These are identified by misc-include-cleaner. I've filtered out those
that break builds. Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.
Re-apply https://github.com/llvm/llvm-project/pull/139997 after fixing the use-of-uninitialized-memory error
(https://lab.llvm.org/buildbot/#/builders/94/builds/7373).
Tested: The error is reproduced with
https://github.com/llvm/llvm-zorg/blob/main/zorg/buildbot/builders/sanitizers/buildbot_bootstrap_msan.sh
without the fix, and test pass with the fix.
**Original commit message:**
https://github.com/llvm/llvm-project/pull/138170 introduces classes to
operate on data access profiles. This change supports the read and write
of `DataAccessProfData` in indexed format of MemProf (v4) as well as its
the text (yaml) format.
For indexed format:
* InstrProfWriter owns (by `std::unique_ptr<DataAccessProfData>`) the
data access profiles, and gives a non-owned copy when it calls
`writeMemProf`.
* MemProf v4 header has a new `uint64_t` to record the byte offset of
data access profiles. This `uint64_t` field is zero if data access
profile is not set (nullptr).
* MemProfReader reads the offset from v4 header and de-serializes
in-memory bytes into class `DataAccessProfData`.
For textual format:
* MemProfYAML.h adds the mapping for DAP class, and make DAP optional
for both read and write.
099a0fa (by @snehasish) introduces v4 which contains CalleeGuids in
CallSiteInfo, and this change changes the v4 format in place with data
access profiles. The current plan is to bump the version and enable v4
profiles with both features, assuming waiting for this change won't
delay the callsite change too long.
---------
Co-authored-by: Kazu Hirata <kazu@google.com>
https://github.com/llvm/llvm-project/pull/138170 introduces classes to
operate on data access profiles. This change supports the read and write
of `DataAccessProfData` in indexed format of MemProf (v4) as well as its
the text (yaml) format.
For indexed format:
* InstrProfWriter owns (by `std::unique_ptr<DataAccessProfData>`) the
data access profiles, and gives a non-owned copy when it calls
`writeMemProf`.
* MemProf v4 header has a new `uint64_t` to record the byte offset of
data access profiles. This `uint64_t` field is zero if data access
profile is not set (nullptr).
* MemProfReader reads the offset from v4 header and de-serializes
in-memory bytes into class `DataAccessProfData`.
For textual format:
* MemProfYAML.h adds the mapping for DAP class, and make DAP optional
for both read and write.
099a0fa (by @snehasish) introduces v4 which contains CalleeGuids in
CallSiteInfo, and this change changes the v4 format in place with data
access profiles. The current plan is to bump the version and enable v4
profiles with both features, assuming waiting for this change won't
delay the callsite change too long.
---------
Co-authored-by: Kazu Hirata <kazu@google.com>
Context: For
https://discourse.llvm.org/t/rfc-profile-guided-static-data-partitioning/83744#p-336543-background-3,
we propose to profile memory loads and stores via hardware events,
symbolize the addresses of binary static data sections and feed the
profile back into compiler for data partitioning.
This change adds the profile format for static data layout, and the
classes to operate on it.
The profile and its format
1. Conceptually, a piece of data (call it a symbol) is represented by
its symbol name or its content hash. The former applies to majority of
data whose mangled name remains relatively stable over binary releases,
and the latter applies to string literals (with name patterns like
`.str.<N>[.llvm.<hash>]`.
- The symbols with samples are hot data. The number of hot symbols is
small relative to all symbols. The profile tracks its sampled counts and
locations. Sampled counts come from hardware events, and locations come
from debug information in the profiled binary. The symbols without
samples are cold data. The number of such cold symbols is large. The
profile tracks its representation (the name or content hash).
- Based on a preliminary study, debug information coverage for data
symbols is partial and best-effort. In the LLVM IR, global variables
with source code correspondence may or may not have debug information.
Therefore the location information is optional in the profiles.
2. The profile-and-compile cycle is similar to SamplePGO. Profiles are
sampled from production binaries, and used in next binary releases.
Known cold symbols and new hot symbols can both have zero sampled
counts, so the profile records known cold symbols to tell the two for
next compile.
In the profile's serialization format, strings are concatenated together
and compressed. Individual records stores the index.
A separate PR will connect this class to InstrProfReader/Writer via
MemProfReader/Writer.
---------
Co-authored-by: Kazu Hirata <kazu@google.com>
