================
@@ -1078,22 +1091,61 @@ void
ModuleSanitizerCoverage::InjectCoverageAtBlock(Function &F, BasicBlock &BB,
Store->setNoSanitizeMetadata();
}
if (Options.StackDepth && IsEntryBB && !IsLeafFunc) {
- // Check stack depth. If it's the deepest so far, record it.
Module *M = F.getParent();
- auto FrameAddrPtr = IRB.CreateIntrinsic(
- Intrinsic::frameaddress,
- IRB.getPtrTy(M->getDataLayout().getAllocaAddrSpace()),
- {Constant::getNullValue(Int32Ty)});
- auto FrameAddrInt = IRB.CreatePtrToInt(FrameAddrPtr, IntptrTy);
- auto LowestStack = IRB.CreateLoad(IntptrTy, SanCovLowestStack);
- auto IsStackLower = IRB.CreateICmpULT(FrameAddrInt, LowestStack);
- auto ThenTerm = SplitBlockAndInsertIfThen(
- IsStackLower, &*IP, false,
- MDBuilder(IRB.getContext()).createUnlikelyBranchWeights());
- IRBuilder<> ThenIRB(ThenTerm);
- auto Store = ThenIRB.CreateStore(FrameAddrInt, SanCovLowestStack);
- LowestStack->setNoSanitizeMetadata();
- Store->setNoSanitizeMetadata();
+
+ // Find an insertion point after last "alloca".
+ llvm::Instruction *InsertBefore = NULL;
+ for (auto &I : BB) {
+ if (llvm::isa<llvm::AllocaInst>(I))
+ InsertBefore = I.getNextNode(); // Move past the "alloca".
+ }
+ // But only use it if we actually found an "alloca".
+ if (InsertBefore)
+ IRB.SetInsertPoint(InsertBefore);
+
+ if (Options.StackDepthCallbackMin) {
+ // In callback mode, only add call when stack depth reaches minimum.
+ const DataLayout &DL = M->getDataLayout();
+ uint32_t EstimatedStackSize = 0;
+
+ // Make an estimate on the stack usage.
+ for (auto &I : BB) {
+ if (auto *AI = dyn_cast<AllocaInst>(&I)) {
+ if (AI->isStaticAlloca()) {
+ uint32_t Bytes = DL.getTypeAllocSize(AI->getAllocatedType());
+ if (AI->isArrayAllocation()) {
+ if (const ConstantInt *arraySize =
+ dyn_cast<ConstantInt>(AI->getArraySize()))
+ Bytes *= arraySize->getZExtValue();
+ }
+ EstimatedStackSize += Bytes;
----------------
kees wrote:
I've added a more detailed comment to the accounting loop (and moved the
insertion calculation there since it's only needed for the callback case). And
I've tweaked the documentation a bit more with a short example.
https://github.com/llvm/llvm-project/pull/138323
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