rnk added inline comments.
================
Comment at: lib/Sema/SemaType.cpp:2272
@@ -2271,1 +2271,3 @@
// calling convention.
+ bool is_ctor_or_dtor =
+ (Entity.getNameKind() == DeclarationName::CXXConstructorName) ||
----------------
s/is_ctor_or_dtor/IsCtorOrDtor/, it's the local variable convention.
================
Comment at: lib/Sema/SemaType.cpp:5857-5858
@@ -5860,3 +5856,4 @@
- if (hasExplicitCallingConv(T))
- return;
+ // MS compiler transforms __stdcall in ctors/dtors to __thiscall in 32 bit
+ // mode. We should do the same.
+ if ((CurCC == CC_X86StdCall) && IsCtorOrDtor &&
----------------
I think a more accurate statement would be that MSVC ignores explicit calling
convention attributes on structors in all modes. Compile this example with MSVC
for x64:
struct HVA {
double a, b, c, d;
};
struct A {
__vectorcall A(HVA x);
double f;
};
A::A(HVA x) : f(x.a + x.b + x.c + x.d) {}
Note the warning:
warning C4166: illegal calling convention for constructor/destructor
And HVA is passed indirectly instead of in XMM0-3.
You should consider adding a warning like this when we adjust structor
conventions from something other than `__stdcall`. MSVC doesn't appear to warn
on `__stdcall` structors, probably because it is used accidentally in places
like vswriter.h.
================
Comment at: lib/Sema/SemaType.cpp:5860
@@ +5859,3 @@
+ if ((CurCC == CC_X86StdCall) && IsCtorOrDtor &&
+ (Context.getTargetInfo().getTriple().isWindowsMSVCEnvironment() &&
+ Context.getTargetInfo().getTriple().isArch32Bit()))
----------------
A better test for if we should treat structors specially would be:
Context.getTargetInfo().getCXXABI().isMicrosoft()
It's really the MSVC C++ ABI that requires that structors have special
conventions. I think it has to do with exception handling.
================
Comment at: lib/Sema/SemaType.cpp:5868
@@ +5867,3 @@
+ // __thiscall type to __cdecl for static methods.
+ CallingConv FromCC =
+ Context.getDefaultCallingConvention(IsVariadic, IsStatic);
----------------
In hindsight, a better name for this variable would be `DefaultCC`.
================
Comment at: lib/Sema/SemaType.cpp:5871-5875
@@ +5870,7 @@
+ ToCC = Context.getDefaultCallingConvention(IsVariadic, !IsStatic);
+ if (CurCC != FromCC || FromCC == ToCC)
+ return;
+
+ if (hasExplicitCallingConv(T))
+ return;
+ }
----------------
I think it would be better to wrap both ifs here in `if (!IsCtorOrDtor)`. We
should always adjust ctors and dtors.
http://reviews.llvm.org/D12402
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