This format is simply a regular object file with the bitcode stored in a
section named ".llvmbc", plus any number of other (non-allocated) sections.
One immediate use case for this is to accommodate compilation processes
which expect the object file to contain metadata in non-allocated sections,
such as the ".go_export" section used by some Go compilers [1], although I
imagine that in the future we could consider compiling parts of the module
(such as large non-inlinable functions) directly into the object file to
improve LTO efficiency.
[1] http://golang.org/doc/install/gccgo#Imports
Differential Revision: http://reviews.llvm.org/D4371
llvm-svn: 218078
First step done in this commit is to get flush out enough of the
SymbolizerGetOpInfo() routine to symbolic an X86_64 hello world .o and
its loading of the literal string and call to printf. Also the code to
symbolicate the X86_64_RELOC_SUBTRACTOR relocation and a test is also
added to show a slightly more complicated case.
Next will be to flush out enough of SymbolizerSymbolLookUp() to get the
literal string “Hello world” printed as a comment on the instruction that load
the pointer to it.
llvm-svn: 217893
Teach yaml2obj how to make a bigobj COFF file. Like the rest of LLVM,
we automatically decide whether or not to use regular COFF or bigobj
COFF on the fly depending on how many sections the resulting object
would have.
This ends the task of adding bigobj support to LLVM.
N.B. This was tested by forcing yaml2obj to be used in bigobj mode
regardless of the number of sections. While a dedicated test was
written, the smallest I could make it was 36 MB (!) of yaml and it still
took a significant amount of time to execute on a powerful machine.
llvm-svn: 217858
This finishes the ability of llvm-objdump to print out all information from
the LC_DYLD_INFO load command.
The -bind option prints out symbolic references that dyld must resolve
immediately.
The -lazy-bind option prints out symbolc reference that are lazily resolved on
first use.
The -weak-bind option prints out information about symbols which dyld must
try to coalesce across images.
llvm-svn: 217853
This changes the debug output of the llvm-cov tool to consistently
write to stderr, and moves the highlighting output closer to where
it's relevant.
llvm-svn: 217838
In r217746, though it was supposed to be NFC, I broke llvm-cov's
handling of showing regions without showing counts. This should've
shown up in the existing tests, except they were checking debug output
that was displayed regardless of what was actually output. I've moved
the relevant debug output to a more appropriate place so that the
tests catch this kind of thing.
llvm-svn: 217835
Similar to my previous -exports-trie option, the -rebase option dumps info from
the LC_DYLD_INFO load command. The rebasing info is a list of the the locations
that dyld needs to adjust if a mach-o image is not loaded at its preferred
address. Since ASLR is now the default, images almost never load at their
preferred address, and thus need to be rebased by dyld.
llvm-svn: 217709
The raw profiles that are generated in compiler-rt always add padding
so that each profile is aligned, so we can simply treat files that
don't have this property as malformed.
Caught by Alexey's new ubsan bot. Thanks!
llvm-svn: 217708
This fixes a call to sys::fs::equivalent that should've been to
CodeCoverageTool::equivalentFiles, which lets us restore the test of
r217476 that was removed in r217478.
This reverts r217478, but the test works this time.
llvm-svn: 217646
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
It appears that the -filename-equivalence option for testing llvm-cov
doesn't work correctly with -show-expansions. I'm reverting this test
to get the bots green while I look into fixing that.
This partially reverts r217476
llvm-svn: 217478
This is the plugin version of pr20882.
This handles the case of every common symbol being in the IR. We will need some
support from gold to handle the case where some symbols are in ELF and some in
the IR.
llvm-svn: 217458
MachOObjectFile in lib/Object currently has no support for parsing the rebase,
binding, and export information from the LC_DYLD_INFO load command in final
linked mach-o images. This patch adds support for parsing the exports trie data
structure. It also adds an option to llvm-objdump to dump that export info.
I did the exports parsing first because it is the hardest. The information is
encoded in a trie structure, but the standard ObjectFile way to inspect content
is through iterators. So I needed to make an iterator that would do a
non-recursive walk through the trie and maintain the concatenation of edges
needed for the current string prefix.
I plan to add similar support in MachOObjectFile and llvm-objdump to
parse/display the rebasing and binding info too.
llvm-svn: 216808
There are two parts to this. First, the plugin needs to tell gold the comdat by
setting comdat_key.
What gets things a bit more complicated is that gold only seems
symbols. In particular, if A is an alias to B, it only sees the symbols
A and B. It can then ask us to keep symbol A but drop symbol B. What
we have to do instead is to create an internal version of B and make A
an alias to that.
At some point some of this logic should be moved to lib/Linker so that
we don't map a Constant to an internal version just to have lib/Linker
map that again to the destination module.
The reason for implementing this in tools/gold for now is simplicity.
With it in place it should be possible to update clang to use comdats
for constructors and destructors on ELF without breaking the LTO
bootstrap. Once that is done I intend to come back and improve the
interface lib/Linker exposes.
llvm-svn: 216302
This commit expands llvm-cov's functionality by adding support for a new code coverage
tool that uses LLVM's coverage mapping format and clang's instrumentation based profiling.
The gcov compatible tool can be invoked by supplying the 'gcov' command as the first argument,
or by modifying the tool's name to end with 'gcov'.
Differential Revision: http://reviews.llvm.org/D4445
llvm-svn: 216300
There is a fundamental difference between how the gold API and lib/LTO view
the LTO process.
The gold API talks about a particular symbol in a particular file. The lib/LTO
API talks about a symbol in the merged module.
The merged module is then defined in terms of the IR semantics. In particular,
a linkonce_odr GV is only copied if it is used, since it is valid to drop
unused linkonce_odr GVs.
In the testcase in pr19901 both properties collide. What happens is that gold
asks us to keep a particular linkonce_odr symbol, but the IR linker doesn't
copy it to the merged module and we never have a chance to ask lib/LTO to keep
it.
This patch fixes it by having a more direct implementation of the gold API. If
it asks us to keep a symbol, we change the linkage so it is not linkonce. If it
says we can drop a symbol, we do so. All of this before we even send the module
to lib/Linker.
Since now we don't have to produce LTO_SYMBOL_SCOPE_DEFAULT_CAN_BE_HIDDEN,
during symbol resolution we can use a temporary LLVMContext and do lazy
module loading. This allows us to keep the minimum possible amount of
allocated memory around. This should also allow as much parallelism as
we want, since there is no shared context.
llvm-svn: 216215
file with -macho, the Mach-O specific object file parser option.
After some discussion I chose to do this implementation contained in the logic
of llvm-objdump’s MachODump.cpp using a second disassembler for thumb when
needed and with updates mostly contained in the MachOObjectFile class.
llvm-svn: 215931
I initially thought I could implement COMDATs with aliases by just
internalizing GVs instead of dropping them. This is a counter
example: Internalizing one of the @a would make @b and @c point
to different variables.
llvm-svn: 215447
The timestamp meant these files changed with each invocation of
relocs.py, confusing matters when we add relocations and need to
update the tests.
llvm-svn: 215350
Also make the disassembler created with the Mach-O parser (the -m option)
pick up the Target specific attributes specified with -mattr option.
llvm-svn: 215032
