On Darwin, compiler_rt uses magic linker symbols to find the profile
counters in the __DATA segment. This is a reasonable method for
normal, hosted, userspace programs. However programs with custom
memory layouts, such as the kernel, will need to tell compiler_rt
explicitly where to find these sections.
Patch by Lawrence D'Anna. Thanks!
llvm-svn: 223840
This change removes libclang_rt.profile-pic-<arch>.a version of
profile runtime. Instead, it's sufficient to always build
libclang_rt.profile-<arch>.a with -fPIC, as it can be linked into
both executables and shared objects.
llvm-svn: 221952
The naming scheme we're using for counters in profile data shares a
prefix with some fixed names we use for the runtime, notably
__llvm_profile_data_begin and _end. Embarrassingly, this means a
function called begin() can't be instrumented.
This modifies the runtime names so as not to collide with the
instrumentation.
llvm-svn: 217166
Shared objects are hard. After this commit, we do the right thing when
profiling two separate shared objects that have been dlopen'd with
`RTLD_LOCAL`, when the main executable is *not* being profiled.
This mainly simplifies the writer logic.
- At initialization, determine the output filename and truncate the
file. Depending on whether shared objects can see each other, this
may happen multiple times.
- At exit, each executable writes its own profile in append mode.
<rdar://problem/16918688>
llvm-svn: 209053
These tests were XPASS-ing on Linux bots creating Mach-O, which makes
sense, since the real difference is the object format.
I'm hoping a short-term fix to get these tests passing on ELF is to
create two copies of the runtime -- one built with -fPIC, and one
without. A follow-up patch will change clang's driver to pick between
them depending on whether `-shared` is specified.
llvm-svn: 208947
Change the API of the instrumented profiling library to work with shared
objects.
- Most things are now declared hidden, so that each executable gets
its own copy.
- Initialization hooks up a linked list of writers.
- The raw format with shared objects that are profiled consists of a
concatenated series of profiles. llvm-profdata knows how to deal
with that since r208938.
<rdar://problem/16918688>
llvm-svn: 208940
GCC -pedantic warns that the initialization of Header is not constant:
InstrProfilingFile.c:31:5: error: initializer element is not computable at load time [-Werror]
LLVM defaults to enabling -pedantic. If this warning is unhelpful, we
can consider revisiting that decision.
llvm-svn: 207784
Add the test infrastructure for testing lib/profile and a single test.
This initial commit only enables the tests on Darwin, but they'll be
enabled on Linux soon after.
<rdar://problem/16458307>
llvm-svn: 205256
Soon there will be an option to build compiler-rt parts as shared libraries
on Linux. Extracted from http://llvm-reviews.chandlerc.com/D3042
by Yuri Gribov.
llvm-svn: 205183
Change the name of the default profile dumped by compiler-rt to
default.profraw. This distinguishes it more clearly from the
(incompatible) format output by llvm-profdata that is read by clang
-fprofile-instr-use.
llvm-svn: 204676
Since the profile can come from 32-bit machines, the reader needs to
check the pointer size. Change the magic number to facilitate this.
<rdar://problem/16400648>
llvm-svn: 204556
This is a bit of a stab in the dark as I'm not sure I've got these
source files compiling correctly locally. (and the warning only
reproduces on a 32bit build anyway)
llvm-svn: 204521
Apparently, MSVC has stdint.h now? Let's see if the buildbots complain.
I'm not convinced that the build system is even set up for MSVC to build
this file, but...
llvm-svn: 204515
Write __llvm_profile_write_buffer(), which uses the same logic as
__llvm_profile_write_file(), but writes directly to a provided `char*`
buffer instead.
<rdar://problem/15943240>
llvm-svn: 204499
It was misguided to plan to rely on __llvm_profile_write_buffer() in
__llvm_profile_write_file(). It's less complex to duplicate the writing
logic than to mmap the file.
Since it's here to stay, move `FILE*`-based writing logic into
InstrProfilingFile.c.
<rdar://problem/15943240>
llvm-svn: 204498
Move functions around to prepare for some other changes.
- Merge InstrProfilingExtras.h with InstrProfiling.h. There's no
benefit to having these split.
- Rename InstrProfilingExtras.c to InstrProfilingFile.c.
- Split actual buffer writing code out of InstrProfiling.c into
InstrProfilingBuffer.c.
- Drive-by corrections of a couple of header comments.
<rdar://problem/15943240>
llvm-svn: 204497
Add logic to do a printf-style substitution of %p for the process pid in
the filename.
It's getting increasingly awkward to work on lib/profile without test
infrastructure. This needs to be fixed!
<rdar://problem/16383358>
llvm-svn: 204414
These functions are in the profile runtime. PGO comes later.
Unfortunately, there's only room for 16 characters in a Darwin section,
so use __llvm_prf_ instead of __llvm_profile_ for section names.
<rdar://problem/15943240>
llvm-svn: 204391
__llvm_pgo_write_default_file() was a bad name, since it checked the
environment (it wasn't just a default file).
- Change __llvm_pgo_write_file() to __llvm_pgo_write_file_with_name()
and make it static.
- Rename __llvm_pgo_write_default_file() to __llvm_pgo_write_file().
- Add __llvm_pgo_set_filename(), which sets the filename for
subsequent calls to __llvm_pgo_write_file().
<rdar://problem/15943240>
llvm-svn: 204381
Instead of relying on explicit static initialization from translation
units, create a new file, InstrProfilingRuntime.cc, with an
__llvm_pgo_runtime variable. After this commit (and its pair in clang),
the driver will create a use of this variable. Unless the user defines
their own version, the new object file will get pulled in, including
that C++ static initialization that calls
__llvm_pgo_register_write_atexit.
The result is that, at least on Darwin, static initialization typically
consists of a single function call, which registers a writeout functino
atexit. Furthermore, users can skip even this behaviour by defining
their own __llvm_pgo_runtime.
<rdar://problem/15943240>
llvm-svn: 204380
Currently we register instrumentation data at runtime to determine the
bounds of the sections where the data lives. Soon we'll implement
platform-specific linker magic to determine this at link time.
Move this logic to a separate file, so that our build system can choose
the correct platform-specific code.
No functionality change intended.
<rdar://problem/15943240>
llvm-svn: 204299
Split implementation files along a uses-libc/shouldn't-use-libc
boundary.
- InstrProfiling.h is a shared header.
- InstrProfiling.c provides an API to extract profiling data from the
runtime, but avoids the use of libc. Currently this is a lie:
__llvm_pgo_write_buffer() uses `FILE*` and related functions. It
will be updated soon to write to a `char*` buffer instead.
- InstrProfilingExtras.c provides a more convenient API for
interfacing with the profiling runtime, but has logic that does (and
will continue to) use libc.
<rdar://problem/15943240>
llvm-svn: 204268
In instrumentation-based profiling, we need a set of data structures to
represent the counters. Previously, these were built up during static
initialization. Now, they're shoved into a specially-named section so
that they show up as an array.
As a consequence of the reorganizing symbols, instrumentation data
structures for linkonce functions are now correctly coalesced.
This is the first step in a larger project to minimize runtime overhead
and dependencies in instrumentation-based profilng. The larger picture
includes removing all initialization overhead and making the dependency
on libc optional.
<rdar://problem/15943240>
llvm-svn: 204079
This will break without the corresponding change in clang, which I've
reverted until I figure out how to get it to link properly.
This reverts commit r203710.
llvm-svn: 203713
Justin Bogner