clang/Parse/ParseStmt.cpp

//===--- Statement.cpp - Statement and Block Parser -----------------------===//
//
//                     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 Statement and Block portions of the Parser
// interface.
//
//===----------------------------------------------------------------------===//

#include "clang/Parse/Parser.h"
#include "clang/Basic/Diagnostic.h"
using namespace llvm;
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
/// [OBC]   objc-throw-statement         [TODO]
/// [OBC]   objc-try-catch-statement     [TODO]
/// [OBC]   objc-synchronized-statement  [TODO]
/// [GNU]   asm-statement                [TODO]
/// [OMP]   openmp-construct             [TODO]
///
///       labeled-statement:
///         identifier ':' statement
///         'case' constant-expression ':' statement
///         'default' ':' statement
///
///       expression-statement:
///         expression[opt] ';'
///
///       selection-statement:
///         if-statement
///         switch-statement
///
///       iteration-statement:
///         while-statement
///         do-statement
///         for-statement
///
///       jump-statement:
///         'goto' identifier ';'
///         'continue' ';'
///         'break' ';'
///         'return' expression[opt] ';'
/// [GNU]   'goto' '*' expression ';'     [TODO]
///
/// [OBC] objc-throw-statement:           [TODO]
/// [OBC]   '@' 'throw' expression ';'    [TODO]
/// [OBC]   '@' 'throw' ';'               [TODO]
/// 
void Parser::ParseStatementOrDeclaration(bool OnlyStatement) {
  switch (Tok.getKind()) {
  default:
    Diag(Tok, diag::err_expected_statement_declaration);
    SkipUntil(tok::semi);
    break;
    
    // C99 6.8.2: compound-statement -> '{}' block
  case tok::l_brace:
    ParseCompoundStatement();
    break;
    // C99 6.8.3: expression[opt] ';'
  case tok::semi:
    ConsumeToken();
    break;
    
    // C99 6.8.4.1: if-statement
  case tok::kw_if:
    ParseIfStatement();
    break;
    
    
    // TODO: Handle OnlyStatement..
  }
}

/// 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 [TODO]
///         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
void Parser::ParseCompoundStatement() {
  assert(Tok.getKind() == tok::l_brace && "Not a compount stmt!");
  ConsumeBrace();  // eat the '{'.
  
  while (Tok.getKind() != tok::r_brace && Tok.getKind() != tok::eof)
    ParseStatementOrDeclaration(false);
  
  // We broke out of the while loop because we found a '}' or EOF.
  if (Tok.getKind() == tok::r_brace)
    ConsumeBrace();
  else
    Diag(Tok, diag::err_expected_rbrace);
}

/// ParseIfStatement
///       if-statement: [C99 6.8.4.1]
///         'if' '(' expression ')' statement
///         'if' '(' expression ')' statement 'else' statement
void Parser::ParseIfStatement() {
  assert(Tok.getKind() == tok::kw_if && "Not an if stmt!");
  ConsumeToken();  // eat the 'if'.

  if (Tok.getKind() != tok::l_paren) {
    Diag(Tok, diag::err_expected_lparen_after_if, "if");
    SkipUntil(tok::semi);
    return;
  }
  
  // Parse the condition.
  ParseParenExpression();
  
  // Read the if condition.
  ParseStatement();
  
  // If it has an else, parse it.
  if (Tok.getKind() == tok::kw_else) {
    ConsumeToken();
    ParseStatement();
  }
  
}