Commit Graph

53 Commits

Author SHA1 Message Date
Florian Hahn a5bb24758d [llvm-reduce] Create returns with undef values for non-void functions.
Currently replaceBranchTerminator/removeUninterestingBBsFromSwitch
always creates `ret void` instructions if no successor is in the chunk.

This results in invalid IR for functions with non-void return types,
which makes those reductions unfeasible. Instead, create `ret ty undef`
for functions with non-void return types.

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D86849
2020-08-31 16:33:46 +01:00
Florian Hahn c01a4adf99 [llvm-reduce] Add test for BB reduction with non-void ret type.
Precommit test for D86849.
2020-08-30 20:11:07 +01:00
Tyker daedfb632d [llvm-reduce] Function body reduction: don't forget to unset comdat
althought the interstingness test should usually fail when the module is invalid
this changes reduces the frequency at which llvm-reduce generate invalid IR.

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D86404
2020-08-30 12:17:33 +02:00
Florian Hahn ba7c79cb3a [llvm-reduce] Skip chunks that lead to broken modules.
Some reduction passes may create invalid IR. I am not aware of any use
case where we would like to proceed reducing invalid IR. Various utils
used here, including CloneModule, assume the module to clone is valid
and crash otherwise.

Ideally, no reduction pass would create invalid IR, but some currently
do. ReduceInstructions can be fixed relatively easily (D86210), but
others are harder. For example, ReduceBasicBlocks may remove result in
invalid PHI nodes.

For now, skip the chunks. If we get to the point where all reduction
passes result in valid IR, we may want to turn this into an assertion.

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D86212
2020-08-28 09:08:35 +01:00
Florian Hahn 51a82828fb [llvm-reduce] Skip terminators when reducing instructions.
Removing terminators will result in invalid IR, making further
reductions pointless. I do not think there is any valid use case where
we actually want to create invalid IR as part of a reduction.

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D86210
2020-08-23 17:20:34 +01:00
Roman Lebedev d4c3f20285
[Reduce] Rewrite function body delta pass again
It is not enough to replace all uses of users of the function with undef,
the users, we only drop instruction users, so they may stick around.

Let's try different approach - first drop bodies for all the functions
we will drop, which should take care of blockaddress issue the previous
rewrite was dealing with; then, after dropping *all* such bodies,
replace remaining uses with undef (thus all the uses are either
outside of functions, or are in kept functions)
and then finally drop functions.

This seems to work, and passes the *existing* test coverage,
but it is possible that a new issue will be discovered later :)

A new (previously crashing) test added.
2020-08-08 23:48:44 +03:00
Roman Lebedev 61480db601
[Reduce] Argument reduction: shoe-horn new function into remaining uses of old function
Much like with function reduction, there may be remaining unhandled uses
of function, in particular in blockaddress. And in constants we can't
RAUW it with undef, because undef is not a function.
Instead, let's try to pretent that in the remaining cases, the new
signature didn't change, by bitcasting it.

A new (previously crashing) test case added.
2020-07-27 15:39:03 +03:00
Roman Lebedev 96d74530c0
[Reduce] Argument reduction: do deal with function declarations
We can happily turn function definitions into declarations,
thus obscuring their argument from being elided by this pass.

I don't believe there is a good reason to just ignore declarations.
likely even proper llvm intrinsics ones,
at worst the input becomes uninteresting.

The other question here is that all these transforms are all-or-nothing.
In some cases, should we be treating each use separately?

The main blocker here seemed to be that llvm::CloneFunctionInto()
does `&OldFunc->front()`, which inserts a nullptr into a densemap,
which is not happy about it and asserts.
2020-07-26 01:31:56 +03:00
Roman Lebedev 9932d74740
[Reduce] Argument reduction: do properly handle invoke insts (PR46819)
replaceFunctionCalls() is very non-exhaustive, it only handles
CallInst's. Which means, by the time we drop old function,
there may still be uses of it lurking around.
Let's instead whack-a-mole them by all by replacing with undef.

I'm not sure this is the best handling, especially for calls, but IMO
poorly reduced input is much better than crashing reduction tool.
A (previously-crashing!) test added.

Fixes https://bugs.llvm.org/show_bug.cgi?id=46819
2020-07-26 01:29:00 +03:00
Roman Lebedev af1dd0b1ad
[Reduce] Basic block reduction: do properly handle invoke insts (PR46818)
Terminator may have returned value, so we need to replace uses,
and in general handle invoke as a branch inst.

I'm not sure this is the best handling, but IMO poorly reduced
input is much better than crashing reduction tool.
A (previously-crashing!) test added.

Fixes https://bugs.llvm.org/show_bug.cgi?id=46818
2020-07-26 01:28:59 +03:00
Roman Lebedev 136c8f50e9
[Reduce] Try turning function definitions into declarations first, NFCI-ish
ReduceFunctions could do it, but it also replaces *all* calls with undef,
so if any of undef replacements makes reduction uninteresting,
it won't work.

ReduceBasicBlocks also could do it, but well, it may take many guesses
for all the blocks of a function to happen to be out-of-chunk,
which is not a very efficient way to go about it.

So let's just do this first.
2020-07-25 21:43:36 +03:00
Roman Lebedev 469cb724ee
[Reduce] Rewrite runDeltaPass() workloop: do reduce a single and/or last target
Summary:
If there was a single target to begin with, because a single target
can only occupy a single chunk, we couldn't increase granularity.
and would immediately give up.

Likewise, if we had multiple targets, if by the end we'd end up with
a single target, we wouldn't finish reducing it, it would always
end up being "interesting"

Reviewers: dblaikie, nickdesaulniers, diegotf

Reviewed By: dblaikie

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D84318
2020-07-23 10:51:46 +03:00
Roman Lebedev 68922f7f2c
[NFC][Reduce] Add a test showing that we fail to to reduce single/last feature 2020-07-22 16:11:56 +03:00
Roman Lebedev 4464d90ec6
[NFC][Reduce] Rewrite remove-funcs.ll to use FileCheck, make it less fragile 2020-07-22 16:11:56 +03:00
Alex Richardson f5d4a58b4a [NFC] Use FileCheck for llvm-reduce interesness test
This makes the test added in 6187eeb683
easier to understand since you no longer have to look at another script
to see if it's doing the right thing.
2020-07-21 09:03:45 +01:00
Roman Lebedev ce052110ac
[Reduce] Argument reduction: don't try to drop terminator instructions
Newly-added test previously crashed.

While it is up for debate whether or not instruction reduction
should be indiscriminate in instruction dropping (there you can
just ensure that the test case is still -verify'ies), here
if we drop terminator, CloneFunctionInto() will immediately crash.

So let's not do that :)
2020-07-21 00:06:03 +03:00
Alex Richardson 6187eeb683 [llvm-reduce] Fix incorrect indices in argument reduction pass
The function extractArgumentsFromModule() was passing a one-based index to,
but replaceFunctionCalls() was expecting a zero-based argument index. This
resulted in assertion errors when reducing function call arguments with
different types. Additionally, the

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D84099
2020-07-19 18:06:47 +01:00
Roman Lebedev 03640ee0fa
[llvm-reduce] Reducing attributes
Summary:
This handles all three places where attributes could currently be - `GlobalVariable`, `Function` and `CallBase`.
For last two, it correctly handles all three possible attribute locations (return value, arguments and function itself)

There was a previous attempt at it D73853,
which was committed in rGfc62b36a000681c01e993242b583c5ec4ab48a3c,
but then reverted all the way back in rGb12176d2aafa0ccb2585aa218fc3b454ba84f2a9
due to some (osx?) test failures.

Reviewers: nickdesaulniers, dblaikie, diegotf, george.burgess.iv, jdoerfert, Tyker, arsenm

Reviewed By: nickdesaulniers

Subscribers: wdng, MaskRay, arsenm, llvm-commits, mgorny

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83351
2020-07-09 23:10:43 +03:00
David Blaikie 8769611f0a Remove unnecessary 'rm' in llvm-reduce tests
These were initially added to cleanup some transient/leftover files in
r372054. Now that's all cleaned up, these are no longer needed.
2020-07-09 10:49:11 -07:00
Roman Lebedev 05f2b5ccfc
[llvm-reduce] Reducing call operand bundles
Summary:
This would have been marginally useful to me during/for rG7ea46aee3670981827c04df89b2c3a1cbdc7561b.

With ongoing migration to representing assumes via operand bundles on the assume, this will be gradually more useful.

Reviewers: nickdesaulniers, diegotf, dblaikie, george.burgess.iv, jdoerfert, Tyker

Reviewed By: nickdesaulniers

Subscribers: hiraditya, mgorny, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83177
2020-07-07 01:16:37 +03:00
Roman Lebedev f804bd586e
[llvm-reduce] extractGVsFromModule(): don't crash when deleting instr twice
As it can be seen in newly-added (previously-crashing) test-case,
there can be a situation where multiple GV's are used in instr,
and we would schedule the same instruction to be deleted several times,
crashing when trying to delete it the second time.

We could either store WeakVH (done here), or use something set-like.
I think using WeakVH is prevalent in these cases elsewhere.
2020-07-05 01:01:46 +03:00
Roman Lebedev fbbb6884e1
[llvm-reduce] extractArgumentsFromModule(): don't crash when deleting instr twice
As it can be seen in newly-added (previously-crashing) test-case,
there can be a situation where multiple arguments are used in instr,
and we would schedule the same instruction to be deleted several times,
crashing when trying to delete it the second time.

We could either store WeakVH (done here), or use something set-like.
I think using WeakVH is prevalent in these cases elsewhere.
2020-07-05 00:52:42 +03:00
Nico Weber b12176d2aa Revert "[llvm-reduce] add ReduceAttribute delta pass"
This reverts commit fc62b36a00.
Breaks tests on mac: http://45.33.8.238/mac/7301/step_11.txt
2020-02-05 14:15:11 -05:00
Nick Desaulniers fc62b36a00 [llvm-reduce] add ReduceAttribute delta pass
Summary:
The output from llvm-reduce still has significantly more attributes than
bugpoint does.  Teach llvm-reduce to remove attributes.

Reviewers: diegotf, dblaikie, george.burgess.iv

Subscribers: mgorny, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73853
2020-02-05 10:05:25 -08:00
David Zarzycki 4fff87d2ee [Testing] Python 3 requires `print` to use parens
llvm-svn: 372392
2019-09-20 13:52:47 +00:00
David Blaikie 798fe477e3 llvm-reduce: Add pass to reduce instructions
Patch by Diego Treviño!

Differential Revision: https://reviews.llvm.org/D66263

llvm-svn: 372282
2019-09-19 00:59:27 +00:00
David Blaikie 070598bb52 llvm-reduce: Add pass to reduce basic blocks
Patch by Diego Treviño!

Differential Revision: https://reviews.llvm.org/D66320

llvm-svn: 372264
2019-09-18 21:45:05 +00:00
David Blaikie f27367cd32 llvm-reduce: Clean out previous test temp/output dir, since it was a dir and now it's used as just a single file
llvm-svn: 372054
2019-09-16 23:56:26 +00:00
David Blaikie cb4aee7318 llvm-reduce: Make tests shell-independent by passing the interpreter on the command line rather than using #! in the test file
llvm-svn: 372049
2019-09-16 23:41:19 +00:00
Tim Shen 396d0e1635 Fix llvm-reduce tests so that they don't assume the source code is
writable.

Instead of copying over the original file permissions, just create
a new file and add the executable bit.

llvm-svn: 371772
2019-09-12 21:03:49 +00:00
David Blaikie 6be90ac788 llvm-reduce: For now, mark these tests as requiring a shell
(since they execute shell scripts/that's the only entry point at the
moment)

llvm-svn: 371764
2019-09-12 19:50:54 +00:00
David Blaikie 890f17c256 llvm-reduce: Remove unused plugin support/requirements
llvm-svn: 371755
2019-09-12 18:52:31 +00:00
David Blaikie 5adb3d2ac0 Reapply llvm-reduce: Add pass to reduce parameters""
Fixing a couple of asan-identified bugs
* use of an invalid "Use" iterator after the element was removed
* use of StringRef to Function name after the Function was erased

This reapplies r371567, which was reverted in r371580.

llvm-svn: 371700
2019-09-12 01:20:48 +00:00
David Blaikie aaef97a55e PR43278: llvm-reduce: Use temporary file names (and ToolOutputFile) rather than unique ones - to ensure they're cleaned up
This modifies the tool somewhat to only create files when about to run
the "interestingness" test, and delete them immediately after - this
means some more files will be created sometimes (when "double checking"
work - which should probably be fixed/avoided anyway).

This now creates temporary files, rather than only unique ones, and also
uses ToolOutputFile (without ever calling "keep") to ensure the files
are deleted as soon as the interestingness test is run.

llvm-svn: 371696
2019-09-12 00:31:57 +00:00
David Blaikie d79cc14822 PR43278: Temporarily disable llvm-reduce tests due to exhausting temp files
llvm-svn: 371679
2019-09-11 22:15:16 +00:00
David Blaikie 068b362814 Revert "llvm-reduce: Add pass to reduce parameters"
Looks to be failing on asan buildbots

This reverts commit r371567.

llvm-svn: 371580
2019-09-11 00:44:17 +00:00
David Blaikie 6a2603c063 llvm-reduce: Add pass to reduce parameters
Patch by Diego Treviño!

Differential Revision: https://reviews.llvm.org/D65479

llvm-svn: 371567
2019-09-10 23:10:10 +00:00
David Blaikie 477c1df4b9 llvm-reduce: Add pass to reduce Metadata
Patch by Diego Treviño!

Differential Revision: https://reviews.llvm.org/D65026

llvm-svn: 371562
2019-09-10 22:09:58 +00:00
David Blaikie 699bea494c llvm-reduce: Simplify testing using -implicit-check-not
Also fix llvm-reduce to use the specified output file name directly,
without appending '.ll' to the name.

llvm-svn: 371555
2019-09-10 20:52:14 +00:00
David Blaikie 707be7ef9c llvm-reduce: Use %python from lit to get the correct/valid python binary for the reduction script
llvm-svn: 371143
2019-09-05 23:33:44 +00:00
Diego Trevino Ferrer 0ffe687eca [Bugpoint redesign] Added Pass to Remove Global Variables
Summary:
This pass tries to remove Global Variables, as well as their derived uses. For example if a variable `@x` is used by `%call1` and `%call2`, both these uses and the definition of `@x` are deleted. Moreover if `%call1` or `%call2` are used elsewhere those uses are also deleted, and so on recursively.

I'm still uncertain if this pass should remove derived uses, I'm open to suggestions.

Subscribers: mgorny, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64176

> llvm-svn: 368918

llvm-svn: 369061
2019-08-15 22:54:09 +00:00
Diego Trevino Ferrer c26892538e [Bugpoint redesign] Output option can now print to STDOUT
Summary:
This also changes all the outs() statements to errs() so the output and
progress streams don't get mixed.

This has been added because D64176 had flaky tests, which I believe were because the reduced file was being catted into `FileCheck`, instead of being pass from STDOUT directly.

Reviewers: chandlerc, dblaikie, xbolva00

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66314

llvm-svn: 369060
2019-08-15 22:39:43 +00:00
Diego Trevino Ferrer ef4ad1a8b6 Revert [Bugpoint redesign] Added Pass to Remove Global Variables
This reverts r368918 because it was unstable!

It broke these builds:
 * http://lab.llvm.org:8011/builders/lld-x86_64-ubuntu-fast/builds/4649
 * http://lab.llvm.org:8011/builders/clang-ppc64be-linux-lnt/builds/29966
 * http://lab.llvm.org:8011/builders/clang-ppc64be-linux-lnt/builds/29964

But surprisingly this passed:
 * http://lab.llvm.org:8011/builders/clang-ppc64be-linux-lnt/builds/29965

llvm-svn: 369039
2019-08-15 19:08:15 +00:00
Diego Trevino Ferrer 3755579f93 [Bugpoint redesign] Modified Functions pass to consider declarations
Summary: This modification was put in place so the `ReduceMetadata` pass doesn't have to consider debug functions

Reviewers: dblaikie

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66257

llvm-svn: 368934
2019-08-14 22:22:37 +00:00
Diego Trevino Ferrer d1ffcd0745 [Bugpoint redesign] Added Pass to Remove Global Variables
Summary:
This pass tries to remove Global Variables, as well as their derived uses. For example if a variable `@x` is used by `%call1` and `%call2`, both these uses and the definition of `@x` are deleted. Moreover if `%call1` or `%call2` are used elsewhere those uses are also deleted, and so on recursively.

I'm still uncertain if this pass should remove derived uses, I'm open to suggestions.

Subscribers: mgorny, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64176

llvm-svn: 368918
2019-08-14 21:01:19 +00:00
Diego Trevino Ferrer ddc64eb948 Added Delta IR Reduction Tool
Summary: Tool parses input IR file, and runs the delta debugging algorithm to reduce the functions inside the input file.

Reviewers: alexshap, chandlerc

Subscribers: mgorny, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63672

> llvm-svn: 368071

llvm-svn: 368358
2019-08-08 22:16:33 +00:00
Diego Trevino Ferrer d4d00ae6a2 Revert Added Delta IR Reduction Tool
This reverts r368071 (git commit a2584978f5bb41973d65a145b0d9459b81e3ac6d)

llvm-svn: 368217
2019-08-07 21:51:54 +00:00
Diego Trevino Ferrer b80c4c82d6 Added Delta IR Reduction Tool
Summary: Tool parses input IR file, and runs the delta debugging algorithm to reduce the functions inside the input file.

Reviewers: alexshap, chandlerc

Subscribers: mgorny, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63672

> llvm-svn: 368071

llvm-svn: 368214
2019-08-07 21:37:11 +00:00
Petr Hosek 989679c371 Reverts commit r368117, r368115 and r368112
This reverts commits:

  "Added Delta IR Reduction Tool"
  "[Bugpoint redesign] Added Pass to Remove Global Variables"
  "Added Tool as Dependency to tests & fixed warnings"

Reduce/remove-funcs.ll is failing on bots.

llvm-svn: 368122
2019-08-07 05:15:34 +00:00
Diego Trevino Ferrer 1c9ca7d101 [Bugpoint redesign] Added Pass to Remove Global Variables
Summary:
This pass tries to remove Global Variables, as well as their derived uses. For example if a variable `@x` is used by `%call1` and `%call2`, both these uses and the definition of `@x` are deleted. Moreover if `%call1` or `%call2` are used elsewhere those uses are also deleted, and so on recursively.

I'm still uncertain if this pass should remove derived uses, I'm open to suggestions.

Subscribers: mgorny, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64176

llvm-svn: 368115
2019-08-07 00:42:50 +00:00