MacroExpander.cpp

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//===--- MacroExpander.cpp - Format C++ code --------------------*- C++ -*-===//
//
// 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
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file contains the implementation of MacroExpander, which handles macro
/// configuration and expansion while formatting.
///
//===----------------------------------------------------------------------===//
 
#include "Macros.h"
 
#include "Encoding.h"
#include "FormatToken.h"
#include "FormatTokenLexer.h"
#include "clang/Basic/TokenKinds.h"
#include "clang/Format/Format.h"
#include "clang/Lex/HeaderSearch.h"
#include "clang/Lex/HeaderSearchOptions.h"
#include "clang/Lex/Lexer.h"
#include "clang/Lex/ModuleLoader.h"
#include "clang/Lex/Preprocessor.h"
#include "clang/Lex/PreprocessorOptions.h"
#include "llvm/ADT/StringSet.h"
#include "llvm/Support/ErrorHandling.h"
 
namespace clang {
namespace format {
 
struct MacroExpander::Definition {
  StringRef Name;
  SmallVector<FormatToken *, 8> Params;
  SmallVector<FormatToken *, 8> Body;
 
  // Map from each argument's name to its position in the argument list.
  // With "M(x, y) x + y":
  //   x -> 0
  //   y -> 1
  llvm::StringMap<size_t> ArgMap;
 
  bool ObjectLike = true;
};
 
class MacroExpander::DefinitionParser {
public:
  DefinitionParser(ArrayRef<FormatToken *> Tokens) : Tokens(Tokens) {
    assert(!Tokens.empty());
    Current = Tokens[0];
  }
 
  // Parse the token stream and return the corresponding Definition object.
  // Returns an empty definition object with a null-Name on error.
  MacroExpander::Definition parse() {
    if (Current->isNot(tok::identifier))
      return {};
    Def.Name = Current->TokenText;
    nextToken();
    if (Current->is(tok::l_paren)) {
      Def.ObjectLike = false;
      if (!parseParams())
        return {};
    }
    if (!parseExpansion())
      return {};
 
    return Def;
  }
 
private:
  bool parseParams() {
    assert(Current->is(tok::l_paren));
    nextToken();
    while (Current->is(tok::identifier)) {
      Def.Params.push_back(Current);
      Def.ArgMap[Def.Params.back()->TokenText] = Def.Params.size() - 1;
      nextToken();
      if (Current->isNot(tok::comma))
        break;
      nextToken();
    }
    if (Current->isNot(tok::r_paren))
      return false;
    nextToken();
    return true;
  }
 
  bool parseExpansion() {
    if (!Current->isOneOf(tok::equal, tok::eof))
      return false;
    if (Current->is(tok::equal))
      nextToken();
    parseTail();
    return true;
  }
 
  void parseTail() {
    while (Current->isNot(tok::eof)) {
      Def.Body.push_back(Current);
      nextToken();
    }
    Def.Body.push_back(Current);
  }
 
  void nextToken() {
    if (Pos + 1 < Tokens.size())
      ++Pos;
    Current = Tokens[Pos];
    Current->Finalized = true;
  }
 
  size_t Pos = 0;
  FormatToken *Current = nullptr;
  Definition Def;
  ArrayRef<FormatToken *> Tokens;
};
 
MacroExpander::MacroExpander(
    const std::vector<std::string> &Macros, SourceManager &SourceMgr,
    const FormatStyle &Style,
    llvm::SpecificBumpPtrAllocator<FormatToken> &Allocator,