ports head -r487783: on armv7 x11/pixman fails to build: /usr/bin/ld: error: can't create dynamic relocation R_ARM_V4BX against local symbol in readonly segment; recompile object files with -fPIC
Mark Millard
marklmi at yahoo.com
Sat Nov 17 02:26:14 UTC 2018
[History omitted. This should stand on its own well.]
I finally figured out parts of the issue, I think.
At least how the V_ARM_V4BX use is getting there
despite lld's status for handling it . . .
On armv7:
# more test_bx_lr.S
.text
.arch armv6
.object_arch armv4
.arm
.altmacro
.p2align 2
.func fname
.global fname
.hidden fname
.type fname, %function
fname:
bx lr
(I got those lines from the failing port's .S files,
including includes. Note the .object_arch armv4 use
and the forced armv6, not armv7.)
# clang -target armv7-unknown-freebsd13.0-gnueabihf -O -pipe -no-integrated-as -MT test_bx_lr.lo -MD -MP -MF test_bx_lr.Tpo -c test_bx_lr.S -fPIC -DPIC -o test_bx_lr.o
(The -target is not necessary. I just choose to be explicit.)
# objdump -x test_bx_lr.o | more
test_bx_lr.o: file format elf32-littlearm
test_bx_lr.o
architecture: armv4, flags 0x00000011:
HAS_RELOC, HAS_SYMS
start address 0x00000000
private flags = 5000000: [Version5 EABI]
Sections:
Idx Name Size VMA LMA File off Algn
0 .text 00000004 00000000 00000000 00000034 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
1 .data 00000000 00000000 00000000 00000038 2**0
CONTENTS, ALLOC, LOAD, DATA
2 .bss 00000000 00000000 00000000 00000038 2**0
ALLOC
3 .ARM.attributes 0000001b 00000000 00000000 00000038 2**0
CONTENTS, READONLY
SYMBOL TABLE:
00000000 l d .text 00000000 .text
00000000 l d .data 00000000 .data
00000000 l d .bss 00000000 .bss
00000000 l d .ARM.attributes 00000000 .ARM.attributes
00000000 g F .text 00000000 .hidden fname
RELOCATION RECORDS FOR [.text]:
OFFSET TYPE VALUE
00000000 R_ARM_V4BX *ABS*
truss for that cc command reports looking in many
places for as, finally finding /usr/local/bin/as :
access("/usr/bin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/bin/as",X_OK|R_OK) ERR#2 'No such file or directory'
(Note: based on WITHOUT_BINUTILS= for buildworld the above would normally
not be found. But for WITH_BINUTILS= the host as would be found.)
access("/sbin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/bin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/sbin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/bin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/local/sbin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/local/bin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/home/markmi/bin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/sbin/as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/bin/as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/sbin/as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/bin/as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/local/sbin/as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/local/bin/as",X_OK|R_OK) = 0 (0x0)
(Note the /usr/home/markmi/bin/armv7-unknown-freebsd13.0-gnueabihf-as attempt
before the one actually found and used. I would not have guessed the
need to worry about such a place.)
Then follows:
fstatat(AT_FDCWD,"/usr/local/bin/as",{ mode=-r-xr-xr-x ,inode=80287,size=21817416,blksize=32768 },0x0) = 0 (0x0)
__sysctl(0xbfbfe020,0x2,0xbfbfe018,0xbfbfe01c,0xe,0x236c9140) = 0 (0x0)
access("/usr/bin/clang",F_OK) = 0 (0x0)
vfork() = 61461 (0xf015)
wait4(61461,{ EXITED,val=0 },0x0,0x0) = 61461 (0xf015)
access("/usr/local/bin/as",F_OK) = 0 (0x0)
vfork() = 61462 (0xf016)
wait4(61462,{ EXITED,val=0 },0x0,0x0) = 61462 (0xf016)
access("/tmp/test_bx_lr-0c7bf8.s",W_OK) = 0 (0x0)
fstatat(AT_FDCWD,"/tmp/test_bx_lr-0c7bf8.s",{ mode=-rw-r--r-- ,inode=802647,size=210,blksize=32768 },0x0) = 0 (0x0)
fstatat(AT_FDCWD,"/tmp/test_bx_lr-0c7bf8.s",{ mode=-rw-r--r-- ,inode=802647,size=210,blksize=32768 },AT_SYMLINK_NOFOLLOW) = 0 (0x0)
fstatat(AT_FDCWD,"/tmp/test_bx_lr-0c7bf8.s",{ mode=-rw-r--r-- ,inode=802647,size=210,blksize=32768 },AT_SYMLINK_NOFOLLOW) = 0 (0x0)
unlink("/tmp/test_bx_lr-0c7bf8.s") = 0 (0x0)
llvm/clang is not providing the assembler used for -no-integrated-as .
This would appear to imply that a system without ports or other such
can not use -no-integrated-as with clang for buildworld buildkernel.
In my normal armv7 command line context the above ends up using:
# /usr/local/bin/as -v
GNU assembler version 2.30 (armv7-portbld-freebsd13.0) using BFD version (GNU Binutils) 2.30
So a GNU toolchain's as is actually in control of what goes in
the .o file in many contexts. It is not clear that all the
alternatives are equivalent for R_ARM_V4BX being generated
or not.
Simplifying the command (but still showing target):
# clang -target armv7-unknown-freebsd13.0-gnueabihf -pipe -no-integrated-as -c test_bx_lr.S -o test_bx_lr.o
# objdump -x test_bx_lr.o | more
test_bx_lr.o: file format elf32-littlearm
test_bx_lr.o
architecture: armv4, flags 0x00000011:
HAS_RELOC, HAS_SYMS
start address 0x00000000
private flags = 5000000: [Version5 EABI]
Sections:
Idx Name Size VMA LMA File off Algn
0 .text 00000004 00000000 00000000 00000034 2**2
CONTENTS, ALLOC, LOAD, RELOC, READONLY, CODE
1 .data 00000000 00000000 00000000 00000038 2**0
CONTENTS, ALLOC, LOAD, DATA
2 .bss 00000000 00000000 00000000 00000038 2**0
ALLOC
3 .ARM.attributes 0000001b 00000000 00000000 00000038 2**0
CONTENTS, READONLY
SYMBOL TABLE:
00000000 l d .text 00000000 .text
00000000 l d .data 00000000 .data
00000000 l d .bss 00000000 .bss
00000000 l d .ARM.attributes 00000000 .ARM.attributes
00000000 g F .text 00000000 .hidden fname
RELOCATION RECORDS FOR [.text]:
OFFSET TYPE VALUE
00000000 R_ARM_V4BX *ABS*
Without the -no-integrated-as the notation in the file is rejected,
with "unknown directive" for .func .
Using poudriere bulk with -i and installing binutils in the
session, I see the same inside my amd64->armv7 cross build
environment. So there still is the question of how R_ARM_V4BX
is handled by various lld's in various contexts. (Or whatever
linker is being used if it is not lld.)
Back to amd64 land . . .
Renaming the existing as files so we can see all the places
searched before not-found is declared (on amd64 with -target
specified):
access("/usr/bin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/bin/as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/bin/x86_64-unknown-freebsd13.0-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/sbin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/bin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/sbin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/bin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/local/sbin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/local/bin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/home/markmi/bin/armv7-unknown-freebsd13.0-gnueabihf-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/sbin/as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/bin/as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/sbin/as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/bin/as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/local/sbin/as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/local/bin/as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/home/markmi/bin/as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/sbin/x86_64-unknown-freebsd13.0-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/bin/x86_64-unknown-freebsd13.0-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/sbin/x86_64-unknown-freebsd13.0-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/bin/x86_64-unknown-freebsd13.0-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/local/sbin/x86_64-unknown-freebsd13.0-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/local/bin/x86_64-unknown-freebsd13.0-as",X_OK|R_OK) ERR#2 'No such file or directory'
access("/usr/home/markmi/bin/x86_64-unknown-freebsd13.0-as",X_OK|R_OK) ERR#2 'No such file or directory'
(Note: It actually explicitly tries to use the x86_64 assembler if it
does not find an armv7 or a generically pathed one. The generically
pathed ones would normally also be x86_64 ones.)
Another thing of note (using aarch64 as an example):
/usr/local/aarch64-unknown-freebsd13.0/bin/as
does not appear to be someplace that clang would find as
but is a place devel/aarch64-binutils puts one.
===
Mark Millard
marklmi at yahoo.com
( dsl-only.net went
away in early 2018-Mar)
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