Commit Graph

137 Commits

Author SHA1 Message Date
Paul Kirth bac6cd5bf8 [misexpect] Re-implement MisExpect Diagnostics
Reimplements MisExpect diagnostics from D66324 to reconstruct its
original checking methodology only using MD_prof branch_weights
metadata.

New checks rely on 2 invariants:

1) For frontend instrumentation, MD_prof branch_weights will always be
   populated before llvm.expect intrinsics are lowered.

2) for IR and sample profiling, llvm.expect intrinsics will always be
   lowered before branch_weights are populated from the IR profiles.

These invariants allow the checking to assume how the existing branch
weights are populated depending on the profiling method used, and emit
the correct diagnostics. If these invariants are ever invalidated, the
MisExpect related checks would need to be updated, potentially by
re-introducing MD_misexpect metadata, and ensuring it always will be
transformed the same way as branch_weights in other optimization passes.

Frontend based profiling is now enabled without using LLVM Args, by
introducing a new CodeGen option, and checking if the -Wmisexpect flag
has been passed on the command line.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D115907
2022-04-19 21:23:48 +00:00
Jorge Gorbe Moya fc7573f29c Revert "[misexpect] Re-implement MisExpect Diagnostics"
This reverts commit 46774df307.
2022-03-31 14:54:41 -07:00
Paul Kirth 46774df307 [misexpect] Re-implement MisExpect Diagnostics
Reimplements MisExpect diagnostics from D66324 to reconstruct its
original checking methodology only using MD_prof branch_weights
metadata.

New checks rely on 2 invariants:

1) For frontend instrumentation, MD_prof branch_weights will always be
   populated before llvm.expect intrinsics are lowered.

2) for IR and sample profiling, llvm.expect intrinsics will always be
   lowered before branch_weights are populated from the IR profiles.

These invariants allow the checking to assume how the existing branch
weights are populated depending on the profiling method used, and emit
the correct diagnostics. If these invariants are ever invalidated, the
MisExpect related checks would need to be updated, potentially by
re-introducing MD_misexpect metadata, and ensuring it always will be
transformed the same way as branch_weights in other optimization passes.

Frontend based profiling is now enabled without using LLVM Args, by
introducing a new CodeGen option, and checking if the -Wmisexpect flag
has been passed on the command line.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D115907
2022-03-31 17:38:21 +00:00
Paul Kirth 90cb325abd Revert "[misexpect] Re-implement MisExpect Diagnostics"
This reverts commit 2add3fbd97.
2022-03-29 06:20:30 +00:00
Paul Kirth 2add3fbd97 [misexpect] Re-implement MisExpect Diagnostics
Reimplements MisExpect diagnostics from D66324 to reconstruct its
original checking methodology only using MD_prof branch_weights
metadata.

New checks rely on 2 invariants:

1) For frontend instrumentation, MD_prof branch_weights will always be
   populated before llvm.expect intrinsics are lowered.

2) for IR and sample profiling, llvm.expect intrinsics will always be
   lowered before branch_weights are populated from the IR profiles.

These invariants allow the checking to assume how the existing branch
weights are populated depending on the profiling method used, and emit
the correct diagnostics. If these invariants are ever invalidated, the
MisExpect related checks would need to be updated, potentially by
re-introducing MD_misexpect metadata, and ensuring it always will be
transformed the same way as branch_weights in other optimization passes.

Frontend based profiling is now enabled without using LLVM Args, by
introducing a new CodeGen option, and checking if the -Wmisexpect flag
has been passed on the command line.

Reviewed By: tejohnson

Differential Revision: https://reviews.llvm.org/D115907
2022-03-28 23:30:04 +00:00
Paul Kirth 964398ccb1 Revert "Revert "Revert "[misexpect] Re-implement MisExpect Diagnostics"""
This reverts commit 6cf560d69a.
2022-03-18 00:21:33 +00:00
Paul Kirth 6cf560d69a Revert "Revert "[misexpect] Re-implement MisExpect Diagnostics""
I mistakenly reverted my commit, so I'm relanding it.

This reverts commit 10866a1df4.
2022-03-18 00:04:22 +00:00
Paul Kirth 10866a1df4 Revert "[misexpect] Re-implement MisExpect Diagnostics"
This reverts commit e7749d4713.
2022-03-17 23:54:26 +00:00
Paul Kirth e7749d4713 [misexpect] Re-implement MisExpect Diagnostics
Reimplements MisExpect diagnostics from D66324 to reconstruct its
original checking methodology only using MD_prof branch_weights
metadata.

New checks rely on 2 invariants:

1) For frontend instrumentation, MD_prof branch_weights will always be
   populated before llvm.expect intrinsics are lowered.

2) for IR and sample profiling, llvm.expect intrinsics will always be
   lowered before branch_weights are populated from the IR profiles.

These invariants allow the checking to assume how the existing branch
weights are populated depending on the profiling method used, and emit
the correct diagnostics. If these invariants are ever invalidated, the
MisExpect related checks would need to be updated, potentially by
re-introducing MD_misexpect metadata, and ensuring it always will be
transformed the same way as branch_weights in other optimization passes.

Frontend based profiling is now enabled without using LLVM Args, by
introducing a new CodeGen option, and checking if the -Wmisexpect flag
has been passed on the command line.

Differential Revision: https://reviews.llvm.org/D115907
2022-03-17 23:46:23 +00:00
serge-sans-paille e188aae406 Cleanup header dependencies in LLVMCore
Based on the output of include-what-you-use.

This is a big chunk of changes. It is very likely to break downstream code
unless they took a lot of care in avoiding hidden ehader dependencies, something
the LLVM codebase doesn't do that well :-/

I've tried to summarize the biggest change below:

- llvm/include/llvm-c/Core.h: no longer includes llvm-c/ErrorHandling.h
- llvm/IR/DIBuilder.h no longer includes llvm/IR/DebugInfo.h
- llvm/IR/IRBuilder.h no longer includes llvm/IR/IntrinsicInst.h
- llvm/IR/LLVMRemarkStreamer.h no longer includes llvm/Support/ToolOutputFile.h
- llvm/IR/LegacyPassManager.h no longer include llvm/Pass.h
- llvm/IR/Type.h no longer includes llvm/ADT/SmallPtrSet.h
- llvm/IR/PassManager.h no longer includes llvm/Pass.h nor llvm/Support/Debug.h

And the usual count of preprocessed lines:
$ clang++ -E  -Iinclude -I../llvm/include ../llvm/lib/IR/*.cpp -std=c++14 -fno-rtti -fno-exceptions | wc -l
before: 6400831
after:  6189948

200k lines less to process is no that bad ;-)

Discourse thread on the topic: https://llvm.discourse.group/t/include-what-you-use-include-cleanup

Differential Revision: https://reviews.llvm.org/D118652
2022-02-02 06:54:20 +01:00
Craig Topper 24703cb6a4 [IR] Fix a few incorrect paths in file header comments. NFC 2021-10-15 09:18:57 -07:00
Arthur Eubanks aa53785f23 Reland [clang] Rework dontcall attributes
To avoid using the AST when emitting diagnostics, split the "dontcall"
attribute into "dontcall-warn" and "dontcall-error", and also add the
frontend attribute value as the LLVM attribute value. This gives us all
the information to report diagnostics we need from within the IR (aside
from access to the original source).

One downside is we directly use LLVM's demangler rather than using the
existing Clang diagnostic pretty printing of symbols.

Previous revisions didn't properly declare the new dependencies.

Reviewed By: nickdesaulniers

Differential Revision: https://reviews.llvm.org/D110364
2021-09-28 15:31:30 -07:00
Arthur Eubanks 7833d20f1f Revert "[clang] Rework dontcall attributes"
This reverts commit 2943071e2e.

Breaks bots
2021-09-28 14:49:27 -07:00
Arthur Eubanks 2943071e2e [clang] Rework dontcall attributes
To avoid using the AST when emitting diagnostics, split the "dontcall"
attribute into "dontcall-warn" and "dontcall-error", and also add the
frontend attribute value as the LLVM attribute value. This gives us all
the information to report diagnostics we need from within the IR (aside
from access to the original source).

One downside is we directly use LLVM's demangler rather than using the
existing Clang diagnostic pretty printing of symbols.

Reviewed By: nickdesaulniers

Differential Revision: https://reviews.llvm.org/D110364
2021-09-28 14:21:10 -07:00
Arthur Eubanks e42234383e Make DiagnosticInfoResourceLimit's limit param required
And always print it.

This makes some LLVM diagnostics match up better with Clang's diagnostics.

Updated some AMDGPU uses of DiagnosticInfoResourceLimit and now we print
better diagnostics for those.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D110204
2021-09-21 15:27:58 -07:00
Nick Desaulniers 846e562dcc [Clang] add support for error+warning fn attrs
Add support for the GNU C style __attribute__((error(""))) and
__attribute__((warning(""))). These attributes are meant to be put on
declarations of functions whom should not be called.

They are frequently used to provide compile time diagnostics similar to
_Static_assert, but which may rely on non-ICE conditions (ie. relying on
compiler optimizations). This is also similar to diagnose_if function
attribute, but can diagnose after optimizations have been run.

While users may instead simply call undefined functions in such cases to
get a linkage failure from the linker, these provide a much more
ergonomic and actionable diagnostic to users and do so at compile time
rather than at link time. Users instead may be able use inline asm .err
directives.

These are used throughout the Linux kernel in its implementation of
BUILD_BUG and BUILD_BUG_ON macros. These macros generally cannot be
converted to use _Static_assert because many of the parameters are not
ICEs. The Linux kernel still needs to be modified to make use of these
when building with Clang; I have a patch that does so I will send once
this feature is landed.

To do so, we create a new IR level Function attribute, "dontcall" (both
error and warning boil down to one IR Fn Attr).  Then, similar to calls
to inline asm, we attach a !srcloc Metadata node to call sites of such
attributed callees.

The backend diagnoses these during instruction selection, while we still
know that a call is a call (vs say a JMP that's a tail call) in an arch
agnostic manner.

The frontend then reconstructs the SourceLocation from that Metadata,
and determines whether to emit an error or warning based on the callee's
attribute.

Link: https://bugs.llvm.org/show_bug.cgi?id=16428
Link: https://github.com/ClangBuiltLinux/linux/issues/1173

Reviewed By: aaron.ballman

Differential Revision: https://reviews.llvm.org/D106030
2021-08-25 10:34:18 -07:00
Fangrui Song f53d791520 Improve the diagnostic of DiagnosticInfoResourceLimit (and warn-stack-size in particular)
Before: `warning: stack size limit exceeded (888) in main`
After: `warning: stack frame size (888) exceeds limit (100) in function 'main'` (the -Wframe-larger-than limit will be mentioned)

Reviewed By: nickdesaulniers

Differential Revision: https://reviews.llvm.org/D104667
2021-06-22 09:55:20 -07:00
Joseph Huber 2db182ff8d [Diagnostics] Allow emitting analysis and missed remarks on functions
Summary:
Currently, only `OptimizationRemarks` can be emitted using a Function.
Add constructors to allow this for `OptimizationRemarksAnalysis` and
`OptimizationRemarkMissed` as well.

Reviewed By: jdoerfert thegameg

Differential Revision: https://reviews.llvm.org/D102784
2021-05-19 15:10:20 -04:00
Yuanfang Chen 5de2d189e6 [Diagnose] Unify MCContext and LLVMContext diagnosing
The situation with inline asm/MC error reporting is kind of messy at the
moment. The errors from MC layout are not reliably propagated and users
have to specify an inlineasm handler separately to get inlineasm
diagnose. The latter issue is not a correctness issue but could be improved.

* Kill LLVMContext inlineasm diagnose handler and migrate it to use
  DiagnoseInfo/DiagnoseHandler.
* Introduce `DiagnoseInfoSrcMgr` to diagnose SourceMgr backed errors. This
  covers use cases like inlineasm, MC, and any clients using SourceMgr.
* Move AsmPrinter::SrcMgrDiagInfo and its instance to MCContext. The next step
  is to combine MCContext::SrcMgr and MCContext::InlineSrcMgr because in all
  use cases, only one of them is used.
* If LLVMContext is available, let MCContext uses LLVMContext's diagnose
  handler; if LLVMContext is not available, MCContext uses its own default
  diagnose handler which just prints SMDiagnostic.
* Change a few clients(Clang, llc, lldb) to use the new way of reporting.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D97449
2021-03-01 15:58:37 -08:00
Kazu Hirata d29562b29c [IR] Drop unnecessary const from return types (NFC)
Identified with const-return-type.
2021-02-04 21:18:02 -08:00
David Sherwood 9b76160e53 [Support] Introduce a new InstructionCost class
This is the first in a series of patches that attempts to migrate
existing cost instructions to return a new InstructionCost class
in place of a simple integer. This new class is intended to be
as light-weight and simple as possible, with a full range of
arithmetic and comparison operators that largely mirror the same
sets of operations on basic types, such as integers. The main
advantage to using an InstructionCost is that it can encode a
particular cost state in addition to a value. The initial
implementation only has two states - Normal and Invalid - but these
could be expanded over time if necessary. An invalid state can
be used to represent an unknown cost or an instruction that is
prohibitively expensive.

This patch adds the new class and changes the getInstructionCost
interface to return the new class. Other cost functions, such as
getUserCost, etc., will be migrated in future patches as I believe
this to be less disruptive. One benefit of this new class is that
it provides a way to unify many of the magic costs in the codebase
where the cost is set to a deliberately high number to prevent
optimisations taking place, e.g. vectorization. It also provides
a route to represent the extremely high, and unknown, cost of
scalarization of scalable vectors, which is not currently supported.

Differential Revision: https://reviews.llvm.org/D91174
2020-12-11 08:12:54 +00:00
Roman Lebedev 6861d938e5
Revert "clang-misexpect: Profile Guided Validation of Performance Annotations in LLVM"
See discussion in https://bugs.llvm.org/show_bug.cgi?id=45073 / https://reviews.llvm.org/D66324#2334485
the implementation is known-broken for certain inputs,
the bugreport was up for a significant amount of timer,
and there has been no activity to address it.
Therefore, just completely rip out all of misexpect handling.

I suspect, fixing it requires redesigning the internals of MD_misexpect.
Should anyone commit to fixing the implementation problem,
starting from clean slate may be better anyways.

This reverts commit 7bdad08429,
and some of it's follow-ups, that don't stand on their own.
2020-11-14 13:12:38 +03:00
Francesco Petrogalli 5a34b3ab95 [llvm][LV] Replace `unsigned VF` with `ElementCount VF` [NFCI]
Changes:

* Change `ToVectorTy` to deal directly with `ElementCount` instances.
* `VF == 1` replaced with `VF.isScalar()`.
* `VF > 1` and `VF >=2` replaced with `VF.isVector()`.
* `VF <=1` is replaced with `VF.isZero() || VF.isScalar()`.
* Replaced the uses of `llvm::SmallSet<ElementCount, ...>` with
   `llvm::SmallSetVector<ElementCount, ...>`. This avoids the need of an
   ordering function for the `ElementCount` class.
* Bits and pieces around printing the `ElementCount` to string streams.

To guarantee that this change is a NFC, `VF.Min` and asserts are used
in the following places:

1. When it doesn't make sense to deal with the scalable property, for
example:
   a. When computing unrolling factors.
   b. When shuffle masks are built for fixed width vector types
In this cases, an
assert(!VF.Scalable && "<mgs>") has been added to make sure we don't
enter coepaths that don't make sense for scalable vectors.
2. When there is a conscious decision to use `FixedVectorType`. These
uses of `FixedVectorType` will likely be removed in favour of
`VectorType` once the vectorizer is generic enough to deal with both
fixed vector types and scalable vector types.
3. When dealing with building constants out of the value of VF, for
example when computing the vectorization `step`, or building vectors
of indices. These operation _make sense_ for scalable vectors too,
but changing the code in these places to be generic and make it work
for scalable vectors is to be submitted in a separate patch, as it is
a functional change.
4. When building the potential VFs in VPlan. Making the VPlan generic
enough to handle scalable vectorization factors is a functional change
that needs a separate patch. See for example `void
LoopVectorizationPlanner::buildVPlans(unsigned MinVF, unsigned
MaxVF)`.
5. The class `IntrinsicCostAttribute`: this class still uses `unsigned
VF` as updating the field to use `ElementCount` woudl require changes
that could result in changing the behavior of the compiler. Will be done
in a separate patch.
7. When dealing with user input for forcing the vectorization
factor. In this case, adding support for scalable vectorization is a
functional change that migh require changes at command line.

Note that in some places the idiom

```
unsigned VF = ...
auto VTy = FixedVectorType::get(ScalarTy, VF)
```

has been replaced with

```
ElementCount VF = ...
assert(!VF.Scalable && ...);
auto VTy = VectorType::get(ScalarTy, VF)
```

The assertion guarantees that the new code is (at least in debug mode)
functionally equivalent to the old version. Notice that this change had been
possible because none of the methods that are specific to `FixedVectorType`
were used after the instantiation of `VTy`.

Reviewed By: rengolin, ctetreau

Differential Revision: https://reviews.llvm.org/D85794
2020-08-24 13:54:03 +00:00
Francesco Petrogalli bad7d6b373 Revert "[llvm][LV] Replace `unsigned VF` with `ElementCount VF` [NFCI]"
Reverting because the commit message doesn't reflect the one agreed on
phabricator at https://reviews.llvm.org/D85794.

This reverts commit c8d2b065b9.
2020-08-24 13:50:55 +00:00
Francesco Petrogalli c8d2b065b9 [llvm][LV] Replace `unsigned VF` with `ElementCount VF` [NFCI]
Changes:

* Change `ToVectorTy` to deal directly with `ElementCount` instances.
* `VF == 1` replaced with `VF.isScalar()`.
* `VF > 1` and `VF >=2` replaced with `VF.isVector()`.
* `VF <=1` is replaced with `VF.isZero() || VF.isScalar()`.
* Add `<` operator to `ElementCount` to be able to use
`llvm::SmallSetVector<ElementCount, ...>`.
* Bits and pieces around printing the ElementCount to string streams.
* Added a static method to `ElementCount` to represent a scalar.

To guarantee that this change is a NFC, `VF.Min` and asserts are used
in the following places:

1. When it doesn't make sense to deal with the scalable property, for
example:
   a. When computing unrolling factors.
   b. When shuffle masks are built for fixed width vector types
In this cases, an
assert(!VF.Scalable && "<mgs>") has been added to make sure we don't
enter coepaths that don't make sense for scalable vectors.
2. When there is a conscious decision to use `FixedVectorType`. These
uses of `FixedVectorType` will likely be removed in favour of
`VectorType` once the vectorizer is generic enough to deal with both
fixed vector types and scalable vector types.
3. When dealing with building constants out of the value of VF, for
example when computing the vectorization `step`, or building vectors
of indices. These operation _make sense_ for scalable vectors too,
but changing the code in these places to be generic and make it work
for scalable vectors is to be submitted in a separate patch, as it is
a functional change.
4. When building the potential VFs in VPlan. Making the VPlan generic
enough to handle scalable vectorization factors is a functional change
that needs a separate patch. See for example `void
LoopVectorizationPlanner::buildVPlans(unsigned MinVF, unsigned
MaxVF)`.
5. The class `IntrinsicCostAttribute`: this class still uses `unsigned
VF` as updating the field to use `ElementCount` woudl require changes
that could result in changing the behavior of the compiler. Will be done
in a separate patch.
7. When dealing with user input for forcing the vectorization
factor. In this case, adding support for scalable vectorization is a
functional change that migh require changes at command line.

Differential Revision: https://reviews.llvm.org/D85794
2020-08-24 13:39:42 +00:00
Jim Lin 466f8843f5 [NFC] Remove trailing space
sed -Ei 's/[[:space:]]+$//' include/**/*.{def,h,td} lib/**/*.{cpp,h,td}
2020-02-18 10:49:13 +08:00
Gabor Horvath 31ae0165c3 [LTO] Add optimization remarks for removed functions
This only works with regular LTO for now.

Differential Revision: https://reviews.llvm.org/D73597
2020-01-29 15:53:51 -08:00
Benjamin Kramer adcd026838 Make llvm::StringRef to std::string conversions explicit.
This is how it should've been and brings it more in line with
std::string_view. There should be no functional change here.

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

This doesn't actually modify StringRef yet, I'll do that in a follow-up.
2020-01-28 23:25:25 +01:00
Petr Hosek 7bdad08429 Reland "clang-misexpect: Profile Guided Validation of Performance Annotations in LLVM"
This patch contains the basic functionality for reporting potentially
incorrect usage of __builtin_expect() by comparing the developer's
annotation against a collected PGO profile. A more detailed proposal and
discussion appears on the CFE-dev mailing list
(http://lists.llvm.org/pipermail/cfe-dev/2019-July/062971.html) and a
prototype of the initial frontend changes appear here in D65300

We revised the work in D65300 by moving the misexpect check into the
LLVM backend, and adding support for IR and sampling based profiles, in
addition to frontend instrumentation.

We add new misexpect metadata tags to those instructions directly
influenced by the llvm.expect intrinsic (branch, switch, and select)
when lowering the intrinsics. The misexpect metadata contains
information about the expected target of the intrinsic so that we can
check against the correct PGO counter when emitting diagnostics, and the
compiler's values for the LikelyBranchWeight and UnlikelyBranchWeight.
We use these branch weight values to determine when to emit the
diagnostic to the user.

A future patch should address the comment at the top of
LowerExpectIntrisic.cpp to hoist the LikelyBranchWeight and
UnlikelyBranchWeight values into a shared space that can be accessed
outside of the LowerExpectIntrinsic pass. Once that is done, the
misexpect metadata can be updated to be smaller.

In the long term, it is possible to reconstruct portions of the
misexpect metadata from the existing profile data. However, we have
avoided this to keep the code simple, and because some kind of metadata
tag will be required to identify which branch/switch/select instructions
are influenced by the use of llvm.expect

Patch By: paulkirth
Differential Revision: https://reviews.llvm.org/D66324

llvm-svn: 371635
2019-09-11 16:19:50 +00:00
Dmitri Gribenko 57256af307 Revert "clang-misexpect: Profile Guided Validation of Performance Annotations in LLVM"
This reverts commit r371584. It introduced a dependency from compiler-rt
to llvm/include/ADT, which is problematic for multiple reasons.

One is that it is a novel dependency edge, which needs cross-compliation
machinery for llvm/include/ADT (yes, it is true that right now
compiler-rt included only header-only libraries, however, if we allow
compiler-rt to depend on anything from ADT, other libraries will
eventually get used).

Secondly, depending on ADT from compiler-rt exposes ADT symbols from
compiler-rt, which would cause ODR violations when Clang is built with
the profile library.

llvm-svn: 371598
2019-09-11 09:16:17 +00:00
Petr Hosek 394a8ed8f1 clang-misexpect: Profile Guided Validation of Performance Annotations in LLVM
This patch contains the basic functionality for reporting potentially
incorrect usage of __builtin_expect() by comparing the developer's
annotation against a collected PGO profile. A more detailed proposal and
discussion appears on the CFE-dev mailing list
(http://lists.llvm.org/pipermail/cfe-dev/2019-July/062971.html) and a
prototype of the initial frontend changes appear here in D65300

We revised the work in D65300 by moving the misexpect check into the
LLVM backend, and adding support for IR and sampling based profiles, in
addition to frontend instrumentation.

We add new misexpect metadata tags to those instructions directly
influenced by the llvm.expect intrinsic (branch, switch, and select)
when lowering the intrinsics. The misexpect metadata contains
information about the expected target of the intrinsic so that we can
check against the correct PGO counter when emitting diagnostics, and the
compiler's values for the LikelyBranchWeight and UnlikelyBranchWeight.
We use these branch weight values to determine when to emit the
diagnostic to the user.

A future patch should address the comment at the top of
LowerExpectIntrisic.cpp to hoist the LikelyBranchWeight and
UnlikelyBranchWeight values into a shared space that can be accessed
outside of the LowerExpectIntrinsic pass. Once that is done, the
misexpect metadata can be updated to be smaller.

In the long term, it is possible to reconstruct portions of the
misexpect metadata from the existing profile data. However, we have
avoided this to keep the code simple, and because some kind of metadata
tag will be required to identify which branch/switch/select instructions
are influenced by the use of llvm.expect

Patch By: paulkirth
Differential Revision: https://reviews.llvm.org/D66324

llvm-svn: 371584
2019-09-11 01:09:16 +00:00
Petr Hosek 7d1757aba8 Revert "clang-misexpect: Profile Guided Validation of Performance Annotations in LLVM"
This reverts commit r371484: this broke sanitizer-x86_64-linux-fast bot.

llvm-svn: 371488
2019-09-10 06:25:13 +00:00
Petr Hosek a10802fd73 clang-misexpect: Profile Guided Validation of Performance Annotations in LLVM
This patch contains the basic functionality for reporting potentially
incorrect usage of __builtin_expect() by comparing the developer's
annotation against a collected PGO profile. A more detailed proposal and
discussion appears on the CFE-dev mailing list
(http://lists.llvm.org/pipermail/cfe-dev/2019-July/062971.html) and a
prototype of the initial frontend changes appear here in D65300

We revised the work in D65300 by moving the misexpect check into the
LLVM backend, and adding support for IR and sampling based profiles, in
addition to frontend instrumentation.

We add new misexpect metadata tags to those instructions directly
influenced by the llvm.expect intrinsic (branch, switch, and select)
when lowering the intrinsics. The misexpect metadata contains
information about the expected target of the intrinsic so that we can
check against the correct PGO counter when emitting diagnostics, and the
compiler's values for the LikelyBranchWeight and UnlikelyBranchWeight.
We use these branch weight values to determine when to emit the
diagnostic to the user.

A future patch should address the comment at the top of
LowerExpectIntrisic.cpp to hoist the LikelyBranchWeight and
UnlikelyBranchWeight values into a shared space that can be accessed
outside of the LowerExpectIntrinsic pass. Once that is done, the
misexpect metadata can be updated to be smaller.

In the long term, it is possible to reconstruct portions of the
misexpect metadata from the existing profile data. However, we have
avoided this to keep the code simple, and because some kind of metadata
tag will be required to identify which branch/switch/select instructions
are influenced by the use of llvm.expect

Patch By: paulkirth
Differential Revision: https://reviews.llvm.org/D66324

llvm-svn: 371484
2019-09-10 03:11:39 +00:00
Francis Visoiu Mistrih 6ada11f134 [Remarks][NFC] Move the serialization to lib/Remarks
Separate the remark serialization to YAML from the LLVM Diagnostics.

This adds a new serialization abstraction: remarks::Serializer. It's
completely independent from lib/IR and it provides an easy way to
replace YAML by providing a new remarks::Serializer.

Differential Revision: https://reviews.llvm.org/D62632

llvm-svn: 362160
2019-05-30 21:45:59 +00:00
Francis Visoiu Mistrih 7fee2b89fd [Remarks] Add string deduplication using a string table
* Add support for uniquing strings in the remark streamer and emitting the string table in the remarks section.

* Add parsing support for the string table in the RemarkParser.

From this remark:

```
--- !Missed
Pass:     inline
Name:     NoDefinition
DebugLoc: { File: 'test-suite/SingleSource/UnitTests/2002-04-17-PrintfChar.c',
            Line: 7, Column: 3 }
Function: printArgsNoRet
Args:
  - Callee:   printf
  - String:   ' will not be inlined into '
  - Caller:   printArgsNoRet
    DebugLoc: { File: 'test-suite/SingleSource/UnitTests/2002-04-17-PrintfChar.c',
                Line: 6, Column: 0 }
  - String:   ' because its definition is unavailable'
...
```

to:

```
--- !Missed
Pass: 0
Name: 1
DebugLoc: { File: 3, Line: 7, Column: 3 }
Function: 2
Args:
  - Callee:   4
  - String:   5
  - Caller:   2
    DebugLoc: { File: 3, Line: 6, Column: 0 }
  - String:   6
...
```

And the string table in the .remarks/__remarks section containing:

```
inline\0NoDefinition\0printArgsNoRet\0
test-suite/SingleSource/UnitTests/2002-04-17-PrintfChar.c\0printf\0
will not be inlined into \0 because its definition is unavailable\0
```

This is mostly supposed to be used for testing purposes, but it gives us
a 2x reduction in the remark size, and is an incremental change for the
updates to the remarks file format.

Differential Revision: https://reviews.llvm.org/D60227

llvm-svn: 359050
2019-04-24 00:06:24 +00:00
Francis Visoiu Mistrih 6b622ebea0 Revert "[Remarks] Refactor remark diagnostic emission in a RemarkStreamer"
This reverts commit 2e8c4997a2089f8228c843fd81b148d903472e02.

Breaks bots.

llvm-svn: 355511
2019-03-06 14:52:37 +00:00
Francis Visoiu Mistrih 9052f50cb4 [Remarks] Refactor remark diagnostic emission in a RemarkStreamer
This allows us to store more info about where we're emitting the remarks
without cluttering LLVMContext. This is needed for future support for
the remark section.

Differential Revision: https://reviews.llvm.org/D58996

llvm-svn: 355507
2019-03-06 14:32:08 +00:00
Florian Hahn ca95ee5e11 [DiagnosticInfo] Add support for preserving newlines in remark arguments.
This patch adds a new type StringBlockVal which can be used to emit a
YAML block scalar, which preserves newlines in a multiline string. It
also updates  MappingTraits<DiagnosticInfoOptimizationBase::Argument> to
use it for argument values with more than a single newline.

This is helpful for remarks that want to display more in-depth
information in a more structured way.

Reviewers: thegameg, anemet

Reviewed By: anemet

Subscribers: hfinkel, hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D57159

llvm-svn: 352216
2019-01-25 16:59:06 +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
Richard Trieu a87b70d1db Add vtable anchor to classes.
llvm-svn: 350142
2018-12-29 02:02:13 +00:00
Adrian Prantl fbeeac0e1e Reapply "Adapt gcov to changes in CFE."
This reverts commit r348203 and reapplies D55085 with an additional
GCOV bugfix to make the change NFC for relative file paths in .gcno files.

Thanks to Ilya Biryukov for additional testing!

Original commit message:

    Update Diagnostic handling for changes in CFE.

    The clang frontend no longer emits the current working directory for
    DIFiles containing an absolute path in the filename: and will move the
    common prefix between current working directory and the file into the
    directory: component.

    https://reviews.llvm.org/D55085

llvm-svn: 348512
2018-12-06 18:44:48 +00:00
Ilya Biryukov 449a7f0dbb Revert "Adapt gcov to changes in CFE."
This reverts commit r348203.
Reason: this produces absolute paths in .gcno files, breaking us
internally as we rely on them being consistent with the filenames passed
in the command line.

Also reverts r348157 and r348155 to account for revert of r348154 in
clang repository.

llvm-svn: 348279
2018-12-04 16:30:31 +00:00
Adrian Prantl ff90e627ba Fix non-modular build.
llvm-svn: 348157
2018-12-03 18:07:03 +00:00
Adrian Prantl 0f873eb80a Update Diagnostic handling for changes in CFE.
The clang frontend no longer emits the current working directory for
DIFiles containing an absolute path in the filename: and will move the
common prefix between current working directory and the file into the
directory: component.

https://reviews.llvm.org/D55085

llvm-svn: 348155
2018-12-03 17:55:29 +00:00
Ashutosh Nema 007b425b77 This change add's optimization remark in LoopVersioning LICM pass.
Summary:
This patch is adding remark messages to the LoopVersioning LICM pass, 
which will be useful for optimization remark emitter (ORE) infrastructure.

Patch by: Deepak Porwal

Reviewers: anemet, ashutosh.nema, eastig

Subscribers: eastig, vivekvpandya, fhahn, llvm-commits
llvm-svn: 323183
2018-01-23 09:47:28 +00:00
Matthew Voss 3e826f4f1b Test commit
This is a commit to test commit access.

llvm-svn: 322099
2018-01-09 17:52:00 +00:00
Adam Nemet 6c381b7a2e [OptRemark] Move YAML writing to IR
Before the patch this was in Analysis.  Moving it to IR and making it implicit
part of LLVMContext::diagnose allows the full opt-remark facility to be used
outside passes e.g. the pass manager.  Jessica is planning to use this to
report function size after each pass.  The same could be used for time
reports.

Tested with BUILD_SHARED_LIBS=On.

llvm-svn: 314909
2017-10-04 15:18:11 +00:00
Adam Nemet 15fccf0009 Allow ORE.emit to take a closure to delay building the remark object
In the lambda we are now returning the remark by value so we need to preserve
its type in the insertion operator.  This requires making the insertion
operator generic.

I've also converted a few cases to use the new API.  It seems to work pretty
well.  See the LoopUnroller for a slightly more interesting case.

llvm-svn: 313691
2017-09-19 23:00:55 +00:00
Vivek Pandya b5ab895e2a This patch fixes https://bugs.llvm.org/show_bug.cgi?id=32352
It enables OptimizationRemarkEmitter::allowExtraAnalysis and MachineOptimizationRemarkEmitter::allowExtraAnalysis to return true not only for -fsave-optimization-record but when specific remarks are requested with
command line options.
The diagnostic handler used to be callback now this patch adds a class
DiagnosticHandler. It has virtual method to provide custom diagnostic handler
and methods to control which particular remarks are enabled. 
However LLVM-C API users can still provide callback function for diagnostic handler.

llvm-svn: 313390
2017-09-15 20:10:09 +00:00
Vivek Pandya df8598dcc4 This reverts r313381
llvm-svn: 313387
2017-09-15 19:53:54 +00:00