Users should generally observe no difference as long as they don't use
unintended option forms. Behavior changes:
* `-t=d` is removed. Use `-t d` instead.
* `--demangle=false` and `--demangle=0` cannot be used. Omit the option or use `--no-demangle`. Other flag-style options don't have `--no-` forms.
* `--help-list` is removed. This is a `cl::` specific option.
* llvm-readobj now supports grouped short options as well.
* `--color` is removed. This is generally not useful (only apply to errors/warnings) but was inherited from Support.
Some adjustment to the canonical forms
(usually from GNU readelf; currently llvm-readobj has too many redundant aliases):
* --dyn-syms is canonical. --dyn-symbols is a hidden alias
* --file-header is canonical. --file-headers is a hidden alias
* --histogram is canonical. --elf-hash-histogram is a hidden alias
* --relocs is canonical. --relocations is a hidden alias
* --section-groups is canonical. --elf-section-groups is a hidden alias
OptTable avoids global option collision if we decide to support multiplexing for binary utilities.
* Most one-dash long options are still supported. `-dt, -sd, -st, -sr` are dropped due to their conflict with grouped short options.
* `--section-mapping=false` (D57365) is strange but is kept for now.
* Many `cl::opt` variables were unnecessarily external. I added `static` whenever appropriate.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D105532
Part of https://lists.llvm.org/pipermail/llvm-dev/2021-July/151622.html
"Binary utilities: switch command line parsing from llvm::cl to OptTable"
* `--totals=false` and `--totals=0` cannot be used. Omit the option.
* `--help-list` is removed. This is a `cl::` specific option.
OptTable avoids global option collision if we decide to support multiplexing for binary utilities.
Note: because the tool is simple, and its long options are uncommon, I just drop
the one-dash forms except `-arch <value>` (Darwin style).
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D105598
Similar to D104889. The tool is very simple and its long options are uncommon,
so just drop the one-dash form in this patch.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D105605
Part of https://lists.llvm.org/pipermail/llvm-dev/2021-July/151622.html
"Binary utilities: switch command line parsing from llvm::cl to OptTable"
Users should generally observe no difference as long as they only use intended
option forms. Behavior changes:
* `-t=d` is removed. Use `-t d` instead.
* `--demangle=0` cannot be used. Omit the option or use `--no-demangle` instead.
* `--help-list` is removed. This is a `cl::` specific option.
Note:
* `-t` diagnostic gets improved.
* This patch avoids cl::opt collision if we decide to support multiplexing for binary utilities
* One-dash long options are still supported.
* The `-s` collision (`-s segment section` for Mach-O) is unfortunate. `-s` means `--print-armap` in GNU nm.
* This patch removes the last `cl::multi_val` use case from the `llvm/lib/Support/CommandLine.cpp` library
`-M` (`--print-armap`), `-U` (`--defined-only`), and `-W` (`--no-weak`)
are now deprecated. They could conflict with future GNU nm options.
(--print-armap has an existing alias -s, so GNU will unlikely add a new one.
--no-weak (not in GNU nm) is rarely used anyway.)
`--just-symbol-name` is now deprecated in favor of
`--format=just-symbols` and `-j`.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D105330
Some behavior changes:
* `-t=d` is removed. Use `-t d` instead.
* one-dash long options like `-all` are supported. Use `--all` instead.
* `--all=0` or `--all=false` cannot be used. (Note: `--all` is silently ignored anyway)
* `--help-list` is removed. This is a `cl::` specific option.
Nobody is likely leveraging any of the above.
Advantages:
* `-t` diagnostic gets improved.
* in the absence of `HideUnrelatedOptions`, `--help` will not list unrelated options if linking against libLLVM-13git.so or linker GC is not used.
* Decrease the probability of cl::opt collision if we do decide to support multiplexing
Note: because the tool is so simple, used more for forensics instead of a building
tool, and its long options are unlikely used in one-dash form, I just drop the
one-dash form in this patch.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D104889
Summary: The patch adds the StringTable dumping to
llvm-readobj. Currently only XCOFF is supported.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D104613
The new documentation entry gives an example use case from
libomptarget.
Reviewed By: yln, jhenderson, davezarzycki
Differential Revision: https://reviews.llvm.org/D105208
Based on the discussion in PR50922, minor changes have been done to properly
output a valid JSON. Removed "not implemented" keys.
Differential Revision: https://reviews.llvm.org/D105064
llvm-readobj is an internal testing tool for binary formats. Its output and
command line options do not need to be stable. It isn't supposed to be part of a
build process.
llvm-readelf was created as a user-facing utility and its interface intends to
be compatible with GNU readelf (unless there are good reasons not to).
The two tools have mostly compatible options. -s and -t are noticeable
exceptions due to history. I think the cost of keeping the inconsistency
overweighs the little history-compatible benefit and hinders transition from
cl::opt to OptTable, so let's change it.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D105055
The option --no-print-imm-hex was not included in the command guide for
llvm-objdump but appears in the help text. This commit adds it to the
command guide.
Differential Revision: https://reviews.llvm.org/D104717
For now, the source variable locations are printed at about the same
space as the comments for disassembled code, which can make some ranges
for variables disappear if a line contains comments, for example:
┠─ bar = W1
0: add x0, x2, #2, lsl #12 // =8192┃
4: add z31.d, z31.d, #65280 // =0xff00
8: nop ┻
The patch shifts the report a bit to allow printing comments up to
approximately 16 characters without interferences.
Differential Revision: https://reviews.llvm.org/D104700
Fix the command line guide for -g/-s/-S.
In particular, previously it was incorrectly stating that -S is an alias for --strip-all.
Differential revision: https://reviews.llvm.org/D104888
Change --max-timeline-cycles=0 to mean no limit on the number of cycles.
Use this in AMDGPU tests to show all instructions in the timeline view
instead of having it arbitrarily truncated.
Differential Revision: https://reviews.llvm.org/D104846
The original change was pushed in main as commit f7a23ecece.
It was then reverted by commit a04f01bab2 because it caused linker failures
on buildbots that don't build the AMDGPU target.
--
Some instructions are not defined well enough within the target’s scheduling
model for llvm-mca to be able to properly simulate its behaviour. The ideal
solution to this situation is to modify the scheduling model, but that’s not
always a viable strategy. Maybe other parts of the backend depend on that
instruction being modelled the way that it is. Or maybe the instruction is quite
complex and it’s difficult to fully capture its behaviour with tablegen. The
CustomBehaviour class (which I will refer to as CB frequently) is designed to
provide intuitive scaffolding for developers to implement the correct modelling
for these instructions.
More details are available in the original commit log message (f7a23ecece).
Differential Revision: https://reviews.llvm.org/D104149
I believe that after https://reviews.llvm.org/D102355 the behaviour of --print-source-context-lines has changed.
Before: --print-source-context-lines=3 prints 4 lines.
After: --print-source-context-lines=3 prints 3 lines.
Adjust the example in the docs for this change and make the testing a little more robust.
Differential Revision: https://reviews.llvm.org/D104114
Some instructions are not defined well enough within the target’s scheduling
model for llvm-mca to be able to properly simulate its behaviour. The ideal
solution to this situation is to modify the scheduling model, but that’s not
always a viable strategy. Maybe other parts of the backend depend on that
instruction being modelled the way that it is. Or maybe the instruction is quite
complex and it’s difficult to fully capture its behaviour with tablegen. The
CustomBehaviour class (which I will refer to as CB frequently) is designed to
provide intuitive scaffolding for developers to implement the correct modelling
for these instructions.
Implementation details:
llvm-mca does its best to extract relevant register, resource, and memory
information from every MCInst when lowering them to an mca::Instruction. It then
uses this information to detect dependencies and simulate stalls within the
pipeline. For some instructions, the information that gets captured within the
mca::Instruction is not enough for mca to simulate them properly. In these
cases, there are two main possibilities:
1. The instruction has a dependency that isn’t detected by mca.
2. mca is incorrectly enforcing a dependency that shouldn’t exist.
For the rest of this discussion, I will be focusing on (1), but I have put some
thought into (2) and I may revisit it in the future.
So we have an instruction that has dependencies that aren’t picked up by mca.
The basic idea for both pipelines in mca is that when an instruction wants to be
dispatched, we first check for register hazards and then we check for resource
hazards. This is where CB is injected. If no register or resource hazards have
been detected, we make a call to CustomBehaviour::checkCustomHazard() to give
the target specific CB the chance to detect and enforce any custom dependencies.
The return value for checkCustomHazaard() is an unsigned int representing the
(minimum) number of cycles that the instruction needs to stall for. It’s fine to
underestimate this value because when StallCycles gets down to 0, we’ll end up
checking for all the hazards again before the instruction is actually
dispatched. However, it’s important not to overestimate the value and the more
accurate your estimate is, the more efficient mca’s execution can be.
In general, for checkCustomHazard() to be able to detect these custom
dependencies, it needs information about the current instruction and also all of
the instructions that are still executing within the pipeline. The mca pipeline
uses mca::Instruction rather than MCInst and the current information encoded
within each mca::Instruction isn’t sufficient for my use cases. I had to add a
few extra attributes to the mca::Instruction class and have them get set by the
MCInst during instruction building. For example, the current mca::Instruction
doesn’t know its opcode, and it also doesn’t know anything about its immediate
operands (both of which I had to add to the class).
With information about the current instruction, a list of all currently
executing instructions, and some target specific objects (MCSubtargetInfo and
MCInstrInfo which the base CB class has references to), developers should be
able to detect and enforce most custom dependencies within checkCustomHazard. If
you need more information than is present in the mca::Instruction, feel free to
add attributes to that class and have them set during the lowering sequence from
MCInst.
Fortunately, in the in-order pipeline, it’s very convenient for us to pass these
arguments to checkCustomHazard. The hazard checking is taken care of within
InOrderIssueStage::canExecute(). This function takes a const InstRef as a
parameter (representing the instruction that currently wants to be dispatched)
and the InOrderIssueStage class maintains a SmallVector<InstRef, 4> which holds
all of the currently executing instructions. For the out-of-order pipeline, it’s
a bit trickier to get the list of executing instructions and this is why I have
held off on implementing it myself. This is the main topic I will bring up when
I eventually make a post to discuss and ask for feedback.
CB is a base class where targets implement their own derived classes. If a
target specific CB does not exist (or we pass in the -disable-cb flag), the base
class is used. This base class trivially returns 0 from its checkCustomHazard()
implementation (meaning that the current instruction needs to stall for 0 cycles
aka no hazard is detected). For this reason, targets or users who choose not to
use CB shouldn’t see any negative impacts to accuracy or performance (in
comparison to pre-patch llvm-mca).
Differential Revision: https://reviews.llvm.org/D104149
I noticed that I did not update the command guide when introducing the
--rsp-quoting option. This change fixes this.
Differential Revision: https://reviews.llvm.org/D103915
I really needed this, like, factually, yesterday,
when verifying dependency breaking idioms for AMD Zen 3 scheduler model.
Consider the following example:
```
$ ./bin/llvm-exegesis --mode=inverse_throughput --snippets-file=/tmp/snippet.s --num-repetitions=1000000 --repetition-mode=duplicate
Check generated assembly with: /usr/bin/objdump -d /tmp/snippet-4a7e50.o
---
mode: inverse_throughput
key:
instructions:
- 'VPXORYrr YMM0 YMM0 YMM0'
config: ''
register_initial_values: []
cpu_name: znver3
llvm_triple: x86_64-unknown-linux-gnu
num_repetitions: 1000000
measurements:
- { key: inverse_throughput, value: 0.31025, per_snippet_value: 0.31025 }
error: ''
info: ''
assembled_snippet: C5FDEFC0C5FDEFC0C5FDEFC0C5FDEFC0C5FDEFC0C5FDEFC0C5FDEFC0C5FDEFC0C5FDEFC0C5FDEFC0C5FDEFC0C5FDEFC0C5FDEFC0C5FDEFC0C5FDEFC0C5FDEFC0C3
...
```
What does it tell us?
So wait, it can only execute ~3 x86 AVX YMM PXOR zero-idioms per cycle?
That doesn't seem right. That's even less than there are pipes supporting this type of op.
Now, second example:
```
$ ./bin/llvm-exegesis --mode=inverse_throughput --snippets-file=/tmp/snippet.s --num-repetitions=1000000 --repetition-mode=loop
Check generated assembly with: /usr/bin/objdump -d /tmp/snippet-2418b5.o
---
mode: inverse_throughput
key:
instructions:
- 'VPXORYrr YMM0 YMM0 YMM0'
config: ''
register_initial_values: []
cpu_name: znver3
llvm_triple: x86_64-unknown-linux-gnu
num_repetitions: 1000000
measurements:
- { key: inverse_throughput, value: 1.00011, per_snippet_value: 1.00011 }
error: ''
info: ''
assembled_snippet: 49B80800000000000000C5FDEFC0C5FDEFC04983C0FF75F2C3
...
```
Now that's just worse. Due to the looping, the throughput completely plummeted,
and now we can only do a single instruction/cycle!?
That's not great.
And final example:
```
$ ./bin/llvm-exegesis --mode=inverse_throughput --snippets-file=/tmp/snippet.s --num-repetitions=1000000 --repetition-mode=loop --loop-body-size=1000
Check generated assembly with: /usr/bin/objdump -d /tmp/snippet-c402e2.o
---
mode: inverse_throughput
key:
instructions:
- 'VPXORYrr YMM0 YMM0 YMM0'
config: ''
register_initial_values: []
cpu_name: znver3
llvm_triple: x86_64-unknown-linux-gnu
num_repetitions: 1000000
measurements:
- { key: inverse_throughput, value: 0.167087, per_snippet_value: 0.167087 }
error: ''
info: ''
assembled_snippet: 49B80800000000000000C5FDEFC0C5FDEFC04983C0FF75F2C3
...
```
So if we merge the previous two approaches, do duplicate this single-instruction snippet 1000x
(loop-body-size/instruction count in snippet), and run a loop with 1000 iterations
over that duplicated/unrolled snippet, the measured throughput goes through the roof,
up to 5.9 instructions/cycle, which finally tells us that this idiom is zero-cycle!
Reviewed By: courbet
Differential Revision: https://reviews.llvm.org/D102522
In many cases it is helpful to know at what address the resolved function starts.
This patch adds a new StartAddress member to the DILineInfo structure.
Reviewed By: jhenderson, dblaikie
Differential Revision: https://reviews.llvm.org/D102316
This patch adds JSON output style to llvm-symbolizer to better support CLI automation by providing a machine readable output.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D96883
The option --use-symbol-table is now a noop and does not appear in the
help text, however it still appears in the command guide. This change
removes it from the command guide and updates the description of
--output-style .
Differential Revision: https://reviews.llvm.org/D102078
The internal `cl::opt` option --x86-asm-syntax sets the AsmParser and AsmWriter
dialect. The option is used by llc and llvm-mc tests to set the AsmWriter dialect.
This patch adds -M {att,intel} as GNU objdump compatible aliases (PR43413).
Note: the dialect is initialized when the MCAsmInfo is constructed.
`MCInstPrinter::applyTargetSpecificCLOption` is called too late and its MCAsmInfo
reference is const, so changing the `cl::opt` in
`MCInstPrinter::applyTargetSpecificCLOption` is not an option, at least without
large amount of refactoring.
Reviewed By: hoy, jhenderson, thakis
Differential Revision: https://reviews.llvm.org/D101695
The llvm-objdump command guide has the option --cfg which was removed
from the tool by 888320e9fa in 2014. This
change updates the command guide to reflect this.
Differential Revision: https://reviews.llvm.org/D101648
Add a flag to change dsymutil's behavior and force a static variable to
keep its enclosing function. The test shows a situation where that could
be useful. I'm not convinced this behavior makes sense as a default,
which is why it's behind a flag.
rdar://74918374
Differential revision: https://reviews.llvm.org/D101337
This implements an LLVM tool that's flag- and output-compatible
with macOS's `otool` -- except for bugs, but from testing with both
`otool` and `xcrun otool-classic`, llvm-otool matches vanilla
otool's behavior very well already. It's not 100% perfect, but
it's a very solid start.
This uses the same approach as llvm-objcopy: llvm-objdump uses
a different OptTable when it's invoked as llvm-otool. This
is possible thanks to D100433.
Differential Revision: https://reviews.llvm.org/D100583
RVV intrinsics has new overloading rule, please see
82aac7dad4
Changed:
1. Rename `generic` to `overloaded` because the new rule is not using C11 generic.
2. Change HasGeneric to HasNoMaskedOverloaded because all masked operations
support overloading api.
3. Add more overloaded tests due to overloading rule changed.
Differential Revision: https://reviews.llvm.org/D99189
The option `--prefix-strip` is only used when `--prefix` is not empty.
It removes N initial directories from absolute paths before adding the
prefix.
This matches GNU's objdump behavior.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D96679
This is a follow-up for:
D98604 [MCA] Ensure that writes occur in-order
When instructions are aligned by the order of writes, they retire
in-order naturally. There is no need for an RCU, so it is disabled.
Differential Revision: https://reviews.llvm.org/D98628
Lit as it exists today has three hacks that allow users to run tests earlier:
1) An entire test suite can set the `is_early` boolean.
2) A very recently introduced "early_tests" feature.
3) The `--incremental` flag forces failing tests to run first.
All of these approaches have problems.
1) The `is_early` feature was until very recently undocumented. Nevertheless it still lacks testing and is a imprecise way of optimizing test starting times.
2) The `early_tests` feature requires manual updates and doesn't scale.
3) `--incremental` is undocumented, untested, and it requires modifying the *source* file system by "touching" the file. This "touch" based approach is arguably a hack because it confuses editors (because it looks like the test was modified behind the back of the editor) and "touching" the test source file doesn't work if the test suite is read only from the perspective of `lit` (via advanced filesystem/build tricks).
This patch attempts to simplify and address all of the above problems.
This patch formalizes, documents, tests, and defaults lit to recording the execution time of tests and then reordering all tests during the next execution. By reordering the tests, high core count machines run faster, sometimes significantly so.
This patch also always runs failing tests first, which is a positive user experience win for those that didn't know about the hidden `--incremental` flag.
Finally, if users want, they can _optionally_ commit the test timing data (or a subset thereof) back to the repository to accelerate bots and first-time runs of the test suite.
Reviewed By: jhenderson, yln
Differential Revision: https://reviews.llvm.org/D98179
Add printf-style alternate form flag to prefix hex number with 0x when
present. This works on both empty numeric expression (e.g. variable
definition from input) and when matching a numeric expression. The
syntax is as follows:
[[#%#<precision specifier><format specifier>, ...]
where <precision specifier> and <format specifier> are optional and ...
can be a variable definition or not with an empty expression or not.
This feature was requested in https://reviews.llvm.org/D81144#2075532
for llvm/test/MC/ELF/gen-dwarf64.s
Reviewed By: jdenny
Differential Revision: https://reviews.llvm.org/D97845
Demonstrate how to generate vadd/vfadd intrinsic functions
1. add -gen-riscv-vector-builtins for clang builtins.
2. add -gen-riscv-vector-builtin-codegen for clang codegen.
3. add -gen-riscv-vector-header for riscv_vector.h. It also generates
ifdef directives with extension checking, base on D94403.
4. add -gen-riscv-vector-generic-header for riscv_vector_generic.h.
Generate overloading version Header for generic api.
https://github.com/riscv/rvv-intrinsic-doc/blob/master/rvv-intrinsic-rfc.md#c11-generic-interface
5. update tblgen doc for riscv related options.
riscv_vector.td also defines some unused type transformers for vadd,
because I think it could demonstrate how tranfer type work and we need
them for the whole intrinsic functions implementation in the future.
Authored-by: Roger Ferrer Ibanez <rofirrim@gmail.com>
Co-Authored-by: Zakk Chen <zakk.chen@sifive.com>
Reviewed By: jrtc27, craig.topper, HsiangKai, Jim, Paul-C-Anagnostopoulos
Differential Revision: https://reviews.llvm.org/D95016
This diff introduces --keep-undefined in llvm-objcopy/llvm-strip for Mach-O
which makes the tools preserve undefined symbols.
Test plan: make check-all
Differential revision: https://reviews.llvm.org/D97040
This patch adds a pipeline to support in-order CPUs such as ARM
Cortex-A55.
In-order pipeline implements a simplified version of Dispatch,
Scheduler and Execute stages as a single stage. Entry and Retire
stages are common for both in-order and out-of-order pipelines.
Differential Revision: https://reviews.llvm.org/D94928
The help text and documentation for the --discard-all option failed to
mention that the option also causes the removal of debug sections. This
change fixes both for both llvm-objcopy and llvm-strip.
Reviewed by: MaskRay
Differential Revision: https://reviews.llvm.org/D97662
For some build configurations, `check-all` calls lit multiple times to
run multiple lit test suites. Most recently, I've found this to be
true when configuring openmp as part of `LLVM_ENABLE_RUNTIMES`, but
this is not the first time.
If one test suite fails, none of the remaining test suites run, so you
cannot determine if your patch has broken them. It can then be
frustrating to try to determine which `check-` targets will run the
remaining tests without getting stuck on the failing tests.
When such cases arise, it is probably best to adjust the cmake
configuration for `check-all` to run all test suites as part of one
lit invocation. Because that fix will likely not be implemented and
land immediately, this patch introduces `--ignore-fail` to serve as a
workaround for developers trying to see test results until it does
land:
```
$ LIT_OPTS=--ignore-fail ninja check-all
```
One problem with `--ignore-fail` is that it makes it challenging to
detect test failures in a script, perhaps in CI. This problem should
serve as motivation to actually fix the cmake configuration instead of
continuing to use `--ignore-fail` indefinitely.
Reviewed By: jhenderson, thopre
Differential Revision: https://reviews.llvm.org/D96371
In semi-automated environments, XFAILing or filtering out known regressions without actually committing changes or temporarily modifying the test suite can be quite useful.
Reviewed By: yln
Differential Revision: https://reviews.llvm.org/D96662
With enough cores, the slowest tests can significantly change the total testing time if they happen to run late. With this change, a test suite can improve performance (for high-end systems) by listing just a few of the slowest tests up front.
Reviewed By: jdenny, jhenderson
Differential Revision: https://reviews.llvm.org/D96594
Some test systems do not use lit for test discovery but only for its
substitution and test selection because they use another way of managing
test collections, e.g. CTest. This forces those tests to be invoked with
lit --no-indirectly-run-check. When a mix of lit version is in use, it
requires to detect the availability of that option.
This commit provides a new config option standalone_tests to signal a
directory made of tests meant to run as standalone. When this option is
set, lit skips test discovery and the indirectly run check. It also adds
the missing documentation for --no-indirectly-run-check.
Reviewed By: jdenny
Differential Revision: https://reviews.llvm.org/D94766
1. Emit warnings for files without symbols.
2. Add -no_warning_for_no_symbols.
Test plan: make check-all
Differential revision: https://reviews.llvm.org/D95843
The few options are niche. They solved a problem which was traditionally solved
with more shell commands (`llvm-readelf -n` fetches the Build ID. Then
`ln` is used to hard link the file to a directory derived from the Build ID.)
Due to limitation, they are no longer used by Fuchsia and they don't appear to
be used elsewhere (checked with Google Search and Debian Code Search). So delete
them without a transition period.
Announcement: https://lists.llvm.org/pipermail/llvm-dev/2021-February/148446.html
Differential Revision: https://reviews.llvm.org/D96310
This puts it in alphabetical order, matching the rest of the list.
Reviewed by: MaskRay, saugustine
Differential Revision: https://reviews.llvm.org/D94481
This is an enhancement to LLVM Source-Based Code Coverage in clang to track how
many times individual branch-generating conditions are taken (evaluate to TRUE)
and not taken (evaluate to FALSE). Individual conditions may comprise larger
boolean expressions using boolean logical operators. This functionality is
very similar to what is supported by GCOV except that it is very closely
anchored to the ASTs.
Differential Revision: https://reviews.llvm.org/D84467
Introduce CHECK modifiers that change the behavior of the CHECK
directive. Also add a LITERAL modifier for cases where matching could
end requiring escaping strings interpreted as regex where only
literal/fixed string matching is desired (making the CHECK's more
difficult to write/fragile and difficult to interpret).
This stack of changes introduces `llvm-profgen` utility which generates a profile data file from given perf script data files for sample-based PGO. It’s part of(not only) the CSSPGO work. Specifically to support context-sensitive with/without pseudo probe profile, it implements a series of functionalities including perf trace parsing, instruction symbolization, LBR stack/call frame stack unwinding, pseudo probe decoding, etc. Also high throughput is achieved by multiple levels of sample aggregation and compatible format with one stop is generated at the end. Please refer to: https://groups.google.com/g/llvm-dev/c/1p1rdYbL93s for the CSSPGO RFC.
This change supports context-sensitive profile data generation into llvm-profgen. With simultaneous sampling for LBR and call stack, we can identify leaf of LBR sample with calling context from stack sample . During the process of deriving fall through path from LBR entries, we unwind LBR by replaying all the calls and returns (including implicit calls/returns due to inlining) backwards on top of the sampled call stack. Then the state of call stack as we unwind through LBR always represents the calling context of current fall through path.
we have two types of virtual unwinding 1) LBR unwinding and 2) linear range unwinding.
Specifically, for each LBR entry which can be classified into call, return, regular branch, LBR unwinding will replay the operation by pushing, popping or switching leaf frame towards the call stack and since the initial call stack is most recently sampled, the replay should be in anti-execution order, i.e. for the regular case, pop the call stack when LBR is call, push frame on call stack when LBR is return. After each LBR processed, it also needs to align with the next LBR by going through instructions from previous LBR's target to current LBR's source, which we named linear unwinding. As instruction from linear range can come from different function by inlining, linear unwinding will do the range splitting and record counters through the range with same inline context.
With each fall through path from LBR unwinding, we aggregate each sample into counters by the calling context and eventually generate full context sensitive profile (without relying on inlining) to driver compiler's PGO/FDO.
A breakdown of noteworthy changes:
- Added `HybridSample` class as the abstraction perf sample including LBR stack and call stack
* Extended `PerfReader` to implement auto-detect whether input perf script output contains CS profile, then do the parsing. Multiple `HybridSample` are extracted
* Speed up by aggregating `HybridSample` into `AggregatedSamples`
* Added VirtualUnwinder that consumes aggregated `HybridSample` and implements unwinding of calls, returns, and linear path that contains implicit call/return from inlining. Ranges and branches counters are aggregated by the calling context. Here calling context is string type, each context is a pair of function name and callsite location info, the whole context is like `main:1 @ foo:2 @ bar`.
* Added PorfileGenerater that accumulates counters by ranges unfolding or branch target mapping, then generates context-sensitive function profile including function body, inferring callee's head sample, callsite target samples, eventually records into ProfileMap.
* Leveraged LLVM build-in(`SampleProfWriter`) writer to support different serialization format with no stop
- `getCanonicalFnName` for callee name and name from ELF section
- Added regression test for both unwinding and profile generation
Test Plan:
ninja & ninja check-llvm
Reviewed By: hoy, wenlei, wmi
Differential Revision: https://reviews.llvm.org/D89723
This does the same as `--mcpu=help` but was only
documented in the user guide.
* Added a test for both options.
* Corrected the single dash in `-mcpu=help` text.
Reviewed By: jhenderson
Differential Revision: https://reviews.llvm.org/D92305
llvm-symbolizer used to use the DIA SDK for symbolization on
Windows; this patch switches to using native symbolization, which was
implemented recently.
Users can still make the symbolizer use DIA by adding the `-dia` flag
in the LLVM_SYMBOLIZER_OPTS environment variable.
Differential Revision: https://reviews.llvm.org/D91814
This stack of changes introduces `llvm-profgen` utility which generates a profile data file from given perf script data files for sample-based PGO. It’s part of(not only) the CSSPGO work. Specifically to support context-sensitive with/without pseudo probe profile, it implements a series of functionalities including perf trace parsing, instruction symbolization, LBR stack/call frame stack unwinding, pseudo probe decoding, etc. Also high throughput is achieved by multiple levels of sample aggregation and compatible format with one stop is generated at the end. Please refer to: https://groups.google.com/g/llvm-dev/c/1p1rdYbL93s for the CSSPGO RFC.
This change enables disassembling the text sections to build various address maps that are potentially used by the virtual unwinder. A switch `--show-disassembly` is being added to print the disassembly code.
Like the llvm-objdump tool, this change leverages existing LLVM components to parse and disassemble ELF binary files. So far X86 is supported.
Test Plan:
ninja check-llvm
Reviewed By: wmi, wenlei
Differential Revision: https://reviews.llvm.org/D89712
This stack of changes introduces `llvm-profgen` utility which generates a profile data file from given perf script data files for sample-based PGO. It’s part of(not only) the CSSPGO work. Specifically to support context-sensitive with/without pseudo probe profile, it implements a series of functionalities including perf trace parsing, instruction symbolization, LBR stack/call frame stack unwinding, pseudo probe decoding, etc. Also high throughput is achieved by multiple levels of sample aggregation and compatible format with one stop is generated at the end. Please refer to: https://groups.google.com/g/llvm-dev/c/1p1rdYbL93s for the CSSPGO RFC.
As a starter, this change sets up an entry point by introducing PerfReader to load profiled binaries and perf traces(including perf events and perf samples). For the event, here it parses the mmap2 events from perf script to build the loader snaps, which is used to retrieve the image load address in the subsequent perf tracing parsing.
As described in llvm-profgen.rst, the tool being built aims to support multiple input perf data (preprocessed by perf script) as well as multiple input binary images. It should also support dynamic reload/unload shared objects by leveraging the loader snaps being built by this change
Reviewed By: wenlei, wmi
Differential Revision: https://reviews.llvm.org/D89707
Describe in the BackEnd Developer's Guide. Instrument a few backends.
Remove an old unused timing facility. Add a null backend for timing
the parser.
Differential Revision: https://reviews.llvm.org/D91388
No longer rely on an external tool to build the llvm component layout.
Instead, leverage the existing `add_llvm_componentlibrary` cmake function and
introduce `add_llvm_component_group` to accurately describe component behavior.
These function store extra properties in the created targets. These properties
are processed once all components are defined to resolve library dependencies
and produce the header expected by llvm-config.
Differential Revision: https://reviews.llvm.org/D90848
Add a few cross-references among TableGen documents.
Differential Revision: https://reviews.llvm.org/D90186
Add cross-references between TableGen documents.
--section-details/-t is a GNU readelf option that produce
an output that is an alternative to --sections.
Differential revision: https://reviews.llvm.org/D89304
The prefix given to --prefix will be added to GNU absolute paths when
used with --source option (source interleaved with the disassembly).
This matches GNU's objdump behavior.
GNU and C++17 rules for absolute paths are different.
Differential Revision: https://reviews.llvm.org/D85024
Fixes PR46368.
Differential Revision: https://reviews.llvm.org/D85024
Add printf-style precision specifier to pad numbers to a given number of
digits when matching them if the value is smaller than the given
precision. This works on both empty numeric expression (e.g. variable
definition from input) and when matching a numeric expression. The
syntax is as follows:
[[#%.<precision><format specifier>, ...]
where <format specifier> is optional and ... can be a variable
definition or not with an empty expression or not. In the absence of a
precision specifier, a variable definition will accept leading zeros.
Reviewed By: jhenderson, grimar
Differential Revision: https://reviews.llvm.org/D81667
When diffing disassembly dump of two binaries, I see lots of noises from mismatched jump target addresses and global data references, which unnecessarily causes diffs on every function, making it impractical. I'm trying to symbolize the raw binary addresses to minimize the diff noise.
In this change, a local branch target is modeled as a label and the branch target operand will simply be printed as a label. Local labels are collected by a separate pre-decoding pass beforehand. A global data memory operand will be printed as a global symbol instead of the raw data address. Unfortunately, due to the way the disassembler is set up and to be less intrusive, a global symbol is always printed as the last operand of a memory access instruction. This is less than ideal but is probably acceptable from checking code quality point of view since on most targets an instruction can have at most one memory operand.
So far only the X86 disassemblers are supported.
Test Plan:
llvm-objdump -d --x86-asm-syntax=intel --no-show-raw-insn --no-leading-addr :
```
Disassembly of section .text:
<_start>:
push rax
mov dword ptr [rsp + 4], 0
mov dword ptr [rsp], 0
mov eax, dword ptr [rsp]
cmp eax, dword ptr [rip + 4112] # 202182 <g>
jge 0x20117e <_start+0x25>
call 0x201158 <foo>
inc dword ptr [rsp]
jmp 0x201169 <_start+0x10>
xor eax, eax
pop rcx
ret
```
llvm-objdump -d **--symbolize-operands** --x86-asm-syntax=intel --no-show-raw-insn --no-leading-addr :
```
Disassembly of section .text:
<_start>:
push rax
mov dword ptr [rsp + 4], 0
mov dword ptr [rsp], 0
<L1>:
mov eax, dword ptr [rsp]
cmp eax, dword ptr <g>
jge <L0>
call <foo>
inc dword ptr [rsp]
jmp <L1>
<L0>:
xor eax, eax
pop rcx
ret
```
Note that the jump instructions like `jge 0x20117e <_start+0x25>` without this work is printed as a real target address and an offset from the leading symbol. With a change in the optimizer that adds/deletes an instruction, the address and offset may shift for targets placed after the instruction. This will be a problem when diffing the disassembly from two optimizers where there are unnecessary false positives due to such branch target address changes. With `--symbolize-operand`, a label is printed for a branch target instead to reduce the false positives. Similarly, the disassemble of PC-relative global variable references is also prone to instruction insertion/deletion.
Reviewed By: jhenderson, MaskRay
Differential Revision: https://reviews.llvm.org/D84191
Add support for passing in libraries via `-l` and `-L` options to
`llvm-libtool-darwin`.
Reviewed by jhenderson, smeenai
Differential Revision: https://reviews.llvm.org/D85540
Add support for -arch_only option for llvm-libtool-darwin. This diff
also adds support for accepting universal files as input and flattening
them to create the required static library. Supports input universal
files contaning both Mach-O object files or archives.
Differences from cctools' libtool:
- `-arch_only` can be specified multiple times
- archives containing universal files are considered invalid (libtool
allows such archives)
Reviewed by jhenderson, smeenai
Differential Revision: https://reviews.llvm.org/D84770
Add documentation for the remaining options of
`llvm-install-name-tool`.
Reviewed by jhenderson, smeenai
Differential Revision: https://reviews.llvm.org/D85655
The switch from llvm::cl to OptTable (D83530) dropped --version, which
is needed by some users.
This patch also adds a -v alias, which is available in GNU addr2line.
The version dumping is similar to llvm-objcopy --version (exotic):
```
llvm-symbolizer
LLVM (http://llvm.org/):
LLVM version 12.0.0git
Optimized build with assertions.
Default target: x86_64-unknown-linux-gnu
Host CPU: skylake-avx512
```
Reviewed By: dyung, jhenderson
Differential Revision: https://reviews.llvm.org/D85624
Add support for `-D` and `-U` options for llvm-libtool-darwin. `-D`
allows for using zero for timestamps and UIDs/GIDs. `-U` allows for
using actual timestamps and UIDs/GIDs.
Reviewed by jhenderson, smeenai
Differential Revision: https://reviews.llvm.org/D84209
Add support for `-filelist` option for llvm-libtool-darwin. `-filelist`
option allows for passing in a file containing a list of filenames.
Reviewed by jhenderson, smeenai
Differential Revision: https://reviews.llvm.org/D84206
Vedant Kumar