PR41111, PR5925, PR13210: Teach tentative parsing to annotate identifiers and

nested names as id-expressions, using the annot_primary_expr annotation, where
possible. This removes some redundant lookups, and also allows us to
typo-correct within tentative parsing, and to carry on disambiguating past an
identifier which we can determine will fail lookup as both a type and as a
non-type, allowing us to disambiguate more declarations (and thus offer
improved error recovery for such cases).

This also introduces to the parser the notion of a tentatively-declared name,
which is an identifier which we *might* have seen a declaration for in a
tentative parse (but only if we end up disambiguating the tokens as a
declaration). This is necessary to correctly disambiguate cases where a
variable is used within its own initializer.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@162159 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 55 insertions, 2 deletions

diff --git a/include/clang/Lex/Preprocessor.h b/include/clang/Lex/Preprocessor.h
index 02e3f1e7e4..ca2c59d9b3 100644
--- a/include/clang/Lex/Preprocessor.h
+++ b/include/clang/Lex/Preprocessor.h
@@ -724,6 +724,14 @@ public:
       CachedTokens[CachedLexPos-1] = Tok;
   }
 
+  /// TypoCorrectToken - Update the current token to represent the provided
+  /// identifier, in order to cache an action performed by typo correction.
+  void TypoCorrectToken(const Token &Tok) {
+    assert(Tok.getIdentifierInfo() && "Expected identifier token");
+    if (CachedLexPos != 0 && isBacktrackEnabled())
+      CachedTokens[CachedLexPos-1] = Tok;
+  }
+
   /// \brief Recompute the current lexer kind based on the CurLexer/CurPTHLexer/
   /// CurTokenLexer pointers.
   void recomputeCurLexerKind();
diff --git a/include/clang/Parse/Parser.h b/include/clang/Parse/Parser.h
index 4ef92f7dbc..5e80ca36a0 100644
--- a/include/clang/Parse/Parser.h
+++ b/include/clang/Parse/Parser.h
@@ -30,6 +30,7 @@ namespace clang {
   class PragmaHandler;
   class Scope;
   class BalancedDelimiterTracker;
+  class CorrectionCandidateCallback;
   class DeclGroupRef;
   class DiagnosticBuilder;
   class Parser;
@@ -204,6 +205,9 @@ class Parser : public CodeCompletionHandler {
   /// top-level declaration is finished.
   SmallVector<TemplateIdAnnotation *, 16> TemplateIds;
 
+  /// \brief Identifiers which have been declared within a tentative parse.
+  SmallVector<IdentifierInfo *, 8> TentativelyDeclaredIdentifiers;
+
   IdentifierInfo *getSEHExceptKeyword();
 
   /// True if we are within an Objective-C container while parsing C-like decls.
@@ -482,7 +486,28 @@ private:
   // find a type name by attempting typo correction.
   bool TryAnnotateTypeOrScopeToken(bool EnteringContext = false,
                                    bool NeedType = false);
+  bool TryAnnotateTypeOrScopeTokenAfterScopeSpec(bool EnteringContext,
+                                                 bool NeedType,
+                                                 CXXScopeSpec &SS,
+                                                 bool IsNewScope);
   bool TryAnnotateCXXScopeToken(bool EnteringContext = false);
+  enum AnnotatedNameKind {
+    /// Annotation has failed and emitted an error.
+    ANK_Error,
+    /// The identifier is a tentatively-declared name.
+    ANK_TentativeDecl,
+    /// The identifier is a template name. FIXME: Add an annotation for that.
+    ANK_TemplateName,
+    /// The identifier can't be resolved.
+    ANK_Unresolved,
+    /// Annotation was successful.
+    ANK_Success
+  };
+  AnnotatedNameKind TryAnnotateName(bool IsAddressOfOperand,
+                                    CorrectionCandidateCallback *CCC = 0);
+
+  /// Push a tok::annot_cxxscope token onto the token stream.
+  void AnnotateScopeToken(CXXScopeSpec &SS, bool IsNewAnnotation);
 
   /// TryAltiVecToken - Check for context-sensitive AltiVec identifier tokens,
   /// replacing them with the non-context-sensitive keywords.  This returns
@@ -529,12 +554,15 @@ private:
   class TentativeParsingAction {
     Parser &P;
     Token PrevTok;
+    size_t PrevTentativelyDeclaredIdentifierCount;
     unsigned short PrevParenCount, PrevBracketCount, PrevBraceCount;
     bool isActive;
 
   public:
     explicit TentativeParsingAction(Parser& p) : P(p) {
       PrevTok = P.Tok;
+      PrevTentativelyDeclaredIdentifierCount =
+          P.TentativelyDeclaredIdentifiers.size();
       PrevParenCount = P.ParenCount;
       PrevBracketCount = P.BracketCount;
       PrevBraceCount = P.BraceCount;
@@ -543,6 +571,8 @@ private:
     }
     void Commit() {
       assert(isActive && "Parsing action was finished!");
+      P.TentativelyDeclaredIdentifiers.resize(
+          PrevTentativelyDeclaredIdentifierCount);
       P.PP.CommitBacktrackedTokens();
       isActive = false;
     }
@@ -550,6 +580,8 @@ private:
       assert(isActive && "Parsing action was finished!");
       P.PP.Backtrack();
       P.Tok = PrevTok;
+      P.TentativelyDeclaredIdentifiers.resize(
+          PrevTentativelyDeclaredIdentifierCount);
       P.ParenCount = PrevParenCount;
       P.BracketCount = PrevBracketCount;
       P.BraceCount = PrevBraceCount;
@@ -1707,6 +1739,11 @@ private:
   isCXXDeclarationSpecifier(TPResult BracedCastResult = TPResult::False(),
                             bool *HasMissingTypename = 0);
 
+  /// \brief Determine whether an identifier has been tentatively declared as a
+  /// non-type. Such tentative declarations should not be found to name a type
+  /// during a tentative parse, but also should not be annotated as a non-type.
+  bool isTentativelyDeclared(IdentifierInfo *II);
+
   // "Tentative parsing" functions, used for disambiguation. If a parsing error
   // is encountered they will return TPResult::Error().
   // Returning TPResult::True()/False() indicates that the ambiguity was
diff --git a/include/clang/Sema/Sema.h b/include/clang/Sema/Sema.h
index acc88c0578..4f1b2f6aa9 100644
--- a/include/clang/Sema/Sema.h
+++ b/include/clang/Sema/Sema.h
@@ -1203,7 +1203,7 @@ public:
       assert(Kind == NC_TypeTemplate || Kind == NC_FunctionTemplate);
       return Kind == NC_TypeTemplate? TNK_Type_template : TNK_Function_template;
     }
-};
+  };
 
   /// \brief Perform name lookup on the given name, classifying it based on
   /// the results of name lookup and the following token.
@@ -1223,11 +1223,19 @@ public:
   ///
   /// \param NextToken The token following the identifier. Used to help
   /// disambiguate the name.
+  ///
+  /// \param IsAddressOfOperand True if this name is the operand of a unary
+  ///        address of ('&') expression, assuming it is classified as an
+  ///        expression.
+  ///
+  /// \param CCC The correction callback, if typo correction is desired.
   NameClassification ClassifyName(Scope *S,
                                   CXXScopeSpec &SS,
                                   IdentifierInfo *&Name,
                                   SourceLocation NameLoc,
-                                  const Token &NextToken);
+                                  const Token &NextToken,
+                                  bool IsAddressOfOperand,
+                                  CorrectionCandidateCallback *CCC = 0);
 
   Decl *ActOnDeclarator(Scope *S, Declarator &D);