Check in LLVM r95781.
diff --git a/lib/Parse/ParseTentative.cpp b/lib/Parse/ParseTentative.cpp
new file mode 100644
index 0000000..6251a2f
--- /dev/null
+++ b/lib/Parse/ParseTentative.cpp
@@ -0,0 +1,1035 @@
+//===--- ParseTentative.cpp - Ambiguity Resolution Parsing ----------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the tentative parsing portions of the Parser
+// interfaces, for ambiguity resolution.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Parse/Parser.h"
+#include "clang/Parse/ParseDiagnostic.h"
+using namespace clang;
+
+/// isCXXDeclarationStatement - C++-specialized function that disambiguates
+/// between a declaration or an expression statement, when parsing function
+/// bodies. Returns true for declaration, false for expression.
+///
+/// declaration-statement:
+/// block-declaration
+///
+/// block-declaration:
+/// simple-declaration
+/// asm-definition
+/// namespace-alias-definition
+/// using-declaration
+/// using-directive
+/// [C++0x] static_assert-declaration
+///
+/// asm-definition:
+/// 'asm' '(' string-literal ')' ';'
+///
+/// namespace-alias-definition:
+/// 'namespace' identifier = qualified-namespace-specifier ';'
+///
+/// using-declaration:
+/// 'using' typename[opt] '::'[opt] nested-name-specifier
+/// unqualified-id ';'
+/// 'using' '::' unqualified-id ;
+///
+/// using-directive:
+/// 'using' 'namespace' '::'[opt] nested-name-specifier[opt]
+/// namespace-name ';'
+///
+bool Parser::isCXXDeclarationStatement() {
+ switch (Tok.getKind()) {
+ // asm-definition
+ case tok::kw_asm:
+ // namespace-alias-definition
+ case tok::kw_namespace:
+ // using-declaration
+ // using-directive
+ case tok::kw_using:
+ // static_assert-declaration
+ case tok::kw_static_assert:
+ return true;
+ // simple-declaration
+ default:
+ return isCXXSimpleDeclaration();
+ }
+}
+
+/// isCXXSimpleDeclaration - C++-specialized function that disambiguates
+/// between a simple-declaration or an expression-statement.
+/// If during the disambiguation process a parsing error is encountered,
+/// the function returns true to let the declaration parsing code handle it.
+/// Returns false if the statement is disambiguated as expression.
+///
+/// simple-declaration:
+/// decl-specifier-seq init-declarator-list[opt] ';'
+///
+bool Parser::isCXXSimpleDeclaration() {
+ // C++ 6.8p1:
+ // There is an ambiguity in the grammar involving expression-statements and
+ // declarations: An expression-statement with a function-style explicit type
+ // conversion (5.2.3) as its leftmost subexpression can be indistinguishable
+ // from a declaration where the first declarator starts with a '('. In those
+ // cases the statement is a declaration. [Note: To disambiguate, the whole
+ // statement might have to be examined to determine if it is an
+ // expression-statement or a declaration].
+
+ // C++ 6.8p3:
+ // The disambiguation is purely syntactic; that is, the meaning of the names
+ // occurring in such a statement, beyond whether they are type-names or not,
+ // is not generally used in or changed by the disambiguation. Class
+ // templates are instantiated as necessary to determine if a qualified name
+ // is a type-name. Disambiguation precedes parsing, and a statement
+ // disambiguated as a declaration may be an ill-formed declaration.
+
+ // We don't have to parse all of the decl-specifier-seq part. There's only
+ // an ambiguity if the first decl-specifier is
+ // simple-type-specifier/typename-specifier followed by a '(', which may
+ // indicate a function-style cast expression.
+ // isCXXDeclarationSpecifier will return TPResult::Ambiguous() only in such
+ // a case.
+
+ TPResult TPR = isCXXDeclarationSpecifier();
+ if (TPR != TPResult::Ambiguous())
+ return TPR != TPResult::False(); // Returns true for TPResult::True() or
+ // TPResult::Error().
+
+ // FIXME: Add statistics about the number of ambiguous statements encountered
+ // and how they were resolved (number of declarations+number of expressions).
+
+ // Ok, we have a simple-type-specifier/typename-specifier followed by a '('.
+ // We need tentative parsing...
+
+ TentativeParsingAction PA(*this);
+
+ TPR = TryParseSimpleDeclaration();
+ SourceLocation TentativeParseLoc = Tok.getLocation();
+
+ PA.Revert();
+
+ // In case of an error, let the declaration parsing code handle it.
+ if (TPR == TPResult::Error())
+ return true;
+
+ // Declarations take precedence over expressions.
+ if (TPR == TPResult::Ambiguous())
+ TPR = TPResult::True();
+
+ assert(TPR == TPResult::True() || TPR == TPResult::False());
+ return TPR == TPResult::True();
+}
+
+/// simple-declaration:
+/// decl-specifier-seq init-declarator-list[opt] ';'
+///
+Parser::TPResult Parser::TryParseSimpleDeclaration() {
+ // We know that we have a simple-type-specifier/typename-specifier followed
+ // by a '('.
+ assert(isCXXDeclarationSpecifier() == TPResult::Ambiguous());
+
+ if (Tok.is(tok::kw_typeof))
+ TryParseTypeofSpecifier();
+ else
+ ConsumeToken();
+
+ assert(Tok.is(tok::l_paren) && "Expected '('");
+
+ TPResult TPR = TryParseInitDeclaratorList();
+ if (TPR != TPResult::Ambiguous())
+ return TPR;
+
+ if (Tok.isNot(tok::semi))
+ return TPResult::False();
+
+ return TPResult::Ambiguous();
+}
+
+/// init-declarator-list:
+/// init-declarator
+/// init-declarator-list ',' init-declarator
+///
+/// init-declarator:
+/// declarator initializer[opt]
+/// [GNU] declarator simple-asm-expr[opt] attributes[opt] initializer[opt]
+///
+/// initializer:
+/// '=' initializer-clause
+/// '(' expression-list ')'
+///
+/// initializer-clause:
+/// assignment-expression
+/// '{' initializer-list ','[opt] '}'
+/// '{' '}'
+///
+Parser::TPResult Parser::TryParseInitDeclaratorList() {
+ // GCC only examines the first declarator for disambiguation:
+ // i.e:
+ // int(x), ++x; // GCC regards it as ill-formed declaration.
+ //
+ // Comeau and MSVC will regard the above statement as correct expression.
+ // Clang examines all of the declarators and also regards the above statement
+ // as correct expression.
+
+ while (1) {
+ // declarator
+ TPResult TPR = TryParseDeclarator(false/*mayBeAbstract*/);
+ if (TPR != TPResult::Ambiguous())
+ return TPR;
+
+ // [GNU] simple-asm-expr[opt] attributes[opt]
+ if (Tok.is(tok::kw_asm) || Tok.is(tok::kw___attribute))
+ return TPResult::True();
+
+ // initializer[opt]
+ if (Tok.is(tok::l_paren)) {
+ // Parse through the parens.
+ ConsumeParen();
+ if (!SkipUntil(tok::r_paren))
+ return TPResult::Error();
+ } else if (Tok.is(tok::equal)) {
+ // MSVC won't examine the rest of declarators if '=' is encountered, it
+ // will conclude that it is a declaration.
+ // Comeau and Clang will examine the rest of declarators.
+ // Note that "int(x) = {0}, ++x;" will be interpreted as ill-formed
+ // expression.
+ //
+ // Parse through the initializer-clause.
+ SkipUntil(tok::comma, true/*StopAtSemi*/, true/*DontConsume*/);
+ }
+
+ if (Tok.isNot(tok::comma))
+ break;
+ ConsumeToken(); // the comma.
+ }
+
+ return TPResult::Ambiguous();
+}
+
+/// isCXXConditionDeclaration - Disambiguates between a declaration or an
+/// expression for a condition of a if/switch/while/for statement.
+/// If during the disambiguation process a parsing error is encountered,
+/// the function returns true to let the declaration parsing code handle it.
+///
+/// condition:
+/// expression
+/// type-specifier-seq declarator '=' assignment-expression
+/// [GNU] type-specifier-seq declarator simple-asm-expr[opt] attributes[opt]
+/// '=' assignment-expression
+///
+bool Parser::isCXXConditionDeclaration() {
+ TPResult TPR = isCXXDeclarationSpecifier();
+ if (TPR != TPResult::Ambiguous())
+ return TPR != TPResult::False(); // Returns true for TPResult::True() or
+ // TPResult::Error().
+
+ // FIXME: Add statistics about the number of ambiguous statements encountered
+ // and how they were resolved (number of declarations+number of expressions).
+
+ // Ok, we have a simple-type-specifier/typename-specifier followed by a '('.
+ // We need tentative parsing...
+
+ TentativeParsingAction PA(*this);
+
+ // type-specifier-seq
+ if (Tok.is(tok::kw_typeof))
+ TryParseTypeofSpecifier();
+ else
+ ConsumeToken();
+ assert(Tok.is(tok::l_paren) && "Expected '('");
+
+ // declarator
+ TPR = TryParseDeclarator(false/*mayBeAbstract*/);
+
+ // In case of an error, let the declaration parsing code handle it.
+ if (TPR == TPResult::Error())
+ TPR = TPResult::True();
+
+ if (TPR == TPResult::Ambiguous()) {
+ // '='
+ // [GNU] simple-asm-expr[opt] attributes[opt]
+ if (Tok.is(tok::equal) ||
+ Tok.is(tok::kw_asm) || Tok.is(tok::kw___attribute))
+ TPR = TPResult::True();
+ else
+ TPR = TPResult::False();
+ }
+
+ PA.Revert();
+
+ assert(TPR == TPResult::True() || TPR == TPResult::False());
+ return TPR == TPResult::True();
+}
+
+ /// \brief Determine whether the next set of tokens contains a type-id.
+ ///
+ /// The context parameter states what context we're parsing right
+ /// now, which affects how this routine copes with the token
+ /// following the type-id. If the context is TypeIdInParens, we have
+ /// already parsed the '(' and we will cease lookahead when we hit
+ /// the corresponding ')'. If the context is
+ /// TypeIdAsTemplateArgument, we've already parsed the '<' or ','
+ /// before this template argument, and will cease lookahead when we
+ /// hit a '>', '>>' (in C++0x), or ','. Returns true for a type-id
+ /// and false for an expression. If during the disambiguation
+ /// process a parsing error is encountered, the function returns
+ /// true to let the declaration parsing code handle it.
+ ///
+ /// type-id:
+ /// type-specifier-seq abstract-declarator[opt]
+ ///
+bool Parser::isCXXTypeId(TentativeCXXTypeIdContext Context, bool &isAmbiguous) {
+
+ isAmbiguous = false;
+
+ // C++ 8.2p2:
+ // The ambiguity arising from the similarity between a function-style cast and
+ // a type-id can occur in different contexts. The ambiguity appears as a
+ // choice between a function-style cast expression and a declaration of a
+ // type. The resolution is that any construct that could possibly be a type-id
+ // in its syntactic context shall be considered a type-id.
+
+ TPResult TPR = isCXXDeclarationSpecifier();
+ if (TPR != TPResult::Ambiguous())
+ return TPR != TPResult::False(); // Returns true for TPResult::True() or
+ // TPResult::Error().
+
+ // FIXME: Add statistics about the number of ambiguous statements encountered
+ // and how they were resolved (number of declarations+number of expressions).
+
+ // Ok, we have a simple-type-specifier/typename-specifier followed by a '('.
+ // We need tentative parsing...
+
+ TentativeParsingAction PA(*this);
+
+ // type-specifier-seq
+ if (Tok.is(tok::kw_typeof))
+ TryParseTypeofSpecifier();
+ else
+ ConsumeToken();
+ assert(Tok.is(tok::l_paren) && "Expected '('");
+
+ // declarator
+ TPR = TryParseDeclarator(true/*mayBeAbstract*/, false/*mayHaveIdentifier*/);
+
+ // In case of an error, let the declaration parsing code handle it.
+ if (TPR == TPResult::Error())
+ TPR = TPResult::True();
+
+ if (TPR == TPResult::Ambiguous()) {
+ // We are supposed to be inside parens, so if after the abstract declarator
+ // we encounter a ')' this is a type-id, otherwise it's an expression.
+ if (Context == TypeIdInParens && Tok.is(tok::r_paren)) {
+ TPR = TPResult::True();
+ isAmbiguous = true;
+
+ // We are supposed to be inside a template argument, so if after
+ // the abstract declarator we encounter a '>', '>>' (in C++0x), or
+ // ',', this is a type-id. Otherwise, it's an expression.
+ } else if (Context == TypeIdAsTemplateArgument &&
+ (Tok.is(tok::greater) || Tok.is(tok::comma) ||
+ (getLang().CPlusPlus0x && Tok.is(tok::greatergreater)))) {
+ TPR = TPResult::True();
+ isAmbiguous = true;
+
+ } else
+ TPR = TPResult::False();
+ }
+
+ PA.Revert();
+
+ assert(TPR == TPResult::True() || TPR == TPResult::False());
+ return TPR == TPResult::True();
+}
+
+/// isCXX0XAttributeSpecifier - returns true if this is a C++0x
+/// attribute-specifier. By default, unless in Obj-C++, only a cursory check is
+/// performed that will simply return true if a [[ is seen. Currently C++ has no
+/// syntactical ambiguities from this check, but it may inhibit error recovery.
+/// If CheckClosing is true, a check is made for closing ]] brackets.
+///
+/// If given, After is set to the token after the attribute-specifier so that
+/// appropriate parsing decisions can be made; it is left untouched if false is
+/// returned.
+///
+/// FIXME: If an error is in the closing ]] brackets, the program assumes
+/// the absence of an attribute-specifier, which can cause very yucky errors
+/// to occur.
+///
+/// [C++0x] attribute-specifier:
+/// '[' '[' attribute-list ']' ']'
+///
+/// [C++0x] attribute-list:
+/// attribute[opt]
+/// attribute-list ',' attribute[opt]
+///
+/// [C++0x] attribute:
+/// attribute-token attribute-argument-clause[opt]
+///
+/// [C++0x] attribute-token:
+/// identifier
+/// attribute-scoped-token
+///
+/// [C++0x] attribute-scoped-token:
+/// attribute-namespace '::' identifier
+///
+/// [C++0x] attribute-namespace:
+/// identifier
+///
+/// [C++0x] attribute-argument-clause:
+/// '(' balanced-token-seq ')'
+///
+/// [C++0x] balanced-token-seq:
+/// balanced-token
+/// balanced-token-seq balanced-token
+///
+/// [C++0x] balanced-token:
+/// '(' balanced-token-seq ')'
+/// '[' balanced-token-seq ']'
+/// '{' balanced-token-seq '}'
+/// any token but '(', ')', '[', ']', '{', or '}'
+bool Parser::isCXX0XAttributeSpecifier (bool CheckClosing,
+ tok::TokenKind *After) {
+ if (Tok.isNot(tok::l_square) || NextToken().isNot(tok::l_square))
+ return false;
+
+ // No tentative parsing if we don't need to look for ]]
+ if (!CheckClosing && !getLang().ObjC1)
+ return true;
+
+ struct TentativeReverter {
+ TentativeParsingAction PA;
+
+ TentativeReverter (Parser& P)
+ : PA(P)
+ {}
+ ~TentativeReverter () {
+ PA.Revert();
+ }
+ } R(*this);
+
+ // Opening brackets were checked for above.
+ ConsumeBracket();
+ ConsumeBracket();
+
+ // SkipUntil will handle balanced tokens, which are guaranteed in attributes.
+ SkipUntil(tok::r_square, false);
+
+ if (Tok.isNot(tok::r_square))
+ return false;
+ ConsumeBracket();
+
+ if (After)
+ *After = Tok.getKind();
+
+ return true;
+}
+
+/// declarator:
+/// direct-declarator
+/// ptr-operator declarator
+///
+/// direct-declarator:
+/// declarator-id
+/// direct-declarator '(' parameter-declaration-clause ')'
+/// cv-qualifier-seq[opt] exception-specification[opt]
+/// direct-declarator '[' constant-expression[opt] ']'
+/// '(' declarator ')'
+/// [GNU] '(' attributes declarator ')'
+///
+/// abstract-declarator:
+/// ptr-operator abstract-declarator[opt]
+/// direct-abstract-declarator
+///
+/// direct-abstract-declarator:
+/// direct-abstract-declarator[opt]
+/// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
+/// exception-specification[opt]
+/// direct-abstract-declarator[opt] '[' constant-expression[opt] ']'
+/// '(' abstract-declarator ')'
+///
+/// ptr-operator:
+/// '*' cv-qualifier-seq[opt]
+/// '&'
+/// [C++0x] '&&' [TODO]
+/// '::'[opt] nested-name-specifier '*' cv-qualifier-seq[opt]
+///
+/// cv-qualifier-seq:
+/// cv-qualifier cv-qualifier-seq[opt]
+///
+/// cv-qualifier:
+/// 'const'
+/// 'volatile'
+///
+/// declarator-id:
+/// id-expression
+///
+/// id-expression:
+/// unqualified-id
+/// qualified-id [TODO]
+///
+/// unqualified-id:
+/// identifier
+/// operator-function-id [TODO]
+/// conversion-function-id [TODO]
+/// '~' class-name [TODO]
+/// template-id [TODO]
+///
+Parser::TPResult Parser::TryParseDeclarator(bool mayBeAbstract,
+ bool mayHaveIdentifier) {
+ // declarator:
+ // direct-declarator
+ // ptr-operator declarator
+
+ while (1) {
+ if (Tok.is(tok::coloncolon) || Tok.is(tok::identifier))
+ TryAnnotateCXXScopeToken(true);
+
+ if (Tok.is(tok::star) || Tok.is(tok::amp) || Tok.is(tok::caret) ||
+ (Tok.is(tok::annot_cxxscope) && NextToken().is(tok::star))) {
+ // ptr-operator
+ ConsumeToken();
+ while (Tok.is(tok::kw_const) ||
+ Tok.is(tok::kw_volatile) ||
+ Tok.is(tok::kw_restrict))
+ ConsumeToken();
+ } else {
+ break;
+ }
+ }
+
+ // direct-declarator:
+ // direct-abstract-declarator:
+
+ if ((Tok.is(tok::identifier) ||
+ (Tok.is(tok::annot_cxxscope) && NextToken().is(tok::identifier))) &&
+ mayHaveIdentifier) {
+ // declarator-id
+ if (Tok.is(tok::annot_cxxscope))
+ ConsumeToken();
+ ConsumeToken();
+ } else if (Tok.is(tok::l_paren)) {
+ ConsumeParen();
+ if (mayBeAbstract &&
+ (Tok.is(tok::r_paren) || // 'int()' is a function.
+ Tok.is(tok::ellipsis) || // 'int(...)' is a function.
+ isDeclarationSpecifier())) { // 'int(int)' is a function.
+ // '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
+ // exception-specification[opt]
+ TPResult TPR = TryParseFunctionDeclarator();
+ if (TPR != TPResult::Ambiguous())
+ return TPR;
+ } else {
+ // '(' declarator ')'
+ // '(' attributes declarator ')'
+ // '(' abstract-declarator ')'
+ if (Tok.is(tok::kw___attribute))
+ return TPResult::True(); // attributes indicate declaration
+ TPResult TPR = TryParseDeclarator(mayBeAbstract, mayHaveIdentifier);
+ if (TPR != TPResult::Ambiguous())
+ return TPR;
+ if (Tok.isNot(tok::r_paren))
+ return TPResult::False();
+ ConsumeParen();
+ }
+ } else if (!mayBeAbstract) {
+ return TPResult::False();
+ }
+
+ while (1) {
+ TPResult TPR(TPResult::Ambiguous());
+
+ if (Tok.is(tok::l_paren)) {
+ // Check whether we have a function declarator or a possible ctor-style
+ // initializer that follows the declarator. Note that ctor-style
+ // initializers are not possible in contexts where abstract declarators
+ // are allowed.
+ if (!mayBeAbstract && !isCXXFunctionDeclarator(false/*warnIfAmbiguous*/))
+ break;
+
+ // direct-declarator '(' parameter-declaration-clause ')'
+ // cv-qualifier-seq[opt] exception-specification[opt]
+ ConsumeParen();
+ TPR = TryParseFunctionDeclarator();
+ } else if (Tok.is(tok::l_square)) {
+ // direct-declarator '[' constant-expression[opt] ']'
+ // direct-abstract-declarator[opt] '[' constant-expression[opt] ']'
+ TPR = TryParseBracketDeclarator();
+ } else {
+ break;
+ }
+
+ if (TPR != TPResult::Ambiguous())
+ return TPR;
+ }
+
+ return TPResult::Ambiguous();
+}
+
+/// isCXXDeclarationSpecifier - Returns TPResult::True() if it is a declaration
+/// specifier, TPResult::False() if it is not, TPResult::Ambiguous() if it could
+/// be either a decl-specifier or a function-style cast, and TPResult::Error()
+/// if a parsing error was found and reported.
+///
+/// decl-specifier:
+/// storage-class-specifier
+/// type-specifier
+/// function-specifier
+/// 'friend'
+/// 'typedef'
+/// [C++0x] 'constexpr'
+/// [GNU] attributes declaration-specifiers[opt]
+///
+/// storage-class-specifier:
+/// 'register'
+/// 'static'
+/// 'extern'
+/// 'mutable'
+/// 'auto'
+/// [GNU] '__thread'
+///
+/// function-specifier:
+/// 'inline'
+/// 'virtual'
+/// 'explicit'
+///
+/// typedef-name:
+/// identifier
+///
+/// type-specifier:
+/// simple-type-specifier
+/// class-specifier
+/// enum-specifier
+/// elaborated-type-specifier
+/// typename-specifier
+/// cv-qualifier
+///
+/// simple-type-specifier:
+/// '::'[opt] nested-name-specifier[opt] type-name
+/// '::'[opt] nested-name-specifier 'template'
+/// simple-template-id [TODO]
+/// 'char'
+/// 'wchar_t'
+/// 'bool'
+/// 'short'
+/// 'int'
+/// 'long'
+/// 'signed'
+/// 'unsigned'
+/// 'float'
+/// 'double'
+/// 'void'
+/// [GNU] typeof-specifier
+/// [GNU] '_Complex'
+/// [C++0x] 'auto' [TODO]
+/// [C++0x] 'decltype' ( expression )
+///
+/// type-name:
+/// class-name
+/// enum-name
+/// typedef-name
+///
+/// elaborated-type-specifier:
+/// class-key '::'[opt] nested-name-specifier[opt] identifier
+/// class-key '::'[opt] nested-name-specifier[opt] 'template'[opt]
+/// simple-template-id
+/// 'enum' '::'[opt] nested-name-specifier[opt] identifier
+///
+/// enum-name:
+/// identifier
+///
+/// enum-specifier:
+/// 'enum' identifier[opt] '{' enumerator-list[opt] '}'
+/// 'enum' identifier[opt] '{' enumerator-list ',' '}'
+///
+/// class-specifier:
+/// class-head '{' member-specification[opt] '}'
+///
+/// class-head:
+/// class-key identifier[opt] base-clause[opt]
+/// class-key nested-name-specifier identifier base-clause[opt]
+/// class-key nested-name-specifier[opt] simple-template-id
+/// base-clause[opt]
+///
+/// class-key:
+/// 'class'
+/// 'struct'
+/// 'union'
+///
+/// cv-qualifier:
+/// 'const'
+/// 'volatile'
+/// [GNU] restrict
+///
+Parser::TPResult Parser::isCXXDeclarationSpecifier() {
+ switch (Tok.getKind()) {
+ case tok::identifier: // foo::bar
+ // Check for need to substitute AltiVec __vector keyword
+ // for "vector" identifier.
+ if (TryAltiVecVectorToken())
+ return TPResult::True();
+ // Fall through.
+ case tok::kw_typename: // typename T::type
+ // Annotate typenames and C++ scope specifiers. If we get one, just
+ // recurse to handle whatever we get.
+ if (TryAnnotateTypeOrScopeToken())
+ return isCXXDeclarationSpecifier();
+ // Otherwise, not a typename.
+ return TPResult::False();
+
+ case tok::coloncolon: { // ::foo::bar
+ const Token &Next = NextToken();
+ if (Next.is(tok::kw_new) || // ::new
+ Next.is(tok::kw_delete)) // ::delete
+ return TPResult::False();
+
+ // Annotate typenames and C++ scope specifiers. If we get one, just
+ // recurse to handle whatever we get.
+ if (TryAnnotateTypeOrScopeToken())
+ return isCXXDeclarationSpecifier();
+ // Otherwise, not a typename.
+ return TPResult::False();
+ }
+
+ // decl-specifier:
+ // storage-class-specifier
+ // type-specifier
+ // function-specifier
+ // 'friend'
+ // 'typedef'
+ // 'constexpr'
+ case tok::kw_friend:
+ case tok::kw_typedef:
+ case tok::kw_constexpr:
+ // storage-class-specifier
+ case tok::kw_register:
+ case tok::kw_static:
+ case tok::kw_extern:
+ case tok::kw_mutable:
+ case tok::kw_auto:
+ case tok::kw___thread:
+ // function-specifier
+ case tok::kw_inline:
+ case tok::kw_virtual:
+ case tok::kw_explicit:
+
+ // type-specifier:
+ // simple-type-specifier
+ // class-specifier
+ // enum-specifier
+ // elaborated-type-specifier
+ // typename-specifier
+ // cv-qualifier
+
+ // class-specifier
+ // elaborated-type-specifier
+ case tok::kw_class:
+ case tok::kw_struct:
+ case tok::kw_union:
+ // enum-specifier
+ case tok::kw_enum:
+ // cv-qualifier
+ case tok::kw_const:
+ case tok::kw_volatile:
+
+ // GNU
+ case tok::kw_restrict:
+ case tok::kw__Complex:
+ case tok::kw___attribute:
+ return TPResult::True();
+
+ // Microsoft
+ case tok::kw___declspec:
+ case tok::kw___cdecl:
+ case tok::kw___stdcall:
+ case tok::kw___fastcall:
+ case tok::kw___w64:
+ case tok::kw___ptr64:
+ case tok::kw___forceinline:
+ return TPResult::True();
+
+ // AltiVec
+ case tok::kw___vector:
+ return TPResult::True();
+
+ case tok::annot_cxxscope: // foo::bar or ::foo::bar, but already parsed
+ // We've already annotated a scope; try to annotate a type.
+ if (!(TryAnnotateTypeOrScopeToken() && Tok.is(tok::annot_typename)))
+ return TPResult::False();
+ // If that succeeded, fallthrough into the generic simple-type-id case.
+
+ // The ambiguity resides in a simple-type-specifier/typename-specifier
+ // followed by a '('. The '(' could either be the start of:
+ //
+ // direct-declarator:
+ // '(' declarator ')'
+ //
+ // direct-abstract-declarator:
+ // '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
+ // exception-specification[opt]
+ // '(' abstract-declarator ')'
+ //
+ // or part of a function-style cast expression:
+ //
+ // simple-type-specifier '(' expression-list[opt] ')'
+ //
+
+ // simple-type-specifier:
+
+ case tok::kw_char:
+ case tok::kw_wchar_t:
+ case tok::kw_char16_t:
+ case tok::kw_char32_t:
+ case tok::kw_bool:
+ case tok::kw_short:
+ case tok::kw_int:
+ case tok::kw_long:
+ case tok::kw_signed:
+ case tok::kw_unsigned:
+ case tok::kw_float:
+ case tok::kw_double:
+ case tok::kw_void:
+ case tok::annot_typename:
+ if (NextToken().is(tok::l_paren))
+ return TPResult::Ambiguous();
+
+ return TPResult::True();
+
+ // GNU typeof support.
+ case tok::kw_typeof: {
+ if (NextToken().isNot(tok::l_paren))
+ return TPResult::True();
+
+ TentativeParsingAction PA(*this);
+
+ TPResult TPR = TryParseTypeofSpecifier();
+ bool isFollowedByParen = Tok.is(tok::l_paren);
+
+ PA.Revert();
+
+ if (TPR == TPResult::Error())
+ return TPResult::Error();
+
+ if (isFollowedByParen)
+ return TPResult::Ambiguous();
+
+ return TPResult::True();
+ }
+
+ // C++0x decltype support.
+ case tok::kw_decltype:
+ return TPResult::True();
+
+ default:
+ return TPResult::False();
+ }
+}
+
+/// [GNU] typeof-specifier:
+/// 'typeof' '(' expressions ')'
+/// 'typeof' '(' type-name ')'
+///
+Parser::TPResult Parser::TryParseTypeofSpecifier() {
+ assert(Tok.is(tok::kw_typeof) && "Expected 'typeof'!");
+ ConsumeToken();
+
+ assert(Tok.is(tok::l_paren) && "Expected '('");
+ // Parse through the parens after 'typeof'.
+ ConsumeParen();
+ if (!SkipUntil(tok::r_paren))
+ return TPResult::Error();
+
+ return TPResult::Ambiguous();
+}
+
+Parser::TPResult Parser::TryParseDeclarationSpecifier() {
+ TPResult TPR = isCXXDeclarationSpecifier();
+ if (TPR != TPResult::Ambiguous())
+ return TPR;
+
+ if (Tok.is(tok::kw_typeof))
+ TryParseTypeofSpecifier();
+ else
+ ConsumeToken();
+
+ assert(Tok.is(tok::l_paren) && "Expected '('!");
+ return TPResult::Ambiguous();
+}
+
+/// isCXXFunctionDeclarator - Disambiguates between a function declarator or
+/// a constructor-style initializer, when parsing declaration statements.
+/// Returns true for function declarator and false for constructor-style
+/// initializer.
+/// If during the disambiguation process a parsing error is encountered,
+/// the function returns true to let the declaration parsing code handle it.
+///
+/// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
+/// exception-specification[opt]
+///
+bool Parser::isCXXFunctionDeclarator(bool warnIfAmbiguous) {
+
+ // C++ 8.2p1:
+ // The ambiguity arising from the similarity between a function-style cast and
+ // a declaration mentioned in 6.8 can also occur in the context of a
+ // declaration. In that context, the choice is between a function declaration
+ // with a redundant set of parentheses around a parameter name and an object
+ // declaration with a function-style cast as the initializer. Just as for the
+ // ambiguities mentioned in 6.8, the resolution is to consider any construct
+ // that could possibly be a declaration a declaration.
+
+ TentativeParsingAction PA(*this);
+
+ ConsumeParen();
+ TPResult TPR = TryParseParameterDeclarationClause();
+ if (TPR == TPResult::Ambiguous() && Tok.isNot(tok::r_paren))
+ TPR = TPResult::False();
+
+ SourceLocation TPLoc = Tok.getLocation();
+ PA.Revert();
+
+ // In case of an error, let the declaration parsing code handle it.
+ if (TPR == TPResult::Error())
+ return true;
+
+ if (TPR == TPResult::Ambiguous()) {
+ // Function declarator has precedence over constructor-style initializer.
+ // Emit a warning just in case the author intended a variable definition.
+ if (warnIfAmbiguous)
+ Diag(Tok, diag::warn_parens_disambiguated_as_function_decl)
+ << SourceRange(Tok.getLocation(), TPLoc);
+ return true;
+ }
+
+ return TPR == TPResult::True();
+}
+
+/// parameter-declaration-clause:
+/// parameter-declaration-list[opt] '...'[opt]
+/// parameter-declaration-list ',' '...'
+///
+/// parameter-declaration-list:
+/// parameter-declaration
+/// parameter-declaration-list ',' parameter-declaration
+///
+/// parameter-declaration:
+/// decl-specifier-seq declarator
+/// decl-specifier-seq declarator '=' assignment-expression
+/// decl-specifier-seq abstract-declarator[opt]
+/// decl-specifier-seq abstract-declarator[opt] '=' assignment-expression
+///
+Parser::TPResult Parser::TryParseParameterDeclarationClause() {
+
+ if (Tok.is(tok::r_paren))
+ return TPResult::True();
+
+ // parameter-declaration-list[opt] '...'[opt]
+ // parameter-declaration-list ',' '...'
+ //
+ // parameter-declaration-list:
+ // parameter-declaration
+ // parameter-declaration-list ',' parameter-declaration
+ //
+ while (1) {
+ // '...'[opt]
+ if (Tok.is(tok::ellipsis)) {
+ ConsumeToken();
+ return TPResult::True(); // '...' is a sign of a function declarator.
+ }
+
+ // decl-specifier-seq
+ TPResult TPR = TryParseDeclarationSpecifier();
+ if (TPR != TPResult::Ambiguous())
+ return TPR;
+
+ // declarator
+ // abstract-declarator[opt]
+ TPR = TryParseDeclarator(true/*mayBeAbstract*/);
+ if (TPR != TPResult::Ambiguous())
+ return TPR;
+
+ if (Tok.is(tok::equal)) {
+ // '=' assignment-expression
+ // Parse through assignment-expression.
+ tok::TokenKind StopToks[3] ={ tok::comma, tok::ellipsis, tok::r_paren };
+ if (!SkipUntil(StopToks, 3, true/*StopAtSemi*/, true/*DontConsume*/))
+ return TPResult::Error();
+ }
+
+ if (Tok.is(tok::ellipsis)) {
+ ConsumeToken();
+ return TPResult::True(); // '...' is a sign of a function declarator.
+ }
+
+ if (Tok.isNot(tok::comma))
+ break;
+ ConsumeToken(); // the comma.
+ }
+
+ return TPResult::Ambiguous();
+}
+
+/// TryParseFunctionDeclarator - We parsed a '(' and we want to try to continue
+/// parsing as a function declarator.
+/// If TryParseFunctionDeclarator fully parsed the function declarator, it will
+/// return TPResult::Ambiguous(), otherwise it will return either False() or
+/// Error().
+///
+/// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
+/// exception-specification[opt]
+///
+/// exception-specification:
+/// 'throw' '(' type-id-list[opt] ')'
+///
+Parser::TPResult Parser::TryParseFunctionDeclarator() {
+
+ // The '(' is already parsed.
+
+ TPResult TPR = TryParseParameterDeclarationClause();
+ if (TPR == TPResult::Ambiguous() && Tok.isNot(tok::r_paren))
+ TPR = TPResult::False();
+
+ if (TPR == TPResult::False() || TPR == TPResult::Error())
+ return TPR;
+
+ // Parse through the parens.
+ if (!SkipUntil(tok::r_paren))
+ return TPResult::Error();
+
+ // cv-qualifier-seq
+ while (Tok.is(tok::kw_const) ||
+ Tok.is(tok::kw_volatile) ||
+ Tok.is(tok::kw_restrict) )
+ ConsumeToken();
+
+ // exception-specification
+ if (Tok.is(tok::kw_throw)) {
+ ConsumeToken();
+ if (Tok.isNot(tok::l_paren))
+ return TPResult::Error();
+
+ // Parse through the parens after 'throw'.
+ ConsumeParen();
+ if (!SkipUntil(tok::r_paren))
+ return TPResult::Error();
+ }
+
+ return TPResult::Ambiguous();
+}
+
+/// '[' constant-expression[opt] ']'
+///
+Parser::TPResult Parser::TryParseBracketDeclarator() {
+ ConsumeBracket();
+ if (!SkipUntil(tok::r_square))
+ return TPResult::Error();
+
+ return TPResult::Ambiguous();
+}