Commit Graph

128 Commits

Author SHA1 Message Date
David Majnemer 2cc4bc77bf MC, COFF: Use relocations for function references inside the section
Referencing one symbol from another in the same section does not
generally require a relocation.  However, the MS linker has a feature
called /INCREMENTAL which enables incremental links.  It achieves this
by creating thunks to the actual function and redirecting all
relocations to point to the thunk.

This breaks down with the old scheme if you have a function which
references, say, itself.  On x86_64, we would use %rip relative
addressing to reference the start of the function from out current
position.  This would lead to miscompiles because other references might
reference the thunk instead, breaking function pointer equality.

This fixes PR21520.

llvm-svn: 221678
2014-11-11 08:43:57 +00:00
David Majnemer 3416b48980 MC, COFF: Make bigobj test compatible with python3
No functionality change intended.

llvm-svn: 219739
2014-10-14 22:35:11 +00:00
David Majnemer 0b011b337f MC: Rewrite bigobj test in python
This makes the test easier to work with.  No functionality change
intended.

llvm-svn: 219737
2014-10-14 22:26:49 +00:00
David Majnemer 5fdfa70a1f Add a test for writing COFF BigObj
llvm-svn: 219729
2014-10-14 21:47:53 +00:00
Timur Iskhodzhanov 5fcaeebb72 Fix COFF section index relocation should be 16 bits, not 32
Original patch by Andrey Guskov!
http://reviews.llvm.org/D5651

llvm-svn: 219327
2014-10-08 18:01:49 +00:00
David Majnemer d7586046ee COFF: Don't oversize COMMON symbols when targeting BFD ld
COFF normally doesn't allow us to describe the alignment of COMMON
symbols.

It turns out that most linkers use the symbol size as a hint as to how
aligned the symbol should be.

However the BFD folks have added a .drectve command, which we
now support as of r219229, that allows us to specify the alignment
precisely.  With this in mind, stop rounding sizes up.

llvm-svn: 219281
2014-10-08 06:38:53 +00:00
Saleem Abdulrasool 64d491e488 MC: add support for -aligncomm GNU extension
The GNU linker supports an -aligncomm directive that allows for power-of-2
alignment of common data.  Add support to emit this directive.

llvm-svn: 219229
2014-10-07 19:37:57 +00:00
Hans Wennborg f26bfc1671 WinCOFFObjectWriter: optimize the string table for common suffices
This is a follow-up from r207670 which did the same for ELF.

Differential Revision: http://reviews.llvm.org/D5530

llvm-svn: 218636
2014-09-29 22:43:20 +00:00
Reid Kleckner 81782f0cb8 MC: Use @IMGREL instead of @IMGREL32, which we can't parse
Nico Rieck added support for this 32-bit COFF relocation some time ago
for Win64 stuff. It appears that as an oversight, the assembly output
used "foo"@IMGREL32 instead of "foo"@IMGREL, which is what we can parse.

Sadly, there were actually tests that took in IMGREL and put out
IMGREL32, and we didn't notice the inconsistency. Oh well. Now LLVM can
assemble it's own output with slightly more fidelity.

llvm-svn: 218437
2014-09-25 02:09:18 +00:00
David Majnemer 597be2ded6 MC: ReadOnlyWithRel section kinds should map to rdata in COFF
Don't consider ReadOnlyWithRel as a writable section in COFF, they
really belong in .rdata.

llvm-svn: 218268
2014-09-22 20:39:23 +00:00
David Majnemer 48227a3759 MC: Support aligned COMMON symbols for COFF
link.exe:
Fuzz testing has shown that COMMON symbols with size > 32 will always
have an alignment of at least 32 and all symbols with size < 32 will
have an alignment of at least the largest power of 2 less than the size
of the symbol.

binutils:
The BFD linker essentially work like the link.exe behavior but with
alignment 4 instead of 32.  The BFD linker also supports an extension to
COFF which adds an -aligncomm argument to the .drectve section which
permits specifying a precise alignment for a variable but MC currently
doesn't support editing .drectve in this way.

With all of this in mind, we decide to play a little trick: we can
ensure that the alignment will be respected by bumping the size of the
global to it's alignment.

llvm-svn: 218201
2014-09-21 09:18:07 +00:00
David Majnemer fb83977538 Update tests which broke from r218189
llvm-svn: 218191
2014-09-20 21:18:43 +00:00
David Majnemer 7d0dc3ef18 MC: Fix MCSectionCOFF::PrintSwitchToSection
We had a few bugs:
- We were considering the GVKind instead of just looking at the section
  characteristics
- We would never print out 'y' when a section was meant to be unreadable
- We would never print out 's' when a section was meant to be shared
- We translated IMAGE_SCN_MEM_DISCARDABLE to 'n' when it should've meant
  IMAGE_SCN_LNK_REMOVE

llvm-svn: 218189
2014-09-20 20:40:50 +00:00
David Majnemer b8dbebb31c MC: Treat ReadOnlyWithRel and ReadOnlyWithRelLocal as ReadOnly for COFF
A problem with our old behavior becomes observable under x86-64 COFF
when we need a read-only GV which has an initializer which is referenced
using a relocation: we would mark the section as writable.  Marking the
section as writable interferes with section merging.

This fixes PR21009.

llvm-svn: 218179
2014-09-20 07:31:46 +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
Reid Kleckner 7c4059eb89 MC Win64: Put unwind info for COMDAT code into the same COMDAT group
Summary:
This fixes a long standing issue where we would emit many little .text
sections and only one .pdata and .xdata section. Now we generate one
.pdata / .xdata pair per .text section and associate them correctly.

Fixes PR19667.

Reviewers: majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5181

llvm-svn: 217176
2014-09-04 17:42:03 +00:00
Reid Kleckner 21aedc4b83 MC: Diagnose an unexpected token in COFF .section instead of asserting
This can easily arise when trying to assemble and ELF style .section
directive for a COFF object file.

llvm-svn: 215373
2014-08-11 18:34:43 +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
Ehsan Akhgari 342595f832 [ms-coff] Add a test for proper handling of full Windows path names in the .drectve section
Summary: This test ensures that we can correctly specify a full Windows path to the clang ASAN runtime libraries.  This is in preparation to fix PR20246.

Reviewers: rafael

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D4427

llvm-svn: 212580
2014-07-09 00:40:50 +00:00
Reid Kleckner b5dd9452b4 Fix .seh_stackalloc 0
seh_stackalloc 0 is not representable in Win64 SEH info, so emitting it
is a bug.

Reviewers: rnk

Differential Revision: http://reviews.llvm.org/D4334

Patch by Vadim Chugunov!

llvm-svn: 212081
2014-07-01 00:42:47 +00:00
David Majnemer c57d038240 MC: Fix associative sections on COFF
COFF sections in MC were represented by a tuple of section-name and
COMDAT-name.  This is not sufficient to represent a .text section
associated with another .text section; we need a way to distinguish
between the key section and the one marked associative.

llvm-svn: 211913
2014-06-27 17:19:44 +00:00
Kevin Enderby 4fc2edb023 Change the default input for llvm-nm to be a.out instead of standard input
to match llvm-size and other UNIX systems for their nm(1).

Tweak test cases that used llvm-nm with standard input to add a "-" to
indicate that and add a test case to check the default of a.out for llvm-nm.

llvm-svn: 211529
2014-06-23 20:27:53 +00:00
Alp Toker d3d017cf00 Reduce verbiage of lit.local.cfg files
We can just split targets_to_build in one place and make it immutable.

llvm-svn: 210496
2014-06-09 22:42:55 +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 0766ae08e5 Fix a few issues with comdat handling on COFF.
* Section association cannot use just the section name as many
sections can have the same name. With this patch, the comdat symbol in
an assoc section is interpreted to mean a symbol in the associated
section and the mapping is discovered from it.

* Comdat symbols were not being set correctly. Instead we were getting
whatever was output first for that section.

A consequence is that associative sections now must use .section to
set the association. Using .linkonce would not work since it is not
possible to change a sections comdat symbol (it is used to decide if
we should create a new section or reuse an existing one).

This includes r210298, which was reverted because it was asserting
on an associated section having the same comdat as the associated
section.

llvm-svn: 210367
2014-06-06 19:26:12 +00:00
Timur Iskhodzhanov 460cf8891b Revert r210298 'Correctly set the comdat symbol on COFF' as it asserts on Windows
llvm-svn: 210317
2014-06-06 08:18:18 +00:00
Rafael Espindola 942f4bc488 Correctly set the comdat symbol on COFF.
We extended the .section syntax to allow multiple sections with the
same name but different comdats, but currently we don't make sure that
the output section has that comdat symbol.

That happens to work with the code llc produces currently because it looks like

.section secName, "dr", one_only, "COMDATSym"
.globl COMDATSym
COMDATSym:
....

but that is not very friendly to anyone coding in assembly or even to
llc once we get comdat support in the IR.

This patch changes the coff object writer to make sure the comdat symbol is
output just after the section symbol, as required by the coff spec.

llvm-svn: 210298
2014-06-05 23:09:25 +00:00
Hans Wennborg 8e873329a1 Don't emit structors for available_externally globals (PR19933)
We would previously assert here when trying to figure out the section
for the global.

This makes us handle the situation more gracefully since the IR isn't
malformed.

Differential Revision: http://reviews.llvm.org/D4022

llvm-svn: 210215
2014-06-04 21:04:54 +00:00
Saleem Abdulrasool a4f1ec043c MC: remove unnecessary restriction on tests
Rafael correctly pointed out that the restriction is unnecessary.  Although the
tests are intended to ensure that we dont abort due to an assertion, running the
tests in all modes is better since it also ensures that we dont crash without
assertions.  Always run these tests to ensure that we can handle invalid input
correctly.

llvm-svn: 209496
2014-05-23 02:56:51 +00:00
Saleem Abdulrasool 6663f8f2c0 MC: formalise some assertions into proper errors
Now that clang can be used as an assembler via the IAS, invalid assembler inputs
would cause the assertions to trigger.  Although we cannot recover from the
errors here, nor provide caret diagnostics, attempt to handle them slightly more
gracefully by reporting a fatal error.

llvm-svn: 209387
2014-05-22 02:18:10 +00:00
Saleem Abdulrasool ec8c2db283 MC: mark COFF .drectve section as REMOVE
The .drectve section should be marked as IMAGE_SCN_LNK_REMOVE.  This matches what
the MSVC toolchain does and accurately reflects that this section should not be
emitted into the final binary.  This section is merely information for the
linker, comprising of additional linker directives.

llvm-svn: 209273
2014-05-21 05:15:01 +00:00
Reid Kleckner fceb76f5f9 Add comdat key field to llvm.global_ctors and llvm.global_dtors
This allows us to put dynamic initializers for weak data into the same
comdat group as the data being initialized.  This is necessary for MSVC
ABI compatibility.  Once we have comdats for guard variables, we can use
the combination to help GlobalOpt fire more often for weak data with
guarded initialization on other platforms.

Reviewers: nlewycky

Differential Revision: http://reviews.llvm.org/D3499

llvm-svn: 209015
2014-05-16 20:39:27 +00:00
Saleem Abdulrasool 734bca04ff MC: place .file records into the correct section
.file records are supposed to have a section identifier of 65534
(IMAGE_SCN_DEBUG) rather than 0.  This is spelt out clearly within the PE/COFF
specification.  Fix this minor oversight with the implementation for support for
.file records.

llvm-svn: 207851
2014-05-02 17:45:24 +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
Rafael Espindola 575f79a409 Compute the correct section for zed = foo + 1 in COFF.
This fixes pr19147.

There are a few more related issues to fix, but the testcase in the bug now
passes.

llvm-svn: 207763
2014-05-01 13:37:57 +00:00
Rafael Espindola ff68cb7f4c Start fixing pr19147.
This makes the coff writer compute the correct symbol value for the test in
pr19147. The section is still incorrect, that will be fixed in a followup patch.

llvm-svn: 207728
2014-05-01 00:10:17 +00:00
Saleem Abdulrasool 7c34b6dd65 MC: duplicate .file test for WoA (SVN r207341)
Since the COFF tests are dependent on X86, duplicate the test for ARM.  Use the
default check prefix.

llvm-svn: 207365
2014-04-27 16:10:57 +00:00
Saleem Abdulrasool 710f944830 COFF: move ARM COFF test to ARM directory
The COFF tests all assume X86.  Just move the new COFF tests under ARM to
appease the build bots.

llvm-svn: 207346
2014-04-27 04:29:32 +00:00
Saleem Abdulrasool 84b952b677 Add WoA object file emission support
Introduce support for WoA PE/COFF object file emission from LLVM.  Add the new
target specific PE/COFF Streamer (ARMWinCOFFStreamer) that handles the ARM
specific behaviour of PE/COFF object emission.  ARM exception information is not
yet emitted and is a TODO item.

The ARM specific object writer (ARMWinCOFFObjectWriter) handles the ARM specific
relocation handling in conjunction with the WinCOFFObjectWriter in the MC layer.
The MC layer needs to be updated to deal with the relocation adjustments.
Branch relocations are adjusted by 4 bytes (unlikely their ELF counterparts).

Minor tweaks to switch multiple conditional checks into equivalent switch
statements.  The ObjectFileInfo is updated to relax the object file setup for
Windows COFF.  Move the architecture checks into an assertion.  Windows COFF is
currently only supported on x86, x86_64, and ARM (thumb).  Rather than
defaulting to ELF, we will refuse to generate an object file.  This is better
though as you do not get an (arbitrary) object file which is different from the
request.

llvm-svn: 207345
2014-04-27 03:48:22 +00:00
Saleem Abdulrasool b6d051c4f0 MC: disable test on thumbv7-windows
This is dependent on changes that are not fully ready to be merged yet (WoA
object file emission).  The test can be re-enabled for that target later.

llvm-svn: 207038
2014-04-23 21:55:18 +00:00
Saleem Abdulrasool 9e6a524551 MC: move test from Generic to COFF
This is a COFF specific test, move it to COFF to fix the Hexagon buildbots.

llvm-svn: 207030
2014-04-23 21:41:07 +00:00
Saleem Abdulrasool 11049a0fef MC: honour IMAGE_SCN_CNT_INITIALIZED_DATA
Emit the flag to indicate to the assembler that a section contains data if there
is pre-populated data present.

llvm-svn: 207028
2014-04-23 21:29:34 +00:00
Saleem Abdulrasool 057094c6f6 COFF: fix an off by one error
Adjust the tests to validate the number of auxiliary entries used to store the
filename.

Thanks to majnemer's sharp eye for catching the missing - 1 in the round up
calculation.

llvm-svn: 206359
2014-04-16 06:22:53 +00:00
Saleem Abdulrasool a2bf05aa2f COFF: add support for .file symbols
Add support for emitting .file records.  This is mostly a quality of
implementation change (more complete support for COFF file emission) that was
noticed while working on COFF file emission for Windows on ARM.

A .file record is emitted as a symbol with storage class FILE (103) and the name
".file".  A series of auxiliary format 4 records follow which contain the file
name.  The filename is stored as an ANSI string and is padded with NULL if the
length is not a multiple of COFF::SymbolSize (18).

llvm-svn: 206355
2014-04-16 04:15:32 +00:00
David Majnemer a9bdb32f04 WinCOFF: Emit common symbols as specified in the COFF spec
Summary:
Local common symbols were properly inserted into the .bss section.
However, putting external common symbols in the .bss section would give
them a strong definition.

Instead, encode them as undefined, external symbols who's symbol value
is equivalent to their size.

Reviewers: Bigcheese, rafael, rnk

CC: llvm-commits

Differential Revision: http://reviews.llvm.org/D3324

llvm-svn: 205811
2014-04-08 22:33:40 +00:00
Rui Ueyama cec949af13 Object/COFF: change data type of SymbolNumber from int16 to uint16.
Microsoft PE/COFF Spec clearly states that the field is of signed interger
type. However, in reality, it's unsigned. If cl.exe needs to create a large
number of sections for COMDAT sections, it will just create more than 32768
sections. Handling large section number as negative number is not correct.
I think this is a spec bug.

Differential Revision: http://llvm-reviews.chandlerc.com/D3088

llvm-svn: 203986
2014-03-15 00:04:08 +00:00
Alp Toker 70b36995e4 Fix typos
llvm-svn: 202107
2014-02-25 04:21:15 +00:00
Nico Rieck 9d2c15eff7 MC: Support COFF string tables larger than 10MB
Offsets past the range of single-slash encoding are encoded as base64,
padded to 6 characters, and prefixed with two slashes. This encoding is
undocumented but used by MSVC.

llvm-svn: 201940
2014-02-22 16:12:20 +00:00
Timur Iskhodzhanov 3e4ac4eeca Fix PR18381 - print a minimal diagnostic rather than assert on unresolved .secidx target
llvm-svn: 200490
2014-01-30 21:13:05 +00:00