Date: Fri, 16 Nov 2018 19:35:14 -0800 From: Mark Millard <marklmi@yahoo.com> To: Jan Beich <jbeich@FreeBSD.org>, FreeBSD Toolchain <freebsd-toolchain@freebsd.org> Cc: ports-list freebsd <freebsd-ports@freebsd.org> Subject: Re: 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 [lld/trunk has afix] Message-ID: <4BEBC4A6-D9F2-4838-8DAB-4B494D4E0B0D@yahoo.com> In-Reply-To: <F744DFE3-DB37-4A95-8C8E-DC1A5507D402@yahoo.com> References: <A76D7D49-E36E-4665-AA4B-D083CCF7D57B@yahoo.com> <a7m8-loy5-wny@FreeBSD.org> <03FFE5BB-777D-40D3-9AA3-C8C359BE1F2B@yahoo.com> <908FD96A-9F8F-4477-8E2F-2C97D49AF35E@yahoo.com> <F744DFE3-DB37-4A95-8C8E-DC1A5507D402@yahoo.com>
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Such timing: https://reviews.llvm.org/D53444 indicates commits to lld/trunk/ELF/Arch/ARM.cpp today (2018-Nov-16) to support R_ARM_V4BX in lld. (No update text below. The above just did not fit well.) On 2018-Nov-16, at 18:49, Mark Millard <marklmi at yahoo.com> wrote: > On 2018-Nov-16, at 18:15, Mark Millard <marklmi at yahoo.com> wrote: >=20 >>=20 >> 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 . . . >>=20 >> On armv7: >>=20 >> # 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 >>=20 >> (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.) >=20 > For reference relative to the use of .object_arch armv4 : >=20 > # grep -r object_arch = /wrkdirs/usr/ports/x11/pixman/work/pixman-0.34.0/pixman/ | more > = /wrkdirs/usr/ports/x11/pixman/work/pixman-0.34.0/pixman/pixman-arm-neon-as= m.S: .object_arch armv4 > = /wrkdirs/usr/ports/x11/pixman/work/pixman-0.34.0/pixman/pixman-arm-simd-as= m-scaled.S: .object_arch armv4 > = /wrkdirs/usr/ports/x11/pixman/work/pixman-0.34.0/pixman/pixman-arm-neon-as= m-bilinear.S:.object_arch armv4 > = /wrkdirs/usr/ports/x11/pixman/work/pixman-0.34.0/pixman/pixman-arm-simd-as= m.S: .object_arch armv4 >=20 > Without .object_arch armv4 the assembler involved does not output > the V_ARM_V4BX *ABS* relocation records (adjusted the small example): >=20 > # objdump -x test_bx_lr.o | more >=20 > test_bx_lr.o: file format elf32-littlearm > test_bx_lr.o > architecture: arm, flags 0x00000010: > HAS_SYMS > start address 0x00000000 > private flags =3D 5000000: [Version5 EABI] >=20 > Sections: > Idx Name Size VMA LMA File off Algn > 0 .text 00000004 00000000 00000000 00000034 2**2 > CONTENTS, ALLOC, LOAD, 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 >=20 >=20 >=20 >> # 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 >>=20 >> (The -target is not necessary. I just choose to be explicit.) >>=20 >> # objdump -x test_bx_lr.o | more >>=20 >> 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 =3D 5000000: [Version5 EABI] >>=20 >> 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 >>=20 >>=20 >> RELOCATION RECORDS FOR [.text]: >> OFFSET TYPE VALUE=20 >> 00000000 R_ARM_V4BX *ABS* >>=20 >>=20 >> truss for that cc command reports looking in many >> places for as, finally finding /usr/local/bin/as : >>=20 >> 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' >>=20 >> (Note: based on WITHOUT_BINUTILS=3D for buildworld the above would = normally >> not be found. But for WITH_BINUTILS=3D the host as would be found.) >>=20 >> 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) =3D 0 (0x0) >>=20 >> (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.) >>=20 >> Then follows: >>=20 >> fstatat(AT_FDCWD,"/usr/local/bin/as",{ mode=3D-r-xr-xr-x = ,inode=3D80287,size=3D21817416,blksize=3D32768 },0x0) =3D 0 (0x0) >> __sysctl(0xbfbfe020,0x2,0xbfbfe018,0xbfbfe01c,0xe,0x236c9140) =3D 0 = (0x0) >> access("/usr/bin/clang",F_OK) =3D 0 (0x0) >> vfork() =3D 61461 = (0xf015) >> wait4(61461,{ EXITED,val=3D0 },0x0,0x0) =3D 61461 = (0xf015) >> access("/usr/local/bin/as",F_OK) =3D 0 (0x0) >> vfork() =3D 61462 = (0xf016) >> wait4(61462,{ EXITED,val=3D0 },0x0,0x0) =3D 61462 = (0xf016) >> access("/tmp/test_bx_lr-0c7bf8.s",W_OK) =3D 0 (0x0) >> fstatat(AT_FDCWD,"/tmp/test_bx_lr-0c7bf8.s",{ mode=3D-rw-r--r-- = ,inode=3D802647,size=3D210,blksize=3D32768 },0x0) =3D 0 (0x0) >> fstatat(AT_FDCWD,"/tmp/test_bx_lr-0c7bf8.s",{ mode=3D-rw-r--r-- = ,inode=3D802647,size=3D210,blksize=3D32768 },AT_SYMLINK_NOFOLLOW) =3D 0 = (0x0) >> fstatat(AT_FDCWD,"/tmp/test_bx_lr-0c7bf8.s",{ mode=3D-rw-r--r-- = ,inode=3D802647,size=3D210,blksize=3D32768 },AT_SYMLINK_NOFOLLOW) =3D 0 = (0x0) >> unlink("/tmp/test_bx_lr-0c7bf8.s") =3D 0 (0x0) >>=20 >> 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. >>=20 >> In my normal armv7 command line context the above ends up using: >>=20 >> # /usr/local/bin/as -v >> GNU assembler version 2.30 (armv7-portbld-freebsd13.0) using BFD = version (GNU Binutils) 2.30 >>=20 >> 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. >>=20 >>=20 >> Simplifying the command (but still showing target): >>=20 >> # clang -target armv7-unknown-freebsd13.0-gnueabihf -pipe = -no-integrated-as -c test_bx_lr.S -o test_bx_lr.o >>=20 >> # objdump -x test_bx_lr.o | more >>=20 >> 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 =3D 5000000: [Version5 EABI] >>=20 >> 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 >>=20 >>=20 >> RELOCATION RECORDS FOR [.text]: >> OFFSET TYPE VALUE=20 >> 00000000 R_ARM_V4BX *ABS* >>=20 >>=20 >> Without the -no-integrated-as the notation in the file is rejected, >> with "unknown directive" for .func . >>=20 >>=20 >>=20 >> 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.) >>=20 >> Back to amd64 land . . . >>=20 >> Renaming the existing as files so we can see all the places >> searched before not-found is declared (on amd64 with -target >> specified): >>=20 >> 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' >>=20 >> (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.) >>=20 >>=20 >> Another thing of note (using aarch64 as an example): >>=20 >> /usr/local/aarch64-unknown-freebsd13.0/bin/as >>=20 >> does not appear to be someplace that clang would find as >> but is a place devel/aarch64-binutils puts one. =3D=3D=3D Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)
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