Commit Graph

5 Commits

Author SHA1 Message Date
Fangrui Song b159906a9a [test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC
Also change some options that have different semantics (cause confusion) in llvm-readelf mode:

-s => -S
-t => --symbols
-sd => --section-data

llvm-svn: 359651
2019-05-01 05:49:01 +00:00
Fangrui Song 07f8daf05e [ELF] Simplify RelRo, TLS, NOBITS section ranks and make RW PT_LOAD start with RelRo
Old: PT_LOAD(.data | PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .bss)
New: PT_LOAD(PT_GNU_RELRO(.data.rel.ro .bss.rel.ro) | .data .bss)

The placement of | indicates page alignment caused by PT_GNU_RELRO. The
new layout has simpler rules and saves space for many cases.

Old size: roundup(.data) + roundup(.data.rel.ro)
New size: roundup(.data.rel.ro + .bss.rel.ro) + .data

Other advantages:

* At runtime the 3 memory mappings decrease to 2.
* start(PT_TLS) = start(PT_GNU_RELRO) = start(RW PT_LOAD). This
  simplifies binary manipulation tools.
  GNU strip before 2.31 discards PT_GNU_RELRO if its
  address is not equal to the start of its associated PT_LOAD.
  This has been fixed by https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=f2731e0c374e5323ce4cdae2bcc7b7fe22da1a6f
  But with this change, we will be compatible with GNU strip before 2.31
* Before, .got.plt (non-relro by default) was placed before .got (relro
  by default), which made it impossible to have _GLOBAL_OFFSET_TABLE_
  (start of .got.plt on x86-64) equal to the end of .got (R_GOT*_FROM_END)
  (https://bugs.llvm.org/show_bug.cgi?id=36555). With the new ordering, we
  can improve on this regard if we'd like to.

Reviewers: ruiu, espindola, pcc

Subscribers: emaste, arichardson, llvm-commits, joerg, jdoerfert

Differential Revision: https://reviews.llvm.org/D56828

llvm-svn: 356117
2019-03-14 03:47:45 +00:00
Joel Jones a5752e199c [lld] Add REQUIRES: x86 where needed to tests
If building lld without x86 support, tests that require that support should
be treated as unsupported, not errors.

Tested using:
  1. cmake '-DLLVM_TARGETS_TO_BUILD=AArch64;X86'
     make check-lld
     =>
     Expected Passes    : 1406
     Unsupported Tests  : 287

  2. cmake '-DLLVM_TARGETS_TO_BUILD=AArch64'
     make check-lld
     =>
     Expected Passes    : 410
     Unsupported Tests  : 1283

Patch by Joel Jones

Differential Revision: https://reviews.llvm.org/D47748

llvm-svn: 334095
2018-06-06 13:56:51 +00:00
Peter Collingbourne 628ec9f193 ELF: Place relro sections after non-relro sections in r/w segment.
This is in preparation for my next change, which will introduce a relro
nobits section. That requires that relro sections appear at the end of the
progbits part of the r/w segment so that the relro nobits section can appear
contiguously.

Because of the amount of churn required in the test suite, I'm making this
change separately.

llvm-svn: 291523
2017-01-10 01:21:30 +00:00
Rafael Espindola 4ee6cb3a70 Document and test the first few .got.plt entries.
llvm-svn: 268945
2016-05-09 18:12:15 +00:00