Thanks to Andreas Schwab for the pointer on how to fix this properly.
This re-enables -msave-restore for shared libraries, and uses the
t-slibgcc-libgcc file to get the save-restore routines included directly
in shared libraries so that we don't need to indirect through the PLT
to reach them, which doesn't work.
This was tested with 32-bit/elf and 64-bit/linux cross toolchain builds and
checks, with a patch to force -msave-restore on if not specified on the
command line. There are no g++ or gfortran regressions. There are 4 gcc
regressions, but 3 are sibling call tests that can't work with the
save-restore routines, and the other is non-obvious, but for a feature
we haven't been testing I think this is pretty good. Before these patches,
there were thousands of regressions when I turned -msave-restore on.
I didn't test freebsd as I don't have any easy way to test it, but its
libgcc config is identical to linux except for the linux specific unwinder
file, so I don't expect problems.
Committed.
Jim
gcc/
* config/riscv/riscv.c (riscv_option_override): Revert 2019-08-30
change.
libgcc/
* config.host (riscv*-*-linux*): Add t-slibgcc-libgcc to tmake_file.
(riscv*-*-freebsd*): Likewise.
---
gcc/config/riscv/riscv.c | 10 ----------
libgcc/config.host | 4 ++--
2 files changed, 2 insertions(+), 12 deletions(-)
diff --git a/gcc/config/riscv/riscv.c b/gcc/config/riscv/riscv.c
index 1e7528f1cb9..9b16a1eb9c2 100644
--- a/gcc/config/riscv/riscv.c
+++ b/gcc/config/riscv/riscv.c
@@ -4636,16 +4636,6 @@ riscv_option_override (void)
error ("%<-mriscv-attribute%> RISC-V ELF attribute requires GNU as 2.32"
" [%<-mriscv-attribute%>]");
#endif
-
- /* The save-restore routines use t0 which is clobbered by the plt header,
- so we can't use them when building shared libraries. */
- if (TARGET_SAVE_RESTORE && flag_pic && TARGET_PLT)
- {
- target_flags &= ~MASK_SAVE_RESTORE;
- if (target_flags_explicit & MASK_SAVE_RESTORE)
- warning (0, "%<-msave-restore%> disabled; not supported with PLT "
- "based shared libraries");
- }
}
/* Implement TARGET_CONDITIONAL_REGISTER_USAGE. */
diff --git a/libgcc/config.host b/libgcc/config.host
index a3976702ab5..1db52878a5e 100644
--- a/libgcc/config.host
+++ b/libgcc/config.host
@@ -1201,12 +1201,12 @@ pru-*-*)
tm_file="$tm_file pru/pru-abi.h"
;;
riscv*-*-linux*)
- tmake_file="${tmake_file} riscv/t-softfp${host_address} t-softfp
riscv/t-elf riscv/t-elf${host_address}"
+ tmake_file="${tmake_file} riscv/t-softfp${host_address} t-softfp
riscv/t-elf riscv/t-elf${host_address} t-slibgcc-libgcc"
extra_parts="$extra_parts crtbegin.o crtend.o crti.o crtn.o crtendS.o
crtbeginT.o"
md_unwind_header=riscv/linux-unwind.h
;;
riscv*-*-freebsd*)
- tmake_file="${tmake_file} riscv/t-softfp${host_address} t-softfp
riscv/t-elf riscv/t-elf${host_address}"
+ tmake_file="${tmake_file} riscv/t-softfp${host_address} t-softfp
riscv/t-elf riscv/t-elf${host_address} t-slibgcc-libgcc"
extra_parts="$extra_parts crtbegin.o crtend.o crti.o crtn.o crtendS.o
crtbeginT.o"
;;
riscv*-*-*)
--
2.17.1
