For COFF and MachO, sections semantically have relocations that apply to them.
That is not the case on ELF.
In relocatable objects (.o), a section with relocations in ELF has offsets to
another section where the relocations should be applied.
In dynamic objects and executables, relocations don't have an offset, they have
a virtual address. The section sh_info may or may not point to another section,
but that is not actually used for resolving the relocations.
This patch exposes that in the ObjectFile API. It has the following advantages:
* Most (all?) clients can handle this more efficiently. They will normally walk
all relocations, so doing an effort to iterate in a particular order doesn't
save time.
* llvm-readobj now prints relocations in the same way the native readelf does.
* probably most important, relocations that don't point to any section are now
visible. This is the case of relocations in the rela.dyn section. See the
updated relocation-executable.test for example.
llvm-svn: 182908
Previously we would read-modify-write the target bits when processing
relocations for the MCJIT. This had the problem that when relocations
were processed multiple times for the same object file (as they can
be), the result is not idempotent and the values became corrupted.
The solution to this is to take any bits used in the destination from
the pristine object file as LLVM emitted it.
This should fix PR16013 and remote MCJIT on ARM ELF targets.
llvm-svn: 182800
libExecutionEngine. Move method implementations that aren't specific to
allocation out of SectionMemoryManager and into RTDyldMemoryManager.
This is in preparation for exposing RTDyldMemoryManager through the C
API.
This is a fixed version of r182407 and r182411. That first revision
broke builds because I forgot to move the conditional includes of
various POSIX headers from SectionMemoryManager into
RTDyldMemoryManager. Those includes are necessary because of how
getPointerToNamedFunction works around the glibc libc_nonshared.a thing.
The latter revision still broke things because I forgot to include
llvm/Config/config.h.
llvm-svn: 182418
libExecutionEngine. Move method implementations that aren't specific to
allocation out of SectionMemoryManager and into RTDyldMemoryManager.
This is in preparation for exposing RTDyldMemoryManager through the C
API.
This is a fixed version of r182407. That revision broke builds because I
forgot to move the conditional includes of various POSIX headers from
SectionMemoryManager into RTDyldMemoryManager. Those includes are
necessary because of how getPointerToNamedFunction works around the
glibc libc_nonshared.a thing.
llvm-svn: 182411
libExecutionEngine. Move method implementations that aren't specific to
allocation out of SectionMemoryManager and into RTDyldMemoryManager.
This is in preparation for exposing RTDyldMemoryManager through the C
API.
llvm-svn: 182407
AArch64 ELF uses .rela relocations so there's no need to actually make
use of the bits we're setting in the destination However, we should
make sure all bits are cleared properly since multiple runs of
resolveRelocations are possible and these could combine to produce
invalid results if stale versions remain in the code.
llvm-svn: 182214
This gets exception handling working on ELF and Macho (x86-64 at least).
Other than the EH frame registration, this patch also implements support
for GOT relocations which are used to locate the personality function on
MachO.
llvm-svn: 181167
This is about the simplest relocation, but surprisingly rare in actual
code.
It occurs in (for example) the MCJIT test test-ptr-reloc.ll.
llvm-svn: 181134
As with global accesses, external functions could exist anywhere in
memory. Therefore the stub must create a complete 64-bit address. This
patch implements the fragment as (roughly):
movz x16, #:abs_g3:somefunc
movk x16, #:abs_g2_nc:somefunc
movk x16, #:abs_g1_nc:somefunc
movk x16, #:abs_g0_nc:somefunc
br x16
In principle we could save 4 bytes by using a literal-load instead,
but it is unclear that would be more efficient and can only be tested
when real hardware is readily available.
This allows (for example) the MCJIT test 2003-05-07-ArgumentTest to
pass on AArch64.
llvm-svn: 181133
The large memory model (default and main viable for JIT) emits
addresses in need of relocation as
movz x0, #:abs_g3:somewhere
movk x0, #:abs_g2_nc:somewhere
movk x0, #:abs_g1_nc:somewhere
movk x0, #:abs_g0_nc:somewhere
To support this we must implement those four relocations in the
dynamic loader.
This allows (for example) the test-global.ll MCJIT test to pass on
AArch64.
llvm-svn: 181132
R_AARCH64_PCREL32 is present in even trivial .eh_frame sections and so
is required to compile any function without the "nounwind" attribute.
This change implements very basic infrastructure in the RuntimeDyldELF
file and allows (for example) the test-shift.ll MCJIT test to pass
on AArch64.
llvm-svn: 181131
Another step towards reinstating the SystemZ backend. I'll commit
the configure changes separately (TARGET_HAS_JIT etc.), then commit
a patch to enable the MCJIT tests on SystemZ.
llvm-svn: 181015
For regular object files this is only meaningful for common symbols. An object
file format with direct support for atoms should be able to provide alignment
information for all symbols.
This replaces getCommonSymbolAlignment and fixes
test-common-symbols-alignment.ll on darwin. This also includes a fix to
MachOObjectFile::getSymbolFlags. It was marking undefined symbols as common
(already tested by existing mcjit tests now that it is used).
llvm-svn: 180736
The implemented RuntimeDyldImpl interface is public. Everything else is private.
Since these classes are not inherited from (yet), there is no need to have
protected members.
llvm-svn: 180733
For MachO we need information that is not represented in ObjRelocationInfo.
Instead of copying the bits we think are needed from a relocation_iterator,
just pass the relocation_iterator down to the format specific functions.
No functionality change yet as we still drop the information once
processRelocationRef returns.
llvm-svn: 180711
For Mach-O there were 2 implementations for parsing object files. A
standalone llvm/Object/MachOObject.h and llvm/Object/MachO.h which
implements the generic interface in llvm/Object/ObjectFile.h.
This patch adds the missing features to MachO.h, moves macho-dump to
use MachO.h and removes ObjectFile.h.
In addition to making sure that check-all is clean, I checked that the
new version produces exactly the same output in all Mach-O files in a
llvm+clang build directory (including executables and shared
libraries).
To test the performance, I ran macho-dump over all the files in a
llvm+clang build directory again, but this time redirecting the output
to /dev/null. Both the old and new versions take about 4.6 seconds
(2.5 user) to finish.
llvm-svn: 180624
* We only ever specialize these templates with an instantiation of ELFType,
so we don't need a template template.
* Replace LLVM_ELF_COMMA with just passing the individual parameters to the
macro. This requires a second macro for when we only have ELFT, but that
is still a small win.
llvm-svn: 179726
I will remove the isBigEndianHost function once I update clang.
The ifdef logic is designed to
* not use configure/cmake to avoid breaking -arch i686 -arch ppc.
* default to little endian
* be as small as possible
It looks like sys/endian.h is the preferred header on most modern BSD systems,
but it is better to change this in a followup patch as machine/endian.h is
available on FreeBSD, OpenBSD, NetBSD and OS X.
llvm-svn: 179527
When the RuntimeDyldELF::processRelocationRef routine finds the target
symbol of a relocation in the local or global symbol table, it performs
a section-relative relocation:
Value.SectionID = lsi->second.first;
Value.Addend = lsi->second.second;
At this point, however, any Addend that might have been specified in
the original relocation record is lost. This is somewhat difficult to
trigger for relocations within the code section since they usually
do not contain non-zero Addends (when built with the default JIT code
model, in any case). However, the problem can be reliably triggered
by a relocation within the data section caused by code like:
int test[2] = { -1, 0 };
int *p = &test[1];
The initializer of "p" will need a relocation to "test + 4". On
platforms using RelA relocations this means an Addend of 4 is required.
Current code ignores this addend when processing the relocation,
resulting in incorrect execution.
Fixed by taking the Addend into account when processing relocations
to symbols found in the local or global symbol table.
Tested on x86_64-linux and powerpc64-linux.
llvm-svn: 178869
This simplifies the usage and implementation of ELFObjectFile by using ELFType
to replace:
<endianness target_endianness, std::size_t max_alignment, bool is64Bits>
This does complicate the base ELF types as they must now use template template
parameters to partially specialize for the 32 and 64bit cases. However these
are only defined once.
llvm-svn: 172515
This patch adjust the r171506 to make all DWARF enconding pc-relative
for PPC64. It also adds the R_PPC64_REL32 relocation handling in MCJIT
(since the eh_frame will not generate PIC-relative relocation) and also
adds the emission of stubs created by the TTypeEncoding.
llvm-svn: 171979
This patch fixes the PPC eh_frame definitions for the personality and
frame unwinding for PIC objects. It makes PIC build correctly creates
relative relocations in the '.rela.eh_frame' segments and thus avoiding
a text relocation that generates a DT_TEXTREL segments in link phase.
llvm-svn: 171506
missed in the first pass because the script didn't yet handle include
guards.
Note that the script is now able to handle all of these headers without
manual edits. =]
llvm-svn: 169224
This small change adds support for that. It will make all MCJIT tests pass
in make-check on BigEndian platforms.
Patch by Petar Jovanovic.
llvm-svn: 169178
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.
Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]
llvm-svn: 169131
The SectionMemoryManager now supports (and requires) applying section-specific page permissions. Clients using this memory manager must call either MCJIT::finalizeObject() or SectionMemoryManager::applyPermissions() before executing JITed code.
See r168718 for changes from the previous implementation.
llvm-svn: 168721
all symbols during object loading, not just global ones.
This fixes JIT execution of code using llvm.global_ctors with internal
linkage constructors.
llvm-svn: 168148
Prior to this patch RuntimeDyld attempted to re-apply relocations every time reassignSectionAddress was called (via MCJIT::mapSectionAddress). In addition to being inefficient and redundant, this led to a problem when a section was temporarily moved too far away from another section with a relative relocation referencing the section being moved. To fix this, I'm adding a new method (finalizeObject) which the client can call to indicate that it is finished rearranging section addresses so the relocations can safely be applied.
llvm-svn: 167400
Some ELF relocations require adding the a value to the original contents of the object buffer at the specified location. In order to properly handle multiple applications of a relocation, the RuntimeDyld code should be grabbing the original value from the object buffer and writing a new value into the loaded section buffer. This patch changes the parameters passed to resolveRelocations to accommodate this need.
llvm-svn: 167304
