Similar to -fprofile-generate=, add -fmemory-profile= which takes a
directory path. This is passed down to LLVM via a new module flag
metadata. LLVM in turn provides this name to the runtime via the new
__memprof_profile_filename variable.
Additionally, always pass a default filename (in $cwd if a directory
name is not specified vi the = form of the option). This is also
consistent with the behavior of the PGO instrumentation. Since the
memory profiles will generally be fairly large, it doesn't make sense to
dump them to stderr. Also, importantly, the memory profiles will
eventually be dumped in a compact binary format, which is another reason
why it does not make sense to send these to stderr by default.
Change the existing memprof tests to specify log_path=stderr when that
was being relied on.
Depends on D89086.
Differential Revision: https://reviews.llvm.org/D89087
This is consistent with the clang option added in
7ed8124d46, and the comments on the
runtime patch in D87120.
Differential Revision: https://reviews.llvm.org/D87622
See RFC for background:
http://lists.llvm.org/pipermail/llvm-dev/2020-June/142744.html
Note that the runtime changes will be sent separately (hopefully this
week, need to add some tests).
This patch includes the LLVM pass to instrument memory accesses with
either inline sequences to increment the access count in the shadow
location, or alternatively to call into the runtime. It also changes
calls to memset/memcpy/memmove to the equivalent runtime version.
The pass is modeled on the address sanitizer pass.
The clang changes add the driver option to invoke the new pass, and to
link with the upcoming heap profiling runtime libraries.
Currently there is no attempt to optimize the instrumentation, e.g. to
aggregate updates to the same memory allocation. That will be
implemented as follow on work.
Differential Revision: https://reviews.llvm.org/D85948
Teresa Johnson