Commit Graph

206 Commits

Author SHA1 Message Date
Rafael Espindola 6418856127 Simplify the processFixupValue interface. NFC.
llvm-svn: 306202
2017-06-24 05:22:28 +00:00
Rafael Espindola f351292141 Remove redundant argument.
llvm-svn: 306189
2017-06-24 00:26:57 +00:00
Rafael Espindola 801b42de31 ARM: move some logic from processFixupValue to applyFixup.
processFixupValue is called on every relaxation iteration. applyFixup
is only called once at the very end. applyFixup is then the correct
place to do last minute changes and value checks.

While here, do proper range checks again for fixup_arm_thumb_bl. We
used to do it, but dropped because of thumb2. We now do it again, but
use the thumb2 range.

llvm-svn: 306177
2017-06-23 22:52:36 +00:00
Rafael Espindola 88d9e37ec8 Use a MutableArrayRef. NFC.
llvm-svn: 305968
2017-06-21 23:06:53 +00:00
Rafael Espindola 3ac4c09daf clang-format a region.
It will make a followup patch easier to read.

llvm-svn: 305865
2017-06-20 22:53:29 +00:00
Zachary Turner 264b5d9e88 Move Object format code to lib/BinaryFormat.
This creates a new library called BinaryFormat that has all of
the headers from llvm/Support containing structure and layout
definitions for various types of binary formats like dwarf, coff,
elf, etc as well as the code for identifying a file from its
magic.

Differential Revision: https://reviews.llvm.org/D33843

llvm-svn: 304864
2017-06-07 03:48:56 +00:00
Chandler Carruth 6bda14b313 Sort the remaining #include lines in include/... and lib/....
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.

I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.

This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.

Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).

llvm-svn: 304787
2017-06-06 11:49:48 +00:00
Martin Storsjo 605b0466ea [AArch64] Fix a comment to match the code. NFC.
For the ELF case, the default/preferred form is the generic one, not
the short one as used for Apple - fix the comment to say so. Currently
it is a copy-paste typo.

Make the comments on the darwin default a bit more verbose.

Use enum names instead of literal 0/1 to further increase readability
and reduce fragility.

Differential Revision: https://reviews.llvm.org/D32963

llvm-svn: 302634
2017-05-10 10:51:32 +00:00
Joel Jones 6513405735 [AArch64] ILP32 Backend Relocation Support
Remove "_NC" suffix and semantics from TLSDESC_LD{64,32}_LO12 and
  TLSDESC_ADD_LO12 relocations
Rearrange ordering in AArch64.def to follow relocation encoding
Fix name:
  R_AARCH64_P32_LD64_GOT_LO12_NC => R_AARCH64_P32_LD32_GOT_LO12_NC
Add support for several "TLS", "TLSGD", and "TLSLD" relocations for
  ILP32
Fix return values from isNonILP32reloc
Add implementations for
  R_AARCH64_ADR_PREL_PG_HI21_NC, R_AARCH64_P32_LD32_GOT_LO12_NC,
  R_AARCH64_P32_TLSIE_LD32_GOTTPREL_LO12_NC,
  R_AARCH64_P32_TLSDESC_LD32_LO12, R_AARCH64_LD64_GOT_LO12_NC,
  *TLSLD_LDST128_DTPREL_LO12, *TLSLD_LDST128_DTPREL_LO12_NC,
  *TLSLE_LDST128_TPREL_LO12, *TLSLE_LDST128_TPREL_LO12_NC
Modify error messages to give name of equivalent relocation in the
  ABI not being used, along with better checking for non-existent
  requested relocations.
Added assembler support for "pg_hi21_nc"
Relocation definitions added without implementations:
  R_AARCH64_P32_TLSDESC_ADR_PREL21, R_AARCH64_P32_TLSGD_ADR_PREL21,
  R_AARCH64_P32_TLSGD_ADD_LO12_NC, R_AARCH64_P32_TLSLD_ADR_PREL21, 
  R_AARCH64_P32_TLSLD_ADR_PAGE21, R_AARCH64_P32_TLSLD_ADD_LO12_NC,
  R_AARCH64_P32_TLSLD_LD_PREL19, R_AARCH64_P32_TLSDESC_LD_PREL19,
  R_AARCH64_P32_TLSGD_ADR_PAGE21, R_AARCH64_P32_TLS_DTPREL,
  R_AARCH64_P32_TLS_DTPMOD, R_AARCH64_P32_TLS_TPREL,
  R_AARCH64_P32_TLSDESC
Fix encoding:
  R_AARCH64_P32_TLSDESC_ADR_PAGE21

Reviewers: Peter Smith

Patch by: Joel Jones (jjones@cavium.com)

Differential Revision: https://reviews.llvm.org/D32072

llvm-svn: 301980
2017-05-02 22:01:48 +00:00
Zachary Turner a0aae2757d Revert "Remove "_NC" suffix and semantics from TLSDESC_LD{64,32}_LO12 and"
This reverts commit c08155afc5d3230792da2ad30a046a8617735a73.

This is causing undefined symbol errors with some of the constants.

llvm-svn: 301944
2017-05-02 17:51:27 +00:00
Joel Jones 705103e523 Remove "_NC" suffix and semantics from TLSDESC_LD{64,32}_LO12 and
TLSDESC_ADD_LO12 relocations
Rearrange ordering in AArch64.def to follow relocation encoding
Fix name:
  R_AARCH64_P32_LD64_GOT_LO12_NC => R_AARCH64_P32_LD32_GOT_LO12_NC
Add support for several "TLS", "TLSGD", and "TLSLD" relocations for
  ILP32
Fix return values from isNonILP32reloc
Add implementations for
  R_AARCH64_ADR_PREL_PG_HI21_NC, R_AARCH64_P32_LD32_GOT_LO12_NC,
  R_AARCH64_P32_TLSIE_LD32_GOTTPREL_LO12_NC,
  R_AARCH64_P32_TLSDESC_LD32_LO12, R_AARCH64_LD64_GOT_LO12_NC,
  *TLSLD_LDST128_DTPREL_LO12, *TLSLD_LDST128_DTPREL_LO12_NC,
  *TLSLE_LDST128_TPREL_LO12, *TLSLE_LDST128_TPREL_LO12_NC
Modify error messages to give name of equivalent relocation in the
  ABI not being used, along with better checking for non-existent
  requested relocations.
Added assembler support for "pg_hi21_nc"
Relocation definitions added without implementations:
  R_AARCH64_P32_TLSDESC_ADR_PREL21, R_AARCH64_P32_TLSGD_ADR_PREL21,
  R_AARCH64_P32_TLSGD_ADD_LO12_NC, R_AARCH64_P32_TLSLD_ADR_PREL21, 
  R_AARCH64_P32_TLSLD_ADR_PAGE21, R_AARCH64_P32_TLSLD_ADD_LO12_NC,
  R_AARCH64_P32_TLSLD_LD_PREL19, R_AARCH64_P32_TLSDESC_LD_PREL19,
  R_AARCH64_P32_TLSGD_ADR_PAGE21, R_AARCH64_P32_TLS_DTPREL,
  R_AARCH64_P32_TLS_DTPMOD, R_AARCH64_P32_TLS_TPREL,
  R_AARCH64_P32_TLSDESC
Fix encoding:
  R_AARCH64_P32_TLSDESC_ADR_PAGE21

Reviewers: Peter Smith

Patch by: Joel Jones (jjones@cavium.com)

Differential Revision: https://reviews.llvm.org/D32072

llvm-svn: 301939
2017-05-02 17:14:31 +00:00
Tim Northover 100b7f6eae AArch64: lower "fence singlethread" to a pure compiler barrier.
Single-threaded fences aren't required to provide any synchronization with
other processing elements so there's no need for a DMB. They should still be a
barrier for compiler optimizations though.

llvm-svn: 300905
2017-04-20 21:57:45 +00:00
Konstantin Zhuravlyov dc77b2e960 Distinguish between code pointer size and DataLayout::getPointerSize() in DWARF info generation
llvm-svn: 300463
2017-04-17 17:41:25 +00:00
Andrew V. Tischenko 75745d0c3e This patch closes PR#32216: Better testing of schedule model instruction latencies/throughputs.
The details are here: https://reviews.llvm.org/D30941

llvm-svn: 300311
2017-04-14 07:44:23 +00:00
Alex Bradbury 866113c2ea Add MCContext argument to MCAsmBackend::applyFixup for error reporting
A number of backends (AArch64, MIPS, ARM) have been using
MCContext::reportError to report issues such as out-of-range fixup values in
their TgtAsmBackend. This is great, but because MCContext couldn't easily be
threaded through to the adjustFixupValue helper function from its usual
callsite (applyFixup), these backends ended up adding an MCContext* argument
and adding another call to applyFixup to processFixupValue. Adding an
MCContext parameter to applyFixup makes this unnecessary, and even better -
applyFixup can take a reference to MCContext rather than a potentially null
pointer.

Differential Revision: https://reviews.llvm.org/D30264

llvm-svn: 299529
2017-04-05 10:16:14 +00:00
Petr Hosek 9eb0a1e09b [AArch64][Fuchsia] Allow -mcmodel=kernel for --target=aarch64-fuchsia
This mode is just like -mcmodel=small except that it moves the
thread pointer from TPIDR_EL0 to TPIDR_EL1.

Patch by Roland McGrath.

Differential Revision: https://reviews.llvm.org/D31624

llvm-svn: 299462
2017-04-04 19:51:53 +00:00
Eugene Zelenko 939f6b0167 [AArch64] Fix some Include What You Use warnings; other minor fixes (NFC).
This is preparation to reduce MCExpr.h dependencies.

llvm-svn: 294053
2017-02-03 21:49:13 +00:00
Eugene Zelenko 049b017538 [AArch64, Lanai] Fix some Clang-tidy modernize and Include What You Use warnings; other minor fixes (NFC).
llvm-svn: 291197
2017-01-06 00:30:53 +00:00
Benjamin Kramer ffd3715d16 Give some helper classes/functions internal linkage. NFC.
llvm-svn: 287462
2016-11-19 20:44:26 +00:00
Daniel Sanders 72db2a390a Check that emitted instructions meet their predicates on all targets except ARM, Mips, and X86.
Summary:
* ARM is omitted from this patch because this check appears to expose bugs in this target.
* Mips is omitted from this patch because this check either detects bugs or deliberate
  emission of instructions that don't satisfy their predicates. One deliberate
  use is the SYNC instruction where the version with an operand is correctly
  defined as requiring MIPS32 while the version without an operand is defined
  as an alias of 'SYNC 0' and requires MIPS2.
* X86 is omitted from this patch because it doesn't use the tablegen-erated
  MCCodeEmitter infrastructure.

Patches for ARM and Mips will follow.

Depends on D25617

Reviewers: tstellarAMD, jmolloy

Subscribers: wdng, jmolloy, aemerson, rengolin, arsenm, jyknight, nemanjai, nhaehnle, tstellarAMD, llvm-commits

Differential Revision: https://reviews.llvm.org/D25618

llvm-svn: 287439
2016-11-19 13:05:44 +00:00
Joel Jones 504bf334b0 AArch64 ILP32 relocations for assembly and ELF
Summary:
Add relocations for AArch64 ILP32. Includes:
  - Addition of definitions for R_AARCH32_*
  - Definition of new -target-abi: ilp32
  - Definition of data layout string
  - Tests for added relocations. Not comprehensive, but matches
    existing tests for 64-bit. Renames "CHECK-OBJ" to "CHECK-OBJ-LP64".
  - Tests for llvm-readobj

Reviewers: zatrazz, peter.smith, echristo, t.p.northover

Subscribers: aemerson, rengolin, mehdi_amini

Differential Revision: https://reviews.llvm.org/D25159

llvm-svn: 284973
2016-10-24 13:37:13 +00:00
Diana Picus c93518db8c [AArch64] Allow label arithmetic with add/sub/cmp
Allow instructions such as 'cmp w0, #(end - start)' by folding the
expression into a constant. For ELF, we fold only if the symbols are in
the same section. For MachO, we fold if the expression contains only
symbols that are not linker visible.

Fixes https://llvm.org/bugs/show_bug.cgi?id=18920

Differential Revision: https://reviews.llvm.org/D23834

llvm-svn: 283862
2016-10-11 09:17:47 +00:00
Mehdi Amini f42454b94b Move the global variables representing each Target behind accessor function
This avoids "static initialization order fiasco"

Differential Revision: https://reviews.llvm.org/D25412

llvm-svn: 283702
2016-10-09 23:00:34 +00:00
Mehdi Amini 732afdd09a Turn cl::values() (for enum) from a vararg function to using C++ variadic template
The core of the change is supposed to be NFC, however it also fixes
what I believe was an undefined behavior when calling:

 va_start(ValueArgs, Desc);

with Desc being a StringRef.

Differential Revision: https://reviews.llvm.org/D25342

llvm-svn: 283671
2016-10-08 19:41:06 +00:00
Lei Liu 361615cfd0 AArch64: Set shift bit of TLSLE HI12 add instruction
Summary: AArch64 LLVM assembler emits add instruction without shift bit to calculate the higher 12-bit address of TLS variables in local exec model.  This generates wrong code sequence to access TLS variables with thread offset larger than 0x1000.

Reviewers: t.p.northover, peter.smith, rovka

Subscribers: salim.nasser, aemerson, llvm-commits, rengolin

Differential Revision: https://reviews.llvm.org/D24702

llvm-svn: 282661
2016-09-29 01:05:48 +00:00
Diana Picus 2a3f066349 Revert "AArch64: Set shift bit of TLSLE HI12 add instruction"
This reverts commit r282057 because it broke the buildbots - see e.g.
http://lab.llvm.org:8011/builders/clang-cmake-aarch64-42vma/builds/12063

llvm-svn: 282058
2016-09-21 08:24:41 +00:00
Lei Liu 6c87f23526 AArch64: Set shift bit of TLSLE HI12 add instruction
Summary: AArch64 LLVM assembler emits add instruction without shift bit to calculate the higher 12-bit address of TLS variables in local exec model.  This generates wrong code sequence to access TLS variables with thread offset larger than 0x1000.

Reviewers: t.p.northover, peter.smith, rovka

Subscribers: salim.nasser, aemerson, llvm-commits, rengolin

Differential Revision: https://reviews.llvm.org/D24702

llvm-svn: 282057
2016-09-21 07:41:41 +00:00
Diana Picus a53660e4a3 [AArch64] Fix encoding for lsl #12 in add/sub immediates
Whenever an add/sub immediate needs a fixup, we set that immediate field to zero,
which is correct, but we also set the shift bits to zero, which is not true for
instructions that use lsl #12. This patch makes sure that if lsl #12 was used,
it will appear in the encoding of the instruction.

Differential Revision: https://reviews.llvm.org/D23930

llvm-svn: 281898
2016-09-19 11:10:18 +00:00
Reid Kleckner a5b1eef846 [MC] Move .cv_loc management logic out of MCContext
MCContext already has many tasks, and separating CodeView out from it is
probably a good idea. The .cv_loc tracking was modelled on the DWARF
tracking which lived directly in MCContext.

Removes the inclusion of MCCodeView.h from MCContext.h, so now there are
only 10 build actions while I hack on CodeView support instead of 265.

llvm-svn: 279847
2016-08-26 17:58:37 +00:00
Mike Aizatsky f4fdb5ddf3 [AArch64] Registering default MCInstrAnalysis
Even in this form it is useful: it can detect branch instructions.

https://github.com/google/sanitizers/issues/706

Subscribers: aemerson, rengolin

Differential Revision: https://reviews.llvm.org/D23426

llvm-svn: 278560
2016-08-12 20:28:05 +00:00
Joel Jones 373d7d30dd MC] Provide an MCTargetOptions to implementors of MCAsmBackendCtorTy, NFC
Some targets, notably AArch64 for ILP32, have different relocation encodings
based upon the ABI. This is an enabling change, so a future patch can use the
ABIName from MCTargetOptions to chose which relocations to use. Tested using
check-llvm.

The corresponding change to clang is in: http://reviews.llvm.org/D16538

Patch by: Joel Jones

Differential Revision: https://reviews.llvm.org/D16213

llvm-svn: 276654
2016-07-25 17:18:28 +00:00
Nirav Dave 8603062ee4 Fix branch relaxation in 16-bit mode.
Thread through MCSubtargetInfo to relaxInstruction function allowing relaxation
to generate jumps with 16-bit sized immediates in 16-bit mode.

This fixes PR22097.

Reviewers: dwmw2, tstellarAMD, craig.topper, jyknight

Subscribers: jfb, arsenm, jyknight, llvm-commits, dsanders

Differential Revision: http://reviews.llvm.org/D20830

llvm-svn: 275068
2016-07-11 14:23:53 +00:00
Rafael Espindola d86e8bb0ed Delete MCCodeGenInfo.
MC doesn't really care about CodeGen stuff, so this was just
complicating target initialization.

llvm-svn: 274258
2016-06-30 18:25:11 +00:00
Rafael Espindola 2b7fef681f Delete more dead code.
Found by gcc 6.

llvm-svn: 273402
2016-06-22 12:44:16 +00:00
Tim Northover daa1c018b0 AArch64: allow MOV (imm) alias to be printed
The backend has been around for years, it's pretty ridiculous that we can't
even use the preferred form for printing "MOV" aliases. Unfortunately, TableGen
can't handle the complex predicates when printing so it's a bunch of nasty C++.
Oh well.

llvm-svn: 272865
2016-06-16 01:42:25 +00:00
Rafael Espindola 8c34dd8257 Delete Reloc::Default.
Having an enum member named Default is quite confusing: Is it distinct
from the others?

This patch removes that member and instead uses Optional<Reloc> in
places where we have a user input that still hasn't been maped to the
default value, which is now clear has no be one of the remaining 3
options.

llvm-svn: 269988
2016-05-18 22:04:49 +00:00
Mehdi Amini b550cb1750 [NFC] Header cleanup
Removed some unused headers, replaced some headers with forward class declarations.

Found using simple scripts like this one:
clear && ack --cpp -l '#include "llvm/ADT/IndexedMap.h"' | xargs grep -L 'IndexedMap[<]' | xargs grep -n --color=auto 'IndexedMap'

Patch by Eugene Kosov <claprix@yandex.ru>

Differential Revision: http://reviews.llvm.org/D19219

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266595
2016-04-18 09:17:29 +00:00
Oliver Stannard a5520b02a5 [AArch64] Better errors for out-of-range fixups
When a fixup that can be resolved by the assembler is out of range, we should
report an error in the source, rather than crashing.

Differential Revision: http://reviews.llvm.org/D18402

llvm-svn: 265120
2016-04-01 09:14:50 +00:00
Oliver Stannard aa77b1e025 [AArch64] Replace some uses of report_fatal_error with reportError in AArch64 ELF object writer
If we can't handle a relocation type, report it as an error in the source,
rather than asserting. I've added a more descriptive message and a test for the
only cases of this that I've been able to trigger.

Differential Revision: http://reviews.llvm.org/D18388

llvm-svn: 264156
2016-03-23 13:45:03 +00:00
Tim Northover 87442c1133 AArch64: rename compact unwind forms back to UNWIND_ARM64_*. NFC.
Looks like the global rename last year was a bit over-zealous. These things
really are referred to with ARM64 elsewhere (ld64, libunwind, ...).

llvm-svn: 261698
2016-02-23 21:49:05 +00:00
Chris Bieneman e49730d4ba Remove autoconf support
Summary:
This patch is provided in preparation for removing autoconf on 1/26. The proposal to remove autoconf on 1/26 was discussed on the llvm-dev thread here: http://lists.llvm.org/pipermail/llvm-dev/2016-January/093875.html

"I felt a great disturbance in the [build system], as if millions of [makefiles] suddenly cried out in terror and were suddenly silenced. I fear something [amazing] has happened."
- Obi Wan Kenobi

Reviewers: chandlerc, grosbach, bob.wilson, tstellarAMD, echristo, whitequark

Subscribers: chfast, simoncook, emaste, jholewinski, tberghammer, jfb, danalbert, srhines, arsenm, dschuff, jyknight, dsanders, joker.eph, llvm-commits

Differential Revision: http://reviews.llvm.org/D16471

llvm-svn: 258861
2016-01-26 21:29:08 +00:00
Keith Walker 8c44bf1b89 Write AArch64 big endian data fixup entries as BE.
There was support for writing the AArch64 big endian data fixup entries in
the .eh_frame section in BE.    This is changed to write all such fixup
entries in BE with no restriction on the section.  This is similar to
the existing support for fixup entries for ARM.

A test is added to check the length field in the .debug_line section as
this is an example of where such a fixup occurs.

Differential Revision: http://reviews.llvm.org/D16064

llvm-svn: 258320
2016-01-20 15:59:14 +00:00
Oliver Stannard f7696f8267 [AArch64] Fix two bugs in the .inst directive
The AArch64 .inst directive was implemented using EmitIntValue, which resulted
in both $x and $d (code and data) mapping symbols being emitted at the same
address. This fixes it to only emit the $x mapping symbol.

EmitIntValue also emits the value in big-endian order when targeting big-endian
systems, but instructions are always emitted in little-endian order for
AArch64.

Differential Revision: http://reviews.llvm.org/D16349

llvm-svn: 258308
2016-01-20 12:54:31 +00:00
Rafael Espindola 8340f94df1 Convert a few assert failures into proper errors.
Fixes PR25944.

llvm-svn: 257697
2016-01-13 22:56:57 +00:00
Oliver Stannard b25914e03f [AArch64] Add ARMv8.2-A FP16 scalar instructions
ARMv8.2-A adds 16-bit floating point versions of all existing VFP
floating-point instructions. This is an optional extension, so all of
these instructions require the FeatureFullFP16 subtarget feature.

Most of these instructions are the same as the 32- and 64-bit versions,
but with the type field (bits 23-22) set to 0b11. Previously the top bit
of the size field was always 0, so the instruction classes only provided
a 1-bit size field, which I have widened to 2 bits.

Differential Revision: http://reviews.llvm.org/D15014

llvm-svn: 254198
2015-11-27 13:04:48 +00:00
Oliver Stannard 9be59af3ab [Assembler] Make fatal assembler errors non-fatal
Currently, if the assembler encounters an error after parsing (such as an
out-of-range fixup), it reports this as a fatal error, and so stops after the
first error. However, for most of these there is an obvious way to recover
after emitting the error, such as emitting the fixup with a value of zero. This
means that we can report on all of the errors in a file, not just the first
one. MCContext::reportError records the fact that an error was encountered, so
we won't actually emit an object file with the incorrect contents.

Differential Revision: http://reviews.llvm.org/D14717

llvm-svn: 253328
2015-11-17 10:00:43 +00:00
Oliver Stannard 9327a7575b [ARM,AArch64] Store source location of asm constant pool entries
Storing the source location of the expression that created a constant pool
entry allows us to emit better error messages if we later discover that the
expression cannot be represented by a relocation.

Differential Revision: http://reviews.llvm.org/D14646

llvm-svn: 253220
2015-11-16 16:25:47 +00:00
Oliver Stannard 09be060606 [ARM,AArch64] Store source location for values in assembly files
The MCValue class can store a SMLoc to allow better error messages to be
emitted if an error is detected after parsing. The ARM and AArch64 assembly
parsers were not setting this, so error messages did not have source
information.

Differential Revision: http://reviews.llvm.org/D14645

llvm-svn: 253219
2015-11-16 16:22:47 +00:00
Ahmed Bougacha 4a85643907 [MC] Use LShr for constant evaluation of ">>" on non-arm64 darwin.
Follow-up to r235963: this matches other assemblers and is less
unexpected (e.g. PR23227).

llvm-svn: 252681
2015-11-11 00:51:36 +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