From 488fdce9821a06732631aececa351ad75a224b19 Mon Sep 17 00:00:00 2001 From: Richard Smith Date: Thu, 20 Dec 2012 04:11:02 +0000 Subject: [PATCH] Don't use isa(this) in the constructor for CallInst's base class. This has undefined behavior, because the classof implementation attempts to access parts of the not-yet-constructed derived class. Found by clang -fsanitize=vptr. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170658 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/VMCore/Value.cpp | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/lib/VMCore/Value.cpp b/lib/VMCore/Value.cpp index b10e093c152..04ae4415138 100644 --- a/lib/VMCore/Value.cpp +++ b/lib/VMCore/Value.cpp @@ -46,10 +46,13 @@ Value::Value(Type *ty, unsigned scid) SubclassOptionalData(0), SubclassData(0), VTy((Type*)checkType(ty)), UseList(0), Name(0) { // FIXME: Why isn't this in the subclass gunk?? - if (isa(this) || isa(this)) + // Note, we cannot call isa before the CallInst has been + // constructed. + if (SubclassID == Instruction::Call || SubclassID == Instruction::Invoke) assert((VTy->isFirstClassType() || VTy->isVoidTy() || VTy->isStructTy()) && "invalid CallInst type!"); - else if (!isa(this) && !isa(this)) + else if (SubclassID != BasicBlockVal && + (SubclassID < ConstantFirstVal || SubclassID > ConstantLastVal)) assert((VTy->isFirstClassType() || VTy->isVoidTy()) && "Cannot create non-first-class values except for constants!"); } -- 2.34.1