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[asan] Add flag to allow lifetime analysis of problematic allocas 

Summary:
Could be useful for comparison when we suspect that alloca was skipped
because of this.

Reviewers: eugenis

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D24437

llvm-svn: 281126
This commit is contained in:
Vitaly Buka 2016-09-10 01:06:11 +00:00
parent d98cf00c95
commit 3ac3aa50f6
2 changed files with 15 additions and 6 deletions
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6
llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
View File

@ -183,6 +183,10 @@ static cl::opt<bool> ClExperimentalPoisoning(
"asan-experimental-poisoning",
cl::desc("Enable experimental red zones and scope poisoning"), cl::Hidden,
cl::init(true));
static cl::opt<bool> ClSkipAmbiguousLifetimeAllocas(
"asan-skip-ambiguous-lifetime-allocas",
cl::desc("Disabled lifetime check for allocas with ambiguous lifetime"),
cl::Hidden, cl::init(true));
// This flag may need to be replaced with -f[no]asan-globals.
static cl::opt<bool> ClGlobals("asan-globals",
cl::desc("Handle global objects"), cl::Hidden,
@ -890,6 +894,8 @@ public:
// This is workaround for PR28267.
void removeAllocasWithAmbiguousLifetime(
SmallVectorImpl<FunctionStackPoisoner::AllocaPoisonCall> &PoisonCallVec) {
if (!ClSkipAmbiguousLifetimeAllocas)
return;
DenseMap<const AllocaInst *, AllocaLifetimeChecker> Checkers;
for (const auto &APC : PoisonCallVec)
Checkers[APC.AI].AddMarker(APC.InsBefore->getParent(), !APC.DoPoison);

15
llvm/test/Instrumentation/AddressSanitizer/lifetime.ll
View File

@ -1,6 +1,7 @@
; Test handling of llvm.lifetime intrinsics.
; RUN: opt < %s -asan -asan-module -asan-use-after-scope -asan-use-after-return=0 -S | FileCheck %s
; RUN: opt < %s -asan -asan-module -asan-use-after-scope -asan-use-after-return=0 -asan-instrument-dynamic-allocas=0 -S | FileCheck %s --check-prefix=CHECK-NO-DYNAMIC
; RUN: opt < %s -asan -asan-module -asan-use-after-scope -asan-use-after-return=0 -S | FileCheck %s --check-prefixes=CHECK,CHECK-DEFAULT
; RUN: opt < %s -asan -asan-module -asan-use-after-scope -asan-use-after-return=0 -asan-instrument-dynamic-allocas=0 -S | FileCheck %s --check-prefixes=CHECK,CHECK-NO-DYNAMIC
; RUN: opt < %s -asan -asan-module -asan-use-after-scope -asan-use-after-return=0 -asan-skip-ambiguous-lifetime-allocas=0 -S | FileCheck %s --check-prefixes=CHECK,CHECK-AMBIGUOUS
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"
@ -69,14 +70,14 @@ define void @lifetime() sanitize_address {
%arr.ptr = bitcast [10 x i32]* %arr to i8*
call void @llvm.lifetime.start(i64 40, i8* %arr.ptr)
; CHECK: call void @__asan_unpoison_stack_memory(i64 %{{[^ ]+}}, i64 40)
; CHECK-DEFAULT: call void @__asan_unpoison_stack_memory(i64 %{{[^ ]+}}, i64 40)
; CHECK-NO-DYNAMIC-NOT: call void @__asan_unpoison_stack_memory(i64 %{{[^ ]+}}, i64 40)
store volatile i8 0, i8* %arr.ptr
; CHECK: store volatile
call void @llvm.lifetime.end(i64 40, i8* %arr.ptr)
; CHECK: call void @__asan_poison_stack_memory(i64 %{{[^ ]+}}, i64 40)
; CHECK-DEFAULT: call void @__asan_poison_stack_memory(i64 %{{[^ ]+}}, i64 40)
; CHECK-NO-DYNAMIC-NOT: call void @__asan_poison_stack_memory(i64 %{{[^ ]+}}, i64 40)
; One more lifetime start/end for the same variable %i.
@ -116,7 +117,8 @@ bb0:
; CHECK-LABEL: bb0:
call void @llvm.lifetime.start(i64 1, i8* %j)
; CHECK-NOT: store i8 1, i8* %{{[0-9]+}}
; CHECK-DEFAULT-NOT: store i8 1, i8* %{{[0-9]+}}
; CHECK-AMBIGUOUS: store i8 1, i8* %{{[0-9]+}}
; CHECK-NEXT: call void @llvm.lifetime.start
br label %bb1
@ -132,7 +134,8 @@ bb1:
; CHECK-NEXT: call void @llvm.lifetime.end
call void @llvm.lifetime.end(i64 1, i8* %j)
; CHECK-NOT: store i8 -8, i8* %{{[0-9]+}}
; CHECK-DEFAULT-NOT: store i8 -8, i8* %{{[0-9]+}}
; CHECK-AMBIGUOUS: store i8 -8, i8* %{{[0-9]+}}
; CHECK-NEXT: call void @llvm.lifetime.end
ret void