[llvm] r190407 - [asan] refactor the use-after-return API so that the size class is computed at compile time instead of at run-time. llvm part
Kostya Serebryany
kcc at google.com
Tue Sep 10 06:16:57 PDT 2013
Author: kcc
Date: Tue Sep 10 08:16:56 2013
New Revision: 190407
URL: http://llvm.org/viewvc/llvm-project?rev=190407&view=rev
Log:
[asan] refactor the use-after-return API so that the size class is computed at compile time instead of at run-time. llvm part
Modified:
llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
Modified: llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp?rev=190407&r1=190406&r2=190407&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/AddressSanitizer.cpp Tue Sep 10 08:16:56 2013
@@ -59,6 +59,7 @@ static const uint64_t kDefaultShort64bit
static const uint64_t kPPC64_ShadowOffset64 = 1ULL << 41;
static const uint64_t kMIPS32_ShadowOffset32 = 0x0aaa8000;
+static const size_t kMinStackMallocSize = 1 << 6; // 64B
static const size_t kMaxStackMallocSize = 1 << 16; // 64K
static const uintptr_t kCurrentStackFrameMagic = 0x41B58AB3;
static const uintptr_t kRetiredStackFrameMagic = 0x45E0360E;
@@ -78,8 +79,9 @@ static const char *const kAsanInitName =
static const char *const kAsanHandleNoReturnName = "__asan_handle_no_return";
static const char *const kAsanMappingOffsetName = "__asan_mapping_offset";
static const char *const kAsanMappingScaleName = "__asan_mapping_scale";
-static const char *const kAsanStackMallocName = "__asan_stack_malloc";
-static const char *const kAsanStackFreeName = "__asan_stack_free";
+static const int kMaxAsanStackMallocSizeClass = 10;
+static const char *const kAsanStackMallocNameTemplate = "__asan_stack_malloc_";
+static const char *const kAsanStackFreeNameTemplate = "__asan_stack_free_";
static const char *const kAsanGenPrefix = "__asan_gen_";
static const char *const kAsanPoisonStackMemoryName =
"__asan_poison_stack_memory";
@@ -396,7 +398,8 @@ struct FunctionStackPoisoner : public In
uint64_t TotalStackSize;
unsigned StackAlignment;
- Function *AsanStackMallocFunc, *AsanStackFreeFunc;
+ Function *AsanStackMallocFunc[kMaxAsanStackMallocSizeClass + 1],
+ *AsanStackFreeFunc[kMaxAsanStackMallocSizeClass + 1];
Function *AsanPoisonStackMemoryFunc, *AsanUnpoisonStackMemoryFunc;
// Stores a place and arguments of poisoning/unpoisoning call for alloca.
@@ -1271,11 +1274,15 @@ bool AddressSanitizer::LooksLikeCodeInBu
void FunctionStackPoisoner::initializeCallbacks(Module &M) {
IRBuilder<> IRB(*C);
- AsanStackMallocFunc = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanStackMallocName, IntptrTy, IntptrTy, IntptrTy, NULL));
- AsanStackFreeFunc = checkInterfaceFunction(M.getOrInsertFunction(
- kAsanStackFreeName, IRB.getVoidTy(),
- IntptrTy, IntptrTy, IntptrTy, NULL));
+ for (int i = 0; i <= kMaxAsanStackMallocSizeClass; i++) {
+ std::string Suffix = itostr(i);
+ AsanStackMallocFunc[i] = checkInterfaceFunction(
+ M.getOrInsertFunction(kAsanStackMallocNameTemplate + Suffix, IntptrTy,
+ IntptrTy, IntptrTy, NULL));
+ AsanStackFreeFunc[i] = checkInterfaceFunction(M.getOrInsertFunction(
+ kAsanStackFreeNameTemplate + Suffix, IRB.getVoidTy(), IntptrTy,
+ IntptrTy, IntptrTy, NULL));
+ }
AsanPoisonStackMemoryFunc = checkInterfaceFunction(M.getOrInsertFunction(
kAsanPoisonStackMemoryName, IRB.getVoidTy(), IntptrTy, IntptrTy, NULL));
AsanUnpoisonStackMemoryFunc = checkInterfaceFunction(M.getOrInsertFunction(
@@ -1344,12 +1351,24 @@ void FunctionStackPoisoner::poisonRedZon
}
}
+// Fake stack allocator (asan_fake_stack.h) has 11 size classes
+// for every power of 2 from kMinStackMallocSize to kMaxAsanStackMallocSizeClass
+static int StackMallocSizeClass(uint64_t LocalStackSize) {
+ assert(LocalStackSize <= kMaxStackMallocSize);
+ uint64_t MaxSize = kMinStackMallocSize;
+ for (int i = 0; ; i++, MaxSize *= 2)
+ if (LocalStackSize <= MaxSize)
+ return i;
+ llvm_unreachable("impossible LocalStackSize");
+}
+
void FunctionStackPoisoner::poisonStack() {
uint64_t LocalStackSize = TotalStackSize +
(AllocaVec.size() + 1) * RedzoneSize();
bool DoStackMalloc = ASan.CheckUseAfterReturn
&& LocalStackSize <= kMaxStackMallocSize;
+ int StackMallocIdx = -1;
assert(AllocaVec.size() > 0);
Instruction *InsBefore = AllocaVec[0];
@@ -1367,7 +1386,9 @@ void FunctionStackPoisoner::poisonStack(
Value *LocalStackBase = OrigStackBase;
if (DoStackMalloc) {
- LocalStackBase = IRB.CreateCall2(AsanStackMallocFunc,
+ StackMallocIdx = StackMallocSizeClass(LocalStackSize);
+ assert(StackMallocIdx <= kMaxAsanStackMallocSizeClass);
+ LocalStackBase = IRB.CreateCall2(AsanStackMallocFunc[StackMallocIdx],
ConstantInt::get(IntptrTy, LocalStackSize), OrigStackBase);
}
@@ -1442,8 +1463,9 @@ void FunctionStackPoisoner::poisonStack(
// Unpoison the stack.
poisonRedZones(AllocaVec, IRBRet, ShadowBase, false);
if (DoStackMalloc) {
+ assert(StackMallocIdx >= 0);
// In use-after-return mode, mark the whole stack frame unaddressable.
- IRBRet.CreateCall3(AsanStackFreeFunc, LocalStackBase,
+ IRBRet.CreateCall3(AsanStackFreeFunc[StackMallocIdx], LocalStackBase,
ConstantInt::get(IntptrTy, LocalStackSize),
OrigStackBase);
} else if (HavePoisonedAllocas) {
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