Summary:
Since gcc/ld could produce and expect PIE files we need to pass -no-pie option to avoid linking errors for tests.
Vladislav Khmelevsky,
Advanced Software Technology Lab, Huawei
(cherry picked from FBD28360045)
Summary:
Reorder-blocks optimization pass doesn't take into account that
available offset for legacy Jcc instructions (for example,
JRCXZ - operand 8 bits) has to be less than 255 bytes.
It's rare case and to exclude such functions with unsupported
instructions from optimization passes added extra checking
Alexey Moksyakov
Advanced Software Technology Lab, Huawei
(cherry picked from FBD28264117)
Summary:
Ran iwyu multiple times, manually picked header remove lines.
Reached fixed point wrt removal: iwyu doesn't automatically remove
any more headers or forward declarations.
(cherry picked from FBD29569221)
Summary:
Previously, we used p_align value of the code segment to predict the
mapping of the segment at runtime. However, at times the reported
value is not aligned and at other times the actual aligned value will
be different because of the different page size used.
All we know is that the page size used at runtime should not exceed
p_align value. Adjust our segment address matching accordingly.
(cherry picked from FBD28133066)
Summary:
Addressing comments from the review for "Expand auto types".
Use const reference in MCPlusBuilder for MCInstrDesc where the copy
is not necessary.
(cherry picked from FBD27844344)
Summary:
We may have a CU with empty ranges, so accept errors coming
from DWARFDie::getAddressRanges(). This happens when using tools that
selectively strip debuginfo from the binary.
(cherry picked from FBD27602731)
Summary:
Refactor SectionPatches to avoid the use of extra map and a cast
from StringRef to std::string.
cherry-picked from FBD26756560
(cherry picked from FBD27490641)
Summary:
The user may wish to run BOLT for printing statistics only
(i.e. to check that the profile is valid). Add an option to run BOLT
without writing any output file, similar to a dry run. This option
is triggered by supplying -o with "/dev/null".
(cherry picked from FBD29568632)
Summary:
During the initial indirect jump analysis, we used to assert that the
discovered jump table type matched the pattern of the corresponding
instruction sequence. E.g., for PIC jump table memory we expected the
PIC jump table instruction sequence. The assertions were too
conservative, as in the case of a mismatch we can mark the indirect jump
as having an unknown control flow. That should be sufficient to either
skip the function processing or rely on relocation information for
possible recovery of the control flow.
(cherry picked from FBD27255816)
Summary:
Fix a bug with instrumentation when trying to instrument
functions that share a jump table with multiple indirect
jumps. Usually, each indirect jump that uses a JT will have its own
copy of it. When this does not happen, we need to duplicate the jump
table safely, so we can split the edges correctly (each copy of the
jump table may have different split edges). For this to happen, we
need to correctly match the sequence of instructions that perform the
indirect jump to identify the base address of the jump table and patch
it to point to the new cloned JT. It was reported to us a case in
which the compiler generated suboptimal code to do an indirect jump
which our matcher failed to identify.
Fixesfacebookincubator/BOLT#126
(cherry picked from FBD27065579)
Summary:
Whenever BOLT encounters a data reference in code, it tries to convert
it into <Object+Offset> form. The primary reason behind this approach is
to support read-only data-reordering optimization. However, with the
current level of the linker and compiler support we don't have enough
information to always correctly restore the original <Object+Offset>.
E.g. with zero-sized symbols we have to speculate that the actual size
of the underlying object extends to the next symbol. Most of the time,
there will be an object pointed by a zero-sized symbol and even
if we are guessing incorrectly, there will be no harm in creating
references of such form.
The problem happens when there's no object corresponding to the original
symbol and the next object is an (unmarked) jump table:
A: # <- zero-sized object
.LJUMP_TABLE:
.long <entry1>
.long <entry2>
....
.LB:
.long 21
.LC:
.long 42
The jump table will be moved and all references past it (up to the next
named object) will be incorrectly updated.
We should not speculate about the size of A in a case like that and
treat all discovered data objects (and thus references) independently.
(cherry picked from FBD27005660)
Summary:
This PR introduces 2 new instrumentation options:
1. instrumentation-no-counters-clear: Discussed at https://github.com/facebookincubator/BOLT/issues/121
2. instrumentation-wait-forks: Since the instrumentation counters are mapped as MAP_SHARED it will be nice to add ability to wait until all forks of the parent process will die using tracking of process group.
The last patch is just emitBinary code refactor.
Vladislav Khmelevsky,
Advanced Software Technology Lab, Huawei
Pull Request resolved: https://github.com/facebookincubator/BOLT/pull/125
GitHub Author: Vladislav Khmelevskyi <Vladislav.Khmelevskyi@huawei.com>
(cherry picked from FBD26919011)
Summary:
TBSS section is a "virtual" section that does not take memory or file
space. Ignore it completely while adjusting section sizes.
(cherry picked from FBD26824484)
Summary:
There is no real link between CU and TU, so relying on fact
that address are the same, and we are updating all of them.
(cherry picked from FBD28112114)
Summary:
This commit is the first step in rebasing all of BOLT
history in the LLVM monorepo. It also solves trivial build issues
by updating BOLT codebase to use current LLVM. There is still work
left in rebasing some BOLT features and in making sure everything
is working as intended.
History has been rewritten to put BOLT in the /bolt folder, as
opposed to /tools/llvm-bolt.
(cherry picked from FBD33289252)
Summary:
1. Add support for __literal16 section in the instrumentation runtime library for MacOS.
2. Fix emitting __counters section.
(cherry picked from FBD25746342)
Summary:
a few minor updates in block reordering:
- some refactoring to improve readability;
- optimized chain splitting strategy to improve quality of layout and performance of the algorithm.
(cherry picked from FBD25126220)
Summary:
When looking at perf.data's available binaries and their
respective mmap'ed segments, match them with the input binary by
looking at both aligned and non-aligned addresses. If we suppose
the alignment is the mmap'ed page size, we may miss some cases and
perf2bolt will refuse to proceed because it failed to match the
input binary with a process recorded in perf.data.
(cherry picked from FBD25732673)
Summary:
Add options for trading processing speed for binary performance.
-lite-threshold-pct=<uint>
Threshold (in percent) for selecting functions to process in lite
mode. Higher threshold means fewer functions to process.
E.g threshold of 90 means only top 10 percent of functions with
profile will be processed.
-lite-threshold-count=<uint>
Similar to '-lite-threshold-pct' but specify threshold using
absolute function call count. I.e. limit processing to functions
executed at least the specified number of times.
-no-scan
Do not scan cold functions for external references (may result in
slower binary).
(cherry picked from FBD24739092)
Summary:
This fixes a bug with shrink wrapping when trying to move
push-pops in a function where we are not allowed to modify the
stack layout for alignment reasons. In this bug, we failed to
propagate alignment requirement upwards in the call graph from
function A to B when: (1) there is a cycle in the call graph and
(2) the distance from A to B is greater than 1 in the call graph
and (3) there is a node in the path from A to B, not including
A or B, that does not access parameters in the stack.
(cherry picked from FBD25315977)
Summary:
This diff is a preparation for dumping the profile generated by BOLT's instrumenation on MachO.
1/ Function "bolt_instr_fini" is placed into the predefined section "__fini"
2/ In the instrumentation pass we create a symbol "bolt_instr_fini" and
replace the last global destructor with it.
This is a temporary solution, in the future we need to register bolt_instr_fini in addition to the existing destructors without dropping the last one.
(cherry picked from FBD25071864)
Summary:
Fix corner case of insertion of updated CFI with unset `PrevBB`.
Handle it in the same way as inserting past hot-cold split point.
(cherry picked from FBD24943911)
Summary:
In BinaryContext::calculateEmittedSize(), after the temporary code
emission, we have to perform a cleanup and mark all symbols used
during the emission as undefined and unregistered (so that we can emit
them again later). The cleanup is happening even for symbols that were
referenced and not defined by emitted code.
If all emitted symbols are local, there is no risk that one thread will
define a symbol while some other thread will undefine it in its cleanup
code. Such behavior is expected as local symbols can only be referenced
within the containing function and each function is processed in one
thread. However, secondary entry points have associated global symbols
and if we emit them, then it is possible for a thread to undefine
a symbol while the other thread had defined it and was in the process of
emitting the fragment with it. In such case, a data race may happen and
the thread that contains the definition of the symbol may define it
twice causing a redefinition error.
To avoid the data race, we skip the emission of secondary entry global
symbols when emitting code used only for the size estimation.
(cherry picked from FBD24986007)
Summary:
A faster and better version of function reordering:
- fixed a bug when some computed probabilities were negative;
- changed an O(n^2) loop to a priority queue to find a candidate of chains to merge
(cherry picked from FBD24571208)
Summary:
Support jump tables belonging to split fragments with entries
pointing back to parent functions.
While skipping such families of functions, make sure to use the
topmost fragment to ignore its fragments.
(cherry picked from FBD24907438)
Summary:
In a jump table identification, register an invalid offset for jump table
entries pointing to function fragments.
These invalid offsets have no effect other than padding the jump
table size, calculated as `max(OffsetEntries, Entries)`.
Correct jump table size is required in strict mode (enabled by default
in aggregation mode by `perf2bolt`) in accounting of all PC-relative
relocations in data.
Functions containing these jump tables with invalid offsets are
marked to be ignored immediately afterwards in
`populateJumpTables`.
(cherry picked from FBD24897464)
Summary:
Introduce new BinaryFunction flag `IsCanonicalCFG`, which gets
unset by SCTC pass. Make DynoStats collection conditional on this
new flag.
SCTC leaves CFG in a state where branch counters of BBs with tail
calls/conditional tail calls are not available (except via annotations,
which get stripped by `lower-annotations`). Without branch
counters, DynoStats are invalid.
(cherry picked from FBD24558050)
Vladislav Khmelevsky