[MS Compat] Adjust thiscall to cdecl when deducing template arguments

Function types can be extracted from member pointer types.
However, the type is not appropriate without first adjusting the calling
convention.

This fixes PR25661.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@254323 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Sema/SemaTemplateDeduction.cpp b/lib/Sema/SemaTemplateDeduction.cpp
index 2605acddfacc755af671cf7f51c7527445a18f26..4b811c7e25263ef55ace2d10f69751db00a2e266 100644 (file)
--- a/lib/Sema/SemaTemplateDeduction.cpp
+++ b/lib/Sema/SemaTemplateDeduction.cpp
@@ -1517,10 +1517,19 @@ DeduceTemplateArgumentsByTypeMatch(Sema &S,
       if (!MemPtrArg)
         return Sema::TDK_NonDeducedMismatch;
 
+      QualType ParamPointeeType = MemPtrParam->getPointeeType();
+      if (ParamPointeeType->isFunctionType())
+        S.adjustMemberFunctionCC(ParamPointeeType, /*IsStatic=*/true,
+                                 /*IsCtorOrDtor=*/false, Info.getLocation());
+      QualType ArgPointeeType = MemPtrArg->getPointeeType();
+      if (ArgPointeeType->isFunctionType())
+        S.adjustMemberFunctionCC(ArgPointeeType, /*IsStatic=*/true,
+                                 /*IsCtorOrDtor=*/false, Info.getLocation());
+
       if (Sema::TemplateDeductionResult Result
             = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
-                                                 MemPtrParam->getPointeeType(),
-                                                 MemPtrArg->getPointeeType(),
+                                                 ParamPointeeType,
+                                                 ArgPointeeType,
                                                  Info, Deduced,
                                                  TDF & TDF_IgnoreQualifiers))
         return Result;

diff --git a/test/SemaCXX/calling-conv-compat.cpp b/test/SemaCXX/calling-conv-compat.cpp
index cebac9fad6cdd613d16236f8fd8b631ac94f89d3..20d93b41e1d23b8edfab9e71185b54379a2ab518 100644 (file)
--- a/test/SemaCXX/calling-conv-compat.cpp
+++ b/test/SemaCXX/calling-conv-compat.cpp
@@ -370,6 +370,19 @@ X<fun_cdecl   >::p tmpl6 = &A::method_thiscall;
 X<fun_stdcall >::p tmpl7 = &A::method_stdcall;
 X<fun_fastcall>::p tmpl8 = &A::method_fastcall;
 
+// Make sure we adjust thiscall to cdecl when extracting the function type from
+// a member pointer.
+template <typename> struct Y;
+
+template <typename Fn, typename C>
+struct Y<Fn C::*> {
+  typedef Fn *p;
+};
+
+void __cdecl f_cdecl();
+Y<decltype(&A::method_thiscall)>::p tmpl9 = &f_cdecl;
+
+
 } // end namespace MemberPointers
 
 // Test that lambdas that capture nothing convert to cdecl function pointers.