Background:

Wasm EH, while using Windows EH (catchpad/cleanuppad based) IR, uses
Itanium-based libraries and ABIs with some modifications.

`__clang_call_terminate` is a wrapper generated in Clang's Itanium C++
ABI implementation. It contains this code, in C-style pseudocode:
```
void __clang_call_terminate(void *exn) {
  __cxa_begin_catch(exn);
  std::terminate();
}
```
So this function is a wrapper to call `__cxa_begin_catch` on the
exception pointer before termination.

In Itanium ABI, this function is called when another exception is thrown
while processing an exception. The pointer for this second, violating
exception is passed as the argument of this `__clang_call_terminate`,
which calls `__cxa_begin_catch` with that pointer and calls
`std::terminate` to terminate the program.

The spec (https://libcxxabi.llvm.org/spec.html) for `__cxa_begin_catch`
says,
```
When the personality routine encounters a termination condition, it
will call __cxa_begin_catch() to mark the exception as handled and then
call terminate(), which shall not return to its caller.
```

In wasm EH's Clang implementation, this function is called from
cleanuppads that terminates the program, which we also call terminate
pads. Cleanuppads normally don't access the thrown exception and the
wasm backend converts them to `catch_all` blocks. But because we need
the exception pointer in this cleanuppad, we generate
`wasm.get.exception` intrinsic (which will eventually be lowered to
`catch` instruction) as we do in the catchpads. But because terminate
pads are cleanup pads and should run even when a foreign exception is
thrown, so what we have been doing is:
1. In `WebAssemblyLateEHPrepare::ensureSingleBBTermPads()`, we make sure
terminate pads are in this simple shape:
```
%exn = catch
call @__clang_call_terminate(%exn)
unreachable
```
2. In `WebAssemblyHandleEHTerminatePads` pass at the end of the
pipeline, we attach a `catch_all` to terminate pads, so they will be in
this form:
```
%exn = catch
call @__clang_call_terminate(%exn)
unreachable
catch_all
call @std::terminate()
unreachable
```
In `catch_all` part, we don't have the exception pointer, so we call
`std::terminate()` directly. The reason we ran HandleEHTerminatePads at
the end of the pipeline, separate from LateEHPrepare, was it was
convenient to assume there was only a single `catch` part per `try`
during CFGSort and CFGStackify.

---

Problem:

While it thinks terminate pads could have been possibly split or calls
to `__clang_call_terminate` could have been duplicated,
`WebAssemblyLateEHPrepare::ensureSingleBBTermPads()` assumes terminate
pads contain no more than calls to `__clang_call_terminate` and
`unreachable` instruction. I assumed that because in LLVM very limited
forms of transformations are done to catchpads and cleanuppads to
maintain the scoping structure. But it turned out to be incorrect;
passes can merge cleanuppads into one, including terminate pads, as long
as the new code has a correct scoping structure. One pass that does this
I observed was `SimplifyCFG`, but there can be more. After this
transformation, a single cleanuppad can contain any number of other
instructions with the call to `__clang_call_terminate` and can span many
BBs. It wouldn't be practical to duplicate all these BBs within the
cleanuppad to generate the equivalent `catch_all` blocks, only with
calls to `__clang_call_terminate` replaced by calls to `std::terminate`.

Unless we do more complicated transformation to split those calls to
`__clang_call_terminate` into a separate cleanuppad, it is tricky to
solve.

---

Solution (?):

This CL just disables the generation and use of `__clang_call_terminate`
and calls `std::terminate()` directly in its place.

The possible downside of this approach can be, because the Itanium ABI
intended to "mark" the violating exception handled, we don't do that
anymore. What `__cxa_begin_catch` actually does is increment the
exception's handler count and decrement the uncaught exception count,
which in my opinion do not matter much given that we are about to
terminate the program anyway. Also it does not affect info like stack
traces that can be possibly shown to developers.

And while we use a variant of Itanium EH ABI, we can make some
deviations if we choose to; we are already different in that in the
current version of the EH spec we don't support two-phase unwinding. We
can possibly consider a more complicated transformation later to
reenable this, but I don't think that has high priority.

Changes in this CL contains:
- In Clang, we don't generate a call to `wasm.get.exception()` intrinsic
  and `__clang_call_terminate` function in terminate pads anymore; we
  simply generate calls to `std::terminate()`, which is the default
  implementation of `CGCXXABI::emitTerminateForUnexpectedException`.
- Remove `WebAssembly::ensureSingleBBTermPads() function and
  `WebAssemblyHandleEHTerminatePads` pass, because terminate pads are
  already `catch_all` now (because they don't need the exception
  pointer) and we don't need these transformations anymore.
- Change tests to use `std::terminate` directly. Also removes tests that
  tested `LateEHPrepare::ensureSingleBBTermPads` and
  `HandleEHTerminatePads` pass.
- Drive-by fix: Add some function attributes to EH intrinsic
  declarations

Fixes https://github.com/emscripten-core/emscripten/issues/13582.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D97834

This reverts commit 51bd42ef.

This code assumed that FP math was only permissable if it was
fully "fast", so it hard-coded "fast" when creating new instructions.

The underlying code already allows matching recurrences/reductions
that are only "reassoc", so this change should prevent the potential
miscompile seen in the test diffs (we created "fast" ops even though
none existed in the original code).

I don't know if we need to create the temporary IRBuilder objects
used here, so that could be follow-up clean-up.

There's an open question about whether we should require "nsz" in
addition to "reassoc" here. InstCombine uses that combo for its
reassociative folds, but I think codegen is not as strict.

Enable Attributor's heap-to-stack to lower unbounded allocations given a max size of -1

Differential Revision: https://reviews.llvm.org/D97873

Use a WeakTrackingVH to cope with the stmt emission logic that cleans up
unreachable blocks. This invalidates the reference to the deferred
replacement placeholder. Cope with it.

Fixes PR25102 (from 2015!)

Preparation to make AliasResult scoped enumeration.

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D97973

The hazard where a VMEM reads an SGPR written by a VALU counts as a data
dependency hazard, so no nops are required on GFX10. Tested with Vulkan
CTS on GFX10.1 and GFX10.3.

Differential Revision: https://reviews.llvm.org/D97926

To unify the naming scheme across all ops in the SPIR-V dialect, we are
moving from spv.camelCase to spv.CamelCase everywhere.

Reviewed By: antiagainst

Differential Revision: https://reviews.llvm.org/D97919

Differential Revision: https://reviews.llvm.org/D89945

To unify the naming scheme across all ops in the SPIR-V dialect, we are
moving from `spv.camelCase` to `spv.CamelCase` everywhere.

Reviewed By: antiagainst

Differential Revision: https://reviews.llvm.org/D97917

To avoid assembler errors.

Reviewed By: sfertile

Differential Revision: https://reviews.llvm.org/D97418

To unify the naming scheme across all ops in the SPIR-V dialect, we are
moving from spv.camelCase to spv.CamelCase everywhere.

Differential Revision: https://reviews.llvm.org/D97920

BasicAA knows how to analyze phis, but to control compile time, we're fairly limited in doing so. This patch loosens that restriction just slightly when there is exactly one phi input (after discounting induction variable increments). The result of this is that we can handle more cases around nested and sibling loops with pointer induction variables.

A few points to note.
* This is deliberately extremely restrictive about recursing through at most one input of the phi.  There's a known general problem with BasicAA sometimes hitting exponential compile time already, and this patch makes every effort not to compound the problem.  Once the root issue is fixed, we can probably loosen the restrictions here a bit.
* As seen in the test file, we're still missing cases which aren't *directly* based on phis (e.g. using the indvar increment). I believe this to be a separate problem and am going to explore this in another patch once this one lands.
* As seen in the test file, this results in the unfortunate fact that using phivalues sometimes results in worse quality results. I believe this comes down to an oversight in how recursive phi detection was implemented for phivalues. I'm happy to tackle this in a follow up change.

Differential Revision: https://reviews.llvm.org/D97401

Now that attributes can be generated using ODS, we can move the builtin attributes as well. This revision removes a majority of the builtin attributes with a few left for followup revisions. The attributes moved to ODS in this revision are: AffineMapAttr, ArrayAttr, DictionaryAttr, IntegerSetAttr, StringAttr, SymbolRefAttr, TypeAttr, and UnitAttr.

Differential Revision: https://reviews.llvm.org/D97591

The value type of the attribute can be specified by either overriding the typeBuilder field on the AttrDef, or by providing a parameter of type `AttributeSelfTypeParameter`. This removes the need to define custom storage class constructors for attributes that have a value type other than NoneType.

Differential Revision: https://reviews.llvm.org/D97590

Add more expectations in vector.ll and select.ll based on command-line option combinations.
Also, remove hard-coded shadow width references to enable fast8 transition.

Reviewed By: stephan.yichao.zhao

Differential Revision: https://reviews.llvm.org/D97903

This enhances the auto-init remark with information about the variable
that is auto-initialized.

This is based of debug info if available, or alloca names (mostly for
development purposes).

```
auto-init.c:4:7: remark: Call to memset inserted by -ftrivial-auto-var-init. Memory operation size: 4096 bytes.Variables: var (4096 bytes). [-Rpass-missed=annotation-remarks]
  int var[1024];
      ^
```

This allows to see things like partial initialization of a variable that
the optimizer won't be able to completely remove.

Differential Revision: https://reviews.llvm.org/D97734

This is recommit of 4c8fb7dd.
MIR in one unit test had mismatched types.

For vectors we consider a bit as known if it is the same for all demanded
vector elements (all elements by default). KnownBits BitWidth for vector
type is size of vector element. Add support for G_BUILD_VECTOR.
This allows combines of urem_pow2_to_mask in pre-legalizer combiner.

Differential Revision: https://reviews.llvm.org/D96122

This reverts commit 7479a2e0.

This commit causes compile errors on clang-x64-windows-msvc, so I'm
reverting the patch for now.

For reference, the error in question is:

```
error C2280: 'llvm::raw_ostream_iterator<char,char>
&llvm::raw_ostream_iterator<char,char>::operator =(const
llvm::raw_ostream_iterator<char,char> &)': attempting to reference a deleted
function

note: compiler has generated 'llvm::raw_ostream_iterator<char,char>::operator ='
here

note: 'llvm::raw_ostream_iterator<char,char>
&llvm::raw_ostream_iterator<char,char>::operator =(const
llvm::raw_ostream_iterator<char,char> &)': function was implicitly deleted
because 'llvm::raw_ostream_iterator<char,char>' has a data member
'llvm::raw_ostream_iterator<char,char>::OutStream' of reference type
```

This change adds a new IR noundef attribute, which denotes when a function call argument or return val may never contain uninitialized bits.

In MemorySanitizer, this attribute enables optimizations which decrease instrumented code size by up to 17% (measured with an instrumented build of clang) . I'll introduce the change allowing msan to take advantage of this information in a separate patch.

Differential Revision: https://reviews.llvm.org/D81678

We're having flaky failures on this test on the sanitizer slow
buildbot. Not per-run flaky, but it'll be green for a while, then red
for a while. I suspect that changes in codegen are causing the
LLVM_VP_MAX_NUM_VALS_PER_SITE=150 to be above and below the limit
sporadically. The limit on my machine using lld and a non-bootstrapped
compiler is 175, but the bot uses GNU ld and ld.gold at different
points, which could be affecting behaviour.

Change this threshold to LLVM_VP_MAX_NUM_VALS_PER_SITE=130 in order to
try and get it below the failure point, at least for the foreseeable
future.

http://lab.llvm.org:8011/#/builders/37/builds/2744

[clang-tidy] Add options to describe individual core increments to readability-function-cognitive-complexity check.

Often you are only interested in the overall cognitive complexity of a
function and not every individual increment. Thus the flag
'DescribeBasicIncrements' is added. If it is set to 'true', each increment
is flagged. Otherwise, only the complexity of function with complexity
of at least the threshold are flagged.

By default 'DescribeBasisIncrements' is set to 'true', which is the original behavior of the check.

Added a new test for different flag combinations.

(The option to ignore macros which was original part of this patch will be added in another path)

Reviewed By: lebedev.ri

Differential Revision: https://reviews.llvm.org/D96281

This function simplifies calling the getChecked methods on Attributes and Types from within the parser, and removes any need to use `getEncodedSourceLocation` for these methods (by using an SMLoc instead). This is much more efficient than using an mlir::Location, as the encoding process to produce an mlir::Location is inefficient and undesirable for parsing (locations used during parsing should not persist afterwards unless otherwise necessary).

Differential Revision: https://reviews.llvm.org/D97900

Revert "Revert "[Coverage] Emit gap region between statements if first statements contains terminate statements.""

Reland with update on test case ContinuousSyncmode/basic.c.

This reverts commit fe5c2c3c.

Since multiple dylibs can be defined in one TBD, this is
necessary to avoid confusion.

Reviewed By: #lld-macho, oontvoo

Differential Revision: https://reviews.llvm.org/D97905

Previously, we were loading re-exports without checking whether
they were compatible with our target. Prior to {D97209}, it meant that
we were defining dylib symbols that were invalid -- usually a silent
failure unless our binary actually used them. D97209 exposed this as an
explicit error.

Along the way, I've extended our TAPI compatibility check to cover the
platform as well, instead of just checking the arch. To this end, I've
replaced MachO::Architecture with MachO::Target in our Config struct.

Reviewed By: #lld-macho, oontvoo

Differential Revision: https://reviews.llvm.org/D97867

The reexport-nested-libs test added in D97438 was a bit wonky.

First, it was linking against libReexportSystem.tbd which targets the
iOS simulator, and which in turn attempted to re-export the iOS
simulator's libSystem. However, due to the way `-syslibroot` works, it
was actually re-exporting the macOS libSystem.

As a result, the test was not actually able to resolve the symbols in
the desired libSystem. I'm guessing that @oontvoo was confused by this
and therefore included those symbols in libReexportSystem.tbd itself.
But this means that the test wasn't actually testing the resolution of
re-exported symbols (though it did at least verify that the re-exported
libraries could be located).

After some consideration, I figured that stub-link.s could be extended
to cover what reexport-nested-libs.s was attempting to do. The test
targets macOS, so we only have one `-syslibroot` and no chance of
confusion.

Reviewed By: #lld-macho, oontvoo

Differential Revision: https://reviews.llvm.org/D97866

Suppose we are linking against libFoo, which re-exports the
implicitly-bound libSystem, which in turn re-exports some
non-explicitly-bound library like `/usr/lib/system/libsystem_c.dylib`.
Then any bindings we have to a symbol in libsystem_c should use
libSystem (and not libFoo) as the umbrella library.

Reviewed By: #lld-macho, smeenai

Differential Revision: https://reviews.llvm.org/D97865

This change adds '-use-interfacestub' option to allow llvm-ifs
to use InterfaceStub lib when generating ELF binary.

Differential Revision: https://reviews.llvm.org/D94461

When using `OptionGroupPythonClassWithDict` options in an `OptionGroup`
with other `Options`, it can happen that the combinaison of some options
of each group makes the command invalid.

To solve that issue, this patch adds a bitmask argument to the
`OptionGroupPythonClassWithDict` constuctor that is used to mark each
option as required (or not).

If the `required_options` bitmask isn't passed to the constructor, the
class will keep its default behaviour, making the `--script-class` and
`--python-function` required.

rdar://65508855

Differential Revision: https://reviews.llvm.org/D97910



Signed-off-by: Med Ismail Bennani <medismail.bennani@gmail.com>