How to recover the C++ try/throw/catch block length and address from machine code?

Question

I'm doing a project that reorders basic blocks inside a function at runtime in C++ under 64-bit Linux. Of course, the reordering process includes updating instructions like "jmp", etc. One problem is that if (I guess) the compiler (clang++ or g++) determines the try{...} block using a range, ie, from address1 to address2; the reordered code would have problems (some basic blocks are moved out of range and some new basic blocks are swapped in).

My question is: Does the compiler/program determines the try{...} block using a range? If so, or not, how can I know and modify the corresponding determinants, through which I can recover the try/throw/catch blocks and let the program execute normally after reordering; when the program has been already loaded into memory?

Answer 1

FYI, here is the relevant document for LLVM's implementation for try-catch. g++ does something very similar.

When you say by range, I would assume you are thinking the compiler would assume the code instruction from 0x0010 to 0x0020 is code, and instruction from 0x0020 to 0x0024 is for the catch block. From the LLVM specification, it doesn't rely on such assumption.

Edit:

here is some more reading for the implementation for how g++ and clang implements try-catch