PR21565: Further refine the conditions for enabling eager parsing of

std::X::swap exception specifications (allowing parsing of non-conforming code
in libstdc++). The old conditions also matched the functions in MSVC's STL,
which were relying on deferred parsing here.

llvm-svn: 222471

2 files changed, 24 insertions, 9 deletions

diff --git a/clang/lib/Parse/ParseCXXInlineMethods.cpp b/clang/lib/Parse/ParseCXXInlineMethods.cpp
index 8469fb96911..e1a5b8e9945 100644
--- a/clang/lib/Parse/ParseCXXInlineMethods.cpp
+++ b/clang/lib/Parse/ParseCXXInlineMethods.cpp
@@ -416,13 +416,12 @@ void Parser::ParseLexedMethodDeclaration(LateParsedMethodDeclaration &LM) {
       Diag(Tok.getLocation(), diag::err_except_spec_unparsed);
 
     // Attach the exception-specification to the method.
-    if (EST != EST_None)
-      Actions.actOnDelayedExceptionSpecification(LM.Method, EST,
-                                                 SpecificationRange,
-                                                 DynamicExceptions,
-                                                 DynamicExceptionRanges,
-                                                 NoexceptExpr.isUsable()?
-                                                   NoexceptExpr.get() : nullptr);
+    Actions.actOnDelayedExceptionSpecification(LM.Method, EST,
+                                               SpecificationRange,
+                                               DynamicExceptions,
+                                               DynamicExceptionRanges,
+                                               NoexceptExpr.isUsable()?
+                                                 NoexceptExpr.get() : nullptr);
 
     assert(!PP.getSourceManager().isBeforeInTranslationUnit(origLoc,
                                                             Tok.getLocation()) &&
diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index f84b4dae8d5..518197e17b9 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -5282,8 +5282,24 @@ void Parser::ParseFunctionDeclarator(Declarator &D,
 
       // Parse exception-specification[opt].
       bool Delayed = D.isFirstDeclarationOfMember() &&
-                     D.isFunctionDeclaratorAFunctionDeclaration() &&
-                     !Actions.isLibstdcxxEagerExceptionSpecHack(D);
+                     D.isFunctionDeclaratorAFunctionDeclaration();
+      if (Delayed && Actions.isLibstdcxxEagerExceptionSpecHack(D) &&
+          GetLookAheadToken(0).is(tok::kw_noexcept) &&
+          GetLookAheadToken(1).is(tok::l_paren) &&
+          GetLookAheadToken(2).is(tok::kw_noexcept) &&
+          GetLookAheadToken(3).is(tok::l_paren) &&
+          GetLookAheadToken(4).is(tok::identifier) &&
+          GetLookAheadToken(4).getIdentifierInfo()->isStr("swap")) {
+        // HACK: We've got an exception-specification
+        //   noexcept(noexcept(swap(...)))
+        // or
+        //   noexcept(noexcept(swap(...)) && noexcept(swap(...)))
+        // on a 'swap' member function. This is a libstdc++ bug; the lookup
+        // for 'swap' will only find the function we're currently declaring,
+        // whereas it expects to find a non-member swap through ADL. Turn off
+        // delayed parsing to give it a chance to find what it expects.
+        Delayed = false;
+      }
       ESpecType = tryParseExceptionSpecification(Delayed,
                                                  ESpecRange,
                                                  DynamicExceptions,