ABI and API compatibility — libgccjit v6.1.0 ( ) documentation (original) (raw)

The libgccjit developers strive for ABI and API backward-compatibility: programs built against libgccjit.so stand a good chance of running without recompilation against newer versions of libgccjit.so, and ought to recompile without modification against newer versions of libgccjit.h.

Note

The libgccjit++.h C++ API is more experimental, and less locked-down at this time.

API compatibility is achieved by extending the API rather than changing it. For ABI compatiblity, we avoid bumping the SONAME, and instead use symbol versioning to tag each symbol, so that a binary linked against libgccjit.so is tagged according to the symbols that it uses.

For example, gcc_jit_context_add_command_line_option() was added inLIBGCCJIT_ABI_1. If a client program uses it, this can be detected from metadata by using objdump:

$ objdump -p testsuite/jit/test-extra-options.c.exe | tail -n 8

Version References: required from libgccjit.so.0: 0x00824161 0x00 04 LIBGCCJIT_ABI_1 0x00824160 0x00 03 LIBGCCJIT_ABI_0 required from libc.so.6:

You can see the symbol tags provided by libgccjit.so using objdump:

$ objdump -p libgccjit.so | less [...snip...] Version definitions: 1 0x01 0x0ff81f20 libgccjit.so.0 2 0x00 0x00824160 LIBGCCJIT_ABI_0 3 0x00 0x00824161 LIBGCCJIT_ABI_1 LIBGCCJIT_ABI_0 [...snip...]