[llvm] r199488 - [asan] extend asan-coverage (still experimental).
Kostya Serebryany
kcc at google.com
Fri Jan 17 03:00:31 PST 2014
Author: kcc
Date: Fri Jan 17 05:00:30 2014
New Revision: 199488
URL: http://llvm.org/viewvc/llvm-project?rev=199488&view=rev
Log:
[asan] extend asan-coverage (still experimental).
- add a mode for collecting per-block coverage (-asan-coverage=2).
So far the implementation is naive (all blocks are instrumented),
the performance overhead on top of asan could be as high as 30%.
- Make sure the one-time calls to __sanitizer_cov are moved to function buttom,
which in turn required to copy the original debug info into the call insn.
Here is the performance data on SPEC 2006
(train data, comparing asan with asan-coverage={0,1,2}):
asan+cov0 asan+cov1 diff 0-1 asan+cov2 diff 0-2 diff 1-2
400.perlbench, 65.60, 65.80, 1.00, 76.20, 1.16, 1.16
401.bzip2, 65.10, 65.50, 1.01, 75.90, 1.17, 1.16
403.gcc, 1.64, 1.69, 1.03, 2.04, 1.24, 1.21
429.mcf, 21.90, 22.60, 1.03, 23.20, 1.06, 1.03
445.gobmk, 166.00, 169.00, 1.02, 205.00, 1.23, 1.21
456.hmmer, 88.30, 87.90, 1.00, 91.00, 1.03, 1.04
458.sjeng, 210.00, 222.00, 1.06, 258.00, 1.23, 1.16
462.libquantum, 1.73, 1.75, 1.01, 2.11, 1.22, 1.21
464.h264ref, 147.00, 152.00, 1.03, 160.00, 1.09, 1.05
471.omnetpp, 115.00, 116.00, 1.01, 140.00, 1.22, 1.21
473.astar, 133.00, 131.00, 0.98, 142.00, 1.07, 1.08
483.xalancbmk, 118.00, 120.00, 1.02, 154.00, 1.31, 1.28
433.milc, 19.80, 20.00, 1.01, 20.10, 1.02, 1.01
444.namd, 16.20, 16.20, 1.00, 17.60, 1.09, 1.09
447.dealII, 41.80, 42.20, 1.01, 43.50, 1.04, 1.03
450.soplex, 7.51, 7.82, 1.04, 8.25, 1.10, 1.05
453.povray, 14.00, 14.40, 1.03, 15.80, 1.13, 1.10
470.lbm, 33.30, 34.10, 1.02, 34.10, 1.02, 1.00
482.sphinx3, 12.40, 12.30, 0.99, 13.00, 1.05, 1.06
Modified:
llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
llvm/trunk/test/Instrumentation/AddressSanitizer/coverage.ll
Modified: llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp?rev=199488&r1=199487&r2=199488&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp Fri Jan 17 05:00:30 2014
@@ -33,6 +33,7 @@
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/InstVisitor.h"
@@ -130,8 +131,9 @@ static cl::opt<bool> ClUseAfterReturn("a
// 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, cl::init(true));
-static cl::opt<bool> ClCoverage("asan-coverage",
- cl::desc("ASan coverage"), cl::Hidden, cl::init(false));
+static cl::opt<int> ClCoverage("asan-coverage",
+ cl::desc("ASan coverage. 0: none, 1: entry block, 2: all blocks"),
+ cl::Hidden, cl::init(false));
static cl::opt<bool> ClInitializers("asan-initialization-order",
cl::desc("Handle C++ initializer order"), cl::Hidden, cl::init(false));
static cl::opt<bool> ClMemIntrin("asan-memintrin",
@@ -320,7 +322,8 @@ struct AddressSanitizer : public Functio
bool LooksLikeCodeInBug11395(Instruction *I);
void FindDynamicInitializers(Module &M);
bool GlobalIsLinkerInitialized(GlobalVariable *G);
- bool InjectCoverage(Function &F);
+ bool InjectCoverage(Function &F, const ArrayRef<BasicBlock*> AllBlocks);
+ void InjectCoverageAtBlock(Function &F, BasicBlock &BB);
bool CheckInitOrder;
bool CheckUseAfterReturn;
@@ -1076,7 +1079,7 @@ void AddressSanitizer::initializeCallbac
AsanHandleNoReturnFunc = checkInterfaceFunction(M.getOrInsertFunction(
kAsanHandleNoReturnName, IRB.getVoidTy(), NULL));
AsanCovFunction = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanCovName, IRB.getVoidTy(), IntptrTy, NULL));
+ kAsanCovName, IRB.getVoidTy(), NULL));
// We insert an empty inline asm after __asan_report* to avoid callback merge.
EmptyAsm = InlineAsm::get(FunctionType::get(IRB.getVoidTy(), false),
StringRef(""), StringRef(""),
@@ -1148,33 +1151,11 @@ bool AddressSanitizer::maybeInsertAsanIn
return false;
}
-// Poor man's coverage that works with ASan.
-// We create a Guard boolean variable with the same linkage
-// as the function and inject this code into the entry block:
-// if (*Guard) {
-// __sanitizer_cov(&F);
-// *Guard = 1;
-// }
-// The accesses to Guard are atomic. The rest of the logic is
-// in __sanitizer_cov (it's fine to call it more than once).
-//
-// This coverage implementation provides very limited data:
-// it only tells if a given function was ever executed.
-// No counters, no per-basic-block or per-edge data.
-// But for many use cases this is what we need and the added slowdown
-// is negligible. This simple implementation will probably be obsoleted
-// by the upcoming Clang-based coverage implementation.
-// By having it here and now we hope to
-// a) get the functionality to users earlier and
-// b) collect usage statistics to help improve Clang coverage design.
-bool AddressSanitizer::InjectCoverage(Function &F) {
- if (!ClCoverage) return false;
-
+void AddressSanitizer::InjectCoverageAtBlock(Function &F, BasicBlock &BB) {
+ BasicBlock::iterator IP = BB.getFirstInsertionPt(), BE = BB.end();
// Skip static allocas at the top of the entry block so they don't become
// dynamic when we split the block. If we used our optimized stack layout,
// then there will only be one alloca and it will come first.
- BasicBlock &Entry = F.getEntryBlock();
- BasicBlock::iterator IP = Entry.getFirstInsertionPt(), BE = Entry.end();
for (; IP != BE; ++IP) {
AllocaInst *AI = dyn_cast<AllocaInst>(IP);
if (!AI || !AI->isStaticAlloca())
@@ -1190,14 +1171,48 @@ bool AddressSanitizer::InjectCoverage(Fu
Load->setAtomic(Monotonic);
Load->setAlignment(1);
Value *Cmp = IRB.CreateICmpEQ(Constant::getNullValue(Int8Ty), Load);
- Instruction *Ins = SplitBlockAndInsertIfThen(Cmp, IP, false);
+ Instruction *Ins = SplitBlockAndInsertIfThen(
+ Cmp, IP, false, MDBuilder(*C).createBranchWeights(1, 100000));
IRB.SetInsertPoint(Ins);
// We pass &F to __sanitizer_cov. We could avoid this and rely on
// GET_CALLER_PC, but having the PC of the first instruction is just nice.
- IRB.CreateCall(AsanCovFunction, IRB.CreatePointerCast(&F, IntptrTy));
+ Instruction *Call = IRB.CreateCall(AsanCovFunction);
+ Call->setDebugLoc(IP->getDebugLoc());
StoreInst *Store = IRB.CreateStore(ConstantInt::get(Int8Ty, 1), Guard);
Store->setAtomic(Monotonic);
Store->setAlignment(1);
+}
+
+// Poor man's coverage that works with ASan.
+// We create a Guard boolean variable with the same linkage
+// as the function and inject this code into the entry block (-asan-coverage=1)
+// or all blocks (-asan-coverage=2):
+// if (*Guard) {
+// __sanitizer_cov(&F);
+// *Guard = 1;
+// }
+// The accesses to Guard are atomic. The rest of the logic is
+// in __sanitizer_cov (it's fine to call it more than once).
+//
+// This coverage implementation provides very limited data:
+// it only tells if a given function (block) was ever executed.
+// No counters, no per-edge data.
+// But for many use cases this is what we need and the added slowdown
+// is negligible. This simple implementation will probably be obsoleted
+// by the upcoming Clang-based coverage implementation.
+// By having it here and now we hope to
+// a) get the functionality to users earlier and
+// b) collect usage statistics to help improve Clang coverage design.
+bool AddressSanitizer::InjectCoverage(Function &F,
+ const ArrayRef<BasicBlock *> AllBlocks) {
+ if (!ClCoverage) return false;
+
+ if (ClCoverage == 1) {
+ InjectCoverageAtBlock(F, F.getEntryBlock());
+ } else {
+ for (size_t i = 0, n = AllBlocks.size(); i < n; i++)
+ InjectCoverageAtBlock(F, *AllBlocks[i]);
+ }
return true;
}
@@ -1222,12 +1237,14 @@ bool AddressSanitizer::runOnFunction(Fun
SmallSet<Value*, 16> TempsToInstrument;
SmallVector<Instruction*, 16> ToInstrument;
SmallVector<Instruction*, 8> NoReturnCalls;
+ SmallVector<BasicBlock*, 16> AllBlocks;
int NumAllocas = 0;
bool IsWrite;
// Fill the set of memory operations to instrument.
for (Function::iterator FI = F.begin(), FE = F.end();
FI != FE; ++FI) {
+ AllBlocks.push_back(FI);
TempsToInstrument.clear();
int NumInsnsPerBB = 0;
for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
@@ -1297,7 +1314,7 @@ bool AddressSanitizer::runOnFunction(Fun
bool res = NumInstrumented > 0 || ChangedStack || !NoReturnCalls.empty();
- if (InjectCoverage(F))
+ if (InjectCoverage(F, AllBlocks))
res = true;
DEBUG(dbgs() << "ASAN done instrumenting: " << res << " " << F << "\n");
Modified: llvm/trunk/test/Instrumentation/AddressSanitizer/coverage.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Instrumentation/AddressSanitizer/coverage.ll?rev=199488&r1=199487&r2=199488&view=diff
==============================================================================
--- llvm/trunk/test/Instrumentation/AddressSanitizer/coverage.ll (original)
+++ llvm/trunk/test/Instrumentation/AddressSanitizer/coverage.ll Fri Jan 17 05:00:30 2014
@@ -1,13 +1,30 @@
-; RUN: opt < %s -asan -asan-coverage=1 -S | FileCheck %s
+; RUN: opt < %s -asan -asan-coverage=1 -S | FileCheck %s --check-prefix=CHECK1
+; RUN: opt < %s -asan -asan-coverage=2 -S | FileCheck %s --check-prefix=CHECK2
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"
target triple = "x86_64-unknown-linux-gnu"
-define i32 @foo(i32* %a) sanitize_address {
+define void @foo(i32* %a) sanitize_address {
entry:
- ret i32 0
+ %tobool = icmp eq i32* %a, null
+ br i1 %tobool, label %if.end, label %if.then
+
+ if.then: ; preds = %entry
+ store i32 0, i32* %a, align 4
+ br label %if.end
+
+ if.end: ; preds = %entry, %if.then
+ ret void
}
-; CHECK: define i32 @foo(i32* %a) #0 {
-; CHECK: %0 = load atomic i8* @__asan_gen_cov_foo monotonic, align 1
-; CHECK: %1 = icmp eq i8 0, %0
-; CHECK: br i1 %1, label %2, label %3
-; CHECK: call void @__sanitizer_cov(i64 ptrtoint (i32 (i32*)* @foo to i64))
-; CHECK: store atomic i8 1, i8* @__asan_gen_cov_foo monotonic, align 1
+; CHECK1-LABEL: define void @foo
+; CHECK1: %0 = load atomic i8* @__asan_gen_cov_foo monotonic, align 1
+; CHECK1: %1 = icmp eq i8 0, %0
+; CHECK1: br i1 %1, label %2, label %3
+; CHECK1: call void @__sanitizer_cov
+; CHECK1-NOT: call void @__sanitizer_cov
+; CHECK1: store atomic i8 1, i8* @__asan_gen_cov_foo monotonic, align 1
+
+; CHECK2-LABEL: define void @foo
+; CHECK2: call void @__sanitizer_cov
+; CHECK2: call void @__sanitizer_cov
+; CHECK2: call void @__sanitizer_cov
+; CHECK2-NOT: call void @__sanitizer_cov
+; CHECK2: ret void
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