Commit Graph

87 Commits

Author SHA1 Message Date
Heejin Ahn 31a71a393f [WebAssembly] Make result of 'catch' inst variadic
`catch` instruction can have any number of result values depending on
its tag, but so far we have only needed a single i32 return value for
C++ exception so the instruction was specified that way. But using the
instruction for SjLj handling requires multiple return values.

This makes `catch` instruction's results variadic and moves selection of
`throw` and `catch` instruction from ISelLowering to ISelDAGToDAG.
Moving `catch` to ISelDAGToDAG is necessary because I am not aware of
a good way to do instruction selection for variadic output instructions
in TableGen. This also moves `throw` because 1. `throw` and `catch`
share the same utility function and 2. there is really no reason we
should do that in ISelLowering in the first place. What we do is mostly
the same in both places, and moving them to ISelDAGToDAG allows us to
remove unnecessary mid-level nodes for `throw` and `catch` in
WebAssemblyISD.def and WebAssemblyInstrInfo.td.

This also adds handling for new `catch` instruction to AsmTypeCheck.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D107423
2021-08-04 14:05:33 -07:00
Heejin Ahn 1d891d44f3 [WebAssembly] Rename event to tag
We recently decided to change 'event' to 'tag', and 'event section' to
'tag section', out of the rationale that the section contains a
generalized tag that references a type, which may be used for something
other than exceptions, and the name 'event' can be confusing in the web
context.

See
- https://github.com/WebAssembly/exception-handling/issues/159#issuecomment-857910130
- https://github.com/WebAssembly/exception-handling/pull/161

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D104423
2021-06-17 20:34:19 -07:00
Sam Parker 92e7771483 [WebAssembly] Invert branch condition on xor input
A frequent pattern for floating point conditional branches use an xor
to invert the input for the branch. Instead we can fold away the xor
by swapping the branch target instead.

Differential Revision: https://reviews.llvm.org/D99171
2021-04-01 09:23:28 +01:00
Heejin Ahn 7c594bab00 [WebAssembly] Change catch_all's opcode
We decided to change `catch_all`'s opcode from 0x05, which is the same
as `else`, to 0x19, to avoid some complicated handling in the tools.

See: https://github.com/WebAssembly/exception-handling/issues/147

Reviewed By: sbc100

Differential Revision: https://reviews.llvm.org/D96863
2021-02-17 10:16:23 -08:00
Heejin Ahn 35f5f797a6 [WebAssemblly] Fix rethrow's argument computation
Previously we assumed `rethrow`'s argument was always 0, but it turned
out `rethrow` follows the same rule with `br` or `delegate`:
https://github.com/WebAssembly/exception-handling/pull/137
https://github.com/WebAssembly/exception-handling/issues/146#issuecomment-777349038

Currently `rethrow`s generated by our backend always rethrow the
exception caught by the innermost enclosing catch, so this adds a
function to compute that and replaces `rethrow`'s argument with its
computed result.

This also renames `EHPadStack` in `InstPrinter` to `TryStack`, because
in CFGStackify we use `EHPadStack` to mean the range between
`catch`~`end`, while in `InstPrinter` we used it to mean the range
between `try`~`catch`, so choosing different names would look clearer.
Doesn't contain any functional changes in `InstPrinter`.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D96595
2021-02-13 03:43:15 -08:00
Heejin Ahn ed41945faa [WebAssembly] Fix call unwind mismatches
This adds `delegate` instruction and use it to fix unwind destination
mismatches created by marker placement in CFGStackify.

There are two kinds of unwind destination mismatches:
- Mismatches caused by throwing instructions (here we call it "call
  unwind mismatches", even though `throw` and `rethrow` can also cause
  mismatches)
- Mismatches caused by `catch`es, in case a foreign exception is not
  caught by the nearest `catch` and the next outer `catch` is not the
  catch it should unwind to. This kind of mismatches didn't exist in the
  previous version of the spec, because in the previous spec `catch` was
  effectively `catch_all`, catching all exceptions.

This implements routines to fix the first kind of unwind mismatches,
which we call "call unwind mismatches". The second mismatch (catch
unwind mismatches) will be fixed in a later CL.

This also reenables all previously disabled tests in cfg-stackify-eh.ll
and updates FileCheck lines to match the new spec. Two tests were
deleted because they specifically tested the way we fixed unwind
mismatches before using `exnref`s and branches, which we don't do
anymore.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D94048
2021-02-06 07:07:04 -08:00
Heejin Ahn 52e240a072 [WebAssembly] Remove exnref and br_on_exn
This removes `exnref` type and `br_on_exn` instruction. This is
effectively NFC because most uses of these were already removed in the
previous CLs.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D94041
2021-01-09 02:02:54 -08:00
Heejin Ahn 9e4eadeb13 [WebAssembly] Update basic EH instructions for the new spec
This implements basic instructions for the new spec.

- Adds new versions of instructions: `catch`, `catch_all`, and `rethrow`
- Adds support for instruction selection for the new instructions
 - `catch` needs a custom routine for the same reason `throw` needs one,
   to encode `__cpp_exception` tag symbol.
- Updates `WebAssembly::isCatch` utility function to include `catch_all`
  and Change code that compares an instruction's opcode with `catch` to
  use that function.
- LateEHPrepare
  - Previously in LateEHPrepare we added `catch` instruction to both
    `catchpad`s (for user catches) and `cleanuppad`s (for destructors).
    In the new version `catch` is generated from `llvm.catch` intrinsic
    in instruction selection phase, so we only need to add `catch_all`
    to the beginning of cleanup pads.
  - `catch` is generated from instruction selection, but we need to
    hoist the `catch` instruction to the beginning of every EH pad,
    because `catch` can be in the middle of the EH pad or even in a
    split BB from it after various code transformations.
  - Removes `addExceptionExtraction` function, which was used to
    generate `br_on_exn` before.
- CFGStackfiy: Deletes `fixUnwindMismatches` function. Running this
  function on the new instruction causes crashes, and the new version
  will be added in a later CL, whose contents will be completely
  different. So deleting the whole function will make the diff easier to
  read.
- Reenables all disabled tests in exception.ll and eh-lsda.ll and a
  single basic test in cfg-stackify-eh.ll.
- Updates existing tests to use the new assembly format. And deletes
  `br_on_exn` instructions from the tests and FileCheck lines.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D94040
2021-01-09 01:48:06 -08:00
Heejin Ahn 9724c3cff4 [WebAssembly] Update WasmEHPrepare for the new spec
Clang generates `wasm.get.exception` and `wasm.get.ehselector`
intrinsics, which respectively return a caught exception value (a
pointer to some C++ exception struct) and a selector (an integer value
that tells which C++ `catch` clause the current exception matches, or
does not match any).

WasmEHPrepare is a pass that does some IR-level preparation before
instruction selection. Previously one of things we did in this pass was
to convert `wasm.get.exception` intrinsic calls to
`wasm.extract.exception` intrinsics. Their semantics were the same
except `wasm.extract.exception` did not have a token argument. We
maintained these two separate intrinsics with the same semantics because
instruction selection couldn't handle token arguments. This
`wasm.extract.exception` intrinsic was later converted to
`extract_exception` instruction in instruction selection, which was a
pseudo instruction to implement `br_on_exn`. Because `br_on_exn` pushed
an extracted value onto the value stack after the `end` instruction of a
`block`, but LLVM does not have a way of modeling that kind of behavior,
so this pseudo instruction was used to pull an extracted value out of
thin air, like this:
```
block $l0
  ...
  br_on_exn $cpp_exception $l0
  ...
end
extract_exception ;; pushes values onto the stack
```

In the new spec, we don't need this pseudo instruction anymore because
`catch` itself returns a value and we don't have `br_on_exn` anymore. In
the spec `catch` returns multiple values (like `br_on_exn`), but here we
assume it only returns a single i32, which is sufficient to support C++.

So this renames `wasm.get.exception` intrinsic to `wasm.catch`. Because
this CL does not yet contain instruction selection for `wasm.catch`
intrinsic, all `RUN` lines in exception.ll, eh-lsda.ll, and
cfg-stackify-eh.ll, and a single `RUN` line in wasm-eh.cpp (which is an
end-to-end test from C++ source to assembly) fail. So this CL
temporarily disables those `RUN` lines, and for those test files without
any valid remaining `RUN` lines, adds a dummy `RUN` line to make them
pass. These tests will be reenabled in later CLs.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D94039
2021-01-08 23:38:26 -08:00
Heejin Ahn 7be271537e [WebAssembly] Rename wasm_rethrow_in_catch intrinsic/builtin
`wasm_rethrow_in_catch` intrinsic and builtin are used in order to
rethrow an exception when the exception is caught but there is no
matching clause within the current `catch`. For example,
```
try {
  foo();
} catch (int n) {
  ...
}
```
If the caught exception does not correspond to C++ `int` type, it should
be rethrown. These intrinsic/builtin were renamed `rethrow_in_catch`
because at the time I thought there would be another intrinsic for C++'s
`throw` keyword, which rethrows an exception. It turned out that `throw`
keyword doesn't require wasm's `rethrow` instruction, so we rename
`rethrow_in_catch` to just `rethrow` here.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D94038
2021-01-08 06:55:04 -08:00
Dominic Chen 4252f3009b
[WebAssembly] Set unreachable as canonical to permit disassembly
Currently, using llvm-objdump to disassemble a function containing
unreachable will trigger an assertion while decoding the opcode, since both
unreachable and debug_unreachable have the same encoding. To avoid this, set
unreachable as the canonical decoding.

Differential Revision: https://reviews.llvm.org/D87431
2020-09-10 15:04:16 -04:00
Thomas Lively c5d012341e [WebAssembly] Make BR_TABLE non-duplicable
Summary:
After their range checks were removed in 7f50c15be5, br_tables
started being duplicated into their predecessors by tail
folding. Unfortunately, when the br_tables were in loops this
transformation introduced bad irreducible control flow which was later
expanded into even more br_tables. This commit abuses the
`isNotDuplicable` property to prevent this irreducible control flow
from being introduced. This change saves a few dozen bytes of code
size and has a negligible affect on performance for most of the large
Emscripten benchmarks, but can improve performance significantly on
microbenchmarks of switches in loops.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D81628
2020-06-11 15:11:45 -07:00
Thomas Lively a07c08f74f [WebAssembly] Lower llvm.debugtrap properly
Summary:
Unlike normal traps, debug traps are allowed to return and can have
additional instructions in the same basic block. Without explicit
backend support for debug traps, they are lowered in ISel as normal
traps. Since normal traps are lowered in the WebAssembly backend to
the UNREACHABLE instruction, which is a terminator, using debug traps
could lead to invalid MBBs when there are additional instructions
after the trap. This patch fixes the issue by lowering debug traps to
a new version of the UNREACHABLE instruction, DEBUG_UNREACHABLE, that
is not a terminator.

An alternative approach would have been to make UNREACHABLE not a
terminator, but that breaks a large number of tests. In particular, it
would require removing the traps inserted after noreturn calls to
@llvm.wasm.throw because otherwise the terminator throw would be
followed by a non-terminator UNREACHABLE and we would be back to
having invalid MBBs. Overall the approach in this patch seems simpler.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D81055
2020-06-04 13:25:10 -07:00
Thomas Lively 00f9e5aa76 [WebAssembly] Make returns variadic
Summary:
This is necessary and sufficient to get simple cases of multiple
return working with multivalue enabled. More complex cases will
require block and loop signatures to be generalized to potentially be
type indices as well.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68684

llvm-svn: 374235
2019-10-09 21:42:08 +00:00
Heejin Ahn 9f96a58ccc [WebAssembly] Rename except_ref type to exnref
Summary:
We agreed to rename `except_ref` to `exnref` for consistency with other
reference types in
https://github.com/WebAssembly/exception-handling/issues/79. This also
renames WebAssemblyInstrExceptRef.td to WebAssemblyInstrRef.td in order
to use the file for other reference types in future.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, jfb, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64703

llvm-svn: 366145
2019-07-15 22:49:25 +00:00
Heejin Ahn 66ce419468 [WebAssembly] Make rethrow take an except_ref type argument
Summary:
In the new wasm EH proposal, `rethrow` takes an `except_ref` argument.
This change was missing in r352598.

This patch adds `llvm.wasm.rethrow.in.catch` intrinsic. This is an
intrinsic that's gonna eventually be lowered to wasm `rethrow`
instruction, but this intrinsic can appear only within a catchpad or a
cleanuppad scope. Also this intrinsic needs to be invokable - otherwise
EH pad successor for it will not be correctly generated in clang.

This also adds lowering logic for this intrinsic in
`SelectionDAGBuilder::visitInvoke`. This routine is basically a
specialized and simplified version of
`SelectionDAGBuilder::visitTargetIntrinsic`, but we can't use it
because if is only for `CallInst`s.

This deletes the previous `llvm.wasm.rethrow` intrinsic and related
tests, which was meant to be used within a `__cxa_rethrow` library
function. Turned out this needs some more logic, so the intrinsic for
this purpose will be added later.

LateEHPrepare takes a result value of `catch` and inserts it into
matching `rethrow` as an argument.

`RETHROW_IN_CATCH` is a pseudo instruction that serves as a link between
`llvm.wasm.rethrow.in.catch` and the real wasm `rethrow` instruction. To
generate a `rethrow` instruction, we need an `except_ref` argument,
which is generated from `catch` instruction. But `catch` instrutions are
added in LateEHPrepare pass, so we use `RETHROW_IN_CATCH`, which takes
no argument, until we are able to correctly lower it to `rethrow` in
LateEHPrepare.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59352

llvm-svn: 356316
2019-03-16 05:38:57 +00:00
Heejin Ahn 4367587fc6 [WebAssembly] Tidy up `let` statements in .td files (NFC)
Summary:
- Delete {} for one-line `let` statements
- Don't indent within `let` blocks
- Add comments after `let` block's closing braces

Reviewers: tlively

Subscribers: dschuff, sbc100, jgravelle-google, sunfish, jfb, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57730

llvm-svn: 353248
2019-02-06 00:17:03 +00:00
Wouter van Oortmerssen 1a91cb0402 [WebAssembly] Make disassembler always emit most canonical name.
Summary:
There are a few instructions that all map to the same opcode, so
when disassembling, we have to pick one. That was just the first one
before (the except_ref variant in the case of "call"), now it is the
one marked as IsCanonical in tablegen, or failing that, the shortest
name (which is typically the "canonical" one).

Also introduced a canonical "end" instruction for this purpose.

Reviewers: dschuff, tlively

Subscribers: sbc100, jgravelle-google, aheejin, llvm-commits, sunfish

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57713

llvm-svn: 353131
2019-02-05 01:19:45 +00:00
Heejin Ahn d6f487863d [WebAssembly] Exception handling: Switch to the new proposal
Summary:
This switches the EH implementation to the new proposal:
https://github.com/WebAssembly/exception-handling/blob/master/proposals/Exceptions.md
(The previous proposal was
 https://github.com/WebAssembly/exception-handling/blob/master/proposals/old/Exceptions.md)

- Instruction changes
  - Now we have one single `catch` instruction that returns a except_ref
    value
  - `throw` now can take variable number of operations
  - `rethrow` does not have 'depth' argument anymore
  - `br_on_exn` queries an except_ref to see if it matches the tag and
    branches to the given label if true.
  - `extract_exception` is a pseudo instruction that simulates popping
    values from wasm stack. This is to make `br_on_exn`, a very special
    instruction, work: `br_on_exn` puts values onto the stack only if it
    is taken, and the # of values can vay depending on the tag.

- Now there's only one `catch` per `try`, this patch removes all special
  handling for terminate pad with a call to `__clang_call_terminate`.
  Before it was the only case there are two catch clauses (a normal
  `catch` and `catch_all` per `try`).

- Make `rethrow` act as a terminator like `throw`. This splits BB after
  `rethrow` in WasmEHPrepare, and deletes an unnecessary `unreachable`
  after `rethrow` in LateEHPrepare.

- Now we stop at all catchpads (because we add wasm `catch` instruction
  that catches all exceptions), this creates new
  `findWasmUnwindDestinations` function in SelectionDAGBuilder.

- Now we use `br_on_exn` instrution to figure out if an except_ref
  matches the current tag or not, LateEHPrepare generates this sequence
  for catch pads:
```
  catch
  block i32
  br_on_exn $__cpp_exception
  end_block
  extract_exception
```

- Branch analysis for `br_on_exn` in WebAssemblyInstrInfo

- Other various misc. changes to switch to the new proposal.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D57134

llvm-svn: 352598
2019-01-30 03:21:57 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Heejin Ahn 8e2bac8e7f [WebAssembly] Use 'I' multiclass template for br_table (NFC)
Summary:
We don't need to explicitly use `NI` anymore because we now don't use
`let` statements within the definitions.

Reviewers: aardappel

Subscribers: dschuff, sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D56376

llvm-svn: 350594
2019-01-08 01:15:15 +00:00
Wouter van Oortmerssen 820c6263d9 [WebAssembly] Fixed disassembler not knowing about new brlist operand
Summary:
The previously introduced new operand type for br_table didn't have
a disassembler implementation, causing an assert.

Reviewers: dschuff, aheejin

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D56227

llvm-svn: 350366
2019-01-03 23:01:30 +00:00
Wouter van Oortmerssen f227621036 [WebAssembly] Added basic support for if/else/end_if in MC layer.
Summary:
These instructions are currently unused in our backend, but for
completeness it is good to support them, so they can be used with
the assembler in hand-written code.

Tests are very basic, signature support missing much like other blocks.

Reviewers: dschuff, aheejin

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D55973

llvm-svn: 350079
2018-12-26 22:55:26 +00:00
Wouter van Oortmerssen d3c544aa6e [WebAssembly] Fix assembler parsing of br_table.
Summary:
We use `variable_ops` in the tablegen defs to denote the list of
branch targets in `br_table`, but unlike other uses of `variable_ops`
(e.g. call) the these branch targets need to actually be encoded in the
instruction. The existing tables for `variable_ops` cause not operands
to be accepted by the assembly matcher.

Following the example of ARM:
2cc0a7da87/lib/Target/ARM/ARMInstrInfo.td (L550-L555)
we introduce a new operand type to capture this list, and we use the
same {} syntax as ARM as well to differentiate them from regular
integer operands.

Also removed definition and use of TSFlags in tablegen defs, since
`br_table` now has a non-variable_ops immediate operand, so the
previous logic of only the variable_ops arguments being labels didn't
make sense anymore.

Reviewers: dschuff, aheejin, sunfish

Subscribers: javed.absar, sbc100, jgravelle-google, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D55401

llvm-svn: 349405
2018-12-17 22:04:44 +00:00
Heejin Ahn da419bdb5e [WebAssembly] Add support for the event section
Summary:
This adds support for the 'event section' specified in the exception
handling proposal. (This was named 'exception section' first, but later
renamed to 'event section' to take possibilities of other kinds of
events into consideration. But currently we only store exception info in
this section.)

The event section is added between the global section and the export
section. This is for ease of validation per request of the V8 team.

This patch:
- Creates the event symbol type, which is a weak symbol
- Makes 'throw' instruction take the event symbol '__cpp_exception'
- Adds relocation support for events
- Adds WasmObjectWriter / WasmObjectFile (Reader) support
- Adds obj2yaml / yaml2obj support
- Adds '.eventtype' printing support

Reviewers: dschuff, sbc100, aardappel

Subscribers: jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D54096

llvm-svn: 346825
2018-11-14 02:46:21 +00:00
Heejin Ahn a40303aa03 [WebAssembly] Fix assembly printing of br_table
Summary: In `br_table's stack version asm string, \t was missing.

Reviewers: aardappel

Subscribers: dschuff, sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53516

llvm-svn: 344981
2018-10-23 00:28:14 +00:00
Thomas Lively c63b5fcb2a [WebAssembly][NFC] Remove WebAssemblyStackifier TableGen backend
Summary:
Replace its functionality with a TableGen InstrInfo relational
instruction mapping. Although arguably more complex than the TableGen
backend, the relational mapping is a smaller maintenance burden than a
TableGen backend.

Reviewers: aardappel, aheejin, dschuff

Subscribers: mgorny, sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53307

llvm-svn: 344962
2018-10-22 21:55:26 +00:00
Thomas Lively f04bed8e79 [WebAssembly][NFC] Remove repetition of Defs = [ARGUMENTS] (fixed)
llvm-svn: 344287
2018-10-11 20:21:22 +00:00
Thomas Lively ab37189f7e [WebAssembly] Revert rL344180, which was breaking expensive checks
llvm-svn: 344280
2018-10-11 18:45:48 +00:00
Thomas Lively eff0542c56 [WebAssembly][NFC] Remove repetition of Defs = [ARGUMENTS]
Summary:
By moving that line into the `I` multiclass.

Reviewers: aheejin

Subscribers: dschuff, sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53093

llvm-svn: 344180
2018-10-10 20:40:54 +00:00
Wouter van Oortmerssen e0403f13c4 [WebAssembly] Simplified selecting asmmatcher stack instructions.
Summary:
By using the existing isCodeGenOnly bit in the tablegen defs, as
suggested by tlively in https://reviews.llvm.org/D51662

Tested: llvm-lit -v `find test -name WebAssembly`

Reviewers: tlively

Subscribers: dschuff, sbc100, jgravelle-google, aheejin, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D52373

llvm-svn: 342772
2018-09-21 20:53:55 +00:00
Wouter van Oortmerssen 8a9cb242fb [WebAssembly] Added default stack-only instruction mode for MC.
Summary:
Made it convert from register to stack based instructions, and removed the registers.
Fixes to related code that was expecting register based instructions.
Added the correct testing flag to all tests, depending on what the
format they were expecting so far.
Translated one test to stack format as example: reg-stackify-stack.ll

tested:
llvm-lit -v `find test -name WebAssembly`
unittests/MC/*

Reviewers: dschuff, sunfish

Subscribers: sbc100, jgravelle-google, eraman, aheejin, llvm-commits, jfb

Differential Revision: https://reviews.llvm.org/D51241

llvm-svn: 340750
2018-08-27 15:45:51 +00:00
Heejin Ahn ff363539c6 [WebAssembly] Add hasSideEffects flag to catch instructions
Summary:
`catch` instruction certainly has rather huge side effects and the flag
was missing. At the moment this does not change any unit tests we
currently have.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D50919

llvm-svn: 340433
2018-08-22 18:22:45 +00:00
Heejin Ahn ed5e06b0a7 [WebAssembly] Add isEHScopeReturn instruction property
Summary:
So far, `isReturn` property is used to mean both a return instruction
from a functon and the end of an EH scope, a scope that starts with a EH
scope entry BB and ends with a catchret or a cleanupret instruction.
Because WinEH uses funclets, all EH-scope-ending instructions are also
real return instruction from a function. But for wasm, they only serve
as the end marker of an EH scope but not a return instruction that
exits a function. This mismatch caused incorrect prolog and epilog
generation in wasm EH scopes. This patch fixes this.

This patch is in the same vein with rL333045, which splits
`MachineBasicBlock::isEHFuncletEntry` into `isEHFuncletEntry` and
`isEHScopeEntry`.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D50653

llvm-svn: 340325
2018-08-21 19:44:11 +00:00
Heejin Ahn c9c711a0ac [WebAssembly] Fix encoding of non-SIMD vector-typed instructions
Previously SIMD_I was the same as a normal instruction except for the
addition of a HasSIM128 predicate. However, rL339186 changed the
encoding of SIMD_I instructions to automatically contain the SIMD
prefix byte. This broke the encoding of non-SIMD vector-typed
instructions, which had instantiated SIMD_I. This CL corrects this
error.

Reviewers: aheejin

Subscribers: sunfish, jgravelle-google, sbc100, llvm-commits

Differential Revision: https://reviews.llvm.org/D50682

Patch by Thomas Lively (tlively)

llvm-svn: 339710
2018-08-14 19:03:36 +00:00
Wouter van Oortmerssen a7be375586 Revert "[WebAssembly] Added default stack-only instruction mode for MC."
This reverts commit 917a99b71ce21c975be7bfbf66f4040f965d9f3c.

llvm-svn: 339630
2018-08-13 23:12:49 +00:00
Wouter van Oortmerssen ab26bd0647 [WebAssembly] Added default stack-only instruction mode for MC.
Summary:
Moved Explicit Locals pass to last.
Made that pass obligatory.
Made it convert from register to stack based instructions, and removed the registers.
Fixes to related code that was expecting register based instructions.
Added the correct testing flag to all tests, depending on what the
format they were expecting so far.
Translated one test to stack format as example: reg-stackify-stack.ll

tested:
llvm-lit -v `find test -name WebAssembly`
unittests/MC/*

Reviewers: dschuff, sunfish

Subscribers: jfb, llvm-commits, aheejin, eraman, jgravelle-google, sbc100

Differential Revision: https://reviews.llvm.org/D50568

llvm-svn: 339474
2018-08-10 21:32:47 +00:00
Derek Schuff 51ed131ed2 [WebAssembly] Update SIMD binary arithmetic
Add missing SIMD types (v2f64) and binary ops. Also adds
tablegen support for automatically prepending prefix byte to SIMD
opcodes.

Differential Revision: https://reviews.llvm.org/D50292

Patch by Thomas Lively

llvm-svn: 339186
2018-08-07 21:24:01 +00:00
Heejin Ahn 47068a42d2 [WebAssembly] Add missing -mattr=+exception-handling guards
Summary:
The use of exception handling instructions should only be enabled with
`-mattr=+exception-handling` option.

Reviewers: jgravelle-google

Subscribers: dschuff, sbc100, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D49391

llvm-svn: 337425
2018-07-18 21:42:22 +00:00
Heejin Ahn 6279d71227 [WebAssembly] Make rethrow instruction take a target BB argument
Summary:
This patch changes the rethrow instruction to take a BB argument in LLVM
backend, like `br` and `br_if`s. This BB is a target catch BB the
rethrow instruction unwinds to. This BB argument will be converted to an
relative depth immediate at the end of CFGStackify pass, as in the same
way of branches.

RETHROW_TO_CALLER is a codegen-only instruction that should be used when
a rethrow instruction does not have an unwind destination BB, i.e., it
should rethrow to its caller function.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D48260

llvm-svn: 334998
2018-06-18 23:54:29 +00:00
Wouter van Oortmerssen 48dac3109e [WebAssembly] Modified tablegen defs to have 2 parallel instuction sets.
Summary:
One for register based, much like the existing definitions,
and one for stack based (suffix _S).

This allows us to use registers in most of LLVM (which works better),
and stack based in MC (which results in a simpler and more readable
assembler / disassembler).

Tried to keep this change as small as possible while passing tests,
follow-up commit will:
- Add reg->stack conversion in MI.
- Fix asm/disasm in MC to be stack based.
- Fix emitter to be stack based.

tests passing:
llvm-lit -v `find test -name WebAssembly`

test/CodeGen/WebAssembly
test/MC/WebAssembly
test/MC/Disassembler/WebAssembly
test/DebugInfo/WebAssembly
test/CodeGen/MIR/WebAssembly
test/tools/llvm-objdump/WebAssembly

Reviewers: dschuff, sbc100, jgravelle-google, sunfish

Subscribers: aheejin, JDevlieghere, llvm-commits

Differential Revision: https://reviews.llvm.org/D48183

llvm-svn: 334985
2018-06-18 21:22:44 +00:00
Heejin Ahn 9786946731 [WebAssembly] Simple comment fix. NFC.
llvm-svn: 334899
2018-06-17 00:37:56 +00:00
Sam Clegg 537afe6f0e [WebAssembly] Fix .td files after rL333900
Differential Revision: https://reviews.llvm.org/D47727

llvm-svn: 333928
2018-06-04 16:59:26 +00:00
Heejin Ahn 5ef4d5f9c1 [WebAssembly] Support instruction selection for catching exceptions
Summary:
This lowers exception catching-related instructions:
1. Lowers `wasm.catch` intrinsic to `catch` instruction
2. Removes `catchpad` and `cleanuppad` instructions; they are not
necessary after isel phase. (`MachineBasicBlock::isEHFuncletEntry()` or
`MachineBasicBlock::isEHPad()` can be used instead.)
3. Lowers `catchret` and `cleanupret` instructions to pseudo `catchret`
and `cleanupret` instructions in isel, which will be replaced with other
instructions in `WebAssemblyExceptionPrepare` pass.
4. Adds 'WebAssemblyExceptionPrepare` pass, which is for running various
transformation for EH. Currently this pass only replaces `catchret` and
`cleanupret` instructions into appropriate wasm instructions to make
this patch successfully run until the end.

Currently this does not handle lowering of intrinsics related to LSDA
info generation (`wasm.landingpad.index` and `wasm.lsda`), because they
cannot be tested without implementing `EHStreamer`'s wasm-specific
handlers. They are marked as TODO, which is needed to make isel pass.
Also this does not generate `try` and `end_try` markers yet, which will
be handled in later patches.

This patch is based on the first wasm EH proposal.
(https://github.com/WebAssembly/exception-handling/blob/master/proposals/Exceptions.md)

Reviewers: dschuff, majnemer

Subscribers: jfb, sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D44090

llvm-svn: 333705
2018-05-31 22:25:54 +00:00
Sam Clegg 16c16827bc [WebAssembly] Initial Disassembler.
This implements a new table-gen emitter to create tables for
a wasm disassembler, and a dissassembler to use them.

Comes with 2 tests, that tests a few instructions manually. Is also able to
disassemble large .wasm files with objdump reasonably.

Not working so well, to be addressed in followups:
- objdump appears to be passing an incorrect starting point.
- since the disassembler works an instruction at a time, and it is
  disassembling stack instruction, it has no idea of pseudo register assignments.
  These registers are required for the instruction printing code that follows.
  For now, all such registers appear in the output as $0.

Patch by Wouter van Oortmerssen

Differential Revision: https://reviews.llvm.org/D45848

llvm-svn: 332052
2018-05-10 22:16:44 +00:00
Adrian Prantl 5f8f34e459 Remove \brief commands from doxygen comments.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.

Patch produced by

  for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done

Differential Revision: https://reviews.llvm.org/D46290

llvm-svn: 331272
2018-05-01 15:54:18 +00:00
Heejin Ahn 0de587296e [WebAssembly] Add except_ref as a first-class type
Summary: Add except_ref as a first-class type, according to the [[https://github.com/WebAssembly/exception-handling/blob/master/proposals/Level-1.md | Level 1 exception handling proposal ]].

Reviewers: dschuff

Subscribers: jfb, sbc100, llvm-commits

Differential Revision: https://reviews.llvm.org/D43706

llvm-svn: 326985
2018-03-08 04:05:37 +00:00
Heejin Ahn e4a8deea84 [WebAssembly] Gather EH instructions in one place. NFC.
Summary:
- Gather EH instructions in one place for easy tracking (more will be
  added later)
- Variable name change

Reviewers: dschuff

Subscribers: jfb, sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D43742

llvm-svn: 326522
2018-03-02 01:03:40 +00:00
Heejin Ahn ac62b05d05 [WebAssembly] Add support for exception handling instructions
Summary:
This adds backend support for throw, rethrow, try, and try_end instructions.
This needs the corresponding clang builtin support:
https://reviews.llvm.org/D34783
This follows the Wasm exception handling proposal in
https://github.com/WebAssembly/exception-handling/blob/master/proposals/Exceptions.md

Reviewers: sunfish, dschuff

Reviewed By: dschuff

Subscribers: jfb, sbc100, jgravelle-google

Differential Revision: https://reviews.llvm.org/D34826

llvm-svn: 306774
2017-06-30 00:43:15 +00:00
Dan Gohman d934cb8806 [WebAssembly] Basic support for Wasm object file encoding.
With the "wasm32-unknown-unknown-wasm" triple, this allows writing out
simple wasm object files, and is another step in a larger series toward
migrating from ELF to general wasm object support. Note that this code
and the binary format itself is still experimental.

llvm-svn: 296190
2017-02-24 23:18:00 +00:00