[ASTImporter] Fix inequivalence of unresolved exception spec

Summary:
Structural equivalence of methods can falsely report false when the
exception specifier is unresolved (i.e unevaluated or not instantiated).

(This caused one assertion during bitcoin ctu-analysis.)

Reviewers: a_sidorin, shafik, a.sidorin

Subscribers: rnkovacs, dkrupp, Szelethus, gamesh411, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D61424

llvm-svn: 360261

1 files changed, 5 insertions, 0 deletions

diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index da0d68900af..7ce2abee6ce 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -3130,6 +3130,11 @@ ExpectedDecl ASTNodeImporter::VisitFunctionDecl(FunctionDecl *D) {
     auto *Recent = const_cast<FunctionDecl *>(
           FoundByLookup->getMostRecentDecl());
     ToFunction->setPreviousDecl(Recent);
+    // FIXME Probably we should merge exception specifications.  E.g. In the
+    // "To" context the existing function may have exception specification with
+    // noexcept-unevaluated, while the newly imported function may have an
+    // evaluated noexcept.  A call to adjustExceptionSpec() on the imported
+    // decl and its redeclarations may be required.
   }
 
   // Import Ctor initializers.