().equals(ExprKind.Kind.LIST) || !accuInit.list().elements().isEmpty()) {
 // Does not contain an extraneous list.
 return;
 }
Expand DownExpand Up@@ -983,4 +1131,53 @@ private static MangledComprehensionName of(
 iterVarName, iterVar2Name, resultName);
 }
 }

 /**
 * Represents a planned subtree replacement containing the target node ID to replace and either a
 * {@link CelMutableExpr} or {@link CelMutableAst}.
 */
 @AutoValue
 public abstract static class SubtreeReplacement {

 public abstract long exprIdToReplace();

 public abstract Replacement replacement();

 public static SubtreeReplacement of(long exprIdToReplace, CelMutableExpr replacementExpr) {
 return new AutoValue_AstMutator_SubtreeReplacement(
 exprIdToReplace, Replacement.ofExpr(replacementExpr));
 }

 public static SubtreeReplacement of(long exprIdToReplace, CelMutableAst replacementAst) {
 return new AutoValue_AstMutator_SubtreeReplacement(
 exprIdToReplace, Replacement.ofAst(replacementAst));
 }

 /** Discriminated union of either a {@link CelMutableExpr} or a {@link CelMutableAst}. */
 @AutoOneOf(Replacement.Kind.class)
 public abstract static class Replacement {

 public abstract CelMutableExpr expr();

 public abstract CelMutableAst ast();

 public abstract Replacement.Kind kind();

 public static Replacement ofExpr(CelMutableExpr expr) {
 return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.expr(
 Preconditions.checkNotNull(expr));
 }

 public static Replacement ofAst(CelMutableAst ast) {
 return AutoOneOf_AstMutator_SubtreeReplacement_Replacement.ast(
 Preconditions.checkNotNull(ast));
 }

 /** Kind of {@link Replacement}. */
 public enum Kind {
 EXPR,
 AST
 }
 }
 }
}

1 change: 1 addition & 0 deletions
optimizer/src/main/java/dev/cel/optimizer/optimizers/BUILD.bazel

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -96,6 +96,7 @@ java_library(
 "//common:operator",
 "//common/ast",
 "//common/ast:mutable_expr",
 "//common/navigation:common",
 "//common/navigation:expr_util",
 "//common/navigation:mutable_navigation",
 "//common/types",
Expand Down
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