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[GlobalISel][IRTranslator] Add special case support for ~memory inline asm clobber. 

This is a one off special case, since actually implementing full inline asm
support will be much more involved. This lets us compile a lot more code as a
common simple case.

Differential Revision: https://reviews.llvm.org/D74201
This commit is contained in:
Amara Emerson 2020-02-07 01:07:57 -08:00
parent 1ff411295f
commit 28d22c2c9c
2 changed files with 33 additions and 5 deletions
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24
llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
View File

@ -1559,8 +1559,16 @@ bool IRTranslator::translateKnownIntrinsic(const CallInst &CI, Intrinsic::ID ID,
bool IRTranslator::translateInlineAsm(const CallInst &CI,
MachineIRBuilder &MIRBuilder) {
const InlineAsm &IA = cast<InlineAsm>(*CI.getCalledValue());
if (!IA.getConstraintString().empty())
return false;
StringRef ConstraintStr = IA.getConstraintString();
bool HasOnlyMemoryClobber = false;
if (!ConstraintStr.empty()) {
// Until we have full inline assembly support, we just try to handle the
// very simple case of just "~{memory}" to avoid falling back so often.
if (ConstraintStr != "~{memory}")
return false;
HasOnlyMemoryClobber = true;
}
unsigned ExtraInfo = 0;
if (IA.hasSideEffects())
@ -1568,9 +1576,15 @@ bool IRTranslator::translateInlineAsm(const CallInst &CI,
if (IA.getDialect() == InlineAsm::AD_Intel)
ExtraInfo |= InlineAsm::Extra_AsmDialect;
MIRBuilder.buildInstr(TargetOpcode::INLINEASM)
.addExternalSymbol(IA.getAsmString().c_str())
.addImm(ExtraInfo);
// HACK: special casing for ~memory.
if (HasOnlyMemoryClobber)
ExtraInfo |= (InlineAsm::Extra_MayLoad | InlineAsm::Extra_MayStore);
auto Inst = MIRBuilder.buildInstr(TargetOpcode::INLINEASM)
.addExternalSymbol(IA.getAsmString().c_str())
.addImm(ExtraInfo);
if (const MDNode *SrcLoc = CI.getMetadata("srcloc"))
Inst.addMetadata(SrcLoc);
return true;
}

14
llvm/test/CodeGen/AArch64/GlobalISel/translate-inline-asm.ll Normal file
View File

@ -0,0 +1,14 @@
; RUN: llc -mtriple=aarch64-darwin-ios13 -O0 -global-isel -stop-after=irtranslator -o - %s | FileCheck %s
; The update_mir_test_checks script doesn't seem to handle INLINE_ASM well. Write this manually.
define void @asm_simple_memory_clobber() {
; CHECK-LABEL: name: asm_simple_memory_clobber
; CHECK: INLINEASM &"", 25
; CHECK: INLINEASM &"", 1
call void asm sideeffect "", "~{memory}"(), !srcloc !0
call void asm sideeffect "", ""(), !srcloc !0
ret void
}
!0 = !{i32 70}