Commit Graph

9 Commits

Author SHA1 Message Date
Rafael Espindola e3a20f57d9 Fix pr24486.
This extends the work done in r233995 so that now getFragment (in addition to
getSection) also works for variable symbols.

With that the existing logic to decide if a-b can be computed works even if
a or b are variables. Given that, the expression evaluation can avoid expanding
variables as aggressively and that in turn lets the relocation code see the
original variable.

In order for this to work with the asm streamer, there is now a dummy fragment
per section. It is used to assign a section to a symbol when no other fragment
exists.

This patch is a joint work by Maxim Ostapenko andy myself.

llvm-svn: 249303
2015-10-05 12:07:05 +00:00
David Majnemer f4dc456eef llvm-readobj: pretty-print special COFF section names
Print IMAGE_SYM_DEBUG and the like instead of (-2).

llvm-svn: 218172
2014-09-20 00:25:06 +00:00
David Majnemer 44f51e5113 Object: Add support for bigobj
This adds support for reading the "bigobj" variant of COFF produced by
cl's /bigobj and mingw's -mbig-obj.

The most significant difference that bigobj brings is more than 2**16
sections to COFF.

bigobj brings a few interesting differences with it:
- It doesn't have a Characteristics field in the file header.
- It doesn't have a SizeOfOptionalHeader field in the file header (it's
  only used in executable files).
- Auxiliary symbol records have the same width as a symbol table entry.
  Since symbol table entries are bigger, so are auxiliary symbol
  records.

Write support will come soon.

Differential Revision: http://reviews.llvm.org/D5259

llvm-svn: 217496
2014-09-10 12:51:52 +00:00
David Majnemer 299674e94f MC: Let non-temporary COFF aliases be in symtab
MC was aping a binutils bug where aliases would default their linkage to
private instead of internal.

I've sent a patch to the binutils maintainers and they've recently
applied it to the GNU assembler sources.

This fixes PR20152.

Differential Revision: http://reviews.llvm.org/D4395

llvm-svn: 212899
2014-07-13 04:31:19 +00:00
Saleem Abdulrasool e9bd916efe MC: prevent early DCE of empty sections
Prevent the early elimination of sections in the object writer.  There may be
references to the section itself by other symbols, which may potentially not be
possible to resolve.  ML (Visual Studio's Macro Assembler) also seems to retain
empty sections.

The elimination of symbols and sections which are unused should really occur at
the link phase.  This will not cause any change in the resulting binary, simply
in the generated object files.

The adjustments to the other unit tests account for the fluctuating section
index caused by the appearance of sections which were previously discarded.

llvm-svn: 210373
2014-06-06 21:40:16 +00:00
Rafael Espindola ea9f9d4030 Don't propagate StorageClass and ComplexType to aliases.
This matches gas' behaviour on COFF.

I think that this yak is now sufficiently shaved for aliases with offset
to work.

llvm-svn: 207786
2014-05-01 19:02:03 +00:00
Reid Kleckner 8b2ad2a962 Revert "COFF: Emit all MCSymbols rather than filtering out some of them"
This reverts commit r190888, to fix PR17967.  The original change wasn't
the right way to get @feat.00 into the object file.  The right fix is to
make @feat.00 be a global symbol.

llvm-svn: 195053
2013-11-18 23:08:12 +00:00
Reid Kleckner 3ea536fef4 COFF: Emit all MCSymbols rather than filtering out some of them
In particular, this means we emit non-external symbols defined to
variables, such as aliases or absolute addresses.

This is needed to implement /safeseh, and it appears there was some
confusion about what symbols to emit previously.

llvm-svn: 190888
2013-09-17 21:24:44 +00:00
Reid Kleckner dae7b4e4d1 [mc-coff] Resolve aliases when emitting COFF relocations
This is consistent with the ELF object writer.

Add some COFF tests that relocate against an alias.

Reviewers: espindola

Differential Revision: http://llvm-reviews.chandlerc.com/D1079

llvm-svn: 186341
2013-07-15 19:41:21 +00:00