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Author SHA1 Message Date
Victor Do Nascimento
f6b9a064a2 Libatomic: AArch64: Convert all lse128 assembly to .insn directives 
Given the lack of support for the LSE128 instructions in all but the
the most up-to-date version of Binutils (2.42), having the build-time
test for assembler support for these instructions often leads to the
building of Libatomic without support for LSE128-dependent atomic
function implementations.  This ultimately leads to different people
having different versions of Libatomic on their machines, depending on
which assembler was available at compilation time.

Furthermore, the conditional inclusion of these atomic function
implementations predicated on assembler support leads to a series of
`#if HAVE_FEAT_LSE128' guards scattered throughout the codebase and
the need for a series of aliases when the feature flag evaluates
to false.  The preprocessor macro guards, together with the
conditional aliasing leads to code that is cumbersome to understand
and maintain.

Both of the issues highlighted above will only get worse with the
coming support for LRCPC3 atomics which under the current scheme will
also require build-time checks.

Consequently, a better option for both consistency across builds and
code cleanness is to make recourse to the `.inst' directive.  By
replacing all novel assembly instructions for their hexadecimal
representation within `.inst's, we ensure that the Libatomic code is
both considerably cleaner and all machines build the same binary,
irrespective of binutils version available at compile time.

This patch therefore removes all configure checks for LSE128-support
in the assembler and all the guards and aliases that were associated
with `HAVE_FEAT_LSE128'

libatomic/ChangeLog:

	* acinclude.m4 (LIBAT_TEST_FEAT_AARCH64_LSE128): Delete.
	* auto-config.h.in (HAVE_FEAT_LSE128): Likewise
	* config/linux/aarch64/atomic_16.S: Replace all LSE128
	instructions with equivalent `.inst' directives.
	(HAVE_FEAT_LSE128): Remove all references.
	* configure: Regenerate.
	* configure.ac: Remove call to LIBAT_TEST_FEAT_AARCH64_LSE128.
 2024-06-12 10:23:38 +01:00
Victor Do Nascimento
5ad64d76c0 libatomic: Enable LSE128 128-bit atomics for Armv9.4-a 
The armv9.4-a architectural revision adds three new atomic operations
associated with the LSE128 feature:

  * LDCLRP - Atomic AND NOT (bitclear) of a location with 128-bit
  value held in a pair of registers, with original data loaded into
  the same 2 registers.
  * LDSETP - Atomic OR (bitset) of a location with 128-bit value held
  in a pair of registers, with original data loaded into the same 2
  registers.
  * SWPP - Atomic swap of one 128-bit value with 128-bit value held
  in a pair of registers.

It is worth noting that in keeping with existing 128-bit atomic
operations in `atomic_16.S', we have chosen to merge certain
less-restrictive orderings into more restrictive ones.  This is done
to minimize the number of branches in the atomic functions, minimizing
both the likelihood of branch mispredictions and, in keeping code
small, limit the need for extra fetch cycles.

Past benchmarking has revealed that acquire is typically slightly
faster than release (5-10%), such that for the most frequently used
atomics (CAS and SWP) it makes sense to add support for acquire, as
well as release.

Likewise, it was identified that combining acquire and release typically
results in little to no penalty, such that it is of negligible benefit
to distinguish between release and acquire-release, making the
combining release/acq_rel/seq_cst a worthwhile design choice.

This patch adds the logic required to make use of these when the
architectural feature is present and a suitable assembler available.

In order to do this, the following changes are made:

  1. Add a configure-time check to check for LSE128 support in the
  assembler.
  2. Edit host-config.h so that when N == 16, nifunc = 2.
  3. Where available due to LSE128, implement the second ifunc, making
  use of the novel instructions.
  4. For atomic functions unable to make use of these new
  instructions, define a new alias which causes the _i1 function
  variant to point ahead to the corresponding _i2 implementation.

libatomic/ChangeLog:

	* Makefile.am (AM_CPPFLAGS): add conditional setting of
	-DHAVE_FEAT_LSE128.
	* acinclude.m4 (LIBAT_TEST_FEAT_AARCH64_LSE128): New.
	* config/linux/aarch64/atomic_16.S (LSE128): New macro
	definition.
	(libat_exchange_16): New LSE128 variant.
	(libat_fetch_or_16): Likewise.
	(libat_or_fetch_16): Likewise.
	(libat_fetch_and_16): Likewise.
	(libat_and_fetch_16): Likewise.
	* config/linux/aarch64/host-config.h (IFUNC_COND_2): New.
	(IFUNC_NCOND): Add operand size checking.
	(has_lse2): Renamed from `ifunc1`.
	(has_lse128): New.
	(HWCAP2_LSE128): Likewise.
	* configure.ac: Add call to
	LIBAT_TEST_FEAT_AARCH64_LSE128.
	* configure (ac_subst_vars): Regenerated via autoreconf.
	* Makefile.in: Likewise.
	* auto-config.h.in: Likewise.
 2024-01-28 20:02:01 +00:00
Steve Ellcey
141abc6f1e Makefile.am (ARCH_AARCH64_LINUX): Add IFUNC_OPTIONS and libatomic_la_LIBADD. 
2017-12-04  Steve Ellcey  <sellcey@cavium.com>

	* Makefile.am (ARCH_AARCH64_LINUX): Add IFUNC_OPTIONS and
	libatomic_la_LIBADD.
	* config/linux/aarch64/host-config.h: New file.
	* configure.ac (IFUNC_RESOLVER_ARGS): Define.
	(ARCH_AARCH64_LINUX): New conditional for IFUNC builds.
	* configure.tgt (aarch64): Set ARCH and try_ifunc.
	(aarch64*-*-linux*) Update config_path.
	(aarch64*-*-linux*) Set IFUNC_RESOLVER_ARGS.
	* libatomic_i.h (GEN_SELECTOR): Add IFUNC_RESOLVER_ARGS argument.
	* Makefile.in: Regenerate.
	* auto-config.h.in: Regenerate.
	* configure: Regenerate.

From-SVN: r255399
 2017-12-05 00:49:09 +00:00
Torvald Riegel
969a32ce93 Fix __atomic to not implement atomic loads with CAS. 
gcc/
	* builtins.c (fold_builtin_atomic_always_lock_free): Make "lock-free"
	conditional on existance of a fast atomic load.
	* optabs-query.c (can_atomic_load_p): New function.
	* optabs-query.h (can_atomic_load_p): Declare it.
	* optabs.c (expand_atomic_exchange): Always delegate to libatomic if
	no fast atomic load is available for the particular size of access.
	(expand_atomic_compare_and_swap): Likewise.
	(expand_atomic_load): Likewise.
	(expand_atomic_store): Likewise.
	(expand_atomic_fetch_op): Likewise.
	* testsuite/lib/target-supports.exp
	(check_effective_target_sync_int_128): Remove x86 because it provides
	no fast atomic load.
	(check_effective_target_sync_int_128_runtime): Likewise.

libatomic/
	* acinclude.m4: Add #define FAST_ATOMIC_LDST_*.
	* auto-config.h.in: Regenerate.
	* config/x86/host-config.h (FAST_ATOMIC_LDST_16): Define to 0.
	(atomic_compare_exchange_n): New.
	* glfree.c (EXACT, LARGER): Change condition and add comments.

From-SVN: r245098
 2017-02-01 17:21:59 +00:00
Joseph Myers
267bac1078 tree-core.h (enum cv_qualifier): Add TYPE_QUAL_ATOMIC. 
gcc:
2013-11-05  Andrew MacLeod  <amacleod@redhat.com>
	    Joseph Myers  <joseph@codesourcery.com>

	* tree-core.h (enum cv_qualifier): Add TYPE_QUAL_ATOMIC.
	(enum tree_index): Add TI_ATOMICQI_TYPE, TI_ATOMICHI_TYPE,
	TI_ATOMICSI_TYPE, TI_ATOMICDI_TYPE and TI_ATOMICTI_TYPE.
	(struct tree_base): Add atomic_flag field.
	* tree.h (TYPE_ATOMIC): New accessor macro.
	(TYPE_QUALS, TYPE_QUALS_NO_ADDR_SPACE): Add TYPE_QUAL_ATOMIC.
	(TYPE_QUALS_NO_ADDR_SPACE_NO_ATOMIC): New macro.
	(atomicQI_type_node, atomicHI_type_node, atomicSI_type_node)
	(atomicDI_type_node, atomicTI_type_node): New macros for type
	nodes.
	* tree.c (set_type_quals): Set TYPE_ATOMIC.
	(find_atomic_core_type): New function.
	(build_qualified_type): Adjust alignment for qualified types.
	(build_atomic_base): New function
	(build_common_tree_nodes): Build atomicQI_type_node,
	atomicHI_type_node, atomicSI_type_node, atomicDI_type_node and
	atomicTI_type_node.
	* print-tree.c (print_node): Print atomic qualifier.
	* tree-pretty-print.c (dump_generic_node): Print atomic type
	attribute.
	* target.def (atomic_assign_expand_fenv): New hook.
	* doc/tm.texi.in (TARGET_ATOMIC_ASSIGN_EXPAND_FENV): New @hook.
	* doc/tm.texi: Regenerate.
	* targhooks.c (default_atomic_assign_expand_fenv): New function.
	* targhooks.h (default_atomic_assign_expand_fenv): Declare.
	* sync-builtins.def (__atomic_feraiseexcept): New built-in
	function.
	* config/i386/i386-builtin-types.def (VOID_FTYPE_PUSHORT): New
	function type.
	* config/i386/i386.c (enum ix86_builtins): Add
	IX86_BUILTIN_FNSTENV, IX86_BUILTIN_FLDENV, IX86_BUILTIN_FNSTSW and
	IX86_BUILTIN_FNCLEX.
	(bdesc_special_args): Add __builtin_ia32_fnstenv,
	__builtin_ia32_fldenv, __builtin_ia32_fnstsw and
	__builtin_ia32_fnclex.
	(ix86_expand_builtin): Handle the new built-in functions.
	(ix86_atomic_assign_expand_fenv): New function.
	(TARGET_ATOMIC_ASSIGN_EXPAND_FENV): New macro.
	* config/i386/i386.md (UNSPECV_FNSTENV, UNSPECV_FLDENV)
	(UNSPECV_FNSTSW, UNSPECV_FNCLEX): New unspecs.
	(fnstenv, fldenv, fnstsw, fnclex): New insns.

gcc/c-family:
2013-11-05  Andrew MacLeod  <amacleod@redhat.com>
	    Joseph Myers  <joseph@codesourcery.com>

	* c-common.h (enum rid): Add RID_ATOMIC.
	* c-common.c (c_common_reswords): Add _Atomic.
	(sync_resolve_params): Use TYPE_MAIN_VARIANT on pointer argument.
	(keyword_is_type_qualifier): Accept RID_ATOMIC.
	* c-format.c (check_format_types): Check for extra _Atomic
	qualifiers in format argument.
	* c-pretty-print.c (pp_c_cv_qualifiers): Handle atomic qualifier.
	(pp_c_type_qualifier_list): Mention _Atomic in comment.

gcc/c:
2013-11-05  Joseph Myers  <joseph@codesourcery.com>
	    Andrew MacLeod  <amacleod@redhat.com>

	* c-aux-info.c (gen_type): Handle atomic qualifier.
	* c-decl.c (validate_proto_after_old_defn): Do not remove atomic
	qualifiers when compating types.
	(shadow_tag_warned): Handle atomic_p in declspecs.
	(quals_from_declspecs): Likewise.
	(start_decl): Use c_type_promotes_to when promoting argument
	types.
	(grokdeclarator): Handle _Atomic.
	(get_parm_info): Diagnose any qualifier on "void" as only
	parameter.
	(store_parm_decls_oldstyle): Do not remove atomic qualifiers when
	comparing types.  Use c_type_promotes_to when promoting argument
	types.
	(finish_function): Use c_type_promotes_to when promoting argument
	types.
	(build_null_declspecs): Handle atomic_p in declspecs.
	(declspecs_add_qual): Handle RID_ATOMIC.
	* c-parser.c (c_token_starts_typename, c_token_is_qualifier)
	(c_token_starts_declspecs): Handle RID_ATOMIC.
	(c_parser_declspecs): Handle atomic type specifiers and
	qualifiers.
	(c_parser_typeof_specifier): Remove const and _Atomic qualifiers
	from types of expressions with atomic type.
	(c_parser_direct_declarator_inner): Use convert_lvalue_to_rvalue.
	(c_parser_attribute_any_word): Handle RID_ATOMIC.
	(c_parser_initializer, c_parser_initelt, c_parser_initval)
	(c_parser_statement_after_labels, c_parser_switch_statement)
	(c_parser_for_statement, c_parser_expr_no_commas)
	(c_parser_conditional_expression, c_parser_binary_expression)
	(c_parser_cast_expression, c_parser_unary_expression)
	(c_parser_postfix_expression)
	(c_parser_postfix_expression_after_primary, c_parser_expression):
	Use convert_lvalue_to_rvalue.
	(c_parser_expression_conv, c_parser_expr_list): Document
	conversion of lvalues to rvalues.  Use convert_lvalue_to_rvalue.
	(c_parser_objc_synchronized_statement): Use
	convert_lvalue_to_rvalue.
	(c_parser_objc_selector): Handle RID_ATOMIC.
	(c_parser_objc_receiver, c_parser_array_notation): Use
	convert_lvalue_to_rvalue.
	* c-tree.h (ctsk_typeof): Adjust comment to mention use for
	_Atomic (type-name).
	(struct c_declspecs): Add atomic_p field.
	(convert_lvalue_to_rvalue): Declare.
	* c-typeck.c (c_type_promotes_to): Promote atomic types to
	corresponding atomic types.
	(qualify_type): Don't add _Atomic qualifiers from second argument.
	(comp_target_types): Do not allow _Atomic mismatches.
	(type_lists_compatible_p): Do not remove atomic qualifiers when
	comparing types.
	(really_atomic_lvalue, convert_lvalue_to_rvalue)
	(build_atomic_assign): New functions.
	(build_unary_op): Use build_atomic_assign for atomic increment and
	decrement.
	(build_conditional_expr): Do not treat _Atomic void as a qualified
	version of void.
	(build_modify_expr): Use build_atomic_assign for atomic LHS.
	(find_anonymous_field_with_type, convert_to_anonymous_field)
	(convert_for_assignment): Do not remove atomic qualifiers when
	comparing types.
	(digest_init): Do not accept initialization of arrays of atomic
	elements by string constants.
	(build_asm_expr): Use convert_lvalue_to_rvalue.
	(build_binary_op): Do not treat _Atomic void as a qualified
	version of void.

gcc/objc:
2013-11-05  Andrew MacLeod  <amacleod@redhat.com>

	* objc-act.c (objc_push_parm): Handle atomic qualifier.

gcc/testsuite:
2013-11-05  Joseph Myers  <joseph@codesourcery.com>

	* lib/target-supports.exp
	(check_effective_target_fenv_exceptions): New function.
	* lib/atomic-dg.exp, gcc.dg/atomic/atomic.exp: New files.
	* gcc.dg/atomic/c11-atomic-exec-1.c,
	gcc.dg/atomic/c11-atomic-exec-2.c,
	gcc.dg/atomic/c11-atomic-exec-3.c,
	gcc.dg/atomic/c11-atomic-exec-4.c,
	gcc.dg/atomic/c11-atomic-exec-5.c, gcc.dg/c11-atomic-1.c,
	gcc.dg/c11-atomic-2.c, gcc.dg/c11-atomic-3.c,
	gcc.dg/c90-atomic-1.c, gcc.dg/c99-atomic-1.c: New tests.

libatomic:
2013-11-05  Joseph Myers  <joseph@codesourcery.com>

	* fenv.c: New file.
	* libatomic.map (LIBATOMIC_1.1): New symbol version.  Include
	__atomic_feraiseexcept.
	* configure.ac (libtool_VERSION): Change to 2:0:1.
	(fenv.h): Test for header.
	* Makefile.am (libatomic_la_SOURCES): Add fenv.c.
	* Makefile.in, auto-config.h.in, configure: Regenerate.

From-SVN: r204544
 2013-11-07 21:15:25 +00:00
Richard Henderson
483104922a Add libatomic as a target library. 
From-SVN: r187018
 2012-05-01 08:48:28 -07:00