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llvm-mirror/test/Instrumentation/AddressSanitizer/debug_info.ll
Adrian Prantl 5ae8c3d77e ASAN: Provide reliable debug info for local variables at -O0.
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
2017-12-11 20:43:21 +00:00

61 lines
3.1 KiB
LLVM

; RUN: opt < %s -asan -asan-module -asan-use-after-return=0 -S | FileCheck %s
; Checks that llvm.dbg.declare instructions are updated
; accordingly as we merge allocas.
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
target triple = "x86_64-unknown-linux-gnu"
define i32 @_Z3zzzi(i32 %p) nounwind uwtable sanitize_address !dbg !5 {
entry:
%p.addr = alloca i32, align 4
%r = alloca i32, align 4
store volatile i32 %p, i32* %p.addr, align 4
call void @llvm.dbg.declare(metadata i32* %p.addr, metadata !10, metadata !DIExpression()), !dbg !11
call void @llvm.dbg.declare(metadata i32* %r, metadata !12, metadata !DIExpression()), !dbg !14
%0 = load i32, i32* %p.addr, align 4, !dbg !14
%add = add nsw i32 %0, 1, !dbg !14
store volatile i32 %add, i32* %r, align 4, !dbg !14
%1 = load i32, i32* %r, align 4, !dbg !15
ret i32 %1, !dbg !15
}
; CHECK: define i32 @_Z3zzzi
; CHECK: entry:
; Verify that llvm.dbg.declare calls are in the entry basic block.
; CHECK-NOT: %entry
; CHECK: call void @llvm.dbg.declare(metadata {{.*}}, metadata ![[ARG_ID:[0-9]+]], metadata !DIExpression(DW_OP_plus_uconst, 32))
; CHECK-NOT: %entry
; CHECK: call void @llvm.dbg.declare(metadata {{.*}}, metadata ![[VAR_ID:[0-9]+]], metadata !DIExpression(DW_OP_plus_uconst, 48))
declare void @llvm.dbg.declare(metadata, metadata, metadata) nounwind readnone
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!17}
!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, producer: "clang version 3.3 (trunk 169314)", isOptimized: true, emissionKind: FullDebug, file: !16, enums: !1, retainedTypes: !1, globals: !1)
!1 = !{}
!5 = distinct !DISubprogram(name: "zzz", linkageName: "_Z3zzzi", line: 1, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !0, scopeLine: 1, file: !16, scope: !6, type: !7, variables: !1)
!6 = !DIFile(filename: "a.cc", directory: "/usr/local/google/llvm_cmake_clang/tmp/debuginfo")
!7 = !DISubroutineType(types: !8)
!8 = !{!9, !9}
!9 = !DIBasicType(tag: DW_TAG_base_type, name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
!10 = !DILocalVariable(name: "p", line: 1, arg: 1, scope: !5, file: !6, type: !9)
!11 = !DILocation(line: 1, scope: !5)
!12 = !DILocalVariable(name: "r", line: 2, scope: !13, file: !6, type: !9)
; Verify that debug descriptors for argument and local variable will be replaced
; with descriptors that end with OpDeref (encoded as 2).
; CHECK: ![[ARG_ID]] = !DILocalVariable(name: "p", arg: 1,{{.*}} line: 1
; CHECK: ![[VAR_ID]] = !DILocalVariable(name: "r",{{.*}} line: 2
; Verify that there are no more variable descriptors.
; CHECK-NOT: !DILocalVariable(tag: DW_TAG_arg_variable
; CHECK-NOT: !DILocalVariable(tag: DW_TAG_auto_variable
!13 = distinct !DILexicalBlock(line: 1, column: 0, file: !16, scope: !5)
!14 = !DILocation(line: 2, scope: !13)
!15 = !DILocation(line: 3, scope: !13)
!16 = !DIFile(filename: "a.cc", directory: "/usr/local/google/llvm_cmake_clang/tmp/debuginfo")
!17 = !{i32 1, !"Debug Info Version", i32 3}