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[asan] make sure that linker-initialized globals (non-extern) are not instrumented even in -asan-initialization-order mode. This time with a test

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168366 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Kostya Serebryany 2012-11-20 13:00:01 +00:00
parent 426fe8b83a
commit ca23d43084
2 changed files with 51 additions and 32 deletions
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62
lib/Transforms/Instrumentation/AddressSanitizer.cpp
View File

@ -148,6 +148,32 @@ static cl::opt<int> ClDebugMax("asan-debug-max", cl::desc("Debug man inst"),
cl::Hidden, cl::init(-1));
namespace {
/// A set of dynamically initialized globals extracted from metadata.
class SetOfDynamicallyInitializedGlobals {
public:
void Init(Module& M) {
// Clang generates metadata identifying all dynamically initialized globals.
NamedMDNode *DynamicGlobals =
M.getNamedMetadata("llvm.asan.dynamically_initialized_globals");
if (!DynamicGlobals)
return;
for (int i = 0, n = DynamicGlobals->getNumOperands(); i < n; ++i) {
MDNode *MDN = DynamicGlobals->getOperand(i);
assert(MDN->getNumOperands() == 1);
Value *VG = MDN->getOperand(0);
// The optimizer may optimize away a global entirely, in which case we
// cannot instrument access to it.
if (!VG)
continue;
DynInitGlobals.insert(cast<GlobalVariable>(VG));
}
}
bool Contains(GlobalVariable *G) { return DynInitGlobals.count(G) != 0; }
private:
SmallSet<GlobalValue*, 32> DynInitGlobals;
};
/// AddressSanitizer: instrument the code in module to find memory bugs.
struct AddressSanitizer : public FunctionPass {
AddressSanitizer();
@ -195,7 +221,6 @@ struct AddressSanitizer : public FunctionPass {
Value *ShadowBase, bool DoPoison);
bool LooksLikeCodeInBug11395(Instruction *I);
void FindDynamicInitializers(Module &M);
bool HasDynamicInitializer(GlobalVariable *G);
LLVMContext *C;
DataLayout *TD;
@ -214,8 +239,8 @@ struct AddressSanitizer : public FunctionPass {
// This array is indexed by AccessIsWrite and log2(AccessSize).
Function *AsanErrorCallback[2][kNumberOfAccessSizes];
InlineAsm *EmptyAsm;
SmallSet<GlobalValue*, 32> DynamicallyInitializedGlobals;
SmallSet<GlobalValue*, 32> GlobalsCreatedByAsan;
SetOfDynamicallyInitializedGlobals DynamicallyInitializedGlobals;
};
} // namespace
@ -328,30 +353,6 @@ static Value *isInterestingMemoryAccess(Instruction *I, bool *IsWrite) {
return NULL;
}
void AddressSanitizer::FindDynamicInitializers(Module& M) {
// Clang generates metadata identifying all dynamically initialized globals.
NamedMDNode *DynamicGlobals =
M.getNamedMetadata("llvm.asan.dynamically_initialized_globals");
if (!DynamicGlobals)
return;
for (int i = 0, n = DynamicGlobals->getNumOperands(); i < n; ++i) {
MDNode *MDN = DynamicGlobals->getOperand(i);
assert(MDN->getNumOperands() == 1);
Value *VG = MDN->getOperand(0);
// The optimizer may optimize away a global entirely, in which case we
// cannot instrument access to it.
if (!VG)
continue;
GlobalVariable *G = cast<GlobalVariable>(VG);
DynamicallyInitializedGlobals.insert(G);
}
}
// Returns true if a global variable is initialized dynamically in this TU.
bool AddressSanitizer::HasDynamicInitializer(GlobalVariable *G) {
return DynamicallyInitializedGlobals.count(G);
}
void AddressSanitizer::instrumentMop(Instruction *I) {
bool IsWrite = false;
Value *Addr = isInterestingMemoryAccess(I, &IsWrite);
@ -367,7 +368,7 @@ void AddressSanitizer::instrumentMop(Instruction *I) {
// assume it has dynamic initialization, as it may have an initializer
// in a different TU.
if (G->getLinkage() != GlobalVariable::ExternalLinkage &&
!HasDynamicInitializer(G))
!DynamicallyInitializedGlobals.Contains(G))
return;
}
}
@ -590,9 +591,6 @@ bool AddressSanitizer::insertGlobalRedzones(Module &M) {
IRBuilder<> IRB(CtorInsertBefore);
if (ClInitializers)
FindDynamicInitializers(M);
// The addresses of the first and last dynamically initialized globals in
// this TU. Used in initialization order checking.
Value *FirstDynamic = 0, *LastDynamic = 0;
@ -606,7 +604,8 @@ bool AddressSanitizer::insertGlobalRedzones(Module &M) {
(RedzoneSize - (SizeInBytes % RedzoneSize));
Type *RightRedZoneTy = ArrayType::get(IRB.getInt8Ty(), RightRedzoneSize);
// Determine whether this global should be poisoned in initialization.
bool GlobalHasDynamicInitializer = HasDynamicInitializer(G);
bool GlobalHasDynamicInitializer =
DynamicallyInitializedGlobals.Contains(G);
// Don't check initialization order if this global is blacklisted.
GlobalHasDynamicInitializer &= !BL->isInInit(*G);
@ -704,6 +703,7 @@ bool AddressSanitizer::doInitialization(Module &M) {
if (!TD)
return false;
BL.reset(new BlackList(ClBlackListFile));
DynamicallyInitializedGlobals.Init(M);
C = &(M.getContext());
LongSize = TD->getPointerSizeInBits();

21
test/Instrumentation/AddressSanitizer/instrument_initializer_metadata.ll
View File

@ -1,7 +1,8 @@
; RUN: opt < %s -asan -asan-initialization-order -S | FileCheck %s
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"
@xxx = global i32 0, align 4
@xxx = internal global i32 0, align 4 ; With dynamic initializer.
@yyy = internal global i32 0, align 4 ; W/o dynamic initializer.
; Clang will emit the following metadata identifying @xxx as dynamically
; initialized.
!0 = metadata !{i32* @xxx}
@ -34,3 +35,21 @@ entry:
; CHECK: call void @__cxx_global_var_init
; CHECK: call void @__asan_after_dynamic_init
; CHECK: ret
; Check that xxx is instrumented.
define void @touch_xxx() address_safety {
store i32 0, i32 *@xxx, align 4
ret void
; CHECK: define void @touch_xxx
; CHECK: call void @__asan_report_store4
; CHECK: ret void
}
; Check that yyy is NOT instrumented (as it does not have dynamic initializer).
define void @touch_yyy() address_safety {
store i32 0, i32 *@yyy, align 4
ret void
; CHECK: define void @touch_yyy
; CHECK-NOT: call void @__asan_report_store4
; CHECK: ret void
}