C-使用Clang AST用宏代替表达式

Question

我希望借助clang ast Matcher。

foo(NUM << DEV_SHIFT | DEVICE);

to

foo(ADDR(NUM, DEVICE));

#define ADDR(a, b) (((a) << NUM_SHIFT) | (b))

我有以下AST匹配器，似乎可以很好地识别代码。

Finder->addMatcher(
       callExpr(hasArgument(                                                                                                                                                             
           0, binaryOperator(hasOperatorName("|"),
                             hasLHS(ignoringParenImpCasts(
                                 binaryOperator(hasOperatorName("<<")))))
                  .bind("replaceWithMacro"))),
       this);

但是我有一个问题要了解如何编写检查和翻译。我目前坚持使用此代码：

void FirstCheckCheck::check(const MatchFinder::MatchResult &Result) {
  // FIXME: Add callback implementation.
  if (const auto MatchedDecl =
          Result.Nodes.getNodeAs<CallExpr>("replaceWithMacro")) {
    diag(MatchedDecl->getExprLoc(), "CallExp");
  } else if (const auto MatchedDecl =
                 Result.Nodes.getNodeAs<Expr>("replaceWithMacro")) {
    diag(MatchedDecl->getExprLoc(), "Expr");
    diag(MatchedDecl->getBeginLoc(), "BeginLOC");
    diag(MatchedDecl->getEndLoc(), "EndLOC");
  }

我不知道如何将两个变量作为字符串提取。我正在查看Expr类的文档(http://clang.llvm.org/doxygen/classclang_1_1 expr.html(，但我找不到有用的东西。

如果有人可以将我指向正确的方向，这将不胜感激。

添加编辑。

Answer 1

这是我非常满意的解决方案。它基于Boq从评论中提出的建议。

//===--- FirstCheckCheck.cpp - clang-tidy ---------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "FirstCheckCheck.h"
#include "clang/AST/ASTContext.h"
#include "clang/ASTMatchers/ASTMatchFinder.h"
using namespace clang::ast_matchers;
namespace clang {
namespace tidy {
namespace misc {
void FirstCheckCheck::registerMatchers(MatchFinder *Finder) {
  // FIXME: Add matchers.
  //
  Finder->addMatcher(
      callExpr(hasArgument(
          1,
          binaryOperator(
              hasOperatorName("|"),
              hasRHS(ignoringImplicit(
                  anyOf(declRefExpr().bind("moduleNum"), integerLiteral().bind(
                      "moduleNum")))),
              hasLHS(ignoringParens(
                  binaryOperator(hasOperatorName("<<"),
                                 hasLHS(ignoringImplicit(anyOf(
                                     declRefExpr().bind("deviceNum"),
                                     integerLiteral().bind("deviceNum"))))))))
              .bind("replaceWithMacro"))),
      this);
}
void FirstCheckCheck::check(const MatchFinder::MatchResult &Result) {
  // FIXME: Add callback implementation.
    std::string deviceNumString;
    std::string moduleNumString;
    std::string ReplacementText;
  if (const auto MatchedDecl =
          Result.Nodes.getNodeAs<Expr>("deviceNum")) {
    const LangOptions &Opts = getLangOpts();
    /* get device string */
    deviceNumString = Lexer::getSourceText(
        CharSourceRange::getTokenRange(MatchedDecl->getSourceRange()),
        *Result.SourceManager, Opts);
  }
  /* ((uint16_t)(deviceNum << 8 | moduleNum)) */
  if (const auto MatchedDecl =
          Result.Nodes.getNodeAs<Expr>("moduleNum")) {
    const LangOptions &Opts = getLangOpts();
    moduleNumString = Lexer::getSourceText(
        CharSourceRange::getTokenRange(MatchedDecl->getSourceRange()),
        *Result.SourceManager, Opts);
  }
  if (const auto MatchedDecl =
                 Result.Nodes.getNodeAs<Expr>("replaceWithMacro")) {
    const LangOptions &Opts = getLangOpts();
    ReplacementText = Lexer::getSourceText(
        CharSourceRange::getTokenRange(MatchedDecl->getSourceRange()),
        *Result.SourceManager, Opts);
    std::string replacementString =
        "ADDR(" + deviceNumString + ", " + moduleNumString + ")";
    FixItHint Hint = FixItHint::CreateReplacement(
        MatchedDecl->getSourceRange(), replacementString);
    diag(MatchedDecl->getBeginLoc(), "Replace with ADDR() macro") << Hint;
  }
  /* diag(MatchedDecl->getLocation(), "insert 'awesome'", DiagnosticIDs::Note)
   */
  /*     << FixItHint::CreateInsertion(MatchedDecl->getLocation(), "awesome_");
   */
}
} // namespace misc
} // namespace tidy
} // namespace clang