Commit Graph

57 Commits

Author SHA1 Message Date
Rafael Espindola
64d3ae0c39 Move EmitDwarfAdvanceLineAddr and EmitDwarfAdvanceFrameAddr to the obj streamer.
This lets us delete the MCAsmStreamer implementation. No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208570 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-12 14:43:25 +00:00
Rafael Espindola
23f2d7ae23 Move EH/Debug frame handling to the object streamer.
Now that the asm streamer doesn't use it, the MCStreamer doesn't need to know
about it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208562 91177308-0d34-0410-b5e6-96231b3b80d8
2014-05-12 14:02:44 +00:00
Rafael Espindola
14a1490eb8 Make getOrCreateSymbolData non virtual.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207367 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-27 17:23:37 +00:00
Kevin Enderby
29c96f133e Fix the assembler to print a better relocatable expression error
diagnostic that includes location information.

Currently if one has this assembly:

	.quad (0x1234 + (4 * SOME_VALUE))

where SOME_VALUE is undefined ones gets the less than
useful error message with no location information:

% clang -c x.s
clang -cc1as: fatal error: error in backend: expected relocatable expression

With this fix one now gets a more useful error message
with location information:

% clang -c x.s 
x.s:5:8: error: expected relocatable expression
 .quad (0x1234 + (4 * SOME_VALUE))
       ^

To do this I plumbed the SMLoc through the MCObjectStreamer
EmitValue() and EmitValueImpl() interfaces so it could be used
when creating the MCFixup.

rdar://12391022


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206906 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-22 17:27:29 +00:00
Craig Topper
5747a143a2 [C++11] Add 'override' keyword to virtual methods that override their base class.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203340 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-08 07:02:02 +00:00
Daniel Sanders
38c6b58eec Re-commit: Demote EmitRawText call in AsmPrinter::EmitInlineAsm() and remove hasRawTextSupport() call
Summary:
AsmPrinter::EmitInlineAsm() will no longer use the EmitRawText() call for
targets with mature MC support. Such targets will always parse the inline
assembly (even when emitting assembly). Targets without mature MC support
continue to use EmitRawText() for assembly output.

The hasRawTextSupport() check in AsmPrinter::EmitInlineAsm() has been replaced
with MCAsmInfo::UseIntegratedAs which when true, causes the integrated assembler
to parse inline assembly (even when emitting assembly output). UseIntegratedAs
is set to true for targets that consider any failure to parse valid assembly
to be a bug. Target specific subclasses generally enable the integrated
assembler in their constructor. The default value can be overridden with
-no-integrated-as.

All tests that rely on inline assembly supporting invalid assembly (for example,
those that use mnemonics such as 'foo' or 'hello world') have been updated to
disable the integrated assembler.

Changes since review (and last commit attempt):
- Fixed test failures that were missed due to configuration of local build.
  (fixes crash.ll and a couple others).
- Fixed tests that happened to pass because the local build was on X86
  (should fix 2007-12-17-InvokeAsm.ll)
- mature-mc-support.ll's should no longer require all targets to be compiled.
  (should fix ARM and PPC buildbots)
- Object output (-filetype=obj and similar) now forces the integrated assembler
  to be enabled regardless of default setting or -no-integrated-as.
  (should fix SystemZ buildbots)

Reviewers: rafael

Reviewed By: rafael

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D2686



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@201333 91177308-0d34-0410-b5e6-96231b3b80d8
2014-02-13 14:44:26 +00:00
David Woodhouse
d5d381b762 Modify MCObjectStreamer EmitInstTo* interface
Add MCSubtargetInfo parameter
virtual void EmitInstToFragment(const MCInst &Inst, const MCSubtargetInfo &);
virtual void EmitInstToData(const MCInst &Inst, const MCSubtargetInfo &);

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200346 91177308-0d34-0410-b5e6-96231b3b80d8
2014-01-28 23:12:49 +00:00
David Woodhouse
4396f5d9d2 Change MCStreamer EmitInstruction interface to take subtarget info
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200345 91177308-0d34-0410-b5e6-96231b3b80d8
2014-01-28 23:12:42 +00:00
Rafael Espindola
aa75693ea4 Construct the MCStreamer before constructing the MCTargetStreamer.
This has a few advantages:
* Only targets that use a MCTargetStreamer have to worry about it.
* There is never a MCTargetStreamer without a MCStreamer, so we can use a
  reference.
* A MCTargetStreamer can talk to the MCStreamer in its constructor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200129 91177308-0d34-0410-b5e6-96231b3b80d8
2014-01-26 06:06:37 +00:00
Rafael Espindola
320296a4cf Add a MCTargetStreamer interface.
This patch fixes an old FIXME by creating a MCTargetStreamer interface
and moving the target specific functions for ARM, Mips and PPC to it.

The ARM streamer is still declared in a common place because it is
used from lib/CodeGen/ARMException.cpp, but the Mips and PPC are
completely hidden in the corresponding Target directories.

I will send an email to llvmdev with instructions on how to use this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192181 91177308-0d34-0410-b5e6-96231b3b80d8
2013-10-08 13:08:17 +00:00
Rafael Espindola
5e195a4c8d Remove some really nasty uses of hasRawTextSupport.
When MC was first added, targets could use hasRawTextSupport to keep features
working before they were added to the MC interface.

The design goal of MC is to provide an uniform api for printing assembly and
object files. Short of relaxations and other corner cases, a object file is
just another representation of the assembly.

It was never the intention that targets would keep doing things like

if (hasRawTextSupport())
  Set flags in one way.
else
  Set flags in another way.

When they do that they create two code paths and the object file is no longer
just another representation of the assembly. This also then requires testing
with llc -filetype=obj, which is extremelly brittle.

This patch removes some of these hacks by replacing them with smaller ones.
The ARM flag setting is trivial, so I just moved it to the constructor. For
Mips, the patch adds two temporary hack directives that allow the assembly
to represent the same things as the object file was already able to.

The hope is that the mips developers will replace the hack directives with
the same ones that gas uses and drop the -print-hack-directives flag.

I will also try to implement a target streamer interface, so that we can
move this out of the common code.

In summary, for any new work, two rules of the thumb are
  * Don't use "llc -filetype=obj" in tests.
  * Don't add calls to hasRawTextSupport.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192035 91177308-0d34-0410-b5e6-96231b3b80d8
2013-10-05 16:42:21 +00:00
Rafael Espindola
a3863ea2da Remove address spaces from MC.
This is dead code since PIC16 was removed in 2010. The result was an odd mix,
where some parts would carefully pass it along and others would assert it was
zero (most of the object streamer for example).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185436 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-02 15:49:13 +00:00
Serge Pavlov
b02f1e9a6b Use MCFillFragment for zero-initialized data.
It fixes PR16338 (ICE when compiling very large two-dimensional array).

Differential Revision: http://llvm-reviews.chandlerc.com/D1043


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185080 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-27 14:35:03 +00:00
Ulrich Weigand
4df4bccc71 [MC/DWARF] Generate multiple .debug_line entries for adjacent .loc directives
The compiler occasionally generates multiple .loc directives in a row
(at the same instruction address).  These need to be transformed into
multple actual .debug_line table entries, since they are used to signal
certain information to the debugger (e.g. if the opening brace of a
function body is on the same line as the declaration).

The MCAsmStreamer version of EmitDwarfLocDirective handles this
correctly by emitting a .loc directive every time it is called.
However, the MCObjectStream version simply defaults to recording
the information and emitting only a single table entry later,
e.g. when EmitInstruction is called.

This patch introduces a MCAsmStreamer::EmitDwarfLocDirective
version that emits a line table entry for a .loc directive
that may already be pending before recording the new directive.
(This is similar to how this is handled in GNU as.)

With this patch (and the code alignment factor patch) applied,
I'm now getting identical DWARF .debug sections for all test-suite
object files on PowerPC for the internal and the external assembler.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@184357 91177308-0d34-0410-b5e6-96231b3b80d8
2013-06-19 21:27:27 +00:00
Peter Collingbourne
df39be6cb4 Add support for subsections to the ELF assembler. Fixes PR8717.
Differential Revision: http://llvm-reviews.chandlerc.com/D598

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179725 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-17 21:18:16 +00:00
Chandler Carruth
5da3665cc5 Give the MCStreamer class hierarchy LLVM RTTI facilities for use with
isa<> and dyn_cast<>. In several places, code is already hacking around
the absence of this, and there seem to be several interfaces that might
be lifted and/or devirtualized using this.

This change was based on a discussion with Jim Grosbach about how best
to handle testing for specific MCStreamer subclasses. He said that this
was the correct end state, and everything else was too hacky so
I decided to just make it so.

No functionality should be changed here, this is just threading the kind
through all the constructors and setting up the classof overloads.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@174113 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-31 23:29:57 +00:00
Eric Christopher
ca1dd05c3c These functions have default arguments of 0 for the last arg. Use
them and add one where it seemed obvious that we wanted one.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171932 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-09 01:35:34 +00:00
Eli Bendersky
6c1d4972cf Add the align_to_end option to .bundle_lock in the MC implementation of aligned
bundling. The document describing this feature and the implementation has also
been updated:

https://sites.google.com/a/chromium.org/dev/nativeclient/pnacl/aligned-bundling-support-in-llvm


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171797 91177308-0d34-0410-b5e6-96231b3b80d8
2013-01-07 21:51:08 +00:00
Eli Bendersky
4766ef41b3 Aligned bundling support. Following the discussion here:
http://lists.cs.uiuc.edu/pipermail/llvmdev/2012-December/056754.html

The proposal and implementation are fully documented here:
https://sites.google.com/a/chromium.org/dev/nativeclient/pnacl/aligned-bundling-support-in-llvm

Tests will follow shortly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170718 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-20 19:05:53 +00:00
Reed Kotler
2c3a4641a7 This patch is needed to make c++ exceptions work for mips16.
Mips16 is really a processor decoding mode (ala thumb 1) and in the same
program, mips16 and mips32 functions can exist and can call each other.

If a jal type instruction encounters an address with the lower bit set, then
the processor switches to mips16 mode (if it is not already in it). If the
lower bit is not set, then it switches to mips32 mode.

The linker knows which functions are mips16 and which are mips32.
When relocation is performed on code labels, this lower order bit is
set if the code label is a mips16 code label.

In general this works just fine, however when creating exception handling
tables and dwarf, there are cases where you don't want this lower order
bit added in.

This has been traditionally distinguished in gas assembly source by using a
different syntax for the label.

lab1:      ; this will cause the lower order bit to be added
lab2=.     ; this will not cause the lower order bit to be added

In some cases, it does not matter because in dwarf and debug tables
the difference of two labels is used and in that case the lower order
bits subtract each other out.

To fix this, I have added to mcstreamer the notion of a debuglabel.
The default is for label and debug label to be the same. So calling
EmitLabel and EmitDebugLabel produce the same result.

For various reasons, there is only one set of labels that needs to be
modified for the mips exceptions to work. These are the "$eh_func_beginXXX" 
labels.

Mips overrides the debug label suffix from ":" to "=." .

This initial patch fixes exceptions. More changes most likely
will be needed to DwarfCFException to make all of this work
for actual debugging. These changes will be to emit debug labels in some
places where a simple label is emitted now.

Some historical discussion on this from gcc can be found at:
http://gcc.gnu.org/ml/gcc-patches/2008-08/msg00623.html
http://gcc.gnu.org/ml/gcc-patches/2008-11/msg01273.html 



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170279 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-16 04:00:45 +00:00
Pedro Artigas
5399d2502a Make the MCStreamer have a reset method and call that after finalization of the asm printer,
also changed MCContext to a single reset only method for simplicity as requested on the list



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@170041 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-12 22:59:46 +00:00
Eli Bendersky
ef76b273f9 Lift EmitAssignment into MCObjectStreamer which gets rid of at least three
duplicate implementations in format-specific streamers.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169613 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-07 17:42:41 +00:00
Benjamin Kramer
e660fc15fe Hoist some grossly duplicated code from the COFF/ELF/MachO streamers into MCObjectStreamer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165225 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-04 13:12:43 +00:00
Benjamin Kramer
f0070f2a97 Provide a shortcut for MCObjectStreamer when emitting fills.
Reduces runtime of i386-large-relocations.s by 10x in Release builds, even more
in Debug+Asserts builds.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164945 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-01 15:14:14 +00:00
Jack Carter
101771ba4d For mips64 switch statements in subroutines could generate
within the codegen EK_GPRel64BlockAddress. This was not 
supported for direct object output and resulted in an assertion.

This change adds support for EK_GPRel64BlockAddress for 
direct object.

One fallout from this is to turn on rela relocations 
for mips64 to match gas.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162334 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-22 00:49:30 +00:00
Jim Grosbach
ebd4c05c3c Better diagnostic for malformed .org assembly directive.
Provide source line number information.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149101 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-27 00:37:08 +00:00
Rafael Espindola
1fe9737eb4 Don't print an unused label before .cfi_endproc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147763 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-09 00:17:29 +00:00
Rafael Espindola
547be2699c Don't print a label before .cfi_startproc when we don't need to. This makes
the produce assembly when using CFI just a bit more readable.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147743 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-07 22:42:19 +00:00
Rafael Espindola
99b4237c16 Split Finish into Finish and FinishImpl to have a common place to do end of
file error checking. Use that to error on an unfinished cfi_startproc.

The error is not nice, but is already better than a segmentation fault.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147717 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-07 03:13:18 +00:00
Akira Hatanaka
84bfc2f090 This patch addresses gp relative fixups/relocations for jump tables.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145112 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-23 22:18:04 +00:00
Evan Cheng
78c10eeaa5 Rename TargetAsmBackend to MCAsmBackend; rename createAsmBackend to createMCAsmBackend.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136010 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-25 23:24:55 +00:00
Evan Cheng
672b93a332 Unfortunately several files in MC are badly violating layering rule by using
TargetAsmInfo, which in turn pulls in TargetRegisterInfo, etc. :-( There are
other cases of violations, but this is probably the worst.

This patch is but one small step towards fixing this. 500 more steps to go. :-(


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135131 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-14 05:43:07 +00:00
Rafael Espindola
debd7e4e8b Simplify the handling of pcrel relocations on ELF. Now we do the right thing
for all symbol differences and can drop the old EmitPCRelSymbolValue
method.

This also make getExprForFDESymbol on ELF equal to the one on MachO, and it
can be made non-virtual.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130634 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-01 03:50:49 +00:00
Rafael Espindola
e8cfbd843d Remove unused argument.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129955 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-21 23:39:26 +00:00
Jan Sjödin
01dff96461 Add constructors to MCElfStreamer and MCObjectStreamer to take an extra MCAssembler * argument.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127343 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-09 17:33:05 +00:00
Rafael Espindola
7768a9dce1 Add support for pushsection and popsection. Patch by Joerg Sonnenberger.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125629 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-16 01:08:29 +00:00
Rafael Espindola
245a1e2041 Relax address updates in the eh_frame section.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122591 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-28 05:39:27 +00:00
Rafael Espindola
89b9372605 Fixed version of 121434 with no new memory leaks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121471 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-10 07:39:47 +00:00
Rafael Espindola
f7fd4aa261 Revert my previous patch to make the valgrind bots happy.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121461 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-10 04:01:09 +00:00
Rafael Espindola
1c952b9cc9 Initial support for the cfi directives. This is just enough to get
f:
        .cfi_startproc
        nop
        .cfi_endproc

assembled (on ELF).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121434 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-09 23:48:29 +00:00
Rafael Espindola
85f2ecc697 Sorry for such a large commit. The summary is that only MachO cares about the
actuall addresses in a .o file, so it is better to let the MachO writer compute
it.

This is good for two reasons. First, areas that shouldn't care about
addresses now don't have access to it. Second, the layout of each section
is independent. I should use this in a subsequent commit to speed it up.

Most of the patch is just removing the section address computation. The two
interesting parts are the change on how we handle padding in the end
of sections and how MachO can get the address of a-b when a and b are in
different sections.

Since now the expression evaluation normally doesn't know the section address,
it will think that a-b needs relocation and let the MachO writer know. Once
it has computed the section addresses, it calls back the expression evaluation
with the section addresses to resolve these expressions.

The remaining problem is the handling of padding. Currently it will create
a special alignment fragment at the end. Since that fragment doesn't update
the alignment of the section, it needs the real address to be computed.

Since now the layout will not compute a-b with a and b in different sections,
the only effect that the special alignment fragment has is update the
address size of the section. This can also be done by the MachO writer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121076 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-07 00:27:36 +00:00
Rafael Espindola
5d4918dbd1 There are two reasons why we might want to use
foo = a - b
.long foo
instead of just
.long a - b

First, on darwin9 64 bits the assembler produces the wrong result. Second,
if "a" is the end of the section all darwin assemblers (9, 10 and mc) will not
consider a - b to be a constant but will if the dummy foo is created.

Split how we handle these cases. The first one is something MC should take care
of. The second one has to be handled by the caller.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120889 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-04 03:21:47 +00:00
Rafael Espindola
32a006e606 Try to resolve symbol differences early, and if successful create a plain
data fragment. This reduces the time to assemble the test in 8711 from 60s to
54s.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120767 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-03 00:55:40 +00:00
Devang Patel
ee4854faf3 Use set directive for StartMinusEndExpr.
This is a fix for llvm-gcc-i386-darwin9 buildbot failure.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120742 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-02 21:32:30 +00:00
Rafael Espindola
e23930543c Move EmitValueToOffset to the ObjectStreamer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120691 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-02 05:59:38 +00:00
Rafael Espindola
dedb045c32 Add EmitInstToFragment to the generic object streamer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120690 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-02 05:44:06 +00:00
Rafael Espindola
6f95023a7f Move EmitValue to MCObjectStreamer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120269 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-28 23:08:47 +00:00
Rafael Espindola
ea4afa91eb Fixed verson of r120245.
Factor some duplicated code into MCObjectStreamer::EmitLabel.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120248 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-28 17:18:55 +00:00
Rafael Espindola
ba210243ef Revert previous patch while I debug the darwin bootstrap failure.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120246 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-28 16:22:59 +00:00
Rafael Espindola
f90a2de72c Factor some duplicated code into MCObjectStreamer::EmitLabel.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120245 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-28 15:54:36 +00:00