问题
I am working on a multiprocessor architectural simulator that uses Intel Pin to instrument C++ executable binaries and report interesting events (e.g., some function calls, thread create/finish, etc.). Basically, I build an instruction-decode cache of all instructions when their images are loaded and analyze instruction execution afterwards. So it is important for instruction addresses at image-load time to be the same as (or at least get updated synchronously with) instruction addresses at run-time.
Intel Pin API (e.g., IMG_AddInstrumentFunction) enables me to get information about the loaded images (executables and shared libraries) such as entry points, low/high address, etc.
However, I noticed that the instrumented program executes instructions at addresses that do not belong to any of the loaded images. By inspection, I am suspecting that the dynamic loader (image /lib64/ld-linux-x86-64.so.2 on 64-bit Centos 6.3) is relocating the main executable in memory by calling routine _dl_relocate_object.
I understand the need for relocatable code and all that stuff. I just need pointers to a good documentation (or just a brief description/advice) on how/when these relocations might happen (at load-time and runtime) so that I can take them into account in my architectural simulator. In other words, the mechanism used to achieve it (library functions that I need to instrument, conditions, or maybe randomization if there is any, g++ compiler switches that can be used to suppress relocation, etc). P.S.: I am only targeting x86/x86_64 architectures
回答1:
Relocation are processor specific, so ARM and x86-64 and x86 have different relocations (because their instruction set is different).
Relocation are also operating system specific, but some related OSes try to have the same relocations, e.g. Solaris and Linux for x86-64
They are described in detail in the ABI (application binary interface) specification "System V Application Binary Interface AMD64 Architecture Processor Supplement". The original x86-64 ABI used to be on http://www.x86-64.org/documentation.html but that site is not responding since several weeks. An old copy is on this link and a newer one is here
There is also the X32 ABI
See also this question.
来源：https://stackoverflow.com/questions/15470922/object-code-relocation-and-intel-pin-interaction