[PATCH] D42508: AST: support protocol conformances on id/class/interfaces in MS ABI

[Saleem Abdulrasool via Phabricator via cfe-commits]

compnerd created this revision.
compnerd added reviewers: rjmccall, rnk.
Herald added a subscriber: cfe-commits.

Add support for mangling ObjC protocol conformances in MS ABI as if they are COM interfaces.  By diverging from the itanium mangling of `objc_protocol` prefixed names, this approach allows for a semi-reasonable, albeit of questionable sanity, undecoration via existing tooling.  There is also the possibility of adding an extension and taking part of the namespace to add the conformance via the `L` and `Z` "modifiers", but the existing tooling would not be able to properly undecorated the symbol even though incidentally `undname` currently produces something legible while wine's implementation is not able to cope with the extension.

This allows for the disambiguation of overloads where the parameter differs only in the protocol conformance of the ObjC type, e.g.

  @protocol P;
  void f(std::vector<id>);
  void f(std::vector<id<P>>);

which clang would previously fail due to the mangling being identical as the protocol conformance was ignored.


Repository:
  rC Clang

https://reviews.llvm.org/D42508

Files:
  lib/AST/MicrosoftMangle.cpp
  test/CodeGenObjCXX/msabi-protocol-conformance.mm


Index: test/CodeGenObjCXX/msabi-protocol-conformance.mm
===================================================================
--- /dev/null
+++ test/CodeGenObjCXX/msabi-protocol-conformance.mm
@@ -0,0 +1,25 @@
+// RUN: %clang_cc1 -triple thumbv7-windows-msvc -fobjc-runtime=ios-6.0 -o - -emit-llvm %s | FileCheck %s
+
+ at protocol P;
+ at protocol Q;
+
+ at class I;
+
+void f(id<P>) {}
+// CHECK-LABEL: "\01?f@@YAXPAU?$objc_object at YP@@@@@Z"
+
+void f(id<P, Q>) {}
+// CHECK-LABEL: "\01?f@@YAXPAU?$objc_object at YP@@YQ@@@@@Z"
+
+void f(Class<P>) {}
+// CHECK-LABEL: "\01?f@@YAXPAU?$objc_class at YP@@@@@Z"
+
+void f(Class<P, Q>) {}
+// CHECK-LABEL: "\01?f@@YAXPAU?$objc_class at YP@@YQ@@@@@Z"
+
+void f(I<P> *) {}
+// CHECK-LABEL: "\01?f@@YAXPAU?$I at YP@@@@@Z"
+
+void f(I<P, Q> *) {}
+// CHECK-LABEL: "\01?f@@YAXPAU?$I at YP@@YQ@@@@@Z"
+
Index: lib/AST/MicrosoftMangle.cpp
===================================================================
--- lib/AST/MicrosoftMangle.cpp
+++ lib/AST/MicrosoftMangle.cpp
@@ -2451,9 +2451,27 @@

 void MicrosoftCXXNameMangler::mangleType(const ObjCObjectType *T, Qualifiers,
                                          SourceRange Range) {
-  // We don't allow overloading by different protocol qualification,
-  // so mangling them isn't necessary.
-  mangleType(T->getBaseType(), Range, QMM_Drop);
+  if (T->qual_empty())
+    return mangleType(T->getBaseType(), Range, QMM_Drop);
+
+  mangleTagTypeKind(TTK_Struct);
+
+  Out << "?$";
+  if (T->isObjCId())
+    mangleSourceName("objc_object");
+  else if (T->isObjCClass())
+    mangleSourceName("objc_class");
+  else
+    mangleSourceName(T->getInterface()->getName());
+
+  for (const auto &Q : T->quals()) {
+    Out << 'Y';
+    mangleSourceName(Q->getName());
+    Out << '@';
+  }
+  Out << '@';
+
+  Out << '@';
 }

 void MicrosoftCXXNameMangler::mangleType(const BlockPointerType *T,


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