Commit Graph

413 Commits

Author SHA1 Message Date
Ian Lance Taylor 9195aa172b libgo: fix build on AIX
Since aix/ppc64 has been added to GC toolchain, a mix between new and
    old files were created in gcc toolchain.
    This commit corrects this merge for aix/ppc64 and aix/ppc.
    
    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/167658

From-SVN: r269797
2019-03-19 14:00:59 +00:00
Ian Lance Taylor 6bd37418a3 runtime: abort stack scan in cases that we cannot unwind the stack
In signal-triggered stack scan, if the signal is delivered at
    certain bad time (e.g. in vdso, or in the middle of setcontext?),
    the unwinder may not be able to unwind the whole stack, while it
    still reports _URC_END_OF_STACK. So we cannot rely on _URC_END_OF_STACK
    to tell if it successfully scanned the stack. Instead, we check
    the last Go frame to see it actually reached the end of the stack.
    For Go-created stack, this is runtime.kickoff. For C-created
    stack, we need to record the outermost Go frame when it enters
    the Go side.
    
    Also we cannot unwind the stack if the signal is delivered in the
    middle of runtime.gogo, halfway through a goroutine switch, where
    the g and the stack don't match. Give up in this case as well.
    
    Reviewed-on: https://go-review.googlesource.com/c/159098

From-SVN: r269018
2019-02-19 15:32:34 +00:00
Cherry Zhang fba70f605e compiler,runtime: use __builtin_dwarf_cfa for getcallersp
Currently, the compiler lowers runtime.getcallersp to
    __builtin_frame_address(1). In the C side of the runtime,
    getcallersp is defined as __builtin_frame_address(0). They don't
    match. Further, neither of them actually returns the caller's SP.
    On AMD64, __builtin_frame_address(0) just returns the frame
    pointer. __builtin_frame_address(1) returns the memory content
    where the frame pointer points to, which is typically the
    caller's frame pointer but can also be garbage if the frame
    pointer is not enabled.
    
    This CL changes it to use __builtin_dwarf_cfa(), which returns
    the caller's SP at the call site. This matches the SP we get
    from unwinding the stack.
    
    Currently getcallersp is not used for anything real. It will be
    used for precise stack scan (a new version of CL 159098).
    
    Reviewed-on: https://go-review.googlesource.com/c/162905

	* go-gcc.cc (Gcc_backend::Gcc_backend): Define __builtin_dwarf_cfa
	instead of __builtin_frame_address.

From-SVN: r268952
2019-02-15 23:22:29 +00:00
Ian Lance Taylor 7b54753033 runtime: include <syscall.h> and <sys/syscall.h> if available
Fixes Solaris build.
    
    Reviewed-on: https://go-review.googlesource.com/c/162885

From-SVN: r268940
2019-02-15 14:25:12 +00:00
Ian Lance Taylor d86dd2490f runtime: add type cast for non-split-stack calls to scanstackblock
Reviewed-on: https://go-review.googlesource.com/c/162884

From-SVN: r268939
2019-02-15 13:54:45 +00:00
Ian Lance Taylor 8a9f2a6bbd compiler, runtime: harmonize types referenced by both C and Go
Compiling with LTO revealed a number of cases in the runtime and
    standard library where C and Go disagreed about the type of an object or
    function (or where Go and code generated by the compiler disagreed). In
    all cases the underlying representation was the same (e.g., uintptr vs.
    void*), so this wasn't causing actual problems, but it did result in a
    number of annoying warnings when compiling with LTO.
    
    Reviewed-on: https://go-review.googlesource.com/c/160700

From-SVN: r268923
2019-02-15 01:57:51 +00:00
Ian Lance Taylor cf5773c116 runtime: add getproccount for hurd
Patch by Svante Signell.
    
    Reviewed-on: https://go-review.googlesource.com/c/160825

From-SVN: r268463
2019-02-01 22:55:55 +00:00
Ian Lance Taylor 27d6b51071 libgo: add hurd build tags
Patch by Svante Signell.
    
    Reviewed-on: https://go-review.googlesource.com/c/160822

From-SVN: r268459
2019-02-01 21:57:36 +00:00
Ian Lance Taylor b52a3881f0 runtime, sync: use __atomic intrinsics instead of __sync
GCC has supported the __atomic intrinsics since 4.7.  They are better
    than the __sync intrinsics in that they specify a memory model and,
    more importantly for our purposes, they are reliably implemented
    either in the compiler or in libatomic.
    
    Fixes https://gcc.gnu.org/PR52084
    
    Reviewed-on: https://go-review.googlesource.com/c/160820

From-SVN: r268458
2019-02-01 21:55:38 +00:00
Ian Lance Taylor 053a1f2320 runtime: use the call instruction's PC for panic-in-runtime detection
If a panic happens in the runtime we turn that into a fatal error.
    We use the caller's PC to determine if the panic call is inside
    the runtime. getcallerpc returns the PC immediately after the
    call instruction. If the call is the very last instruction of a
    function, it may not find this PC belong to a runtime function,
    giving false result. We need to back off the PC by 1 to the call
    instruction.
    
    The gc runtime doesn't do this because the gc compiler always
    emit an instruction following a panic call, presumably an UNDEF
    instruction which turns into an architecture-specific illegal
    instruction. Our compiler doesn't do this.
    
    Reviewed-on: https://go-review.googlesource.com/c/159437

From-SVN: r268358
2019-01-29 00:49:23 +00:00
Ian Lance Taylor ea31c98dab libgo: fix building, and some testing, on Solaris
Restore some of the fixes that were applied to golang_org/x/net/lif
    but were lost when 1.12 moved the directory to internal/x/net/lif.
    
    Add support for reading /proc to fetch argc/argv/env for c-archive mode.
    
    Reviewed-on: https://go-review.googlesource.com/c/158640

From-SVN: r268130
2019-01-21 23:05:52 +00:00
Ian Lance Taylor 4f4a855d82 libgo: update to Go1.12beta2
Reviewed-on: https://go-review.googlesource.com/c/158019

gotools/:
	* Makefile.am (go_cmd_vet_files): Update for Go1.12beta2 release.
	(GOTOOLS_TEST_TIMEOUT): Increase to 600.
	(check-runtime): Export LD_LIBRARY_PATH before computing GOARCH
	and GOOS.
	(check-vet): Copy golang.org/x/tools into check-vet-dir.
	* Makefile.in: Regenerate.

gcc/testsuite/:
	* go.go-torture/execute/names-1.go: Stop using debug/xcoff, which
	is no longer externally visible.

From-SVN: r268084
2019-01-18 19:04:36 +00:00
Ian Lance Taylor 33a5d8ccb5 runtime: in doscanstackswitch, set gp->m before gogo
This is following CL 156038. doscanstackswitch uses the same
    mechanism of switching goroutines as getTraceback, and so has
    the same problem as described in issue golang/go#29448. This CL
    applies the same fix.
    
    Reviewed-on: https://go-review.googlesource.com/c/156697

From-SVN: r267661
2019-01-07 22:07:26 +00:00
Ian Lance Taylor 575eb8f58b runtime: in getTraceback, set gp->m before gogo
Currently, when collecting a traceback for another goroutine,
    getTraceback calls gogo(gp) switching to gp, which will resume in
    mcall, which will call gtraceback, which will set up gp->m. There
    is a gap between setting the current running g to gp and setting
    gp->m. If a profiling signal arrives in between, sigtramp will
    see a non-nil gp with a nil m, and will seg fault. Fix this by
    setting up gp->m first.
    
    Fixes golang/go#29448.
    
    Reviewed-on: https://go-review.googlesource.com/c/156038

From-SVN: r267658
2019-01-07 20:12:39 +00:00
Ian Lance Taylor f6be1179bb runtime: prevent deadlock when profiling signal arrives during traceback
Traceback routines, e.g. callers and funcentry, may call
    __go_get_backtrace_state. If a profiling signal arrives while we
    are in the critical section of __go_get_backtrace_state, it tries
    to do a traceback, which also calls __go_get_backtrace_state,
    which tries to enter the same critical section and will deadlock.
    Prevent this deadlock by setting up runtime_in_callers before
    calling __go_get_backtrace_state.
    
    Found while investigating golang/go#29448. Will add a test in the
    next CL.
    
    Updates golang/go#29448.
    
    Reviewed-on: https://go-review.googlesource.com/c/156037

From-SVN: r267590
2019-01-05 00:40:04 +00:00
Ian Lance Taylor e20bfbd18e runtime: prevent deadlock when profiling signal arrives in stack scan
Precise stack scan needs to unwind the stack. When it is
    unwinding the stack, if a profiling signal arrives, which also
    does a traceback, it may deadlock in dl_iterate_phdr. Prevent
    this deadlock by setting up runtime_in_callers before traceback.
    
    Reviewed-on: https://go-review.googlesource.com/c/155766

From-SVN: r267457
2018-12-29 00:07:06 +00:00
Ian Lance Taylor f1410e7e2e runtime: let ARM32 EABI personality function continue unwind when called from traceback
On ARM32 EABI, unlike other platforms, the personality function is
    called during _Unwind_Backtrace (libgcc/unwind-arm-common.inc:581).
    In this case, simply unwind the frame without returning any
    handlers. Otherwise traceback will loop if there is a frame with
    a defer on stack.
    
    Reviewed-on: https://go-review.googlesource.com/c/155759

From-SVN: r267434
2018-12-27 16:31:50 +00:00
Ian Lance Taylor 75e479a8b5 runtime: on ARM32 EABI, don't get LSDA if compact model is used
On ARM32 EABI, when the "compact" unwinding model is used, it
    does not have standard LSDA and _Unwind_GetLanguageSpecificData
    will not return data that is parseable by us. Check this
    conditon before calling _Unwind_GetLanguageSpecificData.
    
    Fix ARM32 build.
    
    Reviewed-on: https://go-review.googlesource.com/c/155758

From-SVN: r267428
2018-12-27 03:13:11 +00:00
Ian Lance Taylor e7db55f636 runtime: handle DW_EH_PE_absptr in type table encoding
The type table encoding can be DW_EH_PE_absptr, but this case
    was missing, which was causing abort on ARM32 EABI. Add the
    missing case.
    
    Reviewed-on: https://go-review.googlesource.com/c/153857

From-SVN: r267070
2018-12-12 23:26:58 +00:00
Ian Lance Taylor be68937be2 runtime: use _URC_FAILURE on ARM32
ARM32 EABI unwinder does not define _URC_NORMAL_STOP. Instead,
    it has _URC_FAILURE. Use _URC_FAILURE there.
    
    Should fix ARM32 build.
    
    Reviewed-on: https://go-review.googlesource.com/c/153417

From-SVN: r267033
2018-12-11 20:50:59 +00:00
Ian Lance Taylor c43137e800 runtime: add precise stack scan support
This CL adds support of precise stack scan using stack maps to
    the runtime. The stack maps are generated by the compiler (if
    supported). Each safepoint is associated with a (real or dummy)
    landing pad, and its "type info" in the exception table is a
    pointer to the stack map. When a stack is scanned, the stack map
    is found by the stack unwinding code by inspecting the exception
    table (LSDA).
    
    For precise stack scan we need to unwind the stack. There are
    three cases:
    
    - If a goroutine is scanning its own stack, it can unwind the
      stack and scan the frames.
    
    - If a goroutine is scanning another, stopped, goroutine, it
      cannot directly unwind the target stack. We handle this by
      switching (runtime.gogo) to the target g, letting it unwind
      and scan the stack, and switch back.
    
    - If we are scanning a goroutine that is blocked in a syscall,
      we send a signal to the target goroutine's thread, and let the
      signal handler unwind and scan the stack. Extra care is needed
      as this races with enter/exit syscall.
    
    Currently this is only implemented on linux.
    
    Reviewed-on: https://go-review.googlesource.com/c/140518

From-SVN: r266832
2018-12-05 23:09:51 +00:00
Ian Lance Taylor 1b28253347 runtime: add arm64 version of AES hash code
Rewrite the arm64 AES hashing code from gc assembler to C code using
    intrinsics.  The resulting code generates the same hash code for the
    same input as the gc code--that doesn't matter as such, but testing it
    ensures that the C code does something useful.
    
    Reviewed-on: https://go-review.googlesource.com/138535

From-SVN: r264771
2018-10-01 20:14:29 +00:00
Ian Lance Taylor dd931d9b48 libgo: update to Go 1.11
Reviewed-on: https://go-review.googlesource.com/136435

gotools/:
	* Makefile.am (mostlyclean-local): Run chmod on check-go-dir to
	make sure it is writable.
	(check-go-tools): Likewise.
	(check-vet): Copy internal/objabi to check-vet-dir.
	* Makefile.in: Rebuild.

From-SVN: r264546
2018-09-24 21:46:21 +00:00
Ian Lance Taylor f0d89c7759 runtime: avoid write barriers with traceback info
Unlike the gc runtime, libgo stores traceback information in location
    structs, which contain strings.  Therefore, copying location structs
    around appears to require write barriers, although in fact write
    barriers are never important because the strings are never allocated
    in Go memory.  They come from libbacktrace.
    
    Some of the generated write barriers come at times when write barriers
    are not permitted.  For example, exitsyscall, marked
    nowritebarrierrec, calls exitsyscallfast which calls traceGoSysExit
    which calls traceEvent which calls traceStackID which calls
    trace.stackTab.put which copies location values into memory allocated
    by tab.newStack.  This write barrier can be invoked when there is no
    p, causing a crash.
    
    This change fixes the problem by ensuring that location values are
    copied around in the tracing code with no write barriers.
    
    This was found by fixing the compiler to fully implement
    //go:nowritebarrierrec; CL to follow.
    
    Reviewed-on: https://go-review.googlesource.com/134226

From-SVN: r264282
2018-09-13 17:30:00 +00:00
Ian Lance Taylor 1d29bb0408 runtime: remove the dummy arg of getcallersp
This is a port of https://golang.org/cl/109596 to the gofrontend, in
    preparation for updating libgo to 1.11.
    
    Original CL description:
    
        getcallersp is intrinsified, and so the dummy arg is no longer
        needed. Remove it, as well as a few dummy args that are solely
        to feed getcallersp.
    
    Reviewed-on: https://go-review.googlesource.com/131116

From-SVN: r263840
2018-08-24 18:15:04 +00:00
Ian Lance Taylor 94e12bd4d9 runtime: don't stat a NULL filename
Noticed in https://gcc.gnu.org/PR86331.
    
    Reviewed-on: https://go-review.googlesource.com/121417

From-SVN: r262234
2018-06-28 20:54:04 +00:00
Ian Lance Taylor 88d51f7996 runtime: use #ifdef instead of #if for USING_SPLIT_STACK
USING_SPLIT_STACK is configured as defined/undefined, not 0/1.
    Most of the places test USING_SPLIT_STACK with #ifdef, with a
    few exceptions. This CL fixes the exceptions.
    
    Reviewed-on: https://go-review.googlesource.com/120596

From-SVN: r261980
2018-06-23 02:44:36 +00:00
Ian Lance Taylor 772455c964 libgo: fix for unaligned read in go-unwind.c's read_encoded_value()
Change code to work properly reading unaligned data on architectures
    that don't support unaliged reads. This fixes a regression (broke
    Solaris/sparc) introduced in https://golang.org/cl/90235.
    
    Reviewed-on: https://go-review.googlesource.com/111296

From-SVN: r259935
2018-05-04 14:29:05 +00:00
Ian Lance Taylor 019808c95c libgo: break dependence on libgcc unwind-pe.h
The C portion of the Go runtime includes the header "unwind-pe.h" from
    libgcc, which contains some constants and a few small routines for
    decoding pointer values within unwind info. This patch gets rid of
    that include and instead adds a re-implementation of that
    functionality in the single file that uses it. The intent is to allow
    the C runtime portion of libgo to be built without a companion GCC
    installation.
    
    Reviewed-on: https://go-review.googlesource.com/90235

From-SVN: r259861
2018-05-02 21:53:30 +00:00
Ian Lance Taylor 2dab5d909f runtime: use a fence instruction before rdtsc
This implements the same choices made in the gc runtime, except that
    for 32-bit x86 we only use the fence instruction if the processor
    supports SSE2.
    
    The code here is hacked up for speed; the gc runtime uses straight
    assembler.
    
    Reviewed-on: https://go-review.googlesource.com/97715

From-SVN: r258336
2018-03-07 14:31:03 +00:00
Ian Lance Taylor afedc99bd2 runtime: funcfileline: get missing function name from symbol table
Copy the idea of https://golang.org/cl/92756 to funcfileline, which is
    used by runtime.FuncForPC, runtime.(*Frames).Next, and others.
    
    Reviewed-on: https://go-review.googlesource.com/96175

From-SVN: r257913
2018-02-22 18:52:33 +00:00
Ian Lance Taylor 74e6f14adb runtime: get missing function name from symbol table
If we trace back through code that has no debug info, as when calling
    through C code compiled with -g0, we won't have a function name.
    Try to fetch the function name using the symbol table.
    
    Adding the test case revealed that gotest failed to use the gccgo tag
    when matching files, so add that.
    
    Reviewed-on: https://go-review.googlesource.com/92756

From-SVN: r257495
2018-02-08 15:37:43 +00:00
Ian Lance Taylor 38f08ec0bd runtime: scan register backing store on ia64
On ia64, a separate stack is used for saving/restoring register frames,
    occupying the other end of the stack mapping. This must also be scanned
    for pointers into the heap.
    
    Reviewed-on: https://go-review.googlesource.com/85276

From-SVN: r257323
2018-02-02 00:16:43 +00:00
Ian Lance Taylor 9734500e9b runtime: fix type descriptor name in C code
I forgot to update the name of the map[string]bool type descriptor
    used in go-fieldtrack.c.  This didn't cause any errors because it's a
    weak symbol, and the current testsuite has no field tracking tests.
    
    Reviewed-on: https://go-review.googlesource.com/91096

From-SVN: r257249
2018-01-31 18:25:17 +00:00
Ian Lance Taylor 4880b994d6 compiler: rationalize external symbol names
Encode all external symbol names using only ASCII alphanumeric
    characters, underscore, and dot.  Use a scheme that can be reliably
    demangled to a somewhat readable version as described in the long
    comment in names.cc.
    
    A minor cleanup discovered during this was that we were treating
    function types as different if one had a NULL parameters_ field and
    another has a non-NULL parameters_ field that has no parameters.  This
    worked because we mangled them slightly differently.  We now mangle
    them the same, so we treat them as equal, as we should anyhow.
    
    Reviewed-on: https://go-review.googlesource.com/89555

	* go.go-torture/execute/names-1.go: New test.

From-SVN: r257033
2018-01-24 23:50:09 +00:00
Ian Lance Taylor 389578d7a6 re PR c/82922 (Request: add -Wstrict-prototypes to -Wextra as K&R style is obsolescent)
PR c/82922

    runtime, syscall: use full prototypes in C code
    
    Based on patch by Martin Sebor.
    
    Reviewed-on: https://go-review.googlesource.com/86815

From-SVN: r256437
2018-01-10 15:42:23 +00:00
Ian Lance Taylor c9edeca8b8 runtime: fix makemap calls in __go_construct_map
The signature of makemap changed with the update to 1.10beta1,
    but I forgot to update the call from C code.
    
    Reviewed-on: https://go-review.googlesource.com/87135

From-SVN: r256431
2018-01-10 15:04:21 +00:00
Ian Lance Taylor 1a2f01efa6 libgo: update to Go1.10beta1
Update the Go library to the 1.10beta1 release.
    
    Requires a few changes to the compiler for modifications to the map
    runtime code, and to handle some nowritebarrier cases in the runtime.
    
    Reviewed-on: https://go-review.googlesource.com/86455

gotools/:
	* Makefile.am (go_cmd_vet_files): New variable.
	(go_cmd_buildid_files, go_cmd_test2json_files): New variables.
	(s-zdefaultcc): Change from constants to functions.
	(noinst_PROGRAMS): Add vet, buildid, and test2json.
	(cgo$(EXEEXT)): Link against $(LIBGOTOOL).
	(vet$(EXEEXT)): New target.
	(buildid$(EXEEXT)): New target.
	(test2json$(EXEEXT)): New target.
	(install-exec-local): Install all $(noinst_PROGRAMS).
	(uninstall-local): Uninstasll all $(noinst_PROGRAMS).
	(check-go-tool): Depend on $(noinst_PROGRAMS).  Copy down
	objabi.go.
	(check-runtime): Depend on $(noinst_PROGRAMS).
	(check-cgo-test, check-carchive-test): Likewise.
	(check-vet): New target.
	(check): Depend on check-vet.  Look at cmd_vet-testlog.
	(.PHONY): Add check-vet.
	* Makefile.in: Rebuild.

From-SVN: r256365
2018-01-09 01:23:08 +00:00
Ian Lance Taylor 5ac29058f0 sync/atomic, runtime/internal/atomic: don't assume reads from 0 fail
For a misaligned address force a panic rather than assuming that reading
    from the address 0 will cause one.
    
    Reviewed-on: https://go-review.googlesource.com/69850

From-SVN: r254610
2017-11-09 21:56:59 +00:00
Ian Lance Taylor 3ff1b2b0a9 runtime: fix issues on AIX about uintptr(_t)
Reviewed-on: https://go-review.googlesource.com/69891

From-SVN: r253664
2017-10-11 21:16:49 +00:00
Ian Lance Taylor 4d034b5259 runtime: always initialize str field in __go_string_slice result
Reviewed-on: https://go-review.googlesource.com/64110

From-SVN: r252953
2017-09-18 22:29:45 +00:00
Ian Lance Taylor bc998d034f libgo: update to go1.9
Reviewed-on: https://go-review.googlesource.com/63753

From-SVN: r252767
2017-09-14 17:11:35 +00:00
Ian Lance Taylor 6fa7df983e runtime: make go-nosys.c compile with !HAVE_SYSCALL
Reviewed-on: https://go-review.googlesource.com/59910

From-SVN: r251435
2017-08-29 20:57:20 +00:00
Ian Lance Taylor b66d36128f re PR go/81893 (compilation error in libgo starting with r251127)
PR go/81893
    runtime: only use PPC GNU/Linux register code on little endian
    
    Reportedly the current code builds on little endian but not big endian.
    
    Fixes https://gcc.gnu.org/PR81893.
    
    Reviewed-on: https://go-review.googlesource.com/57110

From-SVN: r251188
2017-08-18 20:17:26 +00:00
Ian Lance Taylor 450f20a899 runtime: improvements for signal registers
Fix dumpregs on i386, implement dumpregs for PPC Linux/AIX, get PC on AIX.
    
    Reviewed-on: https://go-review.googlesource.com/56170

From-SVN: r251127
2017-08-16 19:04:00 +00:00
Ian Lance Taylor 8ffe2be85e runtime: dump registers for Alpha
Patch from Uros Bizjak.
    
    Reviewed-on: https://go-review.googlesource.com/53350

From-SVN: r250873
2017-08-04 13:46:39 +00:00
Ian Lance Taylor 993323a14f runtime: handle Alpha GNU/Linux in getSiginfo
Patch by Uros Bizjak.
    
    Reviewed-on: https://go-review.googlesource.com/51370

From-SVN: r250588
2017-07-26 20:20:22 +00:00
Ian Lance Taylor df206c6e77 runtime: don't use runtime_lock in __go_get_backtrace_state
If getSiginfo does not know how to determine the PC, it will call
    runtime_callers. That can happen in a thread that was started by
    non-Go code, in which case the TLS variable g will not be set, in
    which case runtime_lock will crash.
    
    Avoid the problem by using atomic operations for the lock. This is OK
    since creating a backtrace state is fast and never blocks.
    
    The test case is TestCgoExternalThreadSIGPROF in the runtime package
    on a system that getSiginfo doesn't handle specially.
    
    Updates golang/go#20931
    
    Reviewed-on: https://go-review.googlesource.com/50650

From-SVN: r250439
2017-07-21 18:27:35 +00:00
Ian Lance Taylor 0ab7176094 runtime: handle PPC/PPC64 GNU/Linux in getSiginfo
Updates golang/go#20931
    
    Reviewed-on: https://go-review.googlesource.com/50631

From-SVN: r250436
2017-07-21 18:08:01 +00:00
Ian Lance Taylor 9e45ca5f83 re PR go/81451 (missing futex check - libgo/runtime/thread-linux.c:12:0 futex.h:13:12: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘long’)
PR go/81451
    runtime: inline runtime_osinit
    
    We had two identical copies of runtime_osinit. They set runtime_ncpu,
    a variable that is no longer used. Removing that leaves us with two lines.
    Inline those two lines in the two places the function was called.
    
    This fixes GCC PR 81451.
    
    Reviewed-on: https://go-review.googlesource.com/48862

From-SVN: r250326
2017-07-18 23:14:29 +00:00