3c6c14d14b
The function stack poisioner conditionally stores local variables either in an alloca or in malloc'ated memory, which has the unfortunate side-effect, that the actual address of the variable is only materialized when the variable is accessed, which means that those variables are mostly invisible to the debugger even when compiling without optimizations. This patch stores the address of the local stack base into an alloca, which can be referred to by the debug info and is available throughout the function. This adds one extra pointer-sized alloca to each stack frame (but mem2reg can optimize it away again when optimizations are enabled, yielding roughly the same debug info quality as before in optimized code). rdar://problem/30433661 Differential Revision: https://reviews.llvm.org/D41034 llvm-svn: 320415
55 lines
2.4 KiB
LLVM
55 lines
2.4 KiB
LLVM
; RUN: opt -S -asan -asan-skip-promotable-allocas=0 %s -o - | FileCheck %s
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; Generated from:
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; int bar(int y) {
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; return y + 2;
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; }
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source_filename = "/tmp/t.c"
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target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-apple-macosx10.13.0"
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; Function Attrs: noinline nounwind optnone sanitize_address ssp uwtable
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define i32 @foo(i32 %i) #0 !dbg !8 {
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entry:
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%i.addr = alloca i32, align 4
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store i32 %i, i32* %i.addr, align 4
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call void @llvm.dbg.declare(metadata i32* %i.addr, metadata !12, metadata !DIExpression()), !dbg !13
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; CHECK: %asan_local_stack_base = alloca i64
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; CHECK: %[[ALLOCA:.*]] = ptrtoint i8* %MyAlloca to i64
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; CHECK: %[[PHI:.*]] = phi i64 {{.*}} %[[ALLOCA]],
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; CHECK: store i64 %[[PHI]], i64* %asan_local_stack_base, !dbg
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; CHECK: call void @llvm.dbg.declare(metadata i64* %asan_local_stack_base, metadata !13, metadata !DIExpression(DW_OP_deref, DW_OP_plus_uconst, 32)), !dbg !14
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%0 = load i32, i32* %i.addr, align 4, !dbg !14
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%add = add nsw i32 %0, 2, !dbg !15
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ret i32 %add, !dbg !16
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}
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; Function Attrs: nounwind readnone speculatable
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declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
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attributes #0 = { noinline nounwind optnone sanitize_address ssp uwtable }
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attributes #1 = { nounwind readnone speculatable }
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!3, !4, !5, !6}
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!llvm.ident = !{!7}
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!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0 (trunk 320115) (llvm/trunk 320116)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
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!1 = !DIFile(filename: "/tmp/t.c", directory: "/Data/llvm")
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!2 = !{}
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!3 = !{i32 2, !"Dwarf Version", i32 4}
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!4 = !{i32 2, !"Debug Info Version", i32 3}
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!5 = !{i32 1, !"wchar_size", i32 4}
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!6 = !{i32 7, !"PIC Level", i32 2}
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!7 = !{!"clang version 6.0.0 (trunk 320115) (llvm/trunk 320116)"}
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!8 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 1, type: !9, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
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!9 = !DISubroutineType(types: !10)
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!10 = !{!11, !11}
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!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!12 = !DILocalVariable(name: "i", arg: 1, scope: !8, file: !1, line: 1, type: !11)
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!13 = !DILocation(line: 1, column: 13, scope: !8)
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!14 = !DILocation(line: 2, column: 10, scope: !8)
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!15 = !DILocation(line: 2, column: 12, scope: !8)
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!16 = !DILocation(line: 2, column: 3, scope: !8)
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