Commit Graph

40 Commits

Author SHA1 Message Date
Wouter van Oortmerssen a617967d68 [WebAssembly] Assembler: support negative float constants.
Reviewers: dschuff

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64367

llvm-svn: 365802
2019-07-11 18:18:07 +00:00
Wouter van Oortmerssen 81db9f543c [WebAssembly] tablegen: distinguish float/int immediate operands.
Summary:
Before, they were one category of operands which could cause
crashes in non-sensical combinations, e.g. "f32.const symbol".
Now these are forced to be an error.

Reviewers: dschuff

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64039

llvm-svn: 365351
2019-07-08 16:58:37 +00:00
Wouter van Oortmerssen 319c87d94f [WebAssembly] Assembler: support .int16/32/64 directives.
Reviewers: sbc100

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63959

llvm-svn: 364689
2019-06-28 22:20:33 +00:00
Wouter van Oortmerssen fc222e23ca [WebAssembly] Assembler: Allow offsets and p2align in symbol load.
Reviewers: sbc100

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63951

llvm-svn: 364682
2019-06-28 20:31:13 +00:00
Wouter van Oortmerssen 597ba18008 [WebAssembly] Assembler: Improve section parsing.
Reviewers: sbc100

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63947

llvm-svn: 364681
2019-06-28 20:29:16 +00:00
Wouter van Oortmerssen bfd3f69480 [WebAssembly] AsmParser: better atomic inst detection
Summary:
Previously missed atomic.notify.

Fixes https://bugs.llvm.org/show_bug.cgi?id=40728

Reviewers: aheejin

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63747

llvm-svn: 364576
2019-06-27 18:58:26 +00:00
Wouter van Oortmerssen 6b3f56b65f [WebAssembly] Fix p2align in assembler.
Summary:
- Match the syntax output by InstPrinter.
- Fix it always emitting 0 for align. Had to work around fact that
  opcode is not available for GetDefaultP2Align while parsing.
- Updated tests that were erroneously happy with a p2align=0

Fixes https://bugs.llvm.org/show_bug.cgi?id=40752

Reviewers: aheejin, sbc100

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63633

llvm-svn: 364570
2019-06-27 18:11:15 +00:00
Heejin Ahn 65d8d6357b [WebAssembly] Remove catch_all from AsmParser
Summary:
`catch_all` is from the first version of EH proposal and now has been
removed. There were no tests covering this, and thus no tests to remove
or fix.

Reviewers: aardappel

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D63737

llvm-svn: 364360
2019-06-25 23:04:12 +00:00
Tom Stellard 4b0b26199b Revert CMake: Make most target symbols hidden by default
This reverts r362990 (git commit 374571301d)

This was causing linker warnings on Darwin:

ld: warning: direct access in function 'llvm::initializeEvexToVexInstPassPass(llvm::PassRegistry&)'
from file '../../lib/libLLVMX86CodeGen.a(X86EvexToVex.cpp.o)' to global weak symbol
'void std::__1::__call_once_proxy<std::__1::tuple<void* (&)(llvm::PassRegistry&),
std::__1::reference_wrapper<llvm::PassRegistry>&&> >(void*)' from file '../../lib/libLLVMCore.a(Verifier.cpp.o)'
means the weak symbol cannot be overridden at runtime. This was likely caused by different translation
units being compiled with different visibility settings.

llvm-svn: 363028
2019-06-11 03:21:13 +00:00
Tom Stellard 374571301d CMake: Make most target symbols hidden by default
Summary:
For builds with LLVM_BUILD_LLVM_DYLIB=ON and BUILD_SHARED_LIBS=OFF
this change makes all symbols in the target specific libraries hidden
by default.

A new macro called LLVM_EXTERNAL_VISIBILITY has been added to mark symbols in these
libraries public, which is mainly needed for the definitions of the
LLVMInitialize* functions.

This patch reduces the number of public symbols in libLLVM.so by about
25%.  This should improve load times for the dynamic library and also
make abi checker tools, like abidiff require less memory when analyzing
libLLVM.so

One side-effect of this change is that for builds with
LLVM_BUILD_LLVM_DYLIB=ON and LLVM_LINK_LLVM_DYLIB=ON some unittests that
access symbols that are no longer public will need to be statically linked.

Before and after public symbol counts (using gcc 8.2.1, ld.bfd 2.31.1):
nm before/libLLVM-9svn.so | grep ' [A-Zuvw] ' | wc -l
36221
nm after/libLLVM-9svn.so | grep ' [A-Zuvw] ' | wc -l
26278

Reviewers: chandlerc, beanz, mgorny, rnk, hans

Reviewed By: rnk, hans

Subscribers: Jim, hiraditya, michaelplatings, chapuni, jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, javed.absar, sbc100, jgravelle-google, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, zzheng, edward-jones, mgrang, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, kristina, jsji, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D54439

llvm-svn: 362990
2019-06-10 22:12:56 +00:00
Richard Trieu c6c421379d [WebAssembly] Create a TargetInfo header. NFC
Move the declarations of getThe<Name>Target() functions into a new header in
TargetInfo and make users of these functions include this new header.
This fixes a layering problem.

llvm-svn: 360735
2019-05-15 01:03:00 +00:00
Wouter van Oortmerssen f3feb6adb9 [WebAssembly] Add support for data sections in the assembler.
Summary:
This is quite minimal so far, introduce them with .section,
fill them with .int8 or .asciz, end with .size

Reviewers: dschuff, sbc100, aheejin

Subscribers: jgravelle-google, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58660

llvm-svn: 355321
2019-03-04 17:18:04 +00:00
Heejin Ahn 3477bd12a0 [WebAssembly] Fix load/store name detection for atomic instructions
Summary:
Fixed a bug in the routine in AsmParser that determines whether the
current instruction is a load or a store. Atomic instructions' prefixes
are not `atomic_` but `atomic.`, and all atomic instructions are also
memory instructions. Also fixed the printing format of atomic
instructions to match other memory instructions and added encoding tests
for atomic instructions.

Reviewers: aardappel, tlively

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

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58337

llvm-svn: 354419
2019-02-20 01:14:36 +00:00
Heejin Ahn 18c56a0762 [WebAssembly] clang-tidy (NFC)
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
2019-02-04 19:13:39 +00:00
Wouter van Oortmerssen 0b3cf247c4 [WebAssembly] Make segment/size/type directives optional in asm
Summary:
These were "boilerplate" that repeated information already present
in .functype and end_function, that needed to be repeated to Please
the particular way our object writing works, and missing them would
generate errors.

Instead, we generate the information for these automatically so the
user can concern itself with writing more canonical wasm functions
that always work as expected.

Reviewers: dschuff, sbc100

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

Differential Revision: https://reviews.llvm.org/D57546

llvm-svn: 353067
2019-02-04 18:03:11 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

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

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

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Wouter van Oortmerssen f3b762a0b6 [WebAssembly] Fixed objdump not parsing function headers.
Summary:
objdump was interpreting the function header containing the locals
declaration as instructions. To parse these without injecting target
specific code in objdump, MCDisassembler::onSymbolStart was added to
be implemented by the WebAssembly implemention.

WasmObjectFile now returns a code offset for the "address" of a symbol,
rather than the index. This is also more in-line with what other
targets do.

Also ensured that the AsmParser correctly puts each function
in its own segment to enable this test case.

Reviewers: sbc100, dschuff

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

Differential Revision: https://reviews.llvm.org/D56684

llvm-svn: 351460
2019-01-17 18:14:09 +00:00
Wouter van Oortmerssen ad72f68501 [WebAssembly] made assembler parse block_type
Summary:
This was previously ignored and an incorrect value generated.

Also fixed Disassembler's handling of block_type.

Reviewers: dschuff, aheejin

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

Differential Revision: https://reviews.llvm.org/D56092

llvm-svn: 350270
2019-01-02 23:23:51 +00:00
Wouter van Oortmerssen f227621036 [WebAssembly] Added basic support for if/else/end_if in MC layer.
Summary:
These instructions are currently unused in our backend, but for
completeness it is good to support them, so they can be used with
the assembler in hand-written code.

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

Reviewers: dschuff, aheejin

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

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

llvm-svn: 350079
2018-12-26 22:55:26 +00:00
Wouter van Oortmerssen 29c6ce5879 [WebAssembly] Make assembler check for proper nesting of control flow.
Summary:
It does so using a simple nesting stack, and gives clear errors upon
violation. This is unique to wasm, since most CPUs do not have
any nested constructs.

Had to add an end of file check to the general assembler for this.

Note: if/else/end instructions are not currently supported in our
tablegen defs, so these tests will be enabled in a follow-up.
They already pass the nesting check.

Reviewers: dschuff, aheejin

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

Differential Revision: https://reviews.llvm.org/D55797

llvm-svn: 350078
2018-12-26 22:46:18 +00:00
Wouter van Oortmerssen d3c544aa6e [WebAssembly] Fix assembler parsing of br_table.
Summary:
We use `variable_ops` in the tablegen defs to denote the list of
branch targets in `br_table`, but unlike other uses of `variable_ops`
(e.g. call) the these branch targets need to actually be encoded in the
instruction. The existing tables for `variable_ops` cause not operands
to be accepted by the assembly matcher.

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

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

Reviewers: dschuff, aheejin, sunfish

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

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

llvm-svn: 349405
2018-12-17 22:04:44 +00:00
Heejin Ahn be5e5874f6 [WebAssembly] Add '.eventtype' directive support
Summary:
This patch supports `.eventtype` directive printing and parsing in the
same syntax with `.functype`.

Reviewers: aardappel, sbc100

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

Differential Revision: https://reviews.llvm.org/D55353

llvm-svn: 348818
2018-12-11 01:11:04 +00:00
Heejin Ahn 7ce5edf1ea [WebAssembly] clang-format/clang-tidy AsmParser (NFC)
Summary:
- LLVM clang-format style doesn't allow one-line ifs.
- LLVM clang-tidy style says method names should start with a lowercase
  letter. But currently WebAssemblyAsmParser's parent class
  MCTargetAsmParser is mixing lowercase and uppercase method names
  itself so overridden methods cannot be renamed now.
- Changed else ifs after returns to ifs.
- Added some newlines for readability.

Reviewers: aardappel, sbc100

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

Differential Revision: https://reviews.llvm.org/D55350

llvm-svn: 348648
2018-12-07 21:35:37 +00:00
Wouter van Oortmerssen c7b89f0f62 [WebAssembly] Enforce assembler emits to streamer in order.
Summary:
The assembler processes directives and instructions in whatever order
they are in the file, then directly emits them to the streamer. This
could cause badly written (or generated) .s files to produce
incorrect binaries.

It now has state that tracks what it has most recently seen, to
enforce they are emitted in a given order that always produces
correct wasm binaries.

Also added a new test that compares obj2yaml output from llc (the
backend) to that going via .s and the assembler to ensure both paths
generate the same binaries.

The features this test covers could be extended.

Passes all wasm Lit tests.

Fixes: https://bugs.llvm.org/show_bug.cgi?id=39557

Reviewers: sbc100, dschuff, aheejin

Subscribers: jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D55149

llvm-svn: 348185
2018-12-03 20:30:28 +00:00
Wouter van Oortmerssen 49482f824a [WebAssembly] replaced .param/.result by .functype
Summary:
This makes it easier/cleaner to generate a single signature from
this directive. Also:
- Adds the symbol name, such that we don't depend on the location
  of this directive anymore.
- Actually constructs the signature in the assembler, and make the
  assembler own it.
- Refactor the use of MVT vs ValType in the streamer and assembler
  to require less conversions overall.
- Changed 700 or so tests to use it.

Reviewers: sbc100, dschuff

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

Differential Revision: https://reviews.llvm.org/D54652

llvm-svn: 347228
2018-11-19 17:10:36 +00:00
Wouter van Oortmerssen cc75e77df5 [WebAssembly] Added WasmAsmParser.
Summary:
This is to replace the ELFAsmParser that WebAssembly was using, which
so far was a stub that didn't do anything, and couldn't work correctly
with wasm.

This new class is there to implement generic directives related to
wasm as a binary format. Wasm target specific directives are still
parsed in WebAssemblyAsmParser as before. The two classes now
cooperate more correctly too.

Also implemented .result which was missing. Any unknown directives
will now result in errors.

Reviewers: dschuff, sbc100

Subscribers: mgorny, jgravelle-google, eraman, aheejin, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D54360

llvm-svn: 346700
2018-11-12 20:15:01 +00:00
Wouter van Oortmerssen de28b5d17f [WebAssembly] Parsing missing directives to produce valid .o
Summary:
The assembler was able to assemble and then dump back to .s, but
was failing to parse certain directives necessary for valid .o
output:
- .type directives are now recognized to distinguish function symbols
  and others.
- .size is now parsed to provide function size.
- .globaltype (introduced in https://reviews.llvm.org/D54012) is now
  recognized to ensure symbols like __stack_pointer have a proper type
  set for both .s and .o output.

Also added tests for the above.

Reviewers: sbc100, dschuff

Subscribers: jgravelle-google, aheejin, dexonsmith, kristina, llvm-commits, sunfish

Differential Revision: https://reviews.llvm.org/D53842

llvm-svn: 346047
2018-11-02 22:04:33 +00:00
Heejin Ahn 2e398976ba [WebAssembly] Fix signature parsing for 'try' in AsmParser
Summary:
Like `block` or `loop`, `try` can take an optional signature which can
be omitted. This patch allows `try`'s signature to be omitted. Also
added some tests for EH instructions.

Reviewers: aardappel

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

Differential Revision: https://reviews.llvm.org/D53873

llvm-svn: 345888
2018-11-01 20:32:15 +00:00
Wouter van Oortmerssen 0c83c3ff38 [WebAssembly] Fixed AsmParser not allowing instructions with /
Summary:
The AsmParser Lexer regards these as a seperate token.
Here we expand the instruction name with them if they are
adjacent (no whitespace).

Tested: the basic-assembly.s test case has one case with a / in it.
The currently are also instructions with : in them, which we intend
to rename rather than fix them here.

Reviewers: tlively, dschuff

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

Differential Revision: https://reviews.llvm.org/D52442

llvm-svn: 343501
2018-10-01 17:20:31 +00:00
Heejin Ahn f208f6311b [WebAssembly] clang-format (NFC)
Summary: This patch runs clang-format on all wasm-only files.

Reviewers: aardappel, dschuff, sunfish, tlively

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

Differential Revision: https://reviews.llvm.org/D51447

llvm-svn: 341439
2018-09-05 01:27:38 +00:00
Wouter van Oortmerssen 8a9cb242fb [WebAssembly] Added default stack-only instruction mode for MC.
Summary:
Made it convert from register to stack based instructions, and removed the registers.
Fixes to related code that was expecting register based instructions.
Added the correct testing flag to all tests, depending on what the
format they were expecting so far.
Translated one test to stack format as example: reg-stackify-stack.ll

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

Reviewers: dschuff, sunfish

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

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

llvm-svn: 340750
2018-08-27 15:45:51 +00:00
Thomas Lively 22442924a8 [WebAssembly] v128.const
Summary:
This CL implements v128.const for each vector type. New operand types
are added to ensure the vector contents can be serialized without LEB
encoding. Tests are added for instruction selection, encoding,
assembly and disassembly.

Reviewers: aheejin, dschuff, aardappel

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

Differential Revision: https://reviews.llvm.org/D50873

llvm-svn: 340336
2018-08-21 21:03:18 +00:00
Wouter van Oortmerssen a7be375586 Revert "[WebAssembly] Added default stack-only instruction mode for MC."
This reverts commit 917a99b71ce21c975be7bfbf66f4040f965d9f3c.

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

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

Reviewers: dschuff, sunfish

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

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

llvm-svn: 339474
2018-08-10 21:32:47 +00:00
Wouter van Oortmerssen a90d24da1c Revert "[WebAssembly] Added default stack-only instruction mode for MC."
This reverts commit d3c9af4179eae7793d1487d652e2d4e23844555f.
(SVN revision 338164)

llvm-svn: 338176
2018-07-27 23:19:51 +00:00
Wouter van Oortmerssen a67c4137c3 [WebAssembly] Added default stack-only instruction mode for MC.
Summary:
Moved Explicit Locals pass to last.
Made that pass obligatory.
Made it convert from register to stack based instructions, and removed the registers.
Fixes to related code that was expecting register based instructions.
Added the correct testing flag to all tests, depending on what the
format they were expecting so far.
Translated one test to stack format as example: reg-stackify-stack.ll

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

Reviewers: dschuff, sunfish

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

Differential Revision: https://reviews.llvm.org/D49160

llvm-svn: 338164
2018-07-27 20:56:43 +00:00
Adrian Prantl 5f8f34e459 Remove \brief commands from doxygen comments.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.

Patch produced by

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

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

llvm-svn: 331272
2018-05-01 15:54:18 +00:00
Reid Kleckner 440219d53e [WebAssembly] Really disable wasm register name matcher
The "ShouldEmitMatchRegisterName" bit wasn't taking effect because the
WebAssembly target didn't point to the custom WebAssemblyAsmParser
record.

llvm-svn: 328155
2018-03-21 21:46:47 +00:00
Reid Kleckner 18574836f9 [WebAssembly] Suppress unused function warning for register name matcher
llvm-svn: 328112
2018-03-21 16:20:58 +00:00
Derek Schuff e4825975d8 [WebAssembly] Added initial AsmParser implementation.
It uses the MC framework and the tablegen matcher to do the
heavy lifting. Can handle both explicit and implicit locals
(-disable-wasm-explicit-locals). Comes with a small regression
test.

This is a first basic implementation that can parse most llvm .s
output and round-trips most instructions succesfully, but in order
to keep the commit small, does not address all issues.

There are a fair number of mismatches between what MC / assembly
matcher think a "CPU" should look like and what WASM provides,
some already have workarounds in this commit (e.g. the way it
deals with register operands) and some that require further work.
Some of that further work may involve changing what the
Disassembler outputs (and what s2wasm parses), so are probably
best left to followups.

Some known things missing:
- Many directives are ignored and not emitted.
- Vararg calls are parsed but extra args not emitted.
- Loop signatures are likely incorrect.
- $drop= is not emitted.
- Disassembler does not output SIMD types correctly, so assembler
  can't test them.

Patch by Wouter van Oortmerssen

Differential Revision: https://reviews.llvm.org/D44329

llvm-svn: 328028
2018-03-20 20:06:35 +00:00