比较不同变量类型的变量的 Clang AST 匹配器

Clang AST matcher for variables compared to different variable types

我是 clang-tidy 的新手,以下是练习,因此我可以转向更复杂的匹配器和工具。

假设我们有

typedef int my_type;
void foo()
{
       int x = 0;//this should be identified as need to be fixed
       my_type z = 0;
       if( x == z){
               //match this case
       }

}

我的目标是识别与 "my_type" 进行比较的变量,以便通过将它们的类型更改为 my_type 来修复它们的声明。

现在我正在尝试执行以下操作

     auto my_type_decl = varDecl(hasType(asString("my_type")));
     auto my_type_decl_exp= declRefExpr(to(my_type_decl));
     auto binop = binaryOperator(has(implicitCastExpr(has(my_type_decl_exp))));
     auto other_decl_exp = declRefExpr(hasAncestor(binop), unless(to(my_type_decl)));
     //get ancestor functionDecl
     //get descendant varDecls that match the other_decl_exp

这里的问题是我忽略了上下文。 处理此类事情的正确方法是什么?

您可以将节点匹配器绑定到一个名称,然后从匹配结果中检索这些节点。

例如:

// Match binary operators
binaryOperator(
    // that are equality comparisons,
    hasOperatorName("=="),
    // where one side refers to a variable
    hasEitherOperand(ignoringImpCasts(declRefExpr(to(varDecl(
        // whose type is a typedef or type alias
        hasType(typedefNameDecl(
            // named "::my_type"
            hasName("::my_type"),
            // that aliases any type, which is bound to the name "aliased",
            hasType(type().bind("aliased"))))))))),
    // and where one side refers to a variable
    hasEitherOperand(ignoringImpCasts(declRefExpr(to(varDecl(
        // whose type is the same as the type bound to "aliased",
        // which is bound to the name "declToChange".
        hasType(type(equalsBoundNode("aliased")))).bind("declToChange"))))));

然后:

const auto *declToChange = result.Nodes.getNodeAs<VarDecl>("declToChange");

请注意,这匹配相等比较,因此 declToChange 可能在多个匹配项中指向相同的 VarDecl

在以下示例中,此匹配器将生成两个匹配项,其中 declToChange 绑定到 x,none 且 declToChange 绑定到 y

typedef int my_type;

void foo() {
  int x = 0;
  int y = 0;
  my_type z = 0;

  if (x == z) {
  }

  if (z == x) {
  }
}