--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tools/clang/lib/Parse/RAIIObjectsForParser.h	Thu Dec 12 13:56:28 2013 +0900
@@ -0,0 +1,435 @@
+//===--- RAIIObjectsForParser.h - RAII helpers for the parser ---*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines and implements the some simple RAII objects that are used
+// by the parser to manage bits in recursion.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_PARSE_RAII_OBJECTS_FOR_PARSER_H
+#define LLVM_CLANG_PARSE_RAII_OBJECTS_FOR_PARSER_H
+
+#include "clang/Parse/ParseDiagnostic.h"
+#include "clang/Parse/Parser.h"
+#include "clang/Sema/DelayedDiagnostic.h"
+#include "clang/Sema/Sema.h"
+
+namespace clang {
+  // TODO: move ParsingClassDefinition here.
+  // TODO: move TentativeParsingAction here.
+
+  /// \brief A RAII object used to temporarily suppress access-like
+  /// checking.  Access-like checks are those associated with
+  /// controlling the use of a declaration, like C++ access control
+  /// errors and deprecation warnings.  They are contextually
+  /// dependent, in that they can only be resolved with full
+  /// information about what's being declared.  They are also
+  /// suppressed in certain contexts, like the template arguments of
+  /// an explicit instantiation.  However, those suppression contexts
+  /// cannot necessarily be fully determined in advance;  for
+  /// example, something starting like this:
+  ///   template <> class std::vector<A::PrivateType>
+  /// might be the entirety of an explicit instantiation:
+  ///   template <> class std::vector<A::PrivateType>;
+  /// or just an elaborated type specifier:
+  ///   template <> class std::vector<A::PrivateType> make_vector<>();
+  /// Therefore this class collects all the diagnostics and permits
+  /// them to be re-delayed in a new context.
+  class SuppressAccessChecks {
+    Sema &S;
+    sema::DelayedDiagnosticPool DiagnosticPool;
+    Sema::ParsingDeclState State;
+    bool Active;
+
+  public:
+    /// Begin suppressing access-like checks 
+    SuppressAccessChecks(Parser &P, bool activate = true)
+        : S(P.getActions()), DiagnosticPool(NULL) {
+      if (activate) {
+        State = S.PushParsingDeclaration(DiagnosticPool);
+        Active = true;
+      } else {
+        Active = false;
+      }
+    }
+
+    void done() {
+      assert(Active && "trying to end an inactive suppression");
+      S.PopParsingDeclaration(State, NULL);
+      Active = false;
+    }
+
+    void redelay() {
+      assert(!Active && "redelaying without having ended first");
+      if (!DiagnosticPool.pool_empty())
+        S.redelayDiagnostics(DiagnosticPool);
+      assert(DiagnosticPool.pool_empty());
+    }
+
+    ~SuppressAccessChecks() {
+      if (Active) done();
+    }
+  };
+
+  /// \brief RAII object used to inform the actions that we're
+  /// currently parsing a declaration.  This is active when parsing a
+  /// variable's initializer, but not when parsing the body of a
+  /// class or function definition.
+  class ParsingDeclRAIIObject {
+    Sema &Actions;
+    sema::DelayedDiagnosticPool DiagnosticPool;
+    Sema::ParsingDeclState State;
+    bool Popped;
+
+    ParsingDeclRAIIObject(const ParsingDeclRAIIObject &) LLVM_DELETED_FUNCTION;
+    void operator=(const ParsingDeclRAIIObject &) LLVM_DELETED_FUNCTION;
+
+  public:
+    enum NoParent_t { NoParent };
+    ParsingDeclRAIIObject(Parser &P, NoParent_t _)
+        : Actions(P.getActions()), DiagnosticPool(NULL) {
+      push();
+    }
+
+    /// Creates a RAII object whose pool is optionally parented by another.
+    ParsingDeclRAIIObject(Parser &P,
+                          const sema::DelayedDiagnosticPool *parentPool)
+        : Actions(P.getActions()), DiagnosticPool(parentPool) {
+      push();
+    }
+
+    /// Creates a RAII object and, optionally, initialize its
+    /// diagnostics pool by stealing the diagnostics from another
+    /// RAII object (which is assumed to be the current top pool).
+    ParsingDeclRAIIObject(Parser &P, ParsingDeclRAIIObject *other)
+        : Actions(P.getActions()),
+          DiagnosticPool(other ? other->DiagnosticPool.getParent() : NULL) {
+      if (other) {
+        DiagnosticPool.steal(other->DiagnosticPool);
+        other->abort();
+      }
+      push();
+    }
+
+    ~ParsingDeclRAIIObject() {
+      abort();
+    }
+
+    sema::DelayedDiagnosticPool &getDelayedDiagnosticPool() {
+      return DiagnosticPool;
+    }
+    const sema::DelayedDiagnosticPool &getDelayedDiagnosticPool() const {
+      return DiagnosticPool;
+    }
+
+    /// Resets the RAII object for a new declaration.
+    void reset() {
+      abort();
+      push();
+    }
+
+    /// Signals that the context was completed without an appropriate
+    /// declaration being parsed.
+    void abort() {
+      pop(0);
+    }
+
+    void complete(Decl *D) {
+      assert(!Popped && "ParsingDeclaration has already been popped!");
+      pop(D);
+    }
+
+    /// Unregister this object from Sema, but remember all the
+    /// diagnostics that were emitted into it.
+    void abortAndRemember() {
+      pop(0);
+    }
+
+  private:
+    void push() {
+      State = Actions.PushParsingDeclaration(DiagnosticPool);
+      Popped = false;
+    }
+
+    void pop(Decl *D) {
+      if (!Popped) {
+        Actions.PopParsingDeclaration(State, D);
+        Popped = true;
+      }
+    }
+  };
+
+  /// A class for parsing a DeclSpec.
+  class ParsingDeclSpec : public DeclSpec {
+    ParsingDeclRAIIObject ParsingRAII;
+
+  public:
+    ParsingDeclSpec(Parser &P)
+      : DeclSpec(P.getAttrFactory()),
+        ParsingRAII(P, ParsingDeclRAIIObject::NoParent) {}
+    ParsingDeclSpec(Parser &P, ParsingDeclRAIIObject *RAII)
+      : DeclSpec(P.getAttrFactory()),
+        ParsingRAII(P, RAII) {}
+
+    const sema::DelayedDiagnosticPool &getDelayedDiagnosticPool() const {
+      return ParsingRAII.getDelayedDiagnosticPool();
+    }
+
+    void complete(Decl *D) {
+      ParsingRAII.complete(D);
+    }
+
+    void abort() {
+      ParsingRAII.abort();
+    }
+  };
+
+  /// A class for parsing a declarator.
+  class ParsingDeclarator : public Declarator {
+    ParsingDeclRAIIObject ParsingRAII;
+
+  public:
+    ParsingDeclarator(Parser &P, const ParsingDeclSpec &DS, TheContext C)
+      : Declarator(DS, C), ParsingRAII(P, &DS.getDelayedDiagnosticPool()) {
+    }
+
+    const ParsingDeclSpec &getDeclSpec() const {
+      return static_cast<const ParsingDeclSpec&>(Declarator::getDeclSpec());
+    }
+
+    ParsingDeclSpec &getMutableDeclSpec() const {
+      return const_cast<ParsingDeclSpec&>(getDeclSpec());
+    }
+
+    void clear() {
+      Declarator::clear();
+      ParsingRAII.reset();
+    }
+
+    void complete(Decl *D) {
+      ParsingRAII.complete(D);
+    }
+  };
+
+  /// A class for parsing a field declarator.
+  class ParsingFieldDeclarator : public FieldDeclarator {
+    ParsingDeclRAIIObject ParsingRAII;
+
+  public:
+    ParsingFieldDeclarator(Parser &P, const ParsingDeclSpec &DS)
+      : FieldDeclarator(DS), ParsingRAII(P, &DS.getDelayedDiagnosticPool()) {
+    }
+
+    const ParsingDeclSpec &getDeclSpec() const {
+      return static_cast<const ParsingDeclSpec&>(D.getDeclSpec());
+    }
+
+    ParsingDeclSpec &getMutableDeclSpec() const {
+      return const_cast<ParsingDeclSpec&>(getDeclSpec());
+    }
+
+    void complete(Decl *D) {
+      ParsingRAII.complete(D);
+    }
+  };
+
+  /// ExtensionRAIIObject - This saves the state of extension warnings when
+  /// constructed and disables them.  When destructed, it restores them back to
+  /// the way they used to be.  This is used to handle __extension__ in the
+  /// parser.
+  class ExtensionRAIIObject {
+    ExtensionRAIIObject(const ExtensionRAIIObject &) LLVM_DELETED_FUNCTION;
+    void operator=(const ExtensionRAIIObject &) LLVM_DELETED_FUNCTION;
+
+    DiagnosticsEngine &Diags;
+  public:
+    ExtensionRAIIObject(DiagnosticsEngine &diags) : Diags(diags) {
+      Diags.IncrementAllExtensionsSilenced();
+    }
+
+    ~ExtensionRAIIObject() {
+      Diags.DecrementAllExtensionsSilenced();
+    }
+  };
+  
+  /// ColonProtectionRAIIObject - This sets the Parser::ColonIsSacred bool and
+  /// restores it when destroyed.  This says that "foo:" should not be
+  /// considered a possible typo for "foo::" for error recovery purposes.
+  class ColonProtectionRAIIObject {
+    Parser &P;
+    bool OldVal;
+  public:
+    ColonProtectionRAIIObject(Parser &p, bool Value = true)
+      : P(p), OldVal(P.ColonIsSacred) {
+      P.ColonIsSacred = Value;
+    }
+    
+    /// restore - This can be used to restore the state early, before the dtor
+    /// is run.
+    void restore() {
+      P.ColonIsSacred = OldVal;
+    }
+    
+    ~ColonProtectionRAIIObject() {
+      restore();
+    }
+  };
+  
+  /// \brief RAII object that makes '>' behave either as an operator
+  /// or as the closing angle bracket for a template argument list.
+  class GreaterThanIsOperatorScope {
+    bool &GreaterThanIsOperator;
+    bool OldGreaterThanIsOperator;
+  public:
+    GreaterThanIsOperatorScope(bool &GTIO, bool Val)
+    : GreaterThanIsOperator(GTIO), OldGreaterThanIsOperator(GTIO) {
+      GreaterThanIsOperator = Val;
+    }
+    
+    ~GreaterThanIsOperatorScope() {
+      GreaterThanIsOperator = OldGreaterThanIsOperator;
+    }
+  };
+  
+  class InMessageExpressionRAIIObject {
+    bool &InMessageExpression;
+    bool OldValue;
+    
+  public:
+    InMessageExpressionRAIIObject(Parser &P, bool Value)
+      : InMessageExpression(P.InMessageExpression), 
+        OldValue(P.InMessageExpression) {
+      InMessageExpression = Value;
+    }
+    
+    ~InMessageExpressionRAIIObject() {
+      InMessageExpression = OldValue;
+    }
+  };
+  
+  /// \brief RAII object that makes sure paren/bracket/brace count is correct
+  /// after declaration/statement parsing, even when there's a parsing error.
+  class ParenBraceBracketBalancer {
+    Parser &P;
+    unsigned short ParenCount, BracketCount, BraceCount;
+  public:
+    ParenBraceBracketBalancer(Parser &p)
+      : P(p), ParenCount(p.ParenCount), BracketCount(p.BracketCount),
+        BraceCount(p.BraceCount) { }
+    
+    ~ParenBraceBracketBalancer() {
+      P.ParenCount = ParenCount;
+      P.BracketCount = BracketCount;
+      P.BraceCount = BraceCount;
+    }
+  };
+
+  class PoisonSEHIdentifiersRAIIObject {
+    PoisonIdentifierRAIIObject Ident_AbnormalTermination;
+    PoisonIdentifierRAIIObject Ident_GetExceptionCode;
+    PoisonIdentifierRAIIObject Ident_GetExceptionInfo;
+    PoisonIdentifierRAIIObject Ident__abnormal_termination;
+    PoisonIdentifierRAIIObject Ident__exception_code;
+    PoisonIdentifierRAIIObject Ident__exception_info;
+    PoisonIdentifierRAIIObject Ident___abnormal_termination;
+    PoisonIdentifierRAIIObject Ident___exception_code;
+    PoisonIdentifierRAIIObject Ident___exception_info;
+  public:
+    PoisonSEHIdentifiersRAIIObject(Parser &Self, bool NewValue)
+      : Ident_AbnormalTermination(Self.Ident_AbnormalTermination, NewValue),
+        Ident_GetExceptionCode(Self.Ident_GetExceptionCode, NewValue),
+        Ident_GetExceptionInfo(Self.Ident_GetExceptionInfo, NewValue),
+        Ident__abnormal_termination(Self.Ident__abnormal_termination, NewValue),
+        Ident__exception_code(Self.Ident__exception_code, NewValue),
+        Ident__exception_info(Self.Ident__exception_info, NewValue),
+        Ident___abnormal_termination(Self.Ident___abnormal_termination, NewValue),
+        Ident___exception_code(Self.Ident___exception_code, NewValue),
+        Ident___exception_info(Self.Ident___exception_info, NewValue) {
+    }
+  };
+
+  /// \brief RAII class that helps handle the parsing of an open/close delimiter
+  /// pair, such as braces { ... } or parentheses ( ... ).
+  class BalancedDelimiterTracker : public GreaterThanIsOperatorScope {
+    Parser& P;
+    tok::TokenKind Kind, Close, FinalToken;
+    SourceLocation (Parser::*Consumer)();
+    SourceLocation LOpen, LClose;
+    
+    unsigned short &getDepth() {
+      switch (Kind) {
+        case tok::l_brace: return P.BraceCount;
+        case tok::l_square: return P.BracketCount;
+        case tok::l_paren: return P.ParenCount;
+        default: llvm_unreachable("Wrong token kind");
+      }
+    }
+    
+    enum { MaxDepth = 256 };
+    
+    bool diagnoseOverflow();
+    bool diagnoseMissingClose();
+    
+  public:
+    BalancedDelimiterTracker(Parser& p, tok::TokenKind k,
+                             tok::TokenKind FinalToken = tok::semi)
+      : GreaterThanIsOperatorScope(p.GreaterThanIsOperator, true),
+        P(p), Kind(k), FinalToken(FinalToken)
+    {
+      switch (Kind) {
+        default: llvm_unreachable("Unexpected balanced token");
+        case tok::l_brace:
+          Close = tok::r_brace; 
+          Consumer = &Parser::ConsumeBrace;
+          break;
+        case tok::l_paren:
+          Close = tok::r_paren; 
+          Consumer = &Parser::ConsumeParen;
+          break;
+          
+        case tok::l_square:
+          Close = tok::r_square; 
+          Consumer = &Parser::ConsumeBracket;
+          break;
+      }      
+    }
+    
+    SourceLocation getOpenLocation() const { return LOpen; }
+    SourceLocation getCloseLocation() const { return LClose; }
+    SourceRange getRange() const { return SourceRange(LOpen, LClose); }
+    
+    bool consumeOpen() {
+      if (!P.Tok.is(Kind))
+        return true;
+      
+      if (getDepth() < P.getLangOpts().BracketDepth) {
+        LOpen = (P.*Consumer)();
+        return false;
+      }
+      
+      return diagnoseOverflow();
+    }
+    
+    bool expectAndConsume(unsigned DiagID,
+                          const char *Msg = "",
+                          tok::TokenKind SkipToTok = tok::unknown);
+    bool consumeClose() {
+      if (P.Tok.is(Close)) {
+        LClose = (P.*Consumer)();
+        return false;
+      } 
+      
+      return diagnoseMissingClose();
+    }
+    void skipToEnd();
+  };
+
+} // end namespace clang
+
+#endif