No -fsanitize=function warning when calling noexcept function through non-noexcept...

As discussed in the mail thread <https://groups.google.com/a/isocpp.org/forum/
#!topic/std-discussion/T64_dW3WKUk> "Calling noexcept function throug non-
noexcept pointer is undefined behavior?", such a call should not be UB.
However, Clang currently warns about it.

There is no cheap check whether two function type_infos only differ in noexcept,
so pass those two type_infos as additional data to the function_type_mismatch
handler (with the optimization of passing a null "static callee type" info when
that is already noexcept, so the additional check can be avoided anyway).  For
the Itanium ABI (which appears to be the only one that happens to be used on
platforms that support -fsanitize=function, and which appears to only record
noexcept information for pointer-to-function type_infos, not for function
type_infos themselves), we then need to check the mangled names for occurrence
of "Do" representing "noexcept".

This is the cfe part of a patch covering both cfe and compiler-rt.

Differential Revision: https://reviews.llvm.org/D40720

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@320978 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index 98740e8f9aabe5e9b0e2d1c52e82cf8161f84ac7..881e5334b461c56d8f95c3576ffcbb610988f4c5 100644 (file)
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -4504,10 +4504,14 @@ RValue CodeGenFunction::EmitCall(QualType CalleeType, const CGCallee &OrigCallee
           Builder.CreateICmpEQ(CalleeRTTI, FTRTTIConst);
       llvm::Constant *StaticData[] = {
         EmitCheckSourceLocation(E->getLocStart()),
-        EmitCheckTypeDescriptor(CalleeType)
+        EmitCheckTypeDescriptor(CalleeType),
+        cast<FunctionProtoType>(FnType)->isNothrow(getContext())
+          ? llvm::Constant::getNullValue(FTRTTIConst->getType())
+          : FTRTTIConst
       };
       EmitCheck(std::make_pair(CalleeRTTIMatch, SanitizerKind::Function),
-                SanitizerHandler::FunctionTypeMismatch, StaticData, CalleePtr);
+                SanitizerHandler::FunctionTypeMismatch, StaticData,
+                {CalleePtr, CalleeRTTI});
 
       Builder.CreateBr(Cont);
       EmitBlock(Cont);