AST: support ObjC lifetime qualifiers in MS ABI

[compnerd]

Summary

Adjust the ObjC protocol conformance workaround to be more extensible.
Use a synthetic type for the protocol (struct Protocol). Embed this
within a reserved namespace to permit extending the extended pointer
type qualifiers similarly for ObjC lifetime qualifiers.

Introduce additional special handling for __autoreleasing, __strong,
and __weak Objective C lifetime qualifiers. We decorate these by
creating an artificial template type Autoreleasing, Strong, or
Weak in the __ObjC namespace. These are only considered in the
template type specialization and not the function parameter.

[smeenai]

pin_ptr is technically not supposed to appear as a function parameter, and having it in that position can screw up demangling. Considering __strong is the default, it's probably not a good idea to map that one to pin_ptr; whichever qualifier is least likely to appear as a function parameter (though I don't know which one that is) should map to pin_ptr. The other lifetimes seem to demangle fine wherever you place them.

Do you want to add some tests for the mangling of qualifiers on function parameters themselves? That would also demonstrate the potential demangling issue.

[rjmccall]

It's not just that functions can't be overloaded on the parameter-variable type qualifier — it's not part of the function type at all, just like making a parameter 'const int' instead of 'int' is not part of the function type. I understand that MSVC mangles some things that really shouldn't be mangled, but I would greatly prefer if you could make an exception for this.

Separately, re-using existing manglings like this seems *really* sketchy. Is this 100% necessary? There's no way to just fake something up?

[compnerd]

Hmm, the only thing that we could fake would be namespaces on the parameter types. Is that better? I'm not tied to re-using the existing mangling.

[rjmccall]

In D42614#990808, @compnerd wrote:

Hmm, the only thing that we could fake would be namespaces on the parameter types. Is that better? I'm not tied to re-using the existing mangling.

I'm just worried about re-using the existing mangling causing a problem in the long run. If you're certain that it would never be sensical to talk about e.g. a cli::pin_ptr<__strong id>, then ok.

[compnerd]

Yeah, Im afraid I cannot definitely say that will never be sensible. I think I would, in fact, prefer an alternative. I'm just not sure what is a good viable alternative, especially since we are constrained in what the grammar accepts. The desugaring of the id and Class types is the saving grace here that grants us some ability to tweak the mangling.

[compnerd]

Address comments from @rjmccall

[compnerd]

@rjmccall, I've updated the approach and no longer abuse the existing decoration styles. This uses a custom namespace with artificial types to differentiate the types. I've also ensured that the parameter types do not encode the type information.

[rjmccall]

In D42614#1001279, @compnerd wrote:

@rjmccall, I've updated the approach and no longer abuse the existing decoration styles. This uses a custom namespace with artificial types to differentiate the types. I've also ensured that the parameter types do not encode the type information.

Alright, thanks, LGTM.

[compnerd]

SVN r324701

lib/AST/MicrosoftMangle.cpp

                           const TemplateArgumentList &TemplateArgs);
   void mangleTemplateArg(const TemplateDecl *TD, const TemplateArgument &TA,
                          const NamedDecl *Parm);
+
+  void mangleObjCProtocol(const ObjCProtocolDecl *PD);
+  void mangleObjCLifetime(const QualType T, Qualifiers Quals,
+                          SourceRange Range);
 };
 }
 

   }
 }
 
+void MicrosoftCXXNameMangler::mangleObjCProtocol(const ObjCProtocolDecl *PD) {
+  llvm::SmallString<64> TemplateMangling;
+  llvm::raw_svector_ostream Stream(TemplateMangling);
+  MicrosoftCXXNameMangler Extra(Context, Stream);
+
+  Stream << "?$";
+  Extra.mangleSourceName("Protocol");
+  Extra.mangleArtificalTagType(TTK_Struct, PD->getName());
+
+  mangleArtificalTagType(TTK_Struct, TemplateMangling, {"__ObjC"});
+}
+
+void MicrosoftCXXNameMangler::mangleObjCLifetime(const QualType Type,
+                                                 Qualifiers Quals,
+                                                 SourceRange Range) {
+  llvm::SmallString<64> TemplateMangling;
+  llvm::raw_svector_ostream Stream(TemplateMangling);
+  MicrosoftCXXNameMangler Extra(Context, Stream);
+
+  Stream << "?$";
+  switch (Quals.getObjCLifetime()) {
+  case Qualifiers::OCL_None:
+  case Qualifiers::OCL_ExplicitNone:
+    break;
+  case Qualifiers::OCL_Autoreleasing:
+    Extra.mangleSourceName("Autoreleasing");
+    break;
+  case Qualifiers::OCL_Strong:
+    Extra.mangleSourceName("Strong");
+    break;
+  case Qualifiers::OCL_Weak:
+    Extra.mangleSourceName("Weak");
+    break;
+  }
+  Extra.manglePointerCVQualifiers(Quals);
+  Extra.manglePointerExtQualifiers(Quals, Type);
+  Extra.mangleType(Type, Range);
+
+  mangleArtificalTagType(TTK_Struct, TemplateMangling, {"__ObjC"});
+}
+
 void MicrosoftCXXNameMangler::mangleQualifiers(Qualifiers Quals,
                                                bool IsMember) {
   // <cvr-qualifiers> ::= [E] [F] [I] <base-cvr-qualifiers>

 
   switch (QMM) {
   case QMM_Drop:
+    if (Quals.hasObjCLifetime())
+      Quals = Quals.withoutObjCLifetime();
     break;
   case QMM_Mangle:
     if (const FunctionType *FT = dyn_cast<FunctionType>(T)) {

   case QMM_Result:
     // Presence of __unaligned qualifier shouldn't affect mangling here.
     Quals.removeUnaligned();
+    if (Quals.hasObjCLifetime())
+      Quals = Quals.withoutObjCLifetime();
     if ((!IsPointer && Quals) || isa<TagType>(T)) {
       Out << '?';
       mangleQualifiers(Quals, false);

 void MicrosoftCXXNameMangler::mangleType(const ObjCObjectPointerType *T,
                                          Qualifiers Quals, SourceRange Range) {
   QualType PointeeType = T->getPointeeType();
+  switch (Quals.getObjCLifetime()) {
+  case Qualifiers::OCL_None:
+  case Qualifiers::OCL_ExplicitNone:
+    break;
+  case Qualifiers::OCL_Autoreleasing:
+  case Qualifiers::OCL_Strong:
+  case Qualifiers::OCL_Weak:
+    return mangleObjCLifetime(PointeeType, Quals, Range);
+  }
   manglePointerCVQualifiers(Quals);
   manglePointerExtQualifiers(Quals, PointeeType);
   mangleType(PointeeType, Range);

   else
     mangleSourceName(T->getInterface()->getName());
 
-  for (const auto &Q : T->quals()) {
-    Out << 'Y'; // cointerface
-    mangleSourceName(Q->getName());
-    Out << '@';
-  }
+  for (const auto &Q : T->quals())
+    mangleObjCProtocol(Q);
   Out << '@';
 
   Out << '@';

test/CodeGenObjCXX/msabi-objc-extensions.mm

+// RUN: %clang_cc1 -triple thumbv7-windows-msvc -fobjc-runtime=ios-6.0 -fobjc-arc -o - -emit-llvm %s | FileCheck %s
+
+@protocol P;
+@protocol Q;
+
+@class I;
+
+void f(id<P>, id, id<P>, id) {}
+// CHECK-LABEL: "\01?f@@YAXPAU?$objc_object@U?$Protocol@UP@@@__ObjC@@@@PAUobjc_object@@01@Z"
+
+void f(id, id<P>, id<P>, id) {}
+// CHECK-LABEL: "\01?f@@YAXPAUobjc_object@@PAU?$objc_object@U?$Protocol@UP@@@__ObjC@@@@10@Z"
+
+void f(id<P>, id<P>) {}
+// CHECK-LABEL: "\01?f@@YAXPAU?$objc_object@U?$Protocol@UP@@@__ObjC@@@@0@Z"
+
+void f(id<P>) {}
+// CHECK-LABEL: "\01?f@@YAXPAU?$objc_object@U?$Protocol@UP@@@__ObjC@@@@@Z"
+
+void f(id<P, Q>) {}
+// CHECK-LABEL: "\01?f@@YAXPAU?$objc_object@U?$Protocol@UP@@@__ObjC@@U?$Protocol@UQ@@@2@@@@Z"
+
+void f(Class<P>) {}
+// CHECK-LABEL: "\01?f@@YAXPAU?$objc_class@U?$Protocol@UP@@@__ObjC@@@@@Z"
+
+void f(Class<P, Q>) {}
+// CHECK-LABEL: "\01?f@@YAXPAU?$objc_class@U?$Protocol@UP@@@__ObjC@@U?$Protocol@UQ@@@2@@@@Z"
+
+void f(I<P> *) {}
+// CHECK-LABEL: "\01?f@@YAXPAU?$I@U?$Protocol@UP@@@__ObjC@@@@@Z"
+
+void f(I<P, Q> *) {}
+// CHECK-LABEL: "\01?f@@YAXPAU?$I@U?$Protocol@UP@@@__ObjC@@U?$Protocol@UQ@@@2@@@@Z"
+
+template <typename>
+struct S {};
+
+void f(S<__unsafe_unretained id>) {}
+// CHECK-LABEL: "\01?f@@YAXU?$S@PAUobjc_object@@@@@Z"
+
+void f(S<__autoreleasing id>) {}
+// CHECK-LABEL: "\01?f@@YAXU?$S@U?$Autoreleasing@PAUobjc_object@@@__ObjC@@@@@Z"
+
+void f(S<__strong id>) {}
+// CHECK-LABEL: "\01?f@@YAXU?$S@U?$Strong@PAUobjc_object@@@__ObjC@@@@@Z"
+
+void f(S<__weak id>) {}
+// CHECK-LABEL: "\01?f@@YAXU?$S@U?$Weak@PAUobjc_object@@@__ObjC@@@@@Z"
+
+void w(__weak id) {}
+// CHECK-LABEL: "\01?w@@YAXPAUobjc_object@@@Z"
+
+void s(__strong id) {}
+// CHECK-LABEL: "\01?s@@YAXPAUobjc_object@@@Z"
+
+void a(__autoreleasing id) {}
+// CHECK-LABEL: "\01?a@@YAXPAUobjc_object@@@Z"
+
+void u(__unsafe_unretained id) {}
+// CHECK-LABEL: "\01?u@@YAXPAUobjc_object@@@Z"
+
+S<__autoreleasing id> g() { return S<__autoreleasing id>(); }
+// CHECK-LABEL: "\01?g@@YA?AU?$S@U?$Autoreleasing@PAUobjc_object@@@__ObjC@@@@XZ"
+
+__autoreleasing id h() { return nullptr; }
+// CHECK-LABEL: "\01?h@@YAPAUobjc_object@@XZ"

test/CodeGenObjCXX/msabi-protocol-conformance.mm

-// RUN: %clang_cc1 -triple thumbv7-windows-msvc -fobjc-runtime=ios-6.0 -o - -emit-llvm %s | FileCheck %s
-
-@protocol P;
-@protocol Q;
-
-@class I;
-
-void f(id<P>, id, id<P>, id) {}
-// CHECK-LABEL: "\01?f@@YAXPAU?$objc_object@YP@@@@PAUobjc_object@@01@Z"
-
-void f(id, id<P>, id<P>, id) {}
-// CHECK-LABEL: "\01?f@@YAXPAUobjc_object@@PAU?$objc_object@YP@@@@10@Z"
-
-void f(id<P>, id<P>) {}
-// CHECK-LABEL: "\01?f@@YAXPAU?$objc_object@YP@@@@0@Z"
-
-void f(id<P>) {}
-// CHECK-LABEL: "\01?f@@YAXPAU?$objc_object@YP@@@@@Z"
-
-void f(id<P, Q>) {}
-// CHECK-LABEL: "\01?f@@YAXPAU?$objc_object@YP@@YQ@@@@@Z"
-
-void f(Class<P>) {}
-// CHECK-LABEL: "\01?f@@YAXPAU?$objc_class@YP@@@@@Z"
-
-void f(Class<P, Q>) {}
-// CHECK-LABEL: "\01?f@@YAXPAU?$objc_class@YP@@YQ@@@@@Z"
-
-void f(I<P> *) {}
-// CHECK-LABEL: "\01?f@@YAXPAU?$I@YP@@@@@Z"
-
-void f(I<P, Q> *) {}
-// CHECK-LABEL: "\01?f@@YAXPAU?$I@YP@@YQ@@@@@Z"
-