Use this feature to fix a bug on ARM where 4 byte alignment is
incorrectly assumed.
Differential Revision: https://reviews.llvm.org/D57335
llvm-svn: 355685
Summary:
Right now, when we encounter a string equality check,
e.g. `if (memcmp(a, b, s) == 0)`, we try to expand to a comparison if `s` is a
small compile-time constant, and fall back on calling `memcmp()` else.
This is sub-optimal because memcmp has to compute much more than
equality.
This patch replaces `memcmp(a, b, s) == 0` by `bcmp(a, b, s) == 0` on platforms
that support `bcmp`.
`bcmp` can be made much more efficient than `memcmp` because equality
compare is trivially parallel while lexicographic ordering has a chain
dependency.
Subscribers: fedor.sergeev, jyknight, ckennelly, gchatelet, llvm-commits
Differential Revision: https://reviews.llvm.org/D56593
llvm-svn: 355672
Use this feature to fix a bug on ARM where 4 byte alignment is
incorrectly assumed.
Differential Revision: https://reviews.llvm.org/D57335
llvm-svn: 355585
Use this feature to fix a bug on ARM where 4 byte alignment is
incorrectly assumed.
Differential Revision: https://reviews.llvm.org/D57335
llvm-svn: 355522
Summary:
The current install-clang-headers target installs clang's resource
directory headers. This is different from the install-llvm-headers
target, which installs LLVM's API headers. We want to introduce the
corresponding target to clang, and the natural name for that new target
would be install-clang-headers. Rename the existing target to
install-clang-resource-headers to free up the install-clang-headers name
for the new target, following the discussion on cfe-dev [1].
I didn't find any bots on zorg referencing install-clang-headers. I'll
send out another PSA to cfe-dev to accompany this rename.
[1] http://lists.llvm.org/pipermail/cfe-dev/2019-February/061365.html
Reviewers: beanz, phosek, tstellar, rnk, dim, serge-sans-paille
Subscribers: mgorny, javed.absar, jdoerfert, #sanitizers, openmp-commits, lldb-commits, cfe-commits, llvm-commits
Tags: #clang, #sanitizers, #lldb, #openmp, #llvm
Differential Revision: https://reviews.llvm.org/D58791
llvm-svn: 355340
This patch adds a new flag named -bottleneck-analysis to print out information
about throughput bottlenecks.
MCA knows how to identify and classify dynamic dispatch stalls. However, it
doesn't know how to analyze and highlight kernel bottlenecks. The goal of this
patch is to teach MCA how to correlate increases in backend pressure to backend
stalls (and therefore, the loss of throughput).
From a Scheduler point of view, backend pressure is a function of the scheduler
buffer usage (i.e. how the number of uOps in the scheduler buffers changes over
time). Backend pressure increases (or decreases) when there is a mismatch
between the number of opcodes dispatched, and the number of opcodes issued in
the same cycle. Since buffer resources are limited, continuous increases in
backend pressure would eventually leads to dispatch stalls. So, there is a
strong correlation between dispatch stalls, and how backpressure changed over
time.
This patch teaches how to identify situations where backend pressure increases
due to:
- unavailable pipeline resources.
- data dependencies.
Data dependencies may delay execution of instructions and therefore increase the
time that uOps have to spend in the scheduler buffers. That often translates to
an increase in backend pressure which may eventually lead to a bottleneck.
Contention on pipeline resources may also delay execution of instructions, and
lead to a temporary increase in backend pressure.
Internally, the Scheduler classifies instructions based on whether register /
memory operands are available or not.
An instruction is marked as "ready to execute" only if data dependencies are
fully resolved.
Every cycle, the Scheduler attempts to execute all instructions that are ready
to execute. If an instruction cannot execute because of unavailable pipeline
resources, then the Scheduler internally updates a BusyResourceUnits mask with
the ID of each unavailable resource.
ExecuteStage is responsible for tracking changes in backend pressure. If backend
pressure increases during a cycle because of contention on pipeline resources,
then ExecuteStage sends a "backend pressure" event to the listeners.
That event would contain information about instructions delayed by resource
pressure, as well as the BusyResourceUnits mask.
Note that ExecuteStage also knows how to identify situations where backpressure
increased because of delays introduced by data dependencies.
The SummaryView observes "backend pressure" events and prints out a "bottleneck
report".
Example of bottleneck report:
```
Cycles with backend pressure increase [ 99.89% ]
Throughput Bottlenecks:
Resource Pressure [ 0.00% ]
Data Dependencies: [ 99.89% ]
- Register Dependencies [ 0.00% ]
- Memory Dependencies [ 99.89% ]
```
A bottleneck report is printed out only if increases in backend pressure
eventually caused backend stalls.
About the time complexity:
Time complexity is linear in the number of instructions in the
Scheduler::PendingSet.
The average slowdown tends to be in the range of ~5-6%.
For memory intensive kernels, the slowdown can be significant if flag
-noalias=false is specified. In the worst case scenario I have observed a
slowdown of ~30% when flag -noalias=false was specified.
We can definitely recover part of that slowdown if we optimize class LSUnit (by
doing extra bookkeeping to speedup queries). For now, this new analysis is
disabled by default, and it can be enabled via flag -bottleneck-analysis. Users
of MCA as a library can enable the generation of pressure events through the
constructor of ExecuteStage.
This patch partially addresses https://bugs.llvm.org/show_bug.cgi?id=37494
Differential Revision: https://reviews.llvm.org/D58728
llvm-svn: 355308
This is a small addition to arithmetic operations that improves
expressiveness of the language.
Differential Revision: https://reviews.llvm.org/D58775
llvm-svn: 355187
This patch allows all forms of values for options to be used at the end
of a group. With the fix, it is possible to follow the way GNU binutils
tools handle grouping options better. For example, the -j option can be
used with objdump in any of the following ways:
$ objdump -d -j .text a.o
$ objdump -d -j.text a.o
$ objdump -dj .text a.o
$ objdump -dj.text a.o
Differential Revision: https://reviews.llvm.org/D58711
llvm-svn: 355185
If an option, which requires a value, has a `cl::Grouping` formatting
modifier, it works well as far as it is used at the end of a group,
or as a separate argument. However, if the option appears accidentally
in the middle of a group, the program just crashes. This patch prints
an error message instead.
Differential Revision: https://reviews.llvm.org/D58499
llvm-svn: 355184
Part 2 of CSPGO changes (mostly related to ProfileSummary).
Note that I use a default parameter in setProfileSummary() and getSummary().
This is to break the dependency in clang. I will make the parameter explicit
after changing clang in a separated patch.
Differential Revision: https://reviews.llvm.org/D54175
llvm-svn: 355131
Fix https://bugs.llvm.org/show_bug.cgi?id=38583: Describe
how memcpy/memmove/memset behave when len=0. Also fix
some fallout from when the alignment parameter was
replaced by an attribute.
This closes PR38583.
Patch by RalfJung (Ralf)
Differential Revision: https://reviews.llvm.org/D57600
llvm-svn: 354911
We have all the necessary legalization, expansion and unrolling support required for the *.overflow intrinsics with vector types, so update the docs to make that clear.
Note: vectorization is not in place yet (the non-homogenous return types aren't well supported) so we still must explicitly use the vectors intrinsics and not reply on slp/loop.
Differential Revision: https://reviews.llvm.org/D58618
llvm-svn: 354821
The patch adds support for --hash-filenames to llvm-cov. This option adds md5
hash of the source path to the name of the generated .gcov file. The option is
crucial for cases where you have multiple files with the same name but can't
use --preserve-paths as resulting filenames exceed the limit.
from gcov(1):
```
-x
--hash-filenames
By default, gcov uses the full pathname of the source files to to
create an output filename. This can lead to long filenames that
can overflow filesystem limits. This option creates names of the
form source-file##md5.gcov, where the source-file component is
the final filename part and the md5 component is calculated from
the full mangled name that would have been used otherwise.
```
Patch by Igor Ignatev!
Differential Revision: https://reviews.llvm.org/D58370
llvm-svn: 354379
Use some of the wording and the motivating example from r344555. The
lack of documentation was pointed out by Roman Lebedev.
Differential Revision: https://reviews.llvm.org/D58286
llvm-svn: 354167
If you want to build clang-tools-extra with monorepo, just add it to
LLVM_ENABLE_PROJECTS like with other projects.
See also "Separating clang-tools-extra from clang in LLVM_ENABLE_PROJECTS"
on cfe-dev.
Differential Revision: https://reviews.llvm.org/D58157
llvm-svn: 354057
Add some common recipes for downstream users developing on top of the
existing git mirrors. These instructions show how to migrate local
branches to the monorepo.
Differential Revision: https://reviews.llvm.org/D56550
llvm-svn: 353713
This patch accompanies the RFC posted here:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/127239.html
This patch adds a new CallBr IR instruction to support asm-goto
inline assembly like gcc as used by the linux kernel. This
instruction is both a call instruction and a terminator
instruction with multiple successors. Only inline assembly
usage is supported today.
This also adds a new INLINEASM_BR opcode to SelectionDAG and
MachineIR to represent an INLINEASM block that is also
considered a terminator instruction.
There will likely be more bug fixes and optimizations to follow
this, but we felt it had reached a point where we would like to
switch to an incremental development model.
Patch by Craig Topper, Alexander Ivchenko, Mikhail Dvoretckii
Differential Revision: https://reviews.llvm.org/D53765
llvm-svn: 353563
Summary:
Document that libFuzzer supports Windows, how to get it,
and its limitations.
Reviewers: kcc, morehouse, rnk, metzman
Reviewed By: kcc, rnk, metzman
Subscribers: hans, rnk
Differential Revision: https://reviews.llvm.org/D57597
llvm-svn: 353551
Summary:
The RFC on moving past C++11 got good traction:
http://lists.llvm.org/pipermail/llvm-dev/2019-January/129452.html
This patch therefore bumps the toolchain versions according to our policy:
llvm.org/docs/DeveloperPolicy.html#toolchain
Subscribers: mgorny, jkorous, dexonsmith, llvm-commits, mehdi_amini, jyknight, rsmith, chandlerc, smeenai, hans, reames, lattner, lhames, erichkeane
Differential Revision: https://reviews.llvm.org/D57264
llvm-svn: 353374
A fallible iterator is one whose increment or decrement operations may fail.
This would usually be supported by replacing the ++ and -- operators with
methods that return error:
class MyFallibleIterator {
public:
// ...
Error inc();
Errro dec();
// ...
};
The downside of this style is that it no longer conforms to the C++ iterator
concept, and can not make use of standard algorithms and features such as
range-based for loops.
The fallible_iterator wrapper takes an iterator written in the style above
and adapts it to (mostly) conform with the C++ iterator concept. It does this
by providing standard ++ and -- operator implementations, returning any errors
generated via a side channel (an Error reference passed into the wrapper at
construction time), and immediately jumping the iterator to a known 'end'
value upon error. It also marks the Error as checked any time an iterator is
compared with a known end value and found to be inequal, allowing early exit
from loops without redundant error checking*.
Usage looks like:
MyFallibleIterator I = ..., E = ...;
Error Err = Error::success();
for (auto &Elem : make_fallible_range(I, E, Err)) {
// Loop body is only entered when safe.
// Early exits from loop body permitted without checking Err.
if (SomeCondition)
return;
}
if (Err)
// Handle error.
* Since failure causes a fallible iterator to jump to end, testing that a
fallible iterator is not an end value implicitly verifies that the error is a
success value, and so is equivalent to an error check.
Reviewers: dblaikie, rupprecht
Subscribers: mgorny, dexonsmith, kristina, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57618
llvm-svn: 353237
Add an intrinsic that takes 2 unsigned integers with the scale of them
provided as the third argument and performs fixed point multiplication on
them.
This is a part of implementing fixed point arithmetic in clang where some of
the more complex operations will be implemented as intrinsics.
Differential Revision: https://reviews.llvm.org/D55625
llvm-svn: 353059
Summary:
Up until the point i have looked in the source, i didn't even understood that
i can disable 'cluster' output. I have always silenced it via ` &> /dev/null`.
(And hoped it wasn't contributing much of the run time.)
While i expect that it has it's use-cases i never once needed it so far.
If i forget to silence it, console is completely flooded with that output.
How about not expecting users to opt-out of analyses,
but to explicitly specify the analyses that should be performed?
Reviewers: courbet, gchatelet
Reviewed By: courbet
Subscribers: tschuett, RKSimon, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D57648
llvm-svn: 353021
Reverting D57264 again, it looks like we're down to two bots that need fixing:
polly-amd64-linux
polly-arm-linux
They both have old versions of libstdc++ and recent clang.
llvm-svn: 352954
Summary:
The RFC on moving past C++11 got good traction:
http://lists.llvm.org/pipermail/llvm-dev/2019-January/129452.html
This patch therefore bumps the toolchain versions according to our policy:
llvm.org/docs/DeveloperPolicy.html#toolchain
Subscribers: mgorny, jkorous, dexonsmith, llvm-commits, mehdi_amini, jyknight, rsmith, chandlerc, smeenai, hans, reames, lattner, lhames, erichkeane
Differential Revision: https://reviews.llvm.org/D57264
llvm-svn: 352951
A while back, createStringError was added to provide easier construction
of StringError instances, especially with formatting options. Prior to
this patch, that the documentation only mentions the standard method of
using it. Since createStringError is slightly shorter to type, and also
provides the formatting options, this patch updates the Programmer's
Manual to use the new function in its examples, and to mention the
printf formatting options. It also fixes a small typo in one of the
examples and removes the unnecessary make_error_code call.
llvm-svn: 352846
Summary:
The RFC on moving past C++11 got good traction:
http://lists.llvm.org/pipermail/llvm-dev/2019-January/129452.html
This patch therefore bumps the toolchain versions according to our policy:
llvm.org/docs/DeveloperPolicy.html#toolchain
Subscribers: mgorny, jkorous, dexonsmith, llvm-commits, mehdi_amini, jyknight, rsmith, chandlerc, smeenai, hans, reames, lattner, lhames, erichkeane
Differential Revision: https://reviews.llvm.org/D57264
llvm-svn: 352834
Recommit r352791 after tweaking DerivedTypes.h slightly, so that gcc
doesn't choke on it, hopefully.
Original Message:
The FunctionCallee type is effectively a {FunctionType*,Value*} pair,
and is a useful convenience to enable code to continue passing the
result of getOrInsertFunction() through to EmitCall, even once pointer
types lose their pointee-type.
Then:
- update the CallInst/InvokeInst instruction creation functions to
take a Callee,
- modify getOrInsertFunction to return FunctionCallee, and
- update all callers appropriately.
One area of particular note is the change to the sanitizer
code. Previously, they had been casting the result of
`getOrInsertFunction` to a `Function*` via
`checkSanitizerInterfaceFunction`, and storing that. That would report
an error if someone had already inserted a function declaraction with
a mismatching signature.
However, in general, LLVM allows for such mismatches, as
`getOrInsertFunction` will automatically insert a bitcast if
needed. As part of this cleanup, cause the sanitizer code to do the
same. (It will call its functions using the expected signature,
however they may have been declared.)
Finally, in a small number of locations, callers of
`getOrInsertFunction` actually were expecting/requiring that a brand
new function was being created. In such cases, I've switched them to
Function::Create instead.
Differential Revision: https://reviews.llvm.org/D57315
llvm-svn: 352827
