llvm/clang/lib/Parse/ParseStmt.cpp

//===--- ParseStmt.cpp - Statement and Block Parser -----------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file implements the Statement and Block portions of the Parser
// interface.
//
//===----------------------------------------------------------------------===//

#include "clang/AST/PrettyDeclStackTrace.h"
#include "clang/Basic/Attributes.h"
#include "clang/Basic/PrettyStackTrace.h"
#include "clang/Basic/TargetInfo.h"
#include "clang/Basic/TokenKinds.h"
#include "clang/Parse/LoopHint.h"
#include "clang/Parse/Parser.h"
#include "clang/Parse/RAIIObjectsForParser.h"
#include "clang/Sema/DeclSpec.h"
#include "clang/Sema/EnterExpressionEvaluationContext.h"
#include "clang/Sema/Scope.h"
#include "clang/Sema/SemaCodeCompletion.h"
#include "clang/Sema/SemaObjC.h"
#include "clang/Sema/SemaOpenACC.h"
#include "clang/Sema/SemaOpenMP.h"
#include "clang/Sema/TypoCorrection.h"
#include "llvm/ADT/STLExtras.h"
#include <optional>

usingnamespaceclang;

//===----------------------------------------------------------------------===//
// C99 6.8: Statements and Blocks.
//===----------------------------------------------------------------------===//

/// Parse a standalone statement (for instance, as the body of an 'if',
/// 'while', or 'for').
StmtResult Parser::ParseStatement(SourceLocation *TrailingElseLoc,
                                  ParsedStmtContext StmtCtx) { … }

/// 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
/// [MS]    seh-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' ';'
///
StmtResult
Parser::ParseStatementOrDeclaration(StmtVector &Stmts,
                                    ParsedStmtContext StmtCtx,
                                    SourceLocation *TrailingElseLoc) { … }

namespace {
class StatementFilterCCC final : public CorrectionCandidateCallback { … };
}

StmtResult Parser::ParseStatementOrDeclarationAfterAttributes(
    StmtVector &Stmts, ParsedStmtContext StmtCtx,
    SourceLocation *TrailingElseLoc, ParsedAttributes &CXX11Attrs,
    ParsedAttributes &GNUAttrs) { … }

/// Parse an expression statement.
StmtResult Parser::ParseExprStatement(ParsedStmtContext StmtCtx) { … }

/// ParseSEHTryBlockCommon
///
/// seh-try-block:
///   '__try' compound-statement seh-handler
///
/// seh-handler:
///   seh-except-block
///   seh-finally-block
///
StmtResult Parser::ParseSEHTryBlock() { … }

/// ParseSEHExceptBlock - Handle __except
///
/// seh-except-block:
///   '__except' '(' seh-filter-expression ')' compound-statement
///
StmtResult Parser::ParseSEHExceptBlock(SourceLocation ExceptLoc) { … }

/// ParseSEHFinallyBlock - Handle __finally
///
/// seh-finally-block:
///   '__finally' compound-statement
///
StmtResult Parser::ParseSEHFinallyBlock(SourceLocation FinallyLoc) { … }

/// Handle __leave
///
/// seh-leave-statement:
///   '__leave' ';'
///
StmtResult Parser::ParseSEHLeaveStatement() { … }

static void DiagnoseLabelFollowedByDecl(Parser &P, const Stmt *SubStmt) { … }

/// ParseLabeledStatement - We have an identifier and a ':' after it.
///
///       label:
///         identifier ':'
/// [GNU]   identifier ':' attributes[opt]
///
///       labeled-statement:
///         label statement
///
StmtResult Parser::ParseLabeledStatement(ParsedAttributes &Attrs,
                                         ParsedStmtContext StmtCtx) { … }

/// ParseCaseStatement
///       labeled-statement:
///         'case' constant-expression ':' statement
/// [GNU]   'case' constant-expression '...' constant-expression ':' statement
///
StmtResult Parser::ParseCaseStatement(ParsedStmtContext StmtCtx,
                                      bool MissingCase, ExprResult Expr) { … }

/// ParseDefaultStatement
///       labeled-statement:
///         'default' ':' statement
/// Note that this does not parse the 'statement' at the end.
///
StmtResult Parser::ParseDefaultStatement(ParsedStmtContext StmtCtx) { … }

StmtResult Parser::ParseCompoundStatement(bool isStmtExpr) { … }

/// 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
///
/// [GNU] label-declarations:
/// [GNU]   label-declaration
/// [GNU]   label-declarations label-declaration
///
/// [GNU] label-declaration:
/// [GNU]   '__label__' identifier-list ';'
///
StmtResult Parser::ParseCompoundStatement(bool isStmtExpr,
                                          unsigned ScopeFlags) { … }

/// Parse any pragmas at the start of the compound expression. We handle these
/// separately since some pragmas (FP_CONTRACT) must appear before any C
/// statement in the compound, but may be intermingled with other pragmas.
void Parser::ParseCompoundStatementLeadingPragmas() { … }

void Parser::DiagnoseLabelAtEndOfCompoundStatement() { … }

/// Consume any extra semi-colons resulting in null statements,
/// returning true if any tok::semi were consumed.
bool Parser::ConsumeNullStmt(StmtVector &Stmts) { … }

StmtResult Parser::handleExprStmt(ExprResult E, ParsedStmtContext StmtCtx) { … }

/// ParseCompoundStatementBody - Parse a sequence of statements optionally
/// followed by a label 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.
StmtResult Parser::ParseCompoundStatementBody(bool isStmtExpr) { … }

/// ParseParenExprOrCondition:
/// [C  ]     '(' expression ')'
/// [C++]     '(' condition ')'
/// [C++1z]   '(' init-statement[opt] condition ')'
///
/// 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.
/// Additionally, it will assign the location of the outer-most '(' and ')',
/// to LParenLoc and RParenLoc, respectively.
bool Parser::ParseParenExprOrCondition(StmtResult *InitStmt,
                                       Sema::ConditionResult &Cond,
                                       SourceLocation Loc,
                                       Sema::ConditionKind CK,
                                       SourceLocation &LParenLoc,
                                       SourceLocation &RParenLoc) { … }

namespace {

enum MisleadingStatementKind { … };

struct MisleadingIndentationChecker { … };

}

/// 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
/// [C++23] 'if' '!' [opt] consteval compound-statement
/// [C++23] 'if' '!' [opt] consteval compound-statement 'else' statement
///
StmtResult Parser::ParseIfStatement(SourceLocation *TrailingElseLoc) { … }

/// ParseSwitchStatement
///       switch-statement:
///         'switch' '(' expression ')' statement
/// [C++]   'switch' '(' condition ')' statement
StmtResult Parser::ParseSwitchStatement(SourceLocation *TrailingElseLoc) { … }

/// ParseWhileStatement
///       while-statement: [C99 6.8.5.1]
///         'while' '(' expression ')' statement
/// [C++]   'while' '(' condition ')' statement
StmtResult Parser::ParseWhileStatement(SourceLocation *TrailingElseLoc) { … }

/// ParseDoStatement
///       do-statement: [C99 6.8.5.2]
///         'do' statement 'while' '(' expression ')' ';'
/// Note: this lets the caller parse the end ';'.
StmtResult Parser::ParseDoStatement() { … }

bool Parser::isForRangeIdentifier() { … }

/// 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
/// [C++0x] 'for'
///             'co_await'[opt]    [Coroutines]
///             '(' for-range-declaration ':' for-range-initializer ')'
///             statement
/// [OBJC2] 'for' '(' declaration 'in' expr ')' statement
/// [OBJC2] 'for' '(' expr 'in' expr ')' statement
///
/// [C++] for-init-statement:
/// [C++]   expression-statement
/// [C++]   simple-declaration
/// [C++23] alias-declaration
///
/// [C++0x] for-range-declaration:
/// [C++0x]   attribute-specifier-seq[opt] type-specifier-seq declarator
/// [C++0x] for-range-initializer:
/// [C++0x]   expression
/// [C++0x]   braced-init-list            [TODO]
StmtResult Parser::ParseForStatement(SourceLocation *TrailingElseLoc) { … }

/// ParseGotoStatement
///       jump-statement:
///         'goto' identifier ';'
/// [GNU]   'goto' '*' expression ';'
///
/// Note: this lets the caller parse the end ';'.
///
StmtResult Parser::ParseGotoStatement() { … }

/// ParseContinueStatement
///       jump-statement:
///         'continue' ';'
///
/// Note: this lets the caller parse the end ';'.
///
StmtResult Parser::ParseContinueStatement() { … }

/// ParseBreakStatement
///       jump-statement:
///         'break' ';'
///
/// Note: this lets the caller parse the end ';'.
///
StmtResult Parser::ParseBreakStatement() { … }

/// ParseReturnStatement
///       jump-statement:
///         'return' expression[opt] ';'
///         'return' braced-init-list ';'
///         'co_return' expression[opt] ';'
///         'co_return' braced-init-list ';'
StmtResult Parser::ParseReturnStatement() { … }

StmtResult Parser::ParsePragmaLoopHint(StmtVector &Stmts,
                                       ParsedStmtContext StmtCtx,
                                       SourceLocation *TrailingElseLoc,
                                       ParsedAttributes &Attrs) { … }

Decl *Parser::ParseFunctionStatementBody(Decl *Decl, ParseScope &BodyScope) { … }

/// ParseFunctionTryBlock - Parse a C++ function-try-block.
///
///       function-try-block:
///         'try' ctor-initializer[opt] compound-statement handler-seq
///
Decl *Parser::ParseFunctionTryBlock(Decl *Decl, ParseScope &BodyScope) { … }

bool Parser::trySkippingFunctionBody() { … }

/// ParseCXXTryBlock - Parse a C++ try-block.
///
///       try-block:
///         'try' compound-statement handler-seq
///
StmtResult Parser::ParseCXXTryBlock() { … }

/// ParseCXXTryBlockCommon - Parse the common part of try-block and
/// function-try-block.
///
///       try-block:
///         'try' compound-statement handler-seq
///
///       function-try-block:
///         'try' ctor-initializer[opt] compound-statement handler-seq
///
///       handler-seq:
///         handler handler-seq[opt]
///
///       [Borland] try-block:
///         'try' compound-statement seh-except-block
///         'try' compound-statement seh-finally-block
///
StmtResult Parser::ParseCXXTryBlockCommon(SourceLocation TryLoc, bool FnTry) { … }

/// ParseCXXCatchBlock - Parse a C++ catch block, called handler in the standard
///
///   handler:
///     'catch' '(' exception-declaration ')' compound-statement
///
///   exception-declaration:
///     attribute-specifier-seq[opt] type-specifier-seq declarator
///     attribute-specifier-seq[opt] type-specifier-seq abstract-declarator[opt]
///     '...'
///
StmtResult Parser::ParseCXXCatchBlock(bool FnCatch) { … }

void Parser::ParseMicrosoftIfExistsStatement(StmtVector &Stmts) { … }