Commit Graph

76 Commits

Author SHA1 Message Date
Nikita Popov 217e85761c [ArgPromotion] Remove legacy PM support
Support for the legacy pass manager in ArgPromotion causes
complications in D125485. As the legacy pass manager for middle-end
optimizations is unsupported, drop ArgPromotion from the legacy
pipeline, rather than introducing additional complexity to deal
with it.

Differential Revision: https://reviews.llvm.org/D128536
2022-06-27 09:42:17 +02:00
Sjoerd Meijer c4a0969b9c Function Specialization Pass
This adds a function specialization pass to LLVM. Constant parameters
like function pointers and constant globals are propagated to the callee by
specializing the function.

This is a first version with a number of limitations:
- The pass is off by default, so needs to be enabled on the command line,
- It does not handle specialization of recursive functions,
- It does not yet handle constants and constant ranges,
- Only 1 argument per function is specialised,
- The cost-model could be further looked into, and perhaps related,
- We are not yet caching analysis results.

This is based on earlier work by Matthew Simpson (D36432) and Vinay Madhusudan.
More recently this was also discussed on the list, see:

https://lists.llvm.org/pipermail/llvm-dev/2021-March/149380.html.

The motivation for this work is that function specialisation often comes up as
a reason for performance differences of generated code between LLVM and GCC,
which has this enabled by default from optimisation level -O3 and up. And while
this certainly helps a few cpu benchmark cases, this also triggers in real
world codes and is thus a generally useful transformation to have in LLVM.

Function specialisation has great potential to increase compile-times and
code-size.  The summary from some investigations with this patch is:
- Compile-time increases for short compile jobs is high relatively, but the
  increase in absolute numbers still low.
- For longer compile-jobs, the extra compile time is around 1%, and very much
  in line with GCC.
- It is difficult to blame one thing for compile-time increases: it looks like
  everywhere a little bit more time is spent processing more functions and
  instructions.
- But the function specialisation pass itself is not very expensive; it doesn't
  show up very high in the profile of the optimisation passes.

The goal of this work is to reach parity with GCC which means that eventually
we would like to get this enabled by default. But first we would like to address
some of the limitations before that.

Differential Revision: https://reviews.llvm.org/D93838
2021-06-11 09:11:29 +01:00
Joseph Huber b2ad63d3cf [OpenMP] Add OpenMPOpt as a Module pass
Summary:
This patch registers OpenMPOpt as a Module pass in addition to a CGSCC
pass. This is so certain optimzations that are sensitive to intact
call-sites can happen before inlining. The old `openmpopt` pass name is
changed to `openmp-opt-cgscc` and `openmp-opt` calls the Module pass.
The current module pass only runs a single check but will be expanded in
the future.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D99202
2021-04-20 12:28:58 -04:00
Andrew Litteken dae34463e3 [IRSim][IROutliner] Adding the extraction basics for the IROutliner.
Extracting the similar regions is the first step in the IROutliner.

Using the IRSimilarityIdentifier, we collect the SimilarityGroups and
sort them by how many instructions will be removed.  Each
IRSimilarityCandidate is used to define an OutlinableRegion.  Each
region is ordered by their occurrence in the Module and the regions that
are not compatible with previously outlined regions are discarded.

Each region is then extracted with the CodeExtractor into its own
function.

We test that correctly extract in:
test/Transforms/IROutliner/extraction.ll
test/Transforms/IROutliner/address-taken.ll
test/Transforms/IROutliner/outlining-same-globals.ll
test/Transforms/IROutliner/outlining-same-constants.ll
test/Transforms/IROutliner/outlining-different-structure.ll

Recommit of bf899e8913 fixing memory
leaks.

Reviewers: paquette, jroelofs, yroux

Differential Revision: https://reviews.llvm.org/D86975
2020-12-17 11:27:26 -06:00
Andrew Litteken a8a43b6338 Revert "[IRSim][IROutliner] Adding the extraction basics for the IROutliner."
Reverting commit due to address sanitizer errors.

> Extracting the similar regions is the first step in the IROutliner.
> 
> Using the IRSimilarityIdentifier, we collect the SimilarityGroups and
> sort them by how many instructions will be removed.  Each
> IRSimilarityCandidate is used to define an OutlinableRegion.  Each
> region is ordered by their occurrence in the Module and the regions that
> are not compatible with previously outlined regions are discarded.
> 
> Each region is then extracted with the CodeExtractor into its own
> function.
> 
> We test that correctly extract in:
> test/Transforms/IROutliner/extraction.ll
> test/Transforms/IROutliner/address-taken.ll
> test/Transforms/IROutliner/outlining-same-globals.ll
> test/Transforms/IROutliner/outlining-same-constants.ll
> test/Transforms/IROutliner/outlining-different-structure.ll
> 
> Reviewers: paquette, jroelofs, yroux
> 
> Differential Revision: https://reviews.llvm.org/D86975

This reverts commit bf899e8913.
2020-11-27 19:55:57 -06:00
Andrew Litteken bf899e8913 [IRSim][IROutliner] Adding the extraction basics for the IROutliner.
Extracting the similar regions is the first step in the IROutliner.

Using the IRSimilarityIdentifier, we collect the SimilarityGroups and
sort them by how many instructions will be removed.  Each
IRSimilarityCandidate is used to define an OutlinableRegion.  Each
region is ordered by their occurrence in the Module and the regions that
are not compatible with previously outlined regions are discarded.

Each region is then extracted with the CodeExtractor into its own
function.

We test that correctly extract in:
test/Transforms/IROutliner/extraction.ll
test/Transforms/IROutliner/address-taken.ll
test/Transforms/IROutliner/outlining-same-globals.ll
test/Transforms/IROutliner/outlining-same-constants.ll
test/Transforms/IROutliner/outlining-different-structure.ll

Reviewers: paquette, jroelofs, yroux

Differential Revision: https://reviews.llvm.org/D86975
2020-11-27 19:08:29 -06:00
Florian Hahn 8dbe44cb29 Add pass to add !annotate metadata from @llvm.global.annotations.
This patch adds a new pass to add !annotation metadata for entries in
@llvm.global.anotations, which is generated  using
__attribute__((annotate("_name"))) on functions in Clang.

This has been discussed on llvm-dev as part of
    RFC: Combining Annotation Metadata and Remarks
    http://lists.llvm.org/pipermail/llvm-dev/2020-November/146393.html

Reviewed By: thegameg

Differential Revision: https://reviews.llvm.org/D91195
2020-11-16 14:57:11 +00:00
Arthur Eubanks 8d9466a385 [BlockExtract][NewPM] Port -extract-blocks to NPM
Reviewed By: thakis

Differential Revision: https://reviews.llvm.org/D89015
2020-10-21 12:51:11 -07:00
Arthur Eubanks 518ec05a10 [LoopExtract][NewPM] Port -loop-extract to NPM
-loop-extract-single is just -loop-extract on one loop.

-loop-extract depended on -break-crit-edges and -loop-simplify in the
legacy PM, but the NPM doesn't allow specifying pass dependencies like
that, so manually add those passes to the RUN lines where necessary.

Reviewed By: asbirlea

Differential Revision: https://reviews.llvm.org/D89016
2020-10-13 22:55:42 -07:00
Florian Hahn 599955eb56 Recommit "[IPConstProp] Remove and move tests to SCCP."
This reverts commit 59d6e814ce.

The cause for the revert (3 clang tests running opt -ipconstprop) was
fixed by removing those lines.
2020-08-02 22:23:54 +01:00
Florian Hahn 59d6e814ce Revert "[IPConstProp] Remove and move tests to SCCP."
This reverts commit e77624a3be.

Looks like some clang tests manually invoke -ipconstprop via opt.....
2020-07-30 13:06:54 +01:00
Florian Hahn e77624a3be [IPConstProp] Remove and move tests to SCCP.
As far as I know, ipconstprop has not been used in years and ipsccp has
been used instead. This has the potential for confusion and sometimes
leads people to spend time finding & reporting bugs as well as
updating it to work with the latest API changes.

This patch moves the tests over to SCCP. There's one functional difference
I am aware of: ipconstprop propagates for each call-site individually, so
for functions that are called with different constant arguments it can sometimes
produce better results than ipsccp (at much higher compile-time cost).But
IPSCCP can be thought to do so as well for internal functions and as mentioned
earlier, the pass seems unused in practice (and there are no plans on working
towards enabling it anytime).

Also discussed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2020-July/143773.html

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D84447
2020-07-30 12:36:27 +01:00
Johannes Doerfert b0c77c36d2 [Attributor] Add an Attributor CGSCC pass and run it
In addition to the module pass, this patch introduces a CGSCC pass that
runs the Attributor on a strongly connected component of the call graph
(both old and new PM). The Attributor was always design to be used on a
subset of functions which makes this patch mostly mechanical.

The one change is that we give up `norecurse` deduction in the module
pass in favor of doing it during the CGSCC pass. This makes the
interfaces simpler but can be revisited if needed.

Reviewed By: hfinkel

Differential Revision: https://reviews.llvm.org/D70767
2020-02-08 21:27:34 -06:00
Johannes Doerfert 9548b74a83 [OpenMP] Introduce the OpenMPOpt transformation pass
The OpenMPOpt pass is a CGSCC pass in which OpenMP specific
optimizations can reside.

The OpenMPOpt pass uses the OpenMPKinds.def file to identify runtime
calls and their uses. This allows targeted transformations and eases
their implementation.

This initial patch deduplicates `__kmpc_global_thread_num` and
`omp_get_thread_num` calls. We can also identify arguments that are
equivalent to such a call result and use it instead. Later we can
determine "gtid" arguments based on the use in kernel functions etc.

Reviewed By: JonChesterfield

Differential Revision: https://reviews.llvm.org/D69930
2020-02-08 14:47:03 -06:00
Nikita Popov 410331869d [NewPM] Port MergeFunctions pass
This ports the MergeFunctions pass to the NewPM. This was rather
straightforward, as no analyses are used.

Additionally MergeFunctions needs to be conditionally enabled in
the PassBuilder, but I left that part out of this patch.

Differential Revision: https://reviews.llvm.org/D72537
2020-01-14 20:55:41 +01:00
Aditya Kumar a6d9d31279 [LLVM-C][Ocaml] Add MergeFunctions and DCE pass
MergeFunctions and DCE pass are missing from OCaml/C-api. This patch
adds them.

Differential Revision: https://reviews.llvm.org/D65071

Reviewers: whitequark, hiraditya, deadalnix

Reviewed By: whitequark

Subscribers: llvm-commits

Tags: #llvm

Authored by: kren1

llvm-svn: 373170
2019-09-29 16:06:22 +00:00
Robert Widmann fcf3c55a8c [LLVM-C] Improve Bindings to The Internalize Pass
Summary: Adds a binding to the internalize pass that allows the caller to pass a function pointer that acts as the visibility-preservation predicate.  Previously, one could only pass an unsigned value (not LLVMBool?) that directed the pass to consider "main" or not.

Reviewers: whitequark, deadalnix, harlanhaskins

Reviewed By: whitequark, harlanhaskins

Subscribers: kren1, hiraditya, llvm-commits, harlanhaskins

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62456

llvm-svn: 366777
2019-07-23 04:56:44 +00:00
Johannes Doerfert aade782a98 [Attributor] Pass infrastructure and fixpoint framework
NOTE: Note that no attributes are derived yet. This patch will not go in
      alone but only with others that derive attributes. The framework is
      split for review purposes.

This commit introduces the Attributor pass infrastructure and fixpoint
iteration framework. Further patches will introduce abstract attributes
into this framework.

In a nutshell, the Attributor will update instances of abstract
arguments until a fixpoint, or a "timeout", is reached. Communication
between the Attributor and the abstract attributes that are derived is
restricted to the AbstractState and AbstractAttribute interfaces.

Please see the file comment in Attributor.h for detailed information
including design decisions and typical use case. Also consider the class
documentation for Attributor, AbstractState, and AbstractAttribute.

Reviewers: chandlerc, homerdin, hfinkel, fedor.sergeev, sanjoy, spatel, nlopes, nicholas, reames

Subscribers: mehdi_amini, mgorny, hiraditya, bollu, steven_wu, dexonsmith, dang, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59918

llvm-svn: 362578
2019-06-05 03:02:24 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Aditya Kumar 801394a3d7 Hot cold splitting pass
Find cold blocks based on profile information (or optionally with static analysis).
Forward propagate profile information to all cold-blocks.
Outline a cold region.
Set calling conv and prof hint for the callsite of the outlined function.

Worked in collaboration with: Sebastian Pop <s.pop@samsung.com>
Differential Revision: https://reviews.llvm.org/D50658

llvm-svn: 341669
2018-09-07 15:03:49 +00:00
David Blaikie a373d18eb7 Transforms: Introduce Transforms/Utils.h rather than spreading the declarations amongst Scalar.h and IPO.h
Fixes layering - Transforms/Utils shouldn't depend on including a Scalar
or IPO header, because Scalar and IPO depend on Utils.

llvm-svn: 328717
2018-03-28 17:44:36 +00:00
David Blaikie 376294c23a Finish moving the IPSCCP pass from Scalar to IPO - moving the registration
llvm-svn: 328259
2018-03-22 22:07:53 +00:00
David Blaikie 2965a01e98 Move the initialization of the Meta Renamer pass over to IPO along with the rest of it that was moved in r328209
llvm-svn: 328234
2018-03-22 19:36:54 +00:00
Volkan Keles dc40be75f8 [llvm-extract] Support extracting basic blocks
Summary:
Currently, there is no way to extract a basic block from a function easily. This patch
extends llvm-extract to extract the specified basic block(s).

Reviewers: loladiro, rafael, bogner

Reviewed By: bogner

Subscribers: hintonda, mgorny, qcolombet, llvm-commits

Differential Revision: https://reviews.llvm.org/D41638

llvm-svn: 323266
2018-01-23 21:51:34 +00:00
Matthew Simpson cb58558c2f Add CalledValuePropagation pass
This patch adds a new pass for attaching !callees metadata to indirect call
sites. The pass propagates values to call sites by performing an IPSCCP-like
analysis using the generic sparse propagation solver. For indirect call sites
having a small set of possible callees, the attached metadata indicates what
those callees are. The metadata can be used to facilitate optimizations like
intersecting the function attributes of the possible callees, refining the call
graph, performing indirect call promotion, etc.

Differential Revision: https://reviews.llvm.org/D37355

llvm-svn: 316576
2017-10-25 13:40:08 +00:00
Chandler Carruth 6bda14b313 Sort the remaining #include lines in include/... and lib/....
I did this a long time ago with a janky python script, but now
clang-format has built-in support for this. I fed clang-format every
line with a #include and let it re-sort things according to the precise
LLVM rules for include ordering baked into clang-format these days.

I've reverted a number of files where the results of sorting includes
isn't healthy. Either places where we have legacy code relying on
particular include ordering (where possible, I'll fix these separately)
or where we have particular formatting around #include lines that
I didn't want to disturb in this patch.

This patch is *entirely* mechanical. If you get merge conflicts or
anything, just ignore the changes in this patch and run clang-format
over your #include lines in the files.

Sorry for any noise here, but it is important to keep these things
stable. I was seeing an increasing number of patches with irrelevant
re-ordering of #include lines because clang-format was used. This patch
at least isolates that churn, makes it easy to skip when resolving
conflicts, and gets us to a clean baseline (again).

llvm-svn: 304787
2017-06-06 11:49:48 +00:00
Peter Collingbourne f72a8d4e08 Introduce GlobalSplit pass.
This pass splits globals into elements using inrange annotations on
getelementptr indices.

Differential Revision: https://reviews.llvm.org/D22295

llvm-svn: 287178
2016-11-16 23:40:26 +00:00
Chandler Carruth 67fc52f067 [PM] Port the always inliner to the new pass manager in a much more
minimal and boring form than the old pass manager's version.

This pass does the very minimal amount of work necessary to inline
functions declared as always-inline. It doesn't support a wide array of
things that the legacy pass manager did support, but is alse ... about
20 lines of code. So it has that going for it. Notably things this
doesn't support:

- Array alloca merging
  - To support the above, bottom-up inlining with careful history
    tracking and call graph updates
- DCE of the functions that become dead after this inlining.
- Inlining through call instructions with the always_inline attribute.
  Instead, it focuses on inlining functions with that attribute.

The first I've omitted because I'm hoping to just turn it off for the
primary pass manager. If that doesn't pan out, I can add it here but it
will be reasonably expensive to do so.

The second should really be handled by running global-dce after the
inliner. I don't want to re-implement the non-trivial logic necessary to
do comdat-correct DCE of functions. This means the -O0 pipeline will
have to be at least 'always-inline,global-dce', but that seems
reasonable to me. If others are seriously worried about this I'd like to
hear about it and understand why. Again, this is all solveable by
factoring that logic into a utility and calling it here, but I'd like to
wait to do that until there is a clear reason why the existing
pass-based factoring won't work.

The final point is a serious one. I can fairly easily add support for
this, but it seems both costly and a confusing construct for the use
case of the always inliner running at -O0. This attribute can of course
still impact the normal inliner easily (although I find that
a questionable re-use of the same attribute). I've started a discussion
to sort out what semantics we want here and based on that can figure out
if it makes sense ta have this complexity at O0 or not.

One other advantage of this design is that it should be quite a bit
faster due to checking for whether the function is a viable candidate
for inlining exactly once per function instead of doing it for each call
site.

Anyways, hopefully a reasonable starting point for this pass.

Differential Revision: https://reviews.llvm.org/D23299

llvm-svn: 278896
2016-08-17 02:56:20 +00:00
Teresa Johnson 2124157102 [PM] Port FunctionImport Pass to new PM
Summary: Port FunctionImport Pass to new PM.

Reviewers: mehdi_amini, davide

Subscribers: davidxl, llvm-commits

Differential Revision: https://reviews.llvm.org/D22475

llvm-svn: 275916
2016-07-18 21:22:24 +00:00
Easwaran Raman 1832bf6aee [PM] Port PartialInlining to the new PM
Differential revision: http://reviews.llvm.org/D21699

llvm-svn: 273894
2016-06-27 16:50:18 +00:00
Peter Collingbourne 7efd750607 IR: New representation for CFI and virtual call optimization pass metadata.
The bitset metadata currently used in LLVM has a few problems:

1. It has the wrong name. The name "bitset" refers to an implementation
   detail of one use of the metadata (i.e. its original use case, CFI).
   This makes it harder to understand, as the name makes no sense in the
   context of virtual call optimization.

2. It is represented using a global named metadata node, rather than
   being directly associated with a global. This makes it harder to
   manipulate the metadata when rebuilding global variables, summarise it
   as part of ThinLTO and drop unused metadata when associated globals are
   dropped. For this reason, CFI does not currently work correctly when
   both CFI and vcall opt are enabled, as vcall opt needs to rebuild vtable
   globals, and fails to associate metadata with the rebuilt globals. As I
   understand it, the same problem could also affect ASan, which rebuilds
   globals with a red zone.

This patch solves both of those problems in the following way:

1. Rename the metadata to "type metadata". This new name reflects how
   the metadata is currently being used (i.e. to represent type information
   for CFI and vtable opt). The new name is reflected in the name for the
   associated intrinsic (llvm.type.test) and pass (LowerTypeTests).

2. Attach metadata directly to the globals that it pertains to, rather
   than using the "llvm.bitsets" global metadata node as we are doing now.
   This is done using the newly introduced capability to attach
   metadata to global variables (r271348 and r271358).

See also: http://lists.llvm.org/pipermail/llvm-dev/2016-June/100462.html

Differential Revision: http://reviews.llvm.org/D21053

llvm-svn: 273729
2016-06-24 21:21:32 +00:00
Sean Silva f5080194fd [PM] Port ReversePostOrderFunctionAttrs to the new PM
Below are my super rough notes when porting. They can probably serve as
a basic guide for porting other passes to the new PM. As I port more
passes I'll expand and generalize this and make a proper
docs/HowToPortToNewPassManager.rst document. There is also missing
documentation for general concepts and API's in the new PM which will
require some documentation.
Once there is proper documentation in place we can put up a list of
passes that have to be ported and game-ify/crowdsource the rest of the
porting (at least of the middle end; the backend is still unclear).

I will however be taking personal responsibility for ensuring that the
LLD/ELF LTO pipeline is ported in a timely fashion. The remaining passes
to be ported are (do something like
`git grep "<the string in the bullet point below>"` to find the pass):

General Scalar:
[ ] Simplify the CFG
[ ] Jump Threading
[ ] MemCpy Optimization
[ ] Promote Memory to Register
[ ] MergedLoadStoreMotion
[ ] Lazy Value Information Analysis

General IPO:
[ ] Dead Argument Elimination
[ ] Deduce function attributes in RPO

Loop stuff / vectorization stuff:
[ ] Alignment from assumptions
[ ] Canonicalize natural loops
[ ] Delete dead loops
[ ] Loop Access Analysis
[ ] Loop Invariant Code Motion
[ ] Loop Vectorization
[ ] SLP Vectorizer
[ ] Unroll loops

Devirtualization / CFI:
[ ] Cross-DSO CFI
[ ] Whole program devirtualization
[ ] Lower bitset metadata

CGSCC passes:
[ ] Function Integration/Inlining
[ ] Remove unused exception handling info
[ ] Promote 'by reference' arguments to scalars

Please let me know if you are interested in working on any of the passes
in the above list (e.g. reply to the post-commit thread for this patch).
I'll probably be tackling "General Scalar" and "General IPO" first FWIW.

Steps as I port "Deduce function attributes in RPO"
---------------------------------------------------

(note: if you are doing any work based on these notes, please leave a
note in the post-commit review thread for this commit with any
improvements / suggestions / incompleteness you ran into!)

Note: "Deduce function attributes in RPO" is a module pass.

1. Do preparatory refactoring.

Do preparatory factoring. In this case all I had to do was to pull out a static helper (r272503).
(TODO: give more advice here e.g. if pass holds state or something)

2. Rename the old pass class.

llvm/lib/Transforms/IPO/FunctionAttrs.cpp
Rename class ReversePostOrderFunctionAttrs -> ReversePostOrderFunctionAttrsLegacyPass
in preparation for adding a class ReversePostOrderFunctionAttrs as the pass in the new PM.
(edit: actually wait what? The new class name will be
ReversePostOrderFunctionAttrsPass, so it doesn't conflict. So this step is
sort of useless churn).

llvm/include/llvm/InitializePasses.h
llvm/lib/LTO/LTOCodeGenerator.cpp
llvm/lib/Transforms/IPO/IPO.cpp
llvm/lib/Transforms/IPO/FunctionAttrs.cpp
Rename initializeReversePostOrderFunctionAttrsPass -> initializeReversePostOrderFunctionAttrsLegacyPassPass
(note that the "PassPass" thing falls out of `s/ReversePostOrderFunctionAttrs/ReversePostOrderFunctionAttrsLegacyPass/`)
Note that the INITIALIZE_PASS macro is what creates this identifier name, so renaming the class requires this renaming too.

Note that createReversePostOrderFunctionAttrsPass does not need to be
renamed since its name is not generated from the class name.

3. Add the new PM pass class.

In the new PM all passes need to have their
declaration in a header somewhere, so you will often need to add a header.
In this case
llvm/include/llvm/Transforms/IPO/FunctionAttrs.h is already there because
PostOrderFunctionAttrsPass was already ported.
The file-level comment from the .cpp file can be used as the file-level
comment for the new header. You may want to tweak the wording slightly
from "this file implements" to "this file provides" or similar.

Add declaration for the new PM pass in this header:

    class ReversePostOrderFunctionAttrsPass
        : public PassInfoMixin<ReversePostOrderFunctionAttrsPass> {
    public:
      PreservedAnalyses run(Module &M, AnalysisManager<Module> &AM);
    };

Its name should end with `Pass` for consistency (note that this doesn't
collide with the names of most old PM passes). E.g. call it
`<name of the old PM pass>Pass`.

Also, move the doxygen comment from the old PM pass to the declaration of
this class in the header.
Also, include the declaration for the new PM class
`llvm/Transforms/IPO/FunctionAttrs.h` at the top of the file (in this case,
it was already done when the other pass in this file was ported).

Now define the `run` method for the new class.
The main things here are:
a) Use AM.getResult<...>(M) to get results instead of `getAnalysis<...>()`

b) If the old PM pass would have returned "false" (i.e. `Changed ==
false`), then you should return PreservedAnalyses::all();

c) In the old PM getAnalysisUsage method, observe the calls
   `AU.addPreserved<...>();`.

   In the case `Changed == true`, for each preserved analysis you should do
   call `PA.preserve<...>()` on a PreservedAnalyses object and return it.
   E.g.:

       PreservedAnalyses PA;
       PA.preserve<CallGraphAnalysis>();
       return PA;

Note that calls to skipModule/skipFunction are not supported in the new PM
currently, so optnone and optimization bisect support do not work. You can
just drop those calls for now.

4. Add the pass to the new PM pass registry to make it available in opt.

In llvm/lib/Passes/PassBuilder.cpp add a #include for your header.
`#include "llvm/Transforms/IPO/FunctionAttrs.h"`
In this case there is already an include (from when
PostOrderFunctionAttrsPass was ported).

Add your pass to llvm/lib/Passes/PassRegistry.def
In this case, I added
`MODULE_PASS("rpo-functionattrs", ReversePostOrderFunctionAttrsPass())`
The string is from the `INITIALIZE_PASS*` macros used in the old pass
manager.

Then choose a test that uses the pass and use the new PM `-passes=...` to
run it.
E.g. in this case there is a test that does:
; RUN: opt < %s -basicaa -functionattrs -rpo-functionattrs -S | FileCheck %s
I have added the line:
; RUN: opt < %s -aa-pipeline=basic-aa -passes='require<targetlibinfo>,cgscc(function-attrs),rpo-functionattrs' -S | FileCheck %s
The `-aa-pipeline=basic-aa` and
`require<targetlibinfo>,cgscc(function-attrs)` are what is needed to run
functionattrs in the new PM (note that in the new PM "functionattrs"
becomes "function-attrs" for some reason). This is just pulled from
`readattrs.ll` which contains the change from when functionattrs was ported
to the new PM.
Adding rpo-functionattrs causes the pass that was just ported to run.

llvm-svn: 272505
2016-06-12 07:48:51 +00:00
Xinliang David Li e897edbd36 [PM] Port the Sample FDO to new PM (part-1)
llvm-svn: 271062
2016-05-27 22:30:44 +00:00
Davide Italiano 344e838fea [PM] Port EliminateAvailableExternally pass to the new pass manager.
llvm-svn: 268599
2016-05-05 02:37:32 +00:00
Davide Italiano 164b9bc6fe [PM] Port ConstantMerge to the new pass manager.
llvm-svn: 268582
2016-05-05 00:51:09 +00:00
Davide Italiano 66228c4cf1 [IPO/GlobalDCE] Port to the new pass manager.
Differential Revision:  http://reviews.llvm.org/D19782

llvm-svn: 268425
2016-05-03 19:39:15 +00:00
Justin Bogner 4563a06cee PM: Port Internalize to the new pass manager
llvm-svn: 267596
2016-04-26 20:15:52 +00:00
Justin Bogner 1a07501379 PM: Port GlobalOpt to the new pass manager
llvm-svn: 267499
2016-04-26 00:28:01 +00:00
Mehdi Amini 4078709957 Refactor Internalization pass to use as a callback instead of a StringSet (NFC)
This will save a bunch of copies / initialization of intermediate
datastructure, and (hopefully) simplify the code.

This also abstract the symbol preservation mechanism outside of the
Internalization pass into the client code, which is not forced
to keep a map of strings for instance (ThinLTO will prefere hashes).

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266163
2016-04-13 04:20:32 +00:00
Chandler Carruth 9c4ed175c2 [PM] Port the PostOrderFunctionAttrs pass to the new pass manager and
convert one test to use this.

This is a particularly significant milestone because it required
a working per-function AA framework which can be queried over each
function from within a CGSCC transform pass (and additionally a module
analysis to be accessible). This is essentially *the* point of the
entire pass manager rewrite. A CGSCC transform is able to query for
multiple different function's analysis results. It works. The whole
thing appears to actually work and accomplish the original goal. While
we were able to hack function attrs and basic-aa to "work" in the old
pass manager, this port doesn't use any of that, it directly leverages
the new fundamental functionality.

For this to work, the CGSCC framework also has to support SCC-based
behavior analysis, etc. The only part of the CGSCC pass infrastructure
not sorted out at this point are the updates in the face of inlining and
running function passes that mutate the call graph.

The changes are pretty boring and boiler-plate. Most of the work was
factored into more focused preperatory patches. But this is what wires
it all together.

llvm-svn: 261203
2016-02-18 11:03:11 +00:00
Peter Collingbourne df49d1bbb2 WholeProgramDevirt: introduce.
This pass implements whole program optimization of virtual calls in cases
where we know (via bitset information) that the list of callees is fixed. This
includes the following:

- Single implementation devirtualization: if a virtual call has a single
  possible callee, replace all calls with a direct call to that callee.

- Virtual constant propagation: if the virtual function's return type is an
  integer <=64 bits and all possible callees are readnone, for each class and
  each list of constant arguments: evaluate the function, store the return
  value alongside the virtual table, and rewrite each virtual call as a load
  from the virtual table.

- Uniform return value optimization: if the conditions for virtual constant
  propagation hold and each function returns the same constant value, replace
  each virtual call with that constant.

- Unique return value optimization for i1 return values: if the conditions
  for virtual constant propagation hold and a single vtable's function
  returns 0, or a single vtable's function returns 1, replace each virtual
  call with a comparison of the vptr against that vtable's address.

Differential Revision: http://reviews.llvm.org/D16795

llvm-svn: 260312
2016-02-09 22:50:34 +00:00
Chandler Carruth 1926b70e37 [attrs] Split the late-revisit pattern for deducing norecurse in
a top-down manner into a true top-down or RPO pass over the call graph.

There are specific patterns of function attributes, notably the
norecurse attribute, which are most effectively propagated top-down
because all they us caller information.

Walk in RPO over the call graph SCCs takes the form of a module pass run
immediately after the CGSCC pass managers postorder walk of the SCCs,
trying again to deduce norerucrse for each singular SCC in the call
graph.

This removes a very legacy pass manager specific trick of using a lazy
revisit list traversed during finalization of the CGSCC pass. There is
no analogous finalization step in the new pass manager, and a lazy
revisit list is just trying to produce an RPO iteration of the call
graph. We can do that more directly if more expensively. It seems
unlikely that this will be the expensive part of any compilation though
as we never examine the function bodies here. Even in an LTO run over
a very large module, this should be a reasonable fast set of operations
over a reasonably small working set -- the function call graph itself.

In the future, if this really is a compile time performance issue, we
can look at building support for both post order and RPO traversals
directly into a pass manager that builds and maintains the PO list of
SCCs.

Differential Revision: http://reviews.llvm.org/D15785

llvm-svn: 257163
2016-01-08 10:55:52 +00:00
Chandler Carruth 3a040e6d47 [attrs] Extract the pure inference of function attributes into
a standalone pass.

There is no call graph or even interesting analysis for this part of
function attributes -- it is literally inferring attributes based on the
target library identification. As such, we can do it using a much
simpler module pass that just walks the declarations. This can also
happen much earlier in the pass pipeline which has benefits for any
number of other passes.

In the process, I've cleaned up one particular aspect of the logic which
was necessary in order to separate the two passes cleanly. It now counts
inferred attributes independently rather than just counting all the
inferred attributes as one, and the counts are more clearly explained.

The two test cases we had for this code path are both ... woefully
inadequate and copies of each other. I've kept the superset test and
updated it. We need more testing here, but I had to pick somewhere to
stop fixing everything broken I saw here.

Differential Revision: http://reviews.llvm.org/D15676

llvm-svn: 256466
2015-12-27 08:41:34 +00:00
Chandler Carruth f49f1a87ef [attrs] Split off the forced attributes utility into its own pass that
is (by default) run much earlier than FuncitonAttrs proper.

This allows forcing optnone or other widely impactful attributes. It is
also a bit simpler as the force attribute behavior needs no specific
iteration order.

I've added the pass into the default module pass pipeline and LTO pass
pipeline which mirrors where function attrs itself was being run.

Differential Revision: http://reviews.llvm.org/D15668

llvm-svn: 256465
2015-12-27 08:13:45 +00:00
Evgeniy Stepanov 67849d56c3 Cross-DSO control flow integrity (LLVM part).
An LTO pass that generates a __cfi_check() function that validates a
call based on a hash of the call-site-known type and the target
pointer.

llvm-svn: 255693
2015-12-15 23:00:08 +00:00
Mehdi Amini 42418aba58 Add a FunctionImporter helper to perform summary-based cross-module function importing
Summary:
This is a helper to perform cross-module import for ThinLTO. Right now
it is importing naively every possible called functions.

Reviewers: tejohnson

Subscribers: dexonsmith, llvm-commits

Differential Revision: http://reviews.llvm.org/D14914

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 253954
2015-11-24 06:07:49 +00:00
Justin Bogner 21e153748a [PM] Port StripDeadPrototypes to the new pass manager
This is a really straightforward port. Also adds a test for the pass,
since it only seemed to be tested tangentially before.

llvm-svn: 251726
2015-10-30 23:28:12 +00:00
Justin Bogner 48f1f885e3 Whitespace. NFC
llvm-svn: 251724
2015-10-30 23:02:38 +00:00
Diego Novillo 4d71113cdb Convert SampleProfile pass into a Module pass.
Eventually, we will need sample profiles to be incorporated into the
inliner's cost models.  To do this, we need the sample profile pass to
be a module pass.

This patch makes no functional changes beyond the mechanical adjustments
needed to run SampleProfile as a module pass.

llvm-svn: 245940
2015-08-25 15:25:11 +00:00
Rafael Espindola 237c3a6def Don't change the visibility when converting a definition to a declaration.
llvm-svn: 242030
2015-07-13 14:18:22 +00:00