The recent patch to convert all thumb1 code in libgcc to unified syntax
ommitted the conditional code that is used only when building the library
for minimal size. This patch fixes this case.
I've also fixed the COND macro so that a single definition is always used
that is for unified syntax. This eliminates a warning that is now being
seen from the assembler when compiling the ieee fp support code.
PR target/94220
* config/arm/lib1funcs.asm (COND): Use a single definition for
unified syntax.
(aeabi_uidivmod): Unified syntax when optimizing Thumb for size.
(aeabi_idivmod): Likewise.
(divsi3_skip_div0_test): Likewise.
Unified syntax has been the official syntax for thumb1 assembly for
over 10 years now. It's time we made preparations for that becoming
the default in the assembler. But before we can start doing that we
really need to clean up some laggards from the olden days. Libgcc
support for thumb1 is one such example.
This patch converts all of the legacy (disjoint) syntax that I could
find over to unified code. The identification was done by using a
trick version of gas that defaulted to unified mode which then faults
if legacy syntax is encountered. The code produced was then compared
against the old code to check for differences. One such difference
does exist, but that is because in unified syntax 'movs rd, rn' is
encoded as 'lsls rd, rn, #0', rather than 'adds rd, rn, #0'; but that
is a deliberate change that was introduced because the lsls encoding
more closely reflects the behaviour of 'movs' in arm state (where only
some of the condition flags are modified).
* config/arm/bpabi-v6m.S (aeabi_lcmp): Convert thumb1 code to unified
syntax.
(aeabi_ulcmp, aeabi_ldivmod, aeabi_uldivmod): Likewise.
(aeabi_frsub, aeabi_cfcmpeq, aeabi_fcmpeq): Likewise.
(aeabi_fcmp, aeabi_drsub, aeabi_cdrcmple): Likewise.
(aeabi_cdcmpeq, aeabi_dcmpeq, aeabi_dcmp): Likewise.
* config/arm/lib1funcs.S (Lend_fde): Convert thumb1 code to unified
syntax.
(divsi3, modsi3): Likewise.
(clzdi2, ctzsi2): Likewise.
* config/arm/libunwind.S (restore_core_regs): Convert thumb1 code to
unified syntax.
(UNWIND_WRAPPER): Likewise.
Softfloat single precision and double precision floating-point
multiplication routines in libgcc share some code with the
floating-point division of their corresponding precision. As the code
is structured now, this leads to *all* division code being pulled in an
executable in softfloat mode even if only multiplication is
performed.
This patch create some new LIB1ASMFUNCS macros to also build files with
just the multiplication and shared code as weak symbols. By putting
these earlier in the static library, they can then be picked up when
only multiplication is used and they are overriden by the global
definition in the existing file containing both multiplication and
division code when division is needed.
The patch also removes changes made to the FUNC_START and ARM_FUNC_START
macros in r218124 since the intent was to put multiplication and
division code into their own section in a later patch to achieve the
same size optimization. That approach relied on specific section layout
to ensure multiplication and division were not too far from the shared
bit of code in order to the branches to be within range. Due to lack of
guarantee regarding section layout, in particular with all the
possibility of linker scripts, this approach was chosen instead. This
patch keeps the two testcases that were posted by Tony Wang on the mailing
list to implement this approach and adds a new one.
2018-12-19 Thomas Preud'homme <thomas.preudhomme@linaro.org>
libgcc/
* /config/arm/lib1funcs.S (FUNC_START): Remove unused sp_section
parameter and corresponding code.
(ARM_FUNC_START): Likewise in both definitions.
Also update footer comment about condition that need to match with
gcc/config/arm/elf.h to also include libgcc/config/arm/t-arm.
* config/arm/ieee754-df.S (muldf3): Also build it if L_arm_muldf3 is
defined. Weakly define it in this case.
* config/arm/ieee754-sf.S (mulsf3): Likewise with L_arm_mulsf3.
* config/arm/t-elf (LIB1ASMFUNCS): Build _arm_muldf3.o and
_arm_mulsf3.o before muldiv versions if targeting Thumb-1 only. Add
comment to keep condition in sync with the one in
libgcc/config/arm/lib1funcs.S and gcc/config/arm/elf.h.
gcc/
* config/arm/elf.h: Update comment about condition that need to
match with libgcc/config/arm/lib1funcs.S to also include
libgcc/config/arm/t-arm.
* doc/sourcebuild.texi (output-exists, output-exists-not): Rename
subsubsection these directives are in to "Check for output files".
Move scan-symbol to that section and add to it new scan-symbol-not
directive.
2018-12-19 Tony Wang <tony.wang@arm.com>
Thomas Preud'homme <thomas.preudhomme@linaro.org>
gcc/testsuite/
* lib/lto.exp (lto-execute): Define output_file and testname_with_flags
to same value as execname.
(scan-symbol): Move and rename to ...
* lib/gcc-dg.exp (scan-symbol-common): This. Adapt into a
helper function returning true or false if a symbol is present.
(scan-symbol): New procedure.
(scan-symbol-not): Likewise.
* gcc.target/arm/size-optimization-ieee-1.c: New testcase.
* gcc.target/arm/size-optimization-ieee-2.c: Likewise.
* gcc.target/arm/size-optimization-ieee-3.c: Likewise.
From-SVN: r267282
The AArch32 instruction sets prior to Armv7 do not define the ISB and
DSB instructions that are needed to form a speculation barrier. While
I do not know of any instances of cores based on those instruction
sets being vulnerable to speculative side channel attacks it is
possible to run code built for those ISAs on more recent hardware
where they would become vulnerable.
This patch works around this by using a library call added to libgcc.
That code can then take any platform-specific actions necessary to
ensure safety.
For the moment I've only handled two cases: the library code being
built for armv7 or later anyway and running on Linux.
On Linux we can handle this by calling the kernel function that will
flush a small amount of cache. Such a sequence ends with a ISB+DSB
sequence if running on an Armv7 or later CPU.
gcc:
PR target/86951
* config/arm/arm-protos.h (arm_emit_speculation_barrier): New
prototype.
* config/arm/arm.c (speculation_barrier_libfunc): New static
variable.
(arm_init_libfuncs): Initialize it.
(arm_emit_speculation_barrier): New function.
* config/arm/arm.md (speculation_barrier): Call
arm_emit_speculation_barrier for architectures that do not have
DSB or ISB.
(speculation_barrier_insn): Only match on Armv7 or later.
libgcc:
PR target/86951
* config/arm/lib1funcs.asm (speculation_barrier): New function.
* config/arm/t-arm (LIB1ASMFUNCS): Add it to list of functions
to build.
From-SVN: r263806
2016-07-11 Hale Wang <hale.wang@arm.com>
Andre Vieira <andre.simoesdiasvieira@arm.com>
* config/arm/lib1funcs.S: Add new wrapper.
Co-Authored-By: Andre Vieira <andre.simoesdiasvieira@arm.com>
From-SVN: r238215
2016-07-07 Thomas Preud'homme <thomas.preudhomme@arm.com>
gcc/
* config/arm/arm-arches.def (armv8-m.base): Define new architecture.
(armv8-m.main): Likewise.
(armv8-m.main+dsp): Likewise.
* config/arm/arm-protos.h (FL_FOR_ARCH8M_BASE): Define.
(FL_FOR_ARCH8M_MAIN): Likewise.
* config/arm/arm-tables.opt: Regenerate.
* config/arm/bpabi.h: Add armv8-m.base, armv8-m.main and
armv8-m.main+dsp to BE8_LINK_SPEC.
* config/arm/arm.h (TARGET_HAVE_LDACQ): Exclude ARMv8-M.
(enum base_architecture): Add BASE_ARCH_8M_BASE and BASE_ARCH_8M_MAIN.
* config/arm/arm.c (arm_arch_name): Increase size to work with ARMv8-M
Baseline and Mainline.
(arm_option_override_internal): Also disable arm_restrict_it when
!arm_arch_notm. Update comment for -munaligned-access to also cover
ARMv8-M Baseline.
(arm_file_start): Increase buffer size for printing architecture name.
* doc/invoke.texi: Document architectures armv8-m.base, armv8-m.main
and armv8-m.main+dsp.
(mno-unaligned-access): Clarify that this is disabled by default for
ARMv8-M Baseline architectures as well.
gcc/testsuite/
* lib/target-supports.exp: Generate add_options_for_arm_arch_FUNC and
check_effective_target_arm_arch_FUNC_multilib for ARMv8-M Baseline and
ARMv8-M Mainline architectures.
libgcc/
* config/arm/lib1funcs.S (__ARM_ARCH__): Define to 8 for ARMv8-M.
From-SVN: r238081
2016-07-07 Thomas Preud'homme <thomas.preudhomme@arm.com>
libgcc/
* config/arm/lib1funcs.S (HAVE_ARM_CLZ): Define for ARMv6* or later
and ARMv5t* rather than for a fixed list of architectures.
From-SVN: r238080
2016-07-07 Thomas Preud'homme <thomas.preudhomme@arm.com>
gcc/
* config/arm/elf.h: Use __ARM_ARCH_ISA_THUMB and __ARM_ARCH_ISA_ARM to
decide whether to prevent some libgcc routines being included for some
multilibs rather than __ARM_ARCH_6M__ and add comment to indicate the
link between this condition and the one in
libgcc/config/arm/lib1func.S.
gcc/testsuite/
* lib/target-supports.exp (check_effective_target_arm_cortex_m): Use
__ARM_ARCH_ISA_ARM to test for Cortex-M devices.
libgcc/
* config/arm/bpabi-v6m.S: Clarify what architectures is the
implementation suitable for.
* config/arm/lib1funcs.S (__prefer_thumb__): Define among other cases
for all Thumb-1 only targets.
(NOT_ISA_TARGET_32BIT): Define for Thumb-1 only targets.
(THUMB_LDIV0): Test for NOT_ISA_TARGET_32BIT rather than
__ARM_ARCH_6M__.
(EQUIV): Likewise.
(ARM_FUNC_ALIAS): Likewise.
(umodsi3): Add check to __ARM_ARCH_ISA_THUMB != 1 to guard the idiv
version.
(modsi3): Likewise.
(clzsi2): Test for NOT_ISA_TARGET_32BIT rather than __ARM_ARCH_6M__.
(clzdi2): Likewise.
(ctzsi2): Likewise.
(L_interwork_call_via_rX): Test for __ARM_ARCH_ISA_ARM rather than
__ARM_ARCH_6M__ in guard for checking whether it is defined.
(final includes): Test for NOT_ISA_TARGET_32BIT rather than
__ARM_ARCH_6M__ and add comment to indicate the connection between
this condition and the one in gcc/config/arm/elf.h.
* config/arm/libunwind.S: Test for __ARM_ARCH_ISA_THUMB and
__ARM_ARCH_ISA_ARM rather than __ARM_ARCH_6M__.
* config/arm/t-softfp: Likewise.
From-SVN: r238079
2014-11-27 Tony Wang <tony.wang@arm.com>
libgcc/
* config/arm/lib1funcs.S (FUNC_START): Add conditional section
redefine for macro L_arm_muldivsf3 and L_arm_muldivdf3.
(SYM_END, ARM_SYM_START): Add macros used to expose function Symbols.
From-SVN: r218124
