Commit Graph

5453 Commits

Author SHA1 Message Date
Liu, Chen3 756f597841 [X86] Support Intel avxvnni
This patch mainly made the following changes:

1. Support AVX-VNNI instructions;
2. Introduce ExplicitVEXPrefix flag so that vpdpbusd/vpdpbusds/vpdpbusds/vpdpbusds instructions only use vex-encoding when user explicity add {vex} prefix.

Differential Revision: https://reviews.llvm.org/D89105
2020-10-31 12:39:51 +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
Simon Pilgrim 0d17dc2e75 [X86] Fix cpu name typos
As discussed on PR26418 rGea84dc9500df incorrectly set the knl cpuname to tremont (and missed out the tremont cpuname entirely).
2020-10-28 15:50:53 +00:00
Nicolai Hähnle e025d09b21 Revert multiple patches based on "Introduce CfgTraits abstraction"
These logically belong together since it's a base commit plus
followup fixes to less common build configurations.

The patches are:

Revert "CfgInterface: rename interface() to getInterface()"

This reverts commit a74fc48158.

Revert "Wrap CfgTraitsFor in namespace llvm to please GCC 5"

This reverts commit f2a06875b6.

Revert "Try to make GCC5 happy about the CfgTraits thing"

This reverts commit 03a5f7ce12.

Revert "Introduce CfgTraits abstraction"

This reverts commit c0cdd22c72.
2020-10-27 20:33:30 +01:00
Nicolai Hähnle ce6900c6cb Revert "DomTree: Extract (mostly) read-only logic into type-erased base classes"
This reverts commit 848a68a032.
2020-10-27 20:33:29 +01:00
Jonas Devlieghere c4ef3115b4 Fix calls to (p)read on macOS when size > INT32_MAX
On macOS, the read and pread syscalls return EINVAL when the number of
bytes to read exceeds INT32_MAX:

a449c6a3b8/bsd/kern/sys_generic.c (L355)

rdar://68751407

Differential revision: https://reviews.llvm.org/D90201
2020-10-26 20:51:44 -07:00
Benjamin Kramer 39a0d6889d [X86] Add a stub for Intel's alderlake.
No scheduling, no autodetection.
2020-10-24 19:01:22 +02:00
Benjamin Kramer bd2cf96c09 [X86] Add a stub for znver3 based on the little public information there is in AMD's manuals
No scheduling, no autodetection. Just enough so -march=znver3 works.
2020-10-24 19:01:22 +02:00
Tianqing Wang be39a6fe6f [X86] Add User Interrupts(UINTR) instructions
For more details about these instructions, please refer to the latest
ISE document:
https://software.intel.com/en-us/download/intel-architecture-instruction-set-extensions-programming-reference.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D89301
2020-10-22 17:33:07 +08:00
Kirill Bobyrev 96685faf6d
[llvm] Use early exits and get rid of if-return-else-return pattern; NFC
https://llvm.org/docs/CodingStandards.html#use-early-exits-and-continue-to-simplify-code

Reviewed By: kadircet

Differential Revision: https://reviews.llvm.org/D89857
2020-10-21 14:18:42 +02:00
Cyndy Ishida acb33cba6d [llvm] Fix ODRViolations for VersionTuple YAML specializations NFC
It appears for Swift there was confusing errors when trying to parse APINotes, when libAPINotes and libInterfaceStub are linked, they both export symbol
`__ZN4llvm4yaml7yamlizeINS_12VersionTupleEEENSt3__19enable_ifIXsr16has_ScalarTraitsIT_EE5valueEvE4typeERNS0_2IOERS5_bRNS0_12EmptyContextE`, and discovered
same symbol defined within llvm-ifs.

This consolidates the boilerplate into YAMLTraits and defers the specific validation in reading the whole input.
fixes: rdar://problem/70450563

Reviewed By: phosek, dblaikie

Differential Revision: https://reviews.llvm.org/D89764
2020-10-20 18:29:15 -07:00
Nicolai Hähnle 848a68a032 DomTree: Extract (mostly) read-only logic into type-erased base classes
Avoid having to instantiate and compile a subset of the dominator tree logic
separately for each node type. More importantly, this allows generic
algorithms to be built on top of dominator trees without writing them as
templates -- such algorithms can now use opaque CfgBlockRef and
CfgInterface instead.

A type-erased implementation of dominator trees could be written in
terms of CfgInterface as well, but doing so would change the current
trade-off: it would slightly reduce code size at the cost of a slight
runtime overhead.

This patch does not change the trade-off, as it only does type-erasure
where basic blocks can be treated in a fully opaque way, i.e. it only
moves methods that don't require iteration over CFG successors and
predecessors.

v5:
- rename generic_{begin,end,children} back without the generic_ prefix
  and refer explictly to base class methods in NewGVN, which wants to
  mutate the order of dominator tree node children directly

v6:
- style change: iDom -> idom; it's arguable whether this is really
  invalid, since it is actually standard camelCase, but clang-tidy
  complains about it so... *shrug*
- rename {to,from}Generic -> {wrap,unwrap}Ref

Change-Id: Ib860dc04cf8bb093d8ed00be7def40d662213672

Differential Revision: https://reviews.llvm.org/D83089
2020-10-20 19:53:07 +02:00
Nicolai Hähnle c0cdd22c72 Introduce CfgTraits abstraction
The CfgTraits abstraction simplfies writing algorithms that are
generic over the type of CFG, and enables writing such algorithms
as regular non-template code that operates on opaque references
to CFG blocks and values.

Implementations of CfgTraits provide operations on the concrete
CFG types, e.g. `IrCfgTraits::BlockRef` is `BasicBlock *`.

CfgInterface is an abstract base class which provides operations
on opaque types CfgBlockRef and CfgValueRef. Those opaque types
encapsulate a `void *`, but the meaning depends on the concrete
CFG type. For example, MachineCfgTraits -- for use with MachineIR
in SSA form -- encodes a Register inside CfgValueRef. Converting
between concrete references and opaque/generic ones is done by
CfgTraits::{fromGeneric,toGeneric}. Convenience methods
CfgTraits::{un}wrap{Iterator,Range} are available as well.

Writing algorithms in terms of CfgInterface adds some overhead
(virtual method calls, plus in same cases it removes the
opportunity to inline iterators), but can be much more convenient
since generic algorithms can be written as non-templates.

This patch adds implementations of CfgTraits for all CFGs on
which dominator trees are calculated, so that the dominator
tree can be ported to this machinery. Only IrCfgTraits (LLVM IR)
and MachineCfgTraits (Machine IR in SSA form) are complete, the
other implementations are limited to the absolute minimum
required to make the upcoming dominator tree changes work.

v5:
- fix MachineCfgTraits::blockdef_iterator and allow it to iterate over
  the instructions in a bundle
- use MachineBasicBlock::printName

v6:
- implement predecessors/successors for all CfgTraits implementations
- fix error in unwrapRange
- rename toGeneric/fromGeneric into wrapRef/unwrapRef to have naming
  that is consistent with {wrap,unwrap}{Iterator,Range}
- use getVRegDef instead of getUniqueVRegDef

v7:
- std::forward fix in wrapping_iterator
- fix typos

v8:
- cleanup operators on CfgOpaqueType
- address other review comments

Change-Id: Ia75f4f268fded33fca11218a7d578c9aec1f3f4d

Differential Revision: https://reviews.llvm.org/D83088
2020-10-20 13:50:52 +02:00
Jonas Devlieghere f44fb13025 [FileCollector] Move interface into FileCollectorBase (NFC)
For the reproducers in LLDB we want to switch to an "immediate mode"
FileCollector that writes every file encountered straight to disk so we
can generate the actual mapping out-of-process. This patch moves the
interface into a separate base class.

Differential revision: https://reviews.llvm.org/D89742
2020-10-19 21:37:20 -07:00
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
Lang Hames 19402ce79a [Support] Add a C-API function to create a StringError instance.
This will allow C API clients to return errors from callbacks. This
functionality will be used in upcoming Orc C-bindings functions.
2020-10-19 01:59:04 -07:00
Stanislav Mekhanoshin 874524ab88 [AMDGPU] Drop array size in AMDGCNGPUs and R600GPUs
Differential Revision: https://reviews.llvm.org/D89568
2020-10-16 12:37:22 -07:00
Kito Cheng cfa7094e49 [RISCV] Add -mtune support
- The goal of this patch is improve option compatible with RISCV-V GCC,
   -mcpu support on GCC side will sent patch in next few days.

 - -mtune only affect the pipeline model and non-arch/extension related
   target feature, e.g. instruction fusion; in td file it called
   TuneFeatures, which is introduced by X86 back-end[1].

 - -mtune accept all valid option for -mcpu and extra alias processor
   option, e.g. `generic`, `rocket` and `sifive-7-series`, the purpose is
   option compatible with RISCV-V GCC.

 - Processor alias for -mtune will resolve according the current target arch,
   rv32 or rv64, e.g. `rocket` will resolve to `rocket-rv32` or `rocket-rv64`.

 - Interaction between -mcpu and -mtune:
   * -mtune has higher priority than -mcpu for pipeline model and
     TuneFeatures.

[1] https://reviews.llvm.org/D85165

Reviewed By: luismarques

Differential Revision: https://reviews.llvm.org/D89025
2020-10-16 13:55:08 +08:00
Stanislav Mekhanoshin d1beb95d12 [AMDGPU] gfx1032 target
Differential Revision: https://reviews.llvm.org/D89487
2020-10-15 12:41:18 -07:00
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
Wang, Pengfei 412cdcf2ed [X86] Add HRESET instruction.
For more details about these instructions, please refer to the latest ISE document: https://software.intel.com/en-us/download/intel-architecture-instruction-set-extensions-programming-reference.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D89102
2020-10-13 08:47:26 +08:00
Fangrui Song 012dd42e02 [X86] Support -march=x86-64-v[234]
PR47686. These micro-architecture levels are defined in the x86-64 psABI:

https://gitlab.com/x86-psABIs/x86-64-ABI/-/commit/77566eb03bc6a326811cb7e9

GCC 11 will support these levels.

Note, -mtune=x86-64-v[234] are invalid and __builtin_cpu_is cannot be
used on them.

Reviewed By: craig.topper, RKSimon

Differential Revision: https://reviews.llvm.org/D89197
2020-10-12 10:29:46 -07:00
David Sherwood c5ba0d33cc [SVE] Make ElementCount and TypeSize use a new PolySize class
I have introduced a new template PolySize class, where the template
parameter determines the type of quantity, i.e. for an element
count this is just an unsigned value. The ElementCount class is
now just a simple derivation of PolySize<unsigned>, whereas TypeSize
is more complicated because it still needs to contain the uint64_t
cast operator, since there are still many places in the code that
rely upon this implicit cast. As such the class also still needs
some of it's own operators.

I've tried to minimise the amount of code in the base PolySize
class, which led to a couple of changes:

1. In some places we were relying on '==' operator comparisons
between ElementCounts and the scalar value 1. I didn't put this
operator in the new PolySize class, and thought it was actually
clearer to use the isScalar() function instead.
2. I removed the isByteSized function and replaced it with calls
to isKnownMultipleOf(8).

I've also renamed NextPowerOf2 to be coefficientNextPowerOf2 so
that it's more consistent with coefficientDivideBy.

Differential Revision: https://reviews.llvm.org/D88409
2020-10-12 08:23:38 +01:00
Fangrui Song a8682554c6 [X86] Delete redundant 'static' from namespace scope 'static constexpr'. NFC
This decreases 7 lines as the result of packing more bits on one line.
2020-10-10 14:05:49 -07:00
Tim Renouf 666ef0db20 [AMDGPU] Add gfx602, gfx705, gfx805 targets
At AMD, in an internal audit of our code, we found some corner cases
where we were not quite differentiating targets enough for some old
hardware. This commit is part of fixing that by adding three new
targets:

* The "Oland" and "Hainan" variants of gfx601 are now split out into
  gfx602. LLPC (in the GPUOpen driver) and other front-ends could use
  that to avoid using the shaderZExport workaround on gfx602.

* One variant of gfx703 is now split out into gfx705. LLPC and other
  front-ends could use that to avoid using the
  shaderSpiCsRegAllocFragmentation workaround on gfx705.

* The "TongaPro" variant of gfx802 is now split out into gfx805.
  TongaPro has a faster 64-bit shift than its former friends in gfx802,
  and a subtarget feature could be set up for that to take advantage of
  it. This commit does not make that change; it just adds the target.

V2: Add clang changes. Put TargetParser list in order.
V3: AMDGCNGPUs table in TargetParser.cpp needs to be in GPUKind order,
    so fix the GPUKind order.

Differential Revision: https://reviews.llvm.org/D88916

Change-Id: Ia901a7157eb2f73ccd9f25dbacec38427312377d
2020-10-10 17:22:22 +01:00
Bevin Hansson dd3014f3dc [Fixed Point] Add floating point methods to APFixedPoint.
This adds methods to APFixedPoint for converting to and from
floating point values.

Differential Revision: https://reviews.llvm.org/D85961
2020-10-09 10:27:42 +02:00
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
Paul C. Anagnostopoulos 0c1bb4f885 [TableGen] New backend to print detailed records.
Pertinent lints are fixed.
2020-10-02 10:22:13 -04:00
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
Sanjay Patel 149f5b573c [APFloat] convert SNaN to QNaN in convert() and raise Invalid signal
This is an alternate fix (see D87835) for a bug where a NaN constant
gets wrongly transformed into Infinity via truncation.
In this patch, we uniformly convert any SNaN to QNaN while raising
'invalid op'.
But we don't have a way to directly specify a 32-bit SNaN value in LLVM IR,
so those are always encoded/decoded by calling convert from/to 64-bit hex.

See D88664 for a clang fix needed to allow this change.

Differential Revision: https://reviews.llvm.org/D88238
2020-10-01 14:37:38 -04:00
Craig Topper 12bdd427b3 [APFloat] Improve asserts in isSignificandAllOnes and isSignificandAllZeros so they protect shift operations from undefined behavior.
For example, the assert in isSignificandAllZeros allowed NumHighBits
to be integerPartWidth. But since it is used directly as a shift amount
it must be less than integerPartWidth.
2020-09-30 19:32:34 -07:00
Craig Topper b23916504a Patch IEEEFloat::isSignificandAllZeros and IEEEFloat::isSignificandAllOnes (bug 34579)
Patch IEEEFloat::isSignificandAllZeros and IEEEFloat::isSignificandAllOnes to behave correctly in the case that the size of the significand is a multiple of the width of the integerParts making up the significand.

The patch to IEEEFloat::isSignificandAllOnes fixes bug 34579, and the patch to IEEE:Float:isSignificandAllZeros fixes the unit test "APFloatTest.x87Next" I added here. I have included both in this diff since the changes are very similar.

Patch by Andrew Briand
2020-09-30 16:07:15 -07:00
Xiang1 Zhang 413577a879 [X86] Support Intel Key Locker
Key Locker provides a mechanism to encrypt and decrypt data with an AES key without having access
to the raw key value by converting AES keys into “handles”. These handles can be used to perform the
same encryption and decryption operations as the original AES keys, but they only work on the current
system and only until they are revoked. If software revokes Key Locker handles (e.g., on a reboot),
then any previous handles can no longer be used.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D88398
2020-09-30 18:08:45 +08:00
Mehdi Amini 960535d65a Hint how to get a symbolized stack trace if llvm-symbolizer is not found on crashes
Most users of LLVM tools hit the raw traces and don't know how to get LLVM to
symbolize automatically for them.

When we print the non-symbolized stack trace, we will add information about
how to get it symbolized.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D88269
2020-09-25 01:52:20 +00:00
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
Mehdi Amini 55bb1ba0fd Add support for setting the path to llvm-symbolizer through an environment variable
This allows to point to an executable that isn't named exactly
"llvm-symbolizer" and not necessarily in the current PATH.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D88192
2020-09-24 19:14:04 +00:00
Sanjay Patel e34bd1e0b0 [APFloat] prevent NaN morphing into Inf on conversion (PR43907)
We shift the significand right on a truncation, but that needs to be made NaN-safe:
always set at least 1 bit in the significand.
https://llvm.org/PR43907

See D88238 for the likely follow-up (but needs some plumbing fixes before it can proceed).

Differential Revision: https://reviews.llvm.org/D87835
2020-09-24 14:02:19 -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
Serge Pavlov 590cc068c1 Use different name for auto variable
Without this change GCC 5.4.0 failed to compile JSON.cpp with the error:

    .../llvm-project/llvm/lib/Support/JSON.cpp: In lambda function:
    .../llvm-project/llvm/lib/Support/JSON.cpp:291:29: error: use of 'V' before deduction of 'auto'
           for (const auto &V : *V.getAsArray())
2020-09-24 17:32:24 +07:00
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