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[DebugInfo] Fix incorrect debug attribution for inlined allocas #144345

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[DebugInfo] Fix incorrect debug attribution for inlined allocas #144345

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c7e92da
Fix incorrect debug attribution for inlined allocas
phyBrackets Jun 16, 2025
7de1b9a
Add test to verify the changes
phyBrackets Jun 16, 2025
8db557b
commit review feedback
phyBrackets Jun 20, 2025
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11 changes: 11 additions & 0 deletions llvm/lib/Transforms/Utils/InlineFunction.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2703,6 +2703,17 @@ llvm::InlineResult llvm::InlineFunction(CallBase &CB, InlineFunctionInfo &IFI,
// Remember the first block that is newly cloned over.
FirstNewBlock = LastBlock; ++FirstNewBlock;

// Clear debug locations for all inlined allocas to prevent stack protection
// code from inheriting incorrect source attribution.
for (Function::iterator BB = FirstNewBlock, E = Caller->end(); BB != E;
++BB) {
for (BasicBlock::iterator I = BB->begin(), IE = BB->end(); I != IE; ++I) {
if (auto *AI = dyn_cast<AllocaInst>(I)) {
AI->setDebugLoc(DebugLoc::getDropped());
}
}
}

// Insert retainRV/clainRV runtime calls.
objcarc::ARCInstKind RVCallKind = objcarc::getAttachedARCFunctionKind(&CB);
if (RVCallKind != objcarc::ARCInstKind::None)
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65 changes: 65 additions & 0 deletions llvm/test/Transforms/Inline/inline-alloca-debug-clear.ll
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@@ -0,0 +1,65 @@
; RUN: opt < %s -passes=always-inline -S | FileCheck %s
; Test that inlined allocas do not retain debug locations from the callee
; to prevent incorrect source attribution in generated code.

; ModuleID = 'test-inline-debug-alloca.c'
source_filename = "test-inline-debug-alloca.c"
target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"

; Function Attrs: alwaysinline nounwind uwtable
define dso_local i32 @callee() #0 !dbg !7 {
entry:
%large_array = alloca [1000 x i8], align 1, !dbg !12
%x = alloca i32, align 4, !dbg !13
%arrayidx = getelementptr inbounds [1000 x i8], ptr %large_array, i64 0, i64 0, !dbg !14
store i8 42, ptr %arrayidx, align 1, !dbg !15
store i32 123, ptr %x, align 4, !dbg !16
%0 = load i32, ptr %x, align 4, !dbg !17
ret i32 %0, !dbg !18
}

; Function Attrs: nounwind uwtable
define dso_local i32 @caller() #1 !dbg !19 {
entry:
%call = call i32 @callee(), !dbg !20
ret i32 %call, !dbg !21
}

; CHECK-LABEL: define dso_local i32 @caller()
; CHECK: entry:
; CHECK: %large_array.i = alloca [1000 x i8], align 1{{$}}
; CHECK-NOT: %large_array.i = alloca [1000 x i8], align 1, !dbg
; CHECK: %x.i = alloca i32, align 4{{$}}
; CHECK-NOT: %x.i = alloca i32, align 4, !dbg
; CHECK: ret i32

attributes #0 = { alwaysinline nounwind uwtable }
attributes #1 = { nounwind uwtable }

!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!2, !3, !4, !5}
!llvm.ident = !{!6}

!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false)
!1 = !DIFile(filename: "test-inline-debug-alloca.c", directory: "/tmp")
!2 = !{i32 7, !"Dwarf Version", i32 4}
!3 = !{i32 2, !"Debug Info Version", i32 3}
!4 = !{i32 1, !"wchar_size", i32 4}
!5 = !{i32 8, !"PIC Level", i32 2}
!6 = !{!"clang"}
!7 = distinct !DISubprogram(name: "callee", scope: !1, file: !1, line: 1, type: !8, scopeLine: 1, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !11)
!8 = !DISubroutineType(types: !9)
!9 = !{!10}
!10 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
!11 = !{}
!12 = !DILocation(line: 2, column: 9, scope: !7)
!13 = !DILocation(line: 3, column: 9, scope: !7)
!14 = !DILocation(line: 4, column: 3, scope: !7)
!15 = !DILocation(line: 4, column: 16, scope: !7)
!16 = !DILocation(line: 5, column: 5, scope: !7)
!17 = !DILocation(line: 6, column: 10, scope: !7)
!18 = !DILocation(line: 6, column: 3, scope: !7)
!19 = distinct !DISubprogram(name: "caller", scope: !1, file: !1, line: 9, type: !8, scopeLine: 9, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !11)
!20 = !DILocation(line: 10, column: 10, scope: !19)
!21 = !DILocation(line: 10, column: 3, scope: !19)
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