Hello,
using the -mcall-linux option on powerpc64le-linux (which should be a no-op)
currently causes the compiler driver to pass -mbig to the linker. Likewise,
using -mcall-aixdesc (which is allowed when also using -mabi=elfv1, like
certain versions of the Linux kernel do), causes the compiler driver to
pass -mbig to the linker.
While in both cases the incorrect effect can be worked around by using an
explicit -mlittle-endian, this should not be required in a compiler built
for the powerpc64le-linux target.
The reason for this behaviour is use of an ENDIAN_SELECT statement in
ASM_SPEC as defined in sysv4.h, and this ENDIAN_SELECT macro hard-codes
certain byte orders in response to various -mcall- options:
big-endian for -mcall-aixdesc, -mcall-{free,net,open}bsd and -mcall-linux;
little-endian for -mcall-i960-old.
Interestingly enough, for the big-endian cases above, this affects only
the *assembler*; the compiler itself will not switch endianness. However,
for -mcall-i960-old, there is code in SUBTARGET_OVERRIDE_OPTIONS to also
switch the compiler's byte order.
I'm not 100% sure what to do about -mcall-i960-old, but at least the
behaviour is self-consistent, so I left it alone for now.
However, -mcall-aixdesc, -mcall-linux (and possibly in the future
also -mcall-*bsd) should clearly not imply a particular byte order,
and don't work in a consistent manner on little-endian systems today
anyway, so the patch below removes this clause from ENDIAN_SELECT.
As a side-effect, I noticed that there apparently was some attempt
in the past to pass endian options to cc1, as evidenced by specs
substrings like %cc1_endian_default. However, the current set of
header files never defines any of those specs to any non-empty
value, so this patch removes all of them as well.
Tested on powerpc64-linux (-m64/-m32) and powerpc64le-linux.
OK for mainline?
Bye,
Ulrich
ChangeLog:
* config/rs6000/sysv4.h (ENDIAN_SELECT): Do not attempt to enforce
big-endian mode for -mcall-aixdesc, -mcall-freebsd, -mcall-netbsd,
-mcall-openbsd, or -mcall-linux.
(CC1_ENDIAN_BIG_SPEC): Remove.
(CC1_ENDIAN_LITTLE_SPEC): Remove.
(CC1_ENDIAN_DEFAULT_SPEC): Remove.
(CC1_SPEC): Remove (always empty) %cc1_endian_... spec.
(SUBTARGET_EXTRA_SPECS): Remove %cc1_endian_big, %cc1_endian_little,
and %cc1_endian_default.
* config/rs6000/sysv4le.h (CC1_ENDIAN_DEFAULT_SPEC): Remove.
Index: gcc/config/rs6000/sysv4le.h
===================================================================
--- gcc/config/rs6000/sysv4le.h (revision 207578)
+++ gcc/config/rs6000/sysv4le.h (working copy)
@@ -22,9 +22,6 @@
#undef TARGET_DEFAULT
#define TARGET_DEFAULT MASK_LITTLE_ENDIAN
-#undef CC1_ENDIAN_DEFAULT_SPEC
-#define CC1_ENDIAN_DEFAULT_SPEC "%(cc1_endian_little)"
-
#undef DEFAULT_ASM_ENDIAN
#define DEFAULT_ASM_ENDIAN " -mlittle"
Index: gcc/config/rs6000/sysv4.h
===================================================================
--- gcc/config/rs6000/sysv4.h (revision 207578)
+++ gcc/config/rs6000/sysv4.h (working copy)
@@ -522,8 +522,6 @@
#define ENDIAN_SELECT(BIG_OPT, LITTLE_OPT, DEFAULT_OPT) \
"%{mlittle|mlittle-endian:" LITTLE_OPT ";" \
"mbig|mbig-endian:" BIG_OPT ";" \
- "mcall-aixdesc|mcall-freebsd|mcall-netbsd|" \
- "mcall-openbsd|mcall-linux:" BIG_OPT ";" \
"mcall-i960-old:" LITTLE_OPT ";" \
":" DEFAULT_OPT "}"
@@ -536,20 +534,12 @@
%{memb|msdata=eabi: -memb}" \
ENDIAN_SELECT(" -mbig", " -mlittle", DEFAULT_ASM_ENDIAN)
-#define CC1_ENDIAN_BIG_SPEC ""
-
-#define CC1_ENDIAN_LITTLE_SPEC ""
-
-#define CC1_ENDIAN_DEFAULT_SPEC "%(cc1_endian_big)"
-
#ifndef CC1_SECURE_PLT_DEFAULT_SPEC
#define CC1_SECURE_PLT_DEFAULT_SPEC ""
#endif
-/* Pass -G xxx to the compiler and set correct endian mode. */
+/* Pass -G xxx to the compiler. */
#define CC1_SPEC "%{G*} %(cc1_cpu)" \
- ENDIAN_SELECT(" %(cc1_endian_big)", " %(cc1_endian_little)", \
- " %(cc1_endian_default)") \
"%{meabi: %{!mcall-*: -mcall-sysv }} \
%{!meabi: %{!mno-eabi: \
%{mrelocatable: -meabi } \
@@ -903,9 +893,6 @@
{ "link_os_netbsd", LINK_OS_NETBSD_SPEC }, \
{ "link_os_openbsd", LINK_OS_OPENBSD_SPEC }, \
{ "link_os_default", LINK_OS_DEFAULT_SPEC }, \
- { "cc1_endian_big", CC1_ENDIAN_BIG_SPEC }, \
- { "cc1_endian_little", CC1_ENDIAN_LITTLE_SPEC }, \
- { "cc1_endian_default", CC1_ENDIAN_DEFAULT_SPEC }, \
{ "cc1_secure_plt_default", CC1_SECURE_PLT_DEFAULT_SPEC }, \
{ "cpp_os_ads", CPP_OS_ADS_SPEC }, \
{ "cpp_os_yellowknife", CPP_OS_YELLOWKNIFE_SPEC }, \
--
Dr. Ulrich Weigand
GNU/Linux compilers and toolchain
ulrich.weig...@de.ibm.com
