Commit Graph

747 Commits

Author SHA1 Message Date
Thomas Lively 1cb0b56607 [WebAssembly] Prototype i64x2.widen_{low,high}_i32x4_{s,u}
As proposed in https://github.com/WebAssembly/simd/pull/290. As usual, these
instructions are available only via builtin functions and intrinsics while they
are in the prototyping stage.

Differential Revision: https://reviews.llvm.org/D90504
2020-10-30 15:44:04 -07:00
Thomas Lively 6214be3a4a [WebAssembly] Remove unused FileCheck test prefixes
This commit removes unused FileCheck prefixes from WebAssembly test files to
avoid causing test failures once FileCheck disallows unused prefixes by default.
See D90281 and the corresponding llvm-dev thread for context.

Reviewed By: aardappel

Differential Revision: https://reviews.llvm.org/D90416
2020-10-29 13:37:55 -07:00
Thomas Lively be6f50798e [WebAssembly] Implement SIMD signselect instructions
As proposed in https://github.com/WebAssembly/simd/pull/124, using the opcodes
adopted by V8 in
https://chromium-review.googlesource.com/c/v8/v8/+/2486235/2/src/wasm/wasm-opcodes.h.
Uses new builtin functions and a new target intrinsic exclusively to ensure that
the new instructions are only emitted when a user explicitly opts in to using
them since they are still in the prototyping and evaluation phase.

Differential Revision: https://reviews.llvm.org/D90357
2020-10-29 11:06:20 -07:00
Thomas Lively 31e944556f [WebAssembly] Prototype extending multiplication SIMD instructions
As proposed in https://github.com/WebAssembly/simd/pull/376. This commit
implements new builtin functions and intrinsics for these instructions, but does
not yet add them to wasm_simd128.h because they have not yet been merged to the
proposal. These are the first instructions with opcodes greater than 0xff, so
this commit updates the MC layer and disassembler to handle that correctly.

Differential Revision: https://reviews.llvm.org/D90253
2020-10-28 09:38:59 -07:00
Thomas Lively 1992e30c2d [WebAssembly] Prototype i8x16.popcnt
As proposed at https://github.com/WebAssembly/simd/pull/379. Use a target
builtin and intrinsic rather than normal codegen patterns to make the
instruction opt-in until it is merged to the proposal and stabilized in engines.

Differential Revision: https://reviews.llvm.org/D89446
2020-10-15 21:18:22 +00:00
Thomas Lively 3f738d1f5e Reland "[WebAssembly] v128.load{8,16,32,64}_lane instructions"
This reverts commit 7c8385a352 with a typing fix
to an instruction selection pattern.
2020-10-15 19:32:34 +00:00
Thomas Lively 7c8385a352 Revert "[WebAssembly] v128.load{8,16,32,64}_lane instructions"
This reverts commit 7c6bfd90ab.
2020-10-15 15:49:36 +00:00
Thomas Lively 7c6bfd90ab [WebAssembly] v128.load{8,16,32,64}_lane instructions
Prototype the newly proposed load_lane instructions, as specified in
https://github.com/WebAssembly/simd/pull/350. Since these instructions are not
available to origin trial users on Chrome stable, make them opt-in by only
selecting them from intrinsics rather than normal ISel patterns. Since we only
need rough prototypes to measure performance right now, this commit does not
implement all the load and store patterns that would be necessary to make full
use of the offset immediate. However, the full suite of offset tests is included
to make it easy to track improvements in the future.

Since these are the first instructions to have a memarg immediate as well as an
additional immediate, the disassembler needed some additional hacks to be able
to parse them correctly. Making that code more principled is left as future
work.

Differential Revision: https://reviews.llvm.org/D89366
2020-10-15 15:33:10 +00:00
Thomas Lively 72c628e835 Reland "[WebAssembly] Emulate v128.const efficiently""
This reverts commit 432e4e56d3, which reverted 542523a61a. Two issues from
the original commit have been fixed. First, MSVC does not like when std::array
is initialized with only single braces, so this commit switches to using the
more portable double braces. Second, there was a subtle endianness bug that
prevented the original commit from working correctly on big-endian machines,
which has been fixed by switching to using endianness-agnostic bit twiddling
instead of type punning.

Differential Revision: https://reviews.llvm.org/D88773
2020-10-13 04:36:59 +00:00
Thomas Lively d8f58bf53a [WebAssembly] Prototype i16x8.q15mulr_sat_s
This saturating, rounding, Q-format multiplication instruction is proposed in
https://github.com/WebAssembly/simd/pull/365.

Differential Revision: https://reviews.llvm.org/D88968
2020-10-09 21:17:53 +00:00
Heejin Ahn 750b3ddd80 [WebAssembly] Handle indirect uses of longjmp
In LowerEmscriptenEHSjLj, `longjmp` used to be replaced with
`emscripten_longjmp_jmpbuf(jmp_buf*, i32)`, which will eventually be
lowered to `emscripten_longjmp(i32, i32)`. The reason we used two
different names was because they had different signatures in the IR
pass.

D88697 fixed this by only using `emscripten_longjmp(i32, i32)` and
adding a `ptrtoint` cast to its first argument, so
```
longjmp(buf, 0)
```
becomes
```
emscripten_longjmp((i32)buf, 0)
```

But this assumed all uses of `longjmp` was a direct call to it, which
was not the case. This patch handles indirect uses of `longjmp` by
replacing
```
longjmp
```
with
```
(i32(*)(jmp_buf*, i32))emscripten_longjmp
```

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D89032
2020-10-08 11:37:19 -07:00
Heejin Ahn 3bba91f64e [WebAssembly] Rename Emscripten EH functions
Renaming for some Emscripten EH functions has so far been done in
wasm-emscripten-finalize tool in Binaryen. But recently we decided to
make a compilation/linking path that does not rely on
wasm-emscripten-finalize for modifications, so here we move that
functionality to LLVM.

Invoke wrappers are generated in LowerEmscriptenEHSjLj pass, but final
wasm types are not available in the IR pass, we need to rename them at
the end of the pipeline.

This patch also removes uses of `emscripten_longjmp_jmpbuf` in
LowerEmscriptenEHSjLj pass, replacing that with `emscripten_longjmp`.
`emscripten_longjmp_jmpbuf` is lowered to `emscripten_longjmp`, but
previously we generated calls to `emscripten_longjmp_jmpbuf` in
LowerEmscriptenEHSjLj pass because it takes `jmp_buf*` instead of `i32`.
But we were able use `ptrtoint` to make it use `emscripten_longjmp`
directly here.

Addresses:
https://github.com/WebAssembly/binaryen/issues/3043
https://github.com/WebAssembly/binaryen/issues/3081

Companions:
https://github.com/WebAssembly/binaryen/pull/3191
https://github.com/emscripten-core/emscripten/pull/12399

Reviewed By: dschuff, tlively, sbc100

Differential Revision: https://reviews.llvm.org/D88697
2020-10-07 09:42:49 -07:00
Stella Stamenova 432e4e56d3 Revert "[WebAssembly] Emulate v128.const efficiently"
This reverts commit 542523a61a.
2020-10-02 09:26:21 -07:00
Thomas Lively 542523a61a [WebAssembly] Emulate v128.const efficiently
v128.const was recently implemented in V8, but until it rolls into Chrome
stable, we can't enable it in the WebAssembly backend without breaking origin
trial users. So far we have been lowering build_vectors that would otherwise
have been lowered to v128.const to splats followed by sequences of replace_lane
instructions to initialize each lane individually. That produces large and
inefficient code, so this patch introduces new logic to lower integer vector
constants to a single i64x2.splat where possible, with at most a single
i64x2.replace_lane following it if necessary.

Adapted from a patch authored by @omnisip.

Differential Revision: https://reviews.llvm.org/D88591
2020-10-02 00:28:06 -07:00
Thomas Lively 89fe083c19 [WebAssembly] Check features before making SjLj vars thread-local
1c5a3c4d38 updated the variables inserted by Emscripten SjLj lowering to be
thread-local, depending on the CoalesceFeaturesAndStripAtomics pass to downgrade
them to normal globals if the target features did not support TLS. However, this
had the unintended side effect of preventing all non-TLS-supporting objects from
being linked into modules with shared memory, because stripping TLS marks an
object as thread-unsafe. This patch fixes the problem by only making the SjLj
lowering variables thread-local if the target machine supports TLS so that it
never introduces new usage of TLS that will be stripped. Since SjLj lowering
works on Modules instead of Functions, this required that the
WebAssemblyTargetMachine have its feature string updated to reflect the
coalesced features collected from all the functions so that a
WebAssemblySubtarget can be created without using any particular function.

Differential Revision: https://reviews.llvm.org/D88323
2020-09-25 11:45:16 -07:00
Thomas Lively 1c5a3c4d38 [WebAssembly] Make SjLj lowering globals thread-local
Emscripten's longjump and exception mechanism depends on two global variables,
`__THREW__` and `__threwValue`, which are changed to be defined as thread-local
in https://github.com/emscripten-core/emscripten/pull/12056. This patch updates
the corresponding code in the WebAssembly backend to properly declare these
globals as thread-local as well.

Differential Revision: https://reviews.llvm.org/D88262
2020-09-24 14:56:19 -07:00
Heejin Ahn d25c17f317 [WebAssembly] Fix fixEndsAtEndOfFunction for try-catch
When the function return type is non-void and `end` instructions are at
the very end of a function, CFGStackify's `fixEndsAtEndOfFunction`
function fixes the corresponding block/loop/try's type to match the
function's return type. This is applied to consecutive `end` markers at
the end of a function. For example, when the function return type is
`i32`,
```
block i32    ;; return type is fixed to i32
  ...
  loop i32   ;; return type is fixed to i32
    ...
  end_loop
end_block
end_function
```

But try-catch is a little different, because it consists of two parts:
a try part and a catch part, and both parts' return type should satisfy
the function's return type. Which means,
```
try i32      ;; return type is fixed to i32
  ...
  block i32  ;; this should be changed i32 too!
    ...
  end_block
catch
  ...
end_try
end_function
```
As you can see in this example, it is not sufficient to only `end`
instructions at the end of a function; in case of `try`, we should
check instructions before `catch`es, in case their corresponding `try`'s
type has been fixed.

This changes `fixEndsAtEndOfFunction`'s algorithm to use a worklist
that contains a reverse iterator, each of which is a starting point for
a new backward `end` instruction search.

Fixes https://bugs.llvm.org/show_bug.cgi?id=47413.

Reviewed By: dschuff, tlively

Differential Revision: https://reviews.llvm.org/D87207
2020-09-08 09:27:40 -07:00
Thomas Lively caee15a0ed [WebAssembly] Fix incorrect assumption of simple value types
Fixes PR47375, in which an assertion was triggering because
WebAssemblyTargetLowering::isVectorLoadExtDesirable was improperly
assuming the use of simple value types.

Differential Revision: https://reviews.llvm.org/D87110
2020-09-06 15:42:21 -07:00
Jay Foad b7e3599a22 [SelectionDAG] Handle non-power-of-2 bitwidths in expandROT
Differential Revision: https://reviews.llvm.org/D86449
2020-08-26 09:20:46 +01:00
Thomas Lively cc612c2908 [WebAssembly] Fix FastISel address calculation bug
Fixes PR47040, in which an assertion was improperly triggered during
FastISel's address computation. The issue was that an `Address` set to
be relative to the FrameIndex with offset zero was incorrectly
considered to have an unset base. When the left hand side of an add
set the Address to be 0 off the FrameIndex, the right side would not
detect that the Address base had already been set and could try to set
the Address to be relative to a register instead, triggering an
assertion.

This patch fixes the issue by explicitly tracking whether an `Address`
has been set rather than interpreting an offset of zero to mean the
`Address` has not been set.

Differential Revision: https://reviews.llvm.org/D85581
2020-08-08 15:23:11 -07:00
Thomas Lively cb32792210 [WebAssembly] Implement prototype v128.load{32,64}_zero instructions
Specified in https://github.com/WebAssembly/simd/pull/237, these
instructions load the first vector lane from memory and zero the other
lanes. Since these instructions are not officially part of the SIMD
proposal, they are only available on an opt-in basis via LLVM
intrinsics and clang builtin functions. If these instructions are
merged to the proposal, this implementation will change so that the
instructions will be generated from normal IR. At that point the
intrinsics and builtin functions would be removed.

This PR also changes the opcodes for the experimental f32x4.qfm{a,s}
instructions because their opcodes conflicted with those of the
v128.load{32,64}_zero instructions. The new opcodes were chosen to
match those used in V8.

Differential Revision: https://reviews.llvm.org/D84820
2020-08-03 13:54:00 -07:00
Wouter van Oortmerssen ce1eb7af9d [WebAssembly] Fixed 64-bit indices in br_table
LLVM selection dag assumes "switch" indices are pointer sized, which causes problems for our 32-bit br_table. The new function ensures 32-bit operands don't get unnecessarily extended, and 64-bit operands get truncated.

Note that the changes to the existing test test exactly that: the addition of -NEXT in 2 places ensures no extension is inserted (which the test previously ignored) and that the wrap is present (previously omitted in wasm64 mode).

Differential Revision: https://reviews.llvm.org/D84705
2020-07-30 10:52:16 -07:00
Heejin Ahn 276f9e8cfa [WebAssembly] Fix getBottom for loops
When it was first created, CFGSort only made sure BBs in each
`MachineLoop` are sorted together. After we added exception support,
CFGSort now also sorts BBs in each `WebAssemblyException`, which
represents a `catch` block, together, and
`Region` class was introduced to be a thin wrapper for both
`MachineLoop` and `WebAssemblyException`.

But how we compute those loops and exceptions is different.
`MachineLoopInfo` is constructed using the standard loop computation
algorithm in LLVM; the definition of loop is "a set of BBs that are
dominated by a loop header and have a path back to the loop header". So
even if some BBs are semantically contained by a loop in the original
program, or in other words dominated by a loop header, if they don't
have a path back to the loop header, they are not considered a part of
the loop. For example, if a BB is dominated by a loop header but
contains `call abort()` or `rethrow`, it wouldn't have a path back to
the header, so it is not included in the loop.

But `WebAssemblyException` is wasm-specific data structure, and its
algorithm is simple: a `WebAssemblyException` consists of an EH pad and
all BBs dominated by the EH pad. So this scenario is possible: (This is
also the situation in the newly added test in cfg-stackify-eh.ll)

```
Loop L: header, A, ehpad, latch
Exception E: ehpad, latch, B
```
(B contains `abort()`, so it does not have a path back to the loop
header, so it is not included in L.)

And it is sorted in this order:
```
header
A
ehpad
latch
B
```

And when CFGStackify places `end_loop` or `end_try` markers, it
previously used `WebAssembly::getBottom()`, which returns the latest BB
in the sorted order, and placed the marker there. So in this case the
marker placements will be like this:
```
loop
  header
  try
    A
  catch
    ehpad
    latch
end_loop         <-- misplaced!
    B
  end_try
```
in which nesting between the loop and the exception is not correct.
`end_loop` marker has to be placed after `B`, and also after `end_try`.

Maybe the fundamental way to solve this problem is to come up with our
own algorithm for computing loop region too, in which we include all BBs
dominated by a loop header in a loop. But this takes a lot more effort.
The only thing we need to fix is actually, `getBottom()`. If we make it
return the right BB, which means in case of a loop, the latest BB of the
loop itself and all exceptions contained in there, we are good.

This renames `Region` and `RegionInfo` to `SortRegion` and
`SortRegionInfo` and extracts them into their own file. And add
`getBottom` to `SortRegionInfo` class, from which it can access
`WebAssemblyExceptionInfo`, so that it can compute a correct bottom
block for loops.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D84724
2020-07-29 10:36:32 -07:00
Thomas Lively 11bb7eef41 [WebAssembly] Remove intrinsics for SIMD widening ops
Instead, pattern match extends of extract_subvectors to generate
widening operations. Since extract_subvector is not a legal node, this
is implemented via a custom combine that recognizes extract_subvector
nodes before they are legalized. The combine produces custom ISD nodes
that are later pattern matched directly, just like the intrinsic was.

Also removes the clang builtins for these operations since the
instructions can now be generated from portable code sequences.

Differential Revision: https://reviews.llvm.org/D84556
2020-07-28 18:25:55 -07:00
Thomas Lively ffd8c23ccb [WebAssembly] Implement truncating vector stores
Rather than expanding truncating stores so that vectors are stored one
lane at a time, lower them to a sequence of instructions using
narrowing operations instead, when possible. Since the narrowing
operations have saturating semantics, but truncating stores require
truncation, mask the stored value to manually truncate it before
narrowing. Also, since narrowing is a binary operation, pass in the
original vector as the unused second argument.

Differential Revision: https://reviews.llvm.org/D84377
2020-07-28 17:46:45 -07:00
Thomas Lively a459459248 [WebAssembly] Fix store_unfolded_offset tests in simd-offset.ll
These tests were previously duplicates of the
unfolded_gep_negative_offset tests, and this change updates them to
test what they were meant to test.

Differential Revision: https://reviews.llvm.org/D84365
2020-07-23 16:05:20 -07:00
Thomas Lively 51cd326f99 [WebAssembly] Autogenerate checks in simd-offset.ll
Implementing new functionality tested in this file requires adding new
tests for many IR addressing patterns, which can be a large
maintenance burden. This patch makes adding tests easier by switching
to using autogenerated checks. This patch also removes the testing
mode that has simd128 disabled because it would produce very large
checks and is not particularly interesting.

Differential Revision: https://reviews.llvm.org/D84288
2020-07-22 10:12:26 -07:00
Wouter van Oortmerssen cc1b9b680f [WebAssembly] 64-bit (function) pointer fixes.
Accounting for the fact that Wasm function indices are 32-bit, but in wasm64 we want uniform 64-bit pointers.
Includes reloc types for 64-bit table indices.

Differential Revision: https://reviews.llvm.org/D83729
2020-07-16 14:10:22 -07:00
Thomas Lively ecb2e5bcd7 [WebAssembly] Implement v128.select
Although the SIMD spec proposal does not specifically include a
select instruction, the select instruction in MVP WebAssembly is
polymorphic over the selected types, so it is able to work on v128
values when they are enabled. This patch introduces a new variant of
the select instruction for each legal vector type. Additional ISel
patterns are adapted from the SELECT_I32 and SELECT_I64 patterns.

Depends on D83736.

Differential Revision: https://reviews.llvm.org/D83737
2020-07-16 11:37:25 -07:00
Thomas Lively f7868f87ac [WebAssembly] Autogenerate tests for simd-select.ll
Updating the simd-select.ll tests manually with consistent named
regexps for the register numbers was taking more time than it was
worth, so this patch updates that test file to have autogenerated
output. This is not a significant readability regression because the
tests in that file are all very small.

Depends on D83734.

Differential Revision: https://reviews.llvm.org/D83736
2020-07-16 11:19:09 -07:00
Thomas Lively f0f9787646 [WebAssembly] Lower vselect to v128.bitselect
We were previously expanding vselect and matching on the expansion to
generate bitselects, but in some cases the expansion would be further
combined and a bitselect would not get generated. This patch improves
codegen in those cases by legalizing vselect and lowering it to
v128.bitselect. The old pattern that matches the expansion is still
useful for lowering IR that already uses the expansion rather than a
select operation.

Differential Revision: https://reviews.llvm.org/D83734
2020-07-16 11:11:19 -07:00
Roger Ferrer Ibanez 14bc5e149d [DAGCombiner] Rebuild (setcc x, y, ==) from (xor (xor x, y), 1)
The existing code already considered this case. Unfortunately a typo in
the condition prevents it from triggering. Also the existing code, had
it run, forgot to do the folding.

This fixes PR42876.

Differential Revision: https://reviews.llvm.org/D65802
2020-07-15 07:34:22 +00:00
Thomas Lively b59c6fcaf3 [WebAssembly] Prefer v128.const for constant splats
In BUILD_VECTOR lowering, we used to generally prefer using splats
over v128.const instructions because v128.const has a very large
encoding. However, in d5b7a4e2e8 we switched to preferring consts
because they are expected to be more efficient in engines. This patch
updates the ISel patterns to match this current preference.

Differential Revision: https://reviews.llvm.org/D83581
2020-07-10 18:27:52 -07:00
Thomas Lively 043eaa9a4a [WebAssembly][NFC] Simplify vector shift lowering and add tests
This patch builds on 0d7286a652 by simplifying the code for detecting
splat values and adding new tests demonstrating the lowering of
splatted absolute value shift amounts, which are common in code
generated by Halide. The lowering is very bad right now, but
subsequent patches will improve it considerably. The tests will be
useful for evaluating the improvements in those patches.

Reviewed By: aheejin

Differential Revision: https://reviews.llvm.org/D83493
2020-07-10 00:18:59 -07:00
Heejin Ahn 7e6793aa33 [WebAssembly] Generate unreachable after __stack_chk_fail
`__stack_chk_fail` does not return, but `unreachable` was not generated
following `call __stack_chk_fail`. This had a possibility to generate an
invalid binary for functions with a return type, because
`__stack_chk_fail`'s return type is void and `call __stack_chk_fail` can
be the last instruction in the function whose return type is non-void.
Generating `unreachable` after it makes sure CFGStackify's
`fixEndsAtEndOfFunction` handles it correctly.

Reviewed By: tlively

Differential Revision: https://reviews.llvm.org/D83277
2020-07-08 01:02:05 -07:00
Thomas Lively 0d7286a652 [WebAssembly] Avoid scalarizing vector shifts in more cases
Since WebAssembly's vector shift instructions take a scalar shift
amount rather than a vector shift amount, we have to check in ISel
that the vector shift amount is a splat. Previously, we were checking
explicitly for splat BUILD_VECTOR nodes, but this change uses the
standard utilities for detecting splat values that can handle more
complex splat patterns. Since the C++ ISel lowering is now more
general than the ISel patterns, this change also simplifies shift
lowering by using the C++ lowering for all SIMD shifts rather than
mixing C++ and normal pattern-based lowering.

This change improves ISel for shifts to the point that the
simd-shift-unroll.ll regression test no longer tests the code path it
was originally meant to test. The bug corresponding to that regression
test is no longer reproducible with its original reported reproducer,
so rather than try to fix the regression test, this change just
removes it.

Differential Revision: https://reviews.llvm.org/D83278
2020-07-07 10:45:26 -07:00
Wouter van Oortmerssen 16d83c395a [WebAssembly] Added 64-bit memory.grow/size/copy/fill
This covers both the existing memory functions as well as the new bulk memory proposal.
Added new test files since changes where also required in the inputs.

Also removes unused init/drop intrinsics rather than trying to make them work for 64-bit.

Differential Revision: https://reviews.llvm.org/D82821
2020-07-06 12:49:50 -07:00
Thomas Lively 8df30d988e [WebAssembly] Do not omit range checks for i64 switches
Summary:
Since the br_table instruction takes an i32, switches over i64s (and
larger integers) must use the i32.wrap_i64 instruction to truncate the
table index. This truncation makes numbers just over 2^32
indistinguishable from small numbers, so it was a miscompilation to
omit the range check preceding these br_tables. This change fixes the
problem by skipping the "fixing" of the br_table when the range check
is an i64 instruction.

Fixes PR46447.

Reviewers: aheejin, dschuff, kripken

Reviewed By: kripken

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D83017
2020-07-03 17:15:39 -07:00
Qiu Chaofan aa4fd7d848 [NFC] Fix typo in triples from unkown to unknown 2020-07-02 16:21:54 +08:00
Wouter van Oortmerssen b9a539c010 [WebAssembly] Adding 64-bit versions of __stack_pointer and other globals
We have 6 globals, all of which except for __table_base are 64-bit under wasm64.

Differential Revision: https://reviews.llvm.org/D82130
2020-06-25 15:52:44 -07:00
Eric Christopher cf23852587 [Target] As part of using inclusive language within the llvm project,
migrate away from the use of blacklist and whitelist.

This change affects an internal llvm command line option.
2020-06-20 00:06:39 -07:00
Heejin Ahn 83c26eae23 [WebAssembly] Remove TEEs when dests are unstackified
When created in RegStackify pass, `TEE` has two destinations, where
op0 is stackified and op1 is not. But it is possible that
op0 becomes unstackified in `fixUnwindMismatches` function in
CFGStackify pass when a nested try-catch-end is introduced, violating
the invariant of `TEE`s destinations.

In this case we convert the `TEE` into two `COPY`s, which will
eventually be resolved in ExplicitLocals.

Reviewed By: dschuff

Differential Revision: https://reviews.llvm.org/D81851
2020-06-19 14:55:21 -07:00
Sam Clegg 7ee758d691 [WebAssembly] MC: Fix for data aliases with offsets (getelementptr)
For some reason we hadn't seen such cases in the wild which makes
me think that clang and rustc don't generate these.  In the bug which
reproduces it only occurs with LTO so my guess is that some LTO pass
is creating this alias + gep.

See: https://github.com/emscripten-core/emscripten/issues/8731

Differential Revision: https://reviews.llvm.org/D79462
2020-06-17 16:25:50 -07:00
Thomas Lively 49754dcf22 [WebAssembly] Fix bug in FixBrTables and use branch analysis utils
Summary:
This commit fixes a bug in the FixBrTables pass in which an
unconditional branch from the switch header block to the jump table
block was not removed before the blocks were combined. The result was
an invalid CFG in the MachineFunction. This commit also switches from
using bespoke branch analysis and deletion code to using the standard
utilities for the same.

Reviewers: aheejin, dschuff

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D81909
2020-06-17 12:34:45 -07:00
Wouter van Oortmerssen d9e0bbd17b [WebAssembly] Adding 64-bit versions of all load & store ops.
Context: https://github.com/WebAssembly/memory64/blob/master/proposals/memory64/Overview.md
This is just a first step, adding the new instruction variants while keeping the existing 32-bit functionality working.
Some of the basic load/store tests have new wasm64 versions that show that the basics of the target are working.
Further features need implementation, but these will be added in followups to keep things reviewable.

Differential Revision: https://reviews.llvm.org/D80769
2020-06-15 08:31:56 -07:00
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 a96414527c [NFC][WebAssembly] Add tests for alignment on new SIMD loads
Summary:
The natural alignments for extending and splatting loads had not
previously been tested. It is good to have them tested because they
are non-obvious details in the SIMD spec proposal.

Reviewers: aheejin

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D81303
2020-06-09 13:46:12 -07:00
Thomas Lively b7d369280b [WebAssembly] Implement prototype SIMD rounding instructions
Summary:
As specified in https://github.com/WebAssembly/simd/pull/232. These
instructions are implemented as LLVM intrinsics for now rather than
normal ISel patterns to make these instructions opt-in. Once the
instructions are merged to the spec proposal, the intrinsics will be
replaced with proper ISel patterns.

Reviewers: aheejin

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

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D81222
2020-06-09 10:14:14 -07:00
James Y Knight 748d92b4d3 Simplify MachineVerifier's block-successor verification.
There's two properties we want to verify:

1. That the successors returned by analyzeBranch are in the CFG
   successor list, and
2. That there are no extraneous successors are in the CFG successor
   list.

The previous implementation mostly accomplished this, but in a very
convoluted manner.

Differential Revision: https://reviews.llvm.org/D79793
2020-06-06 22:30:51 -04:00
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