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[asan] Speed up compilation of large C++ stringmaps (tons of allocas) with ASan

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This addresses PR30746, <https://llvm.org/bugs/show_bug.cgi?id=30746>. The ASan pass iterates over entry-block instructions and checks each alloca whether it's in NonInstrumentedStaticAllocaVec, which is apparently slow. This patch gathers the instructions to move during visitAllocaInst.

Differential Revision: https://reviews.llvm.org/D26380



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286296 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Kuba Brecka 2016-11-08 21:30:41 +00:00
parent 665c3d9425
commit 4f349ace2b
2 changed files with 33 additions and 6 deletions
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18
lib/Transforms/Instrumentation/AddressSanitizer.cpp
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@ -638,7 +638,7 @@ struct FunctionStackPoisoner : public InstVisitor<FunctionStackPoisoner> {
ShadowMapping Mapping;
SmallVector<AllocaInst *, 16> AllocaVec;
SmallSetVector<AllocaInst *, 16> NonInstrumentedStaticAllocaVec;
SmallVector<AllocaInst *, 16> StaticAllocasToMoveUp;
SmallVector<Instruction *, 8> RetVec;
unsigned StackAlignment;
@ -766,7 +766,14 @@ struct FunctionStackPoisoner : public InstVisitor<FunctionStackPoisoner> {
/// \brief Collect Alloca instructions we want (and can) handle.
void visitAllocaInst(AllocaInst &AI) {
if (!ASan.isInterestingAlloca(AI)) {
if (AI.isStaticAlloca()) NonInstrumentedStaticAllocaVec.insert(&AI);
if (AI.isStaticAlloca()) {
// Skip over allocas that are present *before* the first instrumented
// alloca, we don't want to move those around.
if (AllocaVec.empty())
return;
StaticAllocasToMoveUp.push_back(&AI);
}
return;
}
@ -2231,10 +2238,9 @@ void FunctionStackPoisoner::processStaticAllocas() {
// regular stack slots.
auto InsBeforeB = InsBefore->getParent();
assert(InsBeforeB == &F.getEntryBlock());
for (BasicBlock::iterator I(InsBefore); I != InsBeforeB->end(); ++I)
if (auto *AI = dyn_cast<AllocaInst>(I))
if (NonInstrumentedStaticAllocaVec.count(AI) > 0)
AI->moveBefore(InsBefore);
for (auto *AI : StaticAllocasToMoveUp)
if (AI->getParent() == InsBeforeB)
AI->moveBefore(InsBefore);
// If we have a call to llvm.localescape, keep it in the entry block.
if (LocalEscapeCall) LocalEscapeCall->moveBefore(InsBefore);

21
test/Instrumentation/AddressSanitizer/debug_info_noninstrumented_alloca2.ll Normal file
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@ -0,0 +1,21 @@
; Make sure we don't break the IR when moving non-instrumented allocas
; RUN: opt < %s -asan -asan-module -S | FileCheck %s
; RUN: opt < %s -asan -asan-module -asan-instrument-dynamic-allocas -S | FileCheck %s
target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
target triple = "x86_64-apple-macosx10.10.0"
define i32 @foo() sanitize_address {
entry:
%non_instrumented1 = alloca i32, align 4
%t = load i32, i32* %non_instrumented1, align 4
%instrumented = alloca i32, align 4
%ptr = ptrtoint i32* %instrumented to i32
ret i32 %t
}
; CHECK: entry:
; CHECK: %non_instrumented1 = alloca i32, align 4
; CHECK: load i32, i32* %non_instrumented1
; CHECK: load i32, i32* @__asan_option_detect_stack_use_after_return