llvm-project/clang/lib/Parse/ParseTentative.cpp
John McCall 53fa71476d Refactor how we collect attributes during parsing, and add slots for attributes
on array and function declarators.  This is pretty far from complete, and I'll
revisit it later if someone doesn't beat me to it.

llvm-svn: 122535
2010-12-24 02:08:15 +00:00

1250 lines
38 KiB
C++

//===--- 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"
#include "clang/Sema/ParsedTemplate.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();
if (getLang().ObjC1 && Tok.is(tok::less))
TryParseProtocolQualifiers();
}
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() {
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) || isTokIdentifier_in()) {
// MSVC and g++ won't examine the rest of declarators if '=' is
// encountered; they just conclude that we have a declaration.
// EDG parses the initializer completely, which is the proper behavior
// for this case.
//
// At present, Clang follows MSVC and g++, since the parser does not have
// the ability to parse an expression fully without recording the
// results of that parse.
// Also allow 'in' after on objective-c declaration as in:
// for (int (^b)(void) in array). Ideally this should be done in the
// context of parsing for-init-statement of a foreach statement only. But,
// in any other context 'in' is invalid after a declaration and parser
// issues the error regardless of outcome of this decision.
// FIXME. Change if above assumption does not hold.
return TPResult::True();
}
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();
if (getLang().ObjC1 && Tok.is(tok::less))
TryParseProtocolQualifiers();
}
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();
if (getLang().ObjC1 && Tok.is(tok::less))
TryParseProtocolQualifiers();
}
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:
/// '...'[opt] 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))
if (TryAnnotateCXXScopeToken(true))
return TPResult::Error();
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::ellipsis))
ConsumeToken();
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) ||
Tok.is(tok::kw___declspec) ||
Tok.is(tok::kw___cdecl) ||
Tok.is(tok::kw___stdcall) ||
Tok.is(tok::kw___fastcall) ||
Tok.is(tok::kw___thiscall))
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());
// abstract-declarator: ...
if (Tok.is(tok::ellipsis))
ConsumeToken();
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();
}
Parser::TPResult
Parser::isExpressionOrTypeSpecifierSimple(tok::TokenKind Kind) {
switch (Kind) {
// Obviously starts an expression.
case tok::numeric_constant:
case tok::char_constant:
case tok::string_literal:
case tok::wide_string_literal:
case tok::l_square:
case tok::l_paren:
case tok::amp:
case tok::star:
case tok::plus:
case tok::plusplus:
case tok::minus:
case tok::minusminus:
case tok::tilde:
case tok::exclaim:
case tok::kw_sizeof:
case tok::kw___func__:
case tok::kw_const_cast:
case tok::kw_delete:
case tok::kw_dynamic_cast:
case tok::kw_false:
case tok::kw_new:
case tok::kw_operator:
case tok::kw_reinterpret_cast:
case tok::kw_static_cast:
case tok::kw_this:
case tok::kw_throw:
case tok::kw_true:
case tok::kw_typeid:
case tok::kw_alignof:
case tok::kw_noexcept:
case tok::kw_nullptr:
case tok::kw___null:
case tok::kw___alignof:
case tok::kw___builtin_choose_expr:
case tok::kw___builtin_offsetof:
case tok::kw___builtin_types_compatible_p:
case tok::kw___builtin_va_arg:
case tok::kw___imag:
case tok::kw___real:
case tok::kw___FUNCTION__:
case tok::kw___PRETTY_FUNCTION__:
case tok::kw___has_nothrow_assign:
case tok::kw___has_nothrow_copy:
case tok::kw___has_nothrow_constructor:
case tok::kw___has_trivial_assign:
case tok::kw___has_trivial_copy:
case tok::kw___has_trivial_constructor:
case tok::kw___has_trivial_destructor:
case tok::kw___has_virtual_destructor:
case tok::kw___is_abstract:
case tok::kw___is_base_of:
case tok::kw___is_class:
case tok::kw___is_empty:
case tok::kw___is_enum:
case tok::kw___is_pod:
case tok::kw___is_polymorphic:
case tok::kw___is_union:
case tok::kw___is_literal:
case tok::kw___uuidof:
return TPResult::True();
// Obviously starts a type-specifier-seq:
case tok::kw_char:
case tok::kw_const:
case tok::kw_double:
case tok::kw_enum:
case tok::kw_float:
case tok::kw_int:
case tok::kw_long:
case tok::kw_restrict:
case tok::kw_short:
case tok::kw_signed:
case tok::kw_struct:
case tok::kw_union:
case tok::kw_unsigned:
case tok::kw_void:
case tok::kw_volatile:
case tok::kw__Bool:
case tok::kw__Complex:
case tok::kw_class:
case tok::kw_typename:
case tok::kw_wchar_t:
case tok::kw_char16_t:
case tok::kw_char32_t:
case tok::kw_decltype:
case tok::kw_thread_local:
case tok::kw__Decimal32:
case tok::kw__Decimal64:
case tok::kw__Decimal128:
case tok::kw___thread:
case tok::kw_typeof:
case tok::kw___cdecl:
case tok::kw___stdcall:
case tok::kw___fastcall:
case tok::kw___thiscall:
case tok::kw___vector:
case tok::kw___pixel:
return TPResult::False();
default:
break;
}
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 TPResult::Error();
if (Tok.is(tok::identifier))
return TPResult::False();
return isCXXDeclarationSpecifier();
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 TPResult::Error();
return isCXXDeclarationSpecifier();
}
// 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___thiscall:
case tok::kw___w64:
case tok::kw___ptr64:
case tok::kw___forceinline:
return TPResult::True();
// Borland
case tok::kw___pascal:
return TPResult::True();
// AltiVec
case tok::kw___vector:
return TPResult::True();
case tok::annot_template_id: {
TemplateIdAnnotation *TemplateId
= static_cast<TemplateIdAnnotation *>(Tok.getAnnotationValue());
if (TemplateId->Kind != TNK_Type_template)
return TPResult::False();
CXXScopeSpec SS;
AnnotateTemplateIdTokenAsType(&SS);
assert(Tok.is(tok::annot_typename));
goto case_typename;
}
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())
return TPResult::Error();
if (!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::annot_typename:
case_typename:
// In Objective-C, we might have a protocol-qualified type.
if (getLang().ObjC1 && NextToken().is(tok::less)) {
// Tentatively parse the
TentativeParsingAction PA(*this);
ConsumeToken(); // The type token
TPResult TPR = TryParseProtocolQualifiers();
bool isFollowedByParen = Tok.is(tok::l_paren);
PA.Revert();
if (TPR == TPResult::Error())
return TPResult::Error();
if (isFollowedByParen)
return TPResult::Ambiguous();
return TPResult::True();
}
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:
if (NextToken().is(tok::l_paren))
return TPResult::Ambiguous();
if (isStartOfObjCClassMessageMissingOpenBracket())
return TPResult::False();
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();
}
/// [ObjC] protocol-qualifiers:
//// '<' identifier-list '>'
Parser::TPResult Parser::TryParseProtocolQualifiers() {
assert(Tok.is(tok::less) && "Expected '<' for qualifier list");
ConsumeToken();
do {
if (Tok.isNot(tok::identifier))
return TPResult::Error();
ConsumeToken();
if (Tok.is(tok::comma)) {
ConsumeToken();
continue;
}
if (Tok.is(tok::greater)) {
ConsumeToken();
return TPResult::Ambiguous();
}
} while (false);
return TPResult::Error();
}
Parser::TPResult Parser::TryParseDeclarationSpecifier() {
TPResult TPR = isCXXDeclarationSpecifier();
if (TPR != TPResult::Ambiguous())
return TPR;
if (Tok.is(tok::kw_typeof))
TryParseTypeofSpecifier();
else {
ConsumeToken();
if (getLang().ObjC1 && Tok.is(tok::less))
TryParseProtocolQualifiers();
}
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 attributes[opt]
/// decl-specifier-seq declarator attributes[opt] '=' assignment-expression
/// decl-specifier-seq abstract-declarator[opt] attributes[opt]
/// decl-specifier-seq abstract-declarator[opt] attributes[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.
}
ParsedAttributes attrs;
MaybeParseMicrosoftAttributes(attrs);
// 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;
// [GNU] attributes[opt]
if (Tok.is(tok::kw___attribute))
return TPResult::True();
if (Tok.is(tok::equal)) {
// '=' assignment-expression
// Parse through assignment-expression.
tok::TokenKind StopToks[2] ={ tok::comma, tok::r_paren };
if (!SkipUntil(StopToks, 2, 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();
}