Commit Graph

622 Commits

Author SHA1 Message Date
Abhina Sreeskantharajan 3be2ba0ba3 [SystemZ][z/OS][Windows] Add new functions that set Text/Binary mode for Stdin and Stdout based on OpenFlags
On Windows, we want to open a file in Binary mode if OF_CRLF bit is not set. On z/OS, we want to open a file in Binary mode if the OF_Text bit is not set.

This patch creates two new functions called ChangeStdinMode and ChangeStdoutMode which will take OpenFlags as an arg to determine which mode to set stdin and stdout to. This will enable patches like https://reviews.llvm.org/D100056 to not affect Windows when setting the OF_Text flag for raw_fd_streams.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D100130
2021-04-16 08:09:19 -04:00
Duncan P. N. Exon Smith 0db6488a77 Support: Add move semantics to mapped_file_region
Update llvm::sys::fs::mapped_file_region to have a move constructor and
a move assignment operator, allowing it to be used as an Optional. Also,
update FileOutputBuffer's OnDiskBuffer to take advantage of this,
avoiding an extra allocation from the unique_ptr.

A nice follow-up would be to make the mapped_file_region constructor
private and replace its use with a factory function, such as
mapped_file_region::create(), that returns an Expected (or ErrorOr). I
don't plan on doing that immediately, but I might swing back later.

No functionality change, besides the saved allocation in OnDiskBuffer.

Differential Revision: https://reviews.llvm.org/D100159
2021-04-09 17:56:26 -07:00
Duncan P. N. Exon Smith 365053d2a5 Support: Remove code duplication for mapped_file_region accessors, NFC 2021-04-09 11:49:40 -07:00
Paul Robinson 04b3c8c52c Pass -fcrash-diagnostics-dir along to LLVM
This allows frontend and backend diagnostic files to all go into the
same place.  Have it control the Windows (mini-)dump location.

Differential Revision: https://reviews.llvm.org/D99199
2021-04-06 09:30:52 -07:00
Abhina Sreeskantharajan 82b3e28e83 [SystemZ][z/OS][Windows] Add new OF_TextWithCRLF flag and use this flag instead of OF_Text
Problem:
On SystemZ we need to open text files in text mode. On Windows, files opened in text mode adds a CRLF '\r\n' which may not be desirable.

Solution:
This patch adds two new flags

  - OF_CRLF which indicates that CRLF translation is used.
  - OF_TextWithCRLF = OF_Text | OF_CRLF indicates that the file is text and uses CRLF translation.

Developers should now use either the OF_Text or OF_TextWithCRLF for text files and OF_None for binary files. If the developer doesn't want carriage returns on Windows, they should use OF_Text, if they do want carriage returns on Windows, they should use OF_TextWithCRLF.

So this is the behaviour per platform with my patch:

z/OS:
OF_None: open in binary mode
OF_Text : open in text mode
OF_TextWithCRLF: open in text mode

Windows:
OF_None: open file with no carriage return
OF_Text: open file with no carriage return
OF_TextWithCRLF: open file with carriage return

The Major change is in llvm/lib/Support/Windows/Path.inc to only set text mode if the OF_CRLF is set.
```
  if (Flags & OF_CRLF)
    CrtOpenFlags |= _O_TEXT;
```

These following files are the ones that still use OF_Text which I left unchanged. I modified all these except raw_ostream.cpp in recent patches so I know these were previously in Binary mode on Windows.
./llvm/lib/Support/raw_ostream.cpp
./llvm/lib/TableGen/Main.cpp
./llvm/tools/dsymutil/DwarfLinkerForBinary.cpp
./llvm/unittests/Support/Path.cpp
./clang/lib/StaticAnalyzer/Core/HTMLDiagnostics.cpp
./clang/lib/Frontend/CompilerInstance.cpp
./clang/lib/Driver/Driver.cpp
./clang/lib/Driver/ToolChains/Clang.cpp

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D99426
2021-04-06 07:23:31 -04:00
Markus Böck c6047101ad [Support][Windows] Make sure only executables are found by sys::findProgramByName
The function utilizes Windows' SearchPathW function, which as I found out today, may also return directories. After looking at the Unix implementation of the file I found that it contains a check whether the found path is also executable. While fixing the Windows implementation, I also learned that sys::fs::access returns successfully when querying whether directories are executable, which the Unix version does not.

This patch makes both of these functions equivalent to their Unix implementation and insures that any path returned by sys::findProgramByName on Windows may only be executable, just like the Unix implementation.

The equivalent additions I have made to the Windows implementation, in the Unix implementation are here:
sys::findProgramByName: 39ecfe6143/llvm/lib/Support/Unix/Program.inc (L90)
sys::fs::access: c2a84771bb/llvm/lib/Support/Unix/Path.inc (L608)

I encountered this issue when running the LLVM testsuite. Commands of the form not test ... would fail to correctly execute test.exe, which is part of GnuWin32, as it actually tried to execute a folder called test, which happened to be in a directory on my PATH.

Differential Revision: https://reviews.llvm.org/D99357
2021-03-25 20:29:43 +01:00
Alexandre Ganea 64ab2b6825 [Support] Fix 'keeping' temporary files on Windows 7
As reported here: https://bugs.llvm.org/show_bug.cgi?id=48378#c0
and here: https://github.com/rust-lang/rust/issues/81051
since 79657e2339, some programs such as llvm-ar
don't work properly on Windows 7.

The issue is shown in the snippet by Oleksandr Prodan:
https://pastebin.com/v51m3uBU

In essence, once the 'DeleteFile' flag has been set on FILE_DISPOSITION_INFO,
the file path can't be queried anymore with GetFinalPathNameByHandleW. This
however works on Windows 10, GetFinalPathNameByHandleW would return sucessfully.

To workaround the issue, we simply reset the 'DeleteFile' flag before even
checking if we're dealing with a network file.

Tested with `llvm-ar r empty.a a.obj` ran on a network mount. At the moment, we
cannot specifically add a test coverage for this, since it requres mounting a
network drive.
2021-03-24 12:47:08 -04:00
Alexandre Ganea 4fcb25583c Re-land [Support] On Windows, take the affinity mask into account
The number of hardware threads available to a ThreadPool can be limited if setting an affinity mask.
For example:

    > start /B /AFFINITY 0xF lld-link.exe ...

Would let LLD only use 4 hyper-threads.

Previously, there was an outstanding issue on Windows Server 2019 on dual-CPU machines, which was preventing from using both CPU sockets. In normal conditions, when no affinity mask was set, ProcessorGroup::AllThreads was different from ProcessorGroup::UsableThreads. The previous code in llvm/lib/Support/Windows/Threading.inc L201 was improperly assuming those two values to be equal, and consequently was limiting the execution to only one CPU socket.

Differential Revision: https://reviews.llvm.org/D92419
2021-01-14 17:03:22 -05:00
Alexandre Ganea eec856848c Revert "[Support] On Windows, take the affinity mask into account"
This reverts commit 336ab2d51d.
2021-01-13 21:34:54 -05:00
Alexandre Ganea 336ab2d51d [Support] On Windows, take the affinity mask into account
The number of hardware threads available to a ThreadPool can be limited if setting an affinity mask.
For example:

> start /B /AFFINITY 0xF lld-link.exe ...

Would let LLD only use 4 hyper-threads.

Previously, there was an outstanding issue on Windows Server 2019 on dual-CPU machines, which was preventing from using both CPU sockets. In normal conditions, when no affinity mask was set, ProcessorGroup::AllThreads was different from ProcessorGroup::UsableThreads. The previous code in llvm/lib/Support/Windows/Threading.inc L201 was improperly assuming those two values to be equal, and consequently was limiting the execution to only one CPU socket.

Differential Revision: https://reviews.llvm.org/D92419
2021-01-13 21:00:09 -05:00
Kazu Hirata 1d0bc05551 [llvm] Use llvm::append_range (NFC) 2021-01-06 18:27:33 -08:00
Duncan P. N. Exon Smith 90966daac3 Support: Avoid SmallVector::assign with a range from to-be-replaced vector in Windows GetExecutableName
This code wasn't valid, and 5abf76fbe3
started asserting. This is a speculative fix since I don't have a
Windows machine handy.
2020-11-18 17:55:49 -08:00
Ronald Wampler 79657e2339 [Support] PR42623: Avoid setting the delete-on-close bit if a TempFile doesn't reside on a local drive
On Windows, after commit 881ba10465, tools
using TempFile would error with "bad file descriptor" when writing the
file on a network drive. It appears that setting the delete-on-close bit via
SetFileInformationByHandle/FileDispositionInfo prevented it from
accessing the file on network drives, and although using
FILE_DISPOSITION_INFO seems to work, it causes other troubles.

Differential Revision: https://reviews.llvm.org/D81803
2020-10-30 13:37:40 -04:00
Volodymyr Sapsai a28678e20a Revert "Reland "[Modules] Add stats to measure performance of building and loading modules.""
This reverts commit 4000c9ee18.

Test "LLVM :: Other/statistic.ll" is failing on Windows.
2020-10-19 18:27:30 -07:00
Volodymyr Sapsai 4000c9ee18 Reland "[Modules] Add stats to measure performance of building and loading modules."
Measure amount of high-level or fixed-cost operations performed during
building/loading modules and during header search. High-level operations
like building a module or processing a .pcm file are motivated by
previous issues where clang was re-building modules or re-reading .pcm
files unnecessarily. Fixed-cost operations like `stat` calls are tracked
because clang cannot change how long each operation takes but it can
perform fewer of such operations to improve the compile time.

Also tracking such stats over time can help us detect compile-time
regressions. Added stats are more stable than the actual measured
compilation time, so expect the detected regressions to be less noisy.

On relanding drop stats in MemoryBuffer.cpp as their value is pretty low
but affects a lot of clients and many of those aren't interested in
modules and header search.

rdar://problem/55715134

Reviewed By: aprantl, bruno

Differential Revision: https://reviews.llvm.org/D86895
2020-10-19 15:44:11 -07:00
Volodymyr Sapsai 9eba6b20a0 Revert "[Modules] Add stats to measure performance of building and loading modules."
This reverts commit c4bacc3c9b.

Test "LLVM :: ThinLTO/X86/funcimport-stats.ll" is failing. Reverting now
and will recommit after making the test not fail with the added stats.
2020-09-24 12:36:06 -07:00
Volodymyr Sapsai c4bacc3c9b [Modules] Add stats to measure performance of building and loading modules.
Measure amount of high-level or fixed-cost operations performed during
building/loading modules and during header search. High-level operations
like building a module or processing a .pcm file are motivated by
previous issues where clang was re-building modules or re-reading .pcm
files unnecessarily. Fixed-cost operations like `stat` calls are tracked
because clang cannot change how long each operation takes but it can
perform fewer of such operations to improve the compile time.

Also tracking such stats over time can help us detect compile-time
regressions. Added stats are more stable than the actual measured
compilation time, so expect the detected regressions to be less noisy.

rdar://problem/55715134

Reviewed By: aprantl, bruno

Differential Revision: https://reviews.llvm.org/D86895
2020-09-24 12:23:47 -07:00
Alexandre Ganea f5314d15af [Support] On Unix, let the CrashRecoveryContext return the signal code
Before this patch, the CrashRecoveryContext was returning -2 upon a signal, like ExecuteAndWait does. This didn't match the behavior on Windows, where the the exception code was returned.

We now return the signal's code, which optionally allows for re-throwing the signal later. Doing so requires all custom handlers to be removed first, through llvm::sys::unregisterHandlers() which we made a public API.

This is part of https://reviews.llvm.org/D70378
2020-09-24 08:21:43 -04:00
Aleksandr Platonov ceffd6993c [Support][Windows] Fix incorrect GetFinalPathNameByHandleW() return value check in realPathFromHandle()
`GetFinalPathNameByHandleW(,,N,)` returns:
- `< N` on success (this value does not include the size of the terminating null character)
- `>= N` if buffer is too small (this value includes the size of the terminating null character)

So, when `N == Buffer.capacity() - 1`, we need to resize buffer if return value is > `Buffer.capacity() - 2`.
Also, we can set `N` to `Buffer.capacity()`.

Thus, without this patch `realPathFromHandle()` returns unfilled buffer when length of the final path of the file is equal to `Buffer.capacity()` or `Buffer.capacity() - 1`.

Reviewed By: andrewng, amccarth

Differential Revision: https://reviews.llvm.org/D86564
2020-08-26 22:11:44 +03:00
Dibya Ranjan Mishra a7da7e421c [Support] Allow printing the stack trace only for a given depth
Differential Revision: https://reviews.llvm.org/D85458
2020-08-26 09:27:42 -04:00
Arthur Eubanks 2b5502c350 [NFC] Use value initializer for OVERLAPPED
To fix
../llvm/lib/Support/Windows/Path.inc(1265,21): warning: missing field
'InternalHigh' initializer [-Wmissing-field-initializers]
  OVERLAPPED OV = {0};

Differential Revision: https://reviews.llvm.org/D85480
2020-08-07 11:18:33 -07:00
Serge Pavlov 536736995b [Support] Add file lock/unlock functions
This is recommit of f51bc4fb60, reverted in 8577595e03, because
the function `flock` is not available on Solaris. In this variant
`flock` was replaced with `fcntl`, which is a POSIX function.

New functions `lockFile`, `tryLockFile` and `unlockFile` implement
simple file locking. They lock or unlock entire file. This must be
enough to support simulataneous writes to log files in parallel builds.

Differential Revision: https://reviews.llvm.org/D78896
2020-07-28 16:44:23 +07:00
Serge Pavlov dab898f9ab [Windows] Fix limit on command line size
This reapplies commit d4020ef7c4, reverted in ac0edc5588 because it
broke build of LLDB. This commit contains appropriate changes for LLDB.
The original commit message is below.

Documentation on CreateProcessW states that maximal size of command line
is 32767 characters including ternimation null character. In the
function llvm::sys::commandLineFitsWithinSystemLimits this limit was set
to 32768. As a result if command line was exactly 32768 characters long,
a response file was not created and CreateProcessW was called with
too long command line.

Differential Revision: https://reviews.llvm.org/D83772
2020-07-23 11:39:42 +07:00
Serge Pavlov ac0edc5588 Revert "[Windows] Fix limit on command line size"
This reverts commit d4020ef7c4. It broke
LLDB buildbot: http://lab.llvm.org:8011/builders/lldb-x64-windows-ninja/builds/17702.
2020-07-22 01:00:32 +07:00
Serge Pavlov d4020ef7c4 [Windows] Fix limit on command line size
Documentation on CreateProcessW states that maximal size of command line
is 32767 characters including ternimation null character. In the
function llvm::sys::commandLineFitsWithinSystemLimits this limit was set
to 32768. As a result if command line was exactly 32768 characters long,
a response file was not created and CreateProcessW was called with
too long command line.

Differential Revision: https://reviews.llvm.org/D83772
2020-07-21 17:33:22 +07:00
Andrew Ng f6eb5daa16 [Support] Fix Windows directory_iterator_construct out of bounds
Fix incorrect use of the size of Path when accessing PathUTF16, as the
UTF-16 path can be shorter. Added unit test for coverage of this test
case.

Thanks to Ding Fei (danix800) for the code fix, see
https://reviews.llvm.org/D83321.

Differential Revision: https://reviews.llvm.org/D83689
2020-07-15 10:13:45 +01:00
Sam McCall cd209f1a37 [Support] Add path::user_config_directory for $XDG_CONFIG_HOME etc
Reviewers: hokein

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83128
2020-07-06 12:20:55 +02:00
Ben Dunbobbin a27478e54f [Support][Windows] Prevent 2s delay when renaming a file that does not exist
Differential Revision: https://reviews.llvm.org/D82542
2020-07-02 10:41:17 +01:00
Martin Storsjö cdbd299800 [Support] Fix building for mingw on a case sensitive file system
This fixes cross building on a case sensitive file system after
2e613d2ded. (The official Windows
SDKs don't have self-consistent casing and can't be used as such on
case sentisive file systems without case fixups, while mingw headers
consistently use lower case.)
2020-06-20 00:39:22 +03:00
Serge Pavlov 2e613d2ded [Support] Get process statistics in ExecuteAndWait and Wait
The functions sys::ExcecuteAndWait and sys::Wait now have additional
argument of type pointer to structure, which is filled with process
execution statistics upon process termination. These are total and user
execution times and peak memory consumption. By default this argument is
nullptr so existing users of these function must not change behavior.

Differential Revision: https://reviews.llvm.org/D78901
2020-06-17 13:39:59 +07:00
Serge Pavlov 8577595e03 Revert "[Support] Add file lock/unlock functions"
This reverts commit f51bc4fb60.
It broke the Solaris buildbots (Builder clang-solaris11-sparcv9 Build #5494
<http://lab.llvm.org:8014/builders/clang-solaris11-sparcv9/builds/54).
2020-06-03 15:40:12 +07:00
Serge Pavlov f51bc4fb60 [Support] Add file lock/unlock functions
New functions `lockFile`, `tryLockFile` and `unlockFile` implement
simple file locking. They lock or unlock entire file. This must be
enough to support simulataneous writes to log files in parallel builds.

Differential Revision: https://reviews.llvm.org/D78896
2020-06-03 12:22:45 +07:00
James Henderson 79e5ecfa7a On Windows, handle interrupt signals without crash message
For LLVM on *nix systems, the signal handlers are not run on signals
such as SIGINT due to CTRL-C. See sys::CleanupOnSignal. This makes
sense, as such signals are not really crashes. Prior to this change,
this wasn't the case on Windows, however. This patch changes the Windows
behaviour to be consistent with Linux, and adds testing that verifies
this.

The test uses llvm-symbolizer, but any tool with an interactive mode
would do the job.

Fixes https://bugs.llvm.org/show_bug.cgi?id=45754.

Reviewed by: MaskRay, rnk, aganea

Differential Revision: https://reviews.llvm.org/D79847
2020-05-21 13:27:10 +01:00
Reid Kleckner 75cbf6dc5c Re-land "Optimize path::remove_dots"
This reverts commit fb5fd74685.
Re-instates commit 53913a65b4

The fix is to trim off trailing separators, as in `/foo/bar/` and
produce `/foo/bar`. VFS tests rely on this. I added unit tests for
remove_dots.
2020-05-04 16:40:39 -07:00
Nico Weber fb5fd74685 Revert "Optimize path::remove_dots"
This reverts commit 53913a65b4.
Breaks VFSFromYAMLTest.DirectoryIterationSameDirMultipleEntries
in SupportTests on non-Windows.
2020-05-03 12:46:46 -04:00
Reid Kleckner 53913a65b4 Optimize path::remove_dots
LLD calls this on every source file string in every object file when
writing PDBs, so it is somewhat hot.

Avoid rewriting paths that do not contain path traversal components
(./..). Use find_first_not_of(separators) directly instead of using the
path iterators. The path component iterators appear to be slow, and
directly searching for slashes makes it easier to find double separators
that need to be canonicalized.

I discovered that the VFS relies on remote_dots to not canonicalize
early slashes (/foo or C:/foo) on Windows, so I had to leave that
behavior behind with unit tests for it. This is undesirable, but I claim
that my change is NFC.
2020-05-03 07:58:05 -07:00
Sam McCall 4e769e93b9 Reland "Add a facility to get system cache directory and use it in clangd"
This reverts commit faf2dce1dd.
2020-04-29 00:56:36 +02:00
Eric Christopher faf2dce1dd Temporarily revert "Add a facility to get system cache directory and use it in clangd"
This reverts commit ad38f4b371.

As it broke building the unittests:

.../sources/llvm-project/llvm/unittests/Support/Path.cpp:334:5: error: use of undeclared identifier 'set'
    set(Value);
    ^
1 error generated.
2020-04-28 15:49:46 -07:00
Vojtěch Štěpančík ad38f4b371 Add a facility to get system cache directory and use it in clangd
Summary:
This patch adds a function that is similar to `llvm::sys::path::home_directory`, but provides access to the system cache directory.

For Windows, that is %LOCALAPPDATA%, and applications should put their files under %LOCALAPPDATA%\Organization\Product\.

For *nixes, it adheres to the XDG Base Directory Specification, so it first looks at the XDG_CACHE_HOME environment variable and falls back to ~/.cache/.

Subsequently, the Clangd Index storage leverages this new API to put index files somewhere else than the users home directory.

Fixes https://github.com/clangd/clangd/issues/341

Reviewers: sammccall, chandlerc, Bigcheese

Reviewed By: sammccall

Subscribers: hiraditya, ilya-biryukov, MaskRay, jkorous, dexonsmith, arphaman, kadircet, ormris, usaxena95, cfe-commits, llvm-commits

Tags: #clang-tools-extra, #clang, #llvm

Differential Revision: https://reviews.llvm.org/D78501
2020-04-28 23:18:31 +02:00
Sergej Jaskiewicz 5cef31074f Introduce llvm::sys::Process::getProcessId() and adopt it
Differential Revision: https://reviews.llvm.org/D78022
2020-04-16 15:05:37 +03:00
Simon Tatham aab9e9de4d [Support,Windows] Tolerate failure of CryptGenRandom
Summary:
In `Unix/Process.inc`, we seed a random number generator from
`/dev/urandom` if possible, but if not, we're happy to fall back to
ordinary pseudorandom strategies, like the current time and PID.

The corresponding function on Windows calls `CryptGenRandom`, but it
//doesn't// have a fallback if that strategy fails. But `CryptGenRandom`
//can// fail, if a cryptography provider isn't properly initialized, or
occasionally (by our observation) simply intermittently.

If it's reasonable on Unix to implement traditional pseudorandom-number
seeding as a fallback, then it's surely reasonable to do the same on
Windows. So this patch adds a last-ditch use of ordinary rand(), using
much the same strategy as the Unix fallback code.

Reviewers: hans, sammccall

Reviewed By: hans

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D77553
2020-04-07 09:18:12 +01:00
Alexandre Ganea 09158252f7 [ThinLTO] Allow usage of all hardware threads in the system
Before this patch, it wasn't possible to extend the ThinLTO threads to all SMT/CMT threads in the system. Only one thread per core was allowed, instructed by usage of llvm::heavyweight_hardware_concurrency() in the ThinLTO code. Any number passed to the LLD flag /opt:lldltojobs=..., or any other ThinLTO-specific flag, was previously interpreted in the context of llvm::heavyweight_hardware_concurrency(), which means SMT disabled.

One can now say in LLD:
/opt:lldltojobs=0 -- Use one std::thread / hardware core in the system (no SMT). Default value if flag not specified.
/opt:lldltojobs=N -- Limit usage to N threads, regardless of usage of heavyweight_hardware_concurrency().
/opt:lldltojobs=all -- Use all hardware threads in the system. Equivalent to /opt:lldltojobs=$(nproc) on Linux and /opt:lldltojobs=%NUMBER_OF_PROCESSORS% on Windows. When an affinity mask is set for the process, threads will be created only for the cores selected by the mask.

When N > number-of-hardware-threads-in-the-system, the threads in the thread pool will be dispatched equally on all CPU sockets (tested only on Windows).
When N <= number-of-hardware-threads-on-a-CPU-socket, the threads will remain on the CPU socket where the process started (only on Windows).

Differential Revision: https://reviews.llvm.org/D75153
2020-03-27 10:20:58 -04:00
Andrew Ng 328b72dd82 [Support] Fix clang warning in widenPath NFC
Differential Revision: https://reviews.llvm.org/D76544
2020-03-23 18:59:55 +00:00
Andrew Ng e6f6c55121 [Support] Improve Windows widenPath and add support for long UNC paths
Check the path length limit against the length of the UTF-16 version of
the input rather than the UTF-8 equivalent, as the UTF-16 length may be
shorter. Move widenPath from the llvm::sys::path namespace in Path.h to
the llvm::sys::windows namespace in WindowsSupport.h. Only use the
reduced path length limit for create directory. Canonicalize using
sys::path::remove_dots().

Differential Revision: https://reviews.llvm.org/D75372
2020-03-19 13:00:21 +00:00
Hans Wennborg 01f9abbb50 llvm-ar: Fix MinGW compilation
llvm-ar is using CompareStringOrdinal which is available
only starting with Windows Vista (WINVER 0x600).

Fix this by hoising WindowsSupport.h, which sets _WIN32_WINNT
to 0x0601, up to llvm/include/llvm/Support and use it in llvm-ar.

Patch by Cristian Adam!

Differential revision: https://reviews.llvm.org/D74599
2020-02-28 09:59:24 +01:00
Alexandre Ganea 8404aeb56a [Support] On Windows, ensure hardware_concurrency() extends to all CPU sockets and all NUMA groups
The goal of this patch is to maximize CPU utilization on multi-socket or high core count systems, so that parallel computations such as LLD/ThinLTO can use all hardware threads in the system. Before this patch, on Windows, a maximum of 64 hardware threads could be used at most, in some cases dispatched only on one CPU socket.

== Background ==
Windows doesn't have a flat cpu_set_t like Linux. Instead, it projects hardware CPUs (or NUMA nodes) to applications through a concept of "processor groups". A "processor" is the smallest unit of execution on a CPU, that is, an hyper-thread if SMT is active; a core otherwise. There's a limit of 32-bit processors on older 32-bit versions of Windows, which later was raised to 64-processors with 64-bit versions of Windows. This limit comes from the affinity mask, which historically is represented by the sizeof(void*). Consequently, the concept of "processor groups" was introduced for dealing with systems with more than 64 hyper-threads.

By default, the Windows OS assigns only one "processor group" to each starting application, in a round-robin manner. If the application wants to use more processors, it needs to programmatically enable it, by assigning threads to other "processor groups". This also means that affinity cannot cross "processor group" boundaries; one can only specify a "preferred" group on start-up, but the application is free to allocate more groups if it wants to.

This creates a peculiar situation, where newer CPUs like the AMD EPYC 7702P (64-cores, 128-hyperthreads) are projected by the OS as two (2) "processor groups". This means that by default, an application can only use half of the cores. This situation could only get worse in the years to come, as dies with more cores will appear on the market.

== The problem ==
The heavyweight_hardware_concurrency() API was introduced so that only *one hardware thread per core* was used. Once that API returns, that original intention is lost, only the number of threads is retained. Consider a situation, on Windows, where the system has 2 CPU sockets, 18 cores each, each core having 2 hyper-threads, for a total of 72 hyper-threads. Both heavyweight_hardware_concurrency() and hardware_concurrency() currently return 36, because on Windows they are simply wrappers over std:🧵:hardware_concurrency() -- which can only return processors from the current "processor group".

== The changes in this patch ==
To solve this situation, we capture (and retain) the initial intention until the point of usage, through a new ThreadPoolStrategy class. The number of threads to use is deferred as late as possible, until the moment where the std::threads are created (ThreadPool in the case of ThinLTO).

When using hardware_concurrency(), setting ThreadCount to 0 now means to use all the possible hardware CPU (SMT) threads. Providing a ThreadCount above to the maximum number of threads will have no effect, the maximum will be used instead.
The heavyweight_hardware_concurrency() is similar to hardware_concurrency(), except that only one thread per hardware *core* will be used.

When LLVM_ENABLE_THREADS is OFF, the threading APIs will always return 1, to ensure any caller loops will be exercised at least once.

Differential Revision: https://reviews.llvm.org/D71775
2020-02-14 10:24:22 -05:00
Reid Kleckner b074acb82f [Support] Don't modify the current EH context during stack unwinding
Copy it instead. Otherwise, key registers (such as RBP) may get zeroed
out by the stack unwinder.

Fixes CrashRecoveryTest.DumpStackCleanup with MSVC in release builds.

Reviewed By: stella.stamenova

Differential Revision: https://reviews.llvm.org/D73809
2020-01-31 17:04:01 -08:00
Benjamin Kramer 159709f04f [Support] Fix implicit std::string conversions on Win32. 2020-01-29 00:02:26 +01:00
Alexandre Ganea a1f16998f3 [Support] Optionally call signal handlers when a function wrapped by the the CrashRecoveryContext fails
This patch allows for handling a failure inside a CrashRecoveryContext in the same way as the global exception/signal handler. A failure will have the same side-effect, such as cleanup of temporarty file, printing callstack, calling relevant signal handlers, and finally returning an exception code. This is an optional feature, disabled by default.
This is a support patch for D69825.

Differential Revision: https://reviews.llvm.org/D70568
2020-01-11 15:27:07 -05:00
Bruno Ricci 2fe45e029d
[Support][NFC] Make some helper functions "static" in Memory.inc 2020-01-09 17:46:21 +00:00