Commit Graph

48 Commits

Author SHA1 Message Date
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
Fangrui Song f72cdb50be [MC] [X86] Teach leaq _GLOBAL_OFFSET_TABLE(%rip), %r15 to use R_X86_64_GOTPC32 instead of R_X86_64_PC32
Summary:
This is similar to D46319 (ARM). x86-64 psABI p40 gives an example:

  leaq _GLOBAL_OFFSET_TABLE(%rip), %r15 # GOTPC32 reloc

GNU as creates R_X86_64_GOTPC32. However, MC currently emits R_X86_64_PC32.

Reviewers: javed.absar, echristo

Subscribers: kristof.beyls, llvm-commits, peter.smith, grimar

Differential Revision: https://reviews.llvm.org/D47507

llvm-svn: 334515
2018-06-12 16:20:44 +00:00
Rafael Espindola b718237dfc Accept subtractions involving a weak symbol.
When a symbol S shows up in an expression in assembly there are two
possible interpretations
* The expression is referring to the value of S in this file.
* The expression is referring to the value after symbol resolution.

In the first case the assembler can reason about the value and try to
produce a relocation.
In the second case, that is only possible if the symbol cannot be
preempted.

Assemblers are not very consistent about which interpretation gets used.
This changes MC to agree with GAS in the case of an expression of the
form "Sym - WeakSym".

llvm-svn: 258329
2016-01-20 18:57:48 +00:00
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
Rafael Espindola f3d49b30b5 Handle 16 bit PC relative relocations.
Fixes pr23771.

llvm-svn: 239214
2015-06-06 02:29:56 +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 29c8270916 Look past locals in comdats.
We have to avoid converting a reference to a global into a reference to a local,
but it is fine to look past a local.

Patch by Vasileios Kalintiris.

I just moved the comment and added thet test.

llvm-svn: 235300
2015-04-20 12:44:06 +00:00
Rafael Espindola db8a58688d Compute A-B if both A and B are in the same comdat section.
Part of pr23272.

A small annoyance with the assembly syntax we implement is that given an
expression there is no way to know if what is desired is the value of that
expression for the symbols in this file or for the final values of those
symbols in a link.

The first case is useful for use in sections that get discarded or ignored
if the section they are describing is discarded.

For axample, consider A-B where A and B are in the same comdat section.

We can compute the value of the difference in the section that is present in
the current .o and if that section survives to the final DSO the value will
still will be correct.

But the section is in a comdat. Another section from another object file
might be used istead. We know that that section will define A and B, but
we have no idea what the value of A-B might be.

In practice we have to assume that the intention is to compute the value
in the current section since otherwise the is no way to create something like
the debug aranges section.

llvm-svn: 235222
2015-04-17 20:05:17 +00:00
Rafael Espindola bdfbde56e0 Reorganize the x86 ELF relocation selection logic.
The main differences are:

* Split in 32 and 64 bit functions.
* First switch on the Modifier so that we have only one non fully covered
  switch.
* Map the fixup kind first to a x86_64 (or i386) specific enum, to make
  it easy to handle cases like X86::reloc_riprel_4byte_movq_load.
* Switch on IsPCRel last, which reduces code duplication.

Fixes pr22308.

llvm-svn: 232837
2015-03-20 19:48:54 +00:00
Davide Italiano fcae934c03 [MC][Target] Implement support for R_X86_64_SIZE{32,64}.
Differential Revision:	D7990
Reviewed by:	rafael, majnemer

llvm-svn: 231216
2015-03-04 06:49:39 +00:00
Rafael Espindola 3d082fa507 Fix pr19645.
The fix itself is fairly simple: move getAccessVariant to MCValue so that we
replace the old weak expression evaluation with the far more general
EvaluateAsRelocatable.

This then requires that EvaluateAsRelocatable stop when it finds a non
trivial reference kind. And that in turn requires the ELF writer to look
harder for weak references.

Last but not least, this found a case where we were being bug by bug
compatible with gas and accepting an invalid input. I reported pr19647
to track it.

llvm-svn: 207920
2014-05-03 19:57:04 +00:00
Rafael Espindola 6c76d1d7df Handle _GLOBAL_OFFSET_TABLE_ in 64 bit mode.
With this MC is able to handle _GLOBAL_OFFSET_TABLE_ in 64 bit mode, which is
needed for medium and large code models.

This fixes pr19470.

llvm-svn: 206793
2014-04-21 21:15:45 +00:00
Kaelyn Takata f9d483128c Fix up MCFixup::getAccessVariant to handle unary expressions.
This allows correct relocations to be generated for a symbolic
address that is being adjusted by a negative constant. Since r204294,
such expressions have triggered undefined behavior when LLVM was built
without assertions.

Credit goes to Rafael for this patch; I'm submitting it on his behalf
as he is on vacation this week.

llvm-svn: 206192
2014-04-14 16:50:22 +00:00
Rafael Espindola 7fadc0ea7d Look through variables when computing relocations.
Given

bar = foo + 4
	.long bar

MC would eat the 4. GNU as includes it in the relocation. The rule seems to be
that a variable that defines a symbol is used in the relocation and one that
does not define a symbol is evaluated and the result included in the relocation.

Fixing this unfortunately required some other changes:

* Since the variable is now evaluated, it would prevent the ELF writer from
  noticing the weakref marker the elf streamer uses. This patch then replaces
  that with a VariantKind in MCSymbolRefExpr.

* Using VariantKind then requires us to look past other VariantKind to see

	.weakref	bar,foo
	call	bar@PLT

  doing this also fixes

	zed = foo +2
	call zed@PLT

  so that is a good thing.

* Looking past VariantKind means that the relocation selection has to use
  the fixup instead of the target.

This is a reboot of the previous fixes for MC. I will watch the sanitizer
buildbot and wait for a build before adding back the previous fixes.

llvm-svn: 204294
2014-03-20 02:12:01 +00:00
David Woodhouse adfc885997 [x86] Support R_386_PC8, R_386_PC16 and R_X86_64_PC8
llvm-svn: 198763
2014-01-08 12:58:40 +00:00
Tom Roeder 04d88fba3e This commit adds some (but not all) of the x86-64 relocations that are not
currently supported in the ELF object writer, along with a simple test case.

llvm-svn: 193709
2013-10-30 18:47:25 +00:00
David Majnemer 7b1cdb980b X86: Use R_X86_64_TPOFF64 for FK_Data_8
Summary:
LLVM would crash when trying to come up with a relocation type for
assembly like:
movabsq $V@TPOFF, %rax

Instead, we say the relocation type is R_X86_64_TPOFF64.

Fixes PR17274.

Reviewers: dblaikie, nrieck, rafael

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D1717

llvm-svn: 191163
2013-09-22 05:30:16 +00:00
David Blaikie c3ccdbe2bf Integrate Assembler: Support X86_64_DTPOFF64 relocations
llvm-svn: 185131
2013-06-28 04:24:32 +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 9bc32a96be print st_shndx with the correct number of bits.
llvm-svn: 136880
2011-08-04 15:50:13 +00:00
Rafael Espindola 9528995e3f print st_other with the correct number of bits.
llvm-svn: 136877
2011-08-04 15:38:19 +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 1b282e7e49 Another counter goes decimal.
llvm-svn: 136871
2011-08-04 14:27:46 +00:00
Rafael Espindola 65c559c5fb Change anther counter to decimal.
llvm-svn: 136870
2011-08-04 14:01:03 +00:00
Rafael Espindola cad9e7f094 Don't print a counter in hex.
llvm-svn: 136869
2011-08-04 13:39:15 +00:00
Rafael Espindola 69c67d3b18 Print all the bits in the addend.
llvm-svn: 136867
2011-08-04 13:00:24 +00:00
Eli Friedman 3846acc98e PR10370: Make sure we know how to relax push correctly on x86-64.
llvm-svn: 135303
2011-07-15 21:28:39 +00:00
Kevin Enderby 6aac575c9f Update MC/ELF/relocation.s with change to X86 PUSH64i8 in r134501.
llvm-svn: 134511
2011-07-06 17:55:20 +00:00
Rafael Espindola 0fc5e89c82 ADD64ri32 sign extends its argument, so we need to use a R_X86_64_32S.
Fixes PR9934.

We really need to start tblgening the relocation info :-(

llvm-svn: 131669
2011-05-19 20:32:34 +00:00
Rafael Espindola 9a1a34b105 Update tests
llvm-svn: 129116
2011-04-07 23:51:25 +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
Rafael Espindola 8bac423ddb Add support for lowercase variants.
llvm-svn: 124071
2011-01-23 16:11:25 +00:00
Rafael Espindola 3686473578 Fix PR8878.
llvm-svn: 122658
2011-01-01 19:05:35 +00:00
Rafael Espindola 8fc59a682f Handle reloc_riprel_4byte_movq_load. Should make the bots happy.
llvm-svn: 122579
2010-12-27 02:03:24 +00:00
Rafael Espindola 654cc4a81c Make pushq produce signed relocations.
llvm-svn: 122005
2010-12-16 22:50:01 +00:00
Benjamin Kramer e6840ef4b3 Fix some broken CHECK lines.
llvm-svn: 120332
2010-11-29 22:34:55 +00:00
Rafael Espindola 936ba3af28 Implement R_X86_64_DTPOFF32.
llvm-svn: 117548
2010-10-28 15:11:03 +00:00
Rafael Espindola 2dbec3f762 Implement TLSLD.
llvm-svn: 117547
2010-10-28 15:02:40 +00:00
Rafael Espindola 24c8b04d5f Implement R_X86_64_GOTTPOFF, R_X86_64_TLSGD and R_X86_64_TPOFF32.
llvm-svn: 117481
2010-10-27 20:28:07 +00:00
Jason W Kim e8b3711ae9 Fixing r116753 r116756 r116777
The failures in r116753 r116756 were caused by a python issue -
Python likes to append 'L' suffix to stringified numbers if the number
is larger than a machine int. Unfortunately, this causes a divergence of
behavior between 32 and 64 bit python versions.

I re-crafted elf-dump/common_dump to take care of these issues by:

1. always printing 0x (makes for easy sed/regex)
2. always print fixed length (exactly 2 + numBits/4 digits long)
   by mod ((2^numBits) - 1)
3. left-padded with '0'

There is a residual common routine that is also used by
macho-dump (dataToHex) , so I left the 'section_data' test values alone.

llvm-svn: 116823
2010-10-19 17:39:10 +00:00
Eric Christopher eac5e381cc Speculatively revert 116753 and 116756 to attempt to fix the bots.
llvm-svn: 116777
2010-10-19 00:19:49 +00:00
Jason W Kim eae048885d Changed elf-dump to output hex format by default.
Also updated tests. 

llvm-svn: 116753
2010-10-18 21:32:41 +00:00
Rafael Espindola f987d5ea1c Factor some logic into ShouldRelocOnSymbol. This simplifies the code and
fixes some cases where we were producing relocations with at symbol that
should use a section instead.

llvm-svn: 115194
2010-09-30 20:18:35 +00:00
Rafael Espindola 70d6e0e0ff Correctly produce R_X86_64_32 or R_X86_64_32S.
With this patch in

movq    $foo, foo(%rip)
foo:
.long   foo

We produce a R_X86_64_32S for the first relocation and R_X86_64_32 for the
second one.

llvm-svn: 115134
2010-09-30 03:11:42 +00:00
Rafael Espindola 32ab4558fe Produce a R_X86_64_32 when the value is >=0.
llvm-svn: 114339
2010-09-20 19:20:47 +00:00