Unverified Commit 9fe04e0c authored by Nathan Gauër's avatar Nathan Gauër Committed by GitHub
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[IR] Add require-logical-module module flag (#193502) 

This module flag is optional and can be set to require the use of
logical alloca/gep instructions.
This flag will have 2 usages:

- tell optimization which flavor of GEP/alloca to emit
- fail loudly if a GEP/alloca is emitted in a module targeting logical.
parent dc79e2a9

llvm/docs/LangRef.rst

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@@ -9253,6 +9253,16 @@ flags metadata, using the following key-value pairs: 
       * 2 --- CFG uses the "dispatch" mechanism. This calls a dispatcher

         function which both checks and then calls the target.













Other Module Flags













------------------

























``require-logical-pointer``













    This flag indicates this module must only use logical pointer intrinsics













    such as :ref:`@llvm.structured.gep <i_structured_gep>` or













    :ref:`@llvm.structured.alloca <i_structured_alloca>`.













    Using a normal :ref:`getelementptr <i_getelementptr>` or













    :ref:`alloca <i_alloca>` is illegal.



























Embedded Objects Names Metadata















===============================







































llvm/lib/IR/Verifier.cpp



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@@ -4488,6 +4488,11 @@ void Verifier::visitShuffleVectorInst(ShuffleVectorInst &SV) {













}































void Verifier::visitGetElementPtrInst(GetElementPtrInst &GEP) {













  if (auto *MD = mdconst::extract_or_null<ConstantInt>(













          GEP.getModule()->getModuleFlag("require-logical-pointer")))













    Check(!MD->getZExtValue(),













          "Non-logical getelementptr disallowed for this module.");





























  Type *TargetTy = GEP.getPointerOperandType()->getScalarType();































  Check(isa<PointerType>(TargetTy),










@@ -4749,6 +4754,11 @@ void Verifier::verifySwiftErrorValue(const Value *SwiftErrorVal) {













}































void Verifier::visitAllocaInst(AllocaInst &AI) {













  if (auto *MD = mdconst::extract_or_null<ConstantInt>(













          AI.getModule()->getModuleFlag("require-logical-pointer")))













    Check(!MD->getZExtValue(),













          "Non-logical alloca disallowed for this module.");





























  Type *Ty = AI.getAllocatedType();















  SmallPtrSet<Type*, 4> Visited;















  Check(Ty->isSized(&Visited), "Cannot allocate unsized type", &AI);

































llvm/test/Verifier/logical-pointer-notrequired.ll
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; RUN: llvm-as -disable-output %s



























%S = type { i32, i32 }



























define void @normal_gep(ptr %src, i32 %index) {













entry:













  %ptr = getelementptr i8, ptr %src, i32 0













  ret void













}



























define void @structured_gep(ptr %src, i32 %index) {













entry:













  %ptr = call ptr (ptr, ...) @llvm.structured.gep.p0(ptr elementtype([0 x %S]) %src, i32 %index, i32 1)













  ret void













}



























define void @normal_alloca() {













entry:













  %tmp = alloca i32













  ret void













}



























define void @structured_alloca(ptr %src, i32 %index) {













entry:













  %tmp = call elementtype(i32) ptr @llvm.structured.alloca()













  ret void













}



























!llvm.module.flags = !{!0}













!0 = !{i32 1, !"require-logical-pointer", i32 0}
























llvm/test/Verifier/logical-pointer-required-failure.ll
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; RUN: not llvm-as -disable-output %s 2>&1 | FileCheck %s



























define void @gep_with_logical_required(ptr %src, i32 %index) {













entry:













; CHECK: Non-logical getelementptr disallowed for this module.













  %ptr = getelementptr i8, ptr %src, i32 0













  ret void













}



























define void @alloca_with_logical_required() {













entry:













; CHECK: Non-logical alloca disallowed for this module.













  %tmp = alloca i32













  ret void













}



























!llvm.module.flags = !{!0}













!0 = !{i32 1, !"require-logical-pointer", i32 1}
























llvm/test/Verifier/logical-pointer-required.ll
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; RUN: llvm-as -disable-output %s



























%S = type { i32, i32 }



























define void @structured_gep_allowed(ptr %src, i32 %index) {













entry:













  %ptr = call ptr (ptr, ...) @llvm.structured.gep.p0(ptr elementtype([0 x %S]) %src, i32 %index, i32 1)













  ret void













}



























define void @structured_alloca_allowed(ptr %src, i32 %index) {













entry:













  %tmp = call elementtype(i32) ptr @llvm.structured.alloca()













  ret void













}



























!llvm.module.flags = !{!0}













!0 = !{i32 1, !"require-logical-pointer", i32 1}