assigned to @timurrrr

Any suggestions?
It looks like getCanonicalCallConv should know whether it's called for a free function or a CXX method :(

Let's not go down that road.

This needs to be handled in the function-merging logic: it's okay to merge a function with CC_Default with a function with an explicit CC if the default CC for that kind of function is the same as the explicit CC. This is the code at SemaDecl.cpp:1962. If you do this right, you should also get the analogous case with _thiscall on a method (admittedly, it's harder to redeclare those).

Let's not go down that road.

This needs to be handled in the function-merging logic: it's okay to merge a
function with CC_Default with a function with an explicit CC if the default CC
for that kind of function is the same as the explicit CC. This is the code at
SemaDecl.cpp:1962.
OK, I got some code like this working.
Will send it for review when I'm sure what I'm doing :)

But currently it assumes CC_Default == CC_C which is might not be true for free functions on some archs (right?).

If you do this right, you should also get the analogous
case with _thiscall on a method (admittedly, it's harder to redeclare those).
Not that hard :)

class A {
 public:
    void bar();
};

void __thiscall A::bar() {}

Working on this...

Patch sent out for review a few days ago, assigning to myself.

One more thing to fix:

$ cat cdecl_pointer.cpp
typedef void (__cdecl * PTR)();

void foo() {}

void bar(PTR h) {}

int main() {
bar(&foo);
}

$ clang -c cdecl_pointer.cpp && echo "OK"
OK

$ clang -c -Xclang -cxx-abi -Xclang microsoft cdecl_pointer.cpp && echo "OK" || echo "FAIL"
cdecl_pointer.cpp:8:3: error: no matching function for call to 'bar'
bar(&foo);
^~~
cdecl_pointer.cpp:5:6: note: candidate function not viable: no known conversion from 'void ()()' to 'PTR' (aka 'void ()() attribute((cdecl))') for 1st argument
void bar(PTR h) {}
^
1 error generated.
FAIL

comment #​5 repro is not llvm/llvm-bugzilla-archive#13457

s/not/now

Fixed as of r162639.

Good job, Timur.

mentioned in issue llvm/llvm-bugzilla-archive#13457