Teach WinCOFFObjectWriter how to write -mbig-obj style object files;
these object files allow for more sections inside an object file.
Our support for BigObj is notably different from binutils and cl: we
implicitly upgrade object files to BigObj instead of asking the user to
compile the same file *again* but with another flag. This matches up
with how LLVM treats ELF variants.
This was tested by forcing LLVM to always emit BigObj files and running
the entire test suite. A specific test has also been added.
I've lowered the maximum number of sections in a normal COFF file,
VS "14" CTP 3 supports no more than 65279 sections. This is important
otherwise we might not switch to BigObj quickly enough, leaving us with
a COFF file that we couldn't link.
yaml2obj support is all that remains to implement.
Differential Revision: http://reviews.llvm.org/D5349
llvm-svn: 217812
This adds support for reading the "bigobj" variant of COFF produced by
cl's /bigobj and mingw's -mbig-obj.
The most significant difference that bigobj brings is more than 2**16
sections to COFF.
bigobj brings a few interesting differences with it:
- It doesn't have a Characteristics field in the file header.
- It doesn't have a SizeOfOptionalHeader field in the file header (it's
only used in executable files).
- Auxiliary symbol records have the same width as a symbol table entry.
Since symbol table entries are bigger, so are auxiliary symbol
records.
Write support will come soon.
Differential Revision: http://reviews.llvm.org/D5259
llvm-svn: 217496
Owning the buffer is somewhat inflexible. Some Binaries have sub Binaries
(like Archive) and we had to create dummy buffers just to handle that. It is
also a bad fit for IRObjectFile where the Module wants to own the buffer too.
Keeping this ownership would make supporting IR inside native objects
particularly painful.
This patch focuses in lib/Object. If something elsewhere used to own an Binary,
now it also owns a MemoryBuffer.
This patch introduces a few new types.
* MemoryBufferRef. This is just a pair of StringRefs for the data and name.
This is to MemoryBuffer as StringRef is to std::string.
* OwningBinary. A combination of Binary and a MemoryBuffer. This is needed
for convenience functions that take a filename and return both the
buffer and the Binary using that buffer.
The C api now uses OwningBinary to avoid any change in semantics. I will start
a new thread to see if we want to change it and how.
llvm-svn: 216002
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
Now that we have a lib/MC/MCAnalysis, the dependency was there just because
of two helper classes. Move the two over to MC.
This will allow IRObjectFile to parse inline assembly.
llvm-svn: 212248
This code was never being used and any use of it would look fairly strange.
For example, it would try to map a object_error::parse_failed to
std::errc::invalid_argument.
llvm-svn: 210912
The idea of this patch is to turn llvm/Support/system_error.h into a
transitional header that just brings in the erorr_code api to the llvm
namespace. I will remove it shortly afterwards.
The cases where the general idea needed some tweaking:
* std::errc is a namespace in msvc, so we cannot use "using std::errc". I could
add an #ifdef, but there were not that many uses, so I just added std:: to
them in this patch.
* Template specialization had to be moved to the std namespace in this
patch set already.
* The msvc implementation of default_error_condition doesn't seem to
provide the same transformations as we need. Not too surprising since
the standard doesn't actually say what "equivalent" means. I fixed the
problem by keeping our old mapping and using it at error_code
construction time.
Despite these shortcomings I think this is still a good thing. Some reasons:
* The different implementations of system_error might improve over time.
* It removes 925 lines of code from llvm already.
* It removes 6313 bytes from the text segment of the clang binary when
it is built with gcc and 2816 bytes when building with clang and
libstdc++.
llvm-svn: 210687
field represents ELF section header sh_info field and does not have any
sense for regular sections. Its interpretation depends on section type.
llvm-svn: 209801
Now the only method to configure ELF section's content and size is to assign
a hexadecimal string to the `Content` field. Unfortunately this way is
completely useless when you need to declare a really large section.
To solve this problem this patch adds one more optional field `Size`
to the `RawContentSection` structure. When yaml2obj generates an ELF file
it uses the following algorithm:
1. If both `Content` and `Size` fields are missed create an empty section.
2. If only `Content` field is missed take section length from the `Size`
field and fill the section by zero.
3. If only `Size` field is missed create a section using data from
the `Content` field.
4. If both `Content` and `Size` fields are provided validate that the `Size`
value is not less than size of `Content` data. Than take section length
from the `Size`, fill beginning of the section by `Content` and the rest
by zero.
Examples
--------
* Create a section 0x10000 bytes long filled by zero
Name: .data
Type: SHT_PROGBITS
Flags: [ SHF_ALLOC ]
Size: 0x10000
* Create a section 0x10000 bytes long starting from 'CA' 'FE' 'BA' 'BE'
Name: .data
Type: SHT_PROGBITS
Flags: [ SHF_ALLOC ]
Content: CAFEBABE
Size: 0x10000
The patch reviewed by Michael Spencer.
llvm-svn: 208995
The ELF header e_flags field in the MIPS related test cases handled
incorrectly. The obj2yaml prints too many flags. I will fix that in the
next patches.
The patch reviewed by Michael Spencer and Sean Silva.
llvm-svn: 208752
interface methods isCOFF().
The '-coff' command line option has been removed. It was not used in any
test cases.
The patch reviewed by Michael Spencer.
llvm-svn: 208157
The current state of affairs has auxiliary symbols described as a big
bag of bytes. This is less than satisfying, it detracts from the YAML
file as being human readable.
Instead, allow for symbols to optionally contain their auxiliary data.
This allows us to have a much higher level way of describing things like
weak symbols, function definitions and section definitions.
This depends on D3105.
Differential Revision: http://llvm-reviews.chandlerc.com/D3092
llvm-svn: 204214
This compiles with no changes to clang/lld/lldb with MSVC and includes
overloads to various functions which are used by those projects and llvm
which have OwningPtr's as parameters. This should allow out of tree
projects some time to move. There are also no changes to libs/Target,
which should help out of tree targets have time to move, if necessary.
llvm-svn: 203083
None of the object file formats reported error on iterator increment. In
retrospect, that is not too surprising: no object format stores symbols or
sections in a linked list or other structure that requires chasing pointers.
As a consequence, all error checking can be done on begin() and end().
This reduces the text segment of bin/llvm-readobj in my machine from 521233 to
518526 bytes.
llvm-svn: 200442
These records are mandatory for executables and are used by the loader.
Reviewers: rafael
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D939
llvm-svn: 183852
This is part of a future patch to use yamlio that incorrectly ended up in a
cleanup patch.
Thanks to Benjamin Kramer for reporting it.
llvm-svn: 179938
David Majnemer