Commit Graph

1555 Commits

Author SHA1 Message Date
Wouter van Oortmerssen 4a0c89a6cf [WebAssembly] Fix fixBrTableIndex removing instruction without checking uses
Fixes: https://bugs.llvm.org/show_bug.cgi?id=52352
Differential Revision: https://reviews.llvm.org/D113230
2021-11-08 15:53:44 -08:00
Nikita Popov a8c318b50e [BasicAA] Use index size instead of pointer size
When accumulating the GEP offset in BasicAA, we should use the
pointer index size rather than the pointer size.

Differential Revision: https://reviews.llvm.org/D112370
2021-11-07 18:56:11 +01:00
Kazu Hirata 22e21da47d [WebAssembly] Remove unused declaration SelectExternRefAddr (NFC) 2021-11-06 19:31:22 -07:00
Kazu Hirata 14d656b3d8 [Target] Use llvm::reverse (NFC) 2021-11-06 13:08:21 -07:00
Quinn Pham c71fbdd87b [NFC] Inclusive language: Remove instances of master in URLs
[NFC] This patch fixes URLs containing "master". Old URLs were either broken or
redirecting to the new URL.

Reviewed By: #libc, ldionne, mehdi_amini

Differential Revision: https://reviews.llvm.org/D113186
2021-11-05 08:48:41 -05:00
Wouter van Oortmerssen a320f877ce [WebAssembly] Fix debug locations for ExplicitLocals pass
This is a reworked version of the reverted patch: https://reviews.llvm.org/D112487
Note that
a) it doesn't need the test changes anymore, and
b) I checked at least locally it passes other.test_pthread_lsan_leak

Differential Revision: https://reviews.llvm.org/D113208
2021-11-04 11:38:03 -07:00
Wouter van Oortmerssen ac65366485 [WebAssembly] support "return" and unreachable code in asm type checker
To support return (it not being supported well was the ground cause for
https://github.com/WebAssembly/wasi-sdk/issues/200) we also have to have
at least a basic notion of unreachable, which in this case just means to stop
type checking until there is an end_block (an incoming control flow edge).
This is conservative (may miss on some type checking opportunities) but is
simple and an improvement over what we had before.

Differential Revision: https://reviews.llvm.org/D112953
2021-11-01 15:42:58 -07:00
Sam Clegg 3b039c68f2 Revert "[WebAssembly] Fix debug locations for ExplicitLocals pass"
This reverts commit a66451ebbe.

This caused a failure when integrated with emscripten:
https://ci.chromium.org/ui/p/emscripten-releases/builders/try/linux/b8832019855439718609/overview
2021-10-29 13:34:18 -07:00
Thomas Lively fb67f3d969 [WebAssembly] Add prototype relaxed float to int trunc instructions
Add i32x4.relaxed_trunc_f32x4_s, i32x4.relaxed_trunc_f32x4_u,
i32x4.relaxed_trunc_f64x2_s_zero, i32x4.relaxed_trunc_f64x2_u_zero.

These are only exposed as builtins, and require user opt-in.

Differential Revision: https://reviews.llvm.org/D112186
2021-10-28 14:01:53 -07:00
Wouter van Oortmerssen a66451ebbe [WebAssembly] Fix debug locations for ExplicitLocals pass
Differential Revision: https://reviews.llvm.org/D112487
2021-10-28 12:35:46 -07:00
Wouter van Oortmerssen 5694dbccc3 [WebAssembly] support Memory64 in target_features section
Differential Revision: https://reviews.llvm.org/D112266
2021-10-25 09:31:45 -07:00
Kazu Hirata 6fe949c4ed [Target, Transforms] Use StringRef::contains (NFC) 2021-10-22 08:52:33 -07:00
Zhi An Ng e1fb13401e [WebAssembly] Add prototype relaxed float min max instructions
Add relaxed. f32x4.min, f32x4.max, f64x2.min, f64x2.max. These are only
exposed as builtins, and require user opt-in.

Differential Revision: https://reviews.llvm.org/D112146
2021-10-20 09:41:51 -07:00
Craig Topper fe1f0de003 [RISCV][WebAssembly][TargetLowering] Allow expandCTLZ/expandCTTZ to rely on CTPOP expansion for vectors.
Our fallback expansion for CTLZ/CTTZ relies on CTPOP. If CTPOP
isn't legal or custom for a vector type we would scalarize the
CTLZ/CTTZ. This is different than CTPOP itself which would use a
vector expansion.

This patch teaches expandCTLZ/CTTZ to rely on the vector CTPOP
expansion instead of scalarizing. To do this I had to add additional
checks to make sure the operations used by CTPOP expansions are all
supported. Some of the operations were already needed for the CTLZ/CTTZ
expansion.

This is a huge improvement to the RISCV which doesn't have a scalar
ctlz or cttz in the base ISA.

For WebAssembly, I've added Custom lowering to keep the scalarizing
behavior. I've also extended the scalarizing to CTPOP.

Differential Revision: https://reviews.llvm.org/D111919
2021-10-20 07:46:41 -07:00
Paulo Matos 6d0c7bc17d [WebAssembly] Implementation of table.get/set for reftypes in LLVM IR
This change implements new DAG nodes TABLE_GET/TABLE_SET, and lowering
methods for load and stores of reference types from IR arrays. These
global LLVM IR arrays represent tables at the Wasm level.

Differential Revision: https://reviews.llvm.org/D111154
2021-10-20 10:31:31 +02:00
Zhi An Ng 2542bfa43a [WebAssembly] Add prototype relaxed swizzle instructions
Add i8x16 relaxed_swizzle instructions. These are only
exposed as builtins, and require user opt-in.

Differential Revision: https://reviews.llvm.org/D112022
2021-10-19 17:53:04 -07:00
Kazu Hirata 8568ca789e Use llvm::erase_if (NFC) 2021-10-18 09:33:42 -07:00
Zhi An Ng da07942834 [WebAssembly] Add prototype relaxed laneselect instructions
Add i8x16, i16x8, i32x4, i64x2 laneselect instructions. These are only
exposed as builtins, and require user opt-in.
2021-10-15 17:45:09 -07:00
Heejin Ahn 9261ee32dc [WebAssembly] Make EH work with dynamic linking
This makes Wasm EH work with dynamic linking. So far we were only able
to handle destructors, which do not use any tags or LSDA info.

1. This uses `TargetExternalSymbol` for `GCC_except_tableN` symbols,
   which points to the address of per-function LSDA info. It is more
   convenient to use than `MCSymbol` because it can take additional
   target flags.

2. When lowering `wasm_lsda` intrinsic, if PIC is enabled, make the
   symbol relative to `__memory_base` and generate the `add` node. If
   PIC is disabled, continue to use the absolute address.

3. Make tag symbols (`__cpp_exception` and `__c_longjmp`) undefined in
   the backend, because it is hard to make it work with dynamic
   linking's loading order. Instead, we make all tag symbols undefined
   in the LLVM backend and import it from JS.

4. Add support for undefined tags to the linker.

Companion patches:
- https://github.com/WebAssembly/binaryen/pull/4223
- https://github.com/emscripten-core/emscripten/pull/15266

Reviewed By: sbc100

Differential Revision: https://reviews.llvm.org/D111388
2021-10-12 23:28:27 -07:00
Reid Kleckner b3a6d096d7 Fix shlib builds for all lib/Target/*/TargetInfo libs
They all must depend on MC now that the target registry is in MC.
Also fix llvm-cxxdump
2021-10-08 15:21:13 -07:00
Reid Kleckner 89b57061f7 Move TargetRegistry.(h|cpp) from Support to MC
This moves the registry higher in the LLVM library dependency stack.
Every client of the target registry needs to link against MC anyway to
actually use the target, so we might as well move this out of Support.

This allows us to ensure that Support doesn't have includes from MC/*.

Differential Revision: https://reviews.llvm.org/D111454
2021-10-08 14:51:48 -07:00
Jack Andersen bd4dad87f4 [MachineInstr] Move MIParser's DBG_VALUE RegState::Debug invariant into MachineInstr::addOperand
Based on the reasoning of D53903, register operands of DBG_VALUE are
invariably treated as RegState::Debug operands. This change enforces
this invariant as part of MachineInstr::addOperand so that all passes
emit this flag consistently.

RegState::Debug is inconsistently set on DBG_VALUE registers throughout
LLVM. This runs the risk of a filtering iterator like
MachineRegisterInfo::reg_nodbg_iterator to process these operands
erroneously when not parsed from MIR sources.

This issue was observed in the development of the llvm-mos fork which
adds a backend that relies on physical register operands much more than
existing targets. Physical RegUnit 0 has the same numeric encoding as
$noreg (indicating an undef for DBG_VALUE). Allowing debug operands into
the machine scheduler correlates $noreg with RegUnit 0 (i.e. a collision
of register numbers with different zero semantics). Eventually, this
causes an assert where DBG_VALUE instructions are prohibited from
participating in live register ranges.

Reviewed By: MatzeB, StephenTozer

Differential Revision: https://reviews.llvm.org/D110105
2021-10-07 16:08:52 +01:00
Simon Pilgrim 21661607ca [llvm] Replace report_fatal_error(std::string) uses with report_fatal_error(Twine)
As described on D111049, we're trying to remove the <string> dependency from error handling and replace uses of report_fatal_error(const std::string&) with the Twine() variant which can be forward declared.
2021-10-06 12:04:30 +01:00
Paulo Matos 0c7495848a [WebAssembly] Fix call_indirect on funcrefs
The currently implementation of funcrefs is broken since it is putting
the funcref itself on the stack before the call_indirect. Instead what
should be on the stack is the constant 0, which is the index at which
we store the funcref in __funcref_call_table.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D111152
2021-10-06 10:11:53 +02:00
Paulo Matos 91fe069c35 [WebAssembly] De-duplicate WasmAddressSpace and refactor reftype predicates
This is a non-functional change to remove the duplicate
WasmAddressSpace enum and refactor reftype predicates by moving them
to the Utilities source file.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D111144
2021-10-06 09:56:23 +02:00
Heejin Ahn 3ec1760d91 [WebAssembly] Remove WasmTagType
This removes `WasmTagType`. `WasmTagType` contained an attribute and a
signature index:
```
struct WasmTagType {
  uint8_t Attribute;
  uint32_t SigIndex;
};
```

Currently the attribute field is not used and reserved for future use,
and always 0. And that this class contains `SigIndex` as its property is
a little weird in the place, because the tag type's signature index is
not an inherent property of a tag but rather a reference to another
section that changes after linking. This makes tag handling in the
linker also weird that tag-related methods are taking both `WasmTagType`
and `WasmSignature` even though `WasmTagType` contains a signature
index. This is because the signature index changes in linking so it
doesn't have any info at this point. This instead moves `SigIndex` to
`struct WasmTag` itself, as we did for `struct WasmFunction` in D111104.

In this CL, in lib/MC and lib/Object, this now treats tag types in the
same way as function types. Also in YAML, this removes `struct Tag`,
because now it only contains the tag index. Also tags set `SigIndex` in
`WasmImport` union, as functions do.

I think this makes things simpler and makes tag handling more in line
with function handling. These two shares similar properties in that both
of them have signatures, but they are kind of nominal so having the same
signature doesn't mean they are the same element.

Also a drive-by fix: the reserved 'attirubute' part's encoding changed
from uleb32 to uint8 a while ago. This was fixed in lib/MC and
lib/Object but not in YAML. This doesn't change object files because the
field's value is always 0 and its encoding is the same for the both
encoding.

This is effectively NFC; I didn't mark it as such just because it
changed YAML test results.

Reviewed By: sbc100, tlively

Differential Revision: https://reviews.llvm.org/D111086
2021-10-05 17:11:22 -07:00
Kazu Hirata c1e32b3fc0 [Target] Migrate from getNumArgOperands to arg_size (NFC)
Note that getNumArgOperands is considered a legacy name.  See
llvm/include/llvm/IR/InstrTypes.h for details.
2021-10-02 12:06:29 -07:00
Thomas Lively 2f519825ba [WebAssembly] Add prototype relaxed SIMD fma/fms instructions
Add experimental clang builtins, LLVM intrinsics, and backend definitions for
the new {f32x4,f64x2}.{fma,fms} instructions in the relaxed SIMD proposal:
https://github.com/WebAssembly/relaxed-simd/blob/main/proposals/relaxed-simd/Overview.md.
Do not allow these instructions to be selected without explicit user opt-in.

Differential Revision: https://reviews.llvm.org/D110295
2021-09-23 11:01:36 -07:00
Zhi An Ng 1552179ac0 [WebAssembly] Add relaxed-simd feature
This currently only defines a constant, but it the future will be used
to gate builtins for experimenting and prototyping relaxed-simd proposal
(https://github.com/WebAssembly/relaxed-simd/).

Differential Revision: https://reviews.llvm.org/D110111
2021-09-22 14:52:50 -07:00
Simon Pilgrim b1f38a27f0 [Target][CodeGen] Remove default CostKind arguments on inner/impl TTI overrides
Based off a discussion on D110100, we should be avoiding default CostKinds whenever possible.

This initial patch removes them from the 'inner' target implementation callbacks - these should only be used by the main TTI calls, so this should guarantee that we don't cause changes in CostKind by missing it in an inner call. This exposed a few missing arguments in getGEPCost and reduction cost calls that I've cleaned up.

Differential Revision: https://reviews.llvm.org/D110242
2021-09-22 15:28:08 +01:00
Kazu Hirata 85b4b21c8b [llvm] Use make_early_inc_range (NFC) 2021-09-20 19:30:02 -07:00
Kazu Hirata 84b07c9b3a [llvm] Use pop_back_val (NFC) 2021-09-19 13:44:23 -07:00
Heejin Ahn 468c4409f6 Revert "[WebAssembly] Rethrow longjmp in EH handling if EmSjLj is enabled"
This reverts commit b7b4ebbcfa.

Reason: This breaks several code-size tests in Emscripten test suite
because this exports `emscripten_longjmp` for programs that didn't do it
before.
2021-09-14 12:59:42 -07:00
Sam Clegg ef8c9135ef [WebAssembly] Allow import and export of TLS symbols between DSOs
We previously had a limitation that TLS variables could not
be exported (and therefore could also not be imported).  This
change removed that limitation.

Differential Revision: https://reviews.llvm.org/D108877
2021-09-14 06:47:37 -07:00
Cullen Rhodes 6fbc167c0a [WebAssembly] NFC: Remove unused tblgen template args
Identified in D109359.

Reviewed By: aheejin

Differential Revision: https://reviews.llvm.org/D109689
2021-09-14 08:26:15 +00:00
Heejin Ahn e85ed44373 [WebAssembly] Fix a typo in comments 2021-09-14 00:45:02 -07:00
Heejin Ahn c55b6c593b [WebAssembly] Handle _setjmp and _longjmp in SjLj
In some platforms `_setjmp` and `_longjmp` are used instead of `setjmp`
and `longjmp`. This CL adds support for them.

Fixes https://github.com/emscripten-core/emscripten/issues/14999.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D109669
2021-09-13 14:20:04 -07:00
Heejin Ahn b7b4ebbcfa [WebAssembly] Rethrow longjmp in EH handling if EmSjLj is enabled
This is a fix on top of D106525's Case 2. In D106525, in
`runEHOnFunction` which handles Emscripten EH, We rethrow `longjmp` only
when the module has any usage of `setjmp` or `longjmp`. But now Wasm
object files are linked using wasm-ld, the module this pass sees is not
the whole program, and even if this module does not contain any
`longjmp`, another file can contain it and can be linked with the
current module. This enables the rethrowing of longjmp whenever
Emscripten SjLj is enabled, regardless of whether it is used in this
module or not.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D109670
2021-09-13 14:15:25 -07:00
Wouter van Oortmerssen a99fb86c65 [WebAssembly] Change WebAssemblyMCLowerPrePass to ModulePass
It was a FunctionPass before, which subverted its purpose to collect ALL symbols before MCLowering, depending on how LLVM schedules function passes.
Fixes https://bugs.llvm.org/show_bug.cgi?id=51555

Differential Revision: https://reviews.llvm.org/D109202
2021-09-08 10:47:43 -07:00
Heejin Ahn a1d522939c [WebAssembly] Error out on indirect uses of setjmp
Both Wasm & Emscripten SjLj handling has a restriction that `setjmp`
cannot be called indirectly. I thought we have been erroring out on
indirect uses of `setjmp`, but some recent CL disrupted the logic and
we are not erroring out anymore.

We currently
1. Collect functions that contain `setjmp` calls in `SetjmpUsers`. This
   only counts direct calls:
   8f77dc459e/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp (L869-L878)
2. Run `runSjLjOnFunction` only on those `SetjmpUsers`. Within
   `runSjLjOnFunction`, if we see an indirect use of `setjmp`, we error
   out:
   8f77dc459e/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp (L1218-L1221)

So if there are only indirect setjmp calls within the module,
`SetjmpUsers` will be empty, and `runSjLjOnFunction` is not even entered
once. And the indirect `setjmp` call will error out at link time. So in
this CL we check for the indirect uses of `setjmp` upfront before we
enter `runSjLjOnFunction`.

Also this currently errors out on `invoke @setjmp`, which can only occur
when using Wasm EH + Wasm SjLj within a function. We recently added Wasm
SjLj support but we don't support using Wasm EH + Wasm SjLj in the same
function yet. We plan to add this support very soon, so I don't think
it's worth creating another test file just for this. (This is an error
test so it needs its own file)

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D109375
2021-09-07 15:52:58 -07:00
Peter Smith e63455d5e0 [MC] Use local MCSubtargetInfo in writeNops
On some architectures such as Arm and X86 the encoding for a nop may
change depending on the subtarget in operation at the time of
encoding. This change replaces the per module MCSubtargetInfo retained
by the targets AsmBackend in favour of passing through the local
MCSubtargetInfo in operation at the time.

On Arm using the architectural NOP instruction can have a performance
benefit on some implementations.

For Arm I've deleted the copy of the AsmBackend's MCSubtargetInfo to
limit the chances of this causing problems in the future. I've not
done this for other targets such as X86 as there is more frequent use
of the MCSubtargetInfo and it looks to be for stable properties that
we would not expect to vary per function.

This change required threading STI through MCNopsFragment and
MCBoundaryAlignFragment.

I've attempted to take into account the in tree experimental backends.

Differential Revision: https://reviews.llvm.org/D45962
2021-09-07 15:46:19 +01:00
Nikita Popov 66a54af967 [WebAssembly] Support opaque pointers in AddMissingPrototypes
The change here is basically the same as in D108880: Rather than
looking at bitcasts, look at calls and their function type. We
still need to look through bitcasts to find those calls.

The change in llvm/test/CodeGen/WebAssembly/add-prototypes-conflict.ll
is due to different visitation order. add-prototypes-opaque-ptrs.ll
is a copy of add-prototypes.ll with -force-opaque-pointers.

Differential Revision: https://reviews.llvm.org/D109256
2021-09-04 11:25:42 +02:00
Sam Clegg c32884c482 [WebAssembly] Rename WrapperPIC -> WrapperREL. NFC
This ISD node/wrapper represents am address which is relative to a base
address and therefore lowers to `i32.const` rather than `global.get`.

Use this wrapper type for TLS-relative addresses, paving the way for the
non-REL wrapper to be used to external TLS address once those are
supported.

Differential Revision: https://reviews.llvm.org/D109179
2021-09-02 20:04:34 -04:00
Sam Clegg 4664590d53 [WebAssemlby] Remove redundant SDTypeProfile. NFC
I added this back in https://reviews.llvm.org/D54647 but it wasn't
actually needed.

Differential Revision: https://reviews.llvm.org/D109176
2021-09-02 15:21:22 -04:00
Sam Clegg ad2f94f398 [WebAssembly] Fix names of WebAssemblyWrapper SDNodes. NFC
Other platforms all use CamelCase as normal for these wrapper nodes.

Differential Revision: https://reviews.llvm.org/D109172
2021-09-02 13:54:44 -04:00
Heejin Ahn 28780e59f6 [WebAssembly] Add Wasm SjLj support
This add support for SjLj using Wasm exception handling instructions:
https://github.com/WebAssembly/exception-handling/blob/master/proposals/exception-handling/Exceptions.md

This does not yet support the mixed use of EH and SjLj within a
function. It will be added in a follow-up CL.

This currently passes all SjLj Emscripten tests for wasm0/1/2/3/s,
except for the below:
- `test_longjmp_standalone`: Uses Node
- `test_dlfcn_longjmp`: Uses NodeRAWFS
- `test_longjmp_throw`: Mixes EH and SjLj
- `test_exceptions_longjmp1`: Mixes EH and SjLj
- `test_exceptions_longjmp2`: Mixes EH and SjLj
- `test_exceptions_longjmp3`: Mixes EH and SjLj

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D108960
2021-09-02 10:51:02 -07:00
Nikita Popov 7f058ce8c2 [WebAssembly] Support opaque pointers in FixFunctionBitcasts
With opaque pointers, no actual bitcasts will be present. Instead,
there will be a mismatch between the call FunctionType and the
function ValueType. Change the code to collect CallBases
specifically (rather than general Uses) and compare these types.

RAUW is no longer performed, as there would no longer be any
bitcasts that can be RAUWd.

Differential Revision: https://reviews.llvm.org/D108880
2021-09-01 22:17:24 +02:00
Thomas Lively fec4749200 [WebAssembly] Lower v2f32 to v2f64 extending loads with promote_low
Previously extra wide v4f32 to v4f64 extending loads would be legalized to v2f32
to v2f64 extending loads, which would then be scalarized by legalization. (v2f32
to v2f64 extending loads not produced by legalization were already being emitted
correctly.) Instead, mark v2f32 to v2f64 extending loads as legal and explicitly
lower them using promote_low. This regresses the addressing modes supported for
the extloads not produced by legalization, but that's a fine trade off for now.

Differential Revision: https://reviews.llvm.org/D108496
2021-09-01 10:27:42 -07:00
Heejin Ahn 3419e85b15 [WebAssembly] Free setjmpTable before exiting calls in EmSjLj
This is an improvement over D107852. We don't need to enumerate specific
function names; we can just check for `noreturn` attribute. This also
requires us to make sure `__resumeExeption` and `emscripten_longjmp`
have `noreturn` attribute too; one of them is a JS function and the
other calls a JS function so Clang does not have a way to deduce they
don't return.

This is effectively NFC, because I'm not sure if there is an additional
case this case covers; if we add a custom function call that has
`noreturn` attribute, it will be processed within the SjLj handling and
turned into `__invoke` call. So this really applies to some special
functions like `emscripten_longjmp`.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D108955
2021-08-30 21:46:25 -07:00
Heejin Ahn b8fc71b7ae [WebAssembly] Share rethrowing BBs in LowerEmscriptenEHSjLj
There are three kinds of "rethrowing" BBs in this pass:
1. In Emscripten SjLj, after a possibly longjmping function call, we
   check if the thrown longjmp corresponds to one of setjmps within the
   current function. If not, we rethrow the longjmp by calling
   `emscripten_longjmp`.
2. In Emscripten EH, after a possibly throwing function call, we check
   if the thrown exception corresponds to the current `catch` clauses.
   If not, we rethrow the exception by calling `__resumeException`.
3. When both Emscripten EH and SjLj are used, when we check for an
   exception after a possibly throwing function call, it is possible
   that we get not an exception but a longjmp. In this case, we
   shouldn't swallow it; we should rethrow the longjmp by calling
   `emscripten_longjmp`.
4. When both Emscripten EH and SjLj are used, when we check for a
   longjmp after a possibly longjmping function call, it is possible
   that we get not a longjmp but an exception. In this case, we
   shouldn't swallot it; we should rethrow the exception by calling
   `__resumeException`.

Case 1 is in Emscripten SjLj, 2 is in Emscripten EH, and 3 and 4 are
relevant when both Emscripten EH and SjLj are used. 3 and 4 were first
implemented in D106525.

We create BBs for 1, 3, and 4 in this pass. We create those BBs for
every throwing/longjmping function call, along with other BBs that
contain condition checks. What this CL does is to create a single BB
within a function for each of 1, 3, and 4 cases. These BBs are exiting
BBs in the function and thus don't have successors, so easy to be shared
between calls.

The names of BBs created are:
Case 1: `call.em.longjmp`
Case 3: `rethrow.exn`
Case 4: `rethrow.longjmp`

For the case 2 we don't currently create BBs; we only replace the
existing `resume` instruction with `call @__resumeException`. And Clang
already creates only a single `resume` BB per function and reuses it,
so we don't need to optimize this case.

Not sure what are good benchmarks for EH/SjLj, but this decreases the
size of the object file for `grfmt_jpeg.bc` (presumably from opencv) we
got from one of our users by 8.9%. Even after running `wasm-opt -O4` on
them, there is still 4.8% improvement.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D108945
2021-08-30 21:44:34 -07:00