[PATCH] Revert "[PATCH] RISC-V: Use new linker emulations for glibc ABI."

[Fangrui Song]

This reverts commit 37d57ac9a636f2235f9060e84fb8dd7968abd1dc.

The resolution to https://sourceware.org/bugzilla/show_bug.cgi?id=22962
let GCC pass -m emulation to ld and let the ld emulation configure
default library paths.  This scheme is problematic:

* It's not ld's business to specify default -L.  Different platforms have
different opinions on the hierarchy and all other arches work well without ld's
default -L.
* If some ABI derived library paths are desired, the compiler driver is in a
better position to make the decision and traditionally has done this.
* -m emulation is opaque to the compiler driver.  It doesn't affect -B, so
data files like crt*.o, libasan_preinit.o, and libtsan_preinit.o are not affected.

As is, many platforms just use symlinks to fake the lib64/{ilp32{,f},lp64{,f}}
hierarchies needed by the GNU ld emulation.  They can always specify -L
explicitly if they want some ABI derived library paths.  See also the rejected
https://reviews.llvm.org/D95755

gcc/Changelog:

    * config/riscv/linux.h (LD_EMUL_SUFFIX): Remove.
    (LINK_SPEC): Remove LD_EMUL_SUFFIX.
---
 gcc/config/riscv/linux.h | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/gcc/config/riscv/linux.h b/gcc/config/riscv/linux.h
index 38803723ba9..e0ff6e6a178 100644
--- a/gcc/config/riscv/linux.h
+++ b/gcc/config/riscv/linux.h
@@ -49,16 +49,8 @@ along with GCC; see the file COPYING3.  If not see
 
 #define CPP_SPEC "%{pthread:-D_REENTRANT}"
 
-#define LD_EMUL_SUFFIX \
-  "%{mabi=lp64d:}" \
-  "%{mabi=lp64f:_lp64f}" \
-  "%{mabi=lp64:_lp64}" \
-  "%{mabi=ilp32d:}" \
-  "%{mabi=ilp32f:_ilp32f}" \
-  "%{mabi=ilp32:_ilp32}"
-
 #define LINK_SPEC "\
--melf" XLEN_SPEC DEFAULT_ENDIAN_SPEC "riscv" LD_EMUL_SUFFIX " \
+-melf" XLEN_SPEC DEFAULT_ENDIAN_SPEC "riscv \
 %{mno-relax:--no-relax} \
 %{mbig-endian:-EB} \
 %{mlittle-endian:-EL} \
-- 
2.36.1.476.g0c4daa206d-goog