Commit Graph

289 Commits

Author SHA1 Message Date
Rafael Espindola 2658554aec Add r224985 back with fixes.
The fixes are to note that AArch64 has additional restrictions on when local
relocations can be used. In particular, ld64 requires that relocations to
cstring/cfstrings use linker visible symbols.

Original message:

In an assembly expression like

bar:
  .long L0 + 1

the intended semantics is that bar will contain a pointer one byte past L0.

In sections that are merged by content (strings, 4 byte constants, etc), a
single position in the section doesn't give the linker enough information.
For example, it would not be able to tell a relocation must point to the
end of a string, since that would look just like the start of the next.

The solution used in ELF to use relocation with symbols if there is a non-zero
addend.

In MachO before this patch we would just keep all symbols in some sections.

This would miss some cases (only cstrings on x86_64 were implemented) and was
inefficient since most relocations have an addend of 0 and can be represented
without the symbol.

This patch implements the non-zero addend logic for MachO too.

llvm-svn: 226503
2015-01-19 21:11:14 +00:00
Rafael Espindola c569ac46eb Produce errors when an assignment expression would use a common symbol.
An assignment will produce a symbol with a given section and offset. There is
no way to represent something like "1 byte after a common symbol".

This matches the behavior of GNU as.

Part of PR22217.

llvm-svn: 226470
2015-01-19 17:30:24 +00:00
Rafael Espindola 7244bb3c17 Revert "Add r224985 back with two fixes."
This reverts commit r225644 while I debug a regression.

llvm-svn: 226022
2015-01-14 19:07:23 +00:00
Chandler Carruth d9903888d9 [cleanup] Re-sort all the #include lines in LLVM using
utils/sort_includes.py.

I clearly haven't done this in a while, so more changed than usual. This
even uncovered a missing include from the InstrProf library that I've
added. No functionality changed here, just mechanical cleanup of the
include order.

llvm-svn: 225974
2015-01-14 11:23:27 +00:00
Rafael Espindola d9c3e308f5 Add r224985 back with two fixes.
One is that AArch64 has additional restrictions on when local relocations can
be used. We have to take those into consideration when deciding to put a L
symbol in the symbol table or not.

The other is that ld64 requires the relocations to cstring to use linker
visible symbols on AArch64.

Thanks to Michael Zolotukhin for testing this!

Remove doesSectionRequireSymbols.

In an assembly expression like

bar:
.long L0 + 1

the intended semantics is that bar will contain a pointer one byte past L0.

In sections that are merged by content (strings, 4 byte constants, etc), a
single position in the section doesn't give the linker enough information.
For example, it would not be able to tell a relocation must point to the
end of a string, since that would look just like the start of the next.

The solution used in ELF to use relocation with symbols if there is a non-zero
addend.

In MachO before this patch we would just keep all symbols in some sections.

This would miss some cases (only cstrings on x86_64 were implemented) and was
inefficient since most relocations have an addend of 0 and can be represented
without the symbol.

This patch implements the non-zero addend logic for MachO too.

llvm-svn: 225644
2015-01-12 18:13:07 +00:00
Lang Hames 1e923ec122 Recommit r224935 with a fix for the ObjC++/AArch64 bug that that revision
introduced.

A test case for the bug was already committed in r225385.

Patch by Rafael Espindola.

llvm-svn: 225534
2015-01-09 18:55:42 +00:00
Lang Hames 66f755f84f Revert r224935 "Refactor duplicated code. No intended functionality change."
This is affecting the behavior of some ObjC++ / AArch64 test cases on Darwin.
Reverting to get the bots green while I track down the source of the changed
behavior.

llvm-svn: 225311
2015-01-06 23:04:36 +00:00
Lang Hames 04b37c4043 Revert r225048: It broke ObjC on AArch64.
I've filed http://llvm.org/PR22100 to track this issue.

llvm-svn: 225228
2015-01-06 00:54:32 +00:00
Rafael Espindola 54b435ec3c Add r224985 back with a fix.
The issues was that AArch64 has additional restrictions on when local
relocations can be used. We have to take those into consideration when
deciding to put a L symbol in the symbol table or not.

Original message:

Remove doesSectionRequireSymbols.

In an assembly expression like

bar:
.long L0 + 1

the intended semantics is that bar will contain a pointer one byte past L0.

In sections that are merged by content (strings, 4 byte constants, etc), a
single position in the section doesn't give the linker enough information.
For example, it would not be able to tell a relocation must point to the
end of a string, since that would look just like the start of the next.

The solution used in ELF to use relocation with symbols if there is a non-zero
addend.

In MachO before this patch we would just keep all symbols in some sections.

This would miss some cases (only cstrings on x86_64 were implemented) and was
inefficient since most relocations have an addend of 0 and can be represented
without the symbol.

This patch implements the non-zero addend logic for MachO too.

llvm-svn: 225048
2014-12-31 17:19:34 +00:00
Rafael Espindola d4da9040de Revert "Remove doesSectionRequireSymbols."
This reverts commit r224985.

I am investigating why it made an Apple bot unhappy.

llvm-svn: 225044
2014-12-31 16:06:48 +00:00
Rafael Espindola b22d5aa49a Remove doesSectionRequireSymbols.
In an assembly expression like

bar:
.long L0 + 1

the intended semantics is that bar will contain a pointer one byte past L0.

In sections that are merged by content (strings, 4 byte constants, etc), a
single position in the section doesn't give the linker enough information.
For example, it would not be able to tell a relocation must point to the
end of a string, since that would look just like the start of the next.

The solution used in ELF to use relocation with symbols if there is a non-zero
addend.

In MachO before this patch we would just keep all symbols in some sections.

This would miss some cases (only cstrings on x86_64 were implemented) and was
inefficient since most relocations have an addend of 0 and can be represented
without the symbol.

This patch implements the non-zero addend logic for MachO too.

llvm-svn: 224985
2014-12-30 13:13:27 +00:00
Rafael Espindola bed67f3adc Refactor duplicated code.
No intended functionality change.

llvm-svn: 224935
2014-12-29 15:18:31 +00:00
Derek Schuff 05fb735f3a [MC] Make bundle alignment mode setting idempotent and support nested bundles
Summary:
Currently an error is thrown if bundle alignment mode is set more than once
per module (either via the API or the .bundle_align_mode directive). This
change allows setting it multiple times as long as the alignment doesn't
change.

Also nested bundle_lock groups are currently not allowed. This change allows
them, with the effect that the group stays open until all nests are exited,
and if any of the bundle_lock directives has the align_to_end flag, the
group becomes align_to_end.

These changes make the bundle aligment simpler to use in the compiler, and
also better match the corresponding support in GNU as.

Reviewers: jvoung, eliben

Differential Revision: http://reviews.llvm.org/D5801

llvm-svn: 219811
2014-10-15 17:10:04 +00:00
Rafael Espindola 7b61ddfa6e Simplify handling of --noexecstack by using getNonexecutableStackSection.
llvm-svn: 219799
2014-10-15 16:12:52 +00:00
Benjamin Kramer 3e67db92bc MC: Bit pack MCSymbolData.
On x86_64 this brings it from 80 bytes to 64 bytes. Also make any member
variables private and clean up uses to go through the existing accessors.

NFC.

llvm-svn: 219573
2014-10-11 15:07:21 +00:00
Yaron Keren 559b47d051 Add and update reset() and doInitialization() methods to MC* and passes.
This enables reusing a PassManager instead of re-constructing it every time.

llvm-svn: 217948
2014-09-17 09:25:36 +00:00
Rafael Espindola adbe02435d Add a helper to MCExpr for when an expression is know to be absolute.
llvm-svn: 215713
2014-08-15 14:20:32 +00:00
Joerg Sonnenberger 752b91bd82 If available, pass down the Fixup object to EvaluateAsRelocatable.
At least on PowerPC, the interpretation of certain modifiers depends on
the context they appear in.

llvm-svn: 215310
2014-08-10 11:35:12 +00:00
David Majnemer 82cb0309e2 MC: make MCSymbolData::dump work on const objects
This just lets us dump a const MCSymbolData object, no functionality
changed.

llvm-svn: 212365
2014-07-05 00:39:52 +00:00
Rafael Espindola 83120cdf68 Avoid revocations when possible.
This is a small targeted fix for pr20119. The code needs quiet a bit of
refactoring and I added some FIXMEs about it, but I want to get the testcase
passing first.

llvm-svn: 212101
2014-07-01 14:34:30 +00:00
Weiming Zhao 58eb5ab326 Report error for non-zero data in .bss
User may initialize a var with non-zero value and specify .bss section.
E.g. : int a __attribute__((section(".bss"))) = 2;

This patch converts an assertion to error report for better user
experience.

Differential Revision: http://reviews.llvm.org/D4199

llvm-svn: 211455
2014-06-22 00:33:44 +00:00
Rafael Espindola 2aeac7a321 Move getBaseSymbol somewhere the COFF writer can use.
I will use it there in a second.

llvm-svn: 207761
2014-05-01 13:24:25 +00:00
Rafael Espindola fee224f942 Provide a version of getSymbolOffset that returns false on error.
This simplifies ELFObjectWriter::SymbolValue a bit more. This new version
will also be used in the COFF writer to fix pr19147.

llvm-svn: 207711
2014-04-30 21:51:13 +00:00
Rafael Espindola 5e096411dc Grammar fix.
Thanks to Saleem Abdulrasool for noticing it.

llvm-svn: 207643
2014-04-30 12:42:22 +00:00
Rafael Espindola bc03586bcc Simplify getSymbolOffset.
We can now use EvaluateAsValue to make it non recursive and remove some code
duplication.

llvm-svn: 207604
2014-04-30 03:06:06 +00:00
Benjamin Kramer b24592738e Another missing include for MSVC.
llvm-svn: 207596
2014-04-29 23:46:48 +00:00
Rafael Espindola b60c829a2a Centralize the handling of the thumb bit.
This patch centralizes the handling of the thumb bit around
MCStreamer::isThumbFunc and makes isThumbFunc handle aliases.

This fixes a corner case, but the main advantage is having just one
way to check if a MCSymbol is thumb or not. This should still be
refactored to be ARM only, but at least now it is just one predicate
that has to be refactored instead of 3 (isThumbFunc,
ELF_Other_ThumbFunc, and SF_ThumbFunc).

llvm-svn: 207522
2014-04-29 12:46:50 +00:00
Chandler Carruth f58e376d23 [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE
definition below all the header #include lines. This updates most of the
miscellaneous other lib/... directories. A few left though.

llvm-svn: 206845
2014-04-22 03:04:17 +00:00
Craig Topper bb694de649 [C++11] More 'nullptr' conversion or in some cases just using a boolean check instead of comparing to nullptr.
llvm-svn: 206129
2014-04-13 04:57:38 +00:00
David Blaikie 4d3b043542 Revert debug info compression support.
To support compression for debug_line and debug_frame a different
approach is required. To simplify review, revert the old implementation
and XFAIL the test case. New implementation to follow shortly.

Reverts r205059 and r204958.

llvm-svn: 205989
2014-04-10 21:53:47 +00:00
David Blaikie 857497b9c6 Simplify compression API by compressing into a SmallVector rather than a MemoryBuffer
This is the other half of r205676.

llvm-svn: 205677
2014-04-05 21:53:04 +00:00
Tim Northover 53d3251851 MachO: Add linker-optimisation hint framework to MC.
Another part of the ARM64 backend (so tests will be following soon).
This is currently used by the linker to relax adrp/ldr pairs into nops
where possible, though could well be more broadly applicable.

llvm-svn: 205084
2014-03-29 07:34:53 +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
David Blaikie 7400a97952 DebugInfo: Support for compressed debug info sections
1) When creating a .debug_* section and instead create a .zdebug_
   section.
2) When creating a fragment in a .zdebug_* section, make it a compressed
   fragment.
3) When computing the size of a compressed section, compress the data
   and use the size of the compressed data.
4) Emit the compressed bytes.

Also, check that only if a section has a compressed fragment, then that
is the only fragment in the section.

Assert-fail if the fragment's data is modified after it is compressed.

Initial review on llvm-commits by Eric Christopher and Rafael Espindola.

llvm-svn: 204958
2014-03-27 20:45:58 +00:00
Jim Grosbach 448334a738 Darwin: Add assembler directives to create version-min load commands.
Allow object files to be tagged with a version-min load command for iOS
or MacOSX.

Teach macho-dump to understand the version-min load commands for
testcases.

rdar://11337778

llvm-svn: 204190
2014-03-18 22:09:05 +00:00
Rafael Espindola 3d5d464df8 Try harder to evaluate expressions when printing assembly.
When printing assembly we don't have a Layout object, but we can still
try to fold some constants.

Testcase by Ulrich Weigand.

llvm-svn: 203677
2014-03-12 16:55:59 +00:00
David Woodhouse 9784cef38d Explictly pass MCSubtargetInfo to MCCodeEmitter::EncodeInstruction()
llvm-svn: 200348
2014-01-28 23:13:07 +00:00
Joerg Sonnenberger 808df6725f Fix indentation.
llvm-svn: 199118
2014-01-13 15:50:36 +00:00
Eric Christopher ed420bb5c3 Move assert above first use of variable that we'd be asserting on.
llvm-svn: 187899
2013-08-07 18:51:09 +00:00
Serge Pavlov 24a3ebb78d Use MCFillFragment for zero-initialized data.
It fixes PR16338 (ICE when compiling very large two-dimensional array).

Differential Revision: http://llvm-reviews.chandlerc.com/D1043

llvm-svn: 185080
2013-06-27 14:35:03 +00:00
Ulrich Weigand 32d725b80a [MC/DWARF] Support .debug_frame / .debug_line code alignment factors
I've been comparing the object file output of LLVM's integrated
assembler against the external assembler on PowerPC, and one
area where differences still remain are in DWARF sections.

In particular, the GNU assembler generates .debug_frame and
.debug_line sections using a code alignment factor of 4, since
all PowerPC instructions have size 4 and must be aligned to a
multiple of 4.  However, current MC code hard-codes a code
alignment factor of 1.

This patch changes this by adding a "minimum instruction alignment"
data element to MCAsmInfo and using this as code alignment factor.

This requires passing a MCContext into MCDwarfLineAddr::Encode
and MCDwarfLineAddr::EncodeAdvanceLoc.  Note that one caller,
MCDwarfLineAddr::Write, didn't actually have that information
available.  However, it turns out that this routine is in fact
never used in the whole code base, so the patch simply removes
it.  If it turns out to be needed again at a later time, it
could be re-added with an updated interface.

llvm-svn: 183834
2013-06-12 14:46:54 +00:00
Peter Collingbourne 2f495b93ee Add support for subsections to the ELF assembler. Fixes PR8717.
Differential Revision: http://llvm-reviews.chandlerc.com/D598

llvm-svn: 179725
2013-04-17 21:18:16 +00:00
Rafael Espindola 1b276c5cec Remove unused method and default values.
llvm-svn: 179124
2013-04-09 20:35:08 +00:00
David Blaikie b78e9e59ca Fix unnecessary removal of const through cast machinery
I have some uncommitted changes to the cast code that catch this sort of thing
at compile-time but I still need to do some other cleanup before I can enable
it.

llvm-svn: 174853
2013-02-11 01:16:51 +00:00
Derek Schuff 90aa1d8abe [MC] Bundle alignment: Invalidate relaxed fragments
Currently, when a fragment is relaxed, its size is modified, but its
offset is not (it gets laid out as a side effect of checking whether
it needs relaxation), then all subsequent fragments are invalidated
because their offsets need to change. When bundling is enabled,
relaxed fragments need to get laid out again, because the increase in
size may push it over a bundle boundary. So instead of only
invalidating subsequent fragments, also invalidate the fragment that
gets relaxed, which causes it to get laid out again.

This patch also fixes some trailing whitespace and fixes the
bundling-related debug output of MCFragments.

llvm-svn: 174401
2013-02-05 17:55:27 +00:00
Derek Schuff b76ec3bb5e [MC] bundle alignment: prevent padding instructions from crossing bundle boundaries
llvm-svn: 174067
2013-01-31 17:00:03 +00:00
Jack Carter 1bd90ff6cc This patch reworks how llvm targets set
and update ELF header e_flags.

Currently gathering information such as symbol, 
section and data is done by collecting it in an 
MCAssembler object. From MCAssembler and MCAsmLayout 
objects ELFObjectWriter::WriteObject() forms and 
streams out the ELF object file.

This patch just adds a few members to the MCAssember 
class to store and access the e_flag settings. It 
allows for runtime additions to the e_flag by 
assembler directives. The standalone assembler can 
get to MCAssembler from getParser().getStreamer().getAssembler().

This patch is the generic infrastructure and will be
followed by patches for ARM and Mips for their target 
specific use.

Contributer: Jack Carter
 
llvm-svn: 173882
2013-01-30 02:09:52 +00:00
Eli Bendersky cf6009b9c2 Optimize the memory usage of MC bundling, by creating a new type of fragment
into which we can emit single instructions without fixups (which is most
instructions). This is an optimization required because MCDataFragment
is prety large (240 bytes on x64), with no change in functionality.

For large programs, this reduces memory usage overhead required for bundling
by 40%.

To make the code as palatable as possible, the MCEncodedFragment interface was
further fragmented (no pun intended) and MCEncodedFragmentWithFixups is used
as the interface to work against when the user expects fixups. MCDataFragment
and MCRelaxableFragment implement this interface, while the new
MCCompactEncodedInstFragment implements MCEncodeFragment.

llvm-svn: 172572
2013-01-15 23:22:09 +00:00
Eli Bendersky 5277120dd0 Simplify the code a bit: MCRelaxableFragment doesn't need a separate getInstSize
method because getContents().size() already covers it. So computeFragmentSize
can use the generic MCEncodedFragment interface when querying both Data and
Relaxable fragments for contents sizes.

No change in functionality

llvm-svn: 171903
2013-01-08 22:05:10 +00:00
Eli Bendersky 0652dfd40c Rename statistic for instruction fragments -> relaxable
llvm-svn: 171872
2013-01-08 17:41:59 +00:00