r213594 - Avoid crash if default argument parsed with errors.

[Serge Pavlov]

Author: sepavloff
Date: Mon Jul 21 20:54:49 2014
New Revision: 213594

URL: http://llvm.org/viewvc/llvm-project?rev=213594&view=rev
Log:
Avoid crash if default argument parsed with errors.

If function parameters have default values, and that of the second
parameter is parsed with errors, function declaration would have
a parameter without default value that follows a parameter with
that. Such declaration breaks logic of selecting overloaded
function. As a solution, put opaque object as default value in such case.

This patch fixes PR20055.

Differential Revision: http://reviews.llvm.org/D4378

Modified:
    cfe/trunk/include/clang/Sema/Sema.h
    cfe/trunk/lib/Parse/ParseCXXInlineMethods.cpp
    cfe/trunk/lib/Parse/ParseDecl.cpp
    cfe/trunk/lib/Sema/SemaDeclCXX.cpp
    cfe/trunk/test/SemaCXX/default1.cpp

Modified: cfe/trunk/include/clang/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=213594&r1=213593&r2=213594&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Sema.h (original)
+++ cfe/trunk/include/clang/Sema/Sema.h Mon Jul 21 20:54:49 2014
@@ -1625,7 +1625,7 @@ public:
   void ActOnParamUnparsedDefaultArgument(Decl *param,
                                          SourceLocation EqualLoc,
                                          SourceLocation ArgLoc);
-  void ActOnParamDefaultArgumentError(Decl *param);
+  void ActOnParamDefaultArgumentError(Decl *param, SourceLocation EqualLoc);
   bool SetParamDefaultArgument(ParmVarDecl *Param, Expr *DefaultArg,
                                SourceLocation EqualLoc);
 

Modified: cfe/trunk/lib/Parse/ParseCXXInlineMethods.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseCXXInlineMethods.cpp?rev=213594&r1=213593&r2=213594&view=diff
==============================================================================
--- cfe/trunk/lib/Parse/ParseCXXInlineMethods.cpp (original)
+++ cfe/trunk/lib/Parse/ParseCXXInlineMethods.cpp Mon Jul 21 20:54:49 2014
@@ -337,7 +337,8 @@ void Parser::ParseLexedMethodDeclaration
       } else
         DefArgResult = ParseAssignmentExpression();
       if (DefArgResult.isInvalid())
-        Actions.ActOnParamDefaultArgumentError(LM.DefaultArgs[I].Param);
+        Actions.ActOnParamDefaultArgumentError(LM.DefaultArgs[I].Param,
+                                               EqualLoc);
       else {
         if (!TryConsumeToken(tok::cxx_defaultarg_end)) {
           // The last two tokens are the terminator and the saved value of

Modified: cfe/trunk/lib/Parse/ParseDecl.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseDecl.cpp?rev=213594&r1=213593&r2=213594&view=diff
==============================================================================
--- cfe/trunk/lib/Parse/ParseDecl.cpp (original)
+++ cfe/trunk/lib/Parse/ParseDecl.cpp Mon Jul 21 20:54:49 2014
@@ -5436,7 +5436,7 @@ void Parser::ParseParameterDeclarationCl
           if (!ConsumeAndStoreInitializer(*DefArgToks, CIK_DefaultArgument)) {
             delete DefArgToks;
             DefArgToks = nullptr;
-            Actions.ActOnParamDefaultArgumentError(Param);
+            Actions.ActOnParamDefaultArgumentError(Param, EqualLoc);
           } else {
             // Mark the end of the default argument so that we know when to
             // stop when we parse it later on.
@@ -5465,7 +5465,7 @@ void Parser::ParseParameterDeclarationCl
           } else
             DefArgResult = ParseAssignmentExpression();
           if (DefArgResult.isInvalid()) {
-            Actions.ActOnParamDefaultArgumentError(Param);
+            Actions.ActOnParamDefaultArgumentError(Param, EqualLoc);
             SkipUntil(tok::comma, tok::r_paren, StopAtSemi | StopBeforeMatch);
           } else {
             // Inform the actions module about the default argument

Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=213594&r1=213593&r2=213594&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Mon Jul 21 20:54:49 2014
@@ -344,13 +344,16 @@ void Sema::ActOnParamUnparsedDefaultArgu
 
 /// ActOnParamDefaultArgumentError - Parsing or semantic analysis of
 /// the default argument for the parameter param failed.
-void Sema::ActOnParamDefaultArgumentError(Decl *param) {
+void Sema::ActOnParamDefaultArgumentError(Decl *param,
+                                          SourceLocation EqualLoc) {
   if (!param)
     return;
 
   ParmVarDecl *Param = cast<ParmVarDecl>(param);
   Param->setInvalidDecl();
   UnparsedDefaultArgLocs.erase(Param);
+  Param->setDefaultArg(new(Context)
+                       OpaqueValueExpr(EqualLoc, Param->getType(), VK_RValue));
 }
 
 /// CheckExtraCXXDefaultArguments - Check for any extra default

Modified: cfe/trunk/test/SemaCXX/default1.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/default1.cpp?rev=213594&r1=213593&r2=213594&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/default1.cpp (original)
+++ cfe/trunk/test/SemaCXX/default1.cpp Mon Jul 21 20:54:49 2014
@@ -62,3 +62,6 @@ int i2() {
     j(2, 3); // expected-error{{too many arguments to function call, expected at most single argument 'f', have 2}}
   }
 }
+
+int pr20055_f(int x = 0, int y = UNDEFINED); // expected-error{{use of undeclared identifier}}
+int pr20055_v = pr20055_f(0);