[Wasm RyuJit] Control flow codegen

[AndyAyersMS]

Emit plausible Wasm control flow for blocks during genCodeForBBList.

Also add a bit of support for relop codegen, so blocks ending in branches have something to use.

Contributes to #121178.

[Copilot]

Pull request overview

This PR implements WebAssembly control flow code generation during the genCodeForBBList phase, enabling the JIT to emit structured control flow for Wasm blocks, loops, and branches. The implementation includes basic relational operator (relop) support for conditional branches.

Key changes include:

• Addition of Wasm control flow and relational operation instructions to the instruction table
• Movement of WasmInterval class from fgwasm.cpp to fgwasm.h for use during code generation
• Integration of the Wasm control flow transformation phases into the compilation pipeline (non-DEBUG builds)
• Implementation of control flow instruction emission in genCodeForBBlist, including block/loop/end nesting and branch depth calculation
• Basic GT_GT (greater than) relational operator codegen support

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
instrswasm.h	Adds Wasm control flow instructions (block, loop, if, else, end, br, br_if, br_table, return) and relational operators (eqz, eq, ne, lt, gt, le, ge for i32, i64, f32, f64 types)
fgwasm.h	Moves WasmInterval class definition from .cpp to header for codegen access
fgwasm.cpp	Moves WasmInterval to header, adds block reordering with branch condition reversal, adds debug dump functions, removes debug-only control flow simulation code
jitconfigvalues.h	Removes JitWasmControlFlow debug config option (now enabled for TARGET_WASM)
compiler.h	Adds WasmInterval forward declaration and fgWasmIntervals field to store control flow intervals for codegen
compiler.cpp	Moves Wasm SCC transformation and control flow phases from DEBUG-only to TARGET_WASM builds, repositions them in compilation pipeline
lowerwasm.cpp	Implements LowerJTrue to defer branch handling to codegen instead of using NYI
emitwasm.h	Adds code_t typedef for instruction opcodes
emitwasm.cpp	Implements insOpcode lookup, emitOutputInstr for IF_OPCODE/IF_ULEB128 formats, emitJumpKindToIns mapping, placeholder getInsExecutionCharacteristics
emitjmps.h	Defines Wasm jump kinds: br, br_if, br_table
codegenwasm.cpp	Implements genFnProlog, adds GT_GT to tree node codegen, implements inst_JMP/inst_LABEL for Wasm depth-based branching
codegen.h	Adds Wasm-specific inst_JMP and inst_LABEL declarations taking depth parameter
codegenlinear.cpp	Adds Wasm control flow stack management, emits block/loop/end instructions around blocks, generates Wasm branches (br, br_if, br_table) at block ends with depth calculation
CMakeLists.txt	Moves fgwasm.cpp from common JIT sources to TARGET_WASM-specific sources

[AndyAyersMS]

FYI @dotnet/jit-contrib @SingleAccretion

This won't get much testing in CI... locally it lets us get a simple method like

intFoo(inta,intb){if(a>b)returnb;returna;}

through more of codegen. Prolog gen stubbed out for now.

=============== Generating BB01 [0000] [000..004) -> BB02(0.5),BB03(0.5) (cond), preds={} succs={BB03,BB02} flags=0x00000000.00000011: i LIR
BB01 IN (2)={V00 V01}
OUT(2)={V00 V01}
Change life 0000000000000000 {} -> 0000000000000003 {V00 V01}
Debug: New V00 debug range: first
Debug: New V01 debug range: first
L_M10749_BB01:
Mapped BB01 to G_M10749_IG02
IN0001: block
Scope info: begin block BB01, IL range [000..004)
Added IP mapping: 0x0000 STACK_EMPTY (G_M10749_IG02,ins#1,ofs#1) label
Generating: [000008] ----------- IL_OFFSET void INLRT @ 0x000[E--]
Generating: N001 ( 1, 1) [000000] -----+----- t0 = LCL_VAR int V00 arg0 u:1 $80
IN0002: i32.load 1 4
Generating: N002 ( 1, 1) [000001] -----+----- t1 = LCL_VAR int V01 arg1 u:1 $81
IN0003: i32.load 1 0
/--* t0 int +--* t1 int Generating: N003 ( 3, 3) [000002] J----+-N--- t2 = * GT int IN0004: i32.gt_s
/--* t2 int Generating: N004 ( 5, 5) [000003] -----+----- * JTRUE void $VN.Void
IN0005: br_if 0
...

Also addresses a few bits of @jakobbotsch's feedback on #121728. The SCC phase is moved later, some debug only stuff is now really debug only, etc.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[AndyAyersMS]

With the latest commit, we can alt-jit methods that just return. Lots of stuff still incomplete, but we have a lot we can fill in now.

[AndyAyersMS]

@SingleAccretion think I got most of your feedback, except leaving LABEL as is for now. Wasn't sure what you were commenting on for the prolog.

Please take another look.

[SingleAccretion]

Thank you for addressing the feedback, it looks much nicer now! I've left a few comments.

[AndyAyersMS]

@SingleAccretion thanks again, pushed another update

[SingleAccretion]

LGTM modulo the genFnProlog comment (#121973 (comment)) and one suggestion.

[AndyAyersMS]

@dotnet/jit-contrib ping

[AndyAyersMS]

@jakobbotsch now using a common genEmitEndBlock.
@adamperlin any other notes you want to add?

[jakobbotsch]

Looks great to me now.

[AndyAyersMS]

Not easy to get Roslyn to emit an actual switch, but here's an example of one making it to codegen (requires some fixes/workarounds not in this PR)

[adamperlin]

This looks good to me! I don't have any notes I wanted to add at the moment!

[AndyAyersMS]

Emit plausible Wasm control flow for blocks during genCodeForBBList.

Also add a bit of support for relop codegen, so blocks ending in branches have something to use.

Contributes to #121178.

[Copilot]

Pull request overview

This PR implements WebAssembly control flow code generation during the genCodeForBBList phase, enabling the JIT to emit structured control flow for Wasm blocks, loops, and branches. The implementation includes basic relational operator (relop) support for conditional branches.

Key changes include:

• Addition of Wasm control flow and relational operation instructions to the instruction table
• Movement of WasmInterval class from fgwasm.cpp to fgwasm.h for use during code generation
• Integration of the Wasm control flow transformation phases into the compilation pipeline (non-DEBUG builds)
• Implementation of control flow instruction emission in genCodeForBBlist, including block/loop/end nesting and branch depth calculation
• Basic GT_GT (greater than) relational operator codegen support

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
instrswasm.h	Adds Wasm control flow instructions (block, loop, if, else, end, br, br_if, br_table, return) and relational operators (eqz, eq, ne, lt, gt, le, ge for i32, i64, f32, f64 types)
fgwasm.h	Moves WasmInterval class definition from .cpp to header for codegen access
fgwasm.cpp	Moves WasmInterval to header, adds block reordering with branch condition reversal, adds debug dump functions, removes debug-only control flow simulation code
jitconfigvalues.h	Removes JitWasmControlFlow debug config option (now enabled for TARGET_WASM)
compiler.h	Adds WasmInterval forward declaration and fgWasmIntervals field to store control flow intervals for codegen
compiler.cpp	Moves Wasm SCC transformation and control flow phases from DEBUG-only to TARGET_WASM builds, repositions them in compilation pipeline
lowerwasm.cpp	Implements LowerJTrue to defer branch handling to codegen instead of using NYI
emitwasm.h	Adds code_t typedef for instruction opcodes
emitwasm.cpp	Implements insOpcode lookup, emitOutputInstr for IF_OPCODE/IF_ULEB128 formats, emitJumpKindToIns mapping, placeholder getInsExecutionCharacteristics
emitjmps.h	Defines Wasm jump kinds: br, br_if, br_table
codegenwasm.cpp	Implements genFnProlog, adds GT_GT to tree node codegen, implements inst_JMP/inst_LABEL for Wasm depth-based branching
codegen.h	Adds Wasm-specific inst_JMP and inst_LABEL declarations taking depth parameter
codegenlinear.cpp	Adds Wasm control flow stack management, emits block/loop/end instructions around blocks, generates Wasm branches (br, br_if, br_table) at block ends with depth calculation
CMakeLists.txt	Moves fgwasm.cpp from common JIT sources to TARGET_WASM-specific sources

[AndyAyersMS]

FYI @dotnet/jit-contrib @SingleAccretion

This won't get much testing in CI... locally it lets us get a simple method like

intFoo(inta,intb){if(a>b)returnb;returna;}

through more of codegen. Prolog gen stubbed out for now.

=============== Generating BB01 [0000] [000..004) -> BB02(0.5),BB03(0.5) (cond), preds={} succs={BB03,BB02} flags=0x00000000.00000011: i LIR
BB01 IN (2)={V00 V01}
OUT(2)={V00 V01}
Change life 0000000000000000 {} -> 0000000000000003 {V00 V01}
Debug: New V00 debug range: first
Debug: New V01 debug range: first
L_M10749_BB01:
Mapped BB01 to G_M10749_IG02
IN0001: block
Scope info: begin block BB01, IL range [000..004)
Added IP mapping: 0x0000 STACK_EMPTY (G_M10749_IG02,ins#1,ofs#1) label
Generating: [000008] ----------- IL_OFFSET void INLRT @ 0x000[E--]
Generating: N001 ( 1, 1) [000000] -----+----- t0 = LCL_VAR int V00 arg0 u:1 $80
IN0002: i32.load 1 4
Generating: N002 ( 1, 1) [000001] -----+----- t1 = LCL_VAR int V01 arg1 u:1 $81
IN0003: i32.load 1 0
/--* t0 int +--* t1 int Generating: N003 ( 3, 3) [000002] J----+-N--- t2 = * GT int IN0004: i32.gt_s
/--* t2 int Generating: N004 ( 5, 5) [000003] -----+----- * JTRUE void $VN.Void
IN0005: br_if 0
...

Also addresses a few bits of @jakobbotsch's feedback on #121728. The SCC phase is moved later, some debug only stuff is now really debug only, etc.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[AndyAyersMS]

With the latest commit, we can alt-jit methods that just return. Lots of stuff still incomplete, but we have a lot we can fill in now.

[AndyAyersMS]

@SingleAccretion think I got most of your feedback, except leaving LABEL as is for now. Wasn't sure what you were commenting on for the prolog.

Please take another look.

[SingleAccretion]

Thank you for addressing the feedback, it looks much nicer now! I've left a few comments.

[AndyAyersMS]

@SingleAccretion thanks again, pushed another update

[SingleAccretion]

LGTM modulo the genFnProlog comment (#121973 (comment)) and one suggestion.

[AndyAyersMS]

@dotnet/jit-contrib ping

[AndyAyersMS]

@jakobbotsch now using a common genEmitEndBlock.
@adamperlin any other notes you want to add?

[jakobbotsch]

Looks great to me now.

[AndyAyersMS]

Not easy to get Roslyn to emit an actual switch, but here's an example of one making it to codegen (requires some fixes/workarounds not in this PR)

[adamperlin]

This looks good to me! I don't have any notes I wanted to add at the moment!

[AndyAyersMS]

Emit plausible Wasm control flow for blocks during genCodeForBBList.

Also add a bit of support for relop codegen, so blocks ending in branches have something to use.

Contributes to #121178.

[Copilot]

Pull request overview

This PR implements WebAssembly control flow code generation during the genCodeForBBList phase, enabling the JIT to emit structured control flow for Wasm blocks, loops, and branches. The implementation includes basic relational operator (relop) support for conditional branches.

Key changes include:

• Addition of Wasm control flow and relational operation instructions to the instruction table
• Movement of WasmInterval class from fgwasm.cpp to fgwasm.h for use during code generation
• Integration of the Wasm control flow transformation phases into the compilation pipeline (non-DEBUG builds)
• Implementation of control flow instruction emission in genCodeForBBlist, including block/loop/end nesting and branch depth calculation
• Basic GT_GT (greater than) relational operator codegen support

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
instrswasm.h	Adds Wasm control flow instructions (block, loop, if, else, end, br, br_if, br_table, return) and relational operators (eqz, eq, ne, lt, gt, le, ge for i32, i64, f32, f64 types)
fgwasm.h	Moves WasmInterval class definition from .cpp to header for codegen access
fgwasm.cpp	Moves WasmInterval to header, adds block reordering with branch condition reversal, adds debug dump functions, removes debug-only control flow simulation code
jitconfigvalues.h	Removes JitWasmControlFlow debug config option (now enabled for TARGET_WASM)
compiler.h	Adds WasmInterval forward declaration and fgWasmIntervals field to store control flow intervals for codegen
compiler.cpp	Moves Wasm SCC transformation and control flow phases from DEBUG-only to TARGET_WASM builds, repositions them in compilation pipeline
lowerwasm.cpp	Implements LowerJTrue to defer branch handling to codegen instead of using NYI
emitwasm.h	Adds code_t typedef for instruction opcodes
emitwasm.cpp	Implements insOpcode lookup, emitOutputInstr for IF_OPCODE/IF_ULEB128 formats, emitJumpKindToIns mapping, placeholder getInsExecutionCharacteristics
emitjmps.h	Defines Wasm jump kinds: br, br_if, br_table
codegenwasm.cpp	Implements genFnProlog, adds GT_GT to tree node codegen, implements inst_JMP/inst_LABEL for Wasm depth-based branching
codegen.h	Adds Wasm-specific inst_JMP and inst_LABEL declarations taking depth parameter
codegenlinear.cpp	Adds Wasm control flow stack management, emits block/loop/end instructions around blocks, generates Wasm branches (br, br_if, br_table) at block ends with depth calculation
CMakeLists.txt	Moves fgwasm.cpp from common JIT sources to TARGET_WASM-specific sources

[AndyAyersMS]

FYI @dotnet/jit-contrib @SingleAccretion

This won't get much testing in CI... locally it lets us get a simple method like

intFoo(inta,intb){if(a>b)returnb;returna;}

through more of codegen. Prolog gen stubbed out for now.

=============== Generating BB01 [0000] [000..004) -> BB02(0.5),BB03(0.5) (cond), preds={} succs={BB03,BB02} flags=0x00000000.00000011: i LIR
BB01 IN (2)={V00 V01}
OUT(2)={V00 V01}
Change life 0000000000000000 {} -> 0000000000000003 {V00 V01}
Debug: New V00 debug range: first
Debug: New V01 debug range: first
L_M10749_BB01:
Mapped BB01 to G_M10749_IG02
IN0001: block
Scope info: begin block BB01, IL range [000..004)
Added IP mapping: 0x0000 STACK_EMPTY (G_M10749_IG02,ins#1,ofs#1) label
Generating: [000008] ----------- IL_OFFSET void INLRT @ 0x000[E--]
Generating: N001 ( 1, 1) [000000] -----+----- t0 = LCL_VAR int V00 arg0 u:1 $80
IN0002: i32.load 1 4
Generating: N002 ( 1, 1) [000001] -----+----- t1 = LCL_VAR int V01 arg1 u:1 $81
IN0003: i32.load 1 0
/--* t0 int +--* t1 int Generating: N003 ( 3, 3) [000002] J----+-N--- t2 = * GT int IN0004: i32.gt_s
/--* t2 int Generating: N004 ( 5, 5) [000003] -----+----- * JTRUE void $VN.Void
IN0005: br_if 0
...

Also addresses a few bits of @jakobbotsch's feedback on #121728. The SCC phase is moved later, some debug only stuff is now really debug only, etc.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[AndyAyersMS]

With the latest commit, we can alt-jit methods that just return. Lots of stuff still incomplete, but we have a lot we can fill in now.

[AndyAyersMS]

@SingleAccretion think I got most of your feedback, except leaving LABEL as is for now. Wasn't sure what you were commenting on for the prolog.

Please take another look.

[SingleAccretion]

Thank you for addressing the feedback, it looks much nicer now! I've left a few comments.

[AndyAyersMS]

@SingleAccretion thanks again, pushed another update

[SingleAccretion]

LGTM modulo the genFnProlog comment (#121973 (comment)) and one suggestion.

[AndyAyersMS]

@dotnet/jit-contrib ping

[AndyAyersMS]

@jakobbotsch now using a common genEmitEndBlock.
@adamperlin any other notes you want to add?

[jakobbotsch]

Looks great to me now.

[AndyAyersMS]

Not easy to get Roslyn to emit an actual switch, but here's an example of one making it to codegen (requires some fixes/workarounds not in this PR)

[adamperlin]

This looks good to me! I don't have any notes I wanted to add at the moment!

[AndyAyersMS]

Emit plausible Wasm control flow for blocks during genCodeForBBList.

Also add a bit of support for relop codegen, so blocks ending in branches have something to use.

Contributes to #121178.

[Copilot]

Pull request overview

This PR implements WebAssembly control flow code generation during the genCodeForBBList phase, enabling the JIT to emit structured control flow for Wasm blocks, loops, and branches. The implementation includes basic relational operator (relop) support for conditional branches.

Key changes include:

• Addition of Wasm control flow and relational operation instructions to the instruction table
• Movement of WasmInterval class from fgwasm.cpp to fgwasm.h for use during code generation
• Integration of the Wasm control flow transformation phases into the compilation pipeline (non-DEBUG builds)
• Implementation of control flow instruction emission in genCodeForBBlist, including block/loop/end nesting and branch depth calculation
• Basic GT_GT (greater than) relational operator codegen support

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
instrswasm.h	Adds Wasm control flow instructions (block, loop, if, else, end, br, br_if, br_table, return) and relational operators (eqz, eq, ne, lt, gt, le, ge for i32, i64, f32, f64 types)
fgwasm.h	Moves WasmInterval class definition from .cpp to header for codegen access
fgwasm.cpp	Moves WasmInterval to header, adds block reordering with branch condition reversal, adds debug dump functions, removes debug-only control flow simulation code
jitconfigvalues.h	Removes JitWasmControlFlow debug config option (now enabled for TARGET_WASM)
compiler.h	Adds WasmInterval forward declaration and fgWasmIntervals field to store control flow intervals for codegen
compiler.cpp	Moves Wasm SCC transformation and control flow phases from DEBUG-only to TARGET_WASM builds, repositions them in compilation pipeline
lowerwasm.cpp	Implements LowerJTrue to defer branch handling to codegen instead of using NYI
emitwasm.h	Adds code_t typedef for instruction opcodes
emitwasm.cpp	Implements insOpcode lookup, emitOutputInstr for IF_OPCODE/IF_ULEB128 formats, emitJumpKindToIns mapping, placeholder getInsExecutionCharacteristics
emitjmps.h	Defines Wasm jump kinds: br, br_if, br_table
codegenwasm.cpp	Implements genFnProlog, adds GT_GT to tree node codegen, implements inst_JMP/inst_LABEL for Wasm depth-based branching
codegen.h	Adds Wasm-specific inst_JMP and inst_LABEL declarations taking depth parameter
codegenlinear.cpp	Adds Wasm control flow stack management, emits block/loop/end instructions around blocks, generates Wasm branches (br, br_if, br_table) at block ends with depth calculation
CMakeLists.txt	Moves fgwasm.cpp from common JIT sources to TARGET_WASM-specific sources

[AndyAyersMS]

FYI @dotnet/jit-contrib @SingleAccretion

This won't get much testing in CI... locally it lets us get a simple method like

intFoo(inta,intb){if(a>b)returnb;returna;}

through more of codegen. Prolog gen stubbed out for now.

=============== Generating BB01 [0000] [000..004) -> BB02(0.5),BB03(0.5) (cond), preds={} succs={BB03,BB02} flags=0x00000000.00000011: i LIR
BB01 IN (2)={V00 V01}
OUT(2)={V00 V01}
Change life 0000000000000000 {} -> 0000000000000003 {V00 V01}
Debug: New V00 debug range: first
Debug: New V01 debug range: first
L_M10749_BB01:
Mapped BB01 to G_M10749_IG02
IN0001: block
Scope info: begin block BB01, IL range [000..004)
Added IP mapping: 0x0000 STACK_EMPTY (G_M10749_IG02,ins#1,ofs#1) label
Generating: [000008] ----------- IL_OFFSET void INLRT @ 0x000[E--]
Generating: N001 ( 1, 1) [000000] -----+----- t0 = LCL_VAR int V00 arg0 u:1 $80
IN0002: i32.load 1 4
Generating: N002 ( 1, 1) [000001] -----+----- t1 = LCL_VAR int V01 arg1 u:1 $81
IN0003: i32.load 1 0
/--* t0 int +--* t1 int Generating: N003 ( 3, 3) [000002] J----+-N--- t2 = * GT int IN0004: i32.gt_s
/--* t2 int Generating: N004 ( 5, 5) [000003] -----+----- * JTRUE void $VN.Void
IN0005: br_if 0
...

Also addresses a few bits of @jakobbotsch's feedback on #121728. The SCC phase is moved later, some debug only stuff is now really debug only, etc.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[AndyAyersMS]

With the latest commit, we can alt-jit methods that just return. Lots of stuff still incomplete, but we have a lot we can fill in now.

[AndyAyersMS]

@SingleAccretion think I got most of your feedback, except leaving LABEL as is for now. Wasn't sure what you were commenting on for the prolog.

Please take another look.

[SingleAccretion]

Thank you for addressing the feedback, it looks much nicer now! I've left a few comments.

[AndyAyersMS]

@SingleAccretion thanks again, pushed another update

[SingleAccretion]

LGTM modulo the genFnProlog comment (#121973 (comment)) and one suggestion.

[AndyAyersMS]

@dotnet/jit-contrib ping

[AndyAyersMS]

@jakobbotsch now using a common genEmitEndBlock.
@adamperlin any other notes you want to add?

[jakobbotsch]

Looks great to me now.

[AndyAyersMS]

Not easy to get Roslyn to emit an actual switch, but here's an example of one making it to codegen (requires some fixes/workarounds not in this PR)

[adamperlin]

This looks good to me! I don't have any notes I wanted to add at the moment!

[AndyAyersMS]

Emit plausible Wasm control flow for blocks during genCodeForBBList.

Also add a bit of support for relop codegen, so blocks ending in branches have something to use.

Contributes to #121178.

[Copilot]

Pull request overview

This PR implements WebAssembly control flow code generation during the genCodeForBBList phase, enabling the JIT to emit structured control flow for Wasm blocks, loops, and branches. The implementation includes basic relational operator (relop) support for conditional branches.

Key changes include:

• Addition of Wasm control flow and relational operation instructions to the instruction table
• Movement of WasmInterval class from fgwasm.cpp to fgwasm.h for use during code generation
• Integration of the Wasm control flow transformation phases into the compilation pipeline (non-DEBUG builds)
• Implementation of control flow instruction emission in genCodeForBBlist, including block/loop/end nesting and branch depth calculation
• Basic GT_GT (greater than) relational operator codegen support

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
instrswasm.h	Adds Wasm control flow instructions (block, loop, if, else, end, br, br_if, br_table, return) and relational operators (eqz, eq, ne, lt, gt, le, ge for i32, i64, f32, f64 types)
fgwasm.h	Moves WasmInterval class definition from .cpp to header for codegen access
fgwasm.cpp	Moves WasmInterval to header, adds block reordering with branch condition reversal, adds debug dump functions, removes debug-only control flow simulation code
jitconfigvalues.h	Removes JitWasmControlFlow debug config option (now enabled for TARGET_WASM)
compiler.h	Adds WasmInterval forward declaration and fgWasmIntervals field to store control flow intervals for codegen
compiler.cpp	Moves Wasm SCC transformation and control flow phases from DEBUG-only to TARGET_WASM builds, repositions them in compilation pipeline
lowerwasm.cpp	Implements LowerJTrue to defer branch handling to codegen instead of using NYI
emitwasm.h	Adds code_t typedef for instruction opcodes
emitwasm.cpp	Implements insOpcode lookup, emitOutputInstr for IF_OPCODE/IF_ULEB128 formats, emitJumpKindToIns mapping, placeholder getInsExecutionCharacteristics
emitjmps.h	Defines Wasm jump kinds: br, br_if, br_table
codegenwasm.cpp	Implements genFnProlog, adds GT_GT to tree node codegen, implements inst_JMP/inst_LABEL for Wasm depth-based branching
codegen.h	Adds Wasm-specific inst_JMP and inst_LABEL declarations taking depth parameter
codegenlinear.cpp	Adds Wasm control flow stack management, emits block/loop/end instructions around blocks, generates Wasm branches (br, br_if, br_table) at block ends with depth calculation
CMakeLists.txt	Moves fgwasm.cpp from common JIT sources to TARGET_WASM-specific sources

[AndyAyersMS]

FYI @dotnet/jit-contrib @SingleAccretion

This won't get much testing in CI... locally it lets us get a simple method like

intFoo(inta,intb){if(a>b)returnb;returna;}

through more of codegen. Prolog gen stubbed out for now.

=============== Generating BB01 [0000] [000..004) -> BB02(0.5),BB03(0.5) (cond), preds={} succs={BB03,BB02} flags=0x00000000.00000011: i LIR
BB01 IN (2)={V00 V01}
OUT(2)={V00 V01}
Change life 0000000000000000 {} -> 0000000000000003 {V00 V01}
Debug: New V00 debug range: first
Debug: New V01 debug range: first
L_M10749_BB01:
Mapped BB01 to G_M10749_IG02
IN0001: block
Scope info: begin block BB01, IL range [000..004)
Added IP mapping: 0x0000 STACK_EMPTY (G_M10749_IG02,ins#1,ofs#1) label
Generating: [000008] ----------- IL_OFFSET void INLRT @ 0x000[E--]
Generating: N001 ( 1, 1) [000000] -----+----- t0 = LCL_VAR int V00 arg0 u:1 $80
IN0002: i32.load 1 4
Generating: N002 ( 1, 1) [000001] -----+----- t1 = LCL_VAR int V01 arg1 u:1 $81
IN0003: i32.load 1 0
/--* t0 int +--* t1 int Generating: N003 ( 3, 3) [000002] J----+-N--- t2 = * GT int IN0004: i32.gt_s
/--* t2 int Generating: N004 ( 5, 5) [000003] -----+----- * JTRUE void $VN.Void
IN0005: br_if 0
...

Also addresses a few bits of @jakobbotsch's feedback on #121728. The SCC phase is moved later, some debug only stuff is now really debug only, etc.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[AndyAyersMS]

With the latest commit, we can alt-jit methods that just return. Lots of stuff still incomplete, but we have a lot we can fill in now.

[AndyAyersMS]

@SingleAccretion think I got most of your feedback, except leaving LABEL as is for now. Wasn't sure what you were commenting on for the prolog.

Please take another look.

[SingleAccretion]

Thank you for addressing the feedback, it looks much nicer now! I've left a few comments.

[AndyAyersMS]

@SingleAccretion thanks again, pushed another update

[SingleAccretion]

LGTM modulo the genFnProlog comment (#121973 (comment)) and one suggestion.

[AndyAyersMS]

@dotnet/jit-contrib ping

[AndyAyersMS]

@jakobbotsch now using a common genEmitEndBlock.
@adamperlin any other notes you want to add?

[jakobbotsch]

Looks great to me now.

[AndyAyersMS]

Not easy to get Roslyn to emit an actual switch, but here's an example of one making it to codegen (requires some fixes/workarounds not in this PR)

[adamperlin]

This looks good to me! I don't have any notes I wanted to add at the moment!

[AndyAyersMS]

Emit plausible Wasm control flow for blocks during genCodeForBBList.

Also add a bit of support for relop codegen, so blocks ending in branches have something to use.

Contributes to #121178.

[Copilot]

Pull request overview

This PR implements WebAssembly control flow code generation during the genCodeForBBList phase, enabling the JIT to emit structured control flow for Wasm blocks, loops, and branches. The implementation includes basic relational operator (relop) support for conditional branches.

Key changes include:

• Addition of Wasm control flow and relational operation instructions to the instruction table
• Movement of WasmInterval class from fgwasm.cpp to fgwasm.h for use during code generation
• Integration of the Wasm control flow transformation phases into the compilation pipeline (non-DEBUG builds)
• Implementation of control flow instruction emission in genCodeForBBlist, including block/loop/end nesting and branch depth calculation
• Basic GT_GT (greater than) relational operator codegen support

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
instrswasm.h	Adds Wasm control flow instructions (block, loop, if, else, end, br, br_if, br_table, return) and relational operators (eqz, eq, ne, lt, gt, le, ge for i32, i64, f32, f64 types)
fgwasm.h	Moves WasmInterval class definition from .cpp to header for codegen access
fgwasm.cpp	Moves WasmInterval to header, adds block reordering with branch condition reversal, adds debug dump functions, removes debug-only control flow simulation code
jitconfigvalues.h	Removes JitWasmControlFlow debug config option (now enabled for TARGET_WASM)
compiler.h	Adds WasmInterval forward declaration and fgWasmIntervals field to store control flow intervals for codegen
compiler.cpp	Moves Wasm SCC transformation and control flow phases from DEBUG-only to TARGET_WASM builds, repositions them in compilation pipeline
lowerwasm.cpp	Implements LowerJTrue to defer branch handling to codegen instead of using NYI
emitwasm.h	Adds code_t typedef for instruction opcodes
emitwasm.cpp	Implements insOpcode lookup, emitOutputInstr for IF_OPCODE/IF_ULEB128 formats, emitJumpKindToIns mapping, placeholder getInsExecutionCharacteristics
emitjmps.h	Defines Wasm jump kinds: br, br_if, br_table
codegenwasm.cpp	Implements genFnProlog, adds GT_GT to tree node codegen, implements inst_JMP/inst_LABEL for Wasm depth-based branching
codegen.h	Adds Wasm-specific inst_JMP and inst_LABEL declarations taking depth parameter
codegenlinear.cpp	Adds Wasm control flow stack management, emits block/loop/end instructions around blocks, generates Wasm branches (br, br_if, br_table) at block ends with depth calculation
CMakeLists.txt	Moves fgwasm.cpp from common JIT sources to TARGET_WASM-specific sources

[AndyAyersMS]

FYI @dotnet/jit-contrib @SingleAccretion

This won't get much testing in CI... locally it lets us get a simple method like

intFoo(inta,intb){if(a>b)returnb;returna;}

through more of codegen. Prolog gen stubbed out for now.

=============== Generating BB01 [0000] [000..004) -> BB02(0.5),BB03(0.5) (cond), preds={} succs={BB03,BB02} flags=0x00000000.00000011: i LIR
BB01 IN (2)={V00 V01}
OUT(2)={V00 V01}
Change life 0000000000000000 {} -> 0000000000000003 {V00 V01}
Debug: New V00 debug range: first
Debug: New V01 debug range: first
L_M10749_BB01:
Mapped BB01 to G_M10749_IG02
IN0001: block
Scope info: begin block BB01, IL range [000..004)
Added IP mapping: 0x0000 STACK_EMPTY (G_M10749_IG02,ins#1,ofs#1) label
Generating: [000008] ----------- IL_OFFSET void INLRT @ 0x000[E--]
Generating: N001 ( 1, 1) [000000] -----+----- t0 = LCL_VAR int V00 arg0 u:1 $80
IN0002: i32.load 1 4
Generating: N002 ( 1, 1) [000001] -----+----- t1 = LCL_VAR int V01 arg1 u:1 $81
IN0003: i32.load 1 0
/--* t0 int +--* t1 int Generating: N003 ( 3, 3) [000002] J----+-N--- t2 = * GT int IN0004: i32.gt_s
/--* t2 int Generating: N004 ( 5, 5) [000003] -----+----- * JTRUE void $VN.Void
IN0005: br_if 0
...

Also addresses a few bits of @jakobbotsch's feedback on #121728. The SCC phase is moved later, some debug only stuff is now really debug only, etc.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[AndyAyersMS]

With the latest commit, we can alt-jit methods that just return. Lots of stuff still incomplete, but we have a lot we can fill in now.

[AndyAyersMS]

@SingleAccretion think I got most of your feedback, except leaving LABEL as is for now. Wasn't sure what you were commenting on for the prolog.

Please take another look.

[SingleAccretion]

Thank you for addressing the feedback, it looks much nicer now! I've left a few comments.

[AndyAyersMS]

@SingleAccretion thanks again, pushed another update

[SingleAccretion]

LGTM modulo the genFnProlog comment (#121973 (comment)) and one suggestion.

[AndyAyersMS]

@dotnet/jit-contrib ping

[AndyAyersMS]

@jakobbotsch now using a common genEmitEndBlock.
@adamperlin any other notes you want to add?

[jakobbotsch]

Looks great to me now.

[AndyAyersMS]

Not easy to get Roslyn to emit an actual switch, but here's an example of one making it to codegen (requires some fixes/workarounds not in this PR)

[adamperlin]

This looks good to me! I don't have any notes I wanted to add at the moment!

[AndyAyersMS]

Emit plausible Wasm control flow for blocks during genCodeForBBList.

Also add a bit of support for relop codegen, so blocks ending in branches have something to use.

Contributes to #121178.

[Copilot]

Pull request overview

This PR implements WebAssembly control flow code generation during the genCodeForBBList phase, enabling the JIT to emit structured control flow for Wasm blocks, loops, and branches. The implementation includes basic relational operator (relop) support for conditional branches.

Key changes include:

• Addition of Wasm control flow and relational operation instructions to the instruction table
• Movement of WasmInterval class from fgwasm.cpp to fgwasm.h for use during code generation
• Integration of the Wasm control flow transformation phases into the compilation pipeline (non-DEBUG builds)
• Implementation of control flow instruction emission in genCodeForBBlist, including block/loop/end nesting and branch depth calculation
• Basic GT_GT (greater than) relational operator codegen support

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
instrswasm.h	Adds Wasm control flow instructions (block, loop, if, else, end, br, br_if, br_table, return) and relational operators (eqz, eq, ne, lt, gt, le, ge for i32, i64, f32, f64 types)
fgwasm.h	Moves WasmInterval class definition from .cpp to header for codegen access
fgwasm.cpp	Moves WasmInterval to header, adds block reordering with branch condition reversal, adds debug dump functions, removes debug-only control flow simulation code
jitconfigvalues.h	Removes JitWasmControlFlow debug config option (now enabled for TARGET_WASM)
compiler.h	Adds WasmInterval forward declaration and fgWasmIntervals field to store control flow intervals for codegen
compiler.cpp	Moves Wasm SCC transformation and control flow phases from DEBUG-only to TARGET_WASM builds, repositions them in compilation pipeline
lowerwasm.cpp	Implements LowerJTrue to defer branch handling to codegen instead of using NYI
emitwasm.h	Adds code_t typedef for instruction opcodes
emitwasm.cpp	Implements insOpcode lookup, emitOutputInstr for IF_OPCODE/IF_ULEB128 formats, emitJumpKindToIns mapping, placeholder getInsExecutionCharacteristics
emitjmps.h	Defines Wasm jump kinds: br, br_if, br_table
codegenwasm.cpp	Implements genFnProlog, adds GT_GT to tree node codegen, implements inst_JMP/inst_LABEL for Wasm depth-based branching
codegen.h	Adds Wasm-specific inst_JMP and inst_LABEL declarations taking depth parameter
codegenlinear.cpp	Adds Wasm control flow stack management, emits block/loop/end instructions around blocks, generates Wasm branches (br, br_if, br_table) at block ends with depth calculation
CMakeLists.txt	Moves fgwasm.cpp from common JIT sources to TARGET_WASM-specific sources

[AndyAyersMS]

FYI @dotnet/jit-contrib @SingleAccretion

This won't get much testing in CI... locally it lets us get a simple method like

intFoo(inta,intb){if(a>b)returnb;returna;}

through more of codegen. Prolog gen stubbed out for now.

=============== Generating BB01 [0000] [000..004) -> BB02(0.5),BB03(0.5) (cond), preds={} succs={BB03,BB02} flags=0x00000000.00000011: i LIR
BB01 IN (2)={V00 V01}
OUT(2)={V00 V01}
Change life 0000000000000000 {} -> 0000000000000003 {V00 V01}
Debug: New V00 debug range: first
Debug: New V01 debug range: first
L_M10749_BB01:
Mapped BB01 to G_M10749_IG02
IN0001: block
Scope info: begin block BB01, IL range [000..004)
Added IP mapping: 0x0000 STACK_EMPTY (G_M10749_IG02,ins#1,ofs#1) label
Generating: [000008] ----------- IL_OFFSET void INLRT @ 0x000[E--]
Generating: N001 ( 1, 1) [000000] -----+----- t0 = LCL_VAR int V00 arg0 u:1 $80
IN0002: i32.load 1 4
Generating: N002 ( 1, 1) [000001] -----+----- t1 = LCL_VAR int V01 arg1 u:1 $81
IN0003: i32.load 1 0
/--* t0 int +--* t1 int Generating: N003 ( 3, 3) [000002] J----+-N--- t2 = * GT int IN0004: i32.gt_s
/--* t2 int Generating: N004 ( 5, 5) [000003] -----+----- * JTRUE void $VN.Void
IN0005: br_if 0
...

Also addresses a few bits of @jakobbotsch's feedback on #121728. The SCC phase is moved later, some debug only stuff is now really debug only, etc.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[AndyAyersMS]

With the latest commit, we can alt-jit methods that just return. Lots of stuff still incomplete, but we have a lot we can fill in now.

[AndyAyersMS]

@SingleAccretion think I got most of your feedback, except leaving LABEL as is for now. Wasn't sure what you were commenting on for the prolog.

Please take another look.

[SingleAccretion]

Thank you for addressing the feedback, it looks much nicer now! I've left a few comments.

[AndyAyersMS]

@SingleAccretion thanks again, pushed another update

[SingleAccretion]

LGTM modulo the genFnProlog comment (#121973 (comment)) and one suggestion.

[AndyAyersMS]

@dotnet/jit-contrib ping

[AndyAyersMS]

@jakobbotsch now using a common genEmitEndBlock.
@adamperlin any other notes you want to add?

[jakobbotsch]

Looks great to me now.

[AndyAyersMS]

Not easy to get Roslyn to emit an actual switch, but here's an example of one making it to codegen (requires some fixes/workarounds not in this PR)

[adamperlin]

This looks good to me! I don't have any notes I wanted to add at the moment!

[AndyAyersMS]

Emit plausible Wasm control flow for blocks during genCodeForBBList.

Also add a bit of support for relop codegen, so blocks ending in branches have something to use.

Contributes to #121178.

[Copilot]

Pull request overview

This PR implements WebAssembly control flow code generation during the genCodeForBBList phase, enabling the JIT to emit structured control flow for Wasm blocks, loops, and branches. The implementation includes basic relational operator (relop) support for conditional branches.

Key changes include:

• Addition of Wasm control flow and relational operation instructions to the instruction table
• Movement of WasmInterval class from fgwasm.cpp to fgwasm.h for use during code generation
• Integration of the Wasm control flow transformation phases into the compilation pipeline (non-DEBUG builds)
• Implementation of control flow instruction emission in genCodeForBBlist, including block/loop/end nesting and branch depth calculation
• Basic GT_GT (greater than) relational operator codegen support

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 11 comments.

Show a summary per file

File	Description
instrswasm.h	Adds Wasm control flow instructions (block, loop, if, else, end, br, br_if, br_table, return) and relational operators (eqz, eq, ne, lt, gt, le, ge for i32, i64, f32, f64 types)
fgwasm.h	Moves WasmInterval class definition from .cpp to header for codegen access
fgwasm.cpp	Moves WasmInterval to header, adds block reordering with branch condition reversal, adds debug dump functions, removes debug-only control flow simulation code
jitconfigvalues.h	Removes JitWasmControlFlow debug config option (now enabled for TARGET_WASM)
compiler.h	Adds WasmInterval forward declaration and fgWasmIntervals field to store control flow intervals for codegen
compiler.cpp	Moves Wasm SCC transformation and control flow phases from DEBUG-only to TARGET_WASM builds, repositions them in compilation pipeline
lowerwasm.cpp	Implements LowerJTrue to defer branch handling to codegen instead of using NYI
emitwasm.h	Adds code_t typedef for instruction opcodes
emitwasm.cpp	Implements insOpcode lookup, emitOutputInstr for IF_OPCODE/IF_ULEB128 formats, emitJumpKindToIns mapping, placeholder getInsExecutionCharacteristics
emitjmps.h	Defines Wasm jump kinds: br, br_if, br_table
codegenwasm.cpp	Implements genFnProlog, adds GT_GT to tree node codegen, implements inst_JMP/inst_LABEL for Wasm depth-based branching
codegen.h	Adds Wasm-specific inst_JMP and inst_LABEL declarations taking depth parameter
codegenlinear.cpp	Adds Wasm control flow stack management, emits block/loop/end instructions around blocks, generates Wasm branches (br, br_if, br_table) at block ends with depth calculation
CMakeLists.txt	Moves fgwasm.cpp from common JIT sources to TARGET_WASM-specific sources

[AndyAyersMS]

FYI @dotnet/jit-contrib @SingleAccretion

This won't get much testing in CI... locally it lets us get a simple method like

intFoo(inta,intb){if(a>b)returnb;returna;}

through more of codegen. Prolog gen stubbed out for now.

=============== Generating BB01 [0000] [000..004) -> BB02(0.5),BB03(0.5) (cond), preds={} succs={BB03,BB02} flags=0x00000000.00000011: i LIR
BB01 IN (2)={V00 V01}
OUT(2)={V00 V01}
Change life 0000000000000000 {} -> 0000000000000003 {V00 V01}
Debug: New V00 debug range: first
Debug: New V01 debug range: first
L_M10749_BB01:
Mapped BB01 to G_M10749_IG02
IN0001: block
Scope info: begin block BB01, IL range [000..004)
Added IP mapping: 0x0000 STACK_EMPTY (G_M10749_IG02,ins#1,ofs#1) label
Generating: [000008] ----------- IL_OFFSET void INLRT @ 0x000[E--]
Generating: N001 ( 1, 1) [000000] -----+----- t0 = LCL_VAR int V00 arg0 u:1 $80
IN0002: i32.load 1 4
Generating: N002 ( 1, 1) [000001] -----+----- t1 = LCL_VAR int V01 arg1 u:1 $81
IN0003: i32.load 1 0
/--* t0 int +--* t1 int Generating: N003 ( 3, 3) [000002] J----+-N--- t2 = * GT int IN0004: i32.gt_s
/--* t2 int Generating: N004 ( 5, 5) [000003] -----+----- * JTRUE void $VN.Void
IN0005: br_if 0
...

Also addresses a few bits of @jakobbotsch's feedback on #121728. The SCC phase is moved later, some debug only stuff is now really debug only, etc.

[dotnet-policy-service]

Tagging subscribers to 'arch-wasm': @lewing, @pavelsavara
See info in area-owners.md if you want to be subscribed.

[AndyAyersMS]

With the latest commit, we can alt-jit methods that just return. Lots of stuff still incomplete, but we have a lot we can fill in now.

[AndyAyersMS]

@SingleAccretion think I got most of your feedback, except leaving LABEL as is for now. Wasn't sure what you were commenting on for the prolog.

Please take another look.

[SingleAccretion]

Thank you for addressing the feedback, it looks much nicer now! I've left a few comments.

[AndyAyersMS]

@SingleAccretion thanks again, pushed another update

[SingleAccretion]

LGTM modulo the genFnProlog comment (#121973 (comment)) and one suggestion.

[AndyAyersMS]

@dotnet/jit-contrib ping

[AndyAyersMS]

@jakobbotsch now using a common genEmitEndBlock.
@adamperlin any other notes you want to add?

[jakobbotsch]

Looks great to me now.

[AndyAyersMS]

Not easy to get Roslyn to emit an actual switch, but here's an example of one making it to codegen (requires some fixes/workarounds not in this PR)

[adamperlin]

This looks good to me! I don't have any notes I wanted to add at the moment!