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clang-1/lib/Parse/ParseStmt.cpp

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//===--- ParseStmt.cpp - Statement and Block Parser -----------------------===//
//
// 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 Statement and Block portions of the Parser
// interface.
//
//===----------------------------------------------------------------------===//
#include "clang/Parse/Parser.h"
#include "ExtensionRAIIObject.h"
#include "AstGuard.h"
#include "clang/Basic/Diagnostic.h"
#include "clang/Basic/SourceManager.h"
#include "clang/Parse/DeclSpec.h"
#include "clang/Parse/Scope.h"
using namespace clang;
//===----------------------------------------------------------------------===//
// C99 6.8: Statements and Blocks.
//===----------------------------------------------------------------------===//
/// ParseStatementOrDeclaration - Read 'statement' or 'declaration'.
/// StatementOrDeclaration:
/// statement
/// declaration
///
/// statement:
/// labeled-statement
/// compound-statement
/// expression-statement
/// selection-statement
/// iteration-statement
/// jump-statement
/// [C++] declaration-statement
/// [C++] try-block
/// [OBC] objc-throw-statement
/// [OBC] objc-try-catch-statement
/// [OBC] objc-synchronized-statement
/// [GNU] asm-statement
/// [OMP] openmp-construct [TODO]
///
/// labeled-statement:
/// identifier ':' statement
/// 'case' constant-expression ':' statement
/// 'default' ':' statement
///
/// selection-statement:
/// if-statement
/// switch-statement
///
/// iteration-statement:
/// while-statement
/// do-statement
/// for-statement
///
/// expression-statement:
/// expression[opt] ';'
///
/// jump-statement:
/// 'goto' identifier ';'
/// 'continue' ';'
/// 'break' ';'
/// 'return' expression[opt] ';'
/// [GNU] 'goto' '*' expression ';'
///
/// [OBC] objc-throw-statement:
/// [OBC] '@' 'throw' expression ';'
/// [OBC] '@' 'throw' ';'
///
Parser::OwningStmtResult
Parser::ParseStatementOrDeclaration(bool OnlyStatement) {
const char *SemiError = 0;
OwningStmtResult Res(Actions);
// Cases in this switch statement should fall through if the parser expects
// the token to end in a semicolon (in which case SemiError should be set),
// or they directly 'return;' if not.
tok::TokenKind Kind = Tok.getKind();
SourceLocation AtLoc;
switch (Kind) {
case tok::at: // May be a @try or @throw statement
{
AtLoc = ConsumeToken(); // consume @
return ParseObjCAtStatement(AtLoc);
}
case tok::identifier:
if (NextToken().is(tok::colon)) { // C99 6.8.1: labeled-statement
// identifier ':' statement
return ParseLabeledStatement();
}
// PASS THROUGH.
default:
if ((getLang().CPlusPlus || !OnlyStatement) && isDeclarationStatement()) {
SourceLocation DeclStart = Tok.getLocation();
DeclTy *Decl = ParseDeclaration(Declarator::BlockContext);
// FIXME: Pass in the right location for the end of the declstmt.
return Actions.ActOnDeclStmt(Decl, DeclStart, DeclStart);
} else if (Tok.is(tok::r_brace)) {
Diag(Tok, diag::err_expected_statement);
return StmtError();
} else {
// expression[opt] ';'
OwningExprResult Expr(ParseExpression());
if (Expr.isInvalid()) {
// If the expression is invalid, skip ahead to the next semicolon. Not
// doing this opens us up to the possibility of infinite loops if
// ParseExpression does not consume any tokens.
SkipUntil(tok::semi);
return StmtError();
}
// Otherwise, eat the semicolon.
ExpectAndConsume(tok::semi, diag::err_expected_semi_after_expr);
return Actions.ActOnExprStmt(move(Expr));
}
case tok::kw_case: // C99 6.8.1: labeled-statement
return ParseCaseStatement();
case tok::kw_default: // C99 6.8.1: labeled-statement
return ParseDefaultStatement();
case tok::l_brace: // C99 6.8.2: compound-statement
return ParseCompoundStatement();
case tok::semi: // C99 6.8.3p3: expression[opt] ';'
return Actions.ActOnNullStmt(ConsumeToken());
case tok::kw_if: // C99 6.8.4.1: if-statement
return ParseIfStatement();
case tok::kw_switch: // C99 6.8.4.2: switch-statement
return ParseSwitchStatement();
case tok::kw_while: // C99 6.8.5.1: while-statement
return ParseWhileStatement();
case tok::kw_do: // C99 6.8.5.2: do-statement
Res = ParseDoStatement();
SemiError = "do/while loop";
break;
case tok::kw_for: // C99 6.8.5.3: for-statement
return ParseForStatement();
case tok::kw_goto: // C99 6.8.6.1: goto-statement
Res = ParseGotoStatement();
SemiError = "goto statement";
break;
case tok::kw_continue: // C99 6.8.6.2: continue-statement
Res = ParseContinueStatement();
SemiError = "continue statement";
break;
case tok::kw_break: // C99 6.8.6.3: break-statement
Res = ParseBreakStatement();
SemiError = "break statement";
break;
case tok::kw_return: // C99 6.8.6.4: return-statement
Res = ParseReturnStatement();
SemiError = "return statement";
break;
case tok::kw_asm: {
bool msAsm = false;
Res = ParseAsmStatement(msAsm);
if (msAsm) return move(Res);
SemiError = "asm statement";
break;
}
case tok::kw_try: // C++ 15: try-block
return ParseCXXTryBlock();
}
// If we reached this code, the statement must end in a semicolon.
if (Tok.is(tok::semi)) {
ConsumeToken();
} else if (!Res.isInvalid()) {
Diag(Tok, diag::err_expected_semi_after) << SemiError;
// Skip until we see a } or ;, but don't eat it.
SkipUntil(tok::r_brace, true, true);
}
return move(Res);
}
/// ParseLabeledStatement - We have an identifier and a ':' after it.
///
/// labeled-statement:
/// identifier ':' statement
/// [GNU] identifier ':' attributes[opt] statement
///
Parser::OwningStmtResult Parser::ParseLabeledStatement() {
assert(Tok.is(tok::identifier) && Tok.getIdentifierInfo() &&
"Not an identifier!");
Token IdentTok = Tok; // Save the whole token.
ConsumeToken(); // eat the identifier.
assert(Tok.is(tok::colon) && "Not a label!");
// identifier ':' statement
SourceLocation ColonLoc = ConsumeToken();
// Read label attributes, if present.
DeclTy *AttrList = 0;
if (Tok.is(tok::kw___attribute))
// TODO: save these somewhere.
AttrList = ParseAttributes();
OwningStmtResult SubStmt(ParseStatement());
// Broken substmt shouldn't prevent the label from being added to the AST.
if (SubStmt.isInvalid())
SubStmt = Actions.ActOnNullStmt(ColonLoc);
return Actions.ActOnLabelStmt(IdentTok.getLocation(),
IdentTok.getIdentifierInfo(),
ColonLoc, move(SubStmt));
}
/// ParseCaseStatement
/// labeled-statement:
/// 'case' constant-expression ':' statement
/// [GNU] 'case' constant-expression '...' constant-expression ':' statement
///
/// Note that this does not parse the 'statement' at the end.
///
Parser::OwningStmtResult Parser::ParseCaseStatement() {
assert(Tok.is(tok::kw_case) && "Not a case stmt!");
SourceLocation CaseLoc = ConsumeToken(); // eat the 'case'.
OwningExprResult LHS(ParseConstantExpression());
if (LHS.isInvalid()) {
SkipUntil(tok::colon);
return StmtError();
}
// GNU case range extension.
SourceLocation DotDotDotLoc;
OwningExprResult RHS(Actions);
if (Tok.is(tok::ellipsis)) {
Diag(Tok, diag::ext_gnu_case_range);
DotDotDotLoc = ConsumeToken();
RHS = ParseConstantExpression();
if (RHS.isInvalid()) {
SkipUntil(tok::colon);
return StmtError();
}
}
if (Tok.isNot(tok::colon)) {
Diag(Tok, diag::err_expected_colon_after) << "'case'";
SkipUntil(tok::colon);
return StmtError();
}
SourceLocation ColonLoc = ConsumeToken();
// Diagnose the common error "switch (X) { case 4: }", which is not valid.
if (Tok.is(tok::r_brace)) {
Diag(Tok, diag::err_label_end_of_compound_statement);
return StmtError();
}
OwningStmtResult SubStmt(ParseStatement());
// Broken substmt shouldn't prevent the case from being added to the AST.
if (SubStmt.isInvalid())
SubStmt = Actions.ActOnNullStmt(ColonLoc);
return Actions.ActOnCaseStmt(CaseLoc, move(LHS), DotDotDotLoc,
move(RHS), ColonLoc, move(SubStmt));
}
/// ParseDefaultStatement
/// labeled-statement:
/// 'default' ':' statement
/// Note that this does not parse the 'statement' at the end.
///
Parser::OwningStmtResult Parser::ParseDefaultStatement() {
assert(Tok.is(tok::kw_default) && "Not a default stmt!");
SourceLocation DefaultLoc = ConsumeToken(); // eat the 'default'.
if (Tok.isNot(tok::colon)) {
Diag(Tok, diag::err_expected_colon_after) << "'default'";
SkipUntil(tok::colon);
return StmtError();
}
SourceLocation ColonLoc = ConsumeToken();
// Diagnose the common error "switch (X) {... default: }", which is not valid.
if (Tok.is(tok::r_brace)) {
Diag(Tok, diag::err_label_end_of_compound_statement);
return StmtError();
}
OwningStmtResult SubStmt(ParseStatement());
if (SubStmt.isInvalid())
return StmtError();
return Actions.ActOnDefaultStmt(DefaultLoc, ColonLoc,
move(SubStmt), CurScope);
}
/// ParseCompoundStatement - Parse a "{}" block.
///
/// compound-statement: [C99 6.8.2]
/// { block-item-list[opt] }
/// [GNU] { label-declarations block-item-list } [TODO]
///
/// block-item-list:
/// block-item
/// block-item-list block-item
///
/// block-item:
/// declaration
/// [GNU] '__extension__' declaration
/// statement
/// [OMP] openmp-directive [TODO]
///
/// [GNU] label-declarations:
/// [GNU] label-declaration
/// [GNU] label-declarations label-declaration
///
/// [GNU] label-declaration:
/// [GNU] '__label__' identifier-list ';'
///
/// [OMP] openmp-directive: [TODO]
/// [OMP] barrier-directive
/// [OMP] flush-directive
///
Parser::OwningStmtResult Parser::ParseCompoundStatement(bool isStmtExpr) {
assert(Tok.is(tok::l_brace) && "Not a compount stmt!");
// Enter a scope to hold everything within the compound stmt. Compound
// statements can always hold declarations.
ParseScope CompoundScope(this, Scope::DeclScope);
// Parse the statements in the body.
return ParseCompoundStatementBody(isStmtExpr);
}
/// ParseCompoundStatementBody - Parse a sequence of statements and invoke the
/// ActOnCompoundStmt action. This expects the '{' to be the current token, and
/// consume the '}' at the end of the block. It does not manipulate the scope
/// stack.
Parser::OwningStmtResult Parser::ParseCompoundStatementBody(bool isStmtExpr) {
SourceLocation LBraceLoc = ConsumeBrace(); // eat the '{'.
// TODO: "__label__ X, Y, Z;" is the GNU "Local Label" extension. These are
// only allowed at the start of a compound stmt regardless of the language.
typedef StmtVector StmtsTy;
StmtsTy Stmts(Actions);
while (Tok.isNot(tok::r_brace) && Tok.isNot(tok::eof)) {
OwningStmtResult R(Actions);
if (Tok.isNot(tok::kw___extension__)) {
R = ParseStatementOrDeclaration(false);
} else {
// __extension__ can start declarations and it can also be a unary
// operator for expressions. Consume multiple __extension__ markers here
// until we can determine which is which.
// FIXME: This loses extension expressions in the AST!
SourceLocation ExtLoc = ConsumeToken();
while (Tok.is(tok::kw___extension__))
ConsumeToken();
// __extension__ silences extension warnings in the subexpression.
ExtensionRAIIObject O(Diags); // Use RAII to do this.
// If this is the start of a declaration, parse it as such.
if (isDeclarationStatement()) {
// FIXME: Save the __extension__ on the decl as a node somehow.
SourceLocation DeclStart = Tok.getLocation();
DeclTy *Res = ParseDeclaration(Declarator::BlockContext);
// FIXME: Pass in the right location for the end of the declstmt.
R = Actions.ActOnDeclStmt(Res, DeclStart, DeclStart);
} else {
// Otherwise this was a unary __extension__ marker.
OwningExprResult Res(ParseExpressionWithLeadingExtension(ExtLoc));
if (Res.isInvalid()) {
SkipUntil(tok::semi);
continue;
}
// Eat the semicolon at the end of stmt and convert the expr into a
// statement.
ExpectAndConsume(tok::semi, diag::err_expected_semi_after_expr);
R = Actions.ActOnExprStmt(move(Res));
}
}
if (R.isUsable())
Stmts.push_back(R.release());
}
// We broke out of the while loop because we found a '}' or EOF.
if (Tok.isNot(tok::r_brace)) {
Diag(Tok, diag::err_expected_rbrace);
return StmtError();
}
SourceLocation RBraceLoc = ConsumeBrace();
return Actions.ActOnCompoundStmt(LBraceLoc, RBraceLoc, move_arg(Stmts),
isStmtExpr);
}
/// ParseParenExprOrCondition:
/// [C ] '(' expression ')'
/// [C++] '(' condition ')' [not allowed if OnlyAllowCondition=true]
///
/// This function parses and performs error recovery on the specified condition
/// or expression (depending on whether we're in C++ or C mode). This function
/// goes out of its way to recover well. It returns true if there was a parser
/// error (the right paren couldn't be found), which indicates that the caller
/// should try to recover harder. It returns false if the condition is
/// successfully parsed. Note that a successful parse can still have semantic
/// errors in the condition.
bool Parser::ParseParenExprOrCondition(OwningExprResult &CondExp,
bool OnlyAllowCondition) {
SourceLocation LParenLoc = ConsumeParen();
if (getLang().CPlusPlus)
CondExp = ParseCXXCondition();
else
CondExp = ParseExpression();
// If the parser was confused by the condition and we don't have a ')', try to
// recover by skipping ahead to a semi and bailing out. If condexp is
// semantically invalid but we have well formed code, keep going.
if (CondExp.isInvalid() && Tok.isNot(tok::r_paren)) {
SkipUntil(tok::semi);
// Skipping may have stopped if it found the containing ')'. If so, we can
// continue parsing the if statement.
if (Tok.isNot(tok::r_paren))
return true;
}
// Otherwise the condition is valid or the rparen is present.
MatchRHSPunctuation(tok::r_paren, LParenLoc);
return false;
}
/// ParseIfStatement
/// if-statement: [C99 6.8.4.1]
/// 'if' '(' expression ')' statement
/// 'if' '(' expression ')' statement 'else' statement
/// [C++] 'if' '(' condition ')' statement
/// [C++] 'if' '(' condition ')' statement 'else' statement
///
Parser::OwningStmtResult Parser::ParseIfStatement() {
assert(Tok.is(tok::kw_if) && "Not an if stmt!");
SourceLocation IfLoc = ConsumeToken(); // eat the 'if'.
if (Tok.isNot(tok::l_paren)) {
Diag(Tok, diag::err_expected_lparen_after) << "if";
SkipUntil(tok::semi);
return StmtError();
}
bool C99orCXX = getLang().C99 || getLang().CPlusPlus;
// C99 6.8.4p3 - In C99, the if statement is a block. This is not
// the case for C90.
//
// C++ 6.4p3:
// A name introduced by a declaration in a condition is in scope from its
// point of declaration until the end of the substatements controlled by the
// condition.
// C++ 3.3.2p4:
// Names declared in the for-init-statement, and in the condition of if,
// while, for, and switch statements are local to the if, while, for, or
// switch statement (including the controlled statement).
//
ParseScope IfScope(this, Scope::DeclScope | Scope::ControlScope, C99orCXX);
// Parse the condition.
OwningExprResult CondExp(Actions);
if (ParseParenExprOrCondition(CondExp))
return StmtError();
// C99 6.8.4p3 - In C99, the body of the if statement is a scope, even if
// there is no compound stmt. C90 does not have this clause. We only do this
// if the body isn't a compound statement to avoid push/pop in common cases.
//
// C++ 6.4p1:
// The substatement in a selection-statement (each substatement, in the else
// form of the if statement) implicitly defines a local scope.
//
// For C++ we create a scope for the condition and a new scope for
// substatements because:
// -When the 'then' scope exits, we want the condition declaration to still be
// active for the 'else' scope too.
// -Sema will detect name clashes by considering declarations of a
// 'ControlScope' as part of its direct subscope.
// -If we wanted the condition and substatement to be in the same scope, we
// would have to notify ParseStatement not to create a new scope. It's
// simpler to let it create a new scope.
//
ParseScope InnerScope(this, Scope::DeclScope,
C99orCXX && Tok.isNot(tok::l_brace));
// Read the 'then' stmt.
SourceLocation ThenStmtLoc = Tok.getLocation();
OwningStmtResult ThenStmt(ParseStatement());
// Pop the 'if' scope if needed.
InnerScope.Exit();
// If it has an else, parse it.
SourceLocation ElseLoc;
SourceLocation ElseStmtLoc;
OwningStmtResult ElseStmt(Actions);
if (Tok.is(tok::kw_else)) {
ElseLoc = ConsumeToken();
// C99 6.8.4p3 - In C99, the body of the if statement is a scope, even if
// there is no compound stmt. C90 does not have this clause. We only do
// this if the body isn't a compound statement to avoid push/pop in common
// cases.
//
// C++ 6.4p1:
// The substatement in a selection-statement (each substatement, in the else
// form of the if statement) implicitly defines a local scope.
//
ParseScope InnerScope(this, Scope::DeclScope,
C99orCXX && Tok.isNot(tok::l_brace));
bool WithinElse = CurScope->isWithinElse();
CurScope->setWithinElse(true);
ElseStmtLoc = Tok.getLocation();
ElseStmt = ParseStatement();
CurScope->setWithinElse(WithinElse);
// Pop the 'else' scope if needed.
InnerScope.Exit();
}
IfScope.Exit();
// If the condition was invalid, discard the if statement. We could recover
// better by replacing it with a valid expr, but don't do that yet.
if (CondExp.isInvalid())
return StmtError();
// If the then or else stmt is invalid and the other is valid (and present),
// make turn the invalid one into a null stmt to avoid dropping the other
// part. If both are invalid, return error.
if ((ThenStmt.isInvalid() && ElseStmt.isInvalid()) ||
(ThenStmt.isInvalid() && ElseStmt.get() == 0) ||
(ThenStmt.get() == 0 && ElseStmt.isInvalid())) {
// Both invalid, or one is invalid and other is non-present: return error.
return StmtError();
}
// Now if either are invalid, replace with a ';'.
if (ThenStmt.isInvalid())
ThenStmt = Actions.ActOnNullStmt(ThenStmtLoc);
if (ElseStmt.isInvalid())
ElseStmt = Actions.ActOnNullStmt(ElseStmtLoc);
return Actions.ActOnIfStmt(IfLoc, move(CondExp), move(ThenStmt),
ElseLoc, move(ElseStmt));
}
/// ParseSwitchStatement
/// switch-statement:
/// 'switch' '(' expression ')' statement
/// [C++] 'switch' '(' condition ')' statement
Parser::OwningStmtResult Parser::ParseSwitchStatement() {
assert(Tok.is(tok::kw_switch) && "Not a switch stmt!");
SourceLocation SwitchLoc = ConsumeToken(); // eat the 'switch'.
if (Tok.isNot(tok::l_paren)) {
Diag(Tok, diag::err_expected_lparen_after) << "switch";
SkipUntil(tok::semi);
return StmtError();
}
bool C99orCXX = getLang().C99 || getLang().CPlusPlus;
// C99 6.8.4p3 - In C99, the switch statement is a block. This is
// not the case for C90. Start the switch scope.
//
// C++ 6.4p3:
// A name introduced by a declaration in a condition is in scope from its
// point of declaration until the end of the substatements controlled by the
// condition.
// C++ 3.3.2p4:
// Names declared in the for-init-statement, and in the condition of if,
// while, for, and switch statements are local to the if, while, for, or
// switch statement (including the controlled statement).
//
unsigned ScopeFlags = Scope::BreakScope;
if (C99orCXX)
ScopeFlags |= Scope::DeclScope | Scope::ControlScope;
ParseScope SwitchScope(this, ScopeFlags);
// Parse the condition.
OwningExprResult Cond(Actions);
if (ParseParenExprOrCondition(Cond))
return StmtError();
OwningStmtResult Switch(Actions);
if (!Cond.isInvalid())
Switch = Actions.ActOnStartOfSwitchStmt(move(Cond));
// C99 6.8.4p3 - In C99, the body of the switch statement is a scope, even if
// there is no compound stmt. C90 does not have this clause. We only do this
// if the body isn't a compound statement to avoid push/pop in common cases.
//
// C++ 6.4p1:
// The substatement in a selection-statement (each substatement, in the else
// form of the if statement) implicitly defines a local scope.
//
// See comments in ParseIfStatement for why we create a scope for the
// condition and a new scope for substatement in C++.
//
ParseScope InnerScope(this, Scope::DeclScope,
C99orCXX && Tok.isNot(tok::l_brace));
// Read the body statement.
OwningStmtResult Body(ParseStatement());
// Pop the body scope if needed.
InnerScope.Exit();
if (Body.isInvalid()) {
Body = Actions.ActOnNullStmt(Tok.getLocation());
// FIXME: Remove the case statement list from the Switch statement.
}
SwitchScope.Exit();
if (Cond.isInvalid())
return StmtError();
return Actions.ActOnFinishSwitchStmt(SwitchLoc, move(Switch), move(Body));
}
/// ParseWhileStatement
/// while-statement: [C99 6.8.5.1]
/// 'while' '(' expression ')' statement
/// [C++] 'while' '(' condition ')' statement
Parser::OwningStmtResult Parser::ParseWhileStatement() {
assert(Tok.is(tok::kw_while) && "Not a while stmt!");
SourceLocation WhileLoc = Tok.getLocation();
ConsumeToken(); // eat the 'while'.
if (Tok.isNot(tok::l_paren)) {
Diag(Tok, diag::err_expected_lparen_after) << "while";
SkipUntil(tok::semi);
return StmtError();
}
bool C99orCXX = getLang().C99 || getLang().CPlusPlus;
// C99 6.8.5p5 - In C99, the while statement is a block. This is not
// the case for C90. Start the loop scope.
//
// C++ 6.4p3:
// A name introduced by a declaration in a condition is in scope from its
// point of declaration until the end of the substatements controlled by the
// condition.
// C++ 3.3.2p4:
// Names declared in the for-init-statement, and in the condition of if,
// while, for, and switch statements are local to the if, while, for, or
// switch statement (including the controlled statement).
//
unsigned ScopeFlags;
if (C99orCXX)
ScopeFlags = Scope::BreakScope | Scope::ContinueScope |
Scope::DeclScope | Scope::ControlScope;
else
ScopeFlags = Scope::BreakScope | Scope::ContinueScope;
ParseScope WhileScope(this, ScopeFlags);
// Parse the condition.
OwningExprResult Cond(Actions);
if (ParseParenExprOrCondition(Cond))
return StmtError();
// C99 6.8.5p5 - In C99, the body of the if statement is a scope, even if
// there is no compound stmt. C90 does not have this clause. We only do this
// if the body isn't a compound statement to avoid push/pop in common cases.
//
// C++ 6.5p2:
// The substatement in an iteration-statement implicitly defines a local scope
// which is entered and exited each time through the loop.
//
// See comments in ParseIfStatement for why we create a scope for the
// condition and a new scope for substatement in C++.
//
ParseScope InnerScope(this, Scope::DeclScope,
C99orCXX && Tok.isNot(tok::l_brace));
// Read the body statement.
OwningStmtResult Body(ParseStatement());
// Pop the body scope if needed.
InnerScope.Exit();
WhileScope.Exit();
if (Cond.isInvalid() || Body.isInvalid())
return StmtError();
return Actions.ActOnWhileStmt(WhileLoc, move(Cond), move(Body));
}
/// ParseDoStatement
/// do-statement: [C99 6.8.5.2]
/// 'do' statement 'while' '(' expression ')' ';'
/// Note: this lets the caller parse the end ';'.
Parser::OwningStmtResult Parser::ParseDoStatement() {
assert(Tok.is(tok::kw_do) && "Not a do stmt!");
SourceLocation DoLoc = ConsumeToken(); // eat the 'do'.
// C99 6.8.5p5 - In C99, the do statement is a block. This is not
// the case for C90. Start the loop scope.
unsigned ScopeFlags;
if (getLang().C99)
ScopeFlags = Scope::BreakScope | Scope::ContinueScope | Scope::DeclScope;
else
ScopeFlags = Scope::BreakScope | Scope::ContinueScope;
ParseScope DoScope(this, ScopeFlags);
// C99 6.8.5p5 - In C99, the body of the if statement is a scope, even if
// there is no compound stmt. C90 does not have this clause. We only do this
// if the body isn't a compound statement to avoid push/pop in common cases.
//
// C++ 6.5p2:
// The substatement in an iteration-statement implicitly defines a local scope
// which is entered and exited each time through the loop.
//
ParseScope InnerScope(this, Scope::DeclScope,
(getLang().C99 || getLang().CPlusPlus) &&
Tok.isNot(tok::l_brace));
// Read the body statement.
OwningStmtResult Body(ParseStatement());
// Pop the body scope if needed.
InnerScope.Exit();
if (Tok.isNot(tok::kw_while)) {
if (!Body.isInvalid()) {
Diag(Tok, diag::err_expected_while);
Diag(DoLoc, diag::note_matching) << "do";
SkipUntil(tok::semi, false, true);
}
return StmtError();
}
SourceLocation WhileLoc = ConsumeToken();
if (Tok.isNot(tok::l_paren)) {
Diag(Tok, diag::err_expected_lparen_after) << "do/while";
SkipUntil(tok::semi, false, true);
return StmtError();
}
// Parse the parenthesized condition.
OwningExprResult Cond(Actions);
ParseParenExprOrCondition(Cond, true);
DoScope.Exit();
if (Cond.isInvalid() || Body.isInvalid())
return StmtError();
return Actions.ActOnDoStmt(DoLoc, move(Body), WhileLoc, move(Cond));
}
/// ParseForStatement
/// for-statement: [C99 6.8.5.3]
/// 'for' '(' expr[opt] ';' expr[opt] ';' expr[opt] ')' statement
/// 'for' '(' declaration expr[opt] ';' expr[opt] ')' statement
/// [C++] 'for' '(' for-init-statement condition[opt] ';' expression[opt] ')'
/// [C++] statement
/// [OBJC2] 'for' '(' declaration 'in' expr ')' statement
/// [OBJC2] 'for' '(' expr 'in' expr ')' statement
///
/// [C++] for-init-statement:
/// [C++] expression-statement
/// [C++] simple-declaration
///
Parser::OwningStmtResult Parser::ParseForStatement() {
assert(Tok.is(tok::kw_for) && "Not a for stmt!");
SourceLocation ForLoc = ConsumeToken(); // eat the 'for'.
if (Tok.isNot(tok::l_paren)) {
Diag(Tok, diag::err_expected_lparen_after) << "for";
SkipUntil(tok::semi);
return StmtError();
}
bool C99orCXX = getLang().C99 || getLang().CPlusPlus;
// C99 6.8.5p5 - In C99, the for statement is a block. This is not
// the case for C90. Start the loop scope.
//
// C++ 6.4p3:
// A name introduced by a declaration in a condition is in scope from its
// point of declaration until the end of the substatements controlled by the
// condition.
// C++ 3.3.2p4:
// Names declared in the for-init-statement, and in the condition of if,
// while, for, and switch statements are local to the if, while, for, or
// switch statement (including the controlled statement).
// C++ 6.5.3p1:
// Names declared in the for-init-statement are in the same declarative-region
// as those declared in the condition.
//
unsigned ScopeFlags;
if (C99orCXX)
ScopeFlags = Scope::BreakScope | Scope::ContinueScope |
Scope::DeclScope | Scope::ControlScope;
else
ScopeFlags = Scope::BreakScope | Scope::ContinueScope;
ParseScope ForScope(this, ScopeFlags);
SourceLocation LParenLoc = ConsumeParen();
OwningExprResult Value(Actions);
bool ForEach = false;
OwningStmtResult FirstPart(Actions);
OwningExprResult SecondPart(Actions), ThirdPart(Actions);
// Parse the first part of the for specifier.
if (Tok.is(tok::semi)) { // for (;
// no first part, eat the ';'.
ConsumeToken();
} else if (isSimpleDeclaration()) { // for (int X = 4;
// Parse declaration, which eats the ';'.
if (!C99orCXX) // Use of C99-style for loops in C90 mode?
Diag(Tok, diag::ext_c99_variable_decl_in_for_loop);
SourceLocation DeclStart = Tok.getLocation();
DeclTy *aBlockVarDecl = ParseSimpleDeclaration(Declarator::ForContext);
// FIXME: Pass in the right location for the end of the declstmt.
FirstPart = Actions.ActOnDeclStmt(aBlockVarDecl, DeclStart,
DeclStart);
if ((ForEach = isTokIdentifier_in())) {
ConsumeToken(); // consume 'in'
SecondPart = ParseExpression();
}
} else {
Value = ParseExpression();
// Turn the expression into a stmt.
if (!Value.isInvalid())
FirstPart = Actions.ActOnExprStmt(move(Value));
if (Tok.is(tok::semi)) {
ConsumeToken();
}
else if ((ForEach = isTokIdentifier_in())) {
ConsumeToken(); // consume 'in'
SecondPart = ParseExpression();
}
else {
if (!Value.isInvalid()) Diag(Tok, diag::err_expected_semi_for);
SkipUntil(tok::semi);
}
}
if (!ForEach) {
assert(!SecondPart.get() && "Shouldn't have a second expression yet.");
// Parse the second part of the for specifier.
if (Tok.is(tok::semi)) { // for (...;;
// no second part.
} else {
SecondPart =getLang().CPlusPlus ? ParseCXXCondition() : ParseExpression();
}
if (Tok.is(tok::semi)) {
ConsumeToken();
} else {
if (!SecondPart.isInvalid()) Diag(Tok, diag::err_expected_semi_for);
SkipUntil(tok::semi);
}
// Parse the third part of the for specifier.
if (Tok.is(tok::r_paren)) { // for (...;...;)
// no third part.
} else {
ThirdPart = ParseExpression();
}
}
// Match the ')'.
SourceLocation RParenLoc = MatchRHSPunctuation(tok::r_paren, LParenLoc);
// C99 6.8.5p5 - In C99, the body of the if statement is a scope, even if
// there is no compound stmt. C90 does not have this clause. We only do this
// if the body isn't a compound statement to avoid push/pop in common cases.
//
// C++ 6.5p2:
// The substatement in an iteration-statement implicitly defines a local scope
// which is entered and exited each time through the loop.
//
// See comments in ParseIfStatement for why we create a scope for
// for-init-statement/condition and a new scope for substatement in C++.
//
ParseScope InnerScope(this, Scope::DeclScope,
C99orCXX && Tok.isNot(tok::l_brace));
// Read the body statement.
OwningStmtResult Body(ParseStatement());
// Pop the body scope if needed.
InnerScope.Exit();
// Leave the for-scope.
ForScope.Exit();
if (Body.isInvalid())
return StmtError();
if (!ForEach)
return Actions.ActOnForStmt(ForLoc, LParenLoc, move(FirstPart),
move(SecondPart), move(ThirdPart),
RParenLoc, move(Body));
else
return Actions.ActOnObjCForCollectionStmt(ForLoc, LParenLoc,
move(FirstPart),
move(SecondPart),
RParenLoc, move(Body));
}
/// ParseGotoStatement
/// jump-statement:
/// 'goto' identifier ';'
/// [GNU] 'goto' '*' expression ';'
///
/// Note: this lets the caller parse the end ';'.
///
Parser::OwningStmtResult Parser::ParseGotoStatement() {
assert(Tok.is(tok::kw_goto) && "Not a goto stmt!");
SourceLocation GotoLoc = ConsumeToken(); // eat the 'goto'.
OwningStmtResult Res(Actions);
if (Tok.is(tok::identifier)) {
Res = Actions.ActOnGotoStmt(GotoLoc, Tok.getLocation(),
Tok.getIdentifierInfo());
ConsumeToken();
} else if (Tok.is(tok::star) && !getLang().NoExtensions) {
// GNU indirect goto extension.
Diag(Tok, diag::ext_gnu_indirect_goto);
SourceLocation StarLoc = ConsumeToken();
OwningExprResult R(ParseExpression());
if (R.isInvalid()) { // Skip to the semicolon, but don't consume it.
SkipUntil(tok::semi, false, true);
return StmtError();
}
Res = Actions.ActOnIndirectGotoStmt(GotoLoc, StarLoc, move(R));
} else {
Diag(Tok, diag::err_expected_ident);
return StmtError();
}
return move(Res);
}
/// ParseContinueStatement
/// jump-statement:
/// 'continue' ';'
///
/// Note: this lets the caller parse the end ';'.
///
Parser::OwningStmtResult Parser::ParseContinueStatement() {
SourceLocation ContinueLoc = ConsumeToken(); // eat the 'continue'.
return Actions.ActOnContinueStmt(ContinueLoc, CurScope);
}
/// ParseBreakStatement
/// jump-statement:
/// 'break' ';'
///
/// Note: this lets the caller parse the end ';'.
///
Parser::OwningStmtResult Parser::ParseBreakStatement() {
SourceLocation BreakLoc = ConsumeToken(); // eat the 'break'.
return Actions.ActOnBreakStmt(BreakLoc, CurScope);
}
/// ParseReturnStatement
/// jump-statement:
/// 'return' expression[opt] ';'
Parser::OwningStmtResult Parser::ParseReturnStatement() {
assert(Tok.is(tok::kw_return) && "Not a return stmt!");
SourceLocation ReturnLoc = ConsumeToken(); // eat the 'return'.
OwningExprResult R(Actions);
if (Tok.isNot(tok::semi)) {
R = ParseExpression();
if (R.isInvalid()) { // Skip to the semicolon, but don't consume it.
SkipUntil(tok::semi, false, true);
return StmtError();
}
}
return Actions.ActOnReturnStmt(ReturnLoc, move(R));
}
/// FuzzyParseMicrosoftAsmStatement. When -fms-extensions is enabled, this
/// routine is called to skip/ignore tokens that comprise the MS asm statement.
Parser::OwningStmtResult Parser::FuzzyParseMicrosoftAsmStatement() {
if (Tok.is(tok::l_brace)) {
unsigned short savedBraceCount = BraceCount;
do {
ConsumeAnyToken();
} while (BraceCount > savedBraceCount && Tok.isNot(tok::eof));
} else {
// From the MS website: If used without braces, the __asm keyword means
// that the rest of the line is an assembly-language statement.
SourceManager &SrcMgr = PP.getSourceManager();
SourceLocation TokLoc = Tok.getLocation();
unsigned LineNo = SrcMgr.getInstantiationLineNumber(TokLoc);
do {
ConsumeAnyToken();
TokLoc = Tok.getLocation();
} while ((SrcMgr.getInstantiationLineNumber(TokLoc) == LineNo) &&
Tok.isNot(tok::r_brace) && Tok.isNot(tok::semi) &&
Tok.isNot(tok::eof));
}
return Actions.ActOnNullStmt(Tok.getLocation());
}
/// ParseAsmStatement - Parse a GNU extended asm statement.
/// asm-statement:
/// gnu-asm-statement
/// ms-asm-statement
///
/// [GNU] gnu-asm-statement:
/// 'asm' type-qualifier[opt] '(' asm-argument ')' ';'
///
/// [GNU] asm-argument:
/// asm-string-literal
/// asm-string-literal ':' asm-operands[opt]
/// asm-string-literal ':' asm-operands[opt] ':' asm-operands[opt]
/// asm-string-literal ':' asm-operands[opt] ':' asm-operands[opt]
/// ':' asm-clobbers
///
/// [GNU] asm-clobbers:
/// asm-string-literal
/// asm-clobbers ',' asm-string-literal
///
/// [MS] ms-asm-statement:
/// '__asm' assembly-instruction ';'[opt]
/// '__asm' '{' assembly-instruction-list '}' ';'[opt]
///
/// [MS] assembly-instruction-list:
/// assembly-instruction ';'[opt]
/// assembly-instruction-list ';' assembly-instruction ';'[opt]
///
Parser::OwningStmtResult Parser::ParseAsmStatement(bool &msAsm) {
assert(Tok.is(tok::kw_asm) && "Not an asm stmt");
SourceLocation AsmLoc = ConsumeToken();
if (getLang().Microsoft && Tok.isNot(tok::l_paren) && !isTypeQualifier()) {
msAsm = true;
return FuzzyParseMicrosoftAsmStatement();
}
DeclSpec DS;
SourceLocation Loc = Tok.getLocation();
ParseTypeQualifierListOpt(DS);
// GNU asms accept, but warn, about type-qualifiers other than volatile.
if (DS.getTypeQualifiers() & DeclSpec::TQ_const)
Diag(Loc, diag::w_asm_qualifier_ignored) << "const";
if (DS.getTypeQualifiers() & DeclSpec::TQ_restrict)
Diag(Loc, diag::w_asm_qualifier_ignored) << "restrict";
// Remember if this was a volatile asm.
bool isVolatile = DS.getTypeQualifiers() & DeclSpec::TQ_volatile;
bool isSimple = false;
if (Tok.isNot(tok::l_paren)) {
Diag(Tok, diag::err_expected_lparen_after) << "asm";
SkipUntil(tok::r_paren);
return StmtError();
}
Loc = ConsumeParen();
OwningExprResult AsmString(ParseAsmStringLiteral());
if (AsmString.isInvalid())
return StmtError();
llvm::SmallVector<std::string, 4> Names;
ExprVector Constraints(Actions);
ExprVector Exprs(Actions);
ExprVector Clobbers(Actions);
unsigned NumInputs = 0, NumOutputs = 0;
SourceLocation RParenLoc;
if (Tok.is(tok::r_paren)) {
// We have a simple asm expression
isSimple = true;
RParenLoc = ConsumeParen();
} else {
// Parse Outputs, if present.
if (ParseAsmOperandsOpt(Names, Constraints, Exprs))
return StmtError();
NumOutputs = Names.size();
// Parse Inputs, if present.
if (ParseAsmOperandsOpt(Names, Constraints, Exprs))
return StmtError();
assert(Names.size() == Constraints.size() &&
Constraints.size() == Exprs.size()
&& "Input operand size mismatch!");
NumInputs = Names.size() - NumOutputs;
// Parse the clobbers, if present.
if (Tok.is(tok::colon)) {
ConsumeToken();
// Parse the asm-string list for clobbers.
while (1) {
OwningExprResult Clobber(ParseAsmStringLiteral());
if (Clobber.isInvalid())
break;
Clobbers.push_back(Clobber.release());
if (Tok.isNot(tok::comma)) break;
ConsumeToken();
}
}
RParenLoc = MatchRHSPunctuation(tok::r_paren, Loc);
}
return Actions.ActOnAsmStmt(AsmLoc, isSimple, isVolatile,
NumOutputs, NumInputs, &Names[0],
move_arg(Constraints), move_arg(Exprs),
move(AsmString), move_arg(Clobbers),
RParenLoc);
}
/// ParseAsmOperands - Parse the asm-operands production as used by
/// asm-statement. We also parse a leading ':' token. If the leading colon is
/// not present, we do not parse anything.
///
/// [GNU] asm-operands:
/// asm-operand
/// asm-operands ',' asm-operand
///
/// [GNU] asm-operand:
/// asm-string-literal '(' expression ')'
/// '[' identifier ']' asm-string-literal '(' expression ')'
///
bool Parser::ParseAsmOperandsOpt(llvm::SmallVectorImpl<std::string> &Names,
llvm::SmallVectorImpl<ExprTy*> &Constraints,
llvm::SmallVectorImpl<ExprTy*> &Exprs) {
// Only do anything if this operand is present.
if (Tok.isNot(tok::colon)) return false;
ConsumeToken();
// 'asm-operands' isn't present?
if (!isTokenStringLiteral() && Tok.isNot(tok::l_square))
return false;
while (1) {
// Read the [id] if present.
if (Tok.is(tok::l_square)) {
SourceLocation Loc = ConsumeBracket();
if (Tok.isNot(tok::identifier)) {
Diag(Tok, diag::err_expected_ident);
SkipUntil(tok::r_paren);
return true;
}
IdentifierInfo *II = Tok.getIdentifierInfo();
ConsumeToken();
Names.push_back(std::string(II->getName(), II->getLength()));
MatchRHSPunctuation(tok::r_square, Loc);
} else
Names.push_back(std::string());
OwningExprResult Constraint(ParseAsmStringLiteral());
if (Constraint.isInvalid()) {
SkipUntil(tok::r_paren);
return true;
}
Constraints.push_back(Constraint.release());
if (Tok.isNot(tok::l_paren)) {
Diag(Tok, diag::err_expected_lparen_after) << "asm operand";
SkipUntil(tok::r_paren);
return true;
}
// Read the parenthesized expression.
OwningExprResult Res(ParseSimpleParenExpression());
if (Res.isInvalid()) {
SkipUntil(tok::r_paren);
return true;
}
Exprs.push_back(Res.release());
// Eat the comma and continue parsing if it exists.
if (Tok.isNot(tok::comma)) return false;
ConsumeToken();
}
return true;
}
Parser::DeclTy *Parser::ParseFunctionStatementBody(DeclTy *Decl,
SourceLocation L, SourceLocation R) {
// Do not enter a scope for the brace, as the arguments are in the same scope
// (the function body) as the body itself. Instead, just read the statement
// list and put it into a CompoundStmt for safe keeping.
OwningStmtResult FnBody(ParseCompoundStatementBody());
// If the function body could not be parsed, make a bogus compoundstmt.
if (FnBody.isInvalid())
FnBody = Actions.ActOnCompoundStmt(L, R, MultiStmtArg(Actions), false);
return Actions.ActOnFinishFunctionBody(Decl, move(FnBody));
}
/// ParseCXXTryBlock - Parse a C++ try-block.
///
/// try-block:
/// 'try' compound-statement handler-seq
///
/// handler-seq:
/// handler handler-seq[opt]
///
Parser::OwningStmtResult Parser::ParseCXXTryBlock() {
assert(Tok.is(tok::kw_try) && "Expected 'try'");
SourceLocation TryLoc = ConsumeToken();
if (Tok.isNot(tok::l_brace))
return StmtError(Diag(Tok, diag::err_expected_lbrace));
OwningStmtResult TryBlock(ParseCompoundStatement());
if (TryBlock.isInvalid())
return move(TryBlock);
StmtVector Handlers(Actions);
if (Tok.isNot(tok::kw_catch))
return StmtError(Diag(Tok, diag::err_expected_catch));
while (Tok.is(tok::kw_catch)) {
OwningStmtResult Handler(ParseCXXCatchBlock());
if (!Handler.isInvalid())
Handlers.push_back(Handler.release());
}
// Don't bother creating the full statement if we don't have any usable
// handlers.
if (Handlers.empty())
return StmtError();
return Actions.ActOnCXXTryBlock(TryLoc, move(TryBlock), move_arg(Handlers));
}
/// ParseCXXCatchBlock - Parse a C++ catch block, called handler in the standard
///
/// handler:
/// 'catch' '(' exception-declaration ')' compound-statement
///
/// exception-declaration:
/// type-specifier-seq declarator
/// type-specifier-seq abstract-declarator
/// type-specifier-seq
/// '...'
///
Parser::OwningStmtResult Parser::ParseCXXCatchBlock() {
assert(Tok.is(tok::kw_catch) && "Expected 'catch'");
SourceLocation CatchLoc = ConsumeToken();
SourceLocation LParenLoc = Tok.getLocation();
if (ExpectAndConsume(tok::l_paren, diag::err_expected_lparen))
return StmtError();
// C++ 3.3.2p3:
// The name in a catch exception-declaration is local to the handler and
// shall not be redeclared in the outermost block of the handler.
ParseScope CatchScope(this, Scope::DeclScope | Scope::ControlScope);
// exception-declaration is equivalent to '...' or a parameter-declaration
// without default arguments.
DeclTy *ExceptionDecl = 0;
if (Tok.isNot(tok::ellipsis)) {
DeclSpec DS;
if (ParseCXXTypeSpecifierSeq(DS))
return StmtError();
Declarator ExDecl(DS, Declarator::CXXCatchContext);
ParseDeclarator(ExDecl);
ExceptionDecl = Actions.ActOnExceptionDeclarator(CurScope, ExDecl);
} else
ConsumeToken();
if (MatchRHSPunctuation(tok::r_paren, LParenLoc).isInvalid())
return StmtError();
if (Tok.isNot(tok::l_brace))
return StmtError(Diag(Tok, diag::err_expected_lbrace));
OwningStmtResult Block(ParseCompoundStatement());
if (Block.isInvalid())
return move(Block);
return Actions.ActOnCXXCatchBlock(CatchLoc, ExceptionDecl, move(Block));
}
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