148 Commits

Author SHA1 Message Date
Chinmay Deshpande
848bef5d85
[llvm-mca] Add command line option -call-latency (#92958)
Currently we assume a constant latency of 100 cycles for call
instructions. This commit allows the user to specify a custom value for
the same as a command line argument. Default latency is set to 100.
2024-05-22 13:51:55 -07:00
Peter Waller
1de0535e84
[llvm-mca] Abort on parse error without -skip-unsupported-instructions (#90474)
[llvm-mca] Abort on parse error without -skip-unsupported-instructions

Prior to this patch, llvm-mca would continue executing after parse
errors. These errors can lead to some confusion since some analysis
results are printed on the standard output, and they're printed after
the errors, which could otherwise be easy to miss.

However it is still useful to be able to continue analysis after errors;
so extend the recently added -skip-unsupported-instructions to support
this.

Two tests which have parse errors for some of the 'RUN' branches are
updated to use -skip-unsupported-instructions so they can remain as-is.

Add a description of -skip-unsupported-instructions to the llvm-mca
command guide, and add it to the llvm-mca --help output:

```
  --skip-unsupported-instructions=<value> - Force analysis to continue in the presence of unsupported instructions
    =none                                 -   Exit with an error when an instruction is unsupported for any reason (default)
    =lack-sched                           -   Skip instructions on input which lack scheduling information
    =parse-failure                        -   Skip lines on the input which fail to parse for any reason
    =any                                  -   Skip instructions or lines on input which are unsupported for any reason
```

Tests within this patch are intended to cover each of the cases.

Reason        | Flag | Comment
--------------|------|-------
none          | none | Usual case, existing test suite
lack-sched    | none | Advises user to use -skip-unsupported-instructions=lack-sched, tested in llvm/test/tools/llvm-mca/X86/BtVer2/unsupported-instruction.s
parse-failure | none | Advises user to use -skip-unsupported-instructions=parse-failure, tested in llvm/test/tools/llvm-mca/bad-input.s
any           | none | (N/A, covered above)
lack-sched    | any  | Continues, prints warnings, tested in llvm/test/tools/llvm-mca/X86/BtVer2/unsupported-instruction.s
parse-failure | any  | Continues, prints errors, tested in llvm/test/tools/llvm-mca/bad-input.s
lack-sched    | parse-failure | Advises user to use -skip-unsupported-instructions=lack-sched, tested in llvm/test/tools/llvm-mca/X86/BtVer2/unsupported-instruction.s
parse-failure | lack-sched    | Advises user to use -skip-unsupported-instructions=parse-failure, tested in llvm/test/tools/llvm-mca/bad-input.s
none          | * | This would be any test case with skip-unsupported-instructions, coverage added in llvm/test/tools/llvm-mca/X86/BtVer2/simple-test.s
any           | * | (Logically covered by the other cases)
2024-05-07 09:13:44 +01:00
Peter Waller
5f79f7506a
[llvm-mca] Add -skip-unsupported-instructions option (#89733)
Prior to this patch, if llvm-mca encountered an instruction which parses
but has no scheduler info, the instruction is always reported as
unsupported, and llvm-mca halts with an error.

However, it would still be useful to allow MCA to continue even in the
case of instructions lacking scheduling information. Obviously if
scheduling information is lacking, it's not possible to give an accurate
analysis for those instructions, and therefore a warning is emitted.

A user could previously have worked around such unsupported instructions
manually by deleting such instructions from the input, but this provides
them a way of doing this for bulk inputs where they may not have a list
of such unsupported instructions to drop up front.

Note that this behaviour of instructions with no scheduling information
under -skip-unsupported-instructions is analagous to current
instructions which fail to parse: those are currently dropped from the
input with a message printed, after which the analysis continues.

~Testing the feature is a little awkward currently, it relies on an
instruction
which is currently marked as unsupported, which may not remain so;
should the
situation change it would be necessary to find an alternative
unsupported
instruction or drop the test.~

A test is added to check that analysis still reports an error if all
instructions are removed from the input, to mirror the current behaviour
of giving an error if no instructions are supplied.
2024-04-29 08:39:15 +01:00
Michael Maitland
c1fe1474d2 [llvm-mca] Print InstructionInfoView using Instrument information.
Previous reports calculated the overall report using Instrument
information but did not print out per-instruction data using
Instrument information. This patch fixes that.

Differential Revision: https://reviews.llvm.org/D150459
2023-05-22 16:41:19 -07:00
Michael Maitland
56674e8e4a [llvm-mca][RISCV] Fix llvm-mca RISCVInstrument memory leak
There was a memory leak that presented itself once the llvm-mca
tests were committed. This leak was not checked for by the pre-commit
tests. This change changes the shared_ptr to a unique_ptr to avoid
this problem.

We will know that this fix works once committed since I don't know
whether it is possible to force a lit test to use LSan. I spent the
day trying to build llvm with LSan enabled without much luck. If
anyone knows how to build llvm with LSan for the lit-tests, I am
happy to give it another try locally.

Differential Revision: https://reviews.llvm.org/D150816
2023-05-22 10:36:41 -07:00
Michael Maitland
1c2b8129e9 [llvm-mca] Fix duplicate symbols error
Parsing instruments and analysis regions causes us to see the same
labels two times since we parse the same file twice under the same
context.

This change creates a seperate context for instrument parsing
and another for analysis region parsing. I will post a follow up
commit once I get some free cycles to parse analysis regions and
instruments in one parsing pass under a single context.

Differential Revision: https://reviews.llvm.org/D149781
2023-05-03 18:01:46 -07:00
Archibald Elliott
d768bf994f [NFC][TargetParser] Replace uses of llvm/Support/Host.h
The forwarding header is left in place because of its use in
`polly/lib/External/isl/interface/extract_interface.cc`, but I have
added a GCC warning about the fact it is deprecated, because it is used
in `isl` from where it is included by Polly.
2023-02-10 09:59:46 +00:00
Archibald Elliott
142aa1bdd1 [Support] Move Target/CPU Printing out of CommandLine
This change is rather more invasive than intended. The main intention
here is to make CommandLine.cpp not rely on llvm/Support/Host.h. Right
now, this reliance is only in 3 superficial places:
- Choosing how to expand response files (in two places)
- Printing the default triple and current CPU in `--version` output.

The built in version system has a method for adding "extra version
printers", commonly used by several tools (such as llc) to report the
registered targets in the built version of LLVM. It was reasonably easy
to move the logic for printing the default triple and current CPU into
a similar function, and register it with any relevant binaries.

The incompatible change here is that now, even if
LLVM_VERSION_PRINTER_SHOW_HOST_TARGET_INFO is defined, most binaries
will no longer print out the default target triple and cpu when provided
with `--version`, for instance llvm-as and llvm-dis. This breakage is
intended, but the changes in this patch keep printing the default target
and detected in `llc` and `opt` as these were remarked as important
binaries in the LLVM install.

The change to expanding response files may also be controversial, but I
believe that these macros should correspond exactly to the host triple
introspection used before.

Differential Revision: https://reviews.llvm.org/D137837
2022-12-20 09:56:14 +00:00
Michael Maitland
98e342dca2 [RISCV][llvm-mca] Use LMUL Instruments to provide more accurate reports on RISCV
On x86 and AArch, SIMD instructions encode all of the scheduling information in the instruction
itself. For example, VADD.I16 q0, q1, q2 is a neon instruction that operates on 16-bit integer
elements stored in 128-bit Q registers, which leads to eight 16-bit lanes in parallel. This kind
of information impacts how the instruction takes to execute and what dependencies this may cause.

On RISCV however, the data that impacts scheduling is encoded in CSR registers such as vtype or
vl, in addition with the instruction itself. But MCA does not track or use the data in these
registers. This patch fixes this problem by introducing Instruments into MCA.

* Replace `CodeRegions` with `AnalysisRegions`
* Add `Instrument` and `InstrumentManager`
* Add `InstrumentRegions`
* Add RISCV Instrument and `InstrumentManager`
* Parse `Instruments` in driver
* Use instruments to override schedule class
* RISCV use lmul instrument to override schedule class
* Fix unit tests to pass empty instruments
* Add -ignore-im clopt to disable this change

A prior version of this patch was commited in 5e82ee537321. 2323a4ee610f reverted
that change because the unit test files caused build errors. The change with fixes
were committed in b88b8307bf9e but reverted once again e8e92c8313a0 due to more
build errors.

This commit adds the prior changes and fixes the build error.

Differential Revision: https://reviews.llvm.org/D137440
2022-11-18 09:55:15 -08:00
Michael Maitland
e8e92c8313 Revert "[RISCV][llvm-mca] Use LMUL Instruments to provide more accurate reports on RISCV"
This reverts commit b88b8307bf9e24f53e7ef3052abf2c506ff55fd2.
2022-11-15 18:01:46 -08:00
Michael Maitland
b88b8307bf [RISCV][llvm-mca] Use LMUL Instruments to provide more accurate reports on RISCV
On x86 and AArch, SIMD instructions encode all of the scheduling information in the instruction
itself. For example, VADD.I16 q0, q1, q2 is a neon instruction that operates on 16-bit integer
elements stored in 128-bit Q registers, which leads to eight 16-bit lanes in parallel. This kind
of information impacts how the instruction takes to execute and what dependencies this may cause.

On RISCV however, the data that impacts scheduling is encoded in CSR registers such as vtype or
vl, in addition with the instruction itself. But MCA does not track or use the data in these
registers. This patch fixes this problem by introducing Instruments into MCA.

* Replace `CodeRegions` with `AnalysisRegions`
* Add `Instrument` and `InstrumentManager`
* Add `InstrumentRegions`
* Add RISCV Instrument and `InstrumentManager`
* Parse `Instruments` in driver
* Use instruments to override schedule class
* RISCV use lmul instrument to override schedule class
* Fix unit tests to pass empty instruments
* Add -ignore-im clopt to disable this change

A prior version of this patch was commited in. It was reverted in
5e82ee5373211db8522181054800ccd49461d9d8. 2323a4ee610f5e1db74d362af4c6fb8c704be8f6 reverted
that change because the unit test files caused build errors. This commit adds the original changes
and the fixed test files.

Differential Revision: https://reviews.llvm.org/D137440
2022-11-15 17:42:23 -08:00
Michael Maitland
2323a4ee61 Revert "[RISCV][llvm-mca] Use LMUL Instruments to provide more accurate reports on RISCV"
This reverts commit 5e82ee5373211db8522181054800ccd49461d9d8.
2022-11-15 08:04:11 -08:00
Michael Maitland
5e82ee5373 [RISCV][llvm-mca] Use LMUL Instruments to provide more accurate reports on RISCV
On x86 and AArch, SIMD instructions encode all of the scheduling information in the instruction
itself. For example, VADD.I16 q0, q1, q2 is a neon instruction that operates on 16-bit integer
elements stored in 128-bit Q registers, which leads to eight 16-bit lanes in parallel. This kind
of information impacts how the instruction takes to execute and what dependencies this may cause.

On RISCV however, the data that impacts scheduling is encoded in CSR registers such as vtype or
vl, in addition with the instruction itself. But MCA does not track or use the data in these
registers. This patch fixes this problem by introducing Instruments into MCA.

* Replace `CodeRegions` with `AnalysisRegions`
* Add `Instrument` and `InstrumentManager`
* Add `InstrumentRegions`
* Add RISCV Instrument and `InstrumentManager`
* Parse `Instruments` in driver
* Use instruments to override schedule class
* RISCV use lmul instrument to override schedule class
* Fix unit tests to pass empty instruments
* Add -ignore-im clopt to disable this change

Differential Revision: https://reviews.llvm.org/D137440
2022-11-15 07:54:06 -08:00
Cullen Rhodes
767b26a4e2 [MCA] Support multiple comma-separated -mattr features
Reviewed By: myhsu

Differential Revision: https://reviews.llvm.org/D129479
2022-07-12 08:20:11 +00:00
Min-Yih Hsu
97579dcc6d [MCA] Introducing incremental SourceMgr and resumable pipeline
The new resumable mca::Pipeline capability introduced in this patch
allows users to save the current state of pipeline and resume from the
very checkpoint.
It is better (but not require) to use with the new IncrementalSourceMgr,
where users can add mca::Instruction incrementally rather than having a
fixed number of instructions ahead-of-time.

Note that we're using unit tests to test these new features. Because
integrating them into the `llvm-mca` tool will make too many churns.

Differential Revision: https://reviews.llvm.org/D127083
2022-06-24 15:39:51 -07:00
Patrick Holland
55cedf9cc5 [MCA] Moved six instruction flags from InstrDesc to InstructionBase.
Differential Revision: https://reviews.llvm.org/D121508
2022-03-13 21:21:05 -07:00
Shao-Ce SUN
2aed07e96c [NFC][MC] remove unused argument MCRegisterInfo in MCCodeEmitter
Reviewed By: skan

Differential Revision: https://reviews.llvm.org/D119846
2022-02-16 13:10:09 +08:00
Shao-Ce SUN
9cc49c1951 Revert "[NFC][MC] remove unused argument MCRegisterInfo in MCCodeEmitter"
This reverts commit fe25c06cc5bdc2ef9427309f8ec1434aad69dc7a.
2022-02-16 11:57:49 +08:00
Shao-Ce SUN
fe25c06cc5 [NFC][MC] remove unused argument MCRegisterInfo in MCCodeEmitter
For ten years, it seems that `MCRegisterInfo` is not used by any target.

Reviewed By: skan

Differential Revision: https://reviews.llvm.org/D119846
2022-02-16 11:47:17 +08:00
Patrick Holland
85e6e748d4 [MCA] Switching from conservatively guessing which instructions are
memory-barrier instructions to providing targets and developers a convenient
way to explicitly declare which instructions are memory-barriers.

Differential Revision: https://reviews.llvm.org/D116779
2022-01-11 13:50:14 -08:00
Andrew Savonichev
420300c0d8 [MCA] Remove the warning about experimental support for in-order CPU
There are not a lot of bug reports for this feature, so let's mark it
stable.

Differential Revision: https://reviews.llvm.org/D114701
2021-12-07 15:27:51 +03:00
Reid Kleckner
89b57061f7 Move TargetRegistry.(h|cpp) from Support to MC
This moves the registry higher in the LLVM library dependency stack.
Every client of the target registry needs to link against MC anyway to
actually use the target, so we might as well move this out of Support.

This allows us to ensure that Support doesn't have includes from MC/*.

Differential Revision: https://reviews.llvm.org/D111454
2021-10-08 14:51:48 -07:00
Patrick Holland
fe01014faa [MCA] Moved View.h and View.cpp from /tools/llvm-mca/ to /lib/MCA/.
Moved View.h and View.cpp from /tools/llvm-mca/Views/ to /lib/MCA/ and
/include/llvm/MCA/. This is so that targets can define their own Views within
the /lib/Target/ directory (so that the View can use backend functionality).
To enable these Views within mca, targets will need to add them to the vector of
Views returned by their target's CustomBehaviour::getViews() methods.

Differential Revision: https://reviews.llvm.org/D108520
2021-08-25 12:12:47 -07:00
Patrick Holland
dbed061bf1 [MCA] Moving the target specific CustomBehaviour impl. from /tools/llvm-mca/ to /lib/Target/.
Differential Revision: https://reviews.llvm.org/D106775
2021-07-28 11:23:18 -07:00
Marcos Horro
77f2f0f9b7 [llvm-mca][JSON] Store extra information about driver flags used for the simulation
Added information stored in PipelineOptions and the MCSubtargetInfo.

Bug: https://bugs.llvm.org/show_bug.cgi?id=51041

Reviewed By: andreadb

Differential Revision: https://reviews.llvm.org/D106077
2021-07-16 09:18:40 +02:00
Marcos Horro
14f77576c9 [llvm-mca] [NFC] Formatting code
Applied clang-format to all files. Discarded BottleneckAnalysis.h
80-column width violation since it contains an example of report.
Caught some typos and minor style details.

Reviewed By: andreadb

Differential Revision: https://reviews.llvm.org/D105900
2021-07-13 19:13:59 +02:00
Andrea Di Biagio
10cb036223 [llvm-mca] Refactor the logic that prints JSON files.
Moved most of the printing logic into the PipelinePrinter.

This patch also fixes the JSON output when flag -instruction-tables is
specified.
2021-07-09 22:56:39 +01:00
Fangrui Song
a2860b8b04 [llvm-mca] Fix -Wunused-private-field after D105618 2021-07-09 10:30:16 -07:00
Marcos Horro
b11d31eb73 [llvm-mca] Fix JSON format for multiple regions
Instead of printing each region individually when using JSON format,
this patch creates a JSON object which is updated with the values of
each region, printing them at the end. New test is added for JSON output
with multiple regions.

Bug: https://bugs.llvm.org/show_bug.cgi?id=51008

Reviewed By: andreadb

Differential Revision: https://reviews.llvm.org/D105618
2021-07-09 18:04:16 +02:00
Jay Foad
beebe5a056 [MCA] Allow unlimited cycles in the timeline view
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
2021-06-24 12:54:57 +01:00
Patrick Holland
ef16c8eaa5 Reapply "[MCA] Adding the CustomBehaviour class to llvm-mca".
The original change was pushed in main as commit f7a23ecece52.
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 (f7a23ecece52).

Differential Revision: https://reviews.llvm.org/D104149
2021-06-16 16:54:48 +01:00
Andrea Di Biagio
a04f01bab2 Revert "[MCA] Adding the CustomBehaviour class to llvm-mca"
This reverts commit f7a23ecece524564a0c3e09787142cc6061027bb.

It appears to breaks buildbots that don't build the AMDGPU backend.
2021-06-15 21:41:36 +01:00
Patrick Holland
f7a23ecece [MCA] Adding the CustomBehaviour class to llvm-mca
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
2021-06-15 21:30:48 +01:00
Philipp Krones
c2f819af73 [MC] Refactor MCObjectFileInfo initialization and allow targets to create MCObjectFileInfo
This makes it possible for targets to define their own MCObjectFileInfo.
This MCObjectFileInfo is then used to determine things like section alignment.

This is a follow up to D101462 and prepares for the RISCV backend defining the
text section alignment depending on the enabled extensions.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D101921
2021-05-23 14:15:23 -07:00
Patrick Holland
e5d59db469 [MCA] llvm-mca MCTargetStreamer segfault fix
In order to create the code regions for llvm-mca to analyze, llvm-mca creates an
AsmCodeRegionGenerator and calls AsmCodeRegionGenerator::parseCodeRegions().
Within this function, both an MCAsmParser and MCTargetAsmParser are created so
that MCAsmParser::Run() can be used to create the code regions for us.

These parser classes were created for llvm-mc so they are designed to emit code
with an MCStreamer and MCTargetStreamer that are expected to be setup and passed
into the MCAsmParser constructor. Because llvm-mca doesn’t want to emit any
code, an MCStreamerWrapper class gets created instead and passed into the
MCAsmParser constructor. This wrapper inherits from MCStreamer and overrides
many of the emit methods to just do nothing. The exception is the
emitInstruction() method which calls Regions.addInstruction(Inst).

This works well and allows llvm-mca to utilize llvm-mc’s MCAsmParser to build
our code regions, however there are a few directives which rely on the
MCTargetStreamer. llvm-mc assumes that the MCStreamer that gets passed into the
MCAsmParser’s constructor has a valid pointer to an MCTargetStreamer. Because
llvm-mca doesn’t setup an MCTargetStreamer, when the parser encounters one of
those directives, a segfault will occur.

In x86, each one of these 7 directives will cause this segfault if they exist in
the input assembly to llvm-mca:

.cv_fpo_proc
.cv_fpo_setframe
.cv_fpo_pushreg
.cv_fpo_stackalloc
.cv_fpo_stackalign
.cv_fpo_endprologue
.cv_fpo_endproc
I haven’t looked at other targets, but I wouldn’t be surprised if some of the
other ones also have certain directives which could result in this same
segfault.

My proposed solution is to simply initialize an MCTargetStreamer after we
initialize the MCStreamerWrapper. The MCTargetStreamer requires an ostream
object, but we don’t actually want any of these directives to be emitted
anywhere, so I use an ostream created with the nulls() function. Since this
needs to happen after the MCStreamerWrapper has been initialized, it needs to
happen within the AsmCodeRegionGenerator::parseCodeRegions() function. The
MCTargetStreamer also needs an MCInstPrinter which is easiest to initialize
within the main() function of llvm-mca. So this MCInstPrinter gets constructed
within main() then passed into the parseCodeRegions() function as a parameter.
(If you feel like it would be appropriate and possible to create the
MCInstPrinter within the parseCodeRegions() function, then feel free to modify
my solution. That would stop us from having to pass it into the function and
would limit its scope / lifetime.)

My solution stops the segfault from happening and still passes all of the
current (expected) llvm-mca tests. I also added a new test for x86 that checks
for this segfault on an input that includes one of the .cv_fpo directives (this
test fails without my solution, but passes with it).

As far as I can tell, all of the functions that I modified are only called from
within llvm-mca so there shouldn’t be any worries about breaking other tools.

Differential Revision: https://reviews.llvm.org/D102709
2021-05-19 18:36:10 +01:00
Philipp Krones
632ebc4ab4 [MC] Untangle MCContext and MCObjectFileInfo
This untangles the MCContext and the MCObjectFileInfo. There is a circular
dependency between MCContext and MCObjectFileInfo. Currently this dependency
also exists during construction: You can't contruct a MOFI without a MCContext
without constructing the MCContext with a dummy version of that MOFI first.
This removes this dependency during construction. In a perfect world,
MCObjectFileInfo wouldn't depend on MCContext at all, but only be stored in the
MCContext, like other MC information. This is future work.

This also shifts/adds more information to the MCContext making it more
available to the different targets. Namely:

- TargetTriple
- ObjectFileType
- SubtargetInfo

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D101462
2021-05-05 10:03:02 -07:00
Kai Nacke
832340ca87 Fix the triple used in llvm-mca.
lookupTarget() can update the passed triple argument. This happens
when no triple is given on the command line, and the architecture
argument does not match the architecture in the default triple.

For example, passing -march=aarch64 on the command line, and the
default triple being x86_64-windows-msvc, the triple is changed
to aarch64-windows-msvc.

However, this triple is not saved, and later in the code, the
triple is constructed again from the triple name, which is the
default triple at this point. Thus the default triple is passed
to constructor of MCSubtargetInfo instance.

The triple is only used determine the object file format, and by
chance, the AArch64 target also uses the COFF file format, and
all is fine. Obviously, the AArch64 target does not support all
available binary file formats, e.g. XCOFF and GOFF, and llvm-mca
crashes in this case.

The fix is to update the triple name with the changed triple
name for the target lookup. Then the default object file format
for the architecture is used, in the example ELF.

Reviewed By: andreadb, abhina.sreeskantharajan

Differential Revision: https://reviews.llvm.org/D100992
2021-04-22 14:27:09 -04:00
Abhina Sreeskantharajan
82b3e28e83 [SystemZ][z/OS][Windows] Add new OF_TextWithCRLF flag and use this flag instead of OF_Text
Problem:
On SystemZ we need to open text files in text mode. On Windows, files opened in text mode adds a CRLF '\r\n' which may not be desirable.

Solution:
This patch adds two new flags

  - OF_CRLF which indicates that CRLF translation is used.
  - OF_TextWithCRLF = OF_Text | OF_CRLF indicates that the file is text and uses CRLF translation.

Developers should now use either the OF_Text or OF_TextWithCRLF for text files and OF_None for binary files. If the developer doesn't want carriage returns on Windows, they should use OF_Text, if they do want carriage returns on Windows, they should use OF_TextWithCRLF.

So this is the behaviour per platform with my patch:

z/OS:
OF_None: open in binary mode
OF_Text : open in text mode
OF_TextWithCRLF: open in text mode

Windows:
OF_None: open file with no carriage return
OF_Text: open file with no carriage return
OF_TextWithCRLF: open file with carriage return

The Major change is in llvm/lib/Support/Windows/Path.inc to only set text mode if the OF_CRLF is set.
```
  if (Flags & OF_CRLF)
    CrtOpenFlags |= _O_TEXT;
```

These following files are the ones that still use OF_Text which I left unchanged. I modified all these except raw_ostream.cpp in recent patches so I know these were previously in Binary mode on Windows.
./llvm/lib/Support/raw_ostream.cpp
./llvm/lib/TableGen/Main.cpp
./llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
./llvm/unittests/Support/Path.cpp
./clang/lib/StaticAnalyzer/Core/HTMLDiagnostics.cpp
./clang/lib/Frontend/CompilerInstance.cpp
./clang/lib/Driver/Driver.cpp
./clang/lib/Driver/ToolChains/Clang.cpp

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D99426
2021-04-06 07:23:31 -04:00
Andrew Savonichev
292da93d59 [MCA] Disable RCU for InOrderIssueStage
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
2021-03-24 13:54:04 +03:00
Andrew Savonichev
d791695cb5 [MCA] Add support for in-order CPUs
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
2021-03-04 14:08:19 +03:00
Wolfgang Pieb
d38be2ba0e [llvm-mca] Initial implementation of serialization using JSON. The views
implemented at this time are Summary, Timeline, ResourcePressure and InstructionInfo.
Use --json on the command line to obtain JSON output.
2021-01-21 15:15:54 -08:00
Kazu Hirata
e5b4dbab04 [llvm] Simplify string comparisons (NFC)
Identified with readability-string-compare.
2021-01-11 18:48:09 -08:00
Ella Ma
1756d67934 [llvm][clang][mlir] Add checks for the return values from Target::createXXX to prevent protential null deref
All these potential null pointer dereferences are reported by my static analyzer for null smart pointer dereferences, which has a different implementation from `alpha.cplusplus.SmartPtr`.

The checked pointers in this patch are initialized by Target::createXXX functions. When the creator function pointer is not correctly set, a null pointer will be returned, or the creator function may originally return a null pointer.

Some of them may not make sense as they may be checked before entering the function, but I fixed them all in this patch. I submit this fix because 1) similar checks are found in some other places in the LLVM codebase for the same return value of the function; and, 2) some of the pointers are dereferenced before they are checked, which may definitely trigger a null pointer dereference if the return value is nullptr.

Reviewed By: tejohnson, MaskRay, jpienaar

Differential Revision: https://reviews.llvm.org/D91410
2020-11-21 21:04:12 -08:00
serge-sans-paille
ac1d23ed7d Replace MCTargetOptionsCommandFlags.inc and CommandFlags.inc by runtime registration
MCTargetOptionsCommandFlags.inc and CommandFlags.inc are headers which contain
cl::opt with static storage.
These headers are meant to be incuded by tools to make it easier to parametrize
codegen/mc.

However, these headers are also included in at least two libraries: lldCommon
and handle-llvm. As a result, when creating DYLIB, clang-cpp holds a reference
to the options, and lldCommon holds another reference. Linking the two in a
single executable, as zig does[0], results in a double registration.

This patch explores an other approach: the .inc files are moved to regular
files, and the registration happens on-demand through static declaration of
options in the constructor of a static object.

[0] https://bugzilla.redhat.com/show_bug.cgi?id=1756977#c5

Differential Revision: https://reviews.llvm.org/D75579
2020-03-17 14:01:30 +01:00
Bill Wendling
c55cf4afa9 Revert "Remove redundant "std::move"s in return statements"
The build failed with

  error: call to deleted constructor of 'llvm::Error'

errors.

This reverts commit 1c2241a7936bf85aa68aef94bd40c3ba77d8ddf2.
2020-02-10 07:07:40 -08:00
Bill Wendling
1c2241a793 Remove redundant "std::move"s in return statements 2020-02-10 06:39:44 -08:00
Benjamin Kramer
adcd026838 Make llvm::StringRef to std::string conversions explicit.
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

This is mostly mechanical from a custom clang-tidy check, with a lot of
manual fixups. It uncovers a lot of minor inefficiencies.

This doesn't actually modify StringRef yet, I'll do that in a follow-up.
2020-01-28 23:25:25 +01:00
Fangrui Song
aa708763d3 [MC] Add parameter Address to MCInstPrinter::printInst
printInst prints a branch/call instruction as `b offset` (there are many
variants on various targets) instead of `b address`.

It is a convention to use address instead of offset in most external
symbolizers/disassemblers. This difference makes `llvm-objdump -d`
output unsatisfactory.

Add `uint64_t Address` to printInst(), so that it can pass the argument to
printInstruction(). `raw_ostream &OS` is moved to the last to be
consistent with other print* methods.

The next step is to pass `Address` to printInstruction() (generated by
tablegen from the instruction set description). We can gradually migrate
targets to print addresses instead of offsets.

In any case, downstream projects which don't know `Address` can pass 0 as
the argument.

Reviewed By: jhenderson

Differential Revision: https://reviews.llvm.org/D72172
2020-01-06 20:42:22 -08:00
Mirko Brkusanin
4b63ca1379 [Mips] Use appropriate private label prefix based on Mips ABI
MipsMCAsmInfo was using '$' prefix for Mips32 and '.L' for Mips64
regardless of -target-abi option. By passing MCTargetOptions to MCAsmInfo
we can find out Mips ABI and pick appropriate prefix.

Tags: #llvm, #clang, #lldb

Differential Revision: https://reviews.llvm.org/D66795
2019-10-23 12:24:35 +02:00
Kai Nacke
c9ddda8405 [Tools] Mark output of tools as text if it is text
Several LLVM tools write text files/streams without using OF_Text.
This can cause problems on platforms which distinguish between
text and binary output. This PR adds the OF_Text flag for the
following tools:

- llvm-dis
- llvm-dwarfdump
- llvm-mca
- llvm-mc (assembler files only)
- opt (assembler files only)
- RemarkStreamer (used e.g. by opt)

Reviewers: rnk, vivekvpandya, Bigcheese, andreadb

Differential Revision: https://reviews.llvm.org/D67696

llvm-svn: 374024
2019-10-08 08:21:20 +00:00