Change -gz and -Wa,--compress-debug-sections to use gABI compression (SHF_COMPRESSED)
authorFangrui Song <maskray@google.com>
Fri, 10 May 2019 02:08:21 +0000 (02:08 +0000)
committerFangrui Song <maskray@google.com>
Fri, 10 May 2019 02:08:21 +0000 (02:08 +0000)
commitbdb21337e6e1732c9895966449c33c408336d295
tree531fcfb6a81caacbce95a57ac4946807ae541685
parentea38ac5ba3148e72dc1a260910ef65d2f623e0b5
Change -gz and -Wa,--compress-debug-sections to use gABI compression (SHF_COMPRESSED)

Since July 15, 2015 (binutils-gdb commit
19a7fe52ae3d0971e67a134bcb1648899e21ae1c, included in 2.26), gas
--compress-debug-sections=zlib (gcc -gz) means zlib-gabi:
SHF_COMPRESSED. Before that it meant zlib-gnu (.zdebug).

clang's -gz was introduced in rC306115 (Jun 2017) to indicate zlib-gnu. It
is 2019 now and it is not unreasonable to assume users of the new
feature to have new linkers (ld.bfd/gold >= 2.26, lld >= rLLD273661).

Change clang's default accordingly to improve standard conformance.
zlib-gnu becomes out of fashion and gets poorer toolchain support.
Its mangled names confuse tools and are more likely to cause problems.

Reviewed By: compnerd

Differential Revision: https://reviews.llvm.org/D61689

llvm-svn: 360403
clang/docs/ReleaseNotes.rst
clang/lib/Frontend/CompilerInvocation.cpp
clang/tools/driver/cc1as_main.cpp