arm - 如何区分elf文件中的拇指指令和手臂指令？

Question

如标题所示，我想反汇编elf文件，但遇到了一个问题，我不知道哪个指令是arm指令，哪个是拇指指令。因为arm指令是32位的，而thumb指令是16位的，所以反汇编方式是不同的。那么如何从hex指令中检测出thumb指令呢？

Answer 1

In an ELF file, there is actually a straightforward method - just look at the function addresses in the symbol table. Much like target addresses for interworking branches, the bottom bit of the symbol address indicates the relevant instruction set - clear for ARM functions, and set for Thumb functions (see section 4.5.3 of the ARM ELF ABI).