r297316 - Take into account C++17's noexcept function types during merging -- it should

[Richard Smith via cfe-commits]

Author: rsmith
Date: Wed Mar  8 17:00:26 2017
New Revision: 297316

URL: http://llvm.org/viewvc/llvm-project?rev=297316&view=rev
Log:
Take into account C++17's noexcept function types during merging -- it should
be possible to merge a declaration with an unresolved function type against one
with a resolved function type.

Added:
    cfe/trunk/test/Modules/Inputs/cxx17/
    cfe/trunk/test/Modules/Inputs/cxx17/decls.h
    cfe/trunk/test/Modules/Inputs/cxx17/module.modulemap
    cfe/trunk/test/Modules/cxx17.cpp
Modified:
    cfe/trunk/lib/Serialization/ASTReaderDecl.cpp

Modified: cfe/trunk/lib/Serialization/ASTReaderDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Serialization/ASTReaderDecl.cpp?rev=297316&r1=297315&r2=297316&view=diff
==============================================================================
--- cfe/trunk/lib/Serialization/ASTReaderDecl.cpp (original)
+++ cfe/trunk/lib/Serialization/ASTReaderDecl.cpp Wed Mar  8 17:00:26 2017
@@ -2758,9 +2758,23 @@ static bool isSameEntity(NamedDecl *X, N
                         CtorY->getInheritedConstructor().getConstructor()))
         return false;
     }
+    ASTContext &C = FuncX->getASTContext();
+    if (!C.hasSameType(FuncX->getType(), FuncY->getType())) {
+      // We can get functions with different types on the redecl chain in C++17
+      // if they have differing exception specifications and at least one of
+      // the excpetion specs is unresolved.
+      // FIXME: Do we need to check for C++14 deduced return types here too?
+      auto *XFPT = FuncX->getType()->getAs<FunctionProtoType>();
+      auto *YFPT = FuncY->getType()->getAs<FunctionProtoType>();
+      if (C.getLangOpts().CPlusPlus1z && XFPT && YFPT &&
+          (isUnresolvedExceptionSpec(XFPT->getExceptionSpecType()) ||
+           isUnresolvedExceptionSpec(YFPT->getExceptionSpecType())) &&
+          C.hasSameFunctionTypeIgnoringExceptionSpec(FuncX->getType(),
+                                                     FuncY->getType()))
+        return true;
+      return false;
+    }
     return FuncX->getLinkageInternal() == FuncY->getLinkageInternal() &&
-           FuncX->getASTContext().hasSameType(FuncX->getType(),
-                                              FuncY->getType()) &&
            hasSameOverloadableAttrs(FuncX, FuncY);
   }
 

Added: cfe/trunk/test/Modules/Inputs/cxx17/decls.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/cxx17/decls.h?rev=297316&view=auto
==============================================================================
--- cfe/trunk/test/Modules/Inputs/cxx17/decls.h (added)
+++ cfe/trunk/test/Modules/Inputs/cxx17/decls.h Wed Mar  8 17:00:26 2017
@@ -0,0 +1,3 @@
+struct MergeExceptionSpec {
+  ~MergeExceptionSpec(); // unevaluated exception spec
+};

Added: cfe/trunk/test/Modules/Inputs/cxx17/module.modulemap
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/Inputs/cxx17/module.modulemap?rev=297316&view=auto
==============================================================================
--- cfe/trunk/test/Modules/Inputs/cxx17/module.modulemap (added)
+++ cfe/trunk/test/Modules/Inputs/cxx17/module.modulemap Wed Mar  8 17:00:26 2017
@@ -0,0 +1 @@
+module Decls { header "decls.h" }

Added: cfe/trunk/test/Modules/cxx17.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Modules/cxx17.cpp?rev=297316&view=auto
==============================================================================
--- cfe/trunk/test/Modules/cxx17.cpp (added)
+++ cfe/trunk/test/Modules/cxx17.cpp Wed Mar  8 17:00:26 2017
@@ -0,0 +1,11 @@
+// RUN: rm -rf %t
+// RUN: %clang_cc1 -x c++ -std=c++1z -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -I %S/Inputs/cxx17 %s -verify -fno-modules-error-recovery
+
+// expected-no-diagnostics
+struct MergeExceptionSpec {
+  ~MergeExceptionSpec();
+} mergeExceptionSpec; // trigger evaluation of exception spec
+
+#include "decls.h"
+
+MergeExceptionSpec mergeExceptionSpec2;