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Differential D158972

[DebugInfo] Fix incorrect dbg.declare when nrvo flag is used
ClosedPublic

Authored by nikic on Aug 28 2023, 2:42 AM.

Details

Reviewers
aprantl
Group Reviewers
debug-info
Commits
rG13a044c6993a: [DebugInfo] Fix incorrect dbg.declare when nrvo flag is used
Summary

When clang generates an nrvo boolean flag, the dbg.declare for the corresponding variable was incorrectly placed on that flag, rather than the actual variable.

Fix this by not overwriting AllocaAddr with the nrvo flag.

This started causing verifier errors with D158743.

Diff Detail

Revision Contents

PathSize
clang/
lib/
CodeGen/
3 lines
test/
CodeGenCXX/
33 lines

Diff 554227

clang/lib/CodeGen/CGDecl.cpp

Show First 20 Lines • Show All 1,528 Lines • ▼ Show 20 Lines if (NRVO) {
const auto *CXXRD = dyn_cast<CXXRecordDecl>(RD); const auto *CXXRD = dyn_cast<CXXRecordDecl>(RD);
if ((CXXRD && !CXXRD->hasTrivialDestructor()) || if ((CXXRD && !CXXRD->hasTrivialDestructor()) ||
RD->isNonTrivialToPrimitiveDestroy()) { RD->isNonTrivialToPrimitiveDestroy()) {
// Create a flag that is used to indicate when the NRVO was applied // Create a flag that is used to indicate when the NRVO was applied
// to this variable. Set it to zero to indicate that NRVO was not // to this variable. Set it to zero to indicate that NRVO was not
// applied. // applied.
llvm::Value *Zero = Builder.getFalse(); llvm::Value *Zero = Builder.getFalse();
Address NRVOFlag = Address NRVOFlag =
CreateTempAlloca(Zero->getType(), CharUnits::One(), "nrvo", CreateTempAlloca(Zero->getType(), CharUnits::One(), "nrvo");
/*ArraySize=*/nullptr, &AllocaAddr);
EnsureInsertPoint(); EnsureInsertPoint();
Builder.CreateStore(Zero, NRVOFlag); Builder.CreateStore(Zero, NRVOFlag);
// Record the NRVO flag for this variable. // Record the NRVO flag for this variable.
NRVOFlags[&D] = NRVOFlag.getPointer(); NRVOFlags[&D] = NRVOFlag.getPointer();
emission.NRVOFlag = NRVOFlag.getPointer(); emission.NRVOFlag = NRVOFlag.getPointer();
} }
} }
▲ Show 20 Lines • Show All 1,243 Lines • Show Last 20 Lines

clang/test/CodeGenCXX/trivial_abi_debuginfo.cpp

  • This file was added.
// NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --functions "makeTrivial" --version 2
// RUN: %clang_cc1 -debug-info-kind=limited -triple x86_64-unknown-linux-gnu -emit-llvm -o - %s | FileCheck %s
struct __attribute__((trivial_abi)) Trivial {
~Trivial() {}
int ivar = 10;
};
// The dbg.declare should be on %retval, not on %nrvo.
// CHECK-LABEL: define dso_local i32 @_Z11makeTrivialv
// CHECK-SAME: () #[[ATTR0:[0-9]+]] !dbg [[DBG5:![0-9]+]] {
// CHECK-NEXT: entry:
// CHECK-NEXT: [[RETVAL:%.*]] = alloca [[STRUCT_TRIVIAL:%.*]], align 4
// CHECK-NEXT: [[NRVO:%.*]] = alloca i1, align 1
// CHECK-NEXT: store i1 false, ptr [[NRVO]], align 1, !dbg [[DBG18:![0-9]+]]
// CHECK-NEXT: call void @llvm.dbg.declare(metadata ptr [[RETVAL]], metadata [[META19:![0-9]+]], metadata !DIExpression()), !dbg [[DBG20:![0-9]+]]
// CHECK-NEXT: call void @_ZN7TrivialC1Ev(ptr noundef nonnull align 4 dereferenceable(4) [[RETVAL]]) #[[ATTR3:[0-9]+]], !dbg [[DBG20]]
// CHECK-NEXT: store i1 true, ptr [[NRVO]], align 1, !dbg [[DBG21:![0-9]+]]
// CHECK-NEXT: [[NRVO_VAL:%.*]] = load i1, ptr [[NRVO]], align 1, !dbg [[DBG22:![0-9]+]]
// CHECK-NEXT: br i1 [[NRVO_VAL]], label [[NRVO_SKIPDTOR:%.*]], label [[NRVO_UNUSED:%.*]], !dbg [[DBG22]]
// CHECK: nrvo.unused:
// CHECK-NEXT: call void @_ZN7TrivialD1Ev(ptr noundef nonnull align 4 dereferenceable(4) [[RETVAL]]) #[[ATTR3]], !dbg [[DBG22]]
// CHECK-NEXT: br label [[NRVO_SKIPDTOR]], !dbg [[DBG22]]
// CHECK: nrvo.skipdtor:
// CHECK-NEXT: [[COERCE_DIVE:%.*]] = getelementptr inbounds [[STRUCT_TRIVIAL]], ptr [[RETVAL]], i32 0, i32 0, !dbg [[DBG22]]
// CHECK-NEXT: [[TMP0:%.*]] = load i32, ptr [[COERCE_DIVE]], align 4, !dbg [[DBG22]]
// CHECK-NEXT: ret i32 [[TMP0]], !dbg [[DBG22]]
//
Trivial makeTrivial() {
Trivial ret_val;
return ret_val;
}