[llvm-bugs] [Bug 39885] New: lld does not link clang-compiled openmp code that uses -fopenmp-targets option
via llvm-bugs
llvm-bugs at lists.llvm.org
Tue Dec 4 17:31:23 PST 2018
https://bugs.llvm.org/show_bug.cgi?id=39885
Bug ID: 39885
Summary: lld does not link clang-compiled openmp code that uses
-fopenmp-targets option
Product: lld
Version: unspecified
Hardware: Other
OS: Linux
Status: NEW
Severity: normal
Priority: P
Component: ELF
Assignee: unassignedbugs at nondot.org
Reporter: deachempat at cray.com
CC: llvm-bugs at lists.llvm.org, peter.smith at linaro.org
I have a clang compiler configured to use lld as the linker and that uses the
openmp runtime for compiling OpenMP programs.
When I compile the attached test code like this:
clang -v -dynamic -fopenmp -fopenmp-targets=x86_64 -save-temps
omp_target_simple.c
I see the following error during the link step:
"/home/users/deachempat/ptmp/clang-devel/fresh/build/bin/ld.lld" -z relro
--hash-style=gnu --hash-style=both --enable-new-dtags --eh-frame-hdr -m
elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o a.out
/usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../lib64/crt1.o
/usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../lib64/crti.o
/usr/lib64/gcc/x86_64-suse-linux/4.8/crtbegin.o
-L/usr/lib64/gcc/x86_64-suse-linux/4.8
-L/usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../lib64 -L/lib/../lib64
-L/usr/lib/../lib64
-L/usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../x86_64-suse-linux/lib
-L/usr/lib64/gcc/x86_64-suse-linux/4.8/../../..
-L/ptmp/deachempat/clang-devel/fresh/build/bin/../lib -L/lib -L/usr/lib
omp-target-simple-host-x86_64-unknown-linux-gnu.o -lomp -lomptarget -lgcc
--as-needed -lgcc_s --no-as-needed -lpthread -lc -lgcc --as-needed -lgcc_s
--no-as-needed /usr/lib64/gcc/x86_64-suse-linux/4.8/crtend.o
/usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../lib64/crtn.o -T a.lk
ld.lld: error: a.lk:13: unknown command a.out-openmp-x86_64
>>> a.out-openmp-x86_64
>>> ^
clang-8: error: linker command failed with exit code 1 (use -v to see
invocation)
The generated linker script looks like this:
/*
OpenMP Offload Linker Script
*** Automatically generated by Clang ***
*/
TARGET(binary)
INPUT(a.out-openmp-x86_64)
SECTIONS
{
.omp_offloading.x86_64 :
ALIGN(0x10)
{
PROVIDE_HIDDEN(.omp_offloading.img_start.x86_64 = .);
a.out-openmp-x86_64
PROVIDE_HIDDEN(.omp_offloading.img_end.x86_64 = .);
}
.omp_offloading.entries :
ALIGN(0x10)
SUBALIGN(0x01)
{
PROVIDE_HIDDEN(.omp_offloading.entries_begin = .);
*(.omp_offloading.entries)
PROVIDE_HIDDEN(.omp_offloading.entries_end = .);
}
}
INSERT BEFORE .data
I tried manually modifying a.out-openmp-x86_64 line to a.out-openmp-x86_64(*).
I then hit this error:
$ /home/users/deachempat/ptmp/clang-devel/fresh/build/bin/ld.lld -z relro
--hash-style=gnu --hash-style=both --enable-new-dtags --eh-frame-hdr -m
elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o a.out
/usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../lib64/crt1.o
/usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../lib64/crti.o
/usr/lib64/gcc/x86_64-suse-linux/4.8/crtbegin.o
-L/usr/lib64/gcc/x86_64-suse-linux/4.8
-L/usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../lib64 -L/lib/../lib64
-L/usr/lib/../lib64
-L/usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../x86_64-suse-linux/lib
-L/usr/lib64/gcc/x86_64-suse-linux/4.8/../../..
-L/ptmp/deachempat/clang-devel/fresh/build/bin/../lib -L/lib -L/usr/lib
omp-target-simple-host-x86_64-unknown-linux-gnu.o -lomp -lomptarget -lgcc
--as-needed -lgcc_s --no-as-needed -lpthread -lc -lgcc --as-needed -lgcc_s
--no-as-needed /usr/lib64/gcc/x86_64-suse-linux/4.8/crtend.o
/usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../lib64/crtn.o -T a.lk
ld.lld: error: unable to INSERT AFTER/BEFORE .data: section not defined
Here are the sections that are defined in
omp-target-simple-host-x86_64-unknown-linux-gnu.o:
$ readelf -S -W omp-target-simple-host-x86_64-unknown-linux-gnu.o
There are 27 section headers, starting at offset 0x1340:
Section Headers:
[Nr] Name Type Address Off Size ES Flg
Lk Inf Al
[ 0] NULL 0000000000000000 000000 000000 00
0 0 0
[ 1] .strtab STRTAB 0000000000000000 000fdd 000360 00
0 0 1
[ 2] .text PROGBITS 0000000000000000 000040 0004e5 00 AX
0 0 16
[ 3] .rela.text RELA 0000000000000000 000b60 0001e0 18
26 2 8
[ 4] .group GROUP 0000000000000000 0007f0 000024 04
26 18 4
[ 5] .text.startup PROGBITS 0000000000000000 000530 000081 00 AXG
0 0 16
[ 6] .rela.text.startup RELA 0000000000000000 000d40 0000c0 18 G
26 5 8
[ 7] .rodata.str1.1 PROGBITS 0000000000000000 0005b1 000029 01 AMS
0 0 1
[ 8] .data PROGBITS 0000000000000000 0005e0 000048 00 WA
0 0 8
[ 9] .rela.data RELA 0000000000000000 000e00 000048 18
26 8 8
[10] .rodata PROGBITS 0000000000000000 000628 000001 00 A
0 0 1
[11] .rodata.cst16 PROGBITS 0000000000000000 000630 000020 10 AM
0 0 8
[12] .rodata.str1.16 PROGBITS 0000000000000000 000650 000026 01 AMS
0 0 16
[13] .omp_offloading.entries PROGBITS 0000000000000000 000676 000020
00 A 0 0 1
[14] .rela.omp_offloading.entries RELA 0000000000000000 000e48
000030 18 26 13 8
[15] .rodata..omp_offloading.device_images PROGBITS 0000000000000000
000698 000020 00 AG 0 0 8
[16] .rela.rodata..omp_offloading.device_images RELA
0000000000000000 000e78 000060 18 G 26 15 8
[17] .rodata..omp_offloading.descriptor PROGBITS 0000000000000000
0006b8 000020 00 AG 0 0 8
[18] .rela.rodata..omp_offloading.descriptor RELA 0000000000000000
000ed8 000048 18 G 26 17 8
[19] .init_array.0 INIT_ARRAY 0000000000000000 0006d8 000008 00 WAG
0 0 8
[20] .rela.init_array.0 RELA 0000000000000000 000f20 000018 18 G
26 19 8
[21] .comment PROGBITS 0000000000000000 0006e0 000038 01 MS
0 0 1
[22] .note.GNU-stack PROGBITS 0000000000000000 000718 000000 00
0 0 1
[23] .eh_frame X86_64_UNWIND 0000000000000000 000718 0000d8 00 A
0 0 8
[24] .rela.eh_frame RELA 0000000000000000 000f38 000090 18
26 23 8
[25] .llvm_addrsig LOOS+0xfff4c03 0000000000000000 000fc8 000015 00 E
26 0 1
[26] .symtab SYMTAB 0000000000000000 000818 000348 18
1 17 8
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings), I (info),
L (link order), O (extra OS processing required), G (group), T (TLS),
C (compressed), x (unknown), o (OS specific), E (exclude),
l (large), p (processor specific)
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