Based off a discussion on D110100, we should be avoiding default CostKinds whenever possible.
This initial patch removes them from the 'inner' target implementation callbacks - these should only be used by the main TTI calls, so this should guarantee that we don't cause changes in CostKind by missing it in an inner call. This exposed a few missing arguments in getGEPCost and reduction cost calls that I've cleaned up.
Differential Revision: https://reviews.llvm.org/D110242
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.
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
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
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
On some architectures such as Arm and X86 the encoding for a nop may
change depending on the subtarget in operation at the time of
encoding. This change replaces the per module MCSubtargetInfo retained
by the targets AsmBackend in favour of passing through the local
MCSubtargetInfo in operation at the time.
On Arm using the architectural NOP instruction can have a performance
benefit on some implementations.
For Arm I've deleted the copy of the AsmBackend's MCSubtargetInfo to
limit the chances of this causing problems in the future. I've not
done this for other targets such as X86 as there is more frequent use
of the MCSubtargetInfo and it looks to be for stable properties that
we would not expect to vary per function.
This change required threading STI through MCNopsFragment and
MCBoundaryAlignFragment.
I've attempted to take into account the in tree experimental backends.
Differential Revision: https://reviews.llvm.org/D45962
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
This ISD node/wrapper represents am address which is relative to a base
address and therefore lowers to `i32.const` rather than `global.get`.
Use this wrapper type for TLS-relative addresses, paving the way for the
non-REL wrapper to be used to external TLS address once those are
supported.
Differential Revision: https://reviews.llvm.org/D109179
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
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
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
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
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
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
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
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
Emscripten SjLj and (soon-to-be-added) Wasm SjLj transformation share
many steps:
1. Initialize `setjmpTable` and `setjmpTableSize` in the entry BB
2. Handle `setjmp` callsites
3. Handle `longjmp` callsites
4. Cleanup and update SSA
1, 3, and 4 are identical for Emscripten SjLj and Wasm SjLj. Only the
step 2 is different. This CL extracts the current Emscripten SjLj's
longjmp callsites handling into a function. The reason to make this a
separate CL is, without this, the diff tool cannot compare things well
in the presence of moved code and added code in the followup Wasm SjLj
CL, and it ends up mixing them together, making the diff unreadable.
Also fixes some typos and variable names. So far we've been calling the
buffer argument to `setjmp` and `longjmp` `jmpbuf`, but the name used in
the man page for those functions is `env`, so updated them to be
consistent.
Reviewed By: tlively
Differential Revision: https://reviews.llvm.org/D108728
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
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
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
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
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
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
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
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
AttributeList::hasAttribute() is confusing, use clearer methods like
hasParamAttr()/hasRetAttr().
Add hasRetAttr() since it was missing from AttributeList.
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
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
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
`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
- 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
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
I'm not sure this is the best way to approach this,
but the situation is rather not very detectable unless we explicitly call it out when refusing to advise to unroll.
Reviewed By: efriedma
Differential Revision: https://reviews.llvm.org/D107271
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
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
Replace the clang builtins and LLVM intrinsics for the SIMD extmul instructions
with normal codegen patterns.
Differential Revision: https://reviews.llvm.org/D106724
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
Both `__THREW__` and `__threwValue` are global variables, and we have
been distinguishing the global variable `__THREW__` and the loaded value
`%__THREW__.val` in comments but not doing it for `__threwValue`. Made
the pseudocode comments consistent for both variables.
Reviewed By: dschuff
Differential Revision: https://reviews.llvm.org/D106524
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
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
Replace the experimental clang builtins and LLVM intrinsics for these
instructions with normal instruction selection patterns. The wasm_simd128.h
intrinsics header was already using portable code for the corresponding
intrinsics, so now it produces the correct instructions.
Differential Revision: https://reviews.llvm.org/D106400
Debug info sections need R_WASM_FUNCTION_OFFSET_I32 relocs (with FK_Data_4 fixup
kinds) to refer to functions (instead of R_WASM_TABLE_INDEX as is used in data
sections). Usually this is done in a convoluted way, with unnamed temp data
symbols which target the start of the function, in which case
WasmObjectWriter::recordRelocation converts it to use the section symbol
instead. However in some cases the function can actually be undefined; in this
case the dwarf generator uses the function symbol (a named undefined function
symbol) instead. In that case the section-symbol transform doesn't work and we
need to generate the correct reloc type a different way. In this change
WebAssemblyWasmObjectWriter::getRelocType takes the fixup section type into
account to choose the correct reloc type.
Fixes PR50408
Differential Revision: https://reviews.llvm.org/D103557
Replace the experimental clang builtins and LLVM intrinsics for these
instructions with normal codegen patterns. Resolves PR50435.
Differential Revision: https://reviews.llvm.org/D106019
Replace the experimental clang builtin and LLVM intrinsics for these
instructions with normal codegen patterns. Resolves PR50433.
Differential Revision: https://reviews.llvm.org/D105950
Replace the clang builtin function and LLVM intrinsic for
f32x4.demote_zero_f64x2 with combines from normal SDNodes. Also add missing
combines for i32x4.trunc_sat_zero_f64x2_{s,u}, which share the same pattern.
Differential Revision: https://reviews.llvm.org/D105755
Replace the clang builtin function and LLVM intrinsic previously used to select
the f64x2.promote_low_f32x4 instruction with custom combines from standard
SelectionDAG nodes. Implement the new combines to share code with the similar
combines for f64x2.convert_low_i32x4_{s,u}. Resolves PR50232.
Differential Revision: https://reviews.llvm.org/D105675
This to protect against non-sensical instruction sequences being assembled,
which would either cause asserts/crashes further down, or a Wasm module being output that doesn't validate.
Unlike a validator, this type checker is able to give type-errors as part of the parsing process, which makes the assembler much friendlier to be used by humans writing manual input.
Because the MC system is single pass (instructions aren't even stored in MC format, they are directly output) the type checker has to be single pass as well, which means that from now on .globaltype and .functype decls must come before their use. An extra pass is added to Codegen to collect information for this purpose, since AsmPrinter is normally single pass / streaming as well, and would otherwise generate this information on the fly.
A `-no-type-check` flag was added to llvm-mc (and any other tools that take asm input) that surpresses type errors, as a quick escape hatch for tests that were not intended to be type correct.
This is a first version of the type checker that ignores control flow, i.e. it checks that types are correct along the linear path, but not the branch path. This will still catch most errors. Branch checking could be added in the future.
Differential Revision: https://reviews.llvm.org/D104945
Override the `shouldScalarizeBinop` target lowering hook using the same
implementation used in the x86 backend. This causes `extract_vector_elt`s of
vector binary ops to be scalarized if the scalarized version would be supported.
Differential Revision: https://reviews.llvm.org/D105646
WebAssembly's shift instructions implicitly masks the shift count, so optimize
out redundant explicit masks of the shift count. For vector shifts, this
currently only works if the mask is applied before splatting the shift count,
but this should be addressed in a future commit. Resolves PR49655.
Differential Revision: https://reviews.llvm.org/D105600
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.
Differential Revision: https://reviews.llvm.org/D104797
This is a mechanical change. This actually also renames the
similarly named methods in the SmallString class, however these
methods don't seem to be used outside of the llvm subproject, so
this doesn't break building of the rest of the monorepo.
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/D95425
This patch adds TargetStackID::WasmLocal. This stack holds locations of
values that are only addressable by name -- not via a pointer to memory.
For the WebAssembly target, these objects are lowered to WebAssembly
local variables, which are managed by the WebAssembly run-time and are
not addressable by linear memory.
For the WebAssembly target IR indicates that an AllocaInst should be put
on TargetStackID::WasmLocal by putting it in the non-integral address
space WASM_ADDRESS_SPACE_WASM_VAR, with value 1. SROA will mostly lift
these allocations to SSA locals, but any alloca that reaches instruction
selection (usually in non-optimized builds) will be assigned the new
TargetStackID there. Loads and stores to those values are transformed
to new WebAssemblyISD::LOCAL_GET / WebAssemblyISD::LOCAL_SET nodes,
which then lower to the type-specific LOCAL_GET_I32 etc instructions via
tablegen patterns.
Differential Revision: https://reviews.llvm.org/D101140
This patch adds TargetStackID::WasmLocal. This stack holds locations of
values that are only addressable by name -- not via a pointer to memory.
For the WebAssembly target, these objects are lowered to WebAssembly
local variables, which are managed by the WebAssembly run-time and are
not addressable by linear memory.
For the WebAssembly target IR indicates that an AllocaInst should be put
on TargetStackID::WasmLocal by putting it in the non-integral address
space WASM_ADDRESS_SPACE_WASM_VAR, with value 1. SROA will mostly lift
these allocations to SSA locals, but any alloca that reaches instruction
selection (usually in non-optimized builds) will be assigned the new
TargetStackID there. Loads and stores to those values are transformed
to new WebAssemblyISD::LOCAL_GET / WebAssemblyISD::LOCAL_SET nodes,
which then lower to the type-specific LOCAL_GET_I32 etc instructions via
tablegen patterns.
Differential Revision: https://reviews.llvm.org/D101140
This patch adds TargetStackID::WasmLocal. This stack holds locations of
values that are only addressable by name -- not via a pointer to memory.
For the WebAssembly target, these objects are lowered to WebAssembly
local variables, which are managed by the WebAssembly run-time and are
not addressable by linear memory.
For the WebAssembly target IR indicates that an AllocaInst should be put
on TargetStackID::WasmLocal by putting it in the non-integral address
space WASM_ADDRESS_SPACE_WASM_VAR, with value 1. SROA will mostly lift
these allocations to SSA locals, but any alloca that reaches instruction
selection (usually in non-optimized builds) will be assigned the new
TargetStackID there. Loads and stores to those values are transformed
to new WebAssemblyISD::LOCAL_GET / WebAssemblyISD::LOCAL_SET nodes,
which then lower to the type-specific LOCAL_GET_I32 etc instructions via
tablegen patterns.
Differential Revision: https://reviews.llvm.org/D101140
DwarfDebug unconditionally assumes for all call instructions the 0th
operand is the callee operand, which seems to be true for other targets,
but not for WebAssembly. This adds `TargetInstrInfo::getCallOperand`
method whose default implementation returns `getOperand(0)` and makes
WebAssembly overrides it to use its own utility method to get the callee
operand.
This also fixes an existing bug in `WebAssembly::getCalleeOp`, which was
uncovered by this CL.
Reviewed By: dschuff, djtodoro
Differential Revision: https://reviews.llvm.org/D102978
`WebAssemblyDebugValueManager` does not currently handle
`DBG_VALUE_LIST`, which is a recent addition to LLVM. We tried to
nullify them within the constructor of `WebAssemblyDebugValueManager` in
D102589, but it made the class error-prone to use because it deletes
instructions within the constructor and thus invalidates existing
iterators within the BB, so the user of the class should take special
care not to use invalidated iterators. This actually caused a bug in
ExplicitLocals pass.
Instead of trying to fix ExplicitLocals pass to make the iterator usage
correct, which is possible but error-prone, this adds
NullifyDebugValueLists pass that nullifies all `DBG_VALUE_LIST`
instructions before we run WebAssembly specific passes in the backend.
We can remove this pass after we implement handlers for
`DBG_VALUE_LIST`s in `WebAssemblyDebugValueManager` and elsewhere.
Fixes https://github.com/emscripten-core/emscripten/issues/14255.
Reviewed By: dschuff
Differential Revision: https://reviews.llvm.org/D102999
Unlike normal loads these don't have an extension field, but we know
from TargetLowering whether these are sign-extending or zero-extending,
and so can optimise away unnecessary extensions.
This was noticed on RISC-V, where sign extensions in the calling
convention would result in unnecessary explicit extension instructions,
but this also fixes some Mips inefficiencies. PowerPC sees churn in the
tests as all the zero extensions are only for promoting 32-bit to
64-bit, but these zero extensions are still not optimised away as they
should be, likely due to i32 being a legal type.
This also simplifies the WebAssembly code somewhat, which currently
works around the lack of target-independent combines with some ugly
patterns that break once they're optimised away.
Re-landed with correct handling in ComputeNumSignBits for Tmp == VTBits,
where zero-extending atomics were incorrectly returning 0 rather than
the (slightly confusing) required return value of 1.
Re-landed again after D102819 fixed PowerPC to correctly zero-extend all
of its atomics as it claimed to do, since the combination of that bug
and this optimisation caused buildbot regressions.
Reviewed By: RKSimon, atanasyan
Differential Revision: https://reviews.llvm.org/D101342
__table_base is know 64-bit, since in LLVM it represents a function pointer offset
__table_base32 is a copy in wasm32 for use in elem init expr, since no truncation may be used there.
New reloc R_WASM_TABLE_INDEX_REL_SLEB64 added
Differential Revision: https://reviews.llvm.org/D101784
We have been handling filters and landingpads incorrectly all along. We
pass clauses' (catches') types to `__cxa_find_matching_catch` in JS glue
code, which returns the thrown pointer and sets the selector using
`setTempRet0()`.
We apparently have been doing the same for filters' (exception specs')
types; we pass them to `__cxa_find_matching_catch` just the same way as
clauses. And `__cxa_find_matching_catch` treats all given types as
clauses. So it is a little surprising; maybe we intended to do something
from the JS side and didn't end up doing?
So anyway, I don't think supporting exception specs in Emscripten EH is
a priority, but this can actually cause incorrect results for normal
catches when functions are inlined and the inlined spec type has a
parent-child relationship with the catch's type.
---
The below is an example of a bug that can happen when inlining and class
hierarchy is mixed. If you are busy you can skip this part:
```
struct A {};
struct B : A {};
void bar() throw (B) { throw B(); }
void foo() {
try {
bar();
} catch (A &) {
fputs ("Expected result\n", stdout);
}
}
```
In the unoptimized code, `bar`'s landingpad will have a filter for `B`
and `foo`'s landingpad will have a clause for `A`. But when `bar` is
inlined into `foo`, `foo`'s landingpad has both a filter for `B` and a
clause for `A`, and it passes the both types to
`__cxa_find_matching_catch`:
```
__cxa_find_matching_catch(typeinfo for B, typeinfo for A)
```
`__cxa_find_matching_catch` thinks both are clauses, and looks at the
first type `B`, which belongs to a filter. And the thrown type is `B`,
so it thinks the first type `B` is caught. But this makes it return an
incorrect selector, because it is supposed to catch the exception using
the second type `A`, which is a parent of `B`. As a result, the `foo` in
the example program above does not print "Expected result" but just
throws the exception to the caller. (This wouldn't have happened if `A`
and `B` are completely disjoint types, such as `float` and `int`)
Fixes https://bugs.llvm.org/show_bug.cgi?id=50357.
Reviewed By: dschuff, kripken
Differential Revision: https://reviews.llvm.org/D102795
WebAssemblyDebugValueManager class currently does not handle
DBG_VALUE_LIST instructions correctly for two reasons, which are
explained in https://bugs.llvm.org/show_bug.cgi?id=50361.
This effectively nullifies DBG_VALUE_LISTs in
WebAssemblyDebugValueManager so that the info will appear as "optimized
out" in debuggers but still be at least correct in the meantime.
Reviewed By: dschuff, jmorse
Differential Revision: https://reviews.llvm.org/D102589
When a stackified variable has an associated `DBG_VALUE` instruction,
DebugFixup pass adds a `DBG_VALUE` instruction after the stackified
value's last use to clear the variable's debug range info. But when the
last use instruction is a terminator, it can cause a verification
failure (when run with `-verify-machineinstrs`) because there are no
instructions allowed after a terminator.
For example:
```
%myvar = ...
DBG_VALUE target-index(wasm-operand-stack), $noreg, !"myvar", ...
BR_IF 0, %myvar, ...
DBG_VALUE $noreg, $noreg, !"myvar", ...
```
In this test, `%myvar` is stackified, so the first `DBG_VALUE`
instruction's first operand has changed to `wasm-operand-stack` to
denote it. And an additional `DBG_VALUE` instruction is added after its
last use, `BR_IF`, to signal variable `myvar` is not in the operand
stack anymore. But because the `DBG_VALUE` instruction is added after
the `BR_IF`, a terminator, it fails MachineVerifier.
`DBG_VALUE` instructions are used in `DbgEntityHistoryCalculator` to
compute value ranges to emit DWARF info, and it turns out the
`DbgEntityHistoryCalculator` terminates ranges at the end of a BB, so we
don't need to emit `DBG_VALUE` after a terminator.
Fixes https://bugs.llvm.org/show_bug.cgi?id=50175.
Reviewed By: dschuff
Differential Revision: https://reviews.llvm.org/D102309
In wasm64, the signatures of some library functions and global variables
defined in Emscripten change:
- `emscripten_longjmp`: `(i32, i32) -> ()` -> `(i64, i32) -> ()`
This changes because the first argument is the address of a memory
buffer. This in turn causes more changes below.
- `setThrew`: `(i32, i32) -> ()` -> `(i64, i32) -> ()`
`emscripten_longjmp` calls `setThrew` with the i64 buffer argument as
the first parameter.
- `__THREW__` (global var): `i32` to `i64`
`setThrew`'s first argument is set to this `__THREW__` variable, so it
should change to i64 as well.
- `testSetjmp`: `(i32, i32*, i32) -> (i32)` -> `(i64, i32*, i32) -> (i32)`
In the code transformation done in this pass, the value of `__THREW__`
is passed as the first parameter of `testSetjmp`.
This patch creates some helper functions to easily get types that become
different depending on the wasm32/wasm64, and uses them to change
various function signatures and code transformations. Also updates the
tests with WASM32/WASM64 check lines.
(Untested) Emscripten side patch: https://github.com/emscripten-core/emscripten/pull/14108
Reviewed By: aardappel
Differential Revision: https://reviews.llvm.org/D101985
We explicitly made it error out in D101403, out of a good intention that
the error message will make people less confusing. Turns out, we weren't
failing all cases of wasm EH + SjLj; only a few cases were failing and
our client was able to get around by fixing source code, but now we made
it fail for all cases, even the cases that previously succeeded fail,
which we didn't intend. This reverts that change.
Reviewed By: tlively
Differential Revision: https://reviews.llvm.org/D102364
As we have been missing support for WebAssembly globals on the IR level,
the lowering of WASM_SYMBOL_TYPE_GLOBAL to IR was incomplete. This
commit fleshes out the lowering support, lowering references to and
definitions of addrspace(1) values to correctly typed
WASM_SYMBOL_TYPE_GLOBAL symbols.
Depends on D101608.
Differential Revision: https://reviews.llvm.org/D101913
This patch adds support for WebAssembly globals in LLVM IR, representing
them as pointers to global values, in a non-default, non-integral
address space. Instruction selection legalizes loads and stores to
these pointers to new WebAssemblyISD nodes GLOBAL_GET and GLOBAL_SET.
Once the lowering creates the new nodes, tablegen pattern matches those
and converts them to Wasm global.get/set of the appropriate type.
Based on work by Paulo Matos in https://reviews.llvm.org/D95425.
Reviewed By: pmatos
Differential Revision: https://reviews.llvm.org/D101608
This change was originally landed in: 5000a1b4b9
It was reverted in: 061e071d8c
This change adds support for a new WASM_SEG_FLAG_STRINGS flag in
the object format which works in a similar fashion to SHF_STRINGS
in the ELF world.
Unlike the ELF linker this support is currently limited:
- No support for SHF_MERGE (non-string merging)
- Always do full tail merging ("lo" can be merged with "hello")
- Only support single byte strings (p2align 0)
Like the ELF linker merging is only performed at `-O1` and above.
This fixes part of https://bugs.llvm.org/show_bug.cgi?id=48828,
although crucially it doesn't not currently support debug sections
because they are not represented by data segments (they are custom
sections)
Differential Revision: https://reviews.llvm.org/D97657
This change adds support for a new WASM_SEG_FLAG_STRINGS flag in
the object format which works in a similar fashion to SHF_STRINGS
in the ELF world.
Unlike the ELF linker this support is currently limited:
- No support for SHF_MERGE (non-string merging)
- Always do full tail merging ("lo" can be merged with "hello")
- Only support single byte strings (p2align 0)
Like the ELF linker merging is only performed at `-O1` and above.
This fixes part of https://bugs.llvm.org/show_bug.cgi?id=48828,
although crucially it doesn't not currently support debug sections
because they are not represented by data segments (they are custom
sections)
Differential Revision: https://reviews.llvm.org/D97657
Unlike normal loads these don't have an extension field, but we know
from TargetLowering whether these are sign-extending or zero-extending,
and so can optimise away unnecessary extensions.
This was noticed on RISC-V, where sign extensions in the calling
convention would result in unnecessary explicit extension instructions,
but this also fixes some Mips inefficiencies. PowerPC sees churn in the
tests as all the zero extensions are only for promoting 32-bit to
64-bit, but these zero extensions are still not optimised away as they
should be, likely due to i32 being a legal type.
This also simplifies the WebAssembly code somewhat, which currently
works around the lack of target-independent combines with some ugly
patterns that break once they're optimised away.
Re-landed with correct handling in ComputeNumSignBits for Tmp == VTBits,
where zero-extending atomics were incorrectly returning 0 rather than
the (slightly confusing) required return value of 1.
Reviewed By: RKSimon, atanasyan
Differential Revision: https://reviews.llvm.org/D101342
- Removes the mention of fastcomp, which is deprecated.
- Some functions in Emscripten have moved from JS glue code to
compiler-rt/emscripten_setjmp.c and
compiler-rt/emscripten_exception_builtins.c. This fixes comments about
that.
Reviewed By: sbc100
Differential Revision: https://reviews.llvm.org/D101812
The WebAssembly SIMD intrinsics in wasm_simd128.h generally try not to require
any particular alignment for memory operations to be maximally flexible. For
builtin memory access functions and their corresponding LLVM IR intrinsics,
there's no way to set the expected alignment, so the best we can do is set the
alignment to 1 in the backend. This change means that the alignment hints in the
emitted code will no longer be incorrect when users use the intrinsics to access
unaligned data.
Differential Revision: https://reviews.llvm.org/D101850
This seems to have broken sanitizers, giving lots of
Assertion `NumBits <= MAX_INT_BITS && "bitwidth too large"' failed.
failures across multiple targets (currently X86 and PowerPC). Reverting
until I have a chance to reproduce and debug.
This reverts commit 6e876f9ded.
Unlike normal loads these don't have an extension field, but we know
from TargetLowering whether these are sign-extending or zero-extending,
and so can optimise away unnecessary extensions.
This was noticed on RISC-V, where sign extensions in the calling
convention would result in unnecessary explicit extension instructions,
but this also fixes some Mips inefficiencies. PowerPC sees churn in the
tests as all the zero extensions are only for promoting 32-bit to
64-bit, but these zero extensions are still not optimised away as they
should be, likely due to i32 being a legal type.
This also simplifies the WebAssembly code somewhat, which currently
works around the lack of target-independent combines with some ugly
patterns that break once they're optimised away.
Reviewed By: RKSimon, atanasyan
Differential Revision: https://reviews.llvm.org/D101342
We previously had an ISel pattern for i64x2.abs, but because the ISDNode was not
marked legal for v2i64, the instruction was not being selected.
Differential Revision: https://reviews.llvm.org/D101803
- Error out when both Emscripten EH and wasm EH are used together, i.e.,
both `-enable-emscripten-cxx-exceptions` and `-exception-model=wasm`
are given together. This will not happen if you use Emscripten, but
this can happen when you call `llc` manually with wrong set of
arguments.
- Currently we don't yet support using wasm EH with Emscripten SjLj.
Unlike `-enable-emscripten-cxx-exceptions` which is turned on only
when you use `emcc -s DISABLE_EXCEPTION_CATCHING=0`,
`-enable-emscripten-sjlj` is turned on by Emscripten by default. So we
error out only when it is turned on and `setjmp` or `longjmp` is
actually used.
Reviewed By: tlively
Differential Revision: https://reviews.llvm.org/D101403
Previously we used an i32 constant to store the saturation width, but i32 isn't
legal on RISCV64. This wasn't a big deal to fix, but it is extra work for the
type legalizer.
This patch uses a VTSDNode to store the type similar to SEXT_INREG. This makes
it opaque to the type legalizer.
Reviewed By: nikic
Differential Revision: https://reviews.llvm.org/D101262
Background:
CFGStackify's [[ 398f253400/llvm/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp (L1481-L1540) | fixEndsAtEndOfFunction ]] fixes block/loop/try's return
type when the end of function is unreachable and the function return
type is not void. So if a function returns i32 and `block`-`end` wraps the
whole function, i.e., the `block`'s `end` is the last instruction of the
function, the `block`'s return type should be i32 too:
```
block i32
...
end
end_function
```
If there are consecutive `end`s, this signature has to be propagate to
those blocks too, like:
```
block i32
...
block i32
...
end
end
end_function
```
This applies to `try`-`end` too:
```
try i32
...
catch
...
end
end_function
```
In case of `try`, we not only follow consecutive `end`s but also follow
`catch`, because for the type of the whole `try` to be i32, both `try`
and `catch` parts have to be i32:
```
try i32
...
block i32
...
end
catch
...
block i32
...
end
end
end_function
```
---
Previously we only handled consecutive `end`s or `end` before a `catch`.
But now we have `delegate`, which serves like `end` for
`try`-`delegate`. So we have to follow `delegate` too and mark its
corresponding `try` as i32 (the function's return type):
```
try i32
...
catch
...
try i32 ;; Here
...
delegate N
end
end_function
```
Reviewed By: tlively
Differential Revision: https://reviews.llvm.org/D101036
This adds support for YAML serialization of `Params` and `Results`
fields in `WebAssemblyMachineFunctionInfo`. Types are printed as `MVT`'s
string representation. This is for writing MIR tests easier.
The tests added are testing simple parsing and printing of `params` /
`results` fields under `machineFunctionInfo`.
Reviewed By: tlively
Differential Revision: https://reviews.llvm.org/D101029
This CL
1. Creates Utils/ directory under lib/Target/WebAssembly
2. Moves existing WebAssemblyUtilities.cpp|h into the Utils/ directory
3. Creates Utils/WebAssemblyTypeUtilities.cpp|h and put type
declarataions and type conversion functions scattered in various
places into this single place.
It has been suggested several times that it is not easy to share utility
functions between subdirectories (AsmParser, DIsassembler, MCTargetDesc,
...). Sometimes we ended up [[ https://reviews.llvm.org/D92840#2478863 | duplicating ]] the same function because of
this.
There are already other targets doing this: AArch64, AMDGPU, and ARM
have Utils/ subdirectory under their target directory.
This extracts the utility functions into a single directory Utils/ and
make them sharable among all passes in WebAssembly/ and its
subdirectories. Also I believe gathering all type-related conversion
functionalities into a single place makes it more usable. (Actually I
was working on another CL that uses various type conversion functions
scattered in multiple places, which became the motivation for this CL.)
Reviewed By: dschuff, aardappel
Differential Revision: https://reviews.llvm.org/D100995
This is just a cleanup of the very high level stuff. I'm sure there is
more to update here but I'll leave that to others and/or a followup.
Differential Revision: https://reviews.llvm.org/D100888
af7925b4dd added a custom DAG combine for recognizing fp-to-ints of
extract_subvectors that could be lowered to f64x2.convert_low_i32x4_{s,u}
instructions. This commit extends the combines to recognize equivalent
extract_subvectors of fp-to-ints as well.
Differential Revision: https://reviews.llvm.org/D100790
We previously used splats instead of v128.const to materialize vector constants
because V8 did not support v128.const. Now that V8 supports v128.const, we can
use v128.const instead. Although this increases code size, it should also
increase performance (or at least require fewer engine-side optimizations), so
it is an appropriate change to make.
Differential Revision: https://reviews.llvm.org/D100716
Use the target-independent @llvm.fptosi and @llvm.fptoui intrinsics instead.
This includes removing the instrinsics for i32x4.trunc_sat_zero_f64x2_{s,u},
which are now represented in IR as a saturating truncation to a v2i32 followed by
a concatenation with a zero vector.
Differential Revision: https://reviews.llvm.org/D100596
Removes the builtins and intrinsics used to opt in to using these instructions
and replaces them with normal ISel patterns now that they are no longer
prototypes.
Differential Revision: https://reviews.llvm.org/D100402
Add a custom DAG combine and ISD opcode for detecting patterns like
(uint_to_fp (extract_subvector ...))
before the extract_subvector is expanded to ensure that they will ultimately
lower to f64x2.convert_low_i32x4_{s,u} instructions. Since these instructions
are no longer prototypes and can now be produced via standard IR, this commit
also removes the target intrinsics and builtins that had been used to prototype
the instructions.
Differential Revision: https://reviews.llvm.org/D100425
Now that these instructions are no longer prototypes, we do not need to be
careful about keeping them opt-in and can use the standard LLVM infrastructure
for them. This commit removes the bespoke intrinsics we were using to represent
these operations in favor of the corresponding target-independent intrinsics.
The clang builtins are preserved because there is no standard way to easily
represent these operations in C/C++.
For consistency with the scalar codegen in the Wasm backend, the intrinsic used
to represent {f32x4,f64x2}.nearest is @llvm.nearbyint even though
@llvm.roundeven better captures the semantics of the underlying Wasm
instruction. Replacing our use of @llvm.nearbyint with use of @llvm.roundeven is
left to a potential future patch.
Differential Revision: https://reviews.llvm.org/D100411
In the final SIMD spec, there is only a single v128.any_true instruction, rather
than one for each lane interpretation because the semantics do not depend on the
lane interpretation.
Differential Revision: https://reviews.llvm.org/D100241
When lowering a BUILD_VECTOR SDNode, we choose among various possible vector
creation instructions in an attempt to minimize the total number of instructions
used. We previously considered using swizzles, consts, and splats, and this
patch adds shuffles as well. A common pattern that now lowers to shuffles is
when two 64-bit vectors are concatenated. Previously, concatenations generally
lowered to sequences of extract_lane and replace_lane instructions when they
could have been a single shuffle.
Differential Revision: https://reviews.llvm.org/D100018
wasm64 was missing DAG ISEL patterns for external symbol based global.get, but simply adding these analogous to the existing 32-bit versions doesn't work.
This is because we are conflating the 32-bit global index with the pointer represented by the external symbol, which for wasm32 happened to work.
The simplest fix is to pretend we have a 64-bit global index. This sounds incorrect, but is immaterial since once this index is stored as a MachineOperand it becomes 64-bit anyway (and has been all along). As such, the EmitInstrWithCustomInserter based implementation I experimented with become a no-op and no further changes in the C++ code are required.
Differential Revision: https://reviews.llvm.org/D99904
This is a followup to D98145: As far as I know, tracking of kill
flags in FastISel is just a compile-time optimization. However,
I'm not actually seeing any compile-time regression when removing
the tracking. This probably used to be more important in the past,
before FastRA was switched to allocate instructions in reverse
order, which means that it discovers kills as a matter of course.
As such, the kill tracking doesn't really seem to serve a purpose
anymore, and just adds additional complexity and potential for
errors. This patch removes it entirely. The primary changes are
dropping the hasTrivialKill() method and removing the kill
arguments from the emitFast methods. The rest is mechanical fixup.
Differential Revision: https://reviews.llvm.org/D98294
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
Removes the prototype builtin and intrinsic for i64x2.eq and implements that
instruction as well as the other i64x2 comparison instructions in the final SIMD
spec. Unsigned comparisons were not included in the final spec, so they still
need to be scalarized via a custom lowering.
Differential Revision: https://reviews.llvm.org/D99623
Currently needsStackRealignment returns false if canRealignStack returns false.
This means that the behavior of needsStackRealignment does not correspond to
it's name and description; a function might need stack realignment, but if it
is not possible then this function returns false. Furthermore,
needsStackRealignment is not virtual and therefore some backends have made use
of canRealignStack to indicate whether a function needs stack realignment.
This patch attempts to clarify the situation by separating them and introducing
new names:
- shouldRealignStack - true if there is any reason the stack should be
realigned
- canRealignStack - true if we are still able to realign the stack (e.g. we
can still reserve/have reserved a frame pointer)
- hasStackRealignment = shouldRealignStack && canRealignStack (not target
customisable)
Targets can now override shouldRealignStack to indicate that stack realignment
is required.
This change will make it easier in a future change to handle the case where we
need to realign the stack but can't do so (for example when the register
allocator creates an aligned spill after the frame pointer has been
eliminated).
Differential Revision: https://reviews.llvm.org/D98716
Change-Id: Ib9a4d21728bf9d08a545b4365418d3ffe1af4d87
When I updated the SIMD opcodes in f5764a8654, I accidentally missed updating
i8x16.popcnt. This patch fixes the omission.
Differential Revision: https://reviews.llvm.org/D99536
This patch changes the interface to take a RegisterKind, to indicate
whether the register bitwidth of a scalar register, fixed-width vector
register, or scalable vector register must be returned.
Reviewed By: paulwalker-arm
Differential Revision: https://reviews.llvm.org/D98874
This commit adds a full WasmTableType to MCSymbolWasm, differing from
the current situation (just an ElemType) in that it additionally records
a WasmLimits.
We add support for specifying the limits in .S files also, via the
following syntax variations:
.tabletype SYM, ELEMTYPE
.tabletype SYM, ELEMTYPE, MINSIZE
.tabletype SYM, ELEMTYPE, MINSIZE, MAXSIZE
Depends on D99186.
Differential Revision: https://reviews.llvm.org/D99191
Updates the names (e.g. widen => extend, saturate => sat) and opcodes of all
SIMD instructions to match the finalized SIMD spec. Deliberately does not change
the public interface in wasm_simd128.h yet; that will require more care.
Depends on D98466.
Differential Revision: https://reviews.llvm.org/D98676
Removes the instruction definitions, intrinsics, and builtins for qfma/qfms,
signselect, and prefetch instructions, which were not included in the final
WebAssembly SIMD spec.
Depends on D98457.
Differential Revision: https://reviews.llvm.org/D98466
Now that the WebAssembly SIMD specification is finalized and engines are
generally up-to-date, there is no need for a separate target feature for gating
SIMD instructions that engines have not implemented. With this change,
v128.const is now enabled by default with the simd128 target feature.
Differential Revision: https://reviews.llvm.org/D98457
This patch adds handling for DBG_VALUE_LIST in the MIR-passes (after
finalize-isel), excluding the debug liveness passes and DWARF emission. This
most significantly affects MachineSink, which now needs to consider all used
registers of a debug value when sinking, but for most passes this change is
simply replacing getDebugOperand(0) with an iteration over all debug operands.
Differential Revision: https://reviews.llvm.org/D92578
This `R_WASM_MEMORY_ADDR_SELFREL_I32` relocation represents an offset
between its relocating address and the symbol address. It's very similar
to `R_X86_64_PC32` but restricted to be used for only data segments.
```
S + A - P
```
A: Represents the addend used to compute the value of the relocatable
field.
P: Represents the place of the storage unit being relocated.
S: Represents the value of the symbol whose index resides in the
relocation entry.
Proposal: https://github.com/WebAssembly/tool-conventions/issues/162
Differential Revision: https://reviews.llvm.org/D96659
Rewrites test to use correct architecture triple; fixes incorrect
reference in SourceLevelDebugging doc; simplifies `spillReg` behaviour
so as to not be dependent on changes elsewhere in the patch stack.
This reverts commit d2000b45d0.
This is a case D97677 missed. When taking out remaining BBs that are
reachable from already-taken-out exceptions (because they are not
subexcptions but unwind destinations), I assumed the remaining BBs are
not EH pads, but they can be. For example,
```
try {
try {
throw 0;
} catch (int) { // (a)
}
} catch (int) { // (b)
}
try {
foo();
} catch (int) { // (c)
}
```
In this code, (b) is the unwind destination of (a) so its exception is
taken out of (a)'s exception, But even though the next try-catch is not
inside the first two-level try-catches, because the first try always
throws, its continuation BB is unreachable and the whole rest of the
function is dominated by EH pad (a), including EH pad (c). So after we
take out of (b)'s exception out of (a)'s, we also need to take out (c)'s
exception out of (a)'s, because (c) is reachable from (b).
This adds one more step before what we did for remaining BBs in D97677;
it traverses EH pads first to take subexceptions out of their incorrect
parent exception. It's the same thing as D97677, but because we can do
this before we add BBs to exceptions' sets, we don't need to fix sets
and only need to fix parent exception pointers.
Other changes are variable name changes (I changed `WE` -> `SrcWE`,
`UnwindWE` -> `DstWE` for clarity), some comment changes, and a drive-by
fix in a bug in a `LLVM_DEBUG` print statement.
Fixes https://github.com/emscripten-core/emscripten/issues/13588.
Reviewed By: dschuff
Differential Revision: https://reviews.llvm.org/D97929
Background:
Wasm EH, while using Windows EH (catchpad/cleanuppad based) IR, uses
Itanium-based libraries and ABIs with some modifications.
`__clang_call_terminate` is a wrapper generated in Clang's Itanium C++
ABI implementation. It contains this code, in C-style pseudocode:
```
void __clang_call_terminate(void *exn) {
__cxa_begin_catch(exn);
std::terminate();
}
```
So this function is a wrapper to call `__cxa_begin_catch` on the
exception pointer before termination.
In Itanium ABI, this function is called when another exception is thrown
while processing an exception. The pointer for this second, violating
exception is passed as the argument of this `__clang_call_terminate`,
which calls `__cxa_begin_catch` with that pointer and calls
`std::terminate` to terminate the program.
The spec (https://libcxxabi.llvm.org/spec.html) for `__cxa_begin_catch`
says,
```
When the personality routine encounters a termination condition, it
will call __cxa_begin_catch() to mark the exception as handled and then
call terminate(), which shall not return to its caller.
```
In wasm EH's Clang implementation, this function is called from
cleanuppads that terminates the program, which we also call terminate
pads. Cleanuppads normally don't access the thrown exception and the
wasm backend converts them to `catch_all` blocks. But because we need
the exception pointer in this cleanuppad, we generate
`wasm.get.exception` intrinsic (which will eventually be lowered to
`catch` instruction) as we do in the catchpads. But because terminate
pads are cleanup pads and should run even when a foreign exception is
thrown, so what we have been doing is:
1. In `WebAssemblyLateEHPrepare::ensureSingleBBTermPads()`, we make sure
terminate pads are in this simple shape:
```
%exn = catch
call @__clang_call_terminate(%exn)
unreachable
```
2. In `WebAssemblyHandleEHTerminatePads` pass at the end of the
pipeline, we attach a `catch_all` to terminate pads, so they will be in
this form:
```
%exn = catch
call @__clang_call_terminate(%exn)
unreachable
catch_all
call @std::terminate()
unreachable
```
In `catch_all` part, we don't have the exception pointer, so we call
`std::terminate()` directly. The reason we ran HandleEHTerminatePads at
the end of the pipeline, separate from LateEHPrepare, was it was
convenient to assume there was only a single `catch` part per `try`
during CFGSort and CFGStackify.
---
Problem:
While it thinks terminate pads could have been possibly split or calls
to `__clang_call_terminate` could have been duplicated,
`WebAssemblyLateEHPrepare::ensureSingleBBTermPads()` assumes terminate
pads contain no more than calls to `__clang_call_terminate` and
`unreachable` instruction. I assumed that because in LLVM very limited
forms of transformations are done to catchpads and cleanuppads to
maintain the scoping structure. But it turned out to be incorrect;
passes can merge cleanuppads into one, including terminate pads, as long
as the new code has a correct scoping structure. One pass that does this
I observed was `SimplifyCFG`, but there can be more. After this
transformation, a single cleanuppad can contain any number of other
instructions with the call to `__clang_call_terminate` and can span many
BBs. It wouldn't be practical to duplicate all these BBs within the
cleanuppad to generate the equivalent `catch_all` blocks, only with
calls to `__clang_call_terminate` replaced by calls to `std::terminate`.
Unless we do more complicated transformation to split those calls to
`__clang_call_terminate` into a separate cleanuppad, it is tricky to
solve.
---
Solution (?):
This CL just disables the generation and use of `__clang_call_terminate`
and calls `std::terminate()` directly in its place.
The possible downside of this approach can be, because the Itanium ABI
intended to "mark" the violating exception handled, we don't do that
anymore. What `__cxa_begin_catch` actually does is increment the
exception's handler count and decrement the uncaught exception count,
which in my opinion do not matter much given that we are about to
terminate the program anyway. Also it does not affect info like stack
traces that can be possibly shown to developers.
And while we use a variant of Itanium EH ABI, we can make some
deviations if we choose to; we are already different in that in the
current version of the EH spec we don't support two-phase unwinding. We
can possibly consider a more complicated transformation later to
reenable this, but I don't think that has high priority.
Changes in this CL contains:
- In Clang, we don't generate a call to `wasm.get.exception()` intrinsic
and `__clang_call_terminate` function in terminate pads anymore; we
simply generate calls to `std::terminate()`, which is the default
implementation of `CGCXXABI::emitTerminateForUnexpectedException`.
- Remove `WebAssembly::ensureSingleBBTermPads() function and
`WebAssemblyHandleEHTerminatePads` pass, because terminate pads are
already `catch_all` now (because they don't need the exception
pointer) and we don't need these transformations anymore.
- Change tests to use `std::terminate` directly. Also removes tests that
tested `LateEHPrepare::ensureSingleBBTermPads` and
`HandleEHTerminatePads` pass.
- Drive-by fix: Add some function attributes to EH intrinsic
declarations
Fixes https://github.com/emscripten-core/emscripten/issues/13582.
Reviewed By: dschuff, tlively
Differential Revision: https://reviews.llvm.org/D97834
This patch adds a new instruction that can represent variadic debug values,
DBG_VALUE_VAR. This patch alone covers the addition of the instruction and a set
of basic code changes in MachineInstr and a few adjacent areas, but does not
correctly handle variadic debug values outside of these areas, nor does it
generate them at any point.
The new instruction is similar to the existing DBG_VALUE instruction, with the
following differences: the operands are in a different order, any number of
values may be used in the instruction following the Variable and Expression
operands (these are referred to in code as “debug operands”) and are indexed
from 0 so that getDebugOperand(X) == getOperand(X+2), and the Expression in a
DBG_VALUE_VAR must use the DW_OP_LLVM_arg operator to pass arguments into the
expression.
The new DW_OP_LLVM_arg operator is only valid in expressions appearing in a
DBG_VALUE_VAR; it takes a single argument and pushes the debug operand at the
index given by the argument onto the Expression stack. For example the
sub-expression `DW_OP_LLVM_arg, 0` has the meaning “Push the debug operand at
index 0 onto the expression stack.”
Differential Revision: https://reviews.llvm.org/D82363
The WebAssembly text and binary formats have different operand orders
for the "type" and "table" fields of call_indirect (and
return_call_indirect). In LLVM we use the binary order for the MCInstr,
but when we produce or consume the text format we should use the text
order. For compilation units targetting WebAssembly 1.0 (without the
reference types feature), we omit the table operand entirely.
Differential Revision: https://reviews.llvm.org/D97761
This fixes two bugs in `WebAssemblyExceptionInfo` grouping, created by
D97247. These two bugs are not easy to split into two different CLs,
because tests that fail for one also tend to fail for the other.
- In D97247, when fixing `ExceptionInfo` grouping by taking out
the unwind destination' exception from the unwind src's exception, we
just iterated the BBs in the function order, but this was incorrect;
this changes it to dominator tree preorder. Please refer to the
comments in the code for the reason and an example.
- After this subexception-taking-out fix, there still can be remaining
BBs we have to take out. When Exception B is taken out of Exception A
(because EHPad B is the unwind destination of EHPad A), there can
still be BBs within Exception A that are reachable from Exception B,
which also should be taken out. Please refer to the comments in the
code for more detailed explanation on why this can happen. To make
this possible, this splits `WebAssemblyException::addBlock` into two
parts: adding to a set and adding to a vector. We need to iterate on
BBs within a `WebAssemblyException` to fix this, so we add BBs to sets
first. But we add BBs to vectors later after we fix all incorrectness
because deleting BBs from vectors is expensive. I considered removing
the vector from `WebAssemblyException`, but it was not easy because
this class has to maintain a similar interface with `MachineLoop` to
be wrapped into a single interface `SortRegion`, which is used in
CFGSort.
Other misc. drive-by fixes:
- Make `WebAssemblyExceptionInfo` do not even run when wasm EH is not
used or the function doesn't have any EH pads, not to waste time
- Add `LLVM_DEBUG` lines for easy debugging
- Fix `preds` comments in cfg-stackify-eh.ll
- Fix `__cxa_throw`'s signature in cfg-stackify-eh.ll
Fixes https://github.com/emscripten-core/emscripten/issues/13554.
Reviewed By: dschuff, tlively
Differential Revision: https://reviews.llvm.org/D97677
In `LateEHPrepare::addCatchAlls`, the current code tries to get the
iterator's debug info even when it is `MachineBasicBlock::end()`. This
fixes the bug by adding empty debug info instead in that case.
Reviewed By: tlively
Differential Revision: https://reviews.llvm.org/D97679
If the reference-types feature is enabled, call_indirect will explicitly
reference its corresponding function table via TABLE_NUMBER
relocations against a table symbol.
Also, as before, address-taken functions can also cause the function
table to be created, only with reference-types they additionally cause a
symbol table entry to be emitted.
Differential Revision: https://reviews.llvm.org/D90948
D97247 added the reverse mapping from unwind destination to their
source, but it had a critical bug; sources can be multiple, because
multiple BBs can have a single BB as their unwind destination.
This changes `WasmEHFuncInfo::getUnwindSrc` to `getUnwindSrcs` and makes
it return a vector rather than a single BB. It does not return the const
reference to the existing vector but creates a new vector because
`WasmEHFuncInfo` stores not `BasicBlock*` or `MachineBasicBlock*` but
`PointerUnion` of them. Also I hoped to unify those methods for
`BasicBlock` and `MachineBasicBlock` into one using templates to reduce
duplication, but failed because various usages require `BasicBlock*` to
be `const` but it's hard to make it `const` for `MachineBasicBlock`
usages.
Fixes https://github.com/emscripten-core/emscripten/issues/13514.
(More precisely, fixes
https://github.com/emscripten-core/emscripten/issues/13514#issuecomment-784708744)
Reviewed By: dschuff, tlively
Differential Revision: https://reviews.llvm.org/D97583
Use `APInt` to convert a 32-bit or 64-bit immediate to an `APFloat` rather than
`bit_cast` to a `float` or `double` to avoid going through host floating-point and
potentially changing the bit pattern of NaNs.
Differential Revision: https://reviews.llvm.org/D97490
This is a case D97178 tried to solve but missed. D97178 could not handle
the case when
multiple consecutive delegates are generated:
- Before:
```
block
br (a)
try
catch
end_try
end_block
<- (a)
```
- After
```
block
br (a)
try
...
try
try
catch
end_try
<- (a)
delegate
delegate
end_block
<- (b)
```
(The `br` should point to (b) now)
D97178 assumed `end_block` exists two BBs later than `end_try`, because
it assumed the order as `end_try` BB -> `delegate` BB -> `end_block` BB.
But it turned out there can be multiple `delegate`s in between. This
patch changes the logic so we just search from `end_try` BB until we
find `end_block`.
Fixes https://github.com/emscripten-core/emscripten/issues/13515.
(More precisely, fixes
https://github.com/emscripten-core/emscripten/issues/13515#issuecomment-784711318.)
Reviewed By: dschuff, tlively
Differential Revision: https://reviews.llvm.org/D97569
This CL is not big but contains changes that span multiple analyses and
passes. This description is very long because it tries to explain basics
on what each pass/analysis does and why we need this change on top of
that. Please feel free to skip parts that are not necessary for your
understanding.
---
`WasmEHFuncInfo` contains the mapping of <EH pad, the EH pad's next
unwind destination>. The value (unwind dest) here is where an exception
should end up when it is not caught by the key (EH pad). We record this
info in WasmEHPrepare to fix catch mismatches, because the CFG itself
does not have this info. A CFG only contains BBs and
predecessor-successor relationship between them, but in `WasmEHFuncInfo`
the unwind destination BB is not necessarily a successor or the key EH
pad BB. Their relationship can be intuitively explained by this C++ code
snippet:
```
try {
try {
foo();
} catch (int) { // EH pad
...
}
} catch (...) { // unwind destination
}
```
So when `foo()` throws, it goes to `catch (int)` first. But if it is not
caught by it, it ends up in the next unwind destination `catch (...)`.
This unwind destination is what you see in `catchswitch`'s
`unwind label %bb` part.
---
`WebAssemblyExceptionInfo` groups exceptions so that they can be sorted
continuously together in CFGSort, as we do for loops. What this analysis
does is very simple: it creates a single `WebAssemblyException` per EH
pad, and all BBs that are dominated by that EH pad are included in this
exception. We also identify subexception relationship in this way: if
EHPad A domiantes EHPad B, EHPad B's exception is a subexception of
EHPad A's exception.
This simple rule turns out to be incorrect in some cases. In
`WasmEHFuncInfo`, if EHPad A's unwind destination is EHPad B, it means
semantically EHPad B should not be included in EHPad A's exception,
because it does not make sense to rethrow/delegate to an inner scope.
This is what happened in CFGStackify as a result of this:
```
try
try
catch
... <- %dest_bb is among here!
end
delegate %dest_bb
```
So this patch adds a phase in `WebAssemblyExceptionInfo::recalculate` to
make sure excptions' unwind destinations are not subexceptions of
their unwind sources in `WasmEHFuncInfo`.
But this alone does not prevent `dest_bb` in the example above from
being sorted within the inner `catch`'s exception, even if its exception
is not a subexception of that `catch`'s exception anymore, because of
how CFGSort works, which will be explained below.
---
CFGSort places BBs within the same `SortRegion` (loop or exception)
continuously together so they can be demarcated with `loop`-`end_loop`
or `catch`-`end_try` in CFGStackify.
`SortRegion` is a wrapper for one of `MachineLoop` or
`WebAssemblyException`. `SortRegionInfo` already does some complicated
things because there discrepancies between those two data structures.
`WebAssemblyException` is what we control, and it is defined as an EH
pad as its header and BBs dominated by the header as its BBs (with a
newly added exception of unwind destinations explained in the previous
paragraph). But `MachineLoop` is an LLVM data structure and uses the
standard loop detection algorithm. So by the algorithm, BBs that are 1.
dominated by the loop header and 2. have a path back to its header.
Because of the second condition, many BBs that are dominated by the loop
header are not included in the loop. So BBs that contain `return` or
branches to outside of the loop are not technically included in
`MachineLoop`, but they can be sorted together with the loop with no
problem.
Maybe to relax the condition, in CFGSort, when we are in a `SortRegion`
we allow sorting of not only BBs that belong to the current innermost
region but also BBs that are by the current region header.
(This was written this way from the first version written by Dan, when
only loops existed.) But now, we have cases in exceptions when EHPad B
is the unwind destination for EHPad A, even if EHPad B is dominated by
EHPad A it should not be included in EHPad A's exception, and should not
be sorted within EHPad A.
One way to make things work, at least correctly, is change `dominates`
condition to `contains` condition for `SortRegion` when sorting BBs, but
this will change compilation results for existing non-EH code and I
can't be sure it will not degrade performance or code size. I think it
will degrade performance because it will force many BBs dominated by a
loop, which don't have the path back to the header, to be placed after
the loop and it will likely to create more branches and blocks.
So this does a little hacky check when adding BBs to `Preferred` list:
(`Preferred` list is a ready list. CFGSort maintains ready list in two
priority queues: `Preferred` and `Ready`. I'm not very sure why, but it
was written that way from the beginning. BBs are first added to
`Preferred` list and then some of them are pushed to `Ready` list, so
here we only need to guard condition for `Preferred` list.)
When adding a BB to `Preferred` list, we check if that BB is an unwind
destination of another BB. To do this, this adds the reverse mapping,
`UnwindDestToSrc`, and getter methods to `WasmEHFuncInfo`. And if the BB
is an unwind destination, it checks if the current stack of regions
(`Entries`) contains its source BB by traversing the stack backwards. If
we find its unwind source in there, we add the BB to its `Deferred`
list, to make sure that unwind destination BB is added to `Preferred`
list only after that region with the unwind source BB is sorted and
popped from the stack.
---
This does not contain a new test that crashes because of this bug, but
this fix changes the result for one of existing test case. This test
case didn't crash because it fortunately didn't contain `delegate` to
the incorrectly placed unwind destination BB.
Fixes https://github.com/emscripten-core/emscripten/issues/13514.
Reviewed By: dschuff, tlively
Differential Revision: https://reviews.llvm.org/D97247
This adds support for serialization of `WasmEHFuncInfo`, in the form of
<Source BB Number, Unwind destination BB number>. To make YAML mapping
work, we needed to make a copy of the existing `SrcToUnwindDest` map
within `yaml::WebAssemblyMachineFunctionInfo`.
It was hard to add EH MIR tests for CFGStackify because `WasmEHFuncInfo`
could not be read from test MIR files. This adds the serialization
support for that to make EH MIR tests easier.
Reviewed By: dschuff
Differential Revision: https://reviews.llvm.org/D97174
This renames variable and method names in `WasmEHFuncInfo` class to be
simpler and clearer. For example, unwind destinations are EH pads by
definition so it doesn't necessarily need to be included in every method
name. Also I am planning to add the reverse mapping in a later CL,
something like `UnwindDestToSrc`, so this renaming will make meanings
clearer.
Reviewed By: dschuff
Differential Revision: https://reviews.llvm.org/D97173
If the reference-types feature is enabled, call_indirect will explicitly
reference its corresponding function table via `TABLE_NUMBER`
relocations against a table symbol.
Also, as before, address-taken functions can also cause the function
table to be created, only with reference-types they additionally cause a
symbol table entry to be emitted.
We abuse the used-in-reloc flag on symbols to indicate which tables
should end up in the symbol table. We do this because unfortunately
older wasm-ld will carp if it see a table symbol.
Differential Revision: https://reviews.llvm.org/D90948
Usually `EH_LABEL`s are placed in
- Before an `invoke` (which becomes calls in the backend)
- After an `invoke`
- At the start of an EH pad
I don't know exactly why, but I noticed there are cases of multiple, not
a single, `EH_LABEL` instructions in the beginning of an EH pad. In that
case `global.set` instruction placed to restore `__stack_pointer` ended
up between two `EH_LABEL` instructions before `CATCH`. It should follow
after the `EH_LABEL`s and `CATCH`. This CL fixes that case.
Reviewed By: dschuff
Differential Revision: https://reviews.llvm.org/D96970
Updating `EHPadStack` with respect to `TRY` and `CATCH` instructions
have to be done after checking all other conditions, not before. Because
we did this before checking other conditions, when we encounter `TRY`
and we want to record the current mismatching range, we already have
popped up the entry from `EHPadStack`, which we need to access to record
the range.
The `baz` call in the added test needs try-delegate because the previous
TRY marker placement for `quux` was placed before `baz`, because `baz`'s
return value was stackified in RegStackify. If this wasn't stackified
this try-delegate is not strictly necessary, but at the moment it is not
easy to identify cases like this. I plan to transfer `nounwind`
attributes from the LLVM IR to prevent cases like this. The call in the
test does not have `unwind` attribute in order to test this bug, but in
many cases of this pattern the previous call has `nounwind` attribute.
Reviewed By: tlively
Differential Revision: https://reviews.llvm.org/D96711
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/137https://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
I previously assumed `delegate`'s immediate argument computation
followed a different rule than that of branches, but we agreed to make
it the same
(https://github.com/WebAssembly/exception-handling/issues/146). This
removes the need for a separate `DelegateStack` in both CFGStackify and
InstPrinter.
When computing the immediate argument, we use a different function for
`delegate` computation because in MIR `DELEGATE`'s instruction's
destination is the destination catch BB or delegate BB, and when it is a
catch BB, we need an additional step of getting its corresponding `end`
marker.
Reviewed By: tlively, dschuff
Differential Revision: https://reviews.llvm.org/D96525
Enable partial and runtime unrolling with a threshold of 30, which
was derived from a large number of kernels running on node and
wasmtime for amd64 and aarch64.
Unrolling is enabled by default at -O2 and -O3 and is disabled at
-Oz and -Os. Compiling with -Os is recommended if the wasm binary
size is the most important factor.
Differential Revision: https://reviews.llvm.org/D95125
Fixes TableGen parser errors reported by D95874 due to incompatible types being used on multiclass templates.
Differential Revision: https://reviews.llvm.org/D96205
This updates InstPrinter and AsmParser for `delegate` and `catch_all`
instructions. Both will reject programs with multiple `catch_all`s per a
single `try`. And InstPrinter uses `EHInstStack` to figure out whether
to print catch label comments: It does not print catch label comments
for second `catch` or `catch_all` in a `try`.
Reviewed By: aardappel
Differential Revision: https://reviews.llvm.org/D94051
Terminate pads, cleanup pads with `__clang_call_terminate` call, have
`catch` instruction in them because `__clang_call_terminate` takes an
exception pointer. But these terminate pads should be reached also in
case of foreign exception. So this pass attaches an additional
`catch_all` BB after every terminate pad BB, with a call to
`std::terminate`.
Reviewed By: tlively
Differential Revision: https://reviews.llvm.org/D94050
This fixes unwind destination mismatches caused by 'catch'es, which
occur when a foreign exception is not caught by the nearest `catch` and
the next outer `catch` is not the catch it should unwind to, or the next
unwind destination should be the caller instead. 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.
Reviewed By: tlively
Differential Revision: https://reviews.llvm.org/D94049
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
We used to require .functype immediately follows the label it sets the type of, but not all Clang output follows this rule.
Now we simply allow it on any symbol, but only assume its a function start for a defined symbol, which is simpler and more general.
Fixes (part of) https://bugs.llvm.org/show_bug.cgi?id=49036
Differential Revision: https://reviews.llvm.org/D96165
As mentioned in TODO comment, casting double to float causes NaNs to change bits.
To avoid the change, this patch adds support for single-floating-point immediate value on MachineCode.
Patch by Yuta Saito.
Differential Revision: https://reviews.llvm.org/D77384
Various *TargetStreamer.h need formatted_raw_ostream but rely on a
forward declaration of formatted_raw_ostream in MCStreamer.h. This
patch adds forward declarations right in *TargetStreamer.h.
While we are at it, this patch removes the one in MCStreamer.h, where
it is unnecessary.
This reverts commit 418df4a6ab.
This change broke emscripten tests, I believe because it started
generating 5-byte a wide table index in the call_indirect instruction.
Neither v8 nor wabt seem to be able to handle that. The spec
currently says that this is single 0x0 byte and:
"In future versions of WebAssembly, the zero byte occurring in the
encoding of the call_indirectcall_indirect instruction may be used to
index additional tables."
So we need to revisit this change. For backwards compat I guess
we need to guarantee that __indirect_function_table is always at
address zero. We could also consider making this a single-byte
relocation with and assert if have more than 127 tables (for now).
Differential Revision: https://reviews.llvm.org/D95005
This patch changes to make call_indirect explicitly refer to the
corresponding function table, residualizing TABLE_NUMBER relocs against
it.
With this change, wasm-ld now sees all references to tables, and can
link multiple tables.
Differential Revision: https://reviews.llvm.org/D90948
After placing markers, we removed some unnecessary branches, but it only
handled the simplest case. This makes more unnecessary branches to be
removed.
Reviewed By: dschuff, tlively
Differential Revision: https://reviews.llvm.org/D94047
Updating `ScopeTops` is something we frequently do in CFGStackify, so
this factors it out as a function. This also makes a few utility
functions templated so that they are not dependent on input vector
types and simplifies function parameters.
Reviewed By: tlively
Differential Revision: https://reviews.llvm.org/D94046
This ensures every single terminate pad is a single BB in the form of:
```
%exn = catch $__cpp_exception
call @__clang_call_terminate(%exn)
unreachable
```
This is a preparation for HandleEHTerminatePads pass, which will be
added in a later CL and will run after CFGStackify. That pass duplicates
terminate pads with a `catch_all` instruction, and duplicating it
becomes simpler if we can ensure every terminate pad is a single BB.
Reviewed By: dschuff, tlively
Differential Revision: https://reviews.llvm.org/D94045
This removes unreachable EH pads in LateEHPrepare. This is not for
optimization but for preparation for CFGStackify. In CFGStackify, we
determine where to place `try` marker by computing the nearest common
dominator of all predecessors of an EH pad, but when an EH pad does not
have a predecessor, it becomes tricky. We can insert an empty dummy BB
before the EH pad and place the `try` there, but removing unreachable EH
pads is simpler.
This moves an existing exception label test from eh-label.mir to
exception.mir and adds a new test there.
This also adds some comments to existing methods.
Reviewed By: dschuff, tlively
Differential Revision: https://reviews.llvm.org/D94044
- Updates InstPrinter to handle `catch_all`.
- Makes `rethrow` condition an early exit from the function to make the
rest simpler.
- Unify label and catch counters. They don't need to be counted
separately and this will help `delegate` instruction later.
- Removes `LastSeenEHInst` field. This was first introduced to handle
when there are more than one `catch` blocks per `try`, but this was
not implemented correctly and not being used at the moment anyway.
- Reenables all tests in cfg-stackify-eh.ll that don't deal with unwind
destination mismatches, which will be handled in a later CL.
Reviewed By: dschuff, tlively, aardappel
Differential Revision: https://reviews.llvm.org/D94043
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
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
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
`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
A struct in C passed by value did not get debug information. Such values are currently
lowered to a Wasm local even in -O0 (not to an alloca like on other archs), which becomes
a Target Index operand (TI_LOCAL). The DWARF writing code was not emitting locations
in for TI's specifically if the location is a single range (not a list).
In addition, the ExplicitLocals pass which removes the ARGUMENT pseudo instructions did
not update the associated DBG_VALUEs, and couldn't even find these values since the code
assumed such instructions are adjacent, which is not the case here.
Also fixed asm printing of TIs needed by a test.
Differential Revision: https://reviews.llvm.org/D94140
Make the sequence of passes to select and rewrite instructions to
physical registers be a target callback. This is to prepare to allow
targets to split register allocation into multiple phases.
For wasm-ld table linking work to proceed, object files should indicate
if they use an indirect function table. In the future this will be done
by the usual symbols and relocations mechanism, but until that support
lands in the linker, the presence of an `__indirect_function_table` in
the object file's import section shows that the object file needs an
indirect function table.
Prior to https://reviews.llvm.org/D91637, this condition was met by all
object files residualizing an `__indirect_function_table` import.
Since https://reviews.llvm.org/D91637, the intention has been that only
those object files needing an indirect function table would have the
`__indirect_function_table` import. However, we missed the case of
object files which use the table via `call_indirect` but which
themselves do not declare any indirect functions.
This changeset makes it so that when we lower a call to `call_indirect`,
that we ensure that a `__indirect_function_table` symbol is present and
that it will be propagated to the linker.
A followup patch will revise this mechanism to make an explicit link
between `call_indirect` and its associated indirect function table; see
https://reviews.llvm.org/D90948.
Differential Revision: https://reviews.llvm.org/D92840
As proposed in https://github.com/WebAssembly/simd/pull/380. This commit makes
the new instructions available only via clang builtins and LLVM intrinsics to
make their use opt-in while they are still being evaluated for inclusion in the
SIMD proposal.
Depends on D93771.
Differential Revision: https://reviews.llvm.org/D93775
This commit is a follow-on to c2c2e9119e73, using the `Vec` records introduced
in that commit in the rest of the SIMD instruction definitions. Also removes
unnecessary types in output patterns.
Differential Revision: https://reviews.llvm.org/D93771
Zhi An Ng