Commit Graph

917 Commits

Author SHA1 Message Date
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 5694dbccc3 [WebAssembly] support Memory64 in target_features section
Differential Revision: https://reviews.llvm.org/D112266
2021-10-25 09:31:45 -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
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
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
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
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
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
Nikita Popov 90ec6dff86 [OpaquePtr] Forbid mixing typed and opaque pointers
Currently, opaque pointers are supported in two forms: The
-force-opaque-pointers mode, where all pointers are opaque and
typed pointers do not exist. And as a simple ptr type that can
coexist with typed pointers.

This patch removes support for the mixed mode. You either get
typed pointers, or you get opaque pointers, but not both. In the
(current) default mode, using ptr is forbidden. In -opaque-pointers
mode, all pointers are opaque.

The motivation here is that the mixed mode introduces additional
issues that don't exist in fully opaque mode. D105155 is an example
of a design problem. Looking at D109259, it would probably need
additional work to support mixed mode (e.g. to generate GEPs for
typed base but opaque result). Mixed mode will also end up
inserting many casts between i8* and ptr, which would require
significant additional work to consistently avoid.

I don't think the mixed mode is particularly valuable, as it
doesn't align with our end goal. The only thing I've found it to
be moderately useful for is adding some opaque pointer tests in
between typed pointer tests, but I think we can live without that.

Differential Revision: https://reviews.llvm.org/D109290
2021-09-10 15:18:23 +02:00
Fangrui Song fe6dbe7e95 [WebAssembly][test] Fix lower-em-sjlj-indirect-setjmp.ll after D109375 2021-09-08 00:21:30 -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
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
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
Nikita Popov 16086d47c0 [WebAssembly] Fix FastISel of condition in different block (PR51651)
If the icmp is in a different block, then the register for the icmp
operand may not be initialized, as it nominally does not have
cross-block uses. Add a check that the icmp is in the same block
as the branch, which should be the common case.

This matches what X86 FastISel does:
5b6b090cf2/llvm/lib/Target/X86/X86FastISel.cpp (L1648)

The "not" transform that could have a similar issue is dropped
entirely, because it is currently dead: The incoming value is
a branch or select condition of type i1, but this code requires
an i32 to trigger.

Fixes https://bugs.llvm.org/show_bug.cgi?id=51651.

Differential Revision: https://reviews.llvm.org/D108840
2021-08-28 10:28:24 +02:00
Heejin Ahn f5cff292e2 [WebAssembly] Fix PHI when relaying longjmps
When doing Emscritpen EH, if SjLj is also enabled and used and if the
thrown exception has a possiblity being a longjmp instead of an
exception, we shouldn't swallow it; we should rethrow, or relay it. It
was done in D106525 and the code is here:
8441a8eea8/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp (L858-L898)

Here is the pseudocode of that part: (copied from comments)
```
if (%__THREW__.val == 0 || %__THREW__.val == 1)
  goto %tail
else
  goto %longjmp.rethrow

longjmp.rethrow: ;; This is longjmp. Rethrow it
  %__threwValue.val = __threwValue
  emscripten_longjmp(%__THREW__.val, %__threwValue.val);

tail: ;; Nothing happened or an exception is thrown
  ... Continue exception handling ...
```

If the current BB (where the `invoke` is created) has successors that
has the current BB as its PHI incoming node, now that has to change to
`tail` in the pseudocode, because `tail` is the latest BB that is
connected with the next BB, but this was missing.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D108785
2021-08-26 17:25:26 -07:00
Heejin Ahn e849d99df1 [WebAssembly] Use entry block only for initializations in EmSjLj
Emscripten SjLj transformation is done in four steps. This will be
mostly the same for the soon-to-be-added Wasm SjLj; the step 1, 3, and 4
will be shared and there will be separate way of doing step 2.
1. Initialize `setjmpTable` and `setjmpTableSize` in the entry BB
2. Handle `setjmp` callsites
3. Handle `longjmp` callsites
4. Cleanup and update SSA

We initialize `setjmpTable` and `setjmpTableSize` in the entry BB. But
if the entry BB contains a `setjmp` call, some `setjmp` handling
transformation will also happen in the entry BB, such as calling
`saveSetjmp`.

This is fine for Emscripten SjLj but not for Wasm SjLj, because in Wasm
SjLj we will add a dispatch BB that contains a `switch` right after the
entry BB, from which we jump to one of post-`setjmp` BBs. And this
dispatch BB should precede all `setjmp` calls.

Emscripten SjLj (current):
```
entry:
  %setjmpTable = ...
  %setjmpTableSize = ...
  ...
  call @saveSetjmp(...)
```

Wasm SjLj (follow-up):
```
entry:
  %setjmpTable = ...
  %setjmpTableSize = ...

setjmp.dispatch:
  ...
  ; Jump to the right post-setjmp BB, if we are returning from a
  ; longjmp. If this is the first setjmp call, go to %entry.split.
  switch i32 %no, label %entry.split [
    i32 1, label %post.setjmp1
    i32 2, label %post.setjmp2
    ...
    i32 N, label %post.setjmpN
  ]

entry.split:
  ...
  call @saveSetjmp(...)
```

So in Wasm SjLj we split the entry BB to make the entry block only for
`setjmpTable` and `setjmpTableSize` initialization and insert a
`setjmp.dispatch` BB. (This part is not in this CL. This will be a
follow-up.) But note that Emscripten SjLj and Wasm SjLj share all
steps except for the step 2. If we only split the entry BB only for Wasm
SjLj, there will be one more `if`-`else` and the code will be more
complicated.

So this CL splits the entry BB in Emscripten SjLj and put only
initialization stuff there as follows:
Emscripten SjLj (this CL):
```
entry:
  %setjmpTable = ...
  %setjmpTableSize = ...
  br %entry.split

entry.split:
  ...
  call @saveSetjmp(...)
```
This is just done to share code with Wasm SjLj. It adds an unnecessary
branch but this will be removed in later optimization passes anyway.

This is in effect NFC, meaning the program behavior will not change, but
existing ll tests files have changed because the entry block was split.
The reason I upload this in a separate CL is to make the Wasm SjLj diff
tidier, because this changes many existing Emscripten SjLj tests, which
can be confusing for the follow-up Wasm SjLj CL.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D108729
2021-08-25 15:46:57 -07:00
Heejin Ahn c2c9a3fd9c [WebAssembly] Rename wasm.catch.exn intrinsic back to wasm.catch
The plan was to use `wasm.catch.exn` intrinsic to catch exceptions and
add `wasm.catch.longjmp` intrinsic, that returns two values (setjmp
buffer and return value), later to catch longjmps. But because we
decided not to use multivalue support at the moment, we are going to use
one intrinsic that returns a single value for both exceptions and
longjmps. And even if it's not for that, I now think the naming of
`wasm.catch.exn` is a little weird, because the intrinsic can still take
a tag immediate, which means it can be used for anything, not only
exceptions, as long as that returns a single value.

This partially reverts D107405.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D108683
2021-08-25 14:19:22 -07:00
Heejin Ahn d5244fb160 [WebAssembly] Use SSAUpdaterBulk in LowerEmscriptenSjLj
We update SSA in two steps in Emscripten SjLj:
1. Rewrite uses of `setjmpTable` and `setjmpTableSize` variables and
   place `phi`s where necessary, which are updated where we call
   `saveSetjmp`.
2. Do a whole function level SSA update for all variables, because we
   split BBs where `setjmp` is called and there are possibly variable
   uses that are not dominated by a def.
   (See 955b91c19c/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp (L1314-L1324))

We have been using `SSAUpdater` to do this, but `SSAUpdaterBulk` class
was added after this pass was first created, and for the step 2 it looks
like a better alternative with a possible performance benefit. Not sure
the author is aware of it, but `SSAUpdaterBulk` seems to have a
limitation: it cannot handle a use within the same BB as a def but
before it. For example:
```
... = %a + 1
%a = foo();
```
or
```
%a = %a + 1
```
The uses `%a` in RHS should be rewritten with another SSA variable of
`%a`, most likely one generated from a `phi`. But `SSAUpdaterBulk`
thinks all uses of `%a` are below the def of `%a` within the same BB.
(`SSAUpdater` has two different functions of rewriting because of this:
`RewriteUse` and `RewriteUseAfterInsertions`.) This doesn't affect our
usage in the step 2 because that deals with possibly non-dominated uses
by defs after block splitting. But it does in the step 1, which still
uses `SSAUpdater`.

But this CL also simplifies the step 1 by using `make_early_inc_range`,
removing the need to advance the iterator before rewriting a use.

This is NFC; the test changes are just the order of PHI nodes.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D108583
2021-08-24 18:23:51 -07:00
Heejin Ahn 77b921b870 [WebAssembly] Tidy up EH/SjLj options
This CL is small, but the description can be a little long because I'm
trying to sum up the status quo for Emscripten/Wasm EH/SjLj options.

First, this CL adds an option for Wasm SjLj (`-wasm-enable-sjlj`), which
handles SjLj using Wasm EH. The implementation for this will be added as
a followup CL, but this adds the option first to do error checking.

This also adds an option for Wasm EH (`-wasm-enable-eh`), which has been
already implemented. Before we used `-exception-model=wasm` as the same
meaning as enabling Wasm EH, but after we add Wasm SjLj, it will be
possible to use Wasm EH instructions for Wasm SjLj while not enabling
EH, so going forward, to use Wasm EH, `opt` and `llc` will need this
option. This only affects `opt` and `llc` command lines and does not
affect Emscripten user interface.

Now we have two modes of EH (Emscripten/Wasm) and also two modes of SjLj
(also Emscripten/Wasm). The options corresponding to each of are:
- Emscripten EH: `-enable-emscripten-cxx-exceptions`
- Emscripten SjLj: `-enable-emscripten-sjlj`
- Wasm EH: `-wasm-enable-eh -exception-model=wasm`
           `-mattr=+exception-handling`
- Wasm SjLj: `-wasm-enable-sjlj -exception-model=wasm`
             `-mattr=+exception-handling`
The reason Wasm EH/SjLj's options are a little complicated are
`-exception-model` and `-mattr` are common LLVM options ane not under
our control. (`-mattr` can be omitted if it is embedded within the
bitcode file.)

And we have the following rules of the option composition:
- Emscripten EH and Wasm EH cannot be turned on at the same itme
- Emscripten SjLj and Wasm SjLj cannot be turned on at the same time
- Wasm SjLj should be used with Wasm EH

Which means we now allow these combinations:
- Emscripten EH + Emscripten SjLj: the current default in `emcc`
- Wasm EH + Emscripten SjLj:
  This is allowed, but only as an interim step in which we are testing
  Wasm EH but not yet have a working implementation of Wasm SjLj. This
  will error out (D107687) in compile time if `setjmp` is called in a
  function in which Wasm exception is used.
- Wasm EH + Wasm SjLj:
  This will be the default mode later when using Wasm EH. Currently Wasm
  SjLj implementation doesn't exist, so it doesn't work.
- Emscripten EH + Wasm SjLj will not work.

This CL moves these error checking routines to
`WebAssemblyPassConfig::addIRPasses`. Not sure if this is an ideal place
to do this, but I couldn't find elsewhere. Currently some checking is
done within LowerEmscriptenEHSjLj, but these checks only run if
LowerEmscriptenEHSjLj runs so it may not run when Wasm EH is used. This
moves that to `addIRPasses` and adds some more checks.

Currently LowerEmscriptenEHSjLj pass is responsible for Emscripten EH
and Emscripten SjLj. Wasm EH transformations are done in multiple
places, including WasmEHPrepare, LateEHPrepare, and CFGStackify. But in
the followup CL, LowerEmscriptenEHSjLj pass will be also responsible for
a part of Wasm SjLj transformation, because WasmSjLj will also be using
several Emscripten library functions, and we will be sharing more than
half of the transformation to do that between Emscripten SjLj and Wasm
SjLj.

Currently we have `-enable-emscripten-cxx-exceptions` and
`-enable-emscripten-sjlj` but these only work for `llc`, because for
`llc` we feed these options to the pass but when we run the pass using
`opt` the pass will be created with no options and the default options
will be used, which turns both Emscripten EH and Emscripten SjLj on.

Now we have one more SjLj option to care for, LowerEmscriptenEHSjLj pass
needs a finer way to control these options. This CL removes those
default parameters and make LowerEmscriptenEHSjLj pass read directly
from command line options specified. So if we only run
`opt -wasm-lower-em-ehsjlj`, currently both Emscripten EH and Emscripten
SjLj will run, but with this CL, none will run unless we additionally
pass `-enable-emscripten-cxx-exceptions` or `-enable-emscripten-sjlj`,
or both. This does not affect users; this only affects our `opt` tests
because `emcc` will not call either `opt` or `llc`. As a result of this,
our existing Emscripten EH/SjLj tests gained one or both of those
options in their `RUN` lines.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D107685
2021-08-24 17:54:39 -07:00
Thomas Lively ca541aa319 [WebAssembly] Fix up out-of-range BUILD_VECTOR lane constants
Fixes PR51605 in which a DAG combine and legalization sequence generated
out-of-range constants in BUILD_VECTOR lanes. In the v16i8 case, the constants
were 255, which would be in range if DAG ISel used unsigned constants, but it is
out of range because DAG ISel uses signed constants.

Differential Revision: https://reviews.llvm.org/D108669
2021-08-24 17:24:03 -07:00
Thomas Lively 88962cea46 [WebAssembly] Restore builtins and intrinsics for pmin/pmax
Partially reverts 85157c0079, which had removed these builtins and intrinsics
in favor of normal codegen patterns. It turns out that it is possible for the
patterns to be split over multiple basic blocks, however, which means that DAG
ISel is not able to select them to the pmin/pmax instructions. To make sure the
SIMD intrinsics generate the correct instructions in these cases, reintroduce
the clang builtins and corresponding LLVM intrinsics, but also keep the normal
pattern matching as well.

Differential Revision: https://reviews.llvm.org/D108387
2021-08-20 09:21:31 -07:00
Thomas Lively fd0557dbf1 [WebAssembly] More convert_low and promote_low codegen
The convert_low and promote_low instructions can widen the lower two lanes of a
four-lane vector, but we were previously scalarizing patterns that widened lanes
besides the low two lanes. The commit adds a shuffle to move the widened lanes
into the low lane positions so the convert_low and promote_low instructions can
be used instead of scalarizing.

Depends on D108266.

Differential Revision: https://reviews.llvm.org/D108341
2021-08-19 15:37:12 -07:00
Thomas Lively b311a040ef [WebAssembly] Pattern match SIMD convert_low and promote_low during ISel
Since the simplest DAG patterns for convert_low and promote_low instructions
involved v2i32, v2f32, v4i64, and v4f64 types, which are not legal in the
WebAssembly backend and would be eliminated by type legalization, we were
previously matching those patterns in a DAG combine before the type legalization
stage. However in cases where the vectors were wider than 128 bits, the patterns
we matched were not created until the type legalization stage when the wide
vectors were split up. Type legalization would continue to eliminate the illegal
types we were matching as well, so the code ended up scalarized.

To make the ISel for these instructions more robust, match the scalarized
patterns rather than the patterns containing illegal types. Add tests with
double-wide vectors to show that this works as intended.

Fixes PR51098.
Depends on D107502.

Differential Revision: https://reviews.llvm.org/D108266
2021-08-19 15:24:28 -07:00
Thomas Lively b69374ca58 [WebAssembly] Legalize vector types by widening
The default legalization of unsupported vector types is to promote the integers
in each lane, which leads to extra sign or zero extending and masking when
moving data into and out of vectors. Switch our preferred type legalization from
the default to vector widening, which keeps the data in the low lanes of the
vector rather than in the low bits of each lane. The unused high lanes can be
ignored.

Half-wide vectors are now loaded from memory into the low 64 bits of the v128
rather than spread out among the lanes. As a result, v128.load64_splat is a much
more common operation, so add new patterns to support it.

Differential Revision: https://reviews.llvm.org/D107502
2021-08-19 12:07:33 -07:00
Thomas Lively 4ade3af133 [WebAssembly] Autogenerate checks for simd-conversions.ll
In preparation for adding more tests more simply.

Differential Revision: https://reviews.llvm.org/D108264
2021-08-17 21:35:23 -07:00
Heejin Ahn adb96d2e76 [WebAssembly] Fix leak in Emscripten SjLj
For SjLj, we allocate a table to record setjmp buffer info in the entry
of each setjmp-calling function by inserting a `malloc` call, and insert
a `free` call to free the buffer before each `ret` instruction.

But this is not sufficient; we have to free the buffer before we throw.
In SjLj handling, normal functions that can possibly throw or longjmp
are wrapped with an invoke and caught within the function so they don't
end up escaping the function. But three functions throw and escape the
function:
- `__resumeException` (Emscripten library function used for Emscripten
  EH)
- `emscripten_longjmp` (Emscripten library function used for Emscripten
  SjLj)
- `__cxa_throw` (libc++abi function called when for C++ `throw` keyword)

The first two functions are used to rethrow the current
exception/longjmp when the caught exception/longjmp is not for the
current function. `__cxa_throw` is used for exception, and because we
consider that a function that cannot longjmp, it escapes the function
right away, before which we should free the buffer.

Currently `lsan.test_longjmp3` and `lsan.test_exceptions_longjmp3` fail
in Emscripten; this CL fixes these.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D107852
2021-08-12 16:32:46 -07:00
Heejin Ahn aca198cf74 [WebAssembly] Error out when Emscripten SjLj setjmp is used with Wasm EH
Currently, when Wasm EH is used with Emscripten SjLj, Emscripten SjLj
cannot handle `invoke` instructions - it assumes all `invoke`s have been
lowered away with Emscripten EH. But in Wasm EH they are lowered in
instruction selection, so they are still present in the IR stage. This
happens when
1. Wasm EH and Emscripten SjLj are used together
2. A function that calls `setjmp` uses exceptions, i.e., has `invoke`s

We were already erroring out with an assertion failure in this case, but
this CL makes it error out more properly with a valid error message.

Wasm EH + Wasm SjLj will not have this restrictions. (it will have
another restriction though, e.g., `setjmp` cannot be called within
`catch`. But why would anyone do that..)

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D107687
2021-08-12 16:19:04 -07:00
Heejin Ahn 78e87970af [WebAssembly] Disable offset folding for function addresses
Wasm does not support function addresses with offsets, but isel can
generate folded SDValues in the form of (@func + offset) without this
patch.

Fixes https://bugs.llvm.org/show_bug.cgi?id=43133.

Reviewed By: dschuff, sbc100

Differential Revision: https://reviews.llvm.org/D107940
2021-08-12 13:40:41 -07:00
Heejin Ahn 41ba39dfcd [WebAssembly] Don't do SjLj transformation when there's only setjmp
When there is a `setjmp` call in a function, we transform every callsite
of `setjmp` to record its information by calling `saveSetjmp` function,
and we also transform every callsite of a function that can longjmp to
to check if a longjmp occurred and if so jump to the corresponding
post-setjmp BB. Currently we are doing this for every function that
contains a call to `setjmp`, but if there is no other function call
within that function that can longjmp, this transformation of `setjmp`
callsite and all the preparation of `setjmpTable` in the entry of the
function are not necessary.

This checks if a setjmp-calling function has any other calls that can
longjmp, and if not, skips the function for the SjLj transformation.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D107530
2021-08-05 15:28:02 -07:00
Heejin Ahn 9c3345ad10 [WebAssembly] Cleanup Emscripten SjLj tests
- Remove a redundant test: there were `longjmp_only` and `only_longjmp`,
  which do the same thing
- Add `CHECK-LABEL` lines for function names

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D107511
2021-08-04 21:16:08 -07:00
Heejin Ahn 9bd02c433b [WebAssembly] Misc. cosmetic changes in EH (NFC)
- Rename `wasm.catch` intrinsic to `wasm.catch.exn`, because we are
  planning to add a separate `wasm.catch.longjmp` intrinsic which
  returns two values.
- Rename several variables
- Remove an unnecessary parameter from `canLongjmp` and `isEmAsmCall`
  from LowerEmscriptenEHSjLj pass
- Add `-verify-machineinstrs` in a test for a safety measure
- Add more comments + fix some errors in comments
- Replace `std::vector` with `SmallVector` for cases likely with small
  number of elements
- Renamed `EnableEH`/`EnableSjLj` to `EnableEmEH`/`EnableEmSjLj`: We are
  soon going to add `EnableWasmSjLj`, so this makes the distincion
  clearer

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D107405
2021-08-03 21:03:46 -07:00
Paulo Matos d3a0a65bf0 Reland: "[WebAssembly] Add new pass to lower int/ptr conversions of reftypes"
Add new pass LowerRefTypesIntPtrConv to generate debugtrap
instruction for an inttoptr and ptrtoint of a reference type instead
of erroring, since calling these instructions on non-integral pointers
has been since allowed (see ac81cb7e6).

Differential Revision: https://reviews.llvm.org/D107102
2021-08-03 09:20:51 +02:00
Paulo Matos 245f2ee647 Revert "[WebAssembly] Add new pass to lower int/ptr conversions of reftypes"
This reverts commit ce1c59dea6.
2021-08-02 20:12:25 +02:00
Paulo Matos ce1c59dea6 [WebAssembly] Add new pass to lower int/ptr conversions of reftypes
Add new pass LowerRefTypesIntPtrConv to generate trap
instruction for an inttoptr and ptrtoint of a reference type instead
of erroring, since calling these instructions on non-integral pointers
has been since allowed (see ac81cb7e6).

Differential Revision: https://reviews.llvm.org/D107102
2021-08-02 19:40:00 +02:00
Thomas Lively 417e500668 [WebAssembly] Compute known bits for SIMD bitmask intrinsics
This optimizes out the mask when the result of a bitmask is interpreted as an i8
or i16 value. Resolves PR50507.

Differential Revision: https://reviews.llvm.org/D107103
2021-08-02 09:52:34 -07:00
Thomas Lively 33786576fd [WebAssembly] Codegen for extmul SIMD instructions
Replace the clang builtins and LLVM intrinsics for the SIMD extmul instructions
with normal codegen patterns.

Differential Revision: https://reviews.llvm.org/D106724
2021-07-27 08:41:30 -07:00
Heejin Ahn c285a11efd [WebAssembly] Make Emscripten EH work with Emscripten SjLj
When Emscripten EH mixes with Emscripten SjLj, we are not currently
handling some of them correctly. There are three cases:
1. The current function calls `setjmp` and there is an `invoke` to a
   function that can either throw or longjmp. In this case, we have to
   check both for exception and longjmp. We are currently handling this
   case correctly:
   0c0eb76782/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp (L1058-L1090)
   When inserting routines for functions that can longjmp, which we do
   only for setjmp-calling functions, we check if the function was
   previously an `invoke` and handle it correctly.

2. The current function does NOT call `setjmp` and there is an `invoke`
   to a function that can either throw or longjmp. Because there is no
   `setjmp` call, we haven't been doing any check for functions that can
   longjmp. But in that case, for `invoke`, we only check for an
   exception and if it is not an exception we reset `__THREW__` to 0,
   which can silently swallow the longjmp:
   0c0eb76782/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp (L70-L80)
   This CL fixes this.

3. The current function calls `setjmp` and there is no `invoke`. Because
   it is not an `invoke`, we haven't been doing any check for functions
   that can throw, and only insert longjmp-checking routines for
   functions that can longjmp. But in that case, if a longjmpable
   function throws, we only check for a longjmp so if it is not a
   longjmp we reset `__THREW__` to 0, which can silently swallow the
   exception:
   0c0eb76782/llvm/lib/Target/WebAssembly/WebAssemblyLowerEmscriptenEHSjLj.cpp (L156-L169)
   This CL fixes this.

To do that, this moves around some code, so we register necessary
functions for both EH and SjLj and precompute some data (the set of
functions that contains `setjmp`) before doing actual EH or SjLj
transformation.

This CL makes 2nd and 3rd tests in
https://github.com/emscripten-core/emscripten/pull/14732 work.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D106525
2021-07-26 13:48:31 -07:00
Thomas Lively 85157c0079 [WebAssembly] Codegen for pmin and pmax
Replace the clang builtins and LLVM intrinsics for {f32x4,f64x2}.{pmin,pmax}
with standard codegen patterns. Since wasm_simd128.h uses an integer vector as
the standard single vector type, the IR for the pmin and pmax intrinsic
functions contains bitcasts that would not be there otherwise. Add extra codegen
patterns that can still select the pmin and pmax instructions in the presence of
these bitcasts.

Differential Revision: https://reviews.llvm.org/D106612
2021-07-23 14:49:21 -07:00
Paulo Matos 46667a1003 [WebAssembly] Implementation of global.get/set for reftypes in LLVM IR
Reland of 31859f896.

This change implements new DAG notes GLOBAL_GET/GLOBAL_SET, and
lowering methods for load and stores of reference types from IR
globals. Once the lowering creates the new nodes, tablegen pattern
matches those and converts them to Wasm global.get/set.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D104797
2021-07-22 22:07:24 +02:00
Thomas Lively 8af333cf1a [WebAssembly] Replace @llvm.wasm.popcnt with @llvm.ctpop.v16i8
Use the standard target-independent intrinsic to take advantage of standard
optimizations.

Differential Revision: https://reviews.llvm.org/D106506
2021-07-21 16:45:54 -07:00