Commit Graph

1669 Commits

Author SHA1 Message Date
Nicolas Guillemot 7479a2e00b [Support] Add raw_ostream_iterator: ostream_iterator for raw_ostream
Adds a class `raw_ostream_iterator` that behaves like
std::ostream_iterator, but can be used with raw_ostream.
This is useful for using raw_ostream with std algorithms.

For example, it can be used to output std containers as follows:

```
std::vector<int> V = { 1, 2, 3 };
std::copy(V.begin(), V.end(), raw_ostream_iterator<int>(outs(), ", "));
// Output: "1, 2, 3, "
```

The API tries to follow std::ostream_iterator as closely as is
practically possible.

Reviewed By: dblaikie, mkitzan

Differential Revision: https://reviews.llvm.org/D78795
2021-03-04 11:12:48 -08:00
Xiangling Liao e9f9ec837d [CMake][AIX] Adjust plugin library extension used on AIX
As stated in the CMake manual, we are supposed to use MODULE rules to generate
plugin libraries:

"MODULE libraries are plugins that are not linked into other targets but may be
loaded dynamically at runtime using dlopen-like functionality"

Besides, LLVM's plugin infrastructure fits with the AIX treatment of .so
shared objects more than it fits with the AIX treatment of .a library archives
(which may contain shared objects).

Differential revision: https://reviews.llvm.org/D96282
2021-03-04 11:23:06 -05:00
Tim Northover 888c5c24ca AArch64: report fp16 arithmetic is present for apple-a11 CPU.
AArch64.td got it right, but the target-parser dropped it, leading to missing
feature flags in Clang.
2021-03-02 15:07:18 +00:00
serge-sans-paille ca0bb0e887 Make sure some types are indeed trivially_copyable per llvm::is_trivially_copyable
Test a few types used as llvm::SmallVector parameter. It is important to ensure
we have a consistent behavior for these types to prevent ABI issues as the one
we met in https://bugs.llvm.org/show_bug.cgi?id=39427.

Differential Revision: https://reviews.llvm.org/D96536
2021-02-24 18:24:57 +01:00
Alexey Lapshin 875b3b2cdd [Support] Add reserve() method to the raw_ostream.
If resulting size of the output stream is already known,
then the space for stream data could be preliminary
allocated in some cases. f.e. raw_string_ostream could
preallocate the space for the target string(it allows
to avoid reallocations during writing into the stream).

Differential Revision: https://reviews.llvm.org/D91693
2021-02-23 14:06:38 +03:00
cynecx 656ead1fb7 [llvm/Support] Add SHA256 implementation
Adds an *unaudited* SHA-256 implementation to `llvm/Support`. The ongoing lld-macho effort needs this to emit an adhoc code signature for macho files on macOS Big Sur.

Reviewed By: mehdi_amini

Differential Revision: https://reviews.llvm.org/D96540
2021-02-14 19:01:01 +00:00
David Tenty 318ed90144 [AIX][llvm][support] Implement getHostCPUName
We implement getHostCPUName() for AIX via systemcfg interfaces since access to the processor version register is a privileged operation. We return a value based on the  current processor implementation mode.

This fixes the cpu detection used by clang for `-mcpu=native`.

Reviewed By: hubert.reinterpretcast

Differential Revision: https://reviews.llvm.org/D95966
2021-02-09 16:30:18 -05:00
Christopher Tetreault b8b054aa8a Reland "Ensure that InstructionCost actually implements a total ordering"
The operator< in the previous attempt was incorrect. It is unfortunate
that this was only caught by the expensive checks.

This reverts commit ff1147c363.
2021-02-04 10:04:10 -08:00
Joachim Meyer e3f02302e3 [Support] Indent multi-line descr of enum cli options.
As noted in https://reviews.llvm.org/D93459, the formatting of
multi-line descriptions of clEnumValN and the likes is unfavorable.
Thus this patch adds support for correctly indenting these.

Reviewed By: serge-sans-paille

Differential Revision: https://reviews.llvm.org/D93494
2021-02-04 10:14:44 +01:00
Richard Smith 32e98f05fe Diagnose if a SLEB128 is too large to fit in an int64_t.
Previously we'd hit UB due to an invalid left shift operand.

Also fix the WASM emitter to properly use SLEB128 encoding instead of
ULEB128 encoding for signed fields so that negative numbers don't
result in overly-large values that we can't read back any more.

In passing, don't diagnose a non-canonical ULEB128 that fits in a uint64_t but
has redundant trailing zero bytes.

Reviewed By: dblaikie, aardappel

Differential Revision: https://reviews.llvm.org/D95510
2021-02-02 14:33:34 -08:00
Christopher Tetreault ff1147c363 Revert "Ensure that InstructionCost actually implements a total ordering"
This reverts commit b481cd519e.
2021-02-02 12:10:02 -08:00
Christopher Tetreault b481cd519e Ensure that InstructionCost actually implements a total ordering
Previously, operator== would consider the actual equality of the pairs
(lhs.Value, lhs.State) == (rhs.Value, rhs.State). However, if an invalid
cost was involved in a call to operator<, only the state would be
compared. Thus, it was not the case that ({2, Invalid} < {3, Invalid} ||
{2, Invalid} > {3, Invalid} || {2, Invalid} == {3, Invalid}).

This patch implements a true total ordering, where cost state is
considered first, then value. While it's not really imporant that
{2, Invalid} be considered to be less than {3, Invalid}, it's not a
problem either. This patch also implements operator== in terms of
operator<, so the two definitions will be kept in sync.

Reviewed By: sdesmalen

Differential Revision: https://reviews.llvm.org/D95803
2021-02-02 11:49:14 -08:00
Nathan Hawes ecb00a7762 [VFS] Add support to RedirectingFileSystem for mapping a virtual directory to one in the external FS.
Previously file entries in the -ivfsoverlay yaml could map to a file in the
external file system, but directories had to list their contents in the form of
other file entries or directories. Allowing directory entries to map to a
directory in the external file system makes it possible to present an external
directory's contents in a different location and (in combination with the
'fallthrough' option) overlay one directory's contents on top of another.

rdar://problem/72485443
Differential Revision: https://reviews.llvm.org/D94844
2021-02-02 14:56:17 +10:00
Duncan P. N. Exon Smith 080952a944 Support: Remove duplicated code in {File,clang::ModulesDependency}Collector, NFC
Refactor the duplicated canonicalize-path logic in `FileCollector` and
`ModulesDependencyCollector` into a new utility called
`PathCanonicalizer` that's shared. This popped up when tracking down a
bug common to both in https://reviews.llvm.org/D95202.

As drive-bys, update a few names and comments to better reflect the
effect of the code, delay removal of `..`s to avoid an unnecessary extra
string copy, and leave behind a couple of FIXMEs for future
consideration.

Differential Revision: https://reviews.llvm.org/D95279
2021-01-25 15:09:00 -08:00
Jonas Devlieghere f50b8ee71f [YAML I/O] Fix bug in emission of empty sequence
Don't emit an output dash for an empty sequence. Take emitting a vector
of strings for example:

  std::vector<std::string> Strings = {"foo", "bar"};
  LLVM_YAML_IS_SEQUENCE_VECTOR(std::string)
  yout << Strings;

This emits the following YAML document.

  ---
  - foo
  - bar
  ...

When the vector is empty, this generates the following result:

  ---
  - []
  ...

Although this is valid YAML, it does not match what we meant to emit.
The result is a one-element sequence consisting of an empty list.
Indeed, if we were to try to read this again we get an error:

  YAML:2:4: error: not a mapping
  - []

The problem is the output dash before the empty list. The correct output
would be:

  ---
  []
  ...

This patch fixes that by not emitting the output dash for an empty
sequence.

Differential revision: https://reviews.llvm.org/D95280
2021-01-25 13:35:36 -08:00
Paul Robinson 6ea7ecbb72 [RGT] Don't use EXPECT* macros in a subprocess that exits by signalling
Found by the Rotten Green Tests project.

Differential Revision: https://reviews.llvm.org/D95256
2021-01-22 15:04:34 -08:00
Jonas Devlieghere 0be9ca7c0f [VFS] Fix inconsistencies between relative paths and fallthrough.
This patch addresses inconsistencies in the way fallthrough is handled
in the RedirectingFileSystem. Rather than trying to change the working
directory of the external filesystem, the RedirectingFileSystem will
canonicalize every path before handing it down. This guarantees that
relative paths are resolved relative to the RedirectingFileSystem's
working directory.

This allows us to have a strictly virtual working directory, and still
fallthrough for absolute paths, but not for relative paths that would
get resolved incorrectly at the lower layer (for example, in case of the
RealFileSystem, because the strictly virtual path does not exist).

Differential revision: https://reviews.llvm.org/D95188
2021-01-22 14:15:48 -08:00
Ryan Houdek 045d84f4e6 D94954: Fixes Snapdragon Kryo CPU core detection
All of these families were claiming to be a73 based, which was causing
-mcpu/mtune=native to never use the newer features available to these
cores.

Goes through each and bumps the individual cores to their respective Big
counterparts. Since this code path doesn't support big.little detection,
there was already a precedent set with the Qualcomm line to choose the
big cores only.

Adds a comment on each line for the product's name that the part number
refers to. Confirmed on-device and through Linux header naming
convections.

Additionally newer SoCs mix CPU implementer parts from multiple
implementers. Both 0x41 (ARM) and 0x51 (Qualcomm) in the Snapdragon case

This was causing a desync in information where the scan at the start to
find the implementer would mismatch the part scan later on.
Now scan for both implementer and part at the start so these stay in
sync.

Differential Revision: https://reviews.llvm.org/D94954
2021-01-20 22:23:43 +00:00
Tim Northover 6259fbd8b6 AArch64: add apple-a14 as a CPU
This CPU supports all v8.5a features except BTI, and so identifies as v8.5a to
Clang. A bit weird, but the best way for things like xnu to detect the new
features it cares about.
2021-01-19 14:04:53 +00:00
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
Simon Pilgrim 0b46f19a9e [Support] Ensure KnownBits::sextInReg can handle the src == dst sext-in-reg case.
This was resulting in assertions inside APInt::zext that we were extending to the same bitwidth.
2021-01-14 14:50:21 +00:00
Simon Pilgrim e8622d27c0 [Support] Add KnownBits::sextInReg exhaustive tests
Requested by @foad in rG9cf4f493a72f
2021-01-14 14:27:45 +00:00
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
David Sherwood b7ccaca537 [NFC] Remove min/max functions from InstructionCost
Removed the InstructionCost::min/max functions because it's
fine to use std::min/max instead.

Differential Revision: https://reviews.llvm.org/D94301
2021-01-11 09:00:12 +00:00
Mark Murray 7d4a8bc417 [AArch64] Add +flagm archictecture option, allowing the v8.4a flag modification extension.
Differential Revision: https://reviews.llvm.org/D94081
2021-01-08 13:21:12 +00:00
Mark Murray af7cce2fa4 [AArch64] Add +pauth archictecture option, allowing the v8.3a pointer authentication extension.
Differential Revision: https://reviews.llvm.org/D94083
2021-01-08 13:21:11 +00:00
David Blaikie 3503c85681 Fixup Asserts+!AbiBreakingChecks fallout from db33f85c71 2021-01-07 14:18:19 -08:00
Amara Emerson a1265690cf Fix failing triple test for macOS 11 with non-zero minor versions.
Differential Revision: https://reviews.llvm.org/D94197
2021-01-06 14:57:37 -08:00
Reid Kleckner f4bcbdf9ce Suppress GCC Wdangling-else warning on gtest macros
See https://github.com/google/googletest/issues/1119
2021-01-05 17:32:56 -08:00
Simon Pilgrim 23b4198652 [Support] Add KnownBits::icmp helpers.
Check if all possible values for a pair of knownbits give the same icmp result - these are based off the checks performed in InstCombineCompares.cpp and D86578.

Add exhaustive unit test coverage - a followup will update InstCombineCompares.cpp to use this.
2021-01-04 12:46:27 +00:00
Mark Murray 5abfeccf10 [ARM][AArch64] Add Cortex-A78C Support for Clang and LLVM
This patch upstreams support for the Armv8-a Cortex-A78C
processor for AArch64 and ARM.

In detail:

Adding cortex-a78c as cpu option for aarch64 and arm targets in clang
Adding Cortex-A78C CPU name and ProcessorModel in llvm
Details of the CPU can be found here:
https://www.arm.com/products/silicon-ip-cpu/cortex-a/cortex-a78c
2020-12-29 10:18:59 +00:00
Simon Pilgrim 6895581fd2 [Support] Add KnownBits::getSignedMinValue/getSignedMaxValue helpers.
Add unit test coverage - a followup will update InstCombineCompares.cpp to use this and could be used by D86578 as well.
2020-12-24 14:10:12 +00:00
David Spickett 781a816d4c [llvm][Arm/AArch64] Format extension flags in CPU test failures
Previously you just two hex numbers you had to decode manually.
This change adds a predicate formatter for extension flags
to produce failure messages like:
```
[ RUN      ] AArch64CPUTests/AArch64CPUTestFixture.testAArch64CPU/2
<...>llvm/unittests/Support/TargetParserTest.cpp:862:
Failure
Expected extension flags: +fp-armv8, +crc, +crypto (0xe)
     Got extension flags: +fp-armv8, +neon, +crc, +crypto (0x1e)
[  FAILED  ] AArch64CPUTests/AArch64CPUTestFixture.testAArch64CPU/2,
where GetParam() = "cortex-a34", "armv8-a", <...>
```

From there you can take the feature name and map it back
to the enum in ARM/AArch64TargetParser.def.
(which isn't perfect but you've probably got both files
open if you're editing these tests)

Note that AEK_NONE is not meant to be user facing in the compiler
but here it is part of the tests. So failures may show an
extension "none" where the normal target parser wouldn't.

The formatter is implemented as a template on ARM::ISAKind
because the predicate formatters assume all parameters are used
for comparison.
(e.g. PRED_FORMAT3 is for comparing 3 values, not having 3
arguments in general)

Reviewed By: MarkMurrayARM

Differential Revision: https://reviews.llvm.org/D93448
2020-12-22 11:13:36 +00:00
David Spickett a6783cd7b6 [llvm][ARM/AArch64] Convert Target Parser CPU tests to fixtures
Also convert the test function to use EXPECT_EQ and
remove the special case for the AEK_NONE extension.

This means that each test is marked as failing separatley
and the accumultated EXPECT failures are printed next
to that test, with its parameters.

Before they would be hidden by the "pass &=" pattern
and failures would print in one block since it was a
"single" test.

Example of the new failure messages:
```
ARMCPUTestsPart1/ARMCPUTestFixture.ARMCPUTests/6
[==========] Running 1 test from 1 test case.
[----------] Global test environment set-up.
[----------] 1 test from ARMCPUTestsPart1/ARMCPUTestFixture
[ RUN      ] ARMCPUTestsPart1/ARMCPUTestFixture.ARMCPUTests/6
/work/open_source/nightly-llvm/llvm-project/llvm/unittests/Support/TargetParserTest.cpp:66:
Failure
      Expected: params.ExpectedFlags
      Which is: 3405705229
To be equal to: default_extensions
      Which is: 1
[  FAILED  ] ARMCPUTestsPart1/ARMCPUTestFixture.ARMCPUTests/6, where
GetParam() = "arm8", "armv4", "none", 0xcafef00d, "4" (0 ms)
```

Reviewed By: MarkMurrayARM

Differential Revision: https://reviews.llvm.org/D93392
2020-12-22 09:07:20 +00:00
Lucas Prates c5046ebdf6 [ARM] Adding v8.7-A command-line support for the ARM target
This extends the command-line support for the 'armv8.7-a' architecture
name to the ARM target.

Based on a patch written by Momchil Velikov.

Reviewed By: ostannard

Differential Revision: https://reviews.llvm.org/D93231
2020-12-17 13:48:54 +00:00
Lucas Prates c4d851b079 [ARM][AAarch64] Initial command-line support for v8.7-A
This introduces command-line support for the 'armv8.7-a' architecture name
(and an alias without the '-', as usual), and for the 'ls64' extension name.

Based on patches written by Simon Tatham.

Reviewed By: ostannard

Differential Revision: https://reviews.llvm.org/D91776
2020-12-17 13:47:28 +00:00
David Spickett 7f8779e4e6 [llvm][AArch64] Actually check expected FPU for CPUs
We were passing this as an argument but never using
it. ARM has always checked this.

Note that the FPU list is shared between ARM and AArch64
so there is no AArch64::getFPUName, just ARM::getFPUName.

Reviewed By: dmgreen

Differential Revision: https://reviews.llvm.org/D93387
2020-12-17 09:15:51 +00:00
Reid Kleckner d2ed9d6b7e Revert "ADT: Migrate users of AlignedCharArrayUnion to std::aligned_union_t, NFC"
We determined that the MSVC implementation of std::aligned* isn't suited
to our needs. It doesn't support 16 byte alignment or higher, and it
doesn't really guarantee 8 byte alignment. See
https://github.com/microsoft/STL/issues/1533

Also reverts "ADT: Change AlignedCharArrayUnion to an alias of std::aligned_union_t, NFC"

Also reverts "ADT: Remove AlignedCharArrayUnion, NFC" to bring back
AlignedCharArrayUnion.

This reverts commit 4d8bf870a8.

This reverts commit d10f9863a5.

This reverts commit 4b5dc150b9.
2020-12-14 17:04:06 -08:00
Nico Weber eaa0982334 [mac/arm] skip MappedMemoryTest that try to map w+x
macOS/arm is w^x, so these tests don't work. Fixes these failures:

  LLVM-Unit :: Support/./SupportTests/AllocationTests/MappedMemoryTest.AllocAndRelease/5
  LLVM-Unit :: Support/./SupportTests/AllocationTests/MappedMemoryTest.AllocAndReleaseHuge/5
  LLVM-Unit :: Support/./SupportTests/AllocationTests/MappedMemoryTest.BasicWrite/5
  LLVM-Unit :: Support/./SupportTests/AllocationTests/MappedMemoryTest.DuplicateNear/5
  LLVM-Unit :: Support/./SupportTests/AllocationTests/MappedMemoryTest.EnabledWrite/3
  LLVM-Unit :: Support/./SupportTests/AllocationTests/MappedMemoryTest.EnabledWrite/4
  LLVM-Unit :: Support/./SupportTests/AllocationTests/MappedMemoryTest.EnabledWrite/5
  LLVM-Unit :: Support/./SupportTests/AllocationTests/MappedMemoryTest.MultipleAllocAndRelease/5
  LLVM-Unit :: Support/./SupportTests/AllocationTests/MappedMemoryTest.MultipleWrite/5
  LLVM-Unit :: Support/./SupportTests/AllocationTests/MappedMemoryTest.SuccessiveNear/5
  LLVM-Unit :: Support/./SupportTests/AllocationTests/MappedMemoryTest.UnalignedNear/5
  LLVM-Unit :: Support/./SupportTests/AllocationTests/MappedMemoryTest.ZeroNear/5
  LLVM-Unit :: Support/./SupportTests/AllocationTests/MappedMemoryTest.ZeroSizeNear/5

Part of PR46647.
2020-12-12 19:46:32 -05:00
Nathan James 0e5bfffb13
[YAML] Support extended spellings when parsing bools.
Support all the spellings of boolean datatypes according to https://yaml.org/type/bool.html

Reviewed By: silvas

Differential Revision: https://reviews.llvm.org/D92755
2020-12-12 12:50:34 +00:00
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
Sjoerd Meijer 99ad078b91 [AArch64] Cortex-R82: remove crypto
Remove target features crypto for Cortex-R82, because it doesn't have any, and
add LSE which was missing while we are at it.
This also removes crypto from the v8-R architecture description because that
aligns better with GCC and so far none of the R-cores have implemented crypto,
so is probably a more sensible default.

Differential Revision: https://reviews.llvm.org/D91994
2020-12-10 12:54:51 +00:00
Duncan P. N. Exon Smith 75cd8d756d Support: Add RedirectingFileSystem::create from simple list of redirections
Add an overload of `RedirectingFileSystem::create` that builds a
redirecting filesystem off of a simple vector of string pairs. This is
intended to be used to support `clang::arcmt::FileRemapper` and
`clang::PreprocessorOptions::RemappedFiles`.

Differential Revision: https://reviews.llvm.org/D91317
2020-12-08 17:53:30 -08:00
Duncan P. N. Exon Smith a22eda548b VFS: Return new file systems as uniquely owned when possible, almost NFC
Uniformly return uniquely-owned filesystems from VFS creation APIs. The
one exception is `getRealFileSystem`, which has a single instance and
needs to be shared.

This is almost NFC, except that it fixes a memory leak in
`vfs::collectVFSFromYAML()`.

Depends on https://reviews.llvm.org/D92888

Differential Revision: https://reviews.llvm.org/D92890
2020-12-08 17:33:46 -08:00
Duncan P. N. Exon Smith 4d8bf870a8 ADT: Remove AlignedCharArrayUnion, NFC
Prep commit already migrated users over to std::aligned_union_t; this
just deletes the type / header / test.

Differential Revision: https://reviews.llvm.org/D92517
2020-12-04 14:13:22 -08:00
Duncan P. N. Exon Smith e763e032f8 Support: Change InMemoryFileSystem::addFileNoOwn to take a MemoryBufferRef, NFC
Found this by chance when looking at the InMemoryFileSystem API, seems
like an easy cleanup.

Differential Revision: https://reviews.llvm.org/D90893
2020-12-03 18:09:52 -08:00
Mehdi Amini 6cd9608fb3 Revert "Switch to std::is_trivially_move_constructible and std::is_trivially_copy_constructible"
This reverts commit c8d406c93c.

Builds are broken with some versions of GCC.
2020-12-03 19:58:06 +00:00
serge-sans-paille 9501419e87 Speedup some unicode rendering
Use a fast path for column width computation for ascii characters. Especially
relevant for llvm-objdump.

before:

    % time ./bin/llvm-objdump -D  -j .text /lib/libc.so.6 >/dev/null
    ./bin/llvm-objdump -D -j .text /lib/libc.so.6 > /dev/null  0.75s user 0.01s system 99% cpu 0.757 total

after:

    % time ./bin/llvm-objdump -D  -j .text /lib/libc.so.6 >/dev/null
    ./bin/llvm-objdump -D -j .text /lib/libc.so.6 > /dev/null  0.37s user 0.01s system 99% cpu 0.378 total

Differential Revision: https://reviews.llvm.org/D92180
2020-12-03 20:11:11 +01:00
Fangrui Song c8d406c93c Switch to std::is_trivially_move_constructible and std::is_trivially_copy_constructible
Differential Revision: https://reviews.llvm.org/D92543
2020-12-03 09:15:40 -08:00
Fangrui Song 1d6ebdfb66 Switch from llvm::is_trivially_copyable to std::is_trivially_copyable
GCC<5 did not support std::is_trivially_copyable. Now LLVM builds require 5.1
we can migrate to std::is_trivially_copyable.

The Optional.h change made MSVC choke
(https://buildkite.com/llvm-project/premerge-checks/builds/18587#cd1bb616-ffdc-4581-9795-b42c284196de)
so I leave it out for now.

Differential Revision: https://reviews.llvm.org/D92514
2020-12-02 22:02:48 -08:00
Reid Kleckner 91e66bfd32 Revert "Use std::is_trivially_copyable", breaks MSVC build
Revert "Delete llvm::is_trivially_copyable and CMake variable HAVE_STD_IS_TRIVIALLY_COPYABLE"

This reverts commit 4d4bd40b57.

This reverts commit 557b00e0af.
2020-12-02 14:30:46 -08:00
Fangrui Song 4d4bd40b57 Use std::is_trivially_copyable
GCC<5 did not support std::is_trivially_copyable. Now LLVM builds require 5.1
we can migrate to std::is_trivially_copyable.
2020-12-02 09:58:07 -08:00
LemonBoy f502b14d40 [ARMAttributeParser] Correctly parse and print Tag_THUMB_ISA_use=3
I took the "Permitted"/"Not Permitted" combo from the `Tag_ARM_ISA_use` case (GNU tools print "Yes").

Reviewed By: compnerd, MaskRay, simon_tatham

Differential Revision: https://reviews.llvm.org/D90305
2020-11-28 12:28:22 -08:00
Mark Murray 2b6691894a [ARM][AArch64] Adding Neoverse N2 CPU support
Add support for the Neoverse N2 CPU to the ARM and AArch64 backends.

Differential Revision: https://reviews.llvm.org/D91695
2020-11-25 11:42:54 +00:00
Scott Linder 2980933d85 [YAMLIO] Support non-null-terminated inputs
In some places the parser guards against dereferencing `End`, while in
others it relies on the presence of a trailing `'\0'` to elide checks.

Add the remaining guards needed to ensure the parser never attempts to
dereference `End`, making it safe to not require a null-terminated input
buffer.

Update the parser fuzzer harness so that it tests with buffers that are
guaranteed to be non-null-terminated, null-terminated, and 1-terminated,
additionally ensuring the result of the parse is the same in each case.

Some of the regression tests were written by inspection, and some are
cases caught by the fuzzer which required additional fixes in the
parser.

Differential Revision: https://reviews.llvm.org/D84050
2020-11-18 23:06:03 +00:00
Scott Linder b877c35d4b [YAMLIO] Correctly diagnose empty alias/anchor
The `Range` of an alias/anchor token includes the leading `&` or `*`,
but it is skipped while parsing the name. The check for an empty name
fails to account for the skipped leading character and so the error is
never hit.

Fix the off-by-one and add a couple regression tests.

Reviewed By: dexonsmith

Differential Revision: https://reviews.llvm.org/D91462
2020-11-16 18:45:05 +00:00
Nikita Popov 9a85643cd3 [KnownBits] Combine abs() implementations
ValueTracking was using a more powerful abs() implementation. Roll
it into KnownBits::abs(). Also add an exhaustive test for abs(),
in both the poisoning and non-poisoning variants.
2020-11-13 22:23:50 +01:00
Lucas Prates c2c2cc1360 [ARM][AArch64] Adding Neoverse V1 CPU support
Add support for the Neoverse V1 CPU to the ARM and AArch64 backends.

This is based on patches from Mark Murray and Victor Campos.

Reviewed By: dmgreen

Differential Revision: https://reviews.llvm.org/D90765
2020-11-09 13:15:40 +00:00
Sander de Smalen 5ee9ef8519 [TypeSize] Extend UnivariateLinearPolyBase with getWithIncrement/Decrement methods
This patch adds getWithIncrement/getWithDecrement methods to
ElementCount and TypeSize to allow:

  TypeSize::getFixed(8).getWithIncrement(8)     <=> TypeSize::getFixed(16)
  TypeSize::getFixed(16).getWithDecrement(8)    <=> TypeSize::getFixed(8)
  TypeSize::getScalable(8).getWithIncrement(8)  <=> TypeSize::getScalable(16)
  TypeSize::getScalable(16).getWithDecrement(8) <=> TypeSize::getScalable(8)

This patch implements parts of the POC in D90342.

Reviewed By: ctetreau, dmgreen

Differential Revision: https://reviews.llvm.org/D90713
2020-11-06 09:01:19 +00:00
Reid Kleckner f55247456e Fix bugs in EOL marking in command line tokenizers
Add unit tests for this behavior, since the integration test for
clang-cl did not catch these bugs.

Fixes PR47604

Differential Revision: https://reviews.llvm.org/D90866
2020-11-05 13:01:32 -08:00
Simon Pilgrim 6729b6de1f [KnownBits] Move ValueTracking SREM KnownBits handling to KnownBits::srem. NFCI.
Move the ValueTracking implementation to KnownBits, the SelectionDAG version is more limited so I'm intending to replace that as a separate commit.
2020-11-05 14:58:33 +00:00
Simon Pilgrim e237d56b43 [KnownBits] Move ValueTracking/SelectionDAG UREM KnownBits handling to KnownBits::urem. NFCI.
Both these have the same implementation - so move them to a single KnownBits copy.

GlobalISel will be able to use this as well with minimal effort.
2020-11-05 14:30:59 +00:00
Simon Pilgrim 32bee18b84 [KnownBits] Move ValueTracking/SelectionDAG UDIV KnownBits handling to KnownBits::udiv. NFCI.
Both these have the same implementation - so move them to a single KnownBits copy.

GlobalISel will be able to use this as well with minimal effort.
2020-11-05 13:42:42 +00:00
Simon Pilgrim 6c1a31858d [UnitTests] Add exhaustive tests for KnownBits shl/lshr/ashr
Thanks to @foad for the suggestion.
2020-11-05 10:13:16 +00:00
Hans Wennborg 1d3cd7172b Fix GCC error: specialization of 'template<class LeafTy> struct llvm::LinearPolyBaseTypeTraits' in different namespace 2020-11-03 16:55:32 +01:00
Sander de Smalen 1667d23e58 [NFCI] Add StackOffset class and base classes for ElementCount, TypeSize.
This patch adds a linear polynomial base class, called LinearPolyBase, which
serves as a base class for StackOffset. It tries to represent a linear
polynomial like:

  c0 * scale0 + c1 * scale1 + ... + cK * scaleK

where the scale is implicit, meaning that only the coefficients are
encoded.

This patch also adds a univariate linear polynomial, which serves as
a base class for ElementCount and TypeSize. This tries to represent a
linear polynomial where only one dimension can be set at any one time,
i.e. a TypeSize is either fixed-sized, or scalable-sized, but cannot be
a combination of the two.

  class LinearPolyBase
     ^
     |
     +---- class StackOffset  (dimensions = 2 (fixed/scalable), type = int64_t)

  class UnivariateLinearPolyBase
     |
     |
     +---- class LinearPolySize (dimensions = 2 (fixed/scalable))
                  ^
                  |
                  +-------- class ElementCount  (type = unsigned)
                  |
                  |
                  +-------- class TypeSize      (type = uint64_t)

Reviewed By: ctetreau, david-arm

Differential Revision: https://reviews.llvm.org/D88982
2020-11-03 09:41:39 +00:00
Reid Kleckner c0a922b3db Add parallelTransformReduce and parallelForEachError
parallelTransformReduce is modelled on the C++17 pstl API of
std::transform_reduce, except our wrappers do not use execution policy
parameters.

parallelForEachError allows loops that contain potentially failing
operations to propagate errors out of the loop. This was one of the
major challenges I encountered while parallelizing PDB type merging in
LLD. Parallelizing a loop with parallelForEachError is not behavior
preserving: the loop will no longer stop on the first error, it will
continue working and report all errors it encounters in a list.

I plan to use this to propagate errors out of LLD's
coff::TpiSource::remapTpiWithGHashes, which currently stores errors an
error in the TpiSource object.

Differential Revision: https://reviews.llvm.org/D90639
2020-11-02 16:50:14 -08:00
Duncan P. N. Exon Smith c17da8676a Support: Avoid std::tie in Support/FileSystem/UniqueID.h, NFC
Running `-fsyntax-only` on UniqueID.h is 2x faster with this patch
(which avoids calling `std::tie` for `operator<`).  Since the transitive
includers of this file will go up as `FileEntryRef` gets used in more
places, avoid that compile-time hit.  This is a follow-up to
23ed570af1 (suggested by Reid Kleckner).

Also drop the `<tuple>` include from FileSystem.h (which was vestigal
from before UniqueID.h was split out).

Differential Revision: https://reviews.llvm.org/D90471
2020-11-02 13:26:15 -05:00
Georgii Rymar 6487ffafd1 Reland "[yaml2obj][ELF] - Simplify the code that performs sections validation."
This reverts commit 1b589f4d4d and relands the D89463
with the fix: update `MappingTraits<FileFilter>::validate()` in ClangTidyOptions.cpp to
match the new signature (change the return type to "std::string" from "StringRef").

Original commit message:

This:

Changes the return type of MappingTraits<T>>::validate to std::string
instead of StringRef. It allows to create more complex error messages.

It introduces std::vector<std::pair<StringRef, bool>> getEntries():
a new virtual method of Section, which is the base class for all sections.
It returns names of special section specific keys (e.g. "Entries") and flags that says if them exist in a YAML.
The code in validate() uses this list of entries descriptions to generalize validation.
This approach was discussed in the D89039 thread.

Differential revision: https://reviews.llvm.org/D89463
2020-10-20 16:25:33 +03:00
Georgii Rymar 1b589f4d4d Revert "[yaml2obj][ELF] - Simplify the code that performs sections validation."
This reverts commit b9e2b59680.
2020-10-20 15:16:56 +03:00
Georgii Rymar b9e2b59680 [yaml2obj][ELF] - Simplify the code that performs sections validation.
This:
1) Changes the return type of `MappingTraits<T>>::validate` to `std::string`
instead of `StringRef`. It allows to create more complex error messages.

2) It introduces std::vector<std::pair<StringRef, bool>> getEntries():
a new virtual method of Section, which is the base class for all sections.
It returns names of special section specific keys (e.g. "Entries") and flags that
says if them exist in a YAML. The code in validate() uses this list of entries
descriptions to generalize validation.
This approach was discussed in the D89039 thread.

Differential revision: https://reviews.llvm.org/D89463
2020-10-20 11:28:23 +03:00
Hans Wennborg 95fb3542e8 Disable DynamicLibraryTests when using LLVM_INTEGRATED_CRT_ALLOC (PR47881) 2020-10-16 16:49:58 +02:00
Rainer Orth 3b956a58f3 Reland "[Support][unittests] Enforce alignment in ConvertUTFTest"
This relands commit 53b3873cf4.  The failure
of `ConvertUTFTest.UTF16WrappersForConvertUTF16ToUTF8String` detected the
first time is fixed.

Differential Revision: https://reviews.llvm.org/D88824
2020-10-14 12:02:27 +02:00
Duncan P. N. Exon Smith f2b7d9f7fa Support: Allow use of MemoryBufferRef with line_iterator
Split out from https://reviews.llvm.org/D66782, use `Optional<MemoryBufferRef>`
in `line_iterator` so you don't need access to a `MemoryBuffer*`.  Follow up
patches in `clang/` will leverage this.

Differential Revision: https://reviews.llvm.org/D89280
2020-10-13 16:43:49 -04:00
Duncan P. N. Exon Smith f087597124 Support: Add operator== for MemoryBufferRef and split out MemoryBufferRef.h
As preparation for changing `LineIterator` to work with `MemoryBufferRef`:

- Add an `operator==` that uses buffer pointer identity to ensure two buffers
  are equivalent.
- Split out `MemoryBufferRef.h`, to avoid polluting `LineIterator.h` includers
  with everything from `MemoryBuffer.h`. This also means moving the
  `MemoryBuffer` constructor to a source file.

Differential Revision: https://reviews.llvm.org/D89279
2020-10-13 16:42:24 -04:00
Sam McCall 31a575bbc0 [JSON] Add ObjectMapper::mapOptional to validate optional data.
Currently the idiom for mapping optional fields is:
  ObjectMapper O(Val, P);
  if (!O.map("required1", Out.R1) || !O.map("required2", Out.R2))
    return false;
  O.map("optional1", Out.O1); // ignore result
  return true;

If `optional1` is present but malformed, then we won't detect/report
that error. We may even leave `Out` in an incomplete state while returning true.
Instead, we'd often prefer to ignore `optional1` if it is absent, but otherwise
behave just like map().

Differential Revision: https://reviews.llvm.org/D89128
2020-10-12 12:48:08 +02:00
Quentin Colombet d421e0484a [KnownBits] Add a sextOrTrunc method
We already offer zextOrTrunc and it seems natural to offer the
same capability for sign extension.

This patch is a preparatory addition useful for future computeKnownBits
developments.

Differential Revision: https://reviews.llvm.org/D88937
2020-10-08 11:33:06 -07:00
Quentin Colombet 9431f8ad2e [KnownBits] Add a computeForMul method
This patch refactors the logic in ValueTracking.cpp so that
computeKnownBitsForMul now uses a helper function from KnownBits.

NFC

Differential Revision: https://reviews.llvm.org/D88935
2020-10-08 11:33:06 -07:00
Nico Weber a4961f0d8a Revert "[Support][unittests] Enforce alignment in ConvertUTFTest"
This reverts commit 53b3873cf4.
Seems to break SupportTests.exe's
ConvertUTFTest.UTF16WrappersForConvertUTF16ToUTF8String
on Windows.
2020-10-07 22:23:08 -04:00
Daniel Sanders 91a98ec11e [json] Provide a means to delegate writing a value to another API
(Based on D87170 by dsanders)

I recently had need to call out to an external API to emit a JSON object as part
of one an LLVM tool was emitting. However, our JSON support didn't provide a way
to delegate part of the JSON output to that API.

Add rawValueBegin() and rawValueEnd() to maintain and check the internal state
while something else is writing to the stream. It's the users responsibility to
ensure that the resulting JSON output is still valid.

Differential Revision: https://reviews.llvm.org/D88902
2020-10-07 18:31:45 +02:00
Rainer Orth 53b3873cf4 [Support][unittests] Enforce alignment in ConvertUTFTest
`LLVM-Unit :: Support/./SupportTests/ConvertUTFTest.ConvertUTF16LittleEndianToUTF8String`
`FAIL`s on Solaris/sparcv9:

In `llvm/lib/Support/ConvertUTFWrapper.cpp` (`convertUTF16ToUTF8String`)
the `SrcBytes` arg is reinterpreted/accessed as `UTF16` (`unsigned short`,
which requires 2-byte alignment on strict-alignment targets like Sparc)
without anything guaranteeing the alignment, so the access yields a
`SIGBUS`.

This patch avoids this by enforcing the required alignment in the callers.

Tested on `sparcv9-sun-solaris2.11`.

Differential Revision: https://reviews.llvm.org/D88824
2020-10-07 09:08:41 +02:00
Sjoerd Meijer 8825fec37e [AArch64] Add CPU Cortex-R82
This adds support for -mcpu=cortex-r82. Some more information about this
core can be found here:

https://www.arm.com/products/silicon-ip-cpu/cortex-r/cortex-r82

One note about the system register: that is a bit of a refactoring because of
small differences between v8.4-A AArch64 and v8-R AArch64.

This is based on patches from Mark Murray and Mikhail Maltsev.

Differential Revision: https://reviews.llvm.org/D88660
2020-10-02 12:47:23 +01:00
Mikhail Maltsev 07b7a24e3f [unittests] Preserve LD_LIBRARY_PATH in crash recovery test
We need to preserve the LD_LIBRARY_PATH environment variable when
spawning a child process (certain setups rely on non-standard paths
for e.g. libstdc++). In order to achieve this, set
LLVM_CRC_UNIXCRCRETURNCODE in the parent process instead of creating
the child's environment from scratch.

Reviewed By: aganea

Differential Revision: https://reviews.llvm.org/D88308
2020-09-28 17:46:03 +01:00
Alexandre Ganea a6a6ccfc4c Fix f5314d15af - [Support] On Unix, let the CrashRecoveryContext return the signal code
This was causing bots to fail: http://green.lab.llvm.org/green/job/clang-stage1-RA/14828/consoleFull#6384962949ba4694-19c4-4d7e-bec5-911270d8a58c
2020-09-24 09:07:22 -04:00
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
Alexandre Ganea 24f510570f [Support] On Windows, ensure abort() can be catched several times in a row with CrashRecoveryContext
Before this patch, the CrashRecoveryContext would only catch the first abort(). Any further calls to abort() inside subsquent CrashRecoveryContexts would not be catched. This is because the Windows CRT removes the abort() handler before calling it.

This is part of https://reviews.llvm.org/D70378
2020-09-24 08:21:42 -04:00
Mikael Holmen a1217620a8 [unittests] Use std::make_tuple to make some toolchains happy again
My toolchain stopped working (LLVM 8.0, libstdc++ 5.4.0) after 577adda:

06:25:37 ../unittests/Support/Path.cpp:91:7: error: chosen constructor is explicit in copy-initialization
06:25:37       {"", false, false},  {"/", true, true},      {"/foo", true, true},
06:25:37       ^~~~~~~~~~~~~~~~~~
06:25:37 /proj/flexasic/app/llvm/8.0/bin/../lib/gcc/x86_64-unknown-linux-gnu/5.4.0/../../../../include/c++/5.4.0/tuple:479:19: note: explicit constructor declared here
06:25:37         constexpr tuple(_UElements&&... __elements)
06:25:37                   ^

This commit adds explicit calls to std::make_tuple to work around
the problem.
2020-09-24 11:25:36 +02:00
Sam McCall fa69b60806 [JSON] Add error reporting to fromJSON and ObjectMapper
Translating between JSON objects and C++ strutctures is common.
From experience in clangd, fromJSON/ObjectMapper work well and save a lot of
code, but aren't adopted elsewhere at least partly due to total lack of error
reporting beyond "ok"/"bad".

The recently-added error model should be rich enough for most applications.
It requires tracking the path within the root object and reporting local
errors at appropriate places.
To do this, we exploit the fact that the call graph of recursive
parse functions mirror the structure of the JSON itself.
The current path is represented as a linked list of segments, each of which is
on the stack as a parameter. Concretely, fromJSON now looks like:
  bool fromJSON(const Value&, T&, Path);

Beyond the signature change, this is reasonably unobtrusive: building
the path segments is mostly handled by ObjectMapper and the vector<T> fromJSON.
However the root caller of fromJSON must now create a Root object to
store the errors, which is a little clunky.

I've added high-level parse<T>(StringRef) -> Expected<T>, but it's not
general enough to be the primary interface I think (at least, not usable in
clangd).

All existing users (mostly just clangd) are updated in this patch,
making this change backwards-compatible is a bit hairy.

Differential Revision: https://reviews.llvm.org/D88103
2020-09-24 01:20:09 +02:00
Sam McCall 38de1c33a8 [JSON] Display errors associated with Paths in context
When an error occurs processing a JSON object, seeing the actual
surrounding data helps. Dumping just the node where the problem
was identified can be too much or too little information.

printErrorContext() shows the error message in its context, as a comment.
JSON values along the path to the broken place are shown in some detail,
the rest of the document is elided. For example:

```
{
  "credentials": [
    {
      "username": /* error: expected string */ 42,
      "password": "secret"
    },
    { ... }
  ]
  "backups": { ... }
}
```

Differential Revision: https://reviews.llvm.org/D88103
2020-09-24 00:34:11 +02:00
Sam McCall 16619e7139 [JSON] Facility to track position within an object and report errors.
This error model should be rich enough for most applications. It comprises:

- a name for the root object, so the user knows what we're parsing
- a path from the root object to the JSON node most associated with the error
- a local error message

This can be presented as an llvm::Error e.g.
  "expected string at ConfigFile.credentials[0].username"

It's designed to be cheap: Paths are a linked list of lightweight
objects on the stack. No heap allocations unless errors are encountered.

A subsequent commit will make use of this in the JSON-to-object
translation facilities: fromJSON and ObjectMapper.
However it's independent of these and can be used for e.g. validation alone.

Another subsequent commit will support showing the error in its context
within the parsed value.

Differential Revision: https://reviews.llvm.org/D88103
2020-09-24 00:09:09 +02:00
Sam McCall 140b7b6f09 [JSON] Allow emitting comments in json::OStream
This isn't standard JSON, but is a popular extension.
It will be used to show errors in context, rendering pseudo-json for humans.

Differential Revision: https://reviews.llvm.org/D88103
2020-09-23 23:34:57 +02:00
Vinicius Tinti 577adda54f [Support/Path] Add path::is_absolute_gnu
Implements IS_ABSOLUTE_PATH from GNU tools.

C++17 is_absolute behavior is different the from the behavior defined by GNU
tools.

According to cppreference.com, C++17 states: "An absolute path is a path
that unambiguously identifies the location of a file without reference
to an additional starting location."

In other words, the rules are:
 1. POSIX style paths with nonempty root directory are absolute.
 2. Windows style paths with nonempty root name and root directory are
    absolute.
 3. No other paths are absolute.

GNU rules are:
 1. Paths starting with a path separator are absolute.
 2. Windows style paths are also absolute if they start with a character
    followed by ':'.
 3. No other paths are absolute.

On Windows style the path "C:\Users\Default" has "C:" as root name and "\"
as root directory.

Hence "C:" on Windows is absolute under GNU rules and not absolute under
C++17 because it has no root directory. Likewise "/" and "\" on Windows are
absolute under GNU and are not absolute under C++17 due to empty root name.

Related to PR46368.

Differential Revision: https://reviews.llvm.org/D87667
2020-09-23 18:01:32 +01:00
Jon Roelofs c145a1ca25 AArch64::ArchKind's underlying type is uint64_t 2020-09-17 12:13:57 -07:00
Andrew Ng 6040e2a6d9 [Support] Add GlobPattern::isTrivialMatchAll()
GlobPattern::isTrivialMatchAll() returns true for the GlobPattern "*"
which will match all inputs.

This can be used to avoid performing expensive preparation of the input
for match() when the result of the match will always be true.

Differential Revision: https://reviews.llvm.org/D87468
2020-09-16 10:26:11 +01:00
Jianzhou Zhao 19531a81f1 Add raw_fd_stream_test.cpp into CMakeLists.txt
Fixing 0ece51c60c
2020-09-12 07:48:12 +00:00
Jianzhou Zhao 0ece51c60c Add raw_fd_stream that supports reading/seeking/writing
This is used by https://reviews.llvm.org/D86905 to support bitcode
writer's incremental flush.
2020-09-12 07:34:19 +00:00
Lang Hames 54fcea86b1 Revert "[Support] Use unique_function rather than std::function for ThreadPool TaskTy."
This reverts commit d9c8b0256c.

Some MSVC std::packaged_task implementations are not compatible with move-only types.
This caused failures on some of the Windows builders (e.g.
http://lab.llvm.org:8011/builders/sanitizer-windows/builds/69412).

Reverting until I can come up with a workaround.
2020-09-10 11:53:09 -07:00
Lang Hames d9c8b0256c [Support] Use unique_function rather than std::function for ThreadPool TaskTy.
This will allow non-copyable function objects (e.g. lambdas that capture
unique_ptrs) to be used with ThreadPool.

Differential Revision: https://reviews.llvm.org/D87467
2020-09-10 10:46:46 -07:00
Sergej Jaskiewicz e7b40c5492 [llvm] [unittest] Allow getting a C string from the TempDir helper class
The TempDir.path() member function returns a StringRef. We've been
calling the data() method on that StringRef, which does not guarantee
to return a null-terminated string (required by chdir and other POSIX
functions).

Introduce the c_str() method in the TempDir class, which returns the
proper string without the need to create a copy of the path at use site.
2020-09-09 01:53:15 +03:00