llvm with tablegen backend for capstone disassembler

Vasily Leonenko ad79d51778 [PR] Instrumentation: Generate and use _start and _fini trampolines ... Summary: This commit implements new method for _start & _fini functions hooking which allows to use relative jumps for future PIE & .so library support. Instead of using absolute address of _start & _fini functions known on linking stage - we'll use dynamically created trampoline functions and use corresponding symbols in instrumentation runtime library. As we would like to use instrumentation for dynamically loaded binaries (with PIE & .so), thus we need to compile instrumentation library with "-fPIC" flag to support relative address resolution for functions and data. For shared libraries we need to handle initialization of instrumentation library case by using DT_INIT section entry point. Also this commit adds detection if the binary is executable or shared library based on existence of PT_INTERP header. In case of shared library we save information about real library init function address for further usage for instrumentation library init trampoline function creation and also update DT_INIT to point instrumentation library init function. Functions called from init/fini functions should be called with forced stack alignment to avoid issues with instructions which relies on it. E.g. optimized string operations. Vasily Leonenko, Advanced Software Technology Lab, Huawei (cherry picked from FBD30092316)		2021-06-19 04:08:35 +08:00
bolt	[PR] Instrumentation: Generate and use _start and _fini trampolines	2021-06-19 04:08:35 +08:00