This patch adds the following compiler frontend driver options:
  * -fdebug-unparse (f18 spelling: -funparse)
  * -fdebug-unparse-with-symbols (f18 spelling: -funparse-with-symbols)
The new driver will only accept the new spelling. `f18` will accept both
the original and the new spelling.

A new base class for frontend actions is added: `PrescanAndSemaAction`.
This is added to reduce code duplication that otherwise these new
options would lead to. Implementation from
  * `ParseSyntaxOnlyAction::ExecutionAction`
is moved to:
  * `PrescanAndSemaAction::BeginSourceFileAction`
This implementation is now shared between:
  * PrescanAndSemaAction
  * ParseSyntaxOnlyAction
  * DebugUnparseAction
  * DebugUnparseWithSymbolsAction

All tests that don't require other yet unimplemented options are
updated. This way `flang-new -fc1` is used instead of `f18` when
`FLANG_BUILD_NEW_DRIVER` is set to `On`. In order to facilitate this,
`%flang_fc1` is added in the LIT configuration (lit.cfg.py).

`asFortran` from f18.cpp is duplicated as `getBasicAsFortran` in
FrontendOptions.cpp. At this stage it's hard to find a good place to
share this method. I suggest that we revisit this once a switch from
`f18` to `flang-new` is complete.

Differential Revision: https://reviews.llvm.org/D96483

This patch changes costAndCollectOperands to use InstructionCost for
accumulated cost values.

isHighCostExpansion will return true if the cost has exceeded the budget.

Reviewed By: CarolineConcatto, ctetreau

Differential Revision: https://reviews.llvm.org/D92238

This adds the lowering for expm1 for GPU backends.

Differential Revision: https://reviews.llvm.org/D96756

The following _action_ options are always used with `-fsyntax-only`
(also an _action_ option):
  * -fdebug-dump-symbols
  * -fdebug-dump-parse-tree
This patch makes the above options imply `-fsyntax-only`.

From the perspective of `f18` this change saves typing and is otherwise
a non-functional change. But it will simplify things in the new driver,
`flang-new`, in which only the last action option is taken into account
and executed. In other words, the following would only run
`-fsyntax-only`:
```
flang-new -fdebug-dump-symbols -fsyntax-only <input>
```
whereas this would only run `-fdebug-dump-symbols`:
```
flang-new -fsyntax-only -fdebug-dump-symbols <input>
```

Differential Revision: https://reviews.llvm.org/D96528

The patch also does some cleanup on the interface of the entry
points from TargetFinder into the heuristic resolution code.

Since the heuristic resolver is created in a place where the
ASTContext is available, it can store the ASTContext and the
NameFactory hack can be removed.

Differential revision: https://reviews.llvm.org/D92290

This patch updates codegen to use VPValues to manage the generated
scalarized instructions.

Reviewed By: gilr

Differential Revision: https://reviews.llvm.org/D92285

Differential Revision: https://reviews.llvm.org/D96704

SliceAnalysis originally was developed in the context of affine.for within mlfunc.
It predates the notion of region.
This revision updates it to not hardcode specific ops like scf::ForOp.
When rooted at an op, the behavior of the slice computation changes as it recurses into the regions of the op. This does not support gathering all values transitively depending on a loop induction variable anymore.
Additional variants rooted at a Value are added to also support the existing behavior.

Differential revision: https://reviews.llvm.org/D96702

The GPUDivergenceAnalysis is now renamed to just "DivergenceAnalysis"
since there is no conflict with LegacyDivergenceAnalysis. In the
legacy PM, this analysis can only be used through the legacy DA
serving as a wrapper. It is now made available as a pass in the new
PM, and has no relation with the legacy DA.

The new DA currently cannot handle irreducible control flow; its
presence can cause the analysis to run indefinitely. The analysis is
now modified to detect this and report all instructions in the
function as divergent. This is super conservative, but allows the
analysis to be used without hanging the compiler.

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D96615

The execl function takes both the executable and argv[0].

Delete unused `EnableTracer()` and `SetTracer()` functions on `Thread`. By deleting
these, their `ThreadPlan` counterparts also become unused.

Then, by deleting `ThreadPlanStack::EnableTracer`, `EnableSingleStep` becomes unused.
With no more callers to `EnableSingleStep`, the value `m_single_step` is always true and
can be removed as well.

Differential Revision: https://reviews.llvm.org/D96666

`GetRealStopInfo` has only one call site, and in that call site a reference to the
concrete thread plan is available (`ThreadPlanCallUserExpression`), from which
`GetRealStopInfo` can be called.

Differential Revision: https://reviews.llvm.org/D96687

Correct `RestoreThreadState` to a `void` return type. Also, update the signature of its
callee, `Thread::RestoreThreadStateFromCheckpoint`, by updating it to a `void` return
type, and making it non-`virtual`.

Differential Revision: https://reviews.llvm.org/D96688

This fixes a bug where an object can get deallocated before reaching the
end of its full formal lifetime.

rdar://72110887
rdar://74123176

This stops tablegen from generating patterns with the opposite type
in the opposite HwMode. This just adds wasted bytes to the isel table.

This reduces the isel table by about 1800 bytes.

The API is a bit awkward since you need to index into an array in the
passed struct. I guess an alternative would be to pass all of the
individual fields.

Return the best covering index, and additional needed to complete the
mask. This logically belongs in TargetRegisterInfo, although I ended
up not needing it for why I originally split this out.

Differential Revision: https://reviews.llvm.org/D96701

The namespace is unnecessary, and libc++ style is not to include it on type names.
(As opposed to function names, where qualification affects ADL; and in certain
function signatures where `std::` and `_VSTD::` might be mangled differently.
This is none of those situations.)

This is annoying because the condition code legalization belongs
to LegalizeDAG, but our custom handler runs in Legalize vector ops
which occurs earlier.

This adds some of the mask binary operations so that we can combine
multiple compares that we need for expansion.

I've also fixed up RISCVISelDAGToDAG.cpp to handle copies of masks.

This patch contains a subset of the integer setcc patch as well.
That patch is dependent on the integer binary ops patch. I'll rebase
based on what order the patches go in.

Reviewed By: frasercrmck

Differential Revision: https://reviews.llvm.org/D96567

[RISCV][LegalizeTypes] Try to expand BITREVERSE before promoting if the promoted BITREVERSE would expand anyway.

If we're going to end up expanding anyway, we should do it early
so we don't create extra operations to handle the bytes added by
promotion.

Simlilar was done for BSWAP previously.

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D96681

TestMultipleTargets.py fails randomly on Arm/AArch64 Linux buildbot with
no reasonable clues. I am marking it skipped for avoiding LLDB buildbot
failures due to this test.

In the motivating example from https://llvm.org/PR49171 and
reduced test here, we would unroll and clone assumes so much
that compile-time effectively became infinite while analyzing
all of those assumes.

Always turn on LIBCXX_ENABLE_NEW_DELETE_DEFINITIONS, if libcxxrt is used
as the C++ ABI library, since libcxxrt does not provide the full set
ofnew and delete operators. In particular, the aligned versions of these
operators are completely missing. This primarily addresses builds on
FreeBSD, as this platform uses libcxxrt by default.

Also, attempt to provide a FreeBSD.cmake cache file, with hopefully sane
settings, partially copied from the Apple.cmake cache file. This needs
more work, probably some additions to ci build scripts (although I am
not aware of any 'official' FreeBSD build bots).

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D96720

This commit fixes how metadata is handled in CloneModule to be sound,
and improves how it's handled in CloneFunctionInto (although the latter
is still awkward when called within a module).

Ruiling Song pointed out in PR48841 that CloneModule was changed to
unsoundly use the RF_ReuseAndMutateDistinctMDs flag (renamed in
fa35c1f8 for clarity). This flag papered
over a crash caused by other various changes made to CloneFunctionInto
over the past few years that made it unsound to use cloning between
different modules.

(This commit partially addresses PR48841, fixing the repro from
preprocessed source but not textual IR. MDNodeMapper::mapDistinctNode
became unsound in df763188 and this
commit does not address that regression.)

RF_ReuseAndMutateDistinctMDs is designed for the IRMover to use,
avoiding unnecessary clones of all referenced metadata when linking
between modules (with IRMover, the source module is discarded after
linking). It never makes sense to use when you're not discarding the
source. This commit drops its incorrect use in CloneModule.

Sadly, the right thing to do with metadata when cloning a function is
complicated, and this patch doesn't totally fix it.

The first problem is that there are two different types of referenceable
metadata and it's not obvious what to with one of them when remapping.

- `!0 = !{!1}` is metadata's version of a constant. Programatically it's
  called "uniqued" (probably a better term would be "constant") because,
  like `ConstantArray`, it's stored in uniquing tables. Once it's
  constructed, it's illegal to change its arguments.
- `!0 = distinct !{!1}` is a bit closer to a global variable. It's legal
  to change the operands after construction.

What should be done with distinct metadata when cloning functions within
the same module?

- Should new, cloned nodes be created?
- Should all references point to the same, old nodes?

The answer depends on whether that metadata is effectively owned by a
function.

And that's the second problem. Referenceable metadata's ownership model
is not clear or explicit. Technically, it's all stored on an
LLVMContext. However, any metadata that is `distinct`, that transitively
references a `distinct` node, or that transitively references a
GlobalValue is specific to a Module and is effectively owned by it. More
specifically, some metadata is effectively owned by a specific Function
within a module.

Effectively function-local metadata was introduced somewhere around
c10d0e5c, which made it illegal for two
functions to share a DISubprogram attachment.

When cloning a function within a module, you need to clone the
function-local debug info and suppress cloning of global debug info (the
status quo suppresses cloning some global debug info but not all). When
cloning a function to a new/different module, you need to clone all of
the debug info.

Here's what I think we should do (eventually? soon? not this patch
though):
- Distinguish explicitly (somehow) between pure constant metadata owned
  by the LLVMContext, global metadata owned by the Module, and local
  metadata owned by a GlobalValue (such as a function).
- Update CloneFunctionInto to trigger cloning of all "local" metadata
  (only), perhaps by adding a bit to RemapFlag. Alternatively, split
  out a separate function CloneFunctionMetadataInto to prime the
  metadata map that callers are updated to call ahead of time as
  appropriate.

Here's the somewhat more isolated fix in this patch:
- Converted the `ModuleLevelChanges` parameter to `CloneFunctionInto` to
  an enum called `CloneFunctionChangeType` that is one of
  LocalChangesOnly, GlobalChanges, DifferentModule, and ClonedModule.
- The code maintaining the "functions uniquely own subprograms"
  invariant is now only active in the first two cases, where a function
  is being cloned within a single module. That's necessary because this
  code inhibits cloning of (some) "global" metadata that's effectively
  owned by the module.
- The code maintaining the "all compile units must be explicitly
  referenced by !llvm.dbg.cu" invariant is now only active in the
  DifferentModule case, where a function is being cloned into a new
  module in isolation.
- CoroSplit.cpp's call to CloneFunctionInto in CoroCloner::create
  uses LocalChangeOnly, since fa635d73
  only set `ModuleLevelChanges` to trigger cloning of local metadata.
- CloneModule drops its unsound use of RF_ReuseAndMutateDistinctMDs
  and special handling of !llvm.dbg.cu.
- Fixed some outdated header docs and left a couple of FIXMEs.

Differential Revision: https://reviews.llvm.org/D96531

This restores the behavior before 964f8103, which broke 2 tests:
  LLVM :: tools/llvm-lto2/X86/pipeline.ll
  lld :: ELF/lto/ltopasses-custom.ll

We are using AtomicNoRet map in multiple places to determine
if an instruction atomic, rtn or nortn atomic. This method
does not work always since we have some instructions which
only has rtn or nortn version.

One such instruction is ds_wrxchg_rtn_b32 which does not have
nortn version. This has caused changes in memory legalizer
tests.

Differential Revision: https://reviews.llvm.org/D96639

The few options are niche. They solved a problem which was traditionally solved
with more shell commands (`llvm-readelf -n` fetches the Build ID. Then
`ln` is used to hard link the file to a directory derived from the Build ID.)

Due to limitation, they are no longer used by Fuchsia and they don't appear to
be used elsewhere (checked with Google Search and Debian Code Search). So delete
them without a transition period.

Announcement: https://lists.llvm.org/pipermail/llvm-dev/2021-February/148446.html

Differential Revision: https://reviews.llvm.org/D96310

Even code in target and declare target regions might not be emitted.
With this patch we delay more diagnostics and use laziness and linkage
to determine if a function is emitted (for the device). Note that we
still eagerly emit diagnostics for target regions, unfortunately, see
the TODO for the reason.

This hopefully fixes PR48933.

Reviewed By: JonChesterfield

Differential Revision: https://reviews.llvm.org/D95928

Type errors in function declarations were not (always) diagnosed prior
to this patch. Furthermore, certain remarks did not get associated
properly which caused them to be emitted multiple times.

Reviewed By: JonChesterfield

Differential Revision: https://reviews.llvm.org/D95912

This will highlight the effective changes in subsequent commits.

Reviewed By: ABataev

Differential Revision: https://reviews.llvm.org/D95903

This patch enables AsmPrinter support for complex expression with
entry values. It shouldn't AsmPrinter's call whether these are safe or
not but the pass who introduces the DW_OP_LLVM_entry_value. This patch
on its own has no effect on clang.

Differential Revision: https://reviews.llvm.org/D96559

Announcement: https://lists.llvm.org/pipermail/llvm-dev/2021-February/148446.html

Differential Revision: https://reviews.llvm.org/D96360