Commit Graph

62 Commits

Author SHA1 Message Date
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
Wenlei He 6b989a1710 [CSSPGO] Infrastructure for context-sensitive Sample PGO and Inlining
This change adds the context-senstive sample PGO infracture described in CSSPGO RFC (https://groups.google.com/g/llvm-dev/c/1p1rdYbL93s). It introduced an abstraction between input profile and profile loader that queries input profile for functions. Specifically, there's now the notion of base profile and context profile, and they are managed by the new SampleContextTracker for adjusting and merging profiles based on inline decisions. It works with top-down profiled guided inliner in profile loader (https://reviews.llvm.org/D70655) for better inlining with specialization and better post-inline profile fidelity. In the future, we can also expose this infrastructure to CGSCC inliner in order for it to take advantage of context-sensitive profile. This change is the consumption part of context-sensitive profile (The generation part is in this stack: https://reviews.llvm.org/D89707). We've seen good results internally in conjunction with Pseudo-probe (https://reviews.llvm.org/D86193). Pacthes for integration with Pseudo-probe coming up soon.

Currently the new infrastructure kick in when input profile contains the new context-sensitive profile; otherwise it's no-op and does not affect existing AutoFDO.

**Interface**

There're two sets of interfaces for query and tracking respectively exposed from SampleContextTracker. For query, now instead of simply getting a profile from input for a function, we can explicitly query base profile or context profile for given call path of a function. For tracking, there're separate APIs for marking context profile as inlined, or promoting and merging not inlined context profile.

- Query base profile (`getBaseSamplesFor`)
Base profile is the merged synthetic profile for function's CFG profile from any outstanding (not inlined) context. We can query base profile by function.

- Query context profile (`getContextSamplesFor`)
Context profile is a function's CFG profile for a given calling context. We can query context profile by context string.

- Track inlined context profile (`markContextSamplesInlined`)
When a function is inlined for given calling context, we need to mark the context profile for that context as inlined. This is to make sure we don't include inlined context profile when synthesizing base profile for that inlined function.

- Track not-inlined context profile (`promoteMergeContextSamplesTree`)
When a function is not inlined for given calling context, we need to promote the context profile tree so the not inlined context becomes top-level context. This preserve the sub-context under that function so later inline decision for that not inlined function will still have context profile for its call tree. Note that profile will be merged if needed when promoting a context profile tree if any of the node already exists at its promoted destination.

**Implementation**

Implementation-wise, `SampleContext` is created as abstraction for context. Currently it's a string for call path, and we can later optimize it to something more efficient, e.g. context id. Each `SampleContext` also has a `ContextState` indicating whether it's raw context profile from input, whether it's inlined or merged, whether it's synthetic profile created by compiler. Each `FunctionSamples` now has a `SampleContext` that tells whether it's base profile or context profile, and for context profile what is the context and state.

On top of the above context representation, a custom trie tree is implemented to track and manager context profiles. Specifically, `SampleContextTracker` is implemented that encapsulates a trie tree with `ContextTireNode` as node. Each node of the trie tree represents a frame in calling context, thus the path from root to a node represents a valid calling context. We also track `FunctionSamples` for each node, so this trie tree can serve efficient query for context profile. Accordingly, context profile tree promotion now becomes moving a subtree to be under the root of entire tree, and merge nodes for subtree if this move encounters existing nodes.

**Integration**

`SampleContextTracker` is now also integrated with AutoFDO, `SampleProfileReader` and `SampleProfileLoader`. When we detected input profile contains context-sensitive profile, `SampleContextTracker` will be used to track profiles, and all profile query will go to `SampleContextTracker` instead of `SampleProfileReader` automatically. Tracking APIs are called automatically for each inline decision from `SampleProfileLoader`.

Differential Revision: https://reviews.llvm.org/D90125
2020-12-06 11:49:18 -08:00
Hongtao Yu 64fa8cce22 [CSSPGO] Pseudo probe instrumentation pass
This change introduces a pseudo probe instrumentation pass for block instrumentation. Please refer to https://reviews.llvm.org/D86193 for the whole story.

Given the following LLVM IR:

```
define internal void @foo2(i32 %x, void (i32)* %f) !dbg !4 {
bb0:
  %cmp = icmp eq i32 %x, 0
   br i1 %cmp, label %bb1, label %bb2
bb1:
   br label %bb3
bb2:
   br label %bb3
bb3:
   ret void
}
```

The instrumented IR will look like below. Note that each llvm.pseudoprobe intrinsic call represents a pseudo probe at a block, of which the first parameter is the GUID of the probe’s owner function and the second parameter is the probe’s ID.

```
define internal void @foo2(i32 %x, void (i32)* %f) !dbg !4 {
bb0:
   %cmp = icmp eq i32 %x, 0
   call void @llvm.pseudoprobe(i64 837061429793323041, i64 1)
   br i1 %cmp, label %bb1, label %bb2
bb1:
   call void @llvm.pseudoprobe(i64 837061429793323041, i64 2)
   br label %bb3
bb2:
   call void @llvm.pseudoprobe(i64 837061429793323041, i64 3)
   br label %bb3
bb3:
   call void @llvm.pseudoprobe(i64 837061429793323041, i64 4)
   ret void
}
```

Reviewed By: wmi

Differential Revision: https://reviews.llvm.org/D86499
2020-11-30 10:16:54 -08:00
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
serge-sans-paille 95537f4508 llvmbuildectomy - compatibility with ocaml bindings
Use exact component name in add_ocaml_library.
Make expand_topologically compatible with new architecture.
Fix quoting in is_llvm_target_library.
Fix LLVMipo component name.
Write release note.
2020-11-13 14:35:52 +01:00
serge-sans-paille 9218ff50f9 llvmbuildectomy - replace llvm-build by plain cmake
No longer rely on an external tool to build the llvm component layout.

Instead, leverage the existing `add_llvm_componentlibrary` cmake function and
introduce `add_llvm_component_group` to accurately describe component behavior.

These function store extra properties in the created targets. These properties
are processed once all components are defined to resolve library dependencies
and produce the header expected by llvm-config.

Differential Revision: https://reviews.llvm.org/D90848
2020-11-13 10:35:24 +01:00
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
Jon Roelofs 3c72cafdf4 Fix missing build dependencies on omp_gen
Differential Revision: https://reviews.llvm.org/D83003
2020-07-02 07:55:20 -06:00
Johannes Doerfert 0985554b70 [Attributor][NFC] Split AbstractAttributes out of Attributor.cpp
Attributor.cpp became quite big and we need to start provide structure.
The Attributor code is now in Attributor.cpp and the classes derived
from AbstractAttribute are in AttributorAttributes.cpp. Minor changes
were required but no intended functional changes.

We also minimized includes as part of this.

Reviewed By: baziotis

Differential Revision: https://reviews.llvm.org/D76873
2020-04-08 19:02:14 -05:00
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
Tom Stellard ab411801b8 [cmake] Explicitly mark libraries defined in lib/ as "Component Libraries"
Summary:
Most libraries are defined in the lib/ directory but there are also a
few libraries defined in tools/ e.g. libLLVM, libLTO.  I'm defining
"Component Libraries" as libraries defined in lib/ that may be included in
libLLVM.so.  Explicitly marking the libraries in lib/ as component
libraries allows us to remove some fragile checks that attempt to
differentiate between lib/ libraries and tools/ libraires:

1. In tools/llvm-shlib, because
llvm_map_components_to_libnames(LIB_NAMES "all") returned a list of
all libraries defined in the whole project, there was custom code
needed to filter out libraries defined in tools/, none of which should
be included in libLLVM.so.  This code assumed that any library
defined as static was from lib/ and everything else should be
excluded.

With this change, llvm_map_components_to_libnames(LIB_NAMES, "all")
only returns libraries that have been added to the LLVM_COMPONENT_LIBS
global cmake property, so this custom filtering logic can be removed.
Doing this also fixes the build with BUILD_SHARED_LIBS=ON
and LLVM_BUILD_LLVM_DYLIB=ON.

2. There was some code in llvm_add_library that assumed that
libraries defined in lib/ would not have LLVM_LINK_COMPONENTS or
ARG_LINK_COMPONENTS set.  This is only true because libraries
defined lib lib/ use LLVMBuild.txt and don't set these values.
This code has been fixed now to check if the library has been
explicitly marked as a component library, which should now make it
easier to remove LLVMBuild at some point in the future.

I have tested this patch on Windows, MacOS and Linux with release builds
and the following combinations of CMake options:

- "" (No options)
- -DLLVM_BUILD_LLVM_DYLIB=ON
- -DLLVM_LINK_LLVM_DYLIB=ON
- -DBUILD_SHARED_LIBS=ON
- -DBUILD_SHARED_LIBS=ON -DLLVM_BUILD_LLVM_DYLIB=ON
- -DBUILD_SHARED_LIBS=ON -DLLVM_LINK_LLVM_DYLIB=ON

Reviewers: beanz, smeenai, compnerd, phosek

Reviewed By: beanz

Subscribers: wuzish, jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, mgorny, mehdi_amini, sbc100, jgravelle-google, hiraditya, aheejin, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, steven_wu, rogfer01, MartinMosbeck, brucehoult, the_o, dexonsmith, PkmX, jocewei, jsji, dang, Jim, lenary, s.egerton, pzheng, sameer.abuasal, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D70179
2019-11-21 10:48:08 -08:00
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
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 3bbf5af0ac Fix layering between SCCP and IPO SCCP
Transforms/Scalar/SCCP.cpp implemented both the Scalar and IPO SCCP, but
this meant Transforms/Scalar including Transfroms/IPO headers, creating
a circular dependency. (IPO depends on Scalar already) - so move the IPO
SCCP shims out into IPO and the basic library implementation accessible
from Scalar/SCCP.h to be used from the IPO/SCCP.cpp implementation.

llvm-svn: 328250
2018-03-22 21:41:29 +00:00
David Blaikie 0368417595 Move MetaRenamer from Transforms/UTils to Transforms/IPO since it implements part of IPO.h
llvm-svn: 328209
2018-03-22 15:57:47 +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
Easwaran Raman bdf20261d8 Add a pass to generate synthetic function entry counts.
Summary:
This pass synthesizes function entry counts by traversing the callgraph
and using the relative block frequencies of the callsites. The intended
use of these counts is in inlining to determine hot/cold callsites in
the absence of profile information.

The pass is split into two files with the code that propagates the
counts in a callgraph in a Utils file. I plan to add support for
propagation in the thinlto link phase and the propagation code will be
shared and hence this split. I did not add support to the old PM since
hot callsite determination in inlining is not possible in old PM
(although we could use hot callee heuristic with synthetic counts in the
old PM it is not worth the effort tuning it)

Reviewers: davidxl, silvas

Subscribers: mgorny, mehdi_amini, llvm-commits

Differential Revision: https://reviews.llvm.org/D41604

llvm-svn: 322110
2018-01-09 19:39:35 +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
Peter Collingbourne 1398a32e28 IPO: Introduce ThinLTOBitcodeWriter pass.
This pass prepares a module containing type metadata for ThinLTO by splitting
it into regular and thin LTO parts if possible, and writing both parts to
a multi-module bitcode file. Modules that do not contain type metadata are
written unmodified as a single module.

All globals with type metadata are added to the regular LTO module, and
the rest are added to the thin LTO module.

Differential Revision: https://reviews.llvm.org/D27324

llvm-svn: 289899
2016-12-16 00:26:30 +00:00
Chris Bieneman 05c279fc4b [CMake] NFC. Updating CMake dependency specifications
This patch updates a bunch of places where add_dependencies was being explicitly called to add dependencies on intrinsics_gen to instead use the DEPENDS named parameter. This cleanup is needed for a patch I'm working on to add a dependency debugging mode to the build system.

llvm-svn: 287206
2016-11-17 04:36:50 +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
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
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 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
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
Teresa Johnson d3a33a16bb Resubmit "Add new EliminateAvailableExternally module pass" (r239480)
This change includes a fix for https://code.google.com/p/chromium/issues/detail?id=499508#c3,
which required updating the visibility for symbols with eliminated definitions.

--Original Commit Message--

Add new EliminateAvailableExternally module pass, which is performed in
O2 compiles just before GlobalDCE, unless we are preparing for LTO.

This pass eliminates available externally globals (turning them into
declarations), regardless of whether they are dead/unreferenced, since
we are guaranteed to have a copy available elsewhere at link time.
This enables additional opportunities for GlobalDCE.

If we are preparing for LTO (e.g. a -flto -c compile), the pass is not
included as we want to preserve available externally functions for possible
link time inlining. The FE indicates whether we are doing an -flto compile
via the new PrepareForLTO flag on the PassManagerBuilder.

llvm-svn: 241466
2015-07-06 16:22:42 +00:00
Teresa Johnson 43a65d9529 Revert commit r239480 as it causes https://code.google.com/p/chromium/issues/detail?id=499508#c3.
llvm-svn: 239589
2015-06-12 03:12:00 +00:00
Teresa Johnson 232fa9af3b Add new EliminateAvailableExternally module pass, which is performed in
O2 compiles just before GlobalDCE, unless we are preparing for LTO.

This pass eliminates available externally globals (turning them into
declarations), regardless of whether they are dead/unreferenced, since
we are guaranteed to have a copy available elsewhere at link time.
This enables additional opportunities for GlobalDCE.

If we are preparing for LTO (e.g. a -flto -c compile), the pass is not
included as we want to preserve available externally functions for possible
link time inlining. The FE indicates whether we are doing an -flto compile
via the new PrepareForLTO flag on the PassManagerBuilder.

llvm-svn: 239480
2015-06-10 17:49:28 +00:00
Peter Collingbourne e6909c8e8b Introduce bitset metadata format and bitset lowering pass.
This patch introduces a new mechanism that allows IR modules to co-operatively
build pointer sets corresponding to addresses within a given set of
globals. One particular use case for this is to allow a C++ program to
efficiently verify (at each call site) that a vtable pointer is in the set
of valid vtable pointers for the class or its derived classes. One way of
doing this is for a toolchain component to build, for each class, a bit set
that maps to the memory region allocated for the vtables, such that each 1
bit in the bit set maps to a valid vtable for that class, and lay out the
vtables next to each other, to minimize the total size of the bit sets.

The patch introduces a metadata format for representing pointer sets, an
'@llvm.bitset.test' intrinsic and an LTO lowering pass that lays out the globals
and builds the bitsets, and documents the new feature.

Differential Revision: http://reviews.llvm.org/D7288

llvm-svn: 230054
2015-02-20 20:30:47 +00:00
Zachary Turner 3bd47cee78 Use ADDITIONAL_HEADER_DIRS in all LLVM CMake projects.
This allows IDEs to recognize the entire set of header files for
each of the core LLVM projects.

Differential Revision: http://reviews.llvm.org/D7526
Reviewed By: Chris Bieneman

llvm-svn: 228798
2015-02-11 03:28:02 +00:00
Duncan P. N. Exon Smith 4b4d8ecde1 Move -verify-use-list-order into llvm-uselistorder
Ugh.  Turns out not even transformation passes link in how to read IR.
I sincerely believe the buildbots will finally agree with my system
after this though.  (I don't really understand why all of this has been
working on my system, but not on all the buildbots.)

Create a new tool called llvm-uselistorder to use for verifying use-list
order.  For now, just dump everything from the (now defunct)
-verify-use-list-order pass into the tool.

This might be a better way to test use-list order anyway.

Part of PR5680.

llvm-svn: 213957
2014-07-25 17:13:03 +00:00
Duncan P. N. Exon Smith 6b6fdc992a IPO: Add use-list-order verifier
Add a -verify-use-list-order pass, which shuffles use-list order, writes
to bitcode, reads back, and verifies that the (shuffled) order matches.

  - The utility functions live in lib/IR/UseListOrder.cpp.

  - Moved (and renamed) the command-line option to enable writing
    use-lists, so that this pass can return early if the use-list orders
    aren't being serialized.

It's not clear that this pass is the right direction long-term (perhaps
a separate tool instead?), but short-term it's a great way to test the
use-list order prototype.  I've added an XFAIL-ed testcase that I'm
hoping to get working pretty quickly.

This is part of PR5680.

llvm-svn: 213945
2014-07-25 14:49:26 +00:00
Chandler Carruth e8479e15f5 Introduce a BarrierNoop pass, a hack designed to allow *some* control
over the implicitly-formed-and-nesting CGSCC pass manager and function
pass managers, especially when using them on the opt commandline or
using extension points in the module builder. The '-barrier' opt flag
(or the pass itself) will create a no-op module pass in the pipeline,
resetting the pass manager stack, and allowing the creation of a new
pipeline of function passes or CGSCC passes to be created that is
independent from any previous pipelines.

For example, this can be used to test running two CGSCC passes in
independent CGSCC pass managers as opposed to in the same CGSCC pass
manager. It also allows us to introduce a further hack into the
PassManagerBuilder to separate the O0 pipeline extension passes from the
always-inliner's CGSCC pass manager, which they likely do not want to
participate in... At the very least none of the Sanitizer passes want
this behavior.

This fixes a bug with ASan at O0 currently, and I'll commit the ASan
test which covers this pass. I'm happy to add a test case that this pass
exists and works, but not sure how much time folks would like me to
spend adding test cases for the details of its behavior of partition
pass managers.... The whole thing is just vile, and mostly intended to
unblock ASan, so I'm hoping to rip this all out in a brave new pass
manager world.

llvm-svn: 166172
2012-10-18 08:05:46 +00:00
NAKAMURA Takumi 704de074b8 llvm/lib: [CMake] Add explicit dependency to intrinsics_gen.
llvm-svn: 159112
2012-06-24 13:32:01 +00:00
Daniel Dunbar 539d0a8a09 build/CMake: Finish removal of add_llvm_library_dependencies.
llvm-svn: 145420
2011-11-29 19:25:30 +00:00
Daniel Dunbar 52823cc91c build: Attempt to rectify inconsistencies between CMake and LLVMBuild versions of explicit dependencies.
- The hope is that we have a tool/test to verify these are accurate (and tight) soon.

llvm-svn: 144444
2011-11-12 02:10:57 +00:00
Bill Wendling 2d3138c112 Remove the LowerSetJmp pass. It wasn't used effectively by any of the targets.
This is some of my original LLVM code. *wipes tear*

llvm-svn: 136821
2011-08-03 22:18:20 +00:00
Rafael Espindola 3ea478b7ac Move methods in PassManagerBuilder offline.
llvm-svn: 136727
2011-08-02 21:50:27 +00:00
Chandler Carruth 9d7feab3e0 Rewrite the CMake build to use explicit dependencies between libraries,
specified in the same file that the library itself is created. This is
more idiomatic for CMake builds, and also allows us to correctly specify
dependencies that are missed due to bugs in the GenLibDeps perl script,
or change from compiler to compiler. On Linux, this returns CMake to
a place where it can relably rebuild several targets of LLVM.

I have tried not to change the dependencies from the ones in the current
auto-generated file. The only places I've really diverged are in places
where I was seeing link failures, and added a dependency. The goal of
this patch is not to start changing the dependencies, merely to move
them into the correct location, and an explicit form that we can control
and change when necessary.

This also removes a serialization point in the build because we don't
have to scan all the libraries before we begin building various tools.
We no longer have a step of the build that regenerates a file inside the
source tree. A few other associated cleanups fall out of this.

This isn't really finished yet though. After talking to dgregor he urged
switching to a single CMake macro to construct libraries with both
sources and dependencies in the arguments. Migrating from the two macros
to that style will be a follow-up patch.

Also, llvm-config is still generated with GenLibDeps.pl, which means it
still has slightly buggy dependencies. The internal CMake
'llvm-config-like' macro uses the correct explicitly specified
dependencies however. A future patch will switch llvm-config generation
(when using CMake) to be based on these deps as well.

This may well break Windows. I'm getting a machine set up now to dig
into any failures there. If anyone can chime in with problems they see
or ideas of how to solve them for Windows, much appreciated.

llvm-svn: 136433
2011-07-29 00:14:25 +00:00
Chris Lattner b1ed91f397 Land the long talked about "type system rewrite" patch. This
patch brings numerous advantages to LLVM.  One way to look at it
is through diffstat:
 109 files changed, 3005 insertions(+), 5906 deletions(-)

Removing almost 3K lines of code is a good thing.  Other advantages
include:

1. Value::getType() is a simple load that can be CSE'd, not a mutating
   union-find operation.
2. Types a uniqued and never move once created, defining away PATypeHolder.
3. Structs can be "named" now, and their name is part of the identity that
   uniques them.  This means that the compiler doesn't merge them structurally
   which makes the IR much less confusing.
4. Now that there is no way to get a cycle in a type graph without a named
   struct type, "upreferences" go away.
5. Type refinement is completely gone, which should make LTO much MUCH faster
   in some common cases with C++ code.
6. Types are now generally immutable, so we can use "Type *" instead 
   "const Type *" everywhere.

Downsides of this patch are that it removes some functions from the C API,
so people using those will have to upgrade to (not yet added) new API.  
"LLVM 3.0" is the right time to do this.

There are still some cleanups pending after this, this patch is large enough
as-is.

llvm-svn: 134829
2011-07-09 17:41:24 +00:00
Chris Lattner e81d045d94 remove the StructRetPromotion pass. It is unused, not maintained and
has some bugs.  If this is interesting functionality, it should be 
reimplemented in the argpromotion pass.

llvm-svn: 129314
2011-04-11 23:09:44 +00:00