Rework Microsoft __if_exists/__if_not_exists parsing and semantic

analysis to separate dependent names from non-dependent names. For
dependent names, we'll behave differently from Visual C++:

  - For __if_exists/__if_not_exists at class scope, we'll just warn
    and then ignore them.
  - For __if_exists/__if_not_exists in statements, we'll treat the
    inner statement as a compound statement, which we only instantiate
    in templates where the dependent name (after instantiation)
    exists. This behavior is different from VC++, but it's as close as
    we can get without encroaching ridiculousness.

The latter part (dependent statements) is not yet implemented.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@142864 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 18 insertions, 15 deletions

diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp
index 7583ccafeb..3d3d7c21cb 100644
--- a/lib/Parse/ParseDeclCXX.cpp
+++ b/lib/Parse/ParseDeclCXX.cpp
@@ -2757,25 +2757,32 @@ void Parser::ParseMicrosoftAttributes(ParsedAttributes &attrs,
 
 void Parser::ParseMicrosoftIfExistsClassDeclaration(DeclSpec::TST TagType,
                                                     AccessSpecifier& CurAS) {
-  bool Result;
+  IfExistsCondition Result;
   if (ParseMicrosoftIfExistsCondition(Result))
     return;
   
-  if (Tok.isNot(tok::l_brace)) {
+  BalancedDelimiterTracker Braces(*this, tok::l_brace);
+  if (Braces.consumeOpen()) {
     Diag(Tok, diag::err_expected_lbrace);
     return;
   }
-  ConsumeBrace();
 
-  // Condition is false skip all inside the {}.
-  if (!Result) {
-    SkipUntil(tok::r_brace, false);
+  switch (Result.Behavior) {
+  case IEB_Parse:
+    // Parse the declarations below.
+    break;
+        
+  case IEB_Dependent:
+    Diag(Result.KeywordLoc, diag::warn_microsoft_dependent_exists)
+      << Result.IsIfExists;
+    // Fall through to skip.
+      
+  case IEB_Skip:
+    Braces.skipToEnd();
     return;
   }
 
-  // Condition is true, parse the declaration.
-  while (Tok.isNot(tok::r_brace)) {
-
+  while (Tok.isNot(tok::r_brace) && Tok.isNot(tok::eof)) {
     // __if_exists, __if_not_exists can nest.
     if ((Tok.is(tok::kw___if_exists) || Tok.is(tok::kw___if_not_exists))) {
       ParseMicrosoftIfExistsClassDeclaration((DeclSpec::TST)TagType, CurAS);
@@ -2808,10 +2815,6 @@ void Parser::ParseMicrosoftIfExistsClassDeclaration(DeclSpec::TST TagType,
     // Parse all the comma separated declarators.
     ParseCXXClassMemberDeclaration(CurAS, 0);
   }
-
-  if (Tok.isNot(tok::r_brace)) {
-    Diag(Tok, diag::err_expected_rbrace);
-    return;
-  }
-  ConsumeBrace();
+  
+  Braces.consumeClose();
 }