[WPD] Add statistics

Add statistics to count overall devirtualized targets as well as the
various types of devirtualizations applied at callsites.

Differential Revision: https://reviews.llvm.org/D1

[WPD] Add statistics

Add statistics to count overall devirtualized targets as well as the
various types of devirtualizations applied at callsites.

Differential Revision: https://reviews.llvm.org/D123152

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[test] Update some test cases to use -passes when specifying the pipeline

This updates transform test cases for
ADCE
AddDiscriminators
AggressiveInstCombine
AlignmentFromAssumptions
Argume

[test] Update some test cases to use -passes when specifying the pipeline

This updates transform test cases for
ADCE
AddDiscriminators
AggressiveInstCombine
AlignmentFromAssumptions
ArgumentPromotion
BDCE
CalledValuePropagation
DCE
Reg2Mem
WholeProgramDevirt
to use the -passes syntax when specifying the pipeline.

Given that LLVM_ENABLE_NEW_PASS_MANAGER isn't set to off (which is
a deprecated feature) the updated test cases already used the new
pass manager, but they were using the legacy syntax when specifying
the passes to run. This patch can be seen as a step toward deprecating
that interface.

This patch also removes some redundant RUN lines. Here I am
referring to test cases that had multiple RUN lines verifying both
the legacy "-passname" syntax and the new "-passes=passname" syntax.
Since we switched the default pass manager to "new PM" both RUN lines
have verified the new PM version of the pass (more or less wasting
time running the same test twice), unless LLVM_ENABLE_NEW_PASS_MANAGER
is set to "off". It is assumed that it is enough to run these tests
with the new pass manager now.

Differential Revision: https://reviews.llvm.org/D108472

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Restore "[LTO/WPD] Enable aggressive WPD under LTO option"

This restores 59733525d37cf9ad88b5021b33ecdbaf2e18911c (D71913), along
with bot fix 19c76989bb505c3117730c47df85fd3800ea2767.

The bot fail

Restore "[LTO/WPD] Enable aggressive WPD under LTO option"

This restores 59733525d37cf9ad88b5021b33ecdbaf2e18911c (D71913), along
with bot fix 19c76989bb505c3117730c47df85fd3800ea2767.

The bot failure should be fixed by D73418, committed as
af954e441a5170a75687699d91d85e0692929d43.

I also added a fix for non-x86 bot failures by requiring x86 in new test
lld/test/ELF/lto/devirt_vcall_vis_public.ll.

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Revert "[LTO/WPD] Enable aggressive WPD under LTO option"

This reverts commit 59733525d37cf9ad88b5021b33ecdbaf2e18911c.

There is a windows sanitizer bot failure in one of the cfi tests
that I will

Revert "[LTO/WPD] Enable aggressive WPD under LTO option"

This reverts commit 59733525d37cf9ad88b5021b33ecdbaf2e18911c.

There is a windows sanitizer bot failure in one of the cfi tests
that I will need some time to figure out:
http://lab.llvm.org:8011/builders/sanitizer-windows/builds/57155/steps/stage%201%20check/logs/stdio

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[LTO/WPD] Enable aggressive WPD under LTO option

Summary:
Third part in series to support Safe Whole Program Devirtualization
Enablement, see RFC here:
http://lists.llvm.org/pipermail/llvm-dev/2019-

[LTO/WPD] Enable aggressive WPD under LTO option

Summary:
Third part in series to support Safe Whole Program Devirtualization
Enablement, see RFC here:
http://lists.llvm.org/pipermail/llvm-dev/2019-December/137543.html

This patch adds type test metadata under -fwhole-program-vtables,
even for classes without hidden visibility. It then changes WPD to skip
devirtualization for a virtual function call when any of the compatible
vtables has public vcall visibility.

Additionally, internal LLVM options as well as lld and gold-plugin
options are added which enable upgrading all public vcall visibility
to linkage unit (hidden) visibility during LTO. This enables the more
aggressive WPD to kick in based on LTO time knowledge of the visibility
guarantees.

Support was added to all flavors of LTO WPD (regular, hybrid and
index-only), and to both the new and old LTO APIs.

Unfortunately it was not simple to split the first and second parts of
this part of the change (the unconditional emission of type tests and
the upgrading of the vcall visiblity) as I needed a way to upgrade the
public visibility on legacy WPD llvm assembly tests that don't include
linkage unit vcall visibility specifiers, to avoid a lot of test churn.

I also added a mechanism to LowerTypeTests that allows dropping type
test assume sequences we now aggressively insert when we invoke
distributed ThinLTO backends with null indexes, which is used in testing
mode, and which doesn't invoke the normal ThinLTO backend pipeline.

Depends on D71907 and D71911.

Reviewers: pcc, evgeny777, steven_wu, espindola

Subscribers: emaste, Prazek, inglorion, arichardson, hiraditya, MaskRay, dexonsmith, dang, davidxl, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D71913

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Revert "Temporarily Revert "Add basic loop fusion pass.""

The reversion apparently deleted the test/Transforms directory.

Will be re-reverting again.

llvm-svn: 358552

WholeProgramDevirt: generate more detailed and accurate remarks.

Summary:
Keep track of all methods for which we have devirtualized at least
one call and then print them sorted alphabetically. That

WholeProgramDevirt: generate more detailed and accurate remarks.

Summary:
Keep track of all methods for which we have devirtualized at least
one call and then print them sorted alphabetically. That allows to
avoid duplicates and also makes the order deterministic.

Add optimization names into the remarks, so that it's easier to
understand how has each method been devirtualized.

Fix a bug when wrong methods could have been reported for
tryVirtualConstProp.

Reviewers: kcc, mehdi_amini

Differential Revision: https://reviews.llvm.org/D23297

llvm-svn: 278389

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WholeProgramDevirt: print remarks with devirtualized method names.

Summary:
Chrome on Linux uses WholeProgramDevirt for speed ups, and it's
important to detect regressions on both sides: the toolcha

WholeProgramDevirt: print remarks with devirtualized method names.

Summary:
Chrome on Linux uses WholeProgramDevirt for speed ups, and it's
important to detect regressions on both sides: the toolchain,
if fewer methods get devirtualized after an update, and Chrome,
if an innocently looking change caused many hot methods become
virtual again.

The need to track devirtualized methods is not Chrome-specific,
but it's probably the only user of the pass at this time.

Reviewers: kcc

Differential Revision: https://reviews.llvm.org/D23219

llvm-svn: 277856

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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 i

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

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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 f

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

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