Add a 'dynamic' parameter to the objectsize intrinsic

This is meant to be used with clang's __builtin_dynamic_object_size.
When 'true' is passed to this parameter, the intrinsic has the
potential to be folded into instructions that will be evaluated
at run time. When 'false', the objectsize intrinsic behaviour is
unchanged.

rdar://32212419

Differential revision: https://reviews.llvm.org/D56761

llvm-svn: 352664

2 files changed, 4 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
index ce109bc0d4e..f1014b61831 100644
--- a/clang/lib/CodeGen/CGBuiltin.cpp
+++ b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -549,7 +549,8 @@ CodeGenFunction::emitBuiltinObjectSize(const Expr *E, unsigned Type,
   Value *Min = Builder.getInt1((Type & 2) != 0);
   // For GCC compatibility, __builtin_object_size treat NULL as unknown size.
   Value *NullIsUnknown = Builder.getTrue();
-  return Builder.CreateCall(F, {Ptr, Min, NullIsUnknown});
+  Value *Dynamic = Builder.getFalse();
+  return Builder.CreateCall(F, {Ptr, Min, NullIsUnknown, Dynamic});
 }
 
 namespace {
diff --git a/clang/lib/CodeGen/CGExpr.cpp b/clang/lib/CodeGen/CGExpr.cpp
index be30e8215ad..4bd454411a2 100644
--- a/clang/lib/CodeGen/CGExpr.cpp
+++ b/clang/lib/CodeGen/CGExpr.cpp
@@ -727,9 +727,10 @@ void CodeGenFunction::EmitTypeCheck(TypeCheckKind TCK, SourceLocation Loc,
       llvm::Value *F = CGM.getIntrinsic(llvm::Intrinsic::objectsize, Tys);
       llvm::Value *Min = Builder.getFalse();
       llvm::Value *NullIsUnknown = Builder.getFalse();
+      llvm::Value *Dynamic = Builder.getFalse();
       llvm::Value *CastAddr = Builder.CreateBitCast(Ptr, Int8PtrTy);
       llvm::Value *LargeEnough = Builder.CreateICmpUGE(
-          Builder.CreateCall(F, {CastAddr, Min, NullIsUnknown}), Size);
+          Builder.CreateCall(F, {CastAddr, Min, NullIsUnknown, Dynamic}), Size);
       Checks.push_back(std::make_pair(LargeEnough, SanitizerKind::ObjectSize));
     }
   }