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[0/6,RS6000] inline plt call support

Message ID 20181107053326.GM29482@bubble.grove.modra.org
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Series inline plt call support | expand

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Alan Modra Nov. 7, 2018, 5:33 a.m. UTC 
Hi Segher,
This is the patch series you already saw earlier this year, rebased
to recent gcc, and with a comment or two fixed.  The first five
patches tidy and rearrange the function call code in order to support
inline plt calls without a huge increase in rs6000.md.  As is, inline
plt calls are supported for powerpc-linux and powerpc64le-linux
ELFv2.  I don't support them for powerpc64-linux ELFv1 due to the
extra read barriers needed there, but it wouldn't be too difficult to
support if there was demand.

I've regression tested again on powerpc64le-linux.  Earlier testing
went to some lengths with old and new binutils on powerpc-linux,
powerpc64le-linux and powerpc64-linux.  I also tested using -fno-plt
in bootstrap and regression tests, which unsurprisingly showed
numerous fails due to wrong counts of symbols (inline plt references a
function symbol multiple times to make a call), wrong "bl" counts
(none with inline call) or similar.  I didn't see anything
frightening, and I expect that people generally won't regression test
with -fno-plt, so I haven't modified any tests.

One benefit of the inline plt support is that gcc will now use the new
sequences and relocs to support -mlongcall.  This allows lazy dynamic
resolution of the plt entries so it is now possible to dlopen
libraries and have -mlongcall code call functions in those libraries.
That wasn't possible before.  See
https://bugzilla.redhat.com/show_bug.cgi?id=1633721

Alan Modra (6):
  [RS6000] rs6000_output_call for external call insn assembly output
  [RS6000] rs6000_output_indirect_call
  [RS6000] Replace TLSmode with P, and correct tls call mems
  [RS6000] Remove constraints on call rounded_stack_size_rtx arg
  [RS6000] Use standard call patterns for __tls_get_addr calls
  [RS6000] inline plt call sequences

 gcc/config.in                     |    6 +
 gcc/config/rs6000/darwin.md       |    8 +-
 gcc/config/rs6000/predicates.md   |   25 +
 gcc/config/rs6000/rs6000-protos.h |    8 +-
 gcc/config/rs6000/rs6000.c        |  617 ++++++++++++++---
 gcc/config/rs6000/rs6000.h        |    4 +
 gcc/config/rs6000/rs6000.md       | 1023 +++++++++++++----------------
 gcc/configure                     |   36 +
 gcc/configure.ac                  |    6 +
 9 files changed, 1065 insertions(+), 668 deletions(-)