Use `-fasynchronous-unwind-tables' rather than `-fexceptions
-fnon-call-exceptions' in LIB2_DIVMOD_FUNCS compilation flags so as to
provide unwind tables for the affected functions while not pulling the
unwinder proper, which is not required here.
Beyond saving program space it fixes a RISC-V glibc build error due to
unsatisfied `malloc' and `free' references from the unwinder causing
link errors with `ld.so' where libgcc has been built at -O0.
libgcc/
* config/riscv/t-elf (LIB2_DIVMOD_EXCEPTION_FLAGS): New
variable.
Rewrite code sequences throughout the 64-bit RISC-V `__riscv_save_*'
routines replacing `li t1, -48', `li t1, -64', and `li t1, -80',
instructions, which do not have a compressed encoding, respectively with
`li t1, 3', `li t1, 4', and `li t1, 4', which do, and then adjusting the
remaining code accordingly observing that `sub sp, sp, t1' takes the
same amount of space as an `slli t1, t1, 4'/`add sp, sp, t1' instruction
pair does, again due to the use of compressed encodings, saving 6 bytes
total.
This change does increase code size by 4 bytes for RISC-V processors
lacking the compressed instruction set, however their users couldn't
care about the code size or they would have chosen an implementation
that does have the compressed instructions, wouldn't they?
libgcc/
* config/riscv/save-restore.S [__riscv_xlen == 64]
(__riscv_save_10, __riscv_save_8, __riscv_save_6, __riscv_save_4)
(__riscv_save_2): Replace negative immediates used for the final
stack pointer adjustment with positive ones, right-shifted by 4.
The ISA manual specifies that divide by zero always returns -1 as the result.
We were failing to do that when the dividend was negative.
Original patch from Virginie Moser.
libgcc/
* config/riscv/div.S (__divdi3): For negative arguments, change bgez
to bgtz.
Using -mno-fdiv gives linker errors unless we build the missing divide
routines in libgcc always. There is at least one university project
designing RISC-V parts without FP divide that wants to use the option.
libgcc/
* config/riscv/t-softfp32 (softfp_extra): Add FP divide routines
From-SVN: r277723
Current glibc no longer gives the ucontext_t type the tag struct
ucontext, to conform with POSIX namespace rules. This requires
various linux-unwind.h files in libgcc, that were previously using
struct ucontext, to be fixed to use ucontext_t instead. This is
similar to the removal of the struct siginfo tag from siginfo_t some
years ago.
This patch changes those files to use ucontext_t instead. As the
standard name that should be unconditionally safe, so this is not
restricted to architectures supported by glibc, or conditioned on the
glibc version.
Tested compilation together with current glibc with glibc's
build-many-glibcs.py.
* config/aarch64/linux-unwind.h (aarch64_fallback_frame_state),
config/alpha/linux-unwind.h (alpha_fallback_frame_state),
config/bfin/linux-unwind.h (bfin_fallback_frame_state),
config/i386/linux-unwind.h (x86_64_fallback_frame_state,
x86_fallback_frame_state), config/m68k/linux-unwind.h (struct
uw_ucontext), config/nios2/linux-unwind.h (struct nios2_ucontext),
config/pa/linux-unwind.h (pa32_fallback_frame_state),
config/riscv/linux-unwind.h (riscv_fallback_frame_state),
config/sh/linux-unwind.h (sh_fallback_frame_state),
config/tilepro/linux-unwind.h (tile_fallback_frame_state),
config/xtensa/linux-unwind.h (xtensa_fallback_frame_state): Use
ucontext_t instead of struct ucontext.
From-SVN: r249731
