clang-1/Parse/ParseExpr.cpp

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//===--- ParseExpr.cpp - Expression Parsing -------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by Chris Lattner and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the Expression parsing implementation. Expressions in
// C99 basically consist of a bunch of binary operators with unary operators and
// other random stuff at the leaves.
//
// In the C99 grammar, these unary operators bind tightest and are represented
// as the 'cast-expression' production. Everything else is either a binary
// operator (e.g. '/') or a ternary operator ("?:"). The unary leaves are
// handled by ParseCastExpression, the higher level pieces are handled by
// ParseBinaryExpression.
//
//===----------------------------------------------------------------------===//
#include "clang/Parse/Parser.h"
#include "clang/Basic/Diagnostic.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/SmallString.h"
using namespace clang;
/// PrecedenceLevels - These are precedences for the binary/ternary operators in
/// the C99 grammar. These have been named to relate with the C99 grammar
/// productions. Low precedences numbers bind more weakly than high numbers.
namespace prec {
enum Level {
Unknown = 0, // Not binary operator.
Comma = 1, // ,
Assignment = 2, // =, *=, /=, %=, +=, -=, <<=, >>=, &=, ^=, |=
Conditional = 3, // ?
LogicalOr = 4, // ||
LogicalAnd = 5, // &&
InclusiveOr = 6, // |
ExclusiveOr = 7, // ^
And = 8, // &
Equality = 9, // ==, !=
Relational = 10, // >=, <=, >, <
Shift = 11, // <<, >>
Additive = 12, // -, +
Multiplicative = 13 // *, /, %
};
}
/// getBinOpPrecedence - Return the precedence of the specified binary operator
/// token. This returns:
///
static prec::Level getBinOpPrecedence(tok::TokenKind Kind) {
switch (Kind) {
default: return prec::Unknown;
case tok::comma: return prec::Comma;
case tok::equal:
case tok::starequal:
case tok::slashequal:
case tok::percentequal:
case tok::plusequal:
case tok::minusequal:
case tok::lesslessequal:
case tok::greatergreaterequal:
case tok::ampequal:
case tok::caretequal:
case tok::pipeequal: return prec::Assignment;
case tok::question: return prec::Conditional;
case tok::pipepipe: return prec::LogicalOr;
case tok::ampamp: return prec::LogicalAnd;
case tok::pipe: return prec::InclusiveOr;
case tok::caret: return prec::ExclusiveOr;
case tok::amp: return prec::And;
case tok::exclaimequal:
case tok::equalequal: return prec::Equality;
case tok::lessequal:
case tok::less:
case tok::greaterequal:
case tok::greater: return prec::Relational;
case tok::lessless:
case tok::greatergreater: return prec::Shift;
case tok::plus:
case tok::minus: return prec::Additive;
case tok::percent:
case tok::slash:
case tok::star: return prec::Multiplicative;
}
}
/// ParseExpression - Simple precedence-based parser for binary/ternary
/// operators.
///
/// Note: we diverge from the C99 grammar when parsing the assignment-expression
/// production. C99 specifies that the LHS of an assignment operator should be
/// parsed as a unary-expression, but consistency dictates that it be a
/// conditional-expession. In practice, the important thing here is that the
/// LHS of an assignment has to be an l-value, which productions between
/// unary-expression and conditional-expression don't produce. Because we want
/// consistency, we parse the LHS as a conditional-expression, then check for
/// l-value-ness in semantic analysis stages.
///
/// multiplicative-expression: [C99 6.5.5]
/// cast-expression
/// multiplicative-expression '*' cast-expression
/// multiplicative-expression '/' cast-expression
/// multiplicative-expression '%' cast-expression
///
/// additive-expression: [C99 6.5.6]
/// multiplicative-expression
/// additive-expression '+' multiplicative-expression
/// additive-expression '-' multiplicative-expression
///
/// shift-expression: [C99 6.5.7]
/// additive-expression
/// shift-expression '<<' additive-expression
/// shift-expression '>>' additive-expression
///
/// relational-expression: [C99 6.5.8]
/// shift-expression
/// relational-expression '<' shift-expression
/// relational-expression '>' shift-expression
/// relational-expression '<=' shift-expression
/// relational-expression '>=' shift-expression
///
/// equality-expression: [C99 6.5.9]
/// relational-expression
/// equality-expression '==' relational-expression
/// equality-expression '!=' relational-expression
///
/// AND-expression: [C99 6.5.10]
/// equality-expression
/// AND-expression '&' equality-expression
///
/// exclusive-OR-expression: [C99 6.5.11]
/// AND-expression
/// exclusive-OR-expression '^' AND-expression
///
/// inclusive-OR-expression: [C99 6.5.12]
/// exclusive-OR-expression
/// inclusive-OR-expression '|' exclusive-OR-expression
///
/// logical-AND-expression: [C99 6.5.13]
/// inclusive-OR-expression
/// logical-AND-expression '&&' inclusive-OR-expression
///
/// logical-OR-expression: [C99 6.5.14]
/// logical-AND-expression
/// logical-OR-expression '||' logical-AND-expression
///
/// conditional-expression: [C99 6.5.15]
/// logical-OR-expression
/// logical-OR-expression '?' expression ':' conditional-expression
/// [GNU] logical-OR-expression '?' ':' conditional-expression
///
/// assignment-expression: [C99 6.5.16]
/// conditional-expression
/// unary-expression assignment-operator assignment-expression
///
/// assignment-operator: one of
/// = *= /= %= += -= <<= >>= &= ^= |=
///
/// expression: [C99 6.5.17]
/// assignment-expression
/// expression ',' assignment-expression
///
Parser::ExprResult Parser::ParseExpression() {
ExprResult LHS = ParseCastExpression(false);
if (LHS.isInvalid) return LHS;
return ParseRHSOfBinaryExpression(LHS, prec::Comma);
}
/// This routine is called when the '@' is seen and consumed.
/// Current token is an Identifier and is not a 'try'. This
/// routine is necessary to disambiguate @try-statement from,
/// for example, @encode-expression.
///
Parser::ExprResult Parser::ParseExpressionWithLeadingAt(SourceLocation AtLoc) {
ExprResult LHS = ParseObjCExpression(AtLoc);
if (LHS.isInvalid) return LHS;
return ParseRHSOfBinaryExpression(LHS, prec::Comma);
}
/// ParseAssignmentExpression - Parse an expr that doesn't include commas.
///
Parser::ExprResult Parser::ParseAssignmentExpression() {
ExprResult LHS = ParseCastExpression(false);
if (LHS.isInvalid) return LHS;
return ParseRHSOfBinaryExpression(LHS, prec::Assignment);
}
Parser::ExprResult Parser::ParseConstantExpression() {
ExprResult LHS = ParseCastExpression(false);
if (LHS.isInvalid) return LHS;
// TODO: Validate that this is a constant expr!
return ParseRHSOfBinaryExpression(LHS, prec::Conditional);
}
/// ParseExpressionWithLeadingIdentifier - This special purpose method is used
/// in contexts where we have already consumed an identifier (which we saved in
/// 'IdTok'), then discovered that the identifier was really the leading token
/// of part of an expression. For example, in "A[1]+B", we consumed "A" (which
/// is now in 'IdTok') and the current token is "[".
Parser::ExprResult Parser::
ParseExpressionWithLeadingIdentifier(const Token &IdTok) {
// We know that 'IdTok' must correspond to this production:
// primary-expression: identifier
// Let the actions module handle the identifier.
ExprResult Res = Actions.ActOnIdentifierExpr(CurScope, IdTok.getLocation(),
*IdTok.getIdentifierInfo(),
Tok.is(tok::l_paren));
// Because we have to parse an entire cast-expression before starting the
// ParseRHSOfBinaryExpression method (which parses any trailing binops), we
// need to handle the 'postfix-expression' rules. We do this by invoking
// ParsePostfixExpressionSuffix to consume any postfix-expression suffixes:
Res = ParsePostfixExpressionSuffix(Res);
if (Res.isInvalid) return Res;
// At this point, the "A[1]" part of "A[1]+B" has been consumed. Once this is
// done, we know we don't have to do anything for cast-expression, because the
// only non-postfix-expression production starts with a '(' token, and we know
// we have an identifier. As such, we can invoke ParseRHSOfBinaryExpression
// to consume any trailing operators (e.g. "+" in this example) and connected
// chunks of the expression.
return ParseRHSOfBinaryExpression(Res, prec::Comma);
}
/// ParseExpressionWithLeadingIdentifier - This special purpose method is used
/// in contexts where we have already consumed an identifier (which we saved in
/// 'IdTok'), then discovered that the identifier was really the leading token
/// of part of an assignment-expression. For example, in "A[1]+B", we consumed
/// "A" (which is now in 'IdTok') and the current token is "[".
Parser::ExprResult Parser::
ParseAssignmentExprWithLeadingIdentifier(const Token &IdTok) {
// We know that 'IdTok' must correspond to this production:
// primary-expression: identifier
// Let the actions module handle the identifier.
ExprResult Res = Actions.ActOnIdentifierExpr(CurScope, IdTok.getLocation(),
*IdTok.getIdentifierInfo(),
Tok.is(tok::l_paren));
// Because we have to parse an entire cast-expression before starting the
// ParseRHSOfBinaryExpression method (which parses any trailing binops), we
// need to handle the 'postfix-expression' rules. We do this by invoking
// ParsePostfixExpressionSuffix to consume any postfix-expression suffixes:
Res = ParsePostfixExpressionSuffix(Res);
if (Res.isInvalid) return Res;
// At this point, the "A[1]" part of "A[1]+B" has been consumed. Once this is
// done, we know we don't have to do anything for cast-expression, because the
// only non-postfix-expression production starts with a '(' token, and we know
// we have an identifier. As such, we can invoke ParseRHSOfBinaryExpression
// to consume any trailing operators (e.g. "+" in this example) and connected
// chunks of the expression.
return ParseRHSOfBinaryExpression(Res, prec::Assignment);
}
/// ParseAssignmentExpressionWithLeadingStar - This special purpose method is
/// used in contexts where we have already consumed a '*' (which we saved in
/// 'StarTok'), then discovered that the '*' was really the leading token of an
/// expression. For example, in "*(int*)P+B", we consumed "*" (which is
/// now in 'StarTok') and the current token is "(".
Parser::ExprResult Parser::
ParseAssignmentExpressionWithLeadingStar(const Token &StarTok) {
// We know that 'StarTok' must correspond to this production:
// unary-expression: unary-operator cast-expression
// where 'unary-operator' is '*'.
// Parse the cast-expression that follows the '*'. This will parse the
// "*(int*)P" part of "*(int*)P+B".
ExprResult Res = ParseCastExpression(false);
if (Res.isInvalid) return Res;
// Combine StarTok + Res to get the new AST for the combined expression..
Res = Actions.ActOnUnaryOp(StarTok.getLocation(), tok::star, Res.Val);
if (Res.isInvalid) return Res;
// We have to parse an entire cast-expression before starting the
// ParseRHSOfBinaryExpression method (which parses any trailing binops). Since
// we know that the only production above us is the cast-expression
// production, and because the only alternative productions start with a '('
// token (we know we had a '*'), there is no work to do to get a whole
// cast-expression.
// At this point, the "*(int*)P" part of "*(int*)P+B" has been consumed. Once
// this is done, we can invoke ParseRHSOfBinaryExpression to consume any
// trailing operators (e.g. "+" in this example) and connected chunks of the
// assignment-expression.
return ParseRHSOfBinaryExpression(Res, prec::Assignment);
}
/// ParseRHSOfBinaryExpression - Parse a binary expression that starts with
/// LHS and has a precedence of at least MinPrec.
Parser::ExprResult
Parser::ParseRHSOfBinaryExpression(ExprResult LHS, unsigned MinPrec) {
unsigned NextTokPrec = getBinOpPrecedence(Tok.getKind());
SourceLocation ColonLoc;
while (1) {
// If this token has a lower precedence than we are allowed to parse (e.g.
// because we are called recursively, or because the token is not a binop),
// then we are done!
if (NextTokPrec < MinPrec)
return LHS;
// Consume the operator, saving the operator token for error reporting.
Token OpToken = Tok;
ConsumeToken();
// Special case handling for the ternary operator.
ExprResult TernaryMiddle(true);
if (NextTokPrec == prec::Conditional) {
if (Tok.isNot(tok::colon)) {
// Handle this production specially:
// logical-OR-expression '?' expression ':' conditional-expression
// In particular, the RHS of the '?' is 'expression', not
// 'logical-OR-expression' as we might expect.
TernaryMiddle = ParseExpression();
if (TernaryMiddle.isInvalid) {
Actions.DeleteExpr(LHS.Val);
return TernaryMiddle;
}
} else {
// Special case handling of "X ? Y : Z" where Y is empty:
// logical-OR-expression '?' ':' conditional-expression [GNU]
TernaryMiddle = ExprResult(false);
Diag(Tok, diag::ext_gnu_conditional_expr);
}
if (Tok.isNot(tok::colon)) {
Diag(Tok, diag::err_expected_colon);
Diag(OpToken, diag::err_matching, "?");
Actions.DeleteExpr(LHS.Val);
Actions.DeleteExpr(TernaryMiddle.Val);
return ExprResult(true);
}
// Eat the colon.
ColonLoc = ConsumeToken();
}
// Parse another leaf here for the RHS of the operator.
ExprResult RHS = ParseCastExpression(false);
if (RHS.isInvalid) {
Actions.DeleteExpr(LHS.Val);
Actions.DeleteExpr(TernaryMiddle.Val);
return RHS;
}
// Remember the precedence of this operator and get the precedence of the
// operator immediately to the right of the RHS.
unsigned ThisPrec = NextTokPrec;
NextTokPrec = getBinOpPrecedence(Tok.getKind());
// Assignment and conditional expressions are right-associative.
bool isRightAssoc = NextTokPrec == prec::Conditional ||
NextTokPrec == prec::Assignment;
// Get the precedence of the operator to the right of the RHS. If it binds
// more tightly with RHS than we do, evaluate it completely first.
if (ThisPrec < NextTokPrec ||
(ThisPrec == NextTokPrec && isRightAssoc)) {
// If this is left-associative, only parse things on the RHS that bind
// more tightly than the current operator. If it is left-associative, it
// is okay, to bind exactly as tightly. For example, compile A=B=C=D as
// A=(B=(C=D)), where each paren is a level of recursion here.
RHS = ParseRHSOfBinaryExpression(RHS, ThisPrec + !isRightAssoc);
if (RHS.isInvalid) {
Actions.DeleteExpr(LHS.Val);
Actions.DeleteExpr(TernaryMiddle.Val);
return RHS;
}
NextTokPrec = getBinOpPrecedence(Tok.getKind());
}
assert(NextTokPrec <= ThisPrec && "Recursion didn't work!");
if (!LHS.isInvalid) {
// Combine the LHS and RHS into the LHS (e.g. build AST).
if (TernaryMiddle.isInvalid)
LHS = Actions.ActOnBinOp(OpToken.getLocation(), OpToken.getKind(),
LHS.Val, RHS.Val);
else
LHS = Actions.ActOnConditionalOp(OpToken.getLocation(), ColonLoc,
LHS.Val, TernaryMiddle.Val, RHS.Val);
} else {
// We had a semantic error on the LHS. Just free the RHS and continue.
Actions.DeleteExpr(TernaryMiddle.Val);
Actions.DeleteExpr(RHS.Val);
}
}
}
/// ParseCastExpression - Parse a cast-expression, or, if isUnaryExpression is
/// true, parse a unary-expression.
///
/// cast-expression: [C99 6.5.4]
/// unary-expression
/// '(' type-name ')' cast-expression
///
/// unary-expression: [C99 6.5.3]
/// postfix-expression
/// '++' unary-expression
/// '--' unary-expression
/// unary-operator cast-expression
/// 'sizeof' unary-expression
/// 'sizeof' '(' type-name ')'
/// [GNU] '__alignof' unary-expression
/// [GNU] '__alignof' '(' type-name ')'
/// [GNU] '&&' identifier
///
/// unary-operator: one of
/// '&' '*' '+' '-' '~' '!'
/// [GNU] '__extension__' '__real' '__imag'
///
/// primary-expression: [C99 6.5.1]
/// identifier
/// constant
/// string-literal
/// [C++] boolean-literal [C++ 2.13.5]
/// '(' expression ')'
/// '__func__' [C99 6.4.2.2]
/// [GNU] '__FUNCTION__'
/// [GNU] '__PRETTY_FUNCTION__'
/// [GNU] '(' compound-statement ')'
/// [GNU] '__builtin_va_arg' '(' assignment-expression ',' type-name ')'
/// [GNU] '__builtin_offsetof' '(' type-name ',' offsetof-member-designator')'
/// [GNU] '__builtin_choose_expr' '(' assign-expr ',' assign-expr ','
/// assign-expr ')'
/// [GNU] '__builtin_types_compatible_p' '(' type-name ',' type-name ')'
/// [OBJC] '[' objc-message-expr ']'
/// [OBJC] '@selector' '(' objc-selector-arg ')' [TODO]
/// [OBJC] '@protocol' '(' identifier ')'
/// [OBJC] '@encode' '(' type-name ')'
/// [OBJC] objc-string-literal
/// [C++] 'const_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1]
/// [C++] 'dynamic_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1]
/// [C++] 'reinterpret_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1]
/// [C++] 'static_cast' '<' type-name '>' '(' expression ')' [C++ 5.2p1]
///
/// constant: [C99 6.4.4]
/// integer-constant
/// floating-constant
/// enumeration-constant -> identifier
/// character-constant
///
Parser::ExprResult Parser::ParseCastExpression(bool isUnaryExpression) {
ExprResult Res;
tok::TokenKind SavedKind = Tok.getKind();
// This handles all of cast-expression, unary-expression, postfix-expression,
// and primary-expression. We handle them together like this for efficiency
// and to simplify handling of an expression starting with a '(' token: which
// may be one of a parenthesized expression, cast-expression, compound literal
// expression, or statement expression.
//
// If the parsed tokens consist of a primary-expression, the cases below
// call ParsePostfixExpressionSuffix to handle the postfix expression
// suffixes. Cases that cannot be followed by postfix exprs should
// return without invoking ParsePostfixExpressionSuffix.
switch (SavedKind) {
case tok::l_paren: {
// If this expression is limited to being a unary-expression, the parent can
// not start a cast expression.
ParenParseOption ParenExprType =
isUnaryExpression ? CompoundLiteral : CastExpr;
TypeTy *CastTy;
SourceLocation LParenLoc = Tok.getLocation();
SourceLocation RParenLoc;
Res = ParseParenExpression(ParenExprType, CastTy, RParenLoc);
if (Res.isInvalid) return Res;
switch (ParenExprType) {
case SimpleExpr: break; // Nothing else to do.
case CompoundStmt: break; // Nothing else to do.
case CompoundLiteral:
// We parsed '(' type-name ')' '{' ... '}'. If any suffixes of
// postfix-expression exist, parse them now.
break;
case CastExpr:
// We parsed '(' type-name ')' and the thing after it wasn't a '{'. Parse
// the cast-expression that follows it next.
// TODO: For cast expression with CastTy.
Res = ParseCastExpression(false);
if (!Res.isInvalid)
Res = Actions.ActOnCastExpr(LParenLoc, CastTy, RParenLoc, Res.Val);
return Res;
}
// These can be followed by postfix-expr pieces.
return ParsePostfixExpressionSuffix(Res);
}
// primary-expression
case tok::numeric_constant:
// constant: integer-constant
// constant: floating-constant
Res = Actions.ActOnNumericConstant(Tok);
ConsumeToken();
// These can be followed by postfix-expr pieces.
return ParsePostfixExpressionSuffix(Res);
case tok::kw_true:
case tok::kw_false:
return ParseCXXBoolLiteral();
case tok::identifier: { // primary-expression: identifier
// constant: enumeration-constant
// Consume the identifier so that we can see if it is followed by a '('.
// Function designators are allowed to be undeclared (C99 6.5.1p2), so we
// need to know whether or not this identifier is a function designator or
// not.
IdentifierInfo &II = *Tok.getIdentifierInfo();
SourceLocation L = ConsumeToken();
Res = Actions.ActOnIdentifierExpr(CurScope, L, II, Tok.is(tok::l_paren));
// These can be followed by postfix-expr pieces.
return ParsePostfixExpressionSuffix(Res);
}
case tok::char_constant: // constant: character-constant
Res = Actions.ActOnCharacterConstant(Tok);
ConsumeToken();
// These can be followed by postfix-expr pieces.
return ParsePostfixExpressionSuffix(Res);
case tok::kw___func__: // primary-expression: __func__ [C99 6.4.2.2]
case tok::kw___FUNCTION__: // primary-expression: __FUNCTION__ [GNU]
case tok::kw___PRETTY_FUNCTION__: // primary-expression: __P..Y_F..N__ [GNU]
Res = Actions.ActOnPreDefinedExpr(Tok.getLocation(), SavedKind);
ConsumeToken();
// These can be followed by postfix-expr pieces.
return ParsePostfixExpressionSuffix(Res);
case tok::string_literal: // primary-expression: string-literal
case tok::wide_string_literal:
Res = ParseStringLiteralExpression();
if (Res.isInvalid) return Res;
// This can be followed by postfix-expr pieces (e.g. "foo"[1]).
return ParsePostfixExpressionSuffix(Res);
case tok::kw___builtin_va_arg:
case tok::kw___builtin_offsetof:
case tok::kw___builtin_choose_expr:
case tok::kw___builtin_types_compatible_p:
return ParseBuiltinPrimaryExpression();
case tok::plusplus: // unary-expression: '++' unary-expression
case tok::minusminus: { // unary-expression: '--' unary-expression
SourceLocation SavedLoc = ConsumeToken();
Res = ParseCastExpression(true);
if (!Res.isInvalid)
Res = Actions.ActOnUnaryOp(SavedLoc, SavedKind, Res.Val);
return Res;
}
case tok::amp: // unary-expression: '&' cast-expression
case tok::star: // unary-expression: '*' cast-expression
case tok::plus: // unary-expression: '+' cast-expression
case tok::minus: // unary-expression: '-' cast-expression
case tok::tilde: // unary-expression: '~' cast-expression
case tok::exclaim: // unary-expression: '!' cast-expression
case tok::kw___real: // unary-expression: '__real' cast-expression [GNU]
case tok::kw___imag: // unary-expression: '__imag' cast-expression [GNU]
case tok::kw___extension__:{//unary-expression:'__extension__' cast-expr [GNU]
// FIXME: Extension should silence extwarns in subexpressions.
SourceLocation SavedLoc = ConsumeToken();
Res = ParseCastExpression(false);
if (!Res.isInvalid)
Res = Actions.ActOnUnaryOp(SavedLoc, SavedKind, Res.Val);
return Res;
}
case tok::kw_sizeof: // unary-expression: 'sizeof' unary-expression
// unary-expression: 'sizeof' '(' type-name ')'
case tok::kw___alignof: // unary-expression: '__alignof' unary-expression
// unary-expression: '__alignof' '(' type-name ')'
return ParseSizeofAlignofExpression();
case tok::ampamp: { // unary-expression: '&&' identifier
SourceLocation AmpAmpLoc = ConsumeToken();
if (Tok.isNot(tok::identifier)) {
Diag(Tok, diag::err_expected_ident);
return ExprResult(true);
}
Diag(AmpAmpLoc, diag::ext_gnu_address_of_label);
Res = Actions.ActOnAddrLabel(AmpAmpLoc, Tok.getLocation(),
Tok.getIdentifierInfo());
ConsumeToken();
return Res;
}
case tok::kw_const_cast:
case tok::kw_dynamic_cast:
case tok::kw_reinterpret_cast:
case tok::kw_static_cast:
return ParseCXXCasts();
case tok::at: {
SourceLocation AtLoc = ConsumeToken();
return ParseObjCExpression(AtLoc);
}
case tok::l_square:
return ParseObjCMessageExpression();
default:
Diag(Tok, diag::err_expected_expression);
return ExprResult(true);
}
// unreachable.
abort();
}
/// ParsePostfixExpressionSuffix - Once the leading part of a postfix-expression
/// is parsed, this method parses any suffixes that apply.
///
/// postfix-expression: [C99 6.5.2]
/// primary-expression
/// postfix-expression '[' expression ']'
/// postfix-expression '(' argument-expression-list[opt] ')'
/// postfix-expression '.' identifier
/// postfix-expression '->' identifier
/// postfix-expression '++'
/// postfix-expression '--'
/// '(' type-name ')' '{' initializer-list '}'
/// '(' type-name ')' '{' initializer-list ',' '}'
///
/// argument-expression-list: [C99 6.5.2]
/// argument-expression
/// argument-expression-list ',' assignment-expression
///
Parser::ExprResult Parser::ParsePostfixExpressionSuffix(ExprResult LHS) {
// Now that the primary-expression piece of the postfix-expression has been
// parsed, see if there are any postfix-expression pieces here.
SourceLocation Loc;
while (1) {
switch (Tok.getKind()) {
default: // Not a postfix-expression suffix.
return LHS;
case tok::l_square: { // postfix-expression: p-e '[' expression ']'
Loc = ConsumeBracket();
ExprResult Idx = ParseExpression();
SourceLocation RLoc = Tok.getLocation();
if (!LHS.isInvalid && !Idx.isInvalid && Tok.is(tok::r_square))
LHS = Actions.ActOnArraySubscriptExpr(LHS.Val, Loc, Idx.Val, RLoc);
else
LHS = ExprResult(true);
// Match the ']'.
MatchRHSPunctuation(tok::r_square, Loc);
break;
}
case tok::l_paren: { // p-e: p-e '(' argument-expression-list[opt] ')'
llvm::SmallVector<ExprTy*, 8> ArgExprs;
llvm::SmallVector<SourceLocation, 8> CommaLocs;
Loc = ConsumeParen();
if (Tok.isNot(tok::r_paren)) {
while (1) {
ExprResult ArgExpr = ParseAssignmentExpression();
if (ArgExpr.isInvalid) {
SkipUntil(tok::r_paren);
return ExprResult(true);
} else
ArgExprs.push_back(ArgExpr.Val);
if (Tok.isNot(tok::comma))
break;
// Move to the next argument, remember where the comma was.
CommaLocs.push_back(ConsumeToken());
}
}
// Match the ')'.
if (!LHS.isInvalid && Tok.is(tok::r_paren)) {
assert((ArgExprs.size() == 0 || ArgExprs.size()-1 == CommaLocs.size())&&
"Unexpected number of commas!");
LHS = Actions.ActOnCallExpr(LHS.Val, Loc, &ArgExprs[0], ArgExprs.size(),
&CommaLocs[0], Tok.getLocation());
}
MatchRHSPunctuation(tok::r_paren, Loc);
break;
}
case tok::arrow: // postfix-expression: p-e '->' identifier
case tok::period: { // postfix-expression: p-e '.' identifier
tok::TokenKind OpKind = Tok.getKind();
SourceLocation OpLoc = ConsumeToken(); // Eat the "." or "->" token.
if (Tok.isNot(tok::identifier)) {
Diag(Tok, diag::err_expected_ident);
return ExprResult(true);
}
if (!LHS.isInvalid)
LHS = Actions.ActOnMemberReferenceExpr(LHS.Val, OpLoc, OpKind,
Tok.getLocation(),
*Tok.getIdentifierInfo());
ConsumeToken();
break;
}
case tok::plusplus: // postfix-expression: postfix-expression '++'
case tok::minusminus: // postfix-expression: postfix-expression '--'
if (!LHS.isInvalid)
LHS = Actions.ActOnPostfixUnaryOp(Tok.getLocation(), Tok.getKind(),
LHS.Val);
ConsumeToken();
break;
}
}
}
/// ParseSizeofAlignofExpression - Parse a sizeof or alignof expression.
/// unary-expression: [C99 6.5.3]
/// 'sizeof' unary-expression
/// 'sizeof' '(' type-name ')'
/// [GNU] '__alignof' unary-expression
/// [GNU] '__alignof' '(' type-name ')'
Parser::ExprResult Parser::ParseSizeofAlignofExpression() {
assert((Tok.is(tok::kw_sizeof) || Tok.is(tok::kw___alignof)) &&
"Not a sizeof/alignof expression!");
Token OpTok = Tok;
ConsumeToken();
// If the operand doesn't start with an '(', it must be an expression.
ExprResult Operand;
if (Tok.isNot(tok::l_paren)) {
Operand = ParseCastExpression(true);
} else {
// If it starts with a '(', we know that it is either a parenthesized
// type-name, or it is a unary-expression that starts with a compound
// literal, or starts with a primary-expression that is a parenthesized
// expression.
ParenParseOption ExprType = CastExpr;
TypeTy *CastTy;
SourceLocation LParenLoc = Tok.getLocation(), RParenLoc;
Operand = ParseParenExpression(ExprType, CastTy, RParenLoc);
// If ParseParenExpression parsed a '(typename)' sequence only, the this is
// sizeof/alignof a type. Otherwise, it is sizeof/alignof an expression.
if (ExprType == CastExpr) {
return Actions.ActOnSizeOfAlignOfTypeExpr(OpTok.getLocation(),
OpTok.is(tok::kw_sizeof),
LParenLoc, CastTy, RParenLoc);
}
}
// If we get here, the operand to the sizeof/alignof was an expresion.
if (!Operand.isInvalid)
Operand = Actions.ActOnUnaryOp(OpTok.getLocation(), OpTok.getKind(),
Operand.Val);
return Operand;
}
/// ParseBuiltinPrimaryExpression
///
/// primary-expression: [C99 6.5.1]
/// [GNU] '__builtin_va_arg' '(' assignment-expression ',' type-name ')'
/// [GNU] '__builtin_offsetof' '(' type-name ',' offsetof-member-designator')'
/// [GNU] '__builtin_choose_expr' '(' assign-expr ',' assign-expr ','
/// assign-expr ')'
/// [GNU] '__builtin_types_compatible_p' '(' type-name ',' type-name ')'
///
/// [GNU] offsetof-member-designator:
/// [GNU] identifier
/// [GNU] offsetof-member-designator '.' identifier
/// [GNU] offsetof-member-designator '[' expression ']'
///
Parser::ExprResult Parser::ParseBuiltinPrimaryExpression() {
ExprResult Res(false);
const IdentifierInfo *BuiltinII = Tok.getIdentifierInfo();
tok::TokenKind T = Tok.getKind();
SourceLocation StartLoc = ConsumeToken(); // Eat the builtin identifier.
// All of these start with an open paren.
if (Tok.isNot(tok::l_paren)) {
Diag(Tok, diag::err_expected_lparen_after, BuiltinII->getName());
return ExprResult(true);
}
SourceLocation LParenLoc = ConsumeParen();
// TODO: Build AST.
switch (T) {
default: assert(0 && "Not a builtin primary expression!");
case tok::kw___builtin_va_arg:
Res = ParseAssignmentExpression();
if (Res.isInvalid) {
SkipUntil(tok::r_paren);
return Res;
}
if (ExpectAndConsume(tok::comma, diag::err_expected_comma, "",tok::r_paren))
return ExprResult(true);
ParseTypeName();
MatchRHSPunctuation(tok::r_paren, LParenLoc);
break;
case tok::kw___builtin_offsetof: {
SourceLocation TypeLoc = Tok.getLocation();
TypeTy *Ty = ParseTypeName();
if (ExpectAndConsume(tok::comma, diag::err_expected_comma, "",tok::r_paren))
return ExprResult(true);
// We must have at least one identifier here.
if (Tok.isNot(tok::identifier)) {
Diag(Tok, diag::err_expected_ident);
SkipUntil(tok::r_paren);
return true;
}
// Keep track of the various subcomponents we see.
llvm::SmallVector<Action::OffsetOfComponent, 4> Comps;
Comps.push_back(Action::OffsetOfComponent());
Comps.back().isBrackets = false;
Comps.back().U.IdentInfo = Tok.getIdentifierInfo();
Comps.back().LocStart = Comps.back().LocEnd = ConsumeToken();
while (1) {
if (Tok.is(tok::period)) {
// offsetof-member-designator: offsetof-member-designator '.' identifier
Comps.push_back(Action::OffsetOfComponent());
Comps.back().isBrackets = false;
Comps.back().LocStart = ConsumeToken();
if (Tok.isNot(tok::identifier)) {
Diag(Tok, diag::err_expected_ident);
SkipUntil(tok::r_paren);
return true;
}
Comps.back().U.IdentInfo = Tok.getIdentifierInfo();
Comps.back().LocEnd = ConsumeToken();
} else if (Tok.is(tok::l_square)) {
// offsetof-member-designator: offsetof-member-design '[' expression ']'
Comps.push_back(Action::OffsetOfComponent());
Comps.back().isBrackets = true;
Comps.back().LocStart = ConsumeBracket();
Res = ParseExpression();
if (Res.isInvalid) {
SkipUntil(tok::r_paren);
return Res;
}
Comps.back().U.E = Res.Val;
Comps.back().LocEnd =
MatchRHSPunctuation(tok::r_square, Comps.back().LocStart);
} else if (Tok.is(tok::r_paren)) {
Res = Actions.ActOnBuiltinOffsetOf(StartLoc, TypeLoc, Ty, &Comps[0],
Comps.size(), ConsumeParen());
break;
} else {
// Error occurred.
return ExprResult(true);
}
}
break;
}
case tok::kw___builtin_choose_expr: {
ExprResult Cond = ParseAssignmentExpression();
if (Cond.isInvalid) {
SkipUntil(tok::r_paren);
return Cond;
}
if (ExpectAndConsume(tok::comma, diag::err_expected_comma, "",tok::r_paren))
return ExprResult(true);
ExprResult Expr1 = ParseAssignmentExpression();
if (Expr1.isInvalid) {
SkipUntil(tok::r_paren);
return Expr1;
}
if (ExpectAndConsume(tok::comma, diag::err_expected_comma, "",tok::r_paren))
return ExprResult(true);
ExprResult Expr2 = ParseAssignmentExpression();
if (Expr2.isInvalid) {
SkipUntil(tok::r_paren);
return Expr2;
}
if (Tok.isNot(tok::r_paren)) {
Diag(Tok, diag::err_expected_rparen);
return ExprResult(true);
}
Res = Actions.ActOnChooseExpr(StartLoc, Cond.Val, Expr1.Val, Expr2.Val,
ConsumeParen());
break;
}
case tok::kw___builtin_types_compatible_p:
TypeTy *Ty1 = ParseTypeName();
if (ExpectAndConsume(tok::comma, diag::err_expected_comma, "",tok::r_paren))
return ExprResult(true);
TypeTy *Ty2 = ParseTypeName();
if (Tok.isNot(tok::r_paren)) {
Diag(Tok, diag::err_expected_rparen);
return ExprResult(true);
}
Res = Actions.ActOnTypesCompatibleExpr(StartLoc, Ty1, Ty2, ConsumeParen());
break;
}
// These can be followed by postfix-expr pieces because they are
// primary-expressions.
return ParsePostfixExpressionSuffix(Res);
}
/// ParseParenExpression - This parses the unit that starts with a '(' token,
/// based on what is allowed by ExprType. The actual thing parsed is returned
/// in ExprType.
///
/// primary-expression: [C99 6.5.1]
/// '(' expression ')'
/// [GNU] '(' compound-statement ')' (if !ParenExprOnly)
/// postfix-expression: [C99 6.5.2]
/// '(' type-name ')' '{' initializer-list '}'
/// '(' type-name ')' '{' initializer-list ',' '}'
/// cast-expression: [C99 6.5.4]
/// '(' type-name ')' cast-expression
///
Parser::ExprResult Parser::ParseParenExpression(ParenParseOption &ExprType,
TypeTy *&CastTy,
SourceLocation &RParenLoc) {
assert(Tok.is(tok::l_paren) && "Not a paren expr!");
SourceLocation OpenLoc = ConsumeParen();
ExprResult Result(true);
CastTy = 0;
if (ExprType >= CompoundStmt && Tok.is(tok::l_brace)) {
Diag(Tok, diag::ext_gnu_statement_expr);
Parser::StmtResult Stmt = ParseCompoundStatement(true);
ExprType = CompoundStmt;
// If the substmt parsed correctly, build the AST node.
if (!Stmt.isInvalid && Tok.is(tok::r_paren))
Result = Actions.ActOnStmtExpr(OpenLoc, Stmt.Val, Tok.getLocation());
} else if (ExprType >= CompoundLiteral && isTypeSpecifierQualifier()) {
// Otherwise, this is a compound literal expression or cast expression.
TypeTy *Ty = ParseTypeName();
// Match the ')'.
if (Tok.is(tok::r_paren))
RParenLoc = ConsumeParen();
else
MatchRHSPunctuation(tok::r_paren, OpenLoc);
if (Tok.is(tok::l_brace)) {
if (!getLang().C99) // Compound literals don't exist in C90.
Diag(OpenLoc, diag::ext_c99_compound_literal);
Result = ParseInitializer();
ExprType = CompoundLiteral;
if (!Result.isInvalid)
return Actions.ActOnCompoundLiteral(OpenLoc, Ty, RParenLoc, Result.Val);
} else if (ExprType == CastExpr) {
// Note that this doesn't parse the subsequence cast-expression, it just
// returns the parsed type to the callee.
ExprType = CastExpr;
CastTy = Ty;
return ExprResult(false);
} else {
Diag(Tok, diag::err_expected_lbrace_in_compound_literal);
return ExprResult(true);
}
return Result;
} else {
Result = ParseExpression();
ExprType = SimpleExpr;
if (!Result.isInvalid && Tok.is(tok::r_paren))
Result = Actions.ActOnParenExpr(OpenLoc, Tok.getLocation(), Result.Val);
}
// Match the ')'.
if (Result.isInvalid)
SkipUntil(tok::r_paren);
else {
if (Tok.is(tok::r_paren))
RParenLoc = ConsumeParen();
else
MatchRHSPunctuation(tok::r_paren, OpenLoc);
}
return Result;
}
/// ParseStringLiteralExpression - This handles the various token types that
/// form string literals, and also handles string concatenation [C99 5.1.1.2,
/// translation phase #6].
///
/// primary-expression: [C99 6.5.1]
/// string-literal
Parser::ExprResult Parser::ParseStringLiteralExpression() {
assert(isTokenStringLiteral() && "Not a string literal!");
// String concat. Note that keywords like __func__ and __FUNCTION__ are not
// considered to be strings for concatenation purposes.
llvm::SmallVector<Token, 4> StringToks;
do {
StringToks.push_back(Tok);
ConsumeStringToken();
} while (isTokenStringLiteral());
// Pass the set of string tokens, ready for concatenation, to the actions.
return Actions.ActOnStringLiteral(&StringToks[0], StringToks.size());
}