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
This updates the instrumentation based profiling format so that when
we have multiple functions with the same name (but different function
hashes) we keep all of them instead of rejecting the later ones.
There are a number of scenarios where this can come up where it's more
useful to keep multiple function profiles:
* Name collisions in unrelated libraries that are profiled together.
* Multiple "main" functions from multiple tools built against a common
library.
* Combining profiles from different build configurations (ie, asserts
and no-asserts)
The profile format now stores the number of counters between the hash
and the counts themselves, so that multiple sets of counts can be
stored. Since this is backwards incompatible, I've bumped the format
version and added some trivial logic to skip this when reading the old
format.
llvm-svn: 214585
In some places we've been using different suffixes for the different
file formats involved in instrprof, but in others we've just
ambiguously used .profdata. Update the test files to indicate the
types of file more obviously.
No functional change.
llvm-svn: 214357
This moves some tests around to make it clearer what's being tested,
and adds very rudimentary comment syntax to the text input format to
make specifying this kind of test a little bit simpler.
llvm-svn: 214235
These are only used when the 'ld' in the path is gold and the plugin has
been built, but it is already a start to make sure we don't regress features
that cannot be tested with llvm-lto.
llvm-svn: 214058
This tool's job is to dump the vtables inside object files. It is
currently limited to MS ABI vf- and vb-tables but it will eventually
support Itanium-style v-tables as well.
Differential Revision: http://reviews.llvm.org/D4584
llvm-svn: 213903
The size of the uninitialized sections, like BSS, can exceed the size of
the object file.
Do not attempt to grab the contents of such sections.
llvm-svn: 212953
There were two issues here:
1. At the very least, scattered relocations cannot use the same code to
determine the corresponding symbol being referred to. For some reason we
pretend there is no symbol, even when one actually exists in the symtab, so to
match this behaviour getRelocationSymbol should simply return symbols_end for
scattered relocations.
2. Printing "-" when we can't get a symbol (including the scattered case, but
not exclusively), isn't that helpful. In both cases there *is* interesting
information in that field, so we should print it. As hex will do.
Small part of rdar://problem/17553104
llvm-svn: 212332
Make llvm-cov compatible with gcov for cases where multiple files are
specified on the command line. That is, loop over each one and report
coverage, and report errors on stderr only rather than via return
code.
llvm-svn: 211959
All tests in test/tools/llvm-cov fail on big-endian targets and are
supposed to be XFAILed there. However, including "powerpc64" in the
XFAIL line is now incorrect, since that matches both powerpc64- and
powerpc64le- targets, and the tests pass on the latter.
Update the XFAIL lines to use powerpc64- instead (like mips64-).
llvm-svn: 211172
Allow multiple raw profiles to coexist in a single .profraw file,
given the following conditions:
- Zero padding at the end of or between profiles will be skipped.
- Each profile must start with a valid header.
- Mixing endianness or pointer sizes in concatenated profiles files is
not allowed.
This is needed to handle cases where a program's shared libraries are
profiled as well as the main executable itself, as we'll need to emit
each executable's counters. Combining the tables in the runtime would
be expensive for the instrumented program.
rdar://16918688
llvm-svn: 208938
Tested by comparing make check VERBOSE=1 before and after to make sure
no tests are missed. (VERBOSE=1 prints the list of tests.)
Only one test :( remains where .cpp is required:
tools/llvm-cov/range_based_for.cpp:// RUN: llvm-cov range_based_for.cpp | FileCheck %s --check-prefix=STDOUT
The topic was discussed in this thread:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20140428/214905.html
llvm-svn: 208621
If the source files referenced by a gcno file are missing, gcov
outputs a coverage file where every line is simply /*EOF*/. This also
occurs for lines in the coverage that are past the end of a file that
is found.
This change mimics gcov.
llvm-svn: 208149
In gcov, there's a -n/--no-output option, which disables the writing
of any .gcov files, so that it emits only the summary info on stdout.
This implements the same behaviour in llvm-cov.
llvm-svn: 208148
Reading line tables in llvm-cov was pretty broken, but would happen to
work as long as no line in the table was 0. It's not clear to me
whether a line of zero *should* show up in these tables, but deciding
to read a string in the middle of the line table is certainly the
wrong thing to do if it does.
I've also added some comments, as trying to figure out what this block
of code was doing was fairly unpleasant.
llvm-svn: 207866
GCOV provides an option to prepend output file names with the source
file name, to disambiguate between covered data that's included from
multiple sources. Add a flag to llvm-cov that does the same.
llvm-svn: 207035
This adds support for an indexed instrumentation based profiling
format, which is just a small header and an on disk hash table. This
format will be used by clang's -fprofile-instr-use= for PGO.
llvm-svn: 206656
