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
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
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
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
Xinliang David Li