BFD ld (and the other linkers) only produce one encoding of these
values. It is not necessary to use the general
read_encoded_value_with_base decoding routine. This avoids the
data-dependent branches in its implementation.
libgcc/
* unwind-dw2-fde-dip.c (find_fde_tail): Special-case encoding
values actually used by BFD ld.
'libobjc/thr.c' includes 'gthr.h'. While all the other gthread headers
have `#ifdef _LIBOBJC` checks, and provide a different set of inline
functions, I think having one header provide two completely unrelated
set of APIs is unsatisfactory, complicates maintenance, and hinders
further development.
This commit references a new header for libobjc, and adds a copyright
notice, as in other headers.
libgcc/ChangeLog:
* config/i386/gthr-mcf.h: Include 'gthr_libobjc.h' when building
libobjc, instead of 'gthr.h'
This patch adds the new thread model `mcf`, which implements mutexes
and condition variables with the mcfgthread library.
Source code for mcfgthread is available at <https://github.com/lhmouse/mcfgthread>.
config/ChangeLog:
* gthr.m4 (GCC_AC_THREAD_HEADER): Add new case for `mcf` thread
model
gcc/ChangeLog:
* config/i386/mingw-mcfgthread.h: New file
* config/i386/mingw32.h: Add builtin macro and default libraries
for mcfgthread when thread model is `mcf`
* config.gcc: Include 'i386/mingw-mcfgthread.h' when thread model
is `mcf`
* configure.ac: Recognize `mcf` as a valid thread model
* config.in: Regenerate
* configure: Regenerate
libatomic/ChangeLog:
* configure.tgt: Add new case for `mcf` thread model
libgcc/ChangeLog:
* config.host: Add new cases for `mcf` thread model
* config/i386/gthr-mcf.h: New file
* config/i386/t-mingw-mcfgthread: New file
* config/i386/t-slibgcc-cygming: Add mcfgthread for libgcc DLL
* configure: Regenerate
libstdc++-v3/ChangeLog:
* libsupc++/atexit_thread.cc (__cxa_thread_atexit): Use
implementation from mcfgthread if available
* libsupc++/guard.cc (__cxa_guard_acquire, __cxa_guard_release,
__cxa_guard_abort): Use implementations from mcfgthread if
available
* configure: Regenerate
If the xgcc executable has not been built (or has been removed by 'make
clean') then the command to print the multilib dir fails, and so the
MULTIOSDIR variable is empty. That then causes:
/bin/sh: line 0: test: !=: unary operator expected
We can avoid it by quoting the variable.
libgcc/ChangeLog:
* Makefile.in: Quote variable.
If shadow stack is enabled, when unwinding stack, we count how many stack
frames we pop to reach the landing pad and adjust shadow stack by the same
amount. When counting the stack frame, we compare the return address on
normal stack against the return address on shadow stack. If they don't
match, return _URC_FATAL_PHASE2_ERROR for the corrupted return address on
normal stack. Don't check the return address for
1. Non-catchable exception where exception_class == 0. Process will be
terminated.
2. Zero return address which marks the outermost stack frame.
3. Signal stack frame since kernel puts a restore token on shadow stack.
* unwind-generic.h (_Unwind_Frames_Increment): Add the EXC
argument.
* unwind.inc (_Unwind_RaiseException_Phase2): Pass EXC to
_Unwind_Frames_Increment.
(_Unwind_ForcedUnwind_Phase2): Likewise.
* config/i386/shadow-stack-unwind.h (_Unwind_Frames_Increment):
Take the EXC argument. Return _URC_FATAL_PHASE2_ERROR if the
return address on normal stack doesn't match the return address
on shadow stack.
On many architectures, there is a padding gap after the how array
member, and cfa_how can be moved there. This reduces the size of the
struct and the amount of memory that uw_frame_state_for has to clear.
There is no measurable performance benefit from this on x86-64 (even
though the memset goes from 120 to 112 bytes), but it seems to be a
good idea to do anyway.
libgcc/
* unwind-dw2.h (struct frame_state_reg_info): Move cfa_how member
and reduce its size.
Here is a complete patch to add std::bfloat16_t support on
x86 (AArch64 and ARM left for later). Almost no BFmode optabs
are added by the patch, so for binops/unops it extends to SFmode
first and then truncates back to BFmode.
For {HF,SF,DF,XF,TF}mode -> BFmode conversions libgcc has implementations
of all those conversions so that we avoid double rounding, for
BFmode -> {DF,XF,TF}mode conversions to avoid growing libgcc too much
it emits BFmode -> SFmode conversion first and then converts to the even
wider mode, neither step should be imprecise.
For BFmode -> HFmode, it first emits a precise BFmode -> SFmode conversion
and then SFmode -> HFmode, because neither format is subset or superset
of the other, while SFmode is superset of both.
expr.cc then contains a -ffast-math optimization of the BF -> SF and
SF -> BF conversions if we don't optimize for space (and for the latter
if -frounding-math isn't enabled either).
For x86, perhaps truncsfbf2 optab could be defined for TARGET_AVX512BF16
but IMNSHO should FAIL if !flag_finite_math || flag_rounding_math
|| !flag_unsafe_math_optimizations, because I think the insn doesn't
raise on sNaNs, hardcodes round to nearest and flushes denormals to zero.
By default (unless x86 -fexcess-precision=16) we use float excess
precision for BFmode, so truncate only on explicit casts and assignments.
The patch introduces a single __bf16 builtin - __builtin_nansf16b,
because (__bf16) __builtin_nansf ("") will drop the sNaN into qNaN,
and uses f16b suffix instead of bf16 because there would be ambiguity on
log vs. logb - __builtin_logbf16 could be either log with bf16 suffix
or logb with f16 suffix. In other cases libstdc++ should mostly use
__builtin_*f for std::bfloat16_t overloads (we have a problem with
std::nextafter though but that one we have also for std::float16_t).
2022-10-14 Jakub Jelinek <jakub@redhat.com>
gcc/
* tree-core.h (enum tree_index): Add TI_BFLOAT16_TYPE.
* tree.h (bfloat16_type_node): Define.
* tree.cc (excess_precision_type): Promote bfloat16_type_mode
like float16_type_mode.
(build_common_tree_nodes): Initialize bfloat16_type_node if
BFmode is supported.
* expmed.h (maybe_expand_shift): Declare.
* expmed.cc (maybe_expand_shift): No longer static.
* expr.cc (convert_mode_scalar): Don't ICE on BF -> HF or HF -> BF
conversions. If there is no optab, handle BF -> {DF,XF,TF,HF}
conversions as separate BF -> SF -> {DF,XF,TF,HF} conversions, add
-ffast-math generic implementation for BF -> SF and SF -> BF
conversions.
* builtin-types.def (BT_BFLOAT16, BT_FN_BFLOAT16_CONST_STRING): New.
* builtins.def (BUILT_IN_NANSF16B): New builtin.
* fold-const-call.cc (fold_const_call): Handle CFN_BUILT_IN_NANSF16B.
* config/i386/i386.cc (classify_argument): Handle E_BCmode.
(ix86_libgcc_floating_mode_supported_p): Also return true for BFmode
for -msse2.
(ix86_mangle_type): Mangle BFmode as DF16b.
(ix86_invalid_conversion, ix86_invalid_unary_op,
ix86_invalid_binary_op): Remove.
(TARGET_INVALID_CONVERSION, TARGET_INVALID_UNARY_OP,
TARGET_INVALID_BINARY_OP): Don't redefine.
* config/i386/i386-builtins.cc (ix86_bf16_type_node): Remove.
(ix86_register_bf16_builtin_type): Use bfloat16_type_node rather than
ix86_bf16_type_node, only create it if still NULL.
* config/i386/i386-builtin-types.def (BFLOAT16): Likewise.
* config/i386/i386.md (cbranchbf4, cstorebf4): New expanders.
gcc/c-family/
* c-cppbuiltin.cc (c_cpp_builtins): If bfloat16_type_node,
predefine __BFLT16_*__ macros and for C++23 also
__STDCPP_BFLOAT16_T__. Predefine bfloat16_type_node related
macros for -fbuilding-libgcc.
* c-lex.cc (interpret_float): Handle CPP_N_BFLOAT16.
gcc/c/
* c-typeck.cc (convert_arguments): Don't promote __bf16 to
double.
gcc/cp/
* cp-tree.h (extended_float_type_p): Return true for
bfloat16_type_node.
* typeck.cc (cp_compare_floating_point_conversion_ranks): Set
extended{1,2} if mv{1,2} is bfloat16_type_node. Adjust comment.
gcc/testsuite/
* lib/target-supports.exp (check_effective_target_bfloat16,
check_effective_target_bfloat16_runtime, add_options_for_bfloat16):
New.
* gcc.dg/torture/bfloat16-basic.c: New test.
* gcc.dg/torture/bfloat16-builtin.c: New test.
* gcc.dg/torture/bfloat16-builtin-issignaling-1.c: New test.
* gcc.dg/torture/bfloat16-complex.c: New test.
* gcc.dg/torture/builtin-issignaling-1.c: Allow to be includable
from bfloat16-builtin-issignaling-1.c.
* gcc.dg/torture/floatn-basic.h: Allow to be includable from
bfloat16-basic.c.
* gcc.target/i386/vect-bfloat16-typecheck_2.c: Adjust expected
diagnostics.
* gcc.target/i386/sse2-bfloat16-scalar-typecheck.c: Likewise.
* gcc.target/i386/vect-bfloat16-typecheck_1.c: Likewise.
* g++.target/i386/bfloat_cpp_typecheck.C: Likewise.
libcpp/
* include/cpplib.h (CPP_N_BFLOAT16): Define.
* expr.cc (interpret_float_suffix): Handle bf16 and BF16 suffixes for
C++.
libgcc/
* config/i386/t-softfp (softfp_extensions): Add bfsf.
(softfp_truncations): Add tfbf xfbf dfbf sfbf hfbf.
(CFLAGS-extendbfsf2.c, CFLAGS-truncsfbf2.c, CFLAGS-truncdfbf2.c,
CFLAGS-truncxfbf2.c, CFLAGS-trunctfbf2.c, CFLAGS-trunchfbf2.c): Add
-msse2.
* config/i386/libgcc-glibc.ver (GCC_13.0.0): Export
__extendbfsf2 and __trunc{s,d,x,t,h}fbf2.
* config/i386/sfp-machine.h (_FP_NANSIGN_B): Define.
* config/i386/64/sfp-machine.h (_FP_NANFRAC_B): Define.
* config/i386/32/sfp-machine.h (_FP_NANFRAC_B): Define.
* soft-fp/brain.h: New file.
* soft-fp/truncsfbf2.c: New file.
* soft-fp/truncdfbf2.c: New file.
* soft-fp/truncxfbf2.c: New file.
* soft-fp/trunctfbf2.c: New file.
* soft-fp/trunchfbf2.c: New file.
* soft-fp/truncbfhf2.c: New file.
* soft-fp/extendbfsf2.c: New file.
libiberty/
* cp-demangle.h (D_BUILTIN_TYPE_COUNT): Increment.
* cp-demangle.c (cplus_demangle_builtin_types): Add std::bfloat16_t
entry.
(cplus_demangle_type): Demangle DF16b.
* testsuite/demangle-expected (_Z3xxxDF16b): New test.
This change adds the configury bits to activate the build of
shared libs on VxWorks ports configured with --enable-shared,
for libraries variants where this is generally supported (rtp,
code model !large - currently not compatible with -fPIC).
Set lt_cv_deplibs_check_method in libtool.m4, so the build of
libraries know how to establish dependencies. This is useful in
configurations such as aarch64 where proper support of LSE relies
on accurate dependency information between libstdc++ and libgcc_s
to begin with.
Regenerate configure scripts to reflect libtool.m4 change.
2022-10-09 Olivier Hainque <hainque@adacore.com>
* libtool.m4 (*vxworks*): When enable_shared, set dynamic_linker
and friends for rtp !large. Assume the linker has the required
abilities and set lt_cv_deplibs_check_method.
gcc/
* config.gcc (*vxworks*): Add t-slibgcc fragment
if enable_shared.
libgcc/
* config.host (*vxworks*): When enable_shared, add
libgcc and crtstuff "shared" fragments for rtp except
large code model.
(aarch64*-wrs-vxworks7*): Remove t-slibgcc-libgcc from
the list of fragments.
2022-10-09 Olivier Hainque <hainque@adacore.com>
gcc/
* configure: Regenerate.
libatomic/
* configure: Regenerate.
libbacktrace/
* configure: Regenerate.
libcc1/
* configure: Regenerate.
libffi/
* configure: Regenerate.
libgfortran/
* configure: Regenerate.
libgomp/
* configure: Regenerate.
libitm/
* configure: Regenerate.
libobjc/
* configure: Regenerate.
liboffloadmic/
* configure: Regenerate.
liboffloadmic/
* plugin/configure: Regenerate.
libphobos/
* configure: Regenerate.
libquadmath/
* configure: Regenerate.
libsanitizer/
* configure: Regenerate.
libssp/
* configure: Regenerate.
libstdc++-v3/
* configure: Regenerate.
libvtv/
* configure: Regenerate.
lto-plugin/
* configure: Regenerate.
zlib/
* configure: Regenerate.
Missed one spot in the r13-3108-g146e45914032 change (my sed script
didn't expect nested []s).
2022-10-07 Jakub Jelinek <jakub@redhat.com>
* config/arc/linux-unwind.h (arc_fallback_frame_state): Use
fs->regs.how[X] instead of fs->regs.reg[X].how.
The following patch implements something that has Florian found as
low hanging fruit in our unwinder and has been discussed in the
https://gcc.gnu.org/wiki/cauldron2022#cauldron2022talks.inprocess_unwinding_bof
talk.
_Unwind_FrameState type seems to be (unlike the pre-GCC 3 frame_state
which has been part of ABI) private to unwind-dw2.c + unwind.inc it
includes, it is always defined on the stack of some entrypoints, initialized
by static uw_frame_state_for and the address of it is also passed to other
static functions or the static inlines handling machine dependent unwinding,
but it isn't fortunately passed to any callbacks or public functions, so I
think we can safely change it any time we want.
Florian mentioned that the structure is large even on x86_64, 384 bytes
there, starts with 328 bytes long element with frame_state_reg_info type
which then starts with an array with __LIBGCC_DWARF_FRAME_REGISTERS__ + 1
elements, each of them is 16 bytes long, on x86_64
__LIBGCC_DWARF_FRAME_REGISTERS__ is just 17 but even that is big, on say
riscv __LIBGCC_DWARF_FRAME_REGISTERS__ is I think 128, on powerpc 111,
on sh 153 etc. And, we memset to zero the whole fs variable with the
_Unwind_FrameState type at the start of the unwinding.
The reason why each element is 16 byte (on 64-bit arches) is that it
contains some pointer or pointer sized integer and then an enum (with just
7 different enumerators) + padding.
The following patch decreases it by moving the enum into a separate
array and using just one byte for each register in that second array.
We could compress it even more, say 4 bits per register, but I don't
want to uglify the code for it too much and make the accesses slower.
Furthermore, the clearing of the object can clear only thos how array
and members after it, because REG_UNSAVED enumerator (0) doesn't actually
need any pointer or pointer sized integer, it is just the other kinds
that need to have there something.
By doing this, on x86_64 the above numbers change to _Unwind_FrameState
type being now 264 bytes long, frame_state_reg_info 208 bytes and we
don't clear the first 144 bytes of the object, so the memset is 120 bytes,
so ~ 31% of the old clearing size. On riscv 64-bit assuming it has same
structure layout rules for the few types used there that would be
~ 2160 bytes of _Unwind_FrameState type before and ~ 1264 bytes after,
with the memset previously ~ 2160 bytes and after ~ 232 bytes after.
We've also talked about possibly adding a number of initially initialized
regs and initializing the rest lazily, but at least for x86_64 with
18 elements in the array that doesn't seem to be worth it anymore,
especially because return address column is 16 there and that is usually the
first thing to be touched. It might theory help with lots of registers if
they are usually untouched, but would uglify and complicate any stores to
how by having to check there for the not initialized yet cases and lazy
initialization, and similarly for all reads of how to do there if below
last initialized one, use how, otherwise imply REG_UNSAVED.
The disadvantage of the patch is that touching reg[x].loc and how[x]
now means 2 cachelines rather than one as before, and I admit beyond
bootstrap/regtest I haven't benchmarked it in any way.
2022-10-06 Jakub Jelinek <jakub@redhat.com>
* unwind-dw2.h (REG_UNSAVED, REG_SAVED_OFFSET, REG_SAVED_REG,
REG_SAVED_EXP, REG_SAVED_VAL_OFFSET, REG_SAVED_VAL_EXP,
REG_UNDEFINED): New anonymous enum, moved from inside of
struct frame_state_reg_info.
(struct frame_state_reg_info): Remove reg[].how element and the
anonymous enum there. Add how element.
* unwind-dw2.c: Include stddef.h.
(uw_frame_state_for): Don't clear first
offsetof (_Unwind_FrameState, regs.how[0]) bytes of *fs.
(execute_cfa_program, __frame_state_for, uw_update_context_1,
uw_update_context): Use fs->regs.how[X] instead of fs->regs.reg[X].how
or fs.regs.how[X] instead of fs.regs.reg[X].how.
* config/sh/linux-unwind.h (sh_fallback_frame_state): Likewise.
* config/bfin/linux-unwind.h (bfin_fallback_frame_state): Likewise.
* config/pa/linux-unwind.h (pa32_fallback_frame_state): Likewise.
* config/pa/hpux-unwind.h (UPDATE_FS_FOR_SAR, UPDATE_FS_FOR_GR,
UPDATE_FS_FOR_FR, UPDATE_FS_FOR_PC, pa_fallback_frame_state):
Likewise.
* config/alpha/vms-unwind.h (alpha_vms_fallback_frame_state):
Likewise.
* config/alpha/linux-unwind.h (alpha_fallback_frame_state): Likewise.
* config/arc/linux-unwind.h (arc_fallback_frame_state,
arc_frob_update_context): Likewise.
* config/riscv/linux-unwind.h (riscv_fallback_frame_state): Likewise.
* config/nios2/linux-unwind.h (NIOS2_REG): Likewise.
* config/nds32/linux-unwind.h (NDS32_PUT_FS_REG): Likewise.
* config/s390/tpf-unwind.h (s390_fallback_frame_state): Likewise.
* config/s390/linux-unwind.h (s390_fallback_frame_state): Likewise.
* config/sparc/sol2-unwind.h (sparc64_frob_update_context,
MD_FALLBACK_FRAME_STATE_FOR): Likewise.
* config/sparc/linux-unwind.h (sparc64_fallback_frame_state,
sparc64_frob_update_context, sparc_fallback_frame_state): Likewise.
* config/i386/sol2-unwind.h (x86_64_fallback_frame_state,
x86_fallback_frame_state): Likewise.
* config/i386/w32-unwind.h (i386_w32_fallback_frame_state): Likewise.
* config/i386/linux-unwind.h (x86_64_fallback_frame_state,
x86_fallback_frame_state): Likewise.
* config/i386/freebsd-unwind.h (x86_64_freebsd_fallback_frame_state):
Likewise.
* config/i386/dragonfly-unwind.h
(x86_64_dragonfly_fallback_frame_state): Likewise.
* config/i386/gnu-unwind.h (x86_gnu_fallback_frame_state): Likewise.
* config/csky/linux-unwind.h (csky_fallback_frame_state): Likewise.
* config/aarch64/linux-unwind.h (aarch64_fallback_frame_state):
Likewise.
* config/aarch64/freebsd-unwind.h
(aarch64_freebsd_fallback_frame_state): Likewise.
* config/aarch64/aarch64-unwind.h (aarch64_frob_update_context):
Likewise.
* config/or1k/linux-unwind.h (or1k_fallback_frame_state): Likewise.
* config/mips/linux-unwind.h (mips_fallback_frame_state): Likewise.
* config/loongarch/linux-unwind.h (loongarch_fallback_frame_state):
Likewise.
* config/m68k/linux-unwind.h (m68k_fallback_frame_state): Likewise.
* config/xtensa/linux-unwind.h (xtensa_fallback_frame_state):
Likewise.
* config/rs6000/darwin-fallback.c (set_offset): Likewise.
* config/rs6000/aix-unwind.h (MD_FROB_UPDATE_CONTEXT): Likewise.
* config/rs6000/linux-unwind.h (ppc_fallback_frame_state): Likewise.
* config/rs6000/freebsd-unwind.h (frob_update_context): Likewise.
Investigating the reasons for libgcc build failures in a canadian
context, orthogonally to the recent update of vxcrtstuff, exposed
interesting differences in the way include search paths are managed
between a regular Linux->VxWorks cross build and a canadian setup
building a Windows->VxWorks toolchain in a Linux environment.
This change augments the comment attached to LIBGCC2_INCLUDE in
libgcc/config/t-vxworks to better describe the parameters at play.
It also adjusts the addition of options for gcc/include and
gcc/include-fixed to minimize the actual differences for libgcc
in the two kinds of configurations.
2022-03-06 Olivier Hainque <hainque@adacore.com>
libgcc/
* config/t-vxworks (LIBGCC2_INCLUDE): Augment comment. Move
-I options for gcc/include and gcc/include-fixed at the end
and make them -isystem.
Within gthr-vxworks.h, we prevent C++ errors from missing
declarations in some system headers by prepending their inclusion
with a
#pragma GCC diagnostic ignored "-Wstrict-prototypes"
But Wstrict-prototypes is internally registered as valid for
C/ObjC only, not C++, and this trick in turn triggers a Wpragma
warning with -Wsystem-headers.
This change just arranges to ignore the secondary warning locally.
2021-02-03 Olivier Hainque <hainque@adacore.com>
* config/gthr-vxworks.h: Prevent Wpragma warning for the
pragma diagnostics on Wstrict-prototypes.
This change augments the comment attached to the use of auto-host.h
in vxcrtstuff.c to better describe the reason for including it and
for the associated series of #undef directives.
It also augments the comment on dso_handle and removes a redundant
guard on HAVE_INITFINI_ARRAY_SUPPORT for the shared version of the
objects, nested within a section guarded on USE_INITFINI_ARRAY.
2022-09-29 Olivier Hainque <hainque@adacore.com>
libgcc/
* config/vxcrtstuff.c: Improve the comment attached to the use
of auto-host.h and of __dso_handle. Remove redundant guard on
HAVE_INITFINI_ARRAY_SUPPORT within a USE_INITFINI_ARRAY section.
When using the atomic fast path deregistering can fail during
program shutdown if the lookup structures are already destroyed.
The assert in __deregister_frame_info_bases takes that into
account. In the non-fast-path case however is not aware of
program shutdown, which caused a compiler error on such platforms.
We fix that by introducing a constant for in_shutdown in
non-fast-path builds.
We also drop the destructor priority, as it is not supported on
all platforms and we no longer rely upon the priority anyway.
libgcc/ChangeLog:
* unwind-dw2-fde.c: Introduce a constant for in_shutdown
for the non-fast-path case. Drop destructor priority.
In some scenarios (e.g., when mixing gcc and clang code), it can
happen that frames are deregistered after the lookup structure
has already been destroyed. That in itself would be fine, but
it triggers an assert in __deregister_frame_info_bases that
expects to find the frame.
To avoid that, we now remember that the btree as already been
destroyed and disable the assert in that case.
libgcc/ChangeLog:
* unwind-dw2-fde.c: (release_register_frames) Remember
when the btree has been destroyed.
(__deregister_frame_info_bases) Disable the assert when
shutting down.
this patch fixed PR target/99184 which incorrectly rounded during 64-bit
(long) double to 16-bit and 32-bit integers.
The patch just removes the respective roundings from
libf7-asm.sx::to_integer and ::to_unsigned. Luckily, LibF7 does nowhere
use respective functions internally, the only user is in libf7.c::f7_exp
which reads
f7_round (qq, qq);
int16_t q = f7_get_s16 (qq);
so that f7_get_s16() operates on an already rounded value, and therefore
this code works unaltered with or without rounding in to_integer.
PR target/99184
libgcc/config/avr/libf7/
* libf7-asm.sx (to_integer, to_unsigned): Don't round 16-bit
and 32-bit integers.
uintptr_t is no available for all targets, use __UINTPTR_TYPE__
instead.
libgcc/ChangeLog:
* unwind-dw2-fde.c: Replace uintptr_t with typedef
for __UINTPTR_TYPE__.
* unwind-dw2-btree.h: Likewise.
The __register_frame/__deregister_frame functions are used to register
unwinding frames from JITed code in a sorted list. That list itself
is protected by object_mutex, which leads to terrible performance
in multi-threaded code and is somewhat expensive even if single-threaded.
There was already a fast-path that avoided taking the mutex if no
frame was registered at all.
This commit eliminates both the mutex and the sorted list from
the atomic fast path, and replaces it with a btree that uses
optimistic lock coupling during lookup. This allows for fully parallel
unwinding and is essential to scale exception handling to large
core counts.
libgcc/ChangeLog:
* unwind-dw2-fde.c (release_registered_frames): Cleanup at shutdown.
(__register_frame_info_table_bases): Use btree in atomic fast path.
(__deregister_frame_info_bases): Likewise.
(_Unwind_Find_FDE): Likewise.
(base_from_object): Make parameter const.
(classify_object_over_fdes): Add query-only mode.
(get_pc_range): Compute PC range for lookup.
* unwind-dw2-fde.h (last_fde): Make parameter const.
* unwind-dw2-btree.h: New file.
The ARC soft udivmodsi4 algorithm and as well as using umodsi3
for reduced register set configurations are wrong.
libgcc/
* config/arc/lib2funcs.c (udivmodsi4): Update AND mask.
* config/arc/lib1funcs.S (umodsi3): Don't use it for RF16
configurations.
> (clrsb:m x)
> Represents the number of redundant leading sign bits in x, represented
> as an integer of mode m, starting at the most significant bit position.
This explanation is just what the NSA instruction (not ever emitted before)
calculates in Xtensa ISA.
gcc/ChangeLog:
* config/xtensa/xtensa.md (clrsbsi2): New insn pattern.
libgcc/ChangeLog:
* config/xtensa/lib1funcs.S (__clrsbsi2): New function.
* config/xtensa/t-xtensa (LIB1ASMFUNCS): Add _clrsbsi2.
