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
There were two problems that made llvm-objdump -r crash:
- for non-scattered relocations, the symbol/section index is actually in the
(aptly named) symbolnum field.
- sections are 1-indexed.
llvm-svn: 181843
the things, and renames it to CBindingWrapping.h. I also moved
CBindingWrapping.h into Support/.
This new file just contains the macros for defining different wrap/unwrap
methods.
The calls to those macros, as well as any custom wrap/unwrap definitions
(like for array of Values for example), are put into corresponding C++
headers.
Doing this required some #include surgery, since some .cpp files relied
on the fact that including Wrap.h implicitly caused the inclusion of a
bunch of other things.
This also now means that the C++ headers will include their corresponding
C API headers; for example Value.h must include llvm-c/Core.h. I think
this is harmless, since the C API headers contain just external function
declarations and some C types, so I don't believe there should be any
nasty dependency issues here.
llvm-svn: 180881
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
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
Since the relocation iterator walks only the relocations in one section, we
can just use a pointer and avoid fetching information about the section at
every reference.
llvm-svn: 180262
getRelocationAddress is for dynamic libraries and executables,
getRelocationOffset for relocatable objects.
Mark the getRelocationAddress of COFF and MachO as not implemented yet. Add a
test of ELF's. llvm-readobj -r now prints the same values as readelf -r.
llvm-svn: 180259
While here, don't report a dummy symbol for relocations that don't have symbols.
We used to says such relocations were for the first defined symbol, but now we
return end_symbols(). The llvm-readobj output change agrees with otool.
llvm-svn: 180214
Since the relocation iterator walks only the relocations in one section, we
can just use a pointer and avoid fetching information about the section at
every reference.
llvm-svn: 180189
Thanks to Evgeniy Stepanov for reporting this.
It might be a good idea to add a command iterator abstraction to MachO.h, but
this fixes the bug for now.
llvm-svn: 179848
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
Original message:
Print more information about relocations.
With this patch llvm-readobj now prints if a relocation is pcrel, its length,
if it is extern and if it is scattered.
It also refactors the code a bit to use bit fields instead of shifts and
masks all over the place.
llvm-svn: 179345
With this patch llvm-readobj now prints if a relocation is pcrel, its length,
if it is extern and if it is scattered.
It also refactors the code a bit to use bit fields instead of shifts and
masks all over the place.
llvm-svn: 179294
It was returning the loaded address of the section containing the relocation,
which really doesn't seem to be the intent of this function.
llvm-svn: 179255
LoadCommandInfo was needed to keep a command and its offset in the file. Now
that we always have a pointer to the command, we don't need the offset.
llvm-svn: 178991
