`DataAggregator::recordTrace` serves two purposes:
- Attaching LBR fallthrough ("trace") information to CFG (`getBranchInfo`),
which eventually gets emitted as YAML profile.
- Populating vector of offsets that gets added to `FuncBranchData`, which
eventually gets emitted as fdata profile.
`recordTrace` is invoked from `getFallthroughsInTrace` which checks its return
status and passes on the collected vector of offsets to `doTrace`.
However, if a malformed trace is passed to `recordTrace` it might partially
attach the profile to CFG and exit with false, not propagating the vector of
offsets to `doTrace`. This leads to a difference between fdata and yaml profile
collected from the same binary and the same perf file.
(Skylake LBR errata might produce such malformed traces where the last entry
is duplicated, resulting in invalid fallthrough path between the last two
entries).
There are two ways to handle this mismatch: conservative (aligned with fdata),
or aggressive (aligned with yaml). Conservative approach would discard the
trace entirely, buffering the CFG updates until all fallthroughs are confirmed.
Aggressive approach would apply CFG updates and return the matching
fallthroughs in the vector even if the trace is invalid (doesn't correspond to
a valid fallthrough path). I chose to go with the former (conservative/fdata)
approach which produces more accurate profile.
We can't rely on pre-filtering such traces early (in LBR sample processing) as
DataAggregator is used for both perf samples and pre-aggregated perf information
which loses branch stack information.
Test Plan: https://github.com/rafaelauler/bolt-tests/pull/22
Reviewed By: #bolt, rafauler
Differential Revision: https://reviews.llvm.org/D151614
The existing BOLT install targets are broken on Windows becase they
don't properly handle output extension. Rather than reimplementing
this logic in BOLT, reuse the existing LLVM macros which already
handle this aspect correctly.
Differential Revision: https://reviews.llvm.org/D151595
This reverts commit d763c6e5e2d0a6b34097aa7dabca31e9aff9b0b6.
Adds the patch by @hans from
https://github.com/llvm/llvm-project/issues/62719
This patch fixes the Windows build.
d763c6e5e2d0a6b34097aa7dabca31e9aff9b0b6 reverted the reviews
D144509 [CMake] Bumps minimum version to 3.20.0.
This partly undoes D137724.
This change has been discussed on discourse
https://discourse.llvm.org/t/rfc-upgrading-llvms-minimum-required-cmake-version/66193
Note this does not remove work-arounds for older CMake versions, that
will be done in followup patches.
D150532 [OpenMP] Compile assembly files as ASM, not C
Since CMake 3.20, CMake explicitly passes "-x c" (or equivalent)
when compiling a file which has been set as having the language
C. This behaviour change only takes place if "cmake_minimum_required"
is set to 3.20 or newer, or if the policy CMP0119 is set to new.
Attempting to compile assembly files with "-x c" fails, however
this is workarounded in many cases, as OpenMP overrides this with
"-x assembler-with-cpp", however this is only added for non-Windows
targets.
Thus, after increasing cmake_minimum_required to 3.20, this breaks
compiling the GNU assembly for Windows targets; the GNU assembly is
used for ARM and AArch64 Windows targets when building with Clang.
This patch unbreaks that.
D150688 [cmake] Set CMP0091 to fix Windows builds after the cmake_minimum_required bump
The build uses other mechanism to select the runtime.
Fixes#62719
Reviewed By: #libc, Mordante
Differential Revision: https://reviews.llvm.org/D151344
This is an ongoing series of commits that are reformatting our
Python code. This catches the last of the python files to
reformat. Since they where so few I bunched them together.
Reformatting is done with `black`.
If you end up having problems merging this commit because you
have made changes to a python file, the best way to handle that
is to run git checkout --ours <yourfile> and then reformat it
with black.
If you run into any problems, post to discourse about it and
we will try to help.
RFC Thread below:
https://discourse.llvm.org/t/rfc-document-and-standardize-python-code-style
Reviewed By: jhenderson, #libc, Mordante, sivachandra
Differential Revision: https://reviews.llvm.org/D150784
D151036 adds an assertions that prohibits iterating over sub- and
super-registers of a null register. This is already the case when
iterating over register units of a null register, and worked by
accident for sub- and super-registers.
Reviewed By: Amir
Differential Revision: https://reviews.llvm.org/D151285
Resovled the issue that when number of tasks is fewer than cores, we end
up creating as many threads as the number of cores, making the
performance worse than the single thread version.
PUSH[16|32|64]i[8|32] are not arithmetic instructions, so I renamed the
functions.
Reviewed By: Amir
Differential Revision: https://reviews.llvm.org/D151028
Add helper methods and simplify cases where we want to check if two functions
are parent-child of each other (function-fragment relationship).
Reviewed By: #bolt, rafauler
Differential Revision: https://reviews.llvm.org/D142668
This reverts commit 65429b9af6a2c99d340ab2dcddd41dab201f399c.
Broke several projects, see https://reviews.llvm.org/D144509#4347562 onwards.
Also reverts follow-up commit "[OpenMP] Compile assembly files as ASM, not C"
This reverts commit 4072c8aee4c89c4457f4f30d01dc9bb4dfa52559.
Also reverts fix attempt "[cmake] Set CMP0091 to fix Windows builds after the cmake_minimum_required bump"
This reverts commit 7d47dac5f828efd1d378ba44a97559114f00fb64.
We have mostly harmless data races when running
BinaryContext::calculateEmittedSize() in parallel, while performing
split function pass. However, it is possible to end up in a state
where some MCSymbols are still registered and our clean up
failed. This happens rarely but it does happen, and when it happens,
it is a difficult to diagnose heisenbug. To avoid this, add a new
clean pass to perform a last check on MCSymbols, before they
undergo our final emission pass, to verify that they are in a sane
state. If we fail to do this, we might resolve some symbols to zero
and crash the output binary.
Reviewed By: #bolt, Amir
Differential Revision: https://reviews.llvm.org/D137984
find_section used to match offsets equal to file_offset + size causing
offsets to sometimes be attributed to the wrong section.
Reviewed By: Amir
Differential Revision: https://reviews.llvm.org/D149047
Spotted this one while working on new DWARF Rewriter. We were using wrong check
in assertion.
Reviewed By: Amir
Differential Revision: https://reviews.llvm.org/D150167
Use MCInst opcode name instead of opcode value in hashing.
Opcode values are unstable wrt changes to target tablegen definitions,
and we notice that as output mismatches in NFC testing. This makes BOLT YAML
profile tied to a particular LLVM revision which is less portable than
offset-based fdata profile.
Switch to using opcode names which have 1:1 mapping with opcode values for any
given LLVM revision, and are stable wrt modifications to .td files (except of
course modifications to names themselves).
Test Plan:
D150154 is a test commit adding new X86 instruction which shifts opcode values.
With current change, pre-aggregated-perf.test passes in nfc check mode.
Without current change, pre-aggregated-perf.test expectedly fails.
Reviewed By: #bolt, rafauler
Differential Revision: https://reviews.llvm.org/D150005
Make retpoline functions invariant of X86 register numbers.
retpoline-synthetic.test is known to fail NFC testing due to shifting
register numbers. Use canonical register names instead of tablegen
numbers.
Before:
```
__retpoline_r51_
__retpoline_mem_r58+DATAat0x200fe8
__retpoline_mem_r51+0
__retpoline_mem_r132+0+8*53
```
After:
```
__retpoline_%rax_
__retpoline_mem_%rip+DATAat0x200fe8
__retpoline_mem_%rax+0
__retpoline_mem_%r12+0+8*%rbx
```
Test Plan:
- Revert 67bd3c58c0c7389e39c5a2f4d3b1a30459ccf5b7 that touches X86RegisterInfo.td.
- retpoline-synthetic.test passes in NFC mode with this diff, fails without it.
Reviewed By: #bolt, rafauler
Differential Revision: https://reviews.llvm.org/D150138
They don't convey any useful information and make the documentation
unnecessarily hard to read.
Differential Revision: https://reviews.llvm.org/D149641
There are CUs that have DW_AT_loclists_base, but no DW_AT_location in children
DIEs. Pre-bolt it points to a valid offset. We were not updating it, so it ended
up pointing in the middle of a list and caused LLDB to print out errors. Changed
it to point to first location list. I don't think it should matter since there
are no accesses to it anyway.
Reviewed By: maksfb
Differential Revision: https://reviews.llvm.org/D149798
Extending yaml profile format with block hashes, which are used for stale
profile matching. To avoid duplication of the code, created a new class with a
collection of utilities for computing hashes.
Reviewed By: Amir
Differential Revision: https://reviews.llvm.org/D144306
For empty sections, RuntimeDyld always allocates 1 byte but leaves it
uninitialized. This causes the contents of some output sections to be
non-deterministic.
Note that this issue is also solved by D147544.
Fixes#59008
Reviewed By: maksfb
Differential Revision: https://reviews.llvm.org/D149243
The byte offsets in the output of 'cmp' start from 1, not from 0 as the
current parser assumes. This caused mismatched bytes to sometimes be
attributed to the wrong section.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D149046
Since D148847, many tests are detected as being unsupported. This is
caused by BOLT_TARGETS_TO_BUILD being ;-separated whereas the previously
used TARGETS_TO_BUILD is space-separated.
This patch fixes this by creating config.targets lit.cfg.py by splitting
on ';'.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D149026
This commit splits the generic part of `LoopInfo` into separate files.
These new `GenericLoopInfo` files are located in `llvm/Support` to be inline
with `GenericDomTree`.
Furthermore, this change ensures that MLIR's Bazel build does not have
to link against `LLVMAnalysis` just to use these template headers.
Depends on D148219
Reviewed By: ftynse
Differential Revision: https://reviews.llvm.org/D148235
These checks are unnecessary -- we've already bailed if the format was wrong.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D148848
Adds BOLT_TARGETS_TO_BUILD, which defaults to the intersection of
X86;AArch64 and LLVM_TARGETS_TO_BUILD, but allows configuration to
alter that -- for instance omitting one of those two targets even if
llvm supports both.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D148847
The BOLT runtime is specifically hard coded for x86_64 linux or x86_64
darwin. (Using x86_64 syscalls, hardcoding syscall numbers.)
Make it very clear this is for those specific pair of systems.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D148825
Defaults to ON for x86_64 && (Linux | Darwin).
If enabled, checks that /proc/self/map_files is readable. Some systems are configured so that getdents fails with EPERM.
Reviewed By: rafauler
Differential Revision: https://reviews.llvm.org/D148742
This typedef is only used inside the RewriteInstance source file, let's not
expose it in the header file -- even if private.
Differential Revision: https://reviews.llvm.org/D148667
Shdr's are not necesarily size 2^n, and there is no reason to align to
that boundary if they are.
Differential Revision: https://reviews.llvm.org/D148666
