Commit Graph

1868 Commits

Author SHA1 Message Date
Rafael Espindola
7376033762 Be sure to set the DataLayout before checking the cache.
This makes sure the same mangling is used.

Should fix the OS X bots.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240411 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-23 14:42:34 +00:00
Rafael Espindola
9758b4ae95 Simplify the Mangler interface now that DataLayout is mandatory.
We only need to pass in a DataLayout when mangling a raw string, not when
constructing the mangler.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240405 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-23 13:59:29 +00:00
Petar Jovanovic
7c5bf4d38a [mips64] Emit correct addend for some PC-relative relocations
So far, LLVM has not emitted correct addend for N64 and N32 ABI. This patch
fixes that. It also removes fixup from MCJIT for R_MIPS_PC16 relocation.

Patch by Vladimir Radosavljevic.

Differential Revision: http://reviews.llvm.org/D10565


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240404 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-23 13:54:42 +00:00
Alexander Kornienko
cd52a7a381 Revert r240137 (Fixed/added namespace ending comments using clang-tidy. NFC)
Apparently, the style needs to be agreed upon first.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240390 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-23 09:49:53 +00:00
Joseph Tremoulet
864619a387 Fix line endings (NFC)
I inadvertently checked these in with Windows-style line
endings in r240288.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240340 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-22 21:37:34 +00:00
Joseph Tremoulet
c29284e6c3 [ORC] Add NullResolver
Summary:
This is an implementation of RuntimeDyld::SymbolResolver that simply
rejects all resolution requests; useful for clients that do not have any
cross-object symbol references.

Reviewers: lhames

Reviewed By: lhames

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D10455

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240288 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-22 15:27:58 +00:00
Keno Fischer
bea6fb975e [MCJIT] Add a FindGlobalVariableNamed utility
Summary: This adds FindGlobalVariableNamed to ExecutionEngine
(plus implementation in MCJIT), which is an analog of
FindFunctionNamed for GlobalVariables.

Reviewers: lhames

Reviewed By: lhames

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D10421

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240202 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-20 00:55:58 +00:00
Rafael Espindola
7edd010739 Improve error handling of getRelocationAddend.
This patch changes getRelocationAddend to use ErrorOr and considers it an error
to try to get the addend of a REL section.

If, for example, a x86_64 file has a REL section, that file is corrupted and
we should reject it.

Using ErrorOr is not ideal since we check the section type once per relocation
instead of once per section.

Checking once per section would involve getRelocationAddend just asserting and
callers checking the section before iterating over the relocations.

In any case, this is an improvement and includes a test.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240176 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-19 20:58:43 +00:00
Douglas Katzman
ae7a59fa3e Avoid warning about inability to cast from ptr-to-obj to ptr-to-fun.
Use POSIX.1-2003 Technical Corrigendum 1 suggested workaround.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240140 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-19 17:21:02 +00:00
Alexander Kornienko
cf0db29df2 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!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@240137 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-19 15:57:42 +00:00
Duncan P. N. Exon Smith
5449852030 modules: Add explicit dependency on intrinsics_gen
`LLVM_ENABLE_MODULES` builds sometimes fail because `Intrinsics.td`
needs to regenerate `Instrinsics.h` before anyone can include anything
from the LLVM_IR module.  Represent the dependency explicitly to prevent
that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239796 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-16 00:44:12 +00:00
Benjamin Kramer
4bb355e885 [ExecutionEngine] ArrayRefize argument passing.
No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239687 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-13 19:50:29 +00:00
Lang Hames
fe8e55cbc0 [Orc] Fix a bug in the CompileOnDemand layer where stub decls were not cloned
into partitions. Also, add an option to clone stub definitions (not just decls)
into partitions: these definitions could be inlined in some places to avoid the
overhead of calling via the stub.

Found by inspection - no test case yet, although I plan to add a unit test for
this once the CompileOnDemand layer refactoring settles down.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239640 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-12 21:31:15 +00:00
Alexei Starovoitov
e11157c668 fix crash
fix segfault by checking for UnknownArch, since
getArchTypePrefix() will return nullptr for UnknownArch.

This fixes regression caused by r238424.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239456 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-10 03:06:06 +00:00
Rui Ueyama
eae4673c2f Remove object_error::success and use std::error_code() instead
make_error_code(object_error) is slow because object::object_category()
uses a ManagedStatic variable. But the real problem is that the function is
called too frequently. This patch uses std::error_code() instead of
object_error::success. In most cases, we return "success", so this patch
reduces number of function calls to that function.

http://reviews.llvm.org/D10333



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239409 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-09 15:20:42 +00:00
Petar Jovanovic
f8aad6c1ef [Mips64][mcjit] Add R_MIPS_PC32 relocation
This patch adds R_MIPS_PC32 relocation for Mips64.

Patch by Vladimir Radosavljevic.

Differential Revision: http://reviews.llvm.org/D10235


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239301 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-08 14:10:23 +00:00
Daniel Sanders
682b194cd6 Re-commit r238838, r238844 with fix for host/target endian mismatch and windows buildbot.
The windows buildbot originally failed because the check expressions are
evaluated as 64-bit values, even for 32-bit symbols. Fixed this by comparing
bottom 32-bits of the expressions.

The host/target endian mismatch issue is that it's invalid to read/write target
values using a host pointer without taking care of endian differences between
the target and host. Most (if not all) instances of
reinterpret_cast<uint32_t*>() in the RuntimeDyld are examples of this bug.
This has been fixed for Mips using the endian aware read/write functions.

The original commits were:
r238838:
[mips] Add RuntimeDyld tests for currently supported O32 relocations.

Reviewers: petarj, vkalintiris

Reviewed By: vkalintiris

Subscribers: vkalintiris, llvm-commits

Differential Revision: http://reviews.llvm.org/D10126

r238844:
[mips][mcjit] Add support for R_MIPS_PC32.

Summary:
This allows us to resolve relocations for DW_EH_PE_pcrel TType encodings
in the exception handling LSDA.

Also fixed a nearby typo.

Reviewers: petarj, vkalintiris

Reviewed By: vkalintiris

Subscribers: vkalintiris, llvm-commits

Differential Revision: http://reviews.llvm.org/D10127



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238915 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-03 10:27:28 +00:00
Rafael Espindola
60e0898710 This reverts commit r238838, r238844 and r238888.
Trying to bring back a windows bot:

http://lab.llvm.org:8011/builders/clang-x86-win2008-selfhost/builds/1224/steps/ninja%20check%202/logs/FAIL%3A%20LLVM%3A%3AELF_O32_PIC_relocations.s

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238903 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-03 05:39:59 +00:00
Daniel Sanders
6c55f8dda7 [mips][mcjit] Add support for R_MIPS_PC32.
Summary:
This allows us to resolve relocations for DW_EH_PE_pcrel TType encodings
in the exception handling LSDA.

Also fixed a nearby typo.

Reviewers: petarj, vkalintiris

Reviewed By: vkalintiris

Subscribers: vkalintiris, llvm-commits

Differential Revision: http://reviews.llvm.org/D10127

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238844 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-02 15:28:29 +00:00
Rafael Espindola
9751e35f20 Simplify now that we always use an alignment of 2 for ELF files.
This saves 123144 bytes out of llvm-nm on powerpc64le.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238824 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-02 12:05:27 +00:00
Davide Italiano
69aef63931 [RuntimeDydlELF] Use range-based loop.
Differential Revision:	http://reviews.llvm.org/D10165
Reviewed by:	rafael


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238804 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-02 01:52:28 +00:00
Sanjay Patel
2c403d6891 add missing dependency for ExecutionEngine lib
This appears to be masked most of the time, but the problem
was exposed on some bots by r238051.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238788 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-01 21:56:56 +00:00
Rafael Espindola
dd2e39c453 Try to fix the build of IntelJITEventListener.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238709 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-01 02:18:14 +00:00
Rafael Espindola
481f35f113 Simplify another function that doesn't fail.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238703 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-01 00:27:26 +00:00
Rafael Espindola
64afb8375d Simplify interface of function that doesn't fail.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238700 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-31 23:52:50 +00:00
Benjamin Kramer
9589ff8949 Replace push_back(Constructor(foo)) with emplace_back(foo) for non-trivial types
If the type isn't trivially moveable emplace can skip a potentially
expensive move. It also saves a couple of characters.


Call sites were found with the ASTMatcher + some semi-automated cleanup.

memberCallExpr(
    argumentCountIs(1), callee(methodDecl(hasName("push_back"))),
    on(hasType(recordDecl(has(namedDecl(hasName("emplace_back")))))),
    hasArgument(0, bindTemporaryExpr(
                       hasType(recordDecl(hasNonTrivialDestructor())),
                       has(constructExpr()))),
    unless(isInTemplateInstantiation()))

No functional change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238602 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-29 19:43:39 +00:00
Petar Jovanovic
a703f676f7 [Mips64] Add support for MCJIT for MIPS64r2 and MIPS64r6
Add support for resolving MIPS64r2 and MIPS64r6 relocations in MCJIT.

Patch by Vladimir Radosavljevic.

Differential Revision: http://reviews.llvm.org/D9667


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238424 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-28 13:48:41 +00:00
Lang Hames
8cc212a07e [RuntimeDyld] Fix MachO i386 SECTDIFF relocation to support non-zero addends.
Previously, relocations of the form 'A - B + C' would fail on i386 when C was
non-zero.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238356 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-27 20:50:01 +00:00
Akira Hatanaka
6f49135066 Remove NoFramePointerElim and NoFramePointerElimOverride from TargetOptions and
remove ExecutionEngine's dependence on CodeGen. NFC.

This is a follow-up to r238080.

Differential Revision: http://reviews.llvm.org/D9830


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238244 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-26 20:17:20 +00:00
NAKAMURA Takumi
c1c3e6c7ec Update ExecutionEngine/LLVMBuild.txt, to add LLVMCodeGen.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238096 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-23 10:44:30 +00:00
Akira Hatanaka
01461204b3 Stop resetting NoFramePointerElim in TargetMachine::resetTargetOptions.
This is part of the work to remove TargetMachine::resetTargetOptions.

In this patch, instead of updating global variable NoFramePointerElim in
resetTargetOptions, its use in DisableFramePointerElim is replaced with a call
to TargetFrameLowering::noFramePointerElim. This function determines on a
per-function basis if frame pointer elimination should be disabled.

There is no change in functionality except that cl:opt option "disable-fp-elim"
can now override function attribute "no-frame-pointer-elim". 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238080 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-23 01:14:08 +00:00
NAKAMURA Takumi
25103832b2 Reapply part of r237975, "Fix Clang -Wmissing-override warning", except for DIContext.h, to apease g++-4.7.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238012 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-22 10:11:07 +00:00
Tobias Grosser
b7888bd5ea Revert "Fix Clang -Wmissing-override warning"
This reverts commit r237975. This seems also to break with gcc 4.7

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238004 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-22 06:01:04 +00:00
David Blaikie
a89d43a2ce Fix Clang -Wmissing-override warning
& remove the duplication by introducing a CRTP base to implement the
clone behavior.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237975 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-22 00:00:00 +00:00
Keno Fischer
b6976af3cd Make it easier to use DwarfContext with MCJIT
Summary:
This supersedes http://reviews.llvm.org/D4010, hopefully properly
dealing with the JIT case and also adds an actual test case.
DwarfContext was basically already usable for the JIT (and back when
we were overwriting ELF files it actually worked out of the box by
accident), but in order to resolve relocations correctly it needs
to know the load address of the section.
Rather than trying to get this out of the ObjectFile or requiring
the user to create a new ObjectFile just to get some debug info,
this adds the capability to pass in that info directly.
As part of this I separated out part of the LoadedObjectInfo struct
from RuntimeDyld, since it is now required at a higher layer.

Reviewers: lhames, echristo

Reviewed By: echristo

Subscribers: vtjnash, friss, rafael, llvm-commits

Differential Revision: http://reviews.llvm.org/D6961

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237961 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-21 21:24:32 +00:00
David Majnemer
e892415f25 [RuntimeDyld] Use isInt to assert that a relocation didn't overflow
isInt is a little easier to read, let's use that more consistently.
Incidentally, this also silences a warning for shifting a negative
number.

This fixes PR23532.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237476 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-15 20:32:25 +00:00
David Blaikie
bbd301d97a Readdress r236990, use of static members on a non-static variable.
The TargetRegistry is just a namespace-like class, instantiated in one
place to use a range-based for loop. Instead, expose access to the
registry via a range-based 'targets()' function instead. This makes most
uses a bit awkward/more verbose - but eventually we should just add a
range-based find_if function which will streamline these functions. I'm
happy to mkae them a bit awkward in the interim as encouragement to
improve the algorithms in time.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237059 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-11 22:20:48 +00:00
Lang Hames
1aeb111842 [Orc] Reapply r236465 with fixes for the MSVC bots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236506 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-05 17:37:18 +00:00
Lang Hames
b63d8107f0 [Orc] Revert r236465 - It broke the Windows bots.
Looks like the usual missing explicit move-constructor issue with MSVC. I should
have a fix shortly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236472 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-04 23:30:01 +00:00
Lang Hames
ee160106a1 [Orc] Refactor the compile-on-demand layer to make module partitioning lazy,
and avoid cloning unused decls into every partition.

Module partitioning showed up as a source of significant overhead when I
profiled some trivial test cases. Avoiding the overhead of partitionging
for uncalled functions helps to mitigate this.

This change also means that it is no longer necessary to have a
LazyEmittingLayer underneath the CompileOnDemand layer, since the
CompileOnDemandLayer will not extract or emit function bodies until they are
called.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236465 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-04 22:03:10 +00:00
Keno Fischer
277d81e680 Reapply [RuntimeDyldELF] Fold Placeholder into Addend
This reapplies r235060 and 235070, which were reverted because of test failures
in LLDB. The failure was caused because at  moment RuntimeDyld is processing
relocations for all sections, irrespective of whether we actually load them
into memory or not, but RuntimeDyld was not actually remembering where in memory
the unrelocated section is. This commit includes a fix for that issue by
remembering that pointer, though the longer term fix should be to stop processing
unneeded sections.

Original Summary:

This allows us to get rid of the original unrelocated object file after
we're done processing relocations (but before applying them).
MachO and COFF already do not require this (currently we have temporary hacks
to prevent ownership from being released, but those are brittle and should be
removed soon).

The placeholder mechanism allowed the relocation resolver to look at original
object file to obtain more information that are required to apply the
relocations. This is usually necessary in two cases:

- For relocations targetting sub-word memory locations, there may be pieces
  of the instruction at the target address which we should not override.
- Some relocations on some platforms allow an extra addend to be encoded in
  their immediate fields.

The problem is that in the second case the information cannot be recovered
after the relocations have been applied once because they will have been
overridden. In the first case we also need to be careful to not use any bits
that aren't fixed and may have been overriden by applying a first relocation.

In the past both have been fixed by just looking at original object file. This
patch attempts to recover the information from the first by looking at the
relocated object file, while the extra addend in the second case is read
upon relocation processing and addend to the regular addend.

I have tested this on X86. Other platforms represent my best understanding
of how those relocations should work, but I may have missed something because
I do not have access to those platforms.
We will keep the ugly workarounds in place for a couple of days, so this commit
can be reverted if it breaks the bots.

Differential Revision: http://reviews.llvm.org/D9028

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236341 91177308-0d34-0410-b5e6-96231b3b80d8
2015-05-01 20:21:45 +00:00
David Blaikie
39e7388a19 [opaque pointer type] Pass GlobalAlias the actual pointer type rather than decomposing it into pointee type + address space
Many of the callers already have the pointer type anyway, and for the
couple of callers that don't it's pretty easy to call PointerType::get
on the pointee type and address space.

This avoids LLParser from using PointerType::getElementType when parsing
GlobalAliases from IR.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236160 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-29 21:22:39 +00:00
Zachary Turner
45e7e93c6f Move DIContext.h to common DebugInfo location.
This will enable us to create a PDBContext so as to expose some
amount of debug info functionality through a common interace.

Differential Revision: http://reviews.llvm.org/D9205
Reviewed by: Alexey Samsonov

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235612 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-23 17:37:47 +00:00
Lang Hames
14660f8f21 [RuntimeDyld][COFF] Add external symbol resolution support to RuntimeDyldCOFF.
Patch by Andy Ayers. Thanks Andy!



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235554 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-22 21:38:37 +00:00
Lang Hames
302f000bf4 [Orc] Make the makeStub function propagate argument attributes onto the call to
the function body.

This is necessary for correctness when lazily compiling.

Also, flesh out the Orc unit test infrastructure slightly, and add a unit test
for this.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235347 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-20 20:41:45 +00:00
Lang Hames
4943838e28 [Orc] Use the 64-bit versions of FXSAVE/FXRSTOR for JIT reentry.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235325 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-20 18:25:44 +00:00
Pavel Labath
61cf1a8047 Revert "[RuntimeDyldELF] Fold Placeholder into Addend"
This reverts commit cbbeac14f0.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235082 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-16 08:58:15 +00:00
Pavel Labath
e0eb40474c Revert "[RuntimeDyldELF] Fix missing cases in Placeholder processing"
This reverts commit ec0a34f850.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235081 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-16 08:58:11 +00:00
Keno Fischer
ec0a34f850 [RuntimeDyldELF] Fix missing cases in Placeholder processing
Try to appease the build bots. We should write rtdyld test cases for these
to make them testible on other platforms.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235070 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-16 02:00:38 +00:00
Keno Fischer
cbbeac14f0 [RuntimeDyldELF] Fold Placeholder into Addend
Summary:

This allows us to get rid of the original unrelocated object file after
we're done processing relocations (but before applying them).
MachO and COFF already do not require this (currently we have temporary hacks
to prevent ownership from being released, but those are brittle and should be
removed soon).

The placeholder mechanism allowed the relocation resolver to look at original
object file to obtain more information that are required to apply the
relocations. This is usually necessary in two cases:

- For relocations targetting sub-word memory locations, there may be pieces
  of the instruction at the target address which we should not override.
- Some relocations on some platforms allow an extra addend to be encoded in
  their immediate fields.

The problem is that in the second case the information cannot be recovered
after the relocations have been applied once because they will have been
overridden. In the first case we also need to be careful to not use any bits
that aren't fixed and may have been overriden by applying a first relocation.

In the past both have been fixed by just looking at original object file. This
patch attempts to recover the information from the first by looking at the
relocated object file, while the extra addend in the second case is read
upon relocation processing and addend to the regular addend.

I have tested this on X86. Other platforms represent my best understanding
of how those relocations should work, but I may have missed something because
I do not have access to those platforms.
We will keep the ugly workarounds in place for a couple of days, so this commit
can be reverted if it breaks the bots.

Reviewers: petarj, t.p.northover, lhames

Reviewed By: lhames

Subscribers: aemerson, llvm-commits

Differential Revision: http://reviews.llvm.org/D9028

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235060 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-15 23:49:29 +00:00