Wilco Dijkstra <wilco.dijks...@arm.com> writes:
> Fix libatomic build to support --disable-gnu-indirect-function on AArch64.
> Always build atomic_16.S and add aliases to the __atomic_* functions if
> !HAVE_IFUNC.
This description is too brief for me. Could you say in detail how the
new scheme works? E.g. the description doesn't explain:
> -if ARCH_AARCH64_HAVE_LSE128
> -AM_CPPFLAGS = -DHAVE_FEAT_LSE128
> -endif
And what's the purpose of ARCH_AARCH64_HAVE_LSE128 after this change?
Is the indirection via ALIAS2 necessary? Couldn't ENTRY just define
the __atomic_* symbols directly, as non-hidden, if we remove the
libat_ prefix? That would make it easier to ensure that the lists
are kept up-to-date.
Shouldn't we skip the ENTRY_FEAT functions and existing aliases
if !HAVE_IFUNC?
I think it'd be worth (as a prepatch) splitting the file into two
#included subfiles, one that contains the base AArch64 routines and one
that contains the optimised versions. The former would then be #included
for all builds while the latter would be specific to HAVE_IFUNC.
Thanks,
Richard
> Passes regress and bootstrap, OK for commit?
>
> libatomic:
> PR target/113986
> * Makefile.in: Regenerated.
> * Makefile.am: Make atomic_16.S not depend on HAVE_IFUNC.
> Remove predefine of HAVE_FEAT_LSE128.
> * config/linux/aarch64/atomic_16.S: Add __atomic_ aliases if
> !HAVE_IFUNC.
> * config/linux/aarch64/host-config.h: Correctly handle !HAVE_IFUNC.
>
> ---
>
> diff --git a/libatomic/Makefile.am b/libatomic/Makefile.am
> index
> d49c44c7d5fbe83061fddd1f8ef4813a39eb1b8b..980677f353345c050f6cef2d57090360216c56cf
> 100644
> --- a/libatomic/Makefile.am
> +++ b/libatomic/Makefile.am
> @@ -130,12 +130,8 @@ libatomic_la_LIBADD = $(foreach s,$(SIZES),$(addsuffix
> _$(s)_.lo,$(SIZEOBJS)))
> ## On a target-specific basis, include alternates to be selected by IFUNC.
> if HAVE_IFUNC
> if ARCH_AARCH64_LINUX
> -if ARCH_AARCH64_HAVE_LSE128
> -AM_CPPFLAGS = -DHAVE_FEAT_LSE128
> -endif
> IFUNC_OPTIONS = -march=armv8-a+lse
> libatomic_la_LIBADD += $(foreach s,$(SIZES),$(addsuffix
> _$(s)_1_.lo,$(SIZEOBJS)))
> -libatomic_la_SOURCES += atomic_16.S
>
> endif
> if ARCH_ARM_LINUX
> @@ -155,6 +151,10 @@ libatomic_la_LIBADD += $(addsuffix
> _16_1_.lo,$(SIZEOBJS)) \
> endif
> endif
>
> +if ARCH_AARCH64_LINUX
> +libatomic_la_SOURCES += atomic_16.S
> +endif
> +
> libatomic_convenience_la_SOURCES = $(libatomic_la_SOURCES)
> libatomic_convenience_la_LIBADD = $(libatomic_la_LIBADD)
>
> diff --git a/libatomic/Makefile.in b/libatomic/Makefile.in
> index
> 11c8ec7ba15ba7da5ef55e90bd836317bc270061..d9d529bc502d4ce7b9997640d5f40f5d5cc1232c
> 100644
> --- a/libatomic/Makefile.in
> +++ b/libatomic/Makefile.in
> @@ -90,17 +90,17 @@ build_triplet = @build@
> host_triplet = @host@
> target_triplet = @target@
> @ARCH_AARCH64_LINUX_TRUE@@HAVE_IFUNC_TRUE@am__append_1 = $(foreach
> s,$(SIZES),$(addsuffix _$(s)_1_.lo,$(SIZEOBJS)))
> -@ARCH_AARCH64_LINUX_TRUE@@HAVE_IFUNC_TRUE@am__append_2 = atomic_16.S
> -@ARCH_ARM_LINUX_TRUE@@HAVE_IFUNC_TRUE@am__append_3 = $(foreach \
> +@ARCH_ARM_LINUX_TRUE@@HAVE_IFUNC_TRUE@am__append_2 = $(foreach \
> @ARCH_ARM_LINUX_TRUE@@HAVE_IFUNC_TRUE@ s,$(SIZES),$(addsuffix \
> @ARCH_ARM_LINUX_TRUE@@HAVE_IFUNC_TRUE@ _$(s)_1_.lo,$(SIZEOBJS))) \
> @ARCH_ARM_LINUX_TRUE@@HAVE_IFUNC_TRUE@ $(addsuffix \
> @ARCH_ARM_LINUX_TRUE@@HAVE_IFUNC_TRUE@ _8_2_.lo,$(SIZEOBJS)) \
> @ARCH_ARM_LINUX_TRUE@@HAVE_IFUNC_TRUE@ tas_1_2_.lo
> -@ARCH_I386_TRUE@@HAVE_IFUNC_TRUE@am__append_4 = $(addsuffix
> _8_1_.lo,$(SIZEOBJS))
> -@ARCH_X86_64_TRUE@@HAVE_IFUNC_TRUE@am__append_5 = $(addsuffix
> _16_1_.lo,$(SIZEOBJS)) \
> +@ARCH_I386_TRUE@@HAVE_IFUNC_TRUE@am__append_3 = $(addsuffix
> _8_1_.lo,$(SIZEOBJS))
> +@ARCH_X86_64_TRUE@@HAVE_IFUNC_TRUE@am__append_4 = $(addsuffix
> _16_1_.lo,$(SIZEOBJS)) \
> @ARCH_X86_64_TRUE@@HAVE_IFUNC_TRUE@ $(addsuffix
> _16_2_.lo,$(SIZEOBJS))
>
> +@ARCH_AARCH64_LINUX_TRUE@am__append_5 = atomic_16.S
> subdir = .
> ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
> am__aclocal_m4_deps = $(top_srcdir)/../config/acx.m4 \
> @@ -156,8 +156,7 @@ am__uninstall_files_from_dir = { \
> }
> am__installdirs = "$(DESTDIR)$(toolexeclibdir)"
> LTLIBRARIES = $(noinst_LTLIBRARIES) $(toolexeclib_LTLIBRARIES)
> -@ARCH_AARCH64_LINUX_TRUE@@HAVE_IFUNC_TRUE@am__objects_1 = \
> -@ARCH_AARCH64_LINUX_TRUE@@HAVE_IFUNC_TRUE@ atomic_16.lo
> +@ARCH_AARCH64_LINUX_TRUE@am__objects_1 = atomic_16.lo
> am_libatomic_la_OBJECTS = gload.lo gstore.lo gcas.lo gexch.lo \
> glfree.lo lock.lo init.lo fenv.lo fence.lo flag.lo \
> $(am__objects_1)
> @@ -425,7 +424,7 @@ libatomic_la_LDFLAGS = $(libatomic_version_info)
> $(libatomic_version_script) \
> $(lt_host_flags) $(libatomic_darwin_rpath)
>
> libatomic_la_SOURCES = gload.c gstore.c gcas.c gexch.c glfree.c lock.c \
> - init.c fenv.c fence.c flag.c $(am__append_2)
> + init.c fenv.c fence.c flag.c $(am__append_5)
> SIZEOBJS = load store cas exch fadd fsub fand fior fxor fnand tas
> EXTRA_libatomic_la_SOURCES = $(addsuffix _n.c,$(SIZEOBJS))
> libatomic_la_DEPENDENCIES = $(libatomic_la_LIBADD) $(libatomic_version_dep)
> @@ -451,9 +450,8 @@ all_c_files := $(foreach dir,$(search_path),$(wildcard
> $(dir)/*.c))
> # Then sort through them to find the one we want, and select the first.
> M_SRC = $(firstword $(filter %/$(M_FILE), $(all_c_files)))
> libatomic_la_LIBADD = $(foreach s,$(SIZES),$(addsuffix \
> - _$(s)_.lo,$(SIZEOBJS))) $(am__append_1) $(am__append_3) \
> - $(am__append_4) $(am__append_5)
> -@ARCH_AARCH64_HAVE_LSE128_TRUE@@ARCH_AARCH64_LINUX_TRUE@@HAVE_IFUNC_TRUE@AM_CPPFLAGS
> = -DHAVE_FEAT_LSE128
> + _$(s)_.lo,$(SIZEOBJS))) $(am__append_1) $(am__append_2) \
> + $(am__append_3) $(am__append_4)
> @ARCH_AARCH64_LINUX_TRUE@@HAVE_IFUNC_TRUE@IFUNC_OPTIONS = -march=armv8-a+lse
> @ARCH_ARM_LINUX_TRUE@@HAVE_IFUNC_TRUE@IFUNC_OPTIONS = -march=armv7-a+fp
> -DHAVE_KERNEL64
> @ARCH_I386_TRUE@@HAVE_IFUNC_TRUE@IFUNC_OPTIONS = -march=i586
> diff --git a/libatomic/config/linux/aarch64/atomic_16.S
> b/libatomic/config/linux/aarch64/atomic_16.S
> index
> d4a360a6f7812351249d0a0ad7f60373b7f8c35a..772f84c0a24dab52773e25d053f5006fa8f28560
> 100644
> --- a/libatomic/config/linux/aarch64/atomic_16.S
> +++ b/libatomic/config/linux/aarch64/atomic_16.S
> @@ -38,6 +38,8 @@
> The libat_<op>_16_i1 entry points are used when LSE128 is available.
> The libat_<op>_16_i2 entry points are used when LSE2 is available. */
>
> +#include "auto-config.h"
> +
> #if HAVE_FEAT_LSE128
> .arch armv9-a+lse128
> #else
> @@ -67,8 +69,8 @@ NAME: \
> .cfi_endproc; \
> .size NAME, .-NAME;
>
> -#define ALIAS(NAME, FROM, TO) \
> - ALIAS1 (FROM (NAME),TO (NAME))
> +#define ALIAS(NAME, FROM, TO) ALIAS1 (FROM (NAME),TO (NAME))
> +#define ALIAS2(NAME) ALIAS1 (__atomic_##NAME, libat_##NAME)
>
> #define ALIAS1(ALIAS, NAME) \
> .global ALIAS; \
> @@ -747,6 +749,28 @@ ALIAS (libat_fetch_nand_16, LSE2, CORE)
> ALIAS (libat_nand_fetch_16, LSE2, CORE)
> ALIAS (libat_test_and_set_16, LSE2, CORE)
>
> +/* Emit __atomic_* entrypoints if no ifuncs. */
> +
> +#if !HAVE_IFUNC
> +ALIAS2 (load_16)
> +ALIAS2 (store_16)
> +ALIAS2 (compare_exchange_16)
> +ALIAS2 (exchange_16)
> +ALIAS2 (fetch_add_16)
> +ALIAS2 (add_fetch_16)
> +ALIAS2 (fetch_sub_16)
> +ALIAS2 (sub_fetch_16)
> +ALIAS2 (fetch_or_16)
> +ALIAS2 (or_fetch_16)
> +ALIAS2 (fetch_and_16)
> +ALIAS2 (and_fetch_16)
> +ALIAS2 (fetch_xor_16)
> +ALIAS2 (xor_fetch_16)
> +ALIAS2 (fetch_nand_16)
> +ALIAS2 (nand_fetch_16)
> +ALIAS2 (test_and_set_16)
> +#endif
> +
> /* GNU_PROPERTY_AARCH64_* macros from elf.h for use in asm code. */
> #define FEATURE_1_AND 0xc0000000
> #define FEATURE_1_BTI 1
> diff --git a/libatomic/config/linux/aarch64/host-config.h
> b/libatomic/config/linux/aarch64/host-config.h
> index
> 4e3541240633dc26de4a57c506b7e4b0c50185c2..030b56ae4df97f1fd33f141c956d16d5eafb89e1
> 100644
> --- a/libatomic/config/linux/aarch64/host-config.h
> +++ b/libatomic/config/linux/aarch64/host-config.h
> @@ -24,6 +24,13 @@
> #if HAVE_IFUNC
> #include <sys/auxv.h>
>
> +#ifndef HWCAP_USCAT
> +# define HWCAP_USCAT (1 << 25)
> +#endif
> +#ifndef HWCAP2_LSE128
> +# define HWCAP2_LSE128 (1UL << 47)
> +#endif
> +
> #if __has_include(<sys/ifunc.h>)
> # include <sys/ifunc.h>
> #else
> @@ -35,7 +42,6 @@ typedef struct __ifunc_arg_t {
> # define _IFUNC_ARG_HWCAP (1ULL << 62)
> #endif
>
> -#ifdef HWCAP_USCAT
> # if N == 16
> # define IFUNC_COND_1 (has_lse128 (hwcap, features))
> # define IFUNC_COND_2 (has_lse2 (hwcap, features))
> @@ -44,19 +50,6 @@ typedef struct __ifunc_arg_t {
> # define IFUNC_COND_1 (hwcap & HWCAP_ATOMICS)
> # define IFUNC_NCOND(N) 1
> # endif
> -#else
> -# define IFUNC_COND_1 (false)
> -# define IFUNC_NCOND(N) 1
> -#endif
> -
> -#endif /* HAVE_IFUNC */
> -
> -/* All 128-bit atomic functions are defined in aarch64/atomic_16.S. */
> -#if N == 16
> -# define DONE 1
> -#endif
> -
> -#ifdef HWCAP_USCAT
>
> #define MIDR_IMPLEMENTOR(midr) (((midr) >> 24) & 255)
> #define MIDR_PARTNUM(midr) (((midr) >> 4) & 0xfff)
> @@ -89,11 +82,6 @@ has_lse2 (unsigned long hwcap, const __ifunc_arg_t
> *features)
>
> #define AT_FEAT_FIELD(isar0) (((isar0) >> 20) & 15)
>
> -/* Ensure backwards compatibility with glibc <= 2.38. */
> -#ifndef HWCAP2_LSE128
> -#define HWCAP2_LSE128 (1UL << 47)
> -#endif
> -
> static inline bool
> has_lse128 (unsigned long hwcap, const __ifunc_arg_t *features)
> {
> @@ -116,6 +104,14 @@ has_lse128 (unsigned long hwcap, const __ifunc_arg_t
> *features)
> return false;
> }
>
> +#endif /* HAVE_IFUNC */
> +
> +/* All 128-bit atomic functions are defined in aarch64/atomic_16.S. */
> +#if N == 16
> +# define DONE 1
> +# if !HAVE_IFUNC
> +# define IFUNC_ALT 1
> +# endif
> #endif
>
> #include_next <host-config.h>
