llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Stephen Tozer (SLTozer) <details> <summary>Changes</summary> Following the [previous patch](https://github.com/llvm/llvm-project/pull/110000) which adds the "extend lifetimes" flag without (almost) any functionality, this patch adds the real feature by allowing Clang to emit fake uses. These are emitted as a new form of cleanup, set for variable addresses, which just emits a fake use intrinsic when the variable falls out of scope. The code for achieving this is simple, with most of the logic centered on determining whether to emit a fake use for a given address, and on ensuring that fake uses are ignored in a few cases. All code originally written by @<!-- -->wolfy1961, while I'll be handling the review. --- Patch is 26.63 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/110102.diff 21 Files Affected: - (modified) clang/lib/CodeGen/CGCall.cpp (+20-10) - (modified) clang/lib/CodeGen/CGCleanup.cpp (+5-2) - (modified) clang/lib/CodeGen/CGCleanup.h (+8) - (modified) clang/lib/CodeGen/CGDecl.cpp (+69) - (modified) clang/lib/CodeGen/CodeGenFunction.cpp (+3-3) - (modified) clang/lib/CodeGen/CodeGenFunction.h (+16) - (modified) clang/lib/CodeGen/CodeGenModule.h (+4) - (modified) clang/lib/CodeGen/EHScopeStack.h (+7-2) - (added) clang/test/CodeGen/extend-liveness1.c (+29) - (added) clang/test/CodeGen/extend-liveness2.cpp (+34) - (added) clang/test/CodeGen/fake-use-determinism.c (+18) - (added) clang/test/CodeGen/fake-use-lambda.cpp (+43) - (added) clang/test/CodeGen/fake-use-landingpad.c (+16) - (added) clang/test/CodeGen/fake-use-noreturn.cpp (+27) - (added) clang/test/CodeGen/fake-use-return-line.c (+15) - (added) clang/test/CodeGen/fake-use-sanitizer.cpp (+37) - (added) clang/test/CodeGen/fake-use-scalar.c (+22) - (added) clang/test/CodeGen/fake-use-small-aggs.c (+24) - (added) clang/test/CodeGen/fake-use-while.c (+18) - (added) clang/test/CodeGen/fake-use.cpp (+44) - (added) clang/test/CodeGen/no-fake-use-O0.cpp (+50) ``````````diff diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp index 4ae981e4013e9c..13c556a4e20a13 100644 --- a/clang/lib/CodeGen/CGCall.cpp +++ b/clang/lib/CodeGen/CGCall.cpp @@ -3566,16 +3566,26 @@ static llvm::StoreInst *findDominatingStoreToReturnValue(CodeGenFunction &CGF) { llvm::BasicBlock *IP = CGF.Builder.GetInsertBlock(); if (IP->empty()) return nullptr; - // Look at directly preceding instruction, skipping bitcasts and lifetime - // markers. - for (llvm::Instruction &I : make_range(IP->rbegin(), IP->rend())) { - if (isa<llvm::BitCastInst>(&I)) - continue; - if (auto *II = dyn_cast<llvm::IntrinsicInst>(&I)) - if (II->getIntrinsicID() == llvm::Intrinsic::lifetime_end) - continue; - - return GetStoreIfValid(&I); + // Look at directly preceding instruction, skipping bitcasts, lifetime + // markers, and fake uses and their operands. + const llvm::Instruction *LoadIntoFakeUse = nullptr; + for (llvm::Instruction &I : make_range(IP->rbegin(), IP->rend())) { + // Ignore instructions that are just loads for fake uses; the load should + // immediately precede the fake use, so we only need to remember the + // operand for the last fake use seen. + if (LoadIntoFakeUse == &I) + continue; + if (isa<llvm::BitCastInst>(&I)) + continue; + if (auto *II = dyn_cast<llvm::IntrinsicInst>(&I)) { + if (II->getIntrinsicID() == llvm::Intrinsic::lifetime_end) + continue; + + if (II->getIntrinsicID() == llvm::Intrinsic::fake_use) { + LoadIntoFakeUse = dyn_cast<llvm::Instruction>(II->getArgOperand(0)); + continue; + } + } return GetStoreIfValid(&I); } return nullptr; } diff --git a/clang/lib/CodeGen/CGCleanup.cpp b/clang/lib/CodeGen/CGCleanup.cpp index 5d253c92a38a81..82532e182bebbd 100644 --- a/clang/lib/CodeGen/CGCleanup.cpp +++ b/clang/lib/CodeGen/CGCleanup.cpp @@ -112,11 +112,11 @@ void EHScopeStack::deallocate(size_t Size) { StartOfData += llvm::alignTo(Size, ScopeStackAlignment); } -bool EHScopeStack::containsOnlyLifetimeMarkers( +bool EHScopeStack::containsOnlyNoopCleanups( EHScopeStack::stable_iterator Old) const { for (EHScopeStack::iterator it = begin(); stabilize(it) != Old; it++) { EHCleanupScope *cleanup = dyn_cast<EHCleanupScope>(&*it); - if (!cleanup || !cleanup->isLifetimeMarker()) + if (!cleanup || !(cleanup->isLifetimeMarker() || cleanup->isFakeUse())) return false; } @@ -154,6 +154,7 @@ void *EHScopeStack::pushCleanup(CleanupKind Kind, size_t Size) { bool IsNormalCleanup = Kind & NormalCleanup; bool IsEHCleanup = Kind & EHCleanup; bool IsLifetimeMarker = Kind & LifetimeMarker; + bool IsFakeUse = Kind & FakeUse; // Per C++ [except.terminate], it is implementation-defined whether none, // some, or all cleanups are called before std::terminate. Thus, when @@ -176,6 +177,8 @@ void *EHScopeStack::pushCleanup(CleanupKind Kind, size_t Size) { InnermostEHScope = stable_begin(); if (IsLifetimeMarker) Scope->setLifetimeMarker(); + if (IsFakeUse) + Scope->setFakeUse(); // With Windows -EHa, Invoke llvm.seh.scope.begin() for EHCleanup // If exceptions are disabled/ignored and SEH is not in use, then there is no diff --git a/clang/lib/CodeGen/CGCleanup.h b/clang/lib/CodeGen/CGCleanup.h index c73c97146abc4d..ba78e5478ac373 100644 --- a/clang/lib/CodeGen/CGCleanup.h +++ b/clang/lib/CodeGen/CGCleanup.h @@ -87,6 +87,10 @@ class EHScope { LLVM_PREFERRED_TYPE(bool) unsigned IsLifetimeMarker : 1; + /// Whether this cleanup is a fake use + LLVM_PREFERRED_TYPE(bool) + unsigned IsFakeUse : 1; + /// Whether the normal cleanup should test the activation flag. LLVM_PREFERRED_TYPE(bool) unsigned TestFlagInNormalCleanup : 1; @@ -352,6 +356,7 @@ class alignas(8) EHCleanupScope : public EHScope { CleanupBits.IsEHCleanup = isEH; CleanupBits.IsActive = true; CleanupBits.IsLifetimeMarker = false; + CleanupBits.IsFakeUse = false; CleanupBits.TestFlagInNormalCleanup = false; CleanupBits.TestFlagInEHCleanup = false; CleanupBits.CleanupSize = cleanupSize; @@ -384,6 +389,9 @@ class alignas(8) EHCleanupScope : public EHScope { bool isLifetimeMarker() const { return CleanupBits.IsLifetimeMarker; } void setLifetimeMarker() { CleanupBits.IsLifetimeMarker = true; } + bool isFakeUse() const { return CleanupBits.IsFakeUse; } + void setFakeUse() { CleanupBits.IsFakeUse = true; } + bool hasActiveFlag() const { return ActiveFlag.isValid(); } Address getActiveFlag() const { return ActiveFlag; diff --git a/clang/lib/CodeGen/CGDecl.cpp b/clang/lib/CodeGen/CGDecl.cpp index 563f728e29d781..7fdf18f3ca2e7b 100644 --- a/clang/lib/CodeGen/CGDecl.cpp +++ b/clang/lib/CodeGen/CGDecl.cpp @@ -1353,6 +1353,14 @@ void CodeGenFunction::EmitLifetimeEnd(llvm::Value *Size, llvm::Value *Addr) { C->setDoesNotThrow(); } +void CodeGenFunction::EmitFakeUse(Address Addr) { + auto NL = ApplyDebugLocation::CreateEmpty(*this); + llvm::Value *V = Builder.CreateLoad(Addr, "fake.use"); + llvm::CallInst *C = Builder.CreateCall(CGM.getLLVMFakeUseFn(), {V}); + C->setDoesNotThrow(); + C->setTailCallKind(llvm::CallInst::TCK_NoTail); +} + void CodeGenFunction::EmitAndRegisterVariableArrayDimensions( CGDebugInfo *DI, const VarDecl &D, bool EmitDebugInfo) { // For each dimension stores its QualType and corresponding @@ -1412,6 +1420,39 @@ void CodeGenFunction::EmitAndRegisterVariableArrayDimensions( } } +/// Return the maximum size of an aggregate for which we generate a fake use +/// intrinsic when -fextend-lifetimes is in effect. +static uint64_t maxFakeUseAggregateSize(const ASTContext &C) { + return 4 * C.getTypeSize(C.UnsignedIntTy); +} + +// Helper function to determine whether a variable's or parameter's lifetime +// should be extended. +static bool extendLifetime(const ASTContext &Context, const Decl *FuncDecl, + const VarDecl &D, + ImplicitParamDecl *CXXABIThisDecl) { + // When we're not inside a valid function it is unlikely that any + // lifetime extension is useful. + if (!FuncDecl) + return false; + if (FuncDecl->isImplicit()) + return false; + // Do not extend compiler-created variables except for the this pointer. + if (D.isImplicit() && &D != CXXABIThisDecl) + return false; + QualType Ty = D.getType(); + // No need to extend volatiles, they have a memory location. + if (Ty.isVolatileQualified()) + return false; + // Don't extend variables that exceed a certain size. + if (Context.getTypeSize(Ty) > maxFakeUseAggregateSize(Context)) + return false; + // Do not extend variables in nodebug functions. + if (FuncDecl->hasAttr<NoDebugAttr>()) + return false; + return true; +} + /// EmitAutoVarAlloca - Emit the alloca and debug information for a /// local variable. Does not emit initialization or destruction. CodeGenFunction::AutoVarEmission @@ -1664,6 +1705,17 @@ CodeGenFunction::EmitAutoVarAlloca(const VarDecl &D) { emission.getOriginalAllocatedAddress(), emission.getSizeForLifetimeMarkers()); + // Analogous to lifetime markers, we use a 'cleanup' to emit fake.use + // calls for local variables. We are exempting volatile variables and + // non-scalars larger than 4 times the size of an unsigned int (32 bytes). + // Larger non-scalars are often allocated in memory and may create unnecessary + // overhead. + if (CGM.getCodeGenOpts().ExtendLifetimes) { + if (extendLifetime(getContext(), CurCodeDecl, D, CXXABIThisDecl)) + EHStack.pushCleanup<FakeUse>(NormalFakeUse, + emission.getAllocatedAddress()); + } + return emission; } @@ -2523,6 +2575,14 @@ llvm::Function *CodeGenModule::getLLVMLifetimeEndFn() { return LifetimeEndFn; } +/// Lazily declare the @llvm.fake.use intrinsic. +llvm::Function *CodeGenModule::getLLVMFakeUseFn() { + if (!FakeUseFn) + FakeUseFn = llvm::Intrinsic::getDeclaration(&getModule(), + llvm::Intrinsic::fake_use); + return FakeUseFn; +} + namespace { /// A cleanup to perform a release of an object at the end of a /// function. This is used to balance out the incoming +1 of a @@ -2716,6 +2776,15 @@ void CodeGenFunction::EmitParmDecl(const VarDecl &D, ParamValue Arg, setAddrOfLocalVar(&D, DeclPtr); + // Push a FakeUse 'cleanup' object onto the EHStack for the parameter, + // which may be the 'this' pointer. This causes the emission of a fake.use + // call with the parameter as argument at the end of the function. + if (CGM.getCodeGenOpts().ExtendLifetimes || + (CGM.getCodeGenOpts().ExtendThisPtr && &D == CXXABIThisDecl)) { + if (extendLifetime(getContext(), CurCodeDecl, D, CXXABIThisDecl)) + EHStack.pushCleanup<FakeUse>(NormalFakeUse, DeclPtr); + } + // Emit debug info for param declarations in non-thunk functions. if (CGDebugInfo *DI = getDebugInfo()) { if (CGM.getCodeGenOpts().hasReducedDebugInfo() && !CurFuncIsThunk && diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp index eda96f3e352ce3..630a9c8db95fe5 100644 --- a/clang/lib/CodeGen/CodeGenFunction.cpp +++ b/clang/lib/CodeGen/CodeGenFunction.cpp @@ -403,9 +403,9 @@ void CodeGenFunction::FinishFunction(SourceLocation EndLoc) { // important to do this before we enter the return block or return // edges will be *really* confused. bool HasCleanups = EHStack.stable_begin() != PrologueCleanupDepth; - bool HasOnlyLifetimeMarkers = - HasCleanups && EHStack.containsOnlyLifetimeMarkers(PrologueCleanupDepth); - bool EmitRetDbgLoc = !HasCleanups || HasOnlyLifetimeMarkers; + bool HasOnlyNoopCleanups = + HasCleanups && EHStack.containsOnlyNoopCleanups(PrologueCleanupDepth); + bool EmitRetDbgLoc = !HasCleanups || HasOnlyNoopCleanups; std::optional<ApplyDebugLocation> OAL; if (HasCleanups) { diff --git a/clang/lib/CodeGen/CodeGenFunction.h b/clang/lib/CodeGen/CodeGenFunction.h index 3e2abbd9bc1094..1525eb0f09b6e5 100644 --- a/clang/lib/CodeGen/CodeGenFunction.h +++ b/clang/lib/CodeGen/CodeGenFunction.h @@ -718,6 +718,20 @@ class CodeGenFunction : public CodeGenTypeCache { } }; + // We are using objects of this 'cleanup' class to emit fake.use calls + // for -fextend-lifetimes and -fextend-this-ptr. They are placed at the end of + // a variable's scope analogous to lifetime markers. + class FakeUse final : public EHScopeStack::Cleanup { + Address Addr; + + public: + FakeUse(Address addr) : Addr(addr) {} + + void Emit(CodeGenFunction &CGF, Flags flags) override { + CGF.EmitFakeUse(Addr); + } + }; + /// Header for data within LifetimeExtendedCleanupStack. struct LifetimeExtendedCleanupHeader { /// The size of the following cleanup object. @@ -4975,6 +4989,8 @@ class CodeGenFunction : public CodeGenTypeCache { RValue EmitAtomicExpr(AtomicExpr *E); + void EmitFakeUse(Address Addr); + //===--------------------------------------------------------------------===// // Annotations Emission //===--------------------------------------------------------------------===// diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h index c58bb88035ca8a..71198134f17413 100644 --- a/clang/lib/CodeGen/CodeGenModule.h +++ b/clang/lib/CodeGen/CodeGenModule.h @@ -601,6 +601,9 @@ class CodeGenModule : public CodeGenTypeCache { /// void @llvm.lifetime.end(i64 %size, i8* nocapture <ptr>) llvm::Function *LifetimeEndFn = nullptr; + /// void @llvm.fake.use(...) + llvm::Function *FakeUseFn = nullptr; + std::unique_ptr<SanitizerMetadata> SanitizerMD; llvm::MapVector<const Decl *, bool> DeferredEmptyCoverageMappingDecls; @@ -1268,6 +1271,7 @@ class CodeGenModule : public CodeGenTypeCache { llvm::Function *getLLVMLifetimeStartFn(); llvm::Function *getLLVMLifetimeEndFn(); + llvm::Function *getLLVMFakeUseFn(); // Make sure that this type is translated. void UpdateCompletedType(const TagDecl *TD); diff --git a/clang/lib/CodeGen/EHScopeStack.h b/clang/lib/CodeGen/EHScopeStack.h index 0c667e80bb6d8c..ed11dc2bb05d73 100644 --- a/clang/lib/CodeGen/EHScopeStack.h +++ b/clang/lib/CodeGen/EHScopeStack.h @@ -87,6 +87,11 @@ enum CleanupKind : unsigned { LifetimeMarker = 0x8, NormalEHLifetimeMarker = LifetimeMarker | NormalAndEHCleanup, + + // FakeUse needs to be recognized as a special cleanup similar to lifetime + // markers chiefly to be ignored in most contexts. + FakeUse = 0x10, + NormalFakeUse = FakeUse | NormalCleanup, }; /// A stack of scopes which respond to exceptions, including cleanups @@ -352,8 +357,8 @@ class EHScopeStack { void popTerminate(); // Returns true iff the current scope is either empty or contains only - // lifetime markers, i.e. no real cleanup code - bool containsOnlyLifetimeMarkers(stable_iterator Old) const; + // noop cleanups, i.e. lifetime markers and fake uses. + bool containsOnlyNoopCleanups(stable_iterator Old) const; /// Determines whether the exception-scopes stack is empty. bool empty() const { return StartOfData == EndOfBuffer; } diff --git a/clang/test/CodeGen/extend-liveness1.c b/clang/test/CodeGen/extend-liveness1.c new file mode 100644 index 00000000000000..ef2d00eb6be312 --- /dev/null +++ b/clang/test/CodeGen/extend-liveness1.c @@ -0,0 +1,29 @@ +// RUN: %clang_cc1 %s -O2 -emit-llvm -fextend-lifetimes -o - | FileCheck %s +// Check that fake use calls are emitted at the correct locations, i.e. +// at the end of lexical blocks and at the end of the function. + +extern int use(int); +int glob1; +int glob2; +float globf; + +int foo(int i) { + // CHECK: define{{.*}}foo + if (i < 4) { + int j = i * 3; + if (glob1 > 3) { + float f = globf; + // CHECK: [[SSAVAL:%[a-z0-9]*]] = load float{{.*}}globf + j = f; + glob2 = j; + // CHECK: store{{.*}}glob2 + // CHECK-NEXT: call void (...) @llvm.fake.use(float [[SSAVAL]]) + } + glob1 = j; + // CHECK: store{{.*}}glob1 + // CHECK-NEXT: call void (...) @llvm.fake.use(i32 %j. + } + // CHECK: call void (...) @llvm.fake.use(i32 %i) + // CHECK-NEXT: ret + return 4; +} diff --git a/clang/test/CodeGen/extend-liveness2.cpp b/clang/test/CodeGen/extend-liveness2.cpp new file mode 100644 index 00000000000000..119c783c634806 --- /dev/null +++ b/clang/test/CodeGen/extend-liveness2.cpp @@ -0,0 +1,34 @@ +// RUN: %clang_cc1 %s -O2 -emit-llvm -fextend-lifetimes -fcxx-exceptions -fexceptions -o - | FileCheck %s +// REQUIRES: x86-registered-target +// This test checks that the fake_use concept works with exception handling and that we +// can handle the __int128 data type. + +class A { +public: + A(int i) : m_i(i) {} + void func(__int128 i128); + + int m_i; +}; + +extern int bar(); +extern void foo(); +int glob; + +void A::func(__int128 i128) { + int j = 4; + try { + int k = bar(); + foo(); + // CHECK: [[SSAVAL:%[a-z0-9]*]] = invoke{{.*}}bar + glob = 0; + // CHECK: store{{.*}}glob + // CHECK-NEXT: call void (...) @llvm.fake.use(i32 [[SSAVAL]]) + } catch (...) { + foo(); + } + // CHECK-LABEL: try.cont: + // CHECK-DAG: call void (...) @llvm.fake.use({{.*%this}}) + // CHECK-DAG: call void (...) @llvm.fake.use(i128 %i128.sroa.0.0.insert.insert) + // CHECK: ret void +} diff --git a/clang/test/CodeGen/fake-use-determinism.c b/clang/test/CodeGen/fake-use-determinism.c new file mode 100644 index 00000000000000..d62efbb4efe7ee --- /dev/null +++ b/clang/test/CodeGen/fake-use-determinism.c @@ -0,0 +1,18 @@ +// RUN: %clang -S -O2 -emit-llvm -fextend-lifetimes %s -o - | FileCheck %s +// REQUIRES: asserts +// +// We are checking that the fake.use calls for i, j and k appear +// in a particular order. It is not the order itself that is important +// but that it remains the same between different test runs. + +// CHECK: call {{.*}}void (...) @llvm.fake.use(i32 %k) +// CHECK-NEXT: call {{.*}}void (...) @llvm.fake.use(i32 %j) +// CHECK-NEXT: call {{.*}}void (...) @llvm.fake.use(i32 %i) + +extern void bar(); +void foo(int i, int j, int k) +{ + for (int l = 0; l < i; l++) { + bar(); + } +} diff --git a/clang/test/CodeGen/fake-use-lambda.cpp b/clang/test/CodeGen/fake-use-lambda.cpp new file mode 100644 index 00000000000000..fd4881b9bcd531 --- /dev/null +++ b/clang/test/CodeGen/fake-use-lambda.cpp @@ -0,0 +1,43 @@ +// RUN: %clang_cc1 %s -triple=%itanium_abi_triple -O1 -emit-llvm -fextend-lifetimes -o - | FileCheck %s +// Make sure we don't crash compiling a lambda that is not nested in a function. +// We also check that fake uses are properly issued in lambdas. + +int glob; + +extern int foo(); + +struct S { + static const int a; +}; + +const int S::a = [](int b) __attribute__((noinline)) { + return b * foo(); +} +(glob); + +int func(int param) { + return ([=](int lambdaparm) __attribute__((noinline))->int { + int lambdalocal = lambdaparm * 2; + return lambdalocal; + }(glob)); +} + +// We are looking for the first lambda's call operator, which should contain +// 2 fake uses, one for 'b' and one for its 'this' pointer (in that order). +// The mangled function name contains a $_0, followed by 'cl'. +// This lambda is an orphaned lambda, i.e. one without lexical parent. +// +// CHECK: define internal {{.+\"_Z.+\$_0.*cl.*\"}} +// CHECK-NOT: ret +// CHECK: fake.use(i32 +// CHECK-NOT: ret +// CHECK: fake.use(ptr + +// The second lambda. We are looking for 3 fake uses. +// CHECK: define internal {{.+\"_Z.+\$_0.*cl.*\"}} +// CHECK-NOT: ret +// CHECK: fake.use(i32 +// CHECK-NOT: ret +// CHECK: fake.use(i32 +// CHECK-NOT: ret +// CHECK: fake.use(ptr diff --git a/clang/test/CodeGen/fake-use-landingpad.c b/clang/test/CodeGen/fake-use-landingpad.c new file mode 100644 index 00000000000000..91526f29936146 --- /dev/null +++ b/clang/test/CodeGen/fake-use-landingpad.c @@ -0,0 +1,16 @@ +// RUN: %clang_cc1 %s -O3 -emit-llvm -fextend-lifetimes -fexceptions -o - | FileCheck %s + +// Check that fake uses do not mistakenly cause a landing pad to be generated when +// exceptions are enabled. + +extern void bar(int); +void foo(int p) { + int a = 17; + bar(a); +} + +// CHECK: define {{.*}} @foo +// CHECK-NOT: personality +// CHECK: entry: +// CHECK: llvm.fake.use +// CHECK-NOT: landingpad diff --git a/clang/test/CodeGen/fake-use-noreturn.cpp b/clang/test/CodeGen/fake-use-noreturn.cpp new file mode 100644 index 00000000000000..acfcb0ce90b5e4 --- /dev/null +++ b/clang/test/CodeGen/fake-use-noreturn.cpp @@ -0,0 +1,27 @@ +// RUN: %clang %s -S -emit-llvm -fextend-lifetimes -O2 -o - -fno-discard-value-names | FileCheck %s +// +// Check we can correctly produce fake uses for function-level variables even +// when we have a return in a nested conditional and there is no code at the end +// of the function. + +// CHECK-LABEL: define{{.*}}@_Z3fooi +// CHECK: call{{.*}}llvm.fake.use(i32 %i) +// CHECK-LABEL: define{{.*}}@_ZN1C3barEi +// CHECK-DAG: call{{.*}}llvm.fake.use(i32 %i) +// CHECK-DAG: call{{.*}}llvm.fake.use({{.*}}%this) + +void foo(int i) { + while (0) + if (1) + return; +} + +class C { + void bar(int i); +}; + +void C::bar(int i) { + while (0) + if (1) + return; +} diff --git a/clang/test/CodeGen/fake-use-return-line.c b/clang/test/CodeGen/fake-use-return-line.c new file mode 100644 index 00000000000000..0c4377058d6628 --- /dev/null +++ b/clang/test/CodeGen/fake-use-return-line.c @@ -0,0 +1,15 @@ +// RUN: %clang_cc1 -emit-llvm -O2 -debug-info-kind=limited -fextend-lifetimes -o - %s | FileCheck %s + +// Clang adjusts the line numbers of returns based on the line numbers of +// dominating stores to %retval; we test that fake use intrinsics do not affect +// this, and the return is given the correct line. + +// CHECK: define{{.*}}@main +// CHECK: ret i32{{.*}}!dbg ![[MDINDEX:[0-9]*]] +// CHECK: ![[MDINDEX]] = !DILocation(line: [[# @LINE + 5]] +int main() +{ + volatile int a = 1; + int b = a + 2; + return b; +} diff --git a/clang/test/CodeGen/fake-use-sanitizer.cpp b/clang/test/CodeGen/fake-use-sanitizer.cpp new file mode 100644 index 00000000000000..915924a2b31025 --- /dev/null +++ b/clang/test/CodeGen/fake-use-san... [truncated] `````````` </details> https://github.com/llvm/llvm-project/pull/110102 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
