inline: re-introduce some callee body checks

Author: davidtwco

compiler/rustc_mir_transform/src/inline.rs

@@ -195,10 +195,37 @@ impl<'tcx> Inliner<'tcx> for ForceInliner<'tcx> {
 &self,
  _:&CallSite<'tcx>,
 callee_body:&Body<'tcx>,
-_:&CodegenFnAttrs,
+callee_attrs:&CodegenFnAttrs,
  _:bool,
 ) -> Result<(),&'staticstr>{
-ifletSome(_) = callee_body.tainted_by_errors{Err("body has errors")}else{Ok(())}
+if callee_body.tainted_by_errors.is_some(){
+returnErr("body has errors");
+}
+
+let caller_attrs = self.tcx().codegen_fn_attrs(self.caller_def_id());
+if callee_attrs.instruction_set != caller_attrs.instruction_set
+ && callee_body
+.basic_blocks
+.iter()
+.any(|bb| matches!(bb.terminator().kind,TerminatorKind::InlineAsm{ .. }))
+{
+// During the attribute checking stage we allow a callee with no
+// instruction_set assigned to count as compatible with a function that does
+// assign one. However, during this stage we require an exact match when any
+// inline-asm is detected. LLVM will still possibly do an inline later on
+// if the no-attribute function ends up with the same instruction set anyway.
+Err("cannot move inline-asm across instruction sets")
+}elseif callee_body
+.basic_blocks
+.iter()
+.any(|bb| matches!(bb.terminator().kind,TerminatorKind::TailCall{ .. }))
+{
+// FIXME(explicit_tail_calls): figure out how exactly functions containing tail
+// calls can be inlined (and if they even should)
+Err("can't inline functions with tail calls")
+}else{
+Ok(())
+}
 }
 
 fninline_limit_for_block(&self) -> Option<usize>{

tests/ui/force-inlining/asm.rs

@@ -0,0 +1,68 @@
+//@ build-fail
+//@ compile-flags: --crate-type=lib --target thumbv4t-none-eabi
+//@ needs-llvm-components: arm
+
+// Checks that forced inlining won't mix asm with incompatible instruction sets.
+
+#![crate_type = "lib"]
+#![feature(rustc_attrs)]
+#![feature(no_core, lang_items)]
+#![no_core]
+
+#[lang = "sized"]
+pubtraitSized{}
+#[lang = "copy"]
+pubtraitCopy{}
+#[lang = "freeze"]
+pubunsafetraitFreeze{}
+
+#[lang = "start"]
+fnstart<T>(_main:fn() -> T,_argc:isize,_argv:*const*constu8,_sigpipe:u8) -> isize{
+0
+}
+
+#[rustc_builtin_macro]
+#[macro_export]
+macro_rules! asm {
+("assembly template",
+ $(operands,)*
+ $(options($(option),*))?
+) => {
+/* compiler built-in */
+};
+}
+
+#[instruction_set(arm::a32)]
+#[rustc_force_inline]
+fninstruction_set_a32(){}
+
+#[instruction_set(arm::t32)]
+#[rustc_force_inline]
+fninstruction_set_t32(){}
+
+#[rustc_force_inline]
+fninstruction_set_default(){}
+
+#[rustc_force_inline]
+fninline_always_and_using_inline_asm(){
+unsafe{asm!("/* do nothing */")};
+}
+
+#[instruction_set(arm::t32)]
+pubfnt32(){
+instruction_set_a32();
+//~^ ERROR `instruction_set_a32` could not be inlined into `t32` but is required to be inlined
+instruction_set_t32();
+instruction_set_default();
+inline_always_and_using_inline_asm();
+//~^ ERROR `inline_always_and_using_inline_asm` could not be inlined into `t32` but is required to be inlined
+}
+
+pubfndefault(){
+instruction_set_a32();
+//~^ ERROR `instruction_set_a32` could not be inlined into `default` but is required to be inlined
+instruction_set_t32();
+//~^ ERROR `instruction_set_t32` could not be inlined into `default` but is required to be inlined
+instruction_set_default();
+inline_always_and_using_inline_asm();
+}

tests/ui/force-inlining/asm.stderr

@@ -0,0 +1,34 @@
+error: `instruction_set_a32` could not be inlined into `t32` but is required to be inlined
+ --> $DIR/asm.rs:53:5
+ |
+LL | instruction_set_a32();
+ | ^^^^^^^^^^^^^^^^^^^^^ ...`instruction_set_a32` called here
+ |
+ = note: could not be inlined due to: incompatible instruction set
+
+error: `inline_always_and_using_inline_asm` could not be inlined into `t32` but is required to be inlined
+ --> $DIR/asm.rs:57:5
+ |
+LL | inline_always_and_using_inline_asm();
+ | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...`inline_always_and_using_inline_asm` called here
+ |
+ = note: could not be inlined due to: cannot move inline-asm across instruction sets
+
+error: `instruction_set_a32` could not be inlined into `default` but is required to be inlined
+ --> $DIR/asm.rs:62:5
+ |
+LL | instruction_set_a32();
+ | ^^^^^^^^^^^^^^^^^^^^^ ...`instruction_set_a32` called here
+ |
+ = note: could not be inlined due to: incompatible instruction set
+
+error: `instruction_set_t32` could not be inlined into `default` but is required to be inlined
+ --> $DIR/asm.rs:64:5
+ |
+LL | instruction_set_t32();
+ | ^^^^^^^^^^^^^^^^^^^^^ ...`instruction_set_t32` called here
+ |
+ = note: could not be inlined due to: incompatible instruction set
+
+error: aborting due to 4 previous errors
+