如何在使用clang的另一条语句之前插入一条语句 [英] How to instrument a statement just before another statement using clang

问题描述

我必须通过在clang前面添加一条语句来对某些语句进行检测.我有一个指向Expr对象的指针，使用它需要在包含该对象的语句之前插入另一个语句.现在，我正在使用一种骇人听闻的方法，该方法只是将SourceLocation指针移回，直到看到一个；或}或{.但这并不适用于所有情况.例如，当我尝试插入for语句时，它将失败. clang中是否有任何类提供了一种更简洁的方法来实现此目的?

I have to instrument certain statements in clang by adding a statement just before it. I have a pointer to an Expr object using which I need to insert another statement just before the statement containing it. Right now I am using a hacky approach which just moves back the SourceLocation pointer till I see a ; or } or {. But this does not work for all cases. eg when I try to instrument a for statement, it fails. Is there any class in clang which provides a method to do this in a more cleaner way?

这是我的代码段.我需要在包含指针取消引用的语句之前插入一个断言.

Here is snippet of my code. I need to insert an assert just before the statement containing a pointer dereference.

bool MyRecursiveASTVisitor::VisitUnaryOperator(UnaryOperator *E){
    if (E->getOpcode() == UO_Deref ){
        Expr *e1 = E->getSubExpr();
        SourceLocation SL = E->getLocStart();
    }
    return true;
}

推荐答案

您可以使用返回 SourceRange SourceRange类的语句上的getSourceRange() getBegin()，它将返回 SourceLocation .

You can use getSourceRange() on the statement which returns SourceRange SourceRange Class has getBegin() which will return SourceLocation.

您可以结帐 https://github.com/eschulte/clang-mutate 和在那里看到一个例子...

you can checkout https://github.com/eschulte/clang-mutate and see an example there...

编辑:

为了从Stmt中提取Expr，您可以检出此SO问题

In order to extract Expr out of Stmt you can checkout this SO question How to get Stmt class object from Expr object in Clang

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