Author: rnk
Date: Wed May 11 12:43:13 2016
New Revision: 269214
URL: http://llvm.org/viewvc/llvm-project?rev=269214&view=rev
Log:
Relax -Wcalling-convention-cast when casting to the default convention (cdecl)
Modified:
cfe/trunk/lib/Sema/SemaCast.cpp
cfe/trunk/test/Sema/callingconv-cast.c
Modified: cfe/trunk/lib/Sema/SemaCast.cpp
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaCast.cpp?rev=269214&r1=269213&r2=269214&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaCast.cpp (original)
+++ cfe/trunk/lib/Sema/SemaCast.cpp Wed May 11 12:43:13 2016
@@ -1760,7 +1760,15 @@ static void DiagnoseCallingConvCast(Sema
if (!FD || !FD->hasBody(Definition))
return;
- // The source expression is a pointer to a known function defined in this TU.
+ // Only warn if we are casting from the default convention to a non-default
+ // convention. This can happen when the programmer forgot to apply the
calling
+ // convention to the function definition and then inserted this cast to
+ // satisfy the type system.
+ CallingConv DefaultCC = Self.getASTContext().getDefaultCallingConvention(
+ FD->isVariadic(), FD->isCXXInstanceMember());
+ if (DstCC == DefaultCC || SrcCC != DefaultCC)
+ return;
+
// Diagnose this cast, as it is probably bad.
StringRef SrcCCName = FunctionType::getNameForCallConv(SrcCC);
StringRef DstCCName = FunctionType::getNameForCallConv(DstCC);
Modified: cfe/trunk/test/Sema/callingconv-cast.c
URL:
http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/callingconv-cast.c?rev=269214&r1=269213&r2=269214&view=diff
==============================================================================
--- cfe/trunk/test/Sema/callingconv-cast.c (original)
+++ cfe/trunk/test/Sema/callingconv-cast.c Wed May 11 12:43:13 2016
@@ -21,6 +21,10 @@ void mismatched(int x) {}
typedef void (WINAPI *callback_t)(int);
void take_callback(callback_t callback);
+void WINAPI mismatched_stdcall(int x) {}
+
+void take_opaque_fn(void (*callback)(int));
+
int main() {
// expected-warning@+1 {{cast between incompatible calling conventions
'cdecl' and 'stdcall'}}
take_callback((callback_t)mismatched);
@@ -44,6 +48,11 @@ int main() {
// Another way to suppress the warning.
take_callback((callback_t)(void*)mismatched);
+
+ // Don't warn, because we're casting from stdcall to cdecl. Usually that
means
+ // the programmer is rinsing the function pointer through some kind of opaque
+ // API.
+ take_opaque_fn((void (*)(int))mismatched_stdcall);
}
// MSFIXIT: fix-it:"{{.*}}callingconv-cast.c":{19:6-19:6}:"WINAPI "
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