diff options
author | Roman Lebedev <lebedev.ri@gmail.com> | 2019-01-15 09:44:13 +0000 |
---|---|---|
committer | Roman Lebedev <lebedev.ri@gmail.com> | 2019-01-15 09:44:13 +0000 |
commit | 79ce8bef6245e0c3fed3d4549fb2fdb8bd966677 (patch) | |
tree | 6a333bb8483fb6ce589dc1565ad3c7f98ebdf40b /llvm | |
parent | 17d4126da0862ec1be94da8bd3d432779b1044a0 (diff) |
[llvm][IRBuilder] Introspection for CreateAlignmentAssumption*() functions
Summary:
Clang calls these functions to produce IR for assume-aligned attributes.
I would like to teach UBSAN to verify these assumptions.
For that, i need to access the final pointer on which the check is performed,
and the actual `icmp` that does the check.
The alternative to this would be to fully re-implement this in clang.
This is a second commit, the original one was r351104,
which was mass-reverted in r351159 because 2 compiler-rt tests were failing.
Reviewers: spatel, dneilson, craig.topper, dblaikie, hfinkel
Reviewed By: hfinkel
Subscribers: hfinkel, llvm-commits
Differential Revision: https://reviews.llvm.org/D54588
Diffstat (limited to 'llvm')
-rw-r--r-- | llvm/include/llvm/IR/IRBuilder.h | 26 |
1 files changed, 19 insertions, 7 deletions
diff --git a/llvm/include/llvm/IR/IRBuilder.h b/llvm/include/llvm/IR/IRBuilder.h index 32c06419c2a..fac2ff46c45 100644 --- a/llvm/include/llvm/IR/IRBuilder.h +++ b/llvm/include/llvm/IR/IRBuilder.h @@ -2234,11 +2234,12 @@ public: private: /// Helper function that creates an assume intrinsic call that /// represents an alignment assumption on the provided Ptr, Mask, Type - /// and Offset. + /// and Offset. It may be sometimes useful to do some other logic + /// based on this alignment check, thus it can be stored into 'TheCheck'. CallInst *CreateAlignmentAssumptionHelper(const DataLayout &DL, Value *PtrValue, Value *Mask, - Type *IntPtrTy, - Value *OffsetValue) { + Type *IntPtrTy, Value *OffsetValue, + Value **TheCheck) { Value *PtrIntValue = CreatePtrToInt(PtrValue, IntPtrTy, "ptrint"); if (OffsetValue) { @@ -2257,6 +2258,9 @@ private: Value *Zero = ConstantInt::get(IntPtrTy, 0); Value *MaskedPtr = CreateAnd(PtrIntValue, Mask, "maskedptr"); Value *InvCond = CreateICmpEQ(MaskedPtr, Zero, "maskcond"); + if (TheCheck) + *TheCheck = InvCond; + return CreateAssumption(InvCond); } @@ -2267,9 +2271,13 @@ public: /// An optional offset can be provided, and if it is provided, the offset /// must be subtracted from the provided pointer to get the pointer with the /// specified alignment. + /// + /// It may be sometimes useful to do some other logic + /// based on this alignment check, thus it can be stored into 'TheCheck'. CallInst *CreateAlignmentAssumption(const DataLayout &DL, Value *PtrValue, unsigned Alignment, - Value *OffsetValue = nullptr) { + Value *OffsetValue = nullptr, + Value **TheCheck = nullptr) { assert(isa<PointerType>(PtrValue->getType()) && "trying to create an alignment assumption on a non-pointer?"); auto *PtrTy = cast<PointerType>(PtrValue->getType()); @@ -2277,7 +2285,7 @@ public: Value *Mask = ConstantInt::get(IntPtrTy, Alignment > 0 ? Alignment - 1 : 0); return CreateAlignmentAssumptionHelper(DL, PtrValue, Mask, IntPtrTy, - OffsetValue); + OffsetValue, TheCheck); } /// Create an assume intrinsic call that represents an alignment @@ -2287,11 +2295,15 @@ public: /// must be subtracted from the provided pointer to get the pointer with the /// specified alignment. /// + /// It may be sometimes useful to do some other logic + /// based on this alignment check, thus it can be stored into 'TheCheck'. + /// /// This overload handles the condition where the Alignment is dependent /// on an existing value rather than a static value. CallInst *CreateAlignmentAssumption(const DataLayout &DL, Value *PtrValue, Value *Alignment, - Value *OffsetValue = nullptr) { + Value *OffsetValue = nullptr, + Value **TheCheck = nullptr) { assert(isa<PointerType>(PtrValue->getType()) && "trying to create an alignment assumption on a non-pointer?"); auto *PtrTy = cast<PointerType>(PtrValue->getType()); @@ -2309,7 +2321,7 @@ public: ConstantInt::get(IntPtrTy, 0), "mask"); return CreateAlignmentAssumptionHelper(DL, PtrValue, Mask, IntPtrTy, - OffsetValue); + OffsetValue, TheCheck); } }; |