Commit Graph

82 Commits

Author SHA1 Message Date
Benjamin Kramer d3f4c05aea Move instances of std::function.
Or replace with llvm::function_ref if it's never stored. NFC intended.

llvm-svn: 272513
2016-06-12 16:13:55 +00:00
Daniel Sanders cda908a0b6 [mips][ias] EF_MIPS_MICROMIPS should iff microMIPS code was emitted.
Summary:
This fixes PR27682. Additionally, '.set micromips' by itself is not sufficient
to raise the EF_MIPS_MICROMIPS flag. It is also necessary to emit a microMIPS
instruction. This has also been fixed.

Reviewers: sdardis, vkalintiris, rafael

Subscribers: rafael, dsanders, sdardis, llvm-commits

Differential Revision: http://reviews.llvm.org/D20214

llvm-svn: 269639
2016-05-16 09:10:13 +00:00
Daniel Sanders 241c67989b [mips][ias] Fix O32 .cprestore directive when inside .set noat region and offset is in range.
Summary:
This expands on r269179 to fix an additional case that was not covered by our
tests. The assembler temporary is not needed when the .cprestore offset fits
inside a simm16 and it is not an error to use it inside a '.set noat' in this
case.

Reviewers: emaste, seanbruno, sdardis

Subscribers: dsanders, sdardis, llvm-commits

Differential Revision: http://reviews.llvm.org/D20199

llvm-svn: 269295
2016-05-12 14:01:50 +00:00
Daniel Sanders 10e6cefd82 [mips][ias] Fix missing header that should have been in r269179
llvm-svn: 269180
2016-05-11 13:04:22 +00:00
Daniel Sanders df8510d4fa [mips][ias] Fix N32 and N64 .cprestore directive when inside .set noat region.
Summary:
r268058 unintentionally made the retrieval of the current assembler temporary
unconditional. This was fine for the existing tests but it broke the cases
where the assembler temporary is not needed (N32/N64 or not PIC) and is
unavailable due to a '.set noat' directive.

This fixes FreeBSD's libc.

Reviewers: emaste, sdardis, seanbruno

Subscribers: dsanders, emaste, sdardis, llvm-commits

Differential Revision: http://reviews.llvm.org/D20093

llvm-svn: 269179
2016-05-11 12:48:19 +00:00
Daniel Sanders 8de3d3cad6 [mips] Fix inconsistent .cprestore behaviour between direct object emission and assembling.
Summary:
Direct object emission has an initialization order problem where an
InitMCObjectFile is called after MipsTargetELFStreamer determines whether
PIC is enabled by default or not. There doesn't seem to be point that
initializes all cases so split the responsibility between
MipsTargetELFStreamer and MipsAsmPrinter.

Reviewers: sdardis

Subscribers: dsanders, llvm-commits, sdardis

Differential Revision: http://reviews.llvm.org/D19728

llvm-svn: 268737
2016-05-06 14:37:24 +00:00
Daniel Sanders 7225cd52e7 [mips][ias] Move createCpRestoreMemOp to MipsTargetStreamer. NFC.
Summary:
This removes the temporary call to isIntegratedAssemblerRequired() which was
added recently. It's effect is now acheived directly in the MipsTargetStreamer
hierarchy.

Reviewers: sdardis

Subscribers: dsanders, sdardis, llvm-commits

Differential Revision: http://reviews.llvm.org/D19715

llvm-svn: 268058
2016-04-29 16:16:49 +00:00
Daniel Sanders fba875f902 [mips][ias] Split expandMemInst between MipsAsmParser and MipsTargetStreamer. Almost NFC.
Summary:
The portion in MipsAsmParser is responsible for figuring out which expansion to
use, while the portion in MipsTargetStreamer is responsible for emitting it.

This allows us to remove the call to isIntegratedAssemblerRequired() which is
currently ensuring the effect of .cprestore only occurs when writing objects.

The small functional change is that the memory offsets are now correctly
printed as signed values.

Reviewers: sdardis

Subscribers: dsanders, sdardis, llvm-commits

Differential Revision: http://reviews.llvm.org/D19714

llvm-svn: 268042
2016-04-29 13:43:45 +00:00
Daniel Sanders a736b37a25 [mips][ias] Moved most instruction emission helpers to MipsTargetStreamer. NFC.
Summary:
* Moved all the emit*() helpers to MipsTargetStreamer.
* Moved createNop() to MipsTargetStreamer as emitNop() and emitEmptyDelaySlot().
  This instruction has been split to distinguish between the 'nop' instruction
  and the nop used in delay slots which is sometimes a different nop to the
  'nop' instruction (e.g. for short delay slots on microMIPS).
* Moved createAddu() to MipsTargetStreamer as emitAddu().
* Moved createAppropriateDSLL() to MipsTargetStreamer as emitDSLL().

Reviewers: sdardis

Subscribers: dsanders, sdardis, llvm-commits

Differential Revision: http://reviews.llvm.org/D19712

llvm-svn: 268041
2016-04-29 13:33:12 +00:00
Daniel Sanders c6924fa5d6 [mips][ias] Stream macro expansions to output instead of buffering them. NFC.
Summary:
This will allows us to eliminate some magic numbers from the offset operand of
branch instructions in favour of symbols and makes it possible to avoid
double-filling delay slots when clang is given -save-temps.

parseDirectiveCpRestore() is calling isIntegratedAssemblerRequired() for the
moment since correctly pushing the generation of these instructions into the
ELF target streamer is tricky enough to warrant a separate patch.

Reviewers: sdardis, vkalintiris

Subscribers: dsanders, llvm-commits, sdardis

Differential Revision: http://reviews.llvm.org/D19164

llvm-svn: 266602
2016-04-18 12:06:15 +00:00
Daniel Sanders f173dda0e2 [mips][ias] Implement .cpreturn directive.
Summary:
Based on a patch by David Chisnall. I've modified the original patch as follows:
* Moved the expansion to the TargetStreamers so that the directive isn't
  expanded when emitting assembly.
* Fixed an operand order bug.
* Changed the move instructions from DADDu to OR to match recent changes to GAS.

Reviewers: vkalintiris

Subscribers: llvm-commits, emaste, seanbruno, theraven

Differential Revision: http://reviews.llvm.org/D13017

llvm-svn: 248258
2015-09-22 10:50:09 +00:00
Daniel Sanders e2982adc0b [mips] Add assembler support for the .cprestore directive.
Summary:
This assembler directive is used in O32 PIC to restore the current function's $gp after executing JAL's. The $gp is first stored on the stack at a user-specified offset.
It has the following format: ".cprestore 8" (where 8 is the offset).

This fixes llvm.org/PR20967.

Patch by Toma Tabacu.

Reviewers: seanbruno, tomatabacu

Subscribers: brooks, seanbruno, emaste, llvm-commits

Differential Revision: http://reviews.llvm.org/D6267

llvm-svn: 247897
2015-09-17 16:08:39 +00:00
Simon Atanasyan 4d45c76895 [mips] Save a copy of MipsABIInfo in the MipsTargetStreamer to escape a dangling pointer
The MipsTargetELFStreamer can receive ABI info from many sources. For example,
from the MipsAsmParser instance. Lifetime of the MipsAsmParser can be shorter
than MipsTargetELFStreamer's lifetime. In that case we get a dangling pointer
to MipsABIInfo.

Differential Revision: http://reviews.llvm.org/D12805

llvm-svn: 247546
2015-09-14 11:18:03 +00:00
Toma Tabacu 0f09313051 [mips] [IAS] Add support for the .module softfloat/hardfloat directives.
These directives are used to set the default value of the SoftFloat feature.
They have the same effect as setting -m{soft, hard}-float from the command line.

Differential Revision: http://reviews.llvm.org/D9073

llvm-svn: 241066
2015-06-30 13:46:03 +00:00
Toma Tabacu 32c72aa099 [mips] [IAS] Add support for the .set oddspreg/nooddspreg directives.
Differential Revision: http://reviews.llvm.org/D10657

llvm-svn: 241052
2015-06-30 09:36:50 +00:00
Toma Tabacu a64e540511 [mips] [IAS] Refactor the emitDirectiveModuleFP() functions. NFC.
Summary:
Simplify emitDirectiveModuleFP() by having it just print the current information
from MipsABIFlagsSection and doing an updateABIInfo() before such calls.

This prevents us from forgetting to update the STI.FeatureBits,
because updateABIInfo() uses those to update the MipsABIFlagsSection object,
and also makes sure we use the update mechanism from MipsABIFlagsSection.

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits, mpf

Differential Revision: http://reviews.llvm.org/D10642

llvm-svn: 240637
2015-06-25 12:44:38 +00:00
Toma Tabacu 3c49958945 [mips] [IAS] Refactor the emitDirectiveModuleOddSPReg() functions. NFC.
Summary:
We can simplify emitDirectiveModuleOddSPReg() by having it print the current OddSPReg information
from MipsABIFlagsSection and doing an updateABIInfo() before such calls.

This prevents us from forgetting to update the STI.FeatureBits, because updateABIInfo() uses those to update the MipsABIFlagsSection object,
and also makes sure we use the update mechanism from MipsABIFlagsSection.

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits, mpf

Differential Revision: http://reviews.llvm.org/D10641

llvm-svn: 240630
2015-06-25 10:56:57 +00:00
Toma Tabacu bfcbfd56af [mips] [IAS] Move some function definitions to MipsTargetStreamer.cpp. NFC.
Summary: For the sake of consistency and to make some upcoming changes a little less noisy.

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D10639

llvm-svn: 240398
2015-06-23 12:34:19 +00:00
Alexander Kornienko f00654e31b Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)
Apparently, the style needs to be agreed upon first.

llvm-svn: 240390
2015-06-23 09:49:53 +00:00
Alexander Kornienko 70bc5f1398 Fixed/added namespace ending comments using clang-tidy. NFC
The patch is generated using this command:

tools/clang/tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
  -checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
  llvm/lib/


Thanks to Eugene Kosov for the original patch!

llvm-svn: 240137
2015-06-19 15:57:42 +00:00
Toma Tabacu 2969650ecd [mips] [IAS] Add support for the .set softfloat/hardfloat directives.
Summary: These directives are used to set the current value of the SoftFloat feature.

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits, mpf

Differential Revision: http://reviews.llvm.org/D9074

llvm-svn: 238813
2015-06-02 09:48:04 +00:00
Toma Tabacu 9ca5096f59 [mips] [IAS] Add support for the .insn directive.
Summary:
This assembler directive marks the current label as an instruction label in microMIPS and MIPS16.

This initial implementation works only for microMIPS.

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8006

llvm-svn: 235084
2015-04-16 09:53:47 +00:00
Toma Tabacu e95a49118c [mips] [IAS] Refactor MipsTargetStreamer::emitMipsAbiFlags(). NFC.
Summary: Make emitMipsAbiFlags a direct member of MipsTargetELFStreamer, as that's the only place where it's used, and remove the empty implementations from MipsTargetStreamer and MipsTargetAsmStreamer.

Reviewers: dsanders, rafael

Reviewed By: rafael

Subscribers: rafael, llvm-commits

Differential Revision: http://reviews.llvm.org/D8199

llvm-svn: 232161
2015-03-13 11:40:01 +00:00
Toma Tabacu 4e0cf8e211 [mips] [IAS] Add missing constraints and improve testing for the .module directive.
Summary:
None of the .set directives can be used before the .module directives. The .set mips0/pop/push were not triggering this constraint.
Also added testing for all the other implemented directives which are supposed to trigger this constraint.

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7140

llvm-svn: 231465
2015-03-06 12:15:12 +00:00
Daniel Sanders 1779314e3c [mips] Add backend support for Mips32r[35] and Mips64r[35].
Summary:
These ISA's didn't add any instructions so they are almost identical to
Mips32r2 and Mips64r2. Even the ELF e_flags are the same, However the ISA
revision in .MIPS.abiflags is 3 or 5 respectively instead of 2.

Reviewers: vmedic

Reviewed By: vmedic

Subscribers: tomatabacu, llvm-commits, atanasyan

Differential Revision: http://reviews.llvm.org/D7381

llvm-svn: 229695
2015-02-18 16:24:50 +00:00
Toma Tabacu 16a74499af [mips] Improve support for the .set at/noat assembler directives.
Summary:
Made the following changes:
  Added calls to emitDirectiveSetNoAt() and emitDirectiveSetAt().
  Added special emit function for .set at=$reg, emitDirectiveSetAtWithArg(unsigned RegNo).
  Improved parsing error checks for .set at.
  Refactored parser code for .set at.
  Improved testing of both directives.
  Improved code readability and comments.

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D7176

llvm-svn: 229097
2015-02-13 10:30:57 +00:00
Eric Christopher a576281694 Move the Mips target to storing the ABI in the TargetMachine rather
than on MipsSubtargetInfo.

This required a bit of massaging in the MC level to handle this since
MC is a) largely a collection of disparate classes with no hierarchy,
and b) there's no overarching equivalent to the TargetMachine, instead
only the subtarget via MCSubtargetInfo (which is the base class of
TargetSubtargetInfo).

We're now storing the ABI in both the TargetMachine level and in the
MC level because the AsmParser and the TargetStreamer both need to
know what ABI we have to parse assembly and emit objects. The target
streamer has a pointer to the one in the asm parser and is updated
when the asm parser is created. This is fragile as the FIXME comment
notes, but shouldn't be a problem in practice since we always
create an asm parser before attempting to emit object code via the
assembler. The TargetMachine now contains the ABI so that the DataLayout
can be constructed dependent upon ABI.

All testcases have been updated to use the -target-abi command line
flag so that we can set the ABI without using a subtarget feature.

Should be no change visible externally here.

llvm-svn: 227102
2015-01-26 17:33:46 +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
Toma Tabacu c4c202a9a7 [mips] Rename emit and parse functions for the .cpload assembler directive. NFC.
Summary: It's better if we have a consistent name for .cpload-related functions.

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D5437

llvm-svn: 218768
2014-10-01 14:53:19 +00:00
Toma Tabacu 351b2feeb3 [mips] Add assembler support for the .set nodsp directive.
Summary: This directive is used to tell the assembler to reject DSP-specific instructions.

Reviewers: dsanders

Reviewed By: dsanders

Differential Revision: http://reviews.llvm.org/D5142

llvm-svn: 217946
2014-09-17 09:01:54 +00:00
Toma Tabacu 2664779b27 [mips] Add assembler support for .set mips0 directive.
Summary:
This directive is used to reset the assembler options to their initial values.
Assembly programmers use it in conjunction with the ".set mipsX" directives.

This patch depends on the .set push/pop directive (http://reviews.llvm.org/D4821).

Contains work done by Matheus Almeida.

Reviewers: dsanders

Reviewed By: dsanders

Differential Revision: http://reviews.llvm.org/D4957

llvm-svn: 217438
2014-09-09 12:52:14 +00:00
Toma Tabacu 9db22db963 [mips] Add assembler support for .set push/pop directive.
Summary:
These directives are used to save the current assembler options (in the case of ".set push") and restore the previously saved options (in the case of ".set pop").

Contains work done by Matheus Almeida.

Reviewers: dsanders

Reviewed By: dsanders

Differential Revision: http://reviews.llvm.org/D4821

llvm-svn: 217432
2014-09-09 10:15:38 +00:00
Benjamin Kramer 8c90fd71f7 Add override to overriden virtual methods, remove virtual keywords.
No functionality change. Changes made by clang-tidy + some manual cleanup.

llvm-svn: 217028
2014-09-03 11:41:21 +00:00
Toma Tabacu 85618b3194 [mips] Add assembler support for .set arch=x directive.
Summary:
This directive is similar to ".set mipsX".
It is used to change the CPU target of the assembler, enabling it to accept instructions for a specific CPU.

This patch only implements the r4000 CPU (which is treated internally as generic mips3) and the generic ISAs.

Contains work done by Matheus Almeida.

Reviewers: dsanders

Reviewed By: dsanders

Differential Revision: http://reviews.llvm.org/D4884

llvm-svn: 215978
2014-08-19 14:22:52 +00:00
Daniel Sanders cdb45fa391 [mips] Rename [gs]etCanHaveModuleDir to more natural names
Summary:
getCanHaveModuleDir() is renamed to isModuleDirectiveAllowed(), and
setCanHaveModuleDir() is renamed to forbidModuleDirective() since it is only
ever given a false argument.

Reviewers: vmedic

Reviewed By: vmedic

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D4885

llvm-svn: 215628
2014-08-14 09:18:14 +00:00
Benjamin Kramer a7c40ef022 Canonicalize header guards into a common format.
Add header guards to files that were missing guards. Remove #endif comments
as they don't seem common in LLVM (we can easily add them back if we decide
they're useful)

Changes made by clang-tidy with minor tweaks.

llvm-svn: 215558
2014-08-13 16:26:38 +00:00
Toma Tabacu 88f05ce30e [mips] Refactor calls to setCanHaveModuleDir.
Summary:
Moved some calls to setCanHaveModuleDir to the MipsTargetStreamer base class and removed the resulting empty functions from the MipsTargetELFStreamer class.

Also fixed a missing call to setCanHaveModuleDir in MipsTargetELFStreamer::emitDirectiveSetMicroMips.

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: tomatabacu

Differential Revision: http://reviews.llvm.org/D4781

llvm-svn: 215542
2014-08-13 12:48:12 +00:00
Daniel Sanders d97a634f12 Re-commit: [mips] Implement .ent, .end, .frame, .mask and .fmask.
Patch by Matheus Almeida and Toma Tabacu

The lld test failure on the previous attempt to commit was caused by the
addition of the .pdr section causing the offsets it was checking to change.
This has been fixed by removing the .ent/.end directives from that test since
they weren't really needed.

llvm-svn: 215535
2014-08-13 10:07:34 +00:00
Daniel Sanders b9bc75b625 Revert r215359 - [mips] Implement .ent, .end, .frame, .mask and .fmask assembler directives
It seems to cause an lld test (elf/Mips/hilo16-3.test) to fail. Reverted while we investigate.

llvm-svn: 215361
2014-08-11 16:10:19 +00:00
Daniel Sanders 21cf026893 [mips] Implement .ent, .end, .frame, .mask and .fmask assembler directives
Patch by Matheus Almeida and Toma Tabacu

Differential Revision: http://reviews.llvm.org/D4179

llvm-svn: 215359
2014-08-11 15:28:56 +00:00
Daniel Sanders 449344315f [mips] Add assembler support for .set msa/nomsa directive.
Summary:
These directives are used to toggle whether the assembler accepts MSA-specific instructions or not.

Patch by Matheus Almeida and Toma Tabacu.

Reviewers: dsanders

Reviewed By: dsanders

Differential Revision: http://reviews.llvm.org/D4783

llvm-svn: 215099
2014-08-07 12:03:36 +00:00
Daniel Sanders f0df221d76 [mips] Add assembler support for '.set mipsX'.
Summary:
This patch also fixes an issue with the way the Mips assembler enables/disables architecture
features. Before this patch, the assembler never disabled feature bits. For example,
.set mips64
.set mips32r2

would result in the 'OR' of mips64 with mips32r2 feature bits which isn't right.
Unfortunately this isn't trivial to fix because there's not an easy way to clear
feature bits as the algorithm in MCSubtargetInfo (ToggleFeature) only clears the bits
that imply the feature being cleared and not the implied bits by the feature (there's a
better explanation to the code I added).

Patch by Matheus Almeida and updated by Toma Tabacu

Reviewers: vmedic, matheusalmeida, dsanders

Reviewed By: dsanders

Subscribers: tomatabacu, llvm-commits

Differential Revision: http://reviews.llvm.org/D4123

llvm-svn: 214709
2014-08-04 12:20:00 +00:00
Daniel Sanders 7e527423f5 [mips] Add support for -modd-spreg/-mno-odd-spreg
Summary:
When -mno-odd-spreg is in effect, 32-bit floating point values are not
permitted in odd FPU registers. The option also prohibits 32-bit and 64-bit
floating point comparison results from being written to odd registers.

This option has three purposes:
* It allows support for certain MIPS implementations such as loongson-3a that
  do not allow the use of odd registers for single precision arithmetic.
* When using -mfpxx, -mno-odd-spreg is the default and this allows us to
  statically check that code is compliant with the O32 FPXX ABI since mtc1/mfc1
  instructions to/from odd registers are guaranteed not to appear for any
  reason. Once this has been established, the user can then re-enable
  -modd-spreg to regain the use of all 32 single-precision registers.
* When using -mfp64 and -mno-odd-spreg together, an O32 extension named
  O32 FP64A is used as the ABI. This is intended to provide almost all
  functionality of an FR=1 processor but can also be executed on a FR=0 core
  with the assistance of a hardware compatibility mode which emulates FR=0
  behaviour on an FR=1 processor.

* Added '.module oddspreg' and '.module nooddspreg' each of which update
  the .MIPS.abiflags section appropriately
* Moved setFpABI() call inside emitDirectiveModuleFP() so that the caller
  doesn't have to remember to do it.
* MipsABIFlags now calculates the flags1 and flags2 member on demand rather
  than trying to maintain them in the same format they will be emitted in.

There is one portion of the -mfp64 and -mno-odd-spreg combination that is not
implemented yet. Moves to/from odd-numbered double-precision registers must not
use mtc1. I will fix this in a follow-up.

Differential Revision: http://reviews.llvm.org/D4383

llvm-svn: 212717
2014-07-10 13:38:23 +00:00
NAKAMURA Takumi 843c4cb401 MipsTargetStreamer.h: Avoid "using" to appease msc17.
llvm-svn: 212577
2014-07-08 23:48:22 +00:00
Daniel Sanders 324ad956e0 [mips] Fixed struct/class mismatch introduced in r212522.
Clang emits a warning about this.

llvm-svn: 212528
2014-07-08 13:13:42 +00:00
Daniel Sanders c7dbc630e5 [mips] Improve encapsulation of the .MIPS.abiflags implementation and limit scope of related enums
Summary:
Follow on to r212519 to improve the encapsulation and limit the scope of the enums.

Also merged two very similar parser functions, fixed a bug where ASE's
were not being reported, and marked CPR1's as being 128-bit when MSA is
enabled.

Differential Revision: http://reviews.llvm.org/D4384

llvm-svn: 212522
2014-07-08 10:11:38 +00:00
Vladimir Medic fb8a2a95cd Mips.abiflags is a new implicitly generated section that will be present on all new modules. The section contains a versioned data structure which represents essentially information to allow a program loader to determine the requirements of the application. This patch implements mips.abiflags section and provides test cases for it.
llvm-svn: 212519
2014-07-08 08:59:22 +00:00
Rafael Espindola 60890b8910 [Mips] Add a target streamer when creating a null streamer.
Should fix DebugInfo/global.ll on the mips bot.

llvm-svn: 211527
2014-06-23 19:43:40 +00:00
Matheus Almeida d92a3fa212 [mips] Move expansion of .cpsetup to target streamer.
Summary:
There are two functional changes:
1) The directive is not expanded for the ASM->ASM code path.
2) If PIC is not set, there's no expansion for the ASM->OBJ code path (same behaviour as GAS).

Reviewers: dsanders

Reviewed By: dsanders

Differential Revision: http://reviews.llvm.org/D3482

llvm-svn: 207741
2014-05-01 10:24:46 +00:00
Matheus Almeida 525bc4f708 [mips] Add support for .cpload.
Summary:
This directive is used for setting up $gp in the beginning of a function.
It expands to three instructions if PIC is enabled:
lui   $gp, %hi(_gp_disp)
addui $gp, $gp, %lo(_gp_disp)
addu  $gp, $gp, $reg

_gp_disp is a special symbol that the linker sets to the distance between
the lui instruction and the context pointer (_gp).

Reviewers: dsanders

Reviewed By: dsanders

Differential Revision: http://reviews.llvm.org/D3480

llvm-svn: 207637
2014-04-30 11:28:42 +00:00