Commit Graph

8 Commits

Author SHA1 Message Date
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 75d5b5495f Fix the interpretation of a 0 st_name.
The ELF spec is very clear:

-----------------------------------------------------------------------------
If the value is non-zero, it represents a string table index that gives the
symbol name. Otherwise, the symbol table entry has no name.
--------------------------------------------------------------------------

In particular, a st_name of 0 most certainly doesn't mean that the symbol has
the same name as the section.

llvm-svn: 238899
2015-06-03 05:14:22 +00:00
Rafael Espindola bb35ebd189 Don't special case undefined symbol when deciding the symbol order.
ELF has no restrictions on where undefined symbols go relative to other defined
symbols. In fact, gas just sorts them together. Do the same.

This was there since r111174 probably just because the MachO writer has it.

llvm-svn: 238513
2015-05-28 21:59:34 +00:00
Rafael Espindola cad91323dc Don't constrain the section order in tests that don't depend on it.
llvm-svn: 236102
2015-04-29 13:55:07 +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 5904e12bfa Completely rewrite ELFObjectWriter::RecordRelocation.
I started trying to fix a small issue, but this code has seen a small fix too
many.

The old code was fairly convoluted. Some of the issues it had:

* It failed to check if a symbol difference was in the some section when
  converting a relocation to pcrel.
* It failed to check if the relocation was already pcrel.
* The pcrel value computation was wrong in some cases (relocation-pc.s)
* It was missing quiet a few cases where it should not convert symbol
  relocations to section relocations, leaving the backends to patch it up.
* It would not propagate the fact that it had changed a relocation to pcrel,
  requiring a quiet nasty work around in ARM.
* It was missing comments.

llvm-svn: 205076
2014-03-29 06:26:49 +00:00
Rafael Espindola cfee7efde9 Teach llvm-readobj to print human friendly description of reserved sections.
llvm-svn: 204584
2014-03-24 05:00:34 +00:00
David Peixotto c0f92a2dc9 Fix parsing of .symver directive on ARM
ARM assembly syntax uses @ for a comment, execpt for the second
parameter of the .symver directive which requires @ as part of the
symbol name. This commit fixes the parsing of this directive by
adding a special case for ARM for this one argumnet.

To make the change we had to move the AllowAtInIdentifier variable
to the MCAsmLexer interface (from AsmLexer) and expose a setter for
the value.  The ELFAsmParser then toggles this value when parsing
the second argument to the .symver directive for a target that
uses @ as a comment symbol

llvm-svn: 199339
2014-01-15 22:40:02 +00:00