27 Commits

Author SHA1 Message Date
Fangrui Song
72e75ca343 [MC][ELF] Allow STT_SECTION referencing SHF_MERGE on REL targets
This relands D64327 with a more specific workaround for R_386_GOTOFF
(gold<2.34 bug https://sourceware.org/bugzilla/show_bug.cgi?id=16794)

.debug_info has quite a few .debug_str relocations (R_386_32/R_ARM_ABS32).
The original workaround was too general and introduced too many .L symbols
used just as relocation targets.

From the original review:

  ... it reduced the size of a big ARM-32 debug image by 33%. It contained ~68M
  of relocations symbols out of total ~71M symbols (96% of symbols table was
  generated for relocations with symbol).
2020-12-20 18:37:14 -08:00
Mitch Phillips
382df1c674 Revert "Reland D64327 [MC][ELF] Allow STT_SECTION referencing SHF_MERGE on REL targets"
This reverts commit b497665d98ad5026b1d3d67d5793a28fefe27bea.

Spent some time trying to reproduce this locally, reverting in a
desparate attempt to fix the sanitizer buildbot:
 - http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux/builds/28828

I don't know exactly why or how this patch breaks the bots, but it seems
pretty concrete that it's the culprit.
2020-08-07 10:56:33 -07:00
Fangrui Song
b497665d98 Reland D64327 [MC][ELF] Allow STT_SECTION referencing SHF_MERGE on REL targets
This drops a GNU gold workaround and reverts the revert commit rL366708.

  Before binutils 2.34, gold -O2 and above did not correctly handle R_386_GOTOFF to
  SHF_MERGE|SHF_STRINGS sections: https://sourceware.org/bugzilla/show_bug.cgi?id=16794

From the original review:

  ... it reduced the size of a big ARM-32 debug image by 33%. It contained ~68M
  of relocations symbols out of total ~71M symbols (96% of symbols table was
  generated for relocations with symbol).

-Wl,-O2 (and -Wl,-O3) is so rare that we should just lower the
optimization level for LLVM_LINKER_IS_GOLD rather than pessimizing all users.
2020-08-02 18:05:17 -07:00
Elvina Yakubova
b36a3e6140 [llvm-readobj] Update tests because of changes in llvm-readobj behavior
This patch updates tests using llvm-readobj and llvm-readelf, because
soon reading from stdin will be achievable only via a '-' as described
here: https://bugs.llvm.org/show_bug.cgi?id=46400. Patch with changes to
llvm-readobj behavior is here: https://reviews.llvm.org/D83704

Differential Revision: https://reviews.llvm.org/D83912

Reviewed by: jhenderson, MaskRay, grimar
2020-07-20 10:39:04 +01:00
Vlad Tsyrklevich
5874a28ac5 Revert "Reland [ELF] Loose a condition for relocation with a symbol"
This reverts commit r366686 as it appears to be causing buildbot
failures on sanitizer-x86_64-linux-android and sanitizer-x86_64-linux.

llvm-svn: 366708
2019-07-22 17:48:53 +00:00
Nikola Prica
0166cff09b Reland [ELF] Loose a condition for relocation with a symbol
This patch was not the reason of the buildbot failure.

Deleted code was introduced as a work around for a bug in the gold linker
(http://sourceware.org/PR16794). Test case that was given as a reason for
this part of code, the one on previous link, now works for the gold.
This condition is too strict and when a code is compiled with debug info
it forces generation of numerous relocations with symbol for architectures
that do not have relocation addend.

Reviewers: arsenm, espindola

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D64327

llvm-svn: 366686
2019-07-22 13:07:01 +00:00
Nikola Prica
bbfa4cf70b Revert "[ELF] Loose a condition for relocation with a symbol"
This reverts commit 8507eca1647118e73435b0ce1de8a1952a021d01.

Reveting due to some suspicious failurse in santizer-x86_64-linux.

llvm-svn: 365685
2019-07-10 18:58:05 +00:00
Nikola Prica
fb163b4b20 [ELF] Loose a condition for relocation with a symbol
Deleted code was introduced as a work around for a bug in the gold linker
(http://sourceware.org/PR16794). Test case that was given as a reason for
this part of code, the one on previous link, now works for the gold.
This condition is too strict and when a code is compiled with debug info
it forces generation of numerous relocations with symbol for architectures
that do not have relocation addend.

Reviewers: arsenm, espindola

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D64327

llvm-svn: 365618
2019-07-10 11:17:48 +00:00
Fangrui Song
6afcdcf9ab [llvm-readobj] Change -t to --symbols in tests. NFC
-t is --symbols in llvm-readobj but --section-details (unimplemented) in readelf.
The confusing option should not be used since we aim for improving
compatibility.

Keep just one llvm-readobj -t use case in test/tools/llvm-readobj/symbols.test

llvm-svn: 359661
2019-05-01 09:28:24 +00:00
Fangrui Song
e29e30b139 [llvm-readobj] Change -long-option to --long-option in tests. NFC
We use both -long-option and --long-option in tests. Switch to --long-option for consistency.

In the "llvm-readelf" mode, -long-option is discouraged as it conflicts with grouped short options and it is not accepted by GNU readelf.

While updating the tests, change llvm-readobj -s to llvm-readobj -S to reduce confusion ("s" is --section-headers in llvm-readobj but --symbols in llvm-readelf).

llvm-svn: 359649
2019-05-01 05:27:20 +00:00
Francis Visoiu Mistrih
25528d6de7 [CodeGen] Unify MBB reference format in both MIR and debug output
As part of the unification of the debug format and the MIR format, print
MBB references as '%bb.5'.

The MIR printer prints the IR name of a MBB only for block definitions.

* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)->getNumber\(\)/" << printMBBReference(*\1)/g'
* find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)\.getNumber\(\)/" << printMBBReference(\1)/g'
* find . \( -name "*.txt" -o -name "*.s" -o -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#([0-9]+)/%bb.\1/g'
* grep -nr 'BB#' and fix

Differential Revision: https://reviews.llvm.org/D40422

llvm-svn: 319665
2017-12-04 17:18:51 +00:00
Daniel Jasper
41de8027b1 Revert r240302 ("Bring r240130 back.").
This causes errors like:

  ld: error: blah.o: requires dynamic R_X86_64_PC32 reloc against '' which
  may overflow at runtime; recompile with -fPIC
  blah.cc:function f(): error: undefined reference to ''
  blah.o:g(): error: undefined reference to ''

I have not yet come up with an appropriate reproduction.

llvm-svn: 240394
2015-06-23 11:31:32 +00:00
Rafael Espindola
2d6bae2e09 Bring r240130 back.
Now that pr23900 is fixed, we can bring it back with no changes.

Original message:

Make all temporary symbols unnamed.

What this does is make all symbols that would otherwise start with a .L
(or L on MachO) unnamed.

Some of these symbols still show up in the symbol table, but we can just
make them unnamed.

In order to make sure we produce identical results when going thought assembly,
all .L (not just the compiler produced ones), are now unnamed.

Running llc on llvm-as.opt.bc, the peak memory usage goes from 208.24MB to
205.57MB.

llvm-svn: 240302
2015-06-22 17:52:52 +00:00
Nico Weber
67e715ff7d Revert 240130, it caused crashes (repro in PR23900).
llvm-svn: 240193
2015-06-19 23:43:47 +00:00
Rafael Espindola
284a750c5f Make all temporary symbols unnamed.
What this does is make all symbols that would otherwise start with a .L
(or L on MachO) unnamed.

Some of these symbols still show up in the symbol table, but we can just
make them unnamed.

In order to make sure we produce identical results when going thought assembly,
all .L (not just the compiler produced ones), are now unnamed.

Running llc on llvm-as.opt.bc, the peak memory usage goes from 208.24MB to
205.57MB.

llvm-svn: 240130
2015-06-19 12:16:55 +00:00
Rafael Espindola
a401eee22f Omit unused section symbols from the symbol table.
Section symbols exist as an optimization: instead of having multiple relocations
point to different symbols, many of them can point to a single section symbol.

When that optimization is unused, a section symbol is also unused and adds no
extra information to the object file.

This saves a bit of space on the object files and makes the output of
llvm-objdump -t easier to read and consequently some tests get quite a bit
simpler.

llvm-svn: 239045
2015-06-04 15:33:30 +00:00
Rafael Espindola
10f3de6889 Update tests to not be as dependent on section numbers.
Many of these predate llvm-readobj. With elf-dump we had to match
a relocation to symbol number and symbol number to symbol name or
section number.

llvm-svn: 235015
2015-04-15 15:59:37 +00:00
Rafael Espindola
b1b49789d0 Work around gold bug http://sourceware.org/PR16794.
llvm-svn: 205416
2014-04-02 12:15:20 +00:00
Rafael Espindola
4f60a38f18 Change how we iterate over relocations on ELF.
For COFF and MachO, sections semantically have relocations that apply to them.
That is not the case on ELF.

In relocatable objects (.o), a section with relocations in ELF has offsets to
another section where the relocations should be applied.

In dynamic objects and executables, relocations don't have an offset, they have
a virtual address. The section sh_info may or may not point to another section,
but that is not actually used for resolving the relocations.

This patch exposes that in the ObjectFile API. It has the following advantages:

* Most (all?) clients can handle this more efficiently. They will normally walk
all relocations, so doing an effort to iterate in a particular order doesn't
save time.

* llvm-readobj now prints relocations in the same way the native readelf does.

* probably most important, relocations that don't point to any section are now
visible. This is the case of relocations in the rela.dyn section. See the
updated relocation-executable.test for example.

llvm-svn: 182908
2013-05-30 03:05:14 +00:00
Nico Rieck
ba848e3bca Replace coff-/elf-dump with llvm-readobj
llvm-svn: 179361
2013-04-12 04:06:46 +00:00
Rafael Espindola
77dde89b90 Fix the bitwidth of the remaining fields.
llvm-svn: 136884
2011-08-04 17:00:11 +00:00
Rafael Espindola
96df560ce1 print st_type with the correct number of bits.
llvm-svn: 136875
2011-08-04 15:24:00 +00:00
Rafael Espindola
79ef75dc49 Print st_bind with the correct number of bits.
llvm-svn: 136874
2011-08-04 15:10:35 +00:00
Rafael Espindola
260af5cef6 Print r_type with the correct number of bits.
llvm-svn: 136872
2011-08-04 14:39:30 +00:00
Rafael Espindola
65c559c5fb Change anther counter to decimal.
llvm-svn: 136870
2011-08-04 14:01:03 +00:00
Rafael Espindola
1557fd6d39 Write the section table and the section data in the same order that
gun as does. This makes it a lot easier to compare the output of both
as the addresses are now a lot closer.

llvm-svn: 127972
2011-03-20 18:44:20 +00:00
Evan Cheng
f02ca16ba7 Convert MC tests to .s so codegen changes won't break them.
llvm-svn: 122786
2011-01-03 23:47:14 +00:00