Summary:
The LTO pass and LLD linker have logic in them that forces extraction
and prevent internalization of needed runtime calls. However, these
currently take all RTLibcalls into account, even if the target does not
support them. The target opts-out of a libcall if it sets its name to
nullptr. This patch pulls this logic out into a class in the header so
that LTO / lld can use it to determine if a symbol actually needs to be
kept.
This is important for targets like AMDGPU that want to be able to use
`lld` to perform the final link step, but does not want the overhead of
uncalled functions. (This adds like a second to the link time trivially)
The wasm backend fetches the tan runtime lib call in
`llvm/include/llvm/IR/RuntimeLibcalls.def` via `StaticLibcallNameMap()`,
but ignores the runtime function because a function sinature mapping is
not specified in RuntimeLibcallSignatureTable(). The fix is to specify
the function signatures for float32-128.
This is a fix for a build break reported on PR
https://github.com/llvm/llvm-project/pull/94559#issuecomment-2159923215.
Multivalue feature of WebAssembly has been standardized for several
years now. I think it makes sense to be able to enable it in the feature
section by default for our clang/llvm-produced binaries so that the
multivalue feature can be used as necessary when necessary within our
toolchain and also when running other optimizers (e.g. wasm-opt) after
the LLVM code generation.
But some WebAssembly toolchains, such as Emscripten, do not provide both
mulvalue-returning and not-multivalue-returning versions of libraries.
Also allowing the uses of multivalue in the features section does not
necessarily mean we generate them whenever we can to the fullest, which
is a different code generation / optimization option.
So this makes the lowering of multivalue returns conditional on the use
of 'experimental-mv' target ABI. This ABI is turned off by default and
turned on by passing `-Xclang -target-abi -Xclang experimental-mv` to
`clang`, or `-target-abi experimental-mv` to `clang -cc1` or `llc`.
But the purpose of this PR is not tying the multivalue lowering to this
specific 'experimental-mv'. 'experimental-mv' is just one multivalue ABI
we currently have, and it is still experimental, meaning it is not very
well optimized or tuned for performance. (e.g. it does not have the
limitation of the max number of multivalue-lowered values, which can be
detrimental to performance.) We may change the name of this ABI, or
improve it, or add a new multivalue ABI in the future. Also I heard that
WASI is planning to add their multivalue ABI soon. So the plan is,
whenever any one of multivalue ABIs is enabled, we enable the lowering
of multivalue returns in the backend. We currently have only
'experimental-mv' in the repo so we only check for that in this PR.
Related past discussions:
#82714https://github.com/WebAssembly/tool-conventions/pull/223#issuecomment-2008298652
These are Wasm only functions so they are better be within `WebAssembly`
namespace rather than the `llvm` namespace which includes the whole
LLVM.
Also this removes `extern` keywords which are not strictly necessary.
This reverts commit 6e6bf9f81756ba6655b4eea8dc45469a47f89b39.
It turned out the multivalue feature had active outside users and it
could cause some disruptions to them, so I'd like to investigate more
about the workarounds before doing this.
We plan to enable multivalue in the features section soon (#80923) for
other reasons, such as the feature having been standardized for many
years and other features being developed (e.g. EH) depending on it. This
is separate from enabling Clang experimental multivalue ABI (`-Xclang
-target-abi -Xclang experimental-mv`), but it turned out we generate
some multivalue code in the backend as well if it is enabled in the
features section.
Given that our backend multivalue generation still has not been much
used nor tested, and enabling the feature in the features section can be
a separate decision from how much multialue (including none) we decide
to generate for now, I'd like to temporarily disable the actual
generation of multivalue in our backend. To do that, this adds an
internal flag `-wasm-emit-multivalue` that defaults to false. All our
existing multivalue tests can use this to test multivalue code. This
flag can be removed later when we are confident the multivalue
generation is well tested.
llvm.ldexp.* intrinsics were recently added to LLVM, which means
wasm now needs to know the signatures of the corresponding libcalls.
Differential Revision: https://reviews.llvm.org/D152385Fixes: #63164
Since clang started emitting roundeven intrinsics in a7d6593a0a17, they would
cause a crash in the WebAssembly backend because it did not know the roundeven
library function signatures. Fix the crash by adding the signatures.
Differential Revision: https://reviews.llvm.org/D147476
fixed: #59095
Update libcall signatures to use multivalue return rather than returning via a pointer
when the multivalue features is enabled in the WebAssembly backend.
Reviewed By: tlively
Differential Revision: https://reviews.llvm.org/D146271
(Reapply after revert in e9ce1a588030d8d4004f5d7e443afe46245e9a92 due to
Fuchsia test failures. Removed changes in lib/ExecutionEngine/ other
than error categories, to be checked in more detail and reapplied
separately.)
Bulk remove many of the more trivial uses of ManagedStatic in the llvm
directory, either by defining a new getter function or, in many cases,
moving the static variable directly into the only function that uses it.
Differential Revision: https://reviews.llvm.org/D129120
Bulk remove many of the more trivial uses of ManagedStatic in the llvm
directory, either by defining a new getter function or, in many cases,
moving the static variable directly into the only function that uses it.
Differential Revision: https://reviews.llvm.org/D129120
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
Summary:
Fixes a crash in the backend where optimizations produce calls to the
cbrt runtime functions. Fixes PR 44227.
Reviewers: aheejin
Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D74259
Summary:
This always just used the same libcall as unordered, but the comparison predicate was different. This change appears to have been made when targets were given the ability to override the predicates. Before that they were hardcoded into the type legalizer. At that time we never inverted predicates and we handled ugt/ult/uge/ule compares by emitting an unordered check ORed with a ogt/olt/oge/ole checks. So only ordered needed an inverted predicate. Later ugt/ult/uge/ule were optimized to only call a single libcall and invert the compare.
This patch removes the ordered entries and just uses the inverting logic that is now present. This removes some odd things in both the Mips and WebAssembly code.
Reviewers: efriedma, ABataev, uweigand, cameron.mcinally, kpn
Reviewed By: efriedma
Subscribers: dschuff, sdardis, sbc100, arichardson, jgravelle-google, kristof.beyls, hiraditya, aheejin, sunfish, atanasyan, Petar.Avramovic, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D72536
Summary:
In this patch, `ISD::RETURNADDR` is lowered on the emscripten target
to the new Emscripten runtime function `emscripten_return_address`, which
implements the functionality.
Patch by Guanzhong Chen
Reviewers: tlively, aheejin
Reviewed By: tlively
Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D62210
llvm-svn: 361454
r360889 added new llround builtin functions. This patch adds their
signatures for the WebAssembly backend.
It also adds wasm32 support to utils/update_llc_test_checks.py, since
that's the script other targets are using for their testcases for this
feature.
Differential Revision: https://reviews.llvm.org/D62207
llvm-svn: 361327
Add support for f16 libcalls in WebAssembly. This entails adding signatures
for the remaining F16 libcalls, and renaming gnu_f2h_ieee/gnu_h2f_ieee to
truncsfhf2/extendhfsf2 for consistency between f32 and f64/f128 (compiler-rt
already supports this).
Differential Revision: https://reviews.llvm.org/D61287
Reviewer: dschuff
llvm-svn: 359600
The WebAssembly backend needs to know the signatures of all runtime
libcall functions. This adds the signature for __stack_chk_fail which was
previously missing.
Also, make the error message for a missing libcall include the name of
the function.
Differential Revision: https://reviews.llvm.org/D59521
Reviewed By: sbc100
llvm-svn: 359505
Summary:
This patch fixes clang-tidy warnings on wasm-only files.
The list of checks used is:
`-*,clang-diagnostic-*,llvm-*,misc-*,-misc-unused-parameters,readability-identifier-naming,modernize-*`
(LLVM's default .clang-tidy list is the same except it does not have
`modernize-*`. But I've seen in multiple CLs in LLVM the modernize style
was recommended and code was fixed based on the style, so I added it as
well.)
The common fixes are:
- Variable names start with an uppercase letter
- Function names start with a lowercase letter
- Use `auto` when you use casts so the type is evident
- Use inline initialization for class member variables
- Use `= default` for empty constructors / destructors
- Use `using` in place of `typedef`
Reviewers: sbc100, tlively, aardappel
Subscribers: dschuff, sunfish, jgravelle-google, yurydelendik, kripken, MatzeB, mgorny, rupprecht, llvm-commits
Differential Revision: https://reviews.llvm.org/D57500
llvm-svn: 353075
to reflect the new license.
We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.
Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.
llvm-svn: 351636
When building with LTO, builtin functions that are defined but whose calls have not been inserted yet, get internalized. The Global Dead Code Elimination phase in the new LTO implementation then removes these function definitions. Later optimizations add calls to those functions, and the linker then dies complaining that there are no definitions. This CL fixes the new LTO implementation to check if a function is builtin, and if so, to not internalize (and later DCE) the function. As part of this fix I needed to move the RuntimeLibcalls.{def,h} files from the CodeGen subidrectory to the IR subdirectory. I have updated all the files that accessed those two files to access their new location.
Fixes PR34169
Patch by Caroline Tice!
Differential Revision: https://reviews.llvm.org/D49434
llvm-svn: 337847
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
Differential Revision: https://reviews.llvm.org/D46290
llvm-svn: 331272
This cast was causing invalid signatures to be written
for libcall functions.
Add an MC test which includes a call to builtin memcpy.
Differential Revision: https://reviews.llvm.org/D44037
llvm-svn: 326618
This will still be constexpr when the standard library supports it, but
doesn't force constexpr. Old libraries will get a global constructor,
which is not too bad.
llvm-svn: 326080
RuntimeLibcallSignatures previously manually initialized all the libcall
names into an array and searched it linearly for the first match to lookup
the corresponding index.
r322802 switched that to initializing a map keyed by the libcall name.
Neither of these approaches works correctly because some libcall numbers use
the same name on different platforms (e.g. the "l" suffixed functions
use f80 or f128 or ppcf128).
This change fixes that by ensuring that each name only goes into the map
once. It also adds tests.
Differential Revision: https://reviews.llvm.org/D42271
llvm-svn: 322971
Remove the tight coupling between llvm/CodeGenRuntimeLibcalls.def and
the table of supported singatures for wasm. This will allow adding new libcalls
without changing wasm's signature table.
Also, some cleanup:
Use ManagedStatics instead of const tables to avoid memory/binary bloat.
Use a StringMap instead of a linear search for name lookup.
Differential Revision: https://reviews.llvm.org/D35592
llvm-svn: 322802
Summary: Continuing the work from https://reviews.llvm.org/D33240, this change introduces an element unordered-atomic memset intrinsic. This intrinsic is essentially memset with the implementation requirement that all stores used for the assignment are done with unordered-atomic stores of a given element size.
Reviewers: eli.friedman, reames, mkazantsev, skatkov
Reviewed By: reames
Subscribers: jfb, dschuff, sbc100, jgravelle-google, aheejin, efriedma, llvm-commits
Differential Revision: https://reviews.llvm.org/D34885
llvm-svn: 307854
Summary:
Element atomic intrinsicAtomic instructions are not yet supported in WebAssembly, so we mark them as
unsupported for the moment.
Reviewers: sunfish, dschuff, sbc100
Reviewed By: dschuff, sbc100
Subscribers: jfb, sbc100, jgravelle-google
Differential Revision: https://reviews.llvm.org/D35322
llvm-svn: 307841
Summary:
Revision 307796 caused an internal build break in WebAssembly bots in the form of a
crash. ex:
Here's the crash dump from one of the failing tests:
/usr/local/google/home/blaikie/dev/llvm/build/default/./bin/llc < /usr/local/google/home/blaikie/dev/llvm/src/test/CodeGen/WebAssembly/global.ll -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals | /usr/local/google/home/blaikie/dev/llvm/build/default/./bin/FileCheck /usr/local/google/home/blaikie/dev/llvm/src/test/CodeGen/WebAssembly/global.ll
--
Exit Code: 2
Command Output (stderr):
--
Stack dump:
0. Program arguments: build/default/./bin/llc -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals
1. Running pass 'Function Pass Manager' on module '<stdin>'.
2. Running pass 'WebAssembly Assembly Printer' on function '@call_memcpy'
FileCheck error: '-' is empty.
FileCheck command line: build/default/./bin/FileCheck src/test/CodeGen/WebAssembly/global.ll
The problem is in lib/Target/WebAssembly/WebAssemblyRuntimeLibcallSignatures.cpp. There’s an array declared:
545 static const char *
Fix to web assembly lib call list
Summary:
Revision 307796 caused an internal build break in WebAssembly bots in the form of a
crash. ex:
Here's the crash dump from one of the failing tests:
/usr/local/google/home/blaikie/dev/llvm/build/default/./bin/llc < /usr/local/google/home/blaikie/dev/llvm/src/test/CodeGen/WebAssembly/global.ll -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals | /usr/local/google/home/blaikie/dev/llvm/build/default/./bin/FileCheck /usr/local/google/home/blaikie/dev/llvm/src/test/CodeGen/WebAssembly/global.ll
--
Exit Code: 2
Command Output (stderr):
--
Stack dump:
0. Program arguments: build/default/./bin/llc -asm-verbose=false -disable-wasm-fallthrough-return-opt -disable-wasm-explicit-locals
1. Running pass 'Function Pass Manager' on module '<stdin>'.
2. Running pass 'WebAssembly Assembly Printer' on function '@call_memcpy'
FileCheck error: '-' is empty.
FileCheck command line: build/default/./bin/FileCheck src/test/CodeGen/WebAssembly/global.ll
The problem is in lib/Target/WebAssembly/WebAssemblyRuntimeLibcallSignatures.cpp. There’s an array declared:
static const char *
RuntimeLibcallNames[RTLIB::UNKNOWN_LIBCALL] = {
That is defining a runtime lib call name for each entry in the enum RTLIB:Libcall from include/llvm/CodeGen/RuntimeLibcalls.h.
Revision 307796 added entries to the enum, but didn’t add entries to the RuntimeLibcallNames array, which caused a crash when attempting
to access past the end of the array.
This patch fixes the issue by adding the element atomic memmove to the WebAssembly arrays.
Reviewed by: reames
llvm-svn: 307831
Previously we were using the encoded LEB hex values
for the value types. This change uses the decoded
negative value and the LEB encoder to write them out.
Differential Revision: https://reviews.llvm.org/D30847
Patch by Sam Clegg
llvm-svn: 297777
LLVM CodeGen emits references to external symbols that are never declared in
LLVM IR level, so they have no declared signature. However, WebAssembly requires
all functions be declared with signatures. This patch adds a table for providing
signatures for known runtime libcalls that will be used in subsequent patches to
emit declarations for such functions.
llvm-svn: 295857
