[ubsan] Save a ptrtoint when emitting alignment checks

The alignment check emits a ptrtoint instruction which can be reused in
the call to the diagnostic handler.

llvm-svn: 314749

1 files changed, 10 insertions, 5 deletions

diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index ba970b9bde1..24de6da2821 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -656,6 +656,7 @@ void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
   }
 
   uint64_t AlignVal = 0;
+  llvm::Value *PtrAsInt = nullptr;
 
   if (SanOpts.has(SanitizerKind::Alignment) &&
       !SkippedChecks.has(SanitizerKind::Alignment)) {
@@ -666,11 +667,11 @@ void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
     // The glvalue must be suitably aligned.
     if (AlignVal > 1 &&
         (!PtrToAlloca || PtrToAlloca->getAlignment() < AlignVal)) {
-      llvm::Value *Align =
-          Builder.CreateAnd(Builder.CreatePtrToInt(Ptr, IntPtrTy),
-                            llvm::ConstantInt::get(IntPtrTy, AlignVal - 1));
+      PtrAsInt = Builder.CreatePtrToInt(Ptr, IntPtrTy);
+      llvm::Value *Align = Builder.CreateAnd(
+          PtrAsInt, llvm::ConstantInt::get(IntPtrTy, AlignVal - 1));
       llvm::Value *Aligned =
-        Builder.CreateICmpEQ(Align, llvm::ConstantInt::get(IntPtrTy, 0));
+          Builder.CreateICmpEQ(Align, llvm::ConstantInt::get(IntPtrTy, 0));
       Checks.push_back(std::make_pair(Aligned, SanitizerKind::Alignment));
     }
   }
@@ -683,7 +684,8 @@ void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
         EmitCheckSourceLocation(Loc), EmitCheckTypeDescriptor(Ty),
         llvm::ConstantInt::get(Int8Ty, AlignVal ? llvm::Log2_64(AlignVal) : 1),
         llvm::ConstantInt::get(Int8Ty, TCK)};
-    EmitCheck(Checks, SanitizerHandler::TypeMismatch, StaticData, Ptr);
+    EmitCheck(Checks, SanitizerHandler::TypeMismatch, StaticData,
+              PtrAsInt ? PtrAsInt : Ptr);
   }
 
   // If possible, check that the vptr indicates that there is a subobject of
@@ -2599,6 +2601,9 @@ llvm::Constant *CodeGenFunction::EmitCheckTypeDescriptor(QualType T) {
 llvm::Value *CodeGenFunction::EmitCheckValue(llvm::Value *V) {
   llvm::Type *TargetTy = IntPtrTy;
 
+  if (V->getType() == TargetTy)
+    return V;
+
   // Floating-point types which fit into intptr_t are bitcast to integers
   // and then passed directly (after zero-extension, if necessary).
   if (V->getType()->isFloatingPointTy()) {