Andrei Borzenkov <arvidj...@gmail.com> writes:
> 24.08.2015 11:12, Andrei Borzenkov пишет:
>> Could you test attached patch for both gcc and clang? Use
>>
>> configure TARGET_CC=clang
>
> Sorry, was broken, fixed version attached.
Your patch works for me with gcc, although config.log shows this warning
when building the test program in your new code with the correct flags
for gcc (-mabi=32):
ld: warning: cannot find entry symbol __start; defaulting to 00000000004000d0
Here's the relevant excerpt:
--8<---------------cut here---------------start------------->8---
configure:24700: gcc -o conftest -Os -Wall -W -Wshadow -Wpointer-arith -Wundef
-Wchar-subscripts -Wcomment -Wdeprecated-declarations -Wdisabled-optimization
-Wdiv-by-zero -Wfloat-equal -Wformat-extra-args -Wformat-security -Wformat-y2k
-Wimplicit -Wimplicit-function-declaration -Wimplicit-int -Wmain
-Wmissing-braces -Wmissing-format-attribute -Wmultichar -Wparentheses
-Wreturn-type -Wsequence-point -Wshadow -Wsign-compare -Wswitch -Wtrigraphs
-Wunknown-pragmas -Wunused -Wunused-function -Wunused-label -Wunused-parameter
-Wunused-value -Wunused-variable -Wwrite-strings -Wnested-externs
-Wstrict-prototypes -g -Wredundant-decls -Wmissing-prototypes
-Wmissing-declarations -Wcast-align -Wextra -Wattributes -Wendif-labels
-Winit-self -Wint-to-pointer-cast -Winvalid-pch -Wmissing-field-initializers
-Wnonnull -Woverflow -Wvla -Wpointer-to-int-cast -Wstrict-aliasing
-Wvariadic-macros -Wvolatile-register-var -Wpointer-sign -Wmissing-include-dirs
-Wmissing-prototypes -Wmissing-declarations -Wformat=2 -mabi=32 -Werror -Wall
-W -DGRUB_CPU_MIPSEL=1 -DGRUB_MACHINE_MIPS_LOONGSON=1
-DGRUB_MACHINE=MIPS_LOONGSON -nostdlib -static conftest.c >&5
ld: warning: cannot find entry symbol __start; defaulting to 00000000004000d0
configure:24700: $? = 0
configure:24708: result: -mabi=32
--8<---------------cut here---------------end--------------->8---
I also worry that linking an O32 executable might be fragile on a pure
non-multilib N32 system such as GNU Guix, where we lack even the gcc
runtime library (libgcc_s) for O32. For now it seems to work, but I
wonder if it might be more robust to do the test compilation with -c and
-freestanding?
clang: with TARGET_CC=clang, it fails for me. Here are the
relevant excerpts from config.log:
--8<---------------cut here---------------start------------->8---
configure:24700:
/gnu/store/yjmchvkz0kmz4s1sxc0p89imfik68qzg-clang-3.6.0/bin/clang -o conftest
-Os -Wall -W -Wshadow -Wpointer-arith -Wundef -Wchar-subscripts -Wcomment
-Wdeprecated-declarations -Wdisabled-optimization -Wdiv-by-zero -Wfloat-equal
-Wformat-extra-args -Wformat-security -Wformat-y2k -Wimplicit
-Wimplicit-function-declaration -Wimplicit-int -Wmain -Wmissing-braces
-Wmissing-format-attribute -Wmultichar -Wparentheses -Wreturn-type
-Wsequence-point -Wshadow -Wsign-compare -Wswitch -Wtrigraphs -Wunknown-pragmas
-Wunused -Wunused-function -Wunused-label -Wunused-parameter -Wunused-value
-Wunused-variable -Wwrite-strings -Wnested-externs -Wstrict-prototypes -g
-Wredundant-decls -Wmissing-prototypes -Wmissing-declarations -Wcast-align
-Wextra -Wattributes -Wendif-labels -Winit-self -Wint-to-pointer-cast
-Winvalid-pch -Wmissing-field-initializers -Wnonnull -Woverflow -Wvla
-Wpointer-to-int-cast -Wstrict-aliasing -Wvariadic-macros
-Wvolatile-register-var -Wpointer-sign -Wmissing-include-dirs
-Wmissing-prototypes -Wmissing-declarations -Wformat=2 -mabi=32 -Werror -Wall
-W -DGRUB_CPU_MIPSEL=1 -DGRUB_MACHINE_MIPS_LOONGSON=1
-DGRUB_MACHINE=MIPS_LOONGSON -nostdlib -static conftest.c >&5
error: unknown target CPU 'mips32r2'
configure:24700: $? = 1
configure: failed program was:
[...]
configure:24700:
/gnu/store/yjmchvkz0kmz4s1sxc0p89imfik68qzg-clang-3.6.0/bin/clang -o conftest
-Os -Wall -W -Wshadow -Wpointer-arith -Wundef -Wchar-subscripts -Wcomment
-Wdeprecated-declarations -Wdisabled-optimization -Wdiv-by-zero -Wfloat-equal
-Wformat-extra-args -Wformat-security -Wformat-y2k -Wimplicit
-Wimplicit-function-declaration -Wimplicit-int -Wmain -Wmissing-braces
-Wmissing-format-attribute -Wmultichar -Wparentheses -Wreturn-type
-Wsequence-point -Wshadow -Wsign-compare -Wswitch -Wtrigraphs -Wunknown-pragmas
-Wunused -Wunused-function -Wunused-label -Wunused-parameter -Wunused-value
-Wunused-variable -Wwrite-strings -Wnested-externs -Wstrict-prototypes -g
-Wredundant-decls -Wmissing-prototypes -Wmissing-declarations -Wcast-align
-Wextra -Wattributes -Wendif-labels -Winit-self -Wint-to-pointer-cast
-Winvalid-pch -Wmissing-field-initializers -Wnonnull -Woverflow -Wvla
-Wpointer-to-int-cast -Wstrict-aliasing -Wvariadic-macros
-Wvolatile-register-var -Wpointer-sign -Wmissing-include-dirs
-Wmissing-prototypes -Wmissing-declarations -Wformat=2 -target mips -mabi=32
-Werror -Wall -W -DGRUB_CPU_MIPSEL=1 -DGRUB_MACHINE_MIPS_LOONGSON=1
-DGRUB_MACHINE=MIPS_LOONGSON -nostdlib -static conftest.c >&5
ld: /tmp/conftest-efc530.o: compiled for a big endian system and target is
little endian
ld: /tmp/conftest-efc530.o: endianness incompatible with that of the selected
emulation
ld: failed to merge target specific data of file /tmp/conftest-efc530.o
ld: warning: cannot find entry symbol __start; defaulting to 00000000004000f0
collect2: error: ld returned 1 exit status
clang-3.6: error: linker (via gcc) command failed with exit code 1 (use -v to
see invocation)
configure:24700: $? = 1
configure: failed program was:
[...]
--8<---------------cut here---------------end--------------->8---
I guess that "-target mips" is interpreted as requesting big endian.
I suspect that simply passing -mabi=32 is the right thing to do for
clang as well, but that the clang we have built in GNU Guix doesn't
include support for targetting the O32 ABI. It's possible that the only
way to target O32 from a non-multilib N32 system using clang is to do
cross-compilation. Or perhaps we need to explicitly request support for
'mips32r2' when building clang.
Mark
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