Ultrasimplistic sketch for the parsing of C++ template-ids. This won't
become useful or correct until we (1) parse template arguments
correctly, (2) have some way to turn template-ids into types,
declarators, etc., and (3) have a real representation of templates.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@61208 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/MinimalAction.cpp b/lib/Parse/MinimalAction.cpp
index 5837810..c4e7ecc 100644
--- a/lib/Parse/MinimalAction.cpp
+++ b/lib/Parse/MinimalAction.cpp
@@ -73,6 +73,16 @@
   return false;
 }
 
+  /// isTemplateName - Determines whether the identifier II is a
+  /// template name in the current scope, and returns the template
+  /// declaration if II names a template. An optional CXXScope can be
+  /// passed to indicate the C++ scope in which the identifier will be
+  /// found. 
+Action::DeclTy *MinimalAction::isTemplateName(IdentifierInfo &II, Scope *S,
+                                              const CXXScopeSpec *SS ) {
+  return 0;
+}
+
 /// ActOnDeclarator - If this is a typedef declarator, we modify the
 /// IdentifierInfo::FETokenInfo field to keep track of this fact, until S is
 /// popped.
diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp
index 407aa9c..16e7e77 100644
--- a/lib/Parse/ParseDecl.cpp
+++ b/lib/Parse/ParseDecl.cpp
@@ -1452,13 +1452,27 @@
 
       if (Tok.is(tok::identifier)) {
         assert(Tok.getIdentifierInfo() && "Not an identifier?");
-        // Determine whether this identifier is a C++ constructor name or
-        // a normal identifier.
-        if (Actions.isCurrentClassName(*Tok.getIdentifierInfo(), CurScope)) {
+
+        // If this identifier is followed by a '<', we may have a template-id.
+        DeclTy *Template;
+        if (getLang().CPlusPlus && NextToken().is(tok::less) &&
+            (Template = Actions.isTemplateName(*Tok.getIdentifierInfo(), 
+                                               CurScope))) {
+          IdentifierInfo *II = Tok.getIdentifierInfo();
+          AnnotateTemplateIdToken(Template, 0);
+          // FIXME: Set the declarator to a template-id. How? I don't
+          // know... for now, just use the identifier.
+          D.SetIdentifier(II, Tok.getLocation());
+        }
+        // If this identifier is the name of the current class, it's a
+        // constructor name. 
+        else if (getLang().CPlusPlus &&
+                 Actions.isCurrentClassName(*Tok.getIdentifierInfo(), CurScope))
           D.setConstructor(Actions.isTypeName(*Tok.getIdentifierInfo(),
                                               CurScope),
                            Tok.getLocation());
-        } else
+        // This is a normal identifier.
+        else
           D.SetIdentifier(Tok.getIdentifierInfo(), Tok.getLocation());
         ConsumeToken();
         goto PastIdentifier;
diff --git a/lib/Parse/ParseTemplate.cpp b/lib/Parse/ParseTemplate.cpp
index d21dc4a..5d0c4b5 100644
--- a/lib/Parse/ParseTemplate.cpp
+++ b/lib/Parse/ParseTemplate.cpp
@@ -46,8 +46,19 @@
   // Try to parse the template parameters, and the declaration if
   // successful.
   DeclTy *TemplateDecl = 0;
-  if(ParseTemplateParameters(0))
+  if (Tok.is(tok::less) && NextToken().is(tok::greater)) {
+    // This is a template specialization. Just consume the angle
+    // brackets and parse the declaration or function definition that
+    // follows.
+    // FIXME: Record somehow that we're in an explicit specialization.
+    ConsumeToken();
+    ConsumeToken();
+    TemplateParmScope.Exit();
     TemplateDecl = ParseDeclarationOrFunctionDefinition();
+  } else {
+    if(ParseTemplateParameters(0))
+      TemplateDecl = ParseDeclarationOrFunctionDefinition();
+  }
 
   return TemplateDecl;
 }
@@ -243,7 +254,7 @@
 
 /// ParseNonTypeTemplateParameter - Handle the parsing of non-type
 /// template parameters (e.g., in "template<int Size> class array;"). 
-
+///
 ///       template-parameter:
 ///         ...
 ///         parameter-declaration
@@ -289,3 +300,96 @@
   
   return Param;
 }
+
+/// AnnotateTemplateIdToken - The current token is an identifier that
+/// refers to the template declaration Template, and is followed by a
+/// '<'. Turn this template-id into a template-id annotation token.
+void Parser::AnnotateTemplateIdToken(DeclTy *Template, const CXXScopeSpec *SS) {
+  assert(getLang().CPlusPlus && "Can only annotate template-ids in C++");
+  assert(Template && Tok.is(tok::identifier) && NextToken().is(tok::less) &&
+         "Parser isn't at the beginning of a template-id");
+
+  // Consume the template-name.
+  SourceLocation TemplateNameLoc = ConsumeToken();
+
+  // Consume the '<'.
+  SourceLocation LAngleLoc = ConsumeToken();
+
+  // Parse the optional template-argument-list.
+  TemplateArgList TemplateArgs;
+  if (Tok.isNot(tok::greater) && ParseTemplateArgumentList(TemplateArgs)) {
+    // Try to find the closing '>'.
+    SkipUntil(tok::greater, true, true);
+
+    // FIXME: What's our recovery strategy for failed template-argument-lists?
+    return;
+  }
+
+  if (Tok.isNot(tok::greater))
+    return;
+
+  // Determine the location of the '>'. We won't actually consume this
+  // token, because we'll be replacing it with the template-id.
+  SourceLocation RAngleLoc = Tok.getLocation();
+  
+  Tok.setKind(tok::annot_template_id);
+  Tok.setAnnotationEndLoc(RAngleLoc);
+  Tok.setLocation(TemplateNameLoc);
+  if (SS && SS->isNotEmpty())
+    Tok.setLocation(SS->getBeginLoc());
+
+  TemplateIdAnnotation *TemplateId 
+    = (TemplateIdAnnotation *)malloc(sizeof(TemplateIdAnnotation) + 
+                                  sizeof(TemplateArgTy*) * TemplateArgs.size());
+  TemplateId->TemplateNameLoc = TemplateNameLoc;
+  TemplateId->Template = Template;
+  TemplateId->LAngleLoc = LAngleLoc;
+  TemplateId->NumArgs = TemplateArgs.size();
+  TemplateArgTy **Args = (TemplateArgTy**)(TemplateId + 1);
+  for (unsigned Arg = 0, ArgEnd = TemplateArgs.size(); Arg != ArgEnd; ++Arg)
+    Args[Arg] = TemplateArgs[Arg];
+  Tok.setAnnotationValue(TemplateId);
+
+  // In case the tokens were cached, have Preprocessor replace them with the
+  // annotation token.
+  PP.AnnotateCachedTokens(Tok);
+}
+
+/// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]).
+///
+///       template-argument: [C++ 14.2]
+///         assignment-expression
+///         type-id
+///         id-expression
+Parser::OwningTemplateArgResult Parser::ParseTemplateArgument() {
+  // FIXME: Implement this!
+  return TemplateArgError();
+}
+
+/// ParseTemplateArgumentList - Parse a C++ template-argument-list
+/// (C++ [temp.names]). Returns true if there was an error.
+///
+///       template-argument-list: [C++ 14.2]
+///         template-argument
+///         template-argument-list ',' template-argument
+bool Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs) {
+  while (true) {
+    OwningTemplateArgResult Arg = ParseTemplateArgument();
+    if (Arg.isInvalid()) {
+      SkipUntil(tok::comma, tok::greater, true, true);
+      return true;
+    }
+    else
+      TemplateArgs.push_back(Arg.release());
+    
+    // If the next token is a comma, consume it and keep reading
+    // arguments.
+    if (Tok.isNot(tok::comma)) break;
+
+    // Consume the comma.
+    ConsumeToken();
+  }
+
+  return Tok.isNot(tok::greater);
+}
+
diff --git a/lib/Parse/Parser.cpp b/lib/Parse/Parser.cpp
index 058182e..48b0d5f 100644
--- a/lib/Parse/Parser.cpp
+++ b/lib/Parse/Parser.cpp
@@ -722,6 +722,7 @@
 /// specifier, and another one to get the actual type inside
 /// ParseDeclarationSpecifiers).
 void Parser::TryAnnotateTypeOrScopeToken() {
+  // FIXME: what about template-ids?
   if (Tok.is(tok::annot_qualtypename) || Tok.is(tok::annot_cxxscope))
     return;
 
@@ -730,23 +731,39 @@
     MaybeParseCXXScopeSpecifier(SS);
 
   if (Tok.is(tok::identifier)) {
-    TypeTy *Ty = Actions.isTypeName(*Tok.getIdentifierInfo(), CurScope, &SS);
-    if (Ty) {
-      // This is a typename. Replace the current token in-place with an
-      // annotation type token.
-      Tok.setKind(tok::annot_qualtypename);
-      Tok.setAnnotationValue(Ty);
-      Tok.setAnnotationEndLoc(Tok.getLocation());
-      if (SS.isNotEmpty()) // it was a C++ qualified type name.
-        Tok.setLocation(SS.getBeginLoc());
-
-      // In case the tokens were cached, have Preprocessor replace them with the
-      // annotation token.
-      PP.AnnotateCachedTokens(Tok);
-      return;
+    DeclTy *Template = 0;
+    // If this is a template-id, annotate the template-id token.
+    if (getLang().CPlusPlus && NextToken().is(tok::less) &&
+        (Template = Actions.isTemplateName(*Tok.getIdentifierInfo(), CurScope, 
+                                           &SS)))
+      AnnotateTemplateIdToken(Template, &SS);
+    else {
+      // Determine whether the identifier is a type name.
+      TypeTy *Ty = Actions.isTypeName(*Tok.getIdentifierInfo(), CurScope, &SS);
+      if (Ty) {
+        // This is a typename. Replace the current token in-place with an
+        // annotation type token.
+        Tok.setKind(tok::annot_qualtypename);
+        Tok.setAnnotationValue(Ty);
+        Tok.setAnnotationEndLoc(Tok.getLocation());
+        if (SS.isNotEmpty()) // it was a C++ qualified type name.
+          Tok.setLocation(SS.getBeginLoc());
+        
+        // In case the tokens were cached, have Preprocessor replace
+        // them with the annotation token.
+        PP.AnnotateCachedTokens(Tok);
+        return;
+      }
     }
+
+    // We either have an identifier that is not a type name or we have
+    // just created a template-id that might be a type name. Both
+    // cases will be handled below.
   }
 
+  // FIXME: check for a template-id token here, and look it up if it
+  // names a type.
+
   if (SS.isNotEmpty()) {
     // A C++ scope specifier that isn't followed by a typename.
     // Push the current token back into the token stream (or revert it if it is