FYI, just noticed, recently updated clang to version 6, from its
upstream git repo.
root@jouet ~]# perf test -v LLVM
37: LLVM search and compile :
37.1: Basic BPF llvm compile :
--- start ---
test child forked, pid 5255
Kernel build dir is set to /lib/modules/4.14.0+/build
set env: KBUILD_DIR=/lib/modules/4.14.0+/build
unset env: KBUILD_OPTS
include option is set to -nostdinc -isystem
/usr/lib/gcc/x86_64-redhat-linux/7/include
-I/home/acme/git/linux/arch/x86/include -I./arch/x86/include/generated
-I/home/acme/git/linux/include -I./include
-I/home/acme/git/linux/arch/x86/include/uapi
-I./arch/x86/include/generated/uapi -I/home/acme/git/linux/include/uapi
-I./include/generated/uapi -include
/home/acme/git/linux/include/linux/kconfig.h
set env: NR_CPUS=4
set env: LINUX_VERSION_CODE=0x40e00
set env: CLANG_EXEC=/usr/local/bin/clang
set env: CLANG_OPTIONS=-xc
set env: KERNEL_INC_OPTIONS= -nostdinc -isystem
/usr/lib/gcc/x86_64-redhat-linux/7/include
-I/home/acme/git/linux/arch/x86/include -I./arch/x86/include/generated
-I/home/acme/git/linux/include -I./include
-I/home/acme/git/linux/arch/x86/include/uapi
-I./arch/x86/include/generated/uapi -I/home/acme/git/linux/include/uapi
-I./include/generated/uapi -include
/home/acme/git/linux/include/linux/kconfig.h
set env: WORKING_DIR=/lib/modules/4.14.0+/build
set env: CLANG_SOURCE=-
llvm compiling command template: echo '/*
* bpf-script-example.c
* Test basic LLVM building
*/
#ifndef LINUX_VERSION_CODE
# error Need LINUX_VERSION_CODE
# error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200"
into llvm section of ~/.perfconfig'
#endif
#define BPF_ANY 0
#define BPF_MAP_TYPE_ARRAY 2
#define BPF_FUNC_map_lookup_elem 1
#define BPF_FUNC_map_update_elem 2
static void *(*bpf_map_lookup_elem)(void *map, void *key) =
(void *) BPF_FUNC_map_lookup_elem;
static void *(*bpf_map_update_elem)(void *map, void *key, void *value, int
flags) =
(void *) BPF_FUNC_map_update_elem;
struct bpf_map_def {
unsigned int type;
unsigned int key_size;
unsigned int value_size;
unsigned int max_entries;
};
#define SEC(NAME) __attribute__((section(NAME), used))
struct bpf_map_def SEC("maps") flip_table = {
.type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(int),
.value_size = sizeof(int),
.max_entries = 1,
};
SEC("func=SyS_epoll_wait")
int bpf_func__SyS_epoll_wait(void *ctx)
{
int ind =0;
int *flag = bpf_map_lookup_elem(&flip_table, &ind);
int new_flag;
if (!flag)
return 0;
/* flip flag and store back */
new_flag = !*flag;
bpf_map_update_elem(&flip_table, &ind, &new_flag, BPF_ANY);
return new_flag;
}
char _license[] SEC("license") = "GPL";
int _version SEC("version") = LINUX_VERSION_CODE;
' | $CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS
-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE $CLANG_OPTIONS $KERNEL_INC_OPTIONS
-Wno-unused-value -Wno-pointer-sign -working-directory $WORKING_DIR -c
"$CLANG_SOURCE" -target bpf -O2 -o -
test child finished with 0
---- end ----
LLVM search and compile subtest 0: Ok
37.2: kbuild searching :
--- start ---
test child forked, pid 5728
Kernel build dir is set to /lib/modules/4.14.0+/build
set env: KBUILD_DIR=/lib/modules/4.14.0+/build
unset env: KBUILD_OPTS
include option is set to -nostdinc -isystem
/usr/lib/gcc/x86_64-redhat-linux/7/include
-I/home/acme/git/linux/arch/x86/include -I./arch/x86/include/generated
-I/home/acme/git/linux/include -I./include
-I/home/acme/git/linux/arch/x86/include/uapi
-I./arch/x86/include/generated/uapi -I/home/acme/git/linux/include/uapi
-I./include/generated/uapi -include
/home/acme/git/linux/include/linux/kconfig.h
set env: NR_CPUS=4
set env: LINUX_VERSION_CODE=0x40e00
set env: CLANG_EXEC=/usr/local/bin/clang
set env: CLANG_OPTIONS=-xc
set env: KERNEL_INC_OPTIONS= -nostdinc -isystem
/usr/lib/gcc/x86_64-redhat-linux/7/include
-I/home/acme/git/linux/arch/x86/include -I./arch/x86/include/generated
-I/home/acme/git/linux/include -I./include
-I/home/acme/git/linux/arch/x86/include/uapi
-I./arch/x86/include/generated/uapi -I/home/acme/git/linux/include/uapi
-I./include/generated/uapi -include
/home/acme/git/linux/include/linux/kconfig.h
set env: WORKING_DIR=/lib/modules/4.14.0+/build
set env: CLANG_SOURCE=-
llvm compiling command template: echo '/*
* bpf-script-test-kbuild.c
* Test include from kernel header
*/
#ifndef LINUX_VERSION_CODE
# error Need LINUX_VERSION_CODE
# error Example: for 4.2 kernel, put 'clang-opt="-DLINUX_VERSION_CODE=0x40200"
into llvm section of ~/.perfconfig'
#endif
#define SEC(NAME) __attribute__((section(NAME), used))
#include <uapi/linux/fs.h>
#include <uapi/asm/ptrace.h>
SEC("func=vfs_llseek")
int bpf_func__vfs_llseek(void *ctx)
{
return 0;
}
char _license[] SEC("license") = "GPL";
int _version SEC("version") = LINUX_VERSION_CODE;
' | $CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS
-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE $CLANG_OPTIONS $KERNEL_INC_OPTIONS
-Wno-unused-value -Wno-pointer-sign -working-directory $WORKING_DIR -c
"$CLANG_SOURCE" -target bpf -O2 -o -
In file included from <stdin>:12:
In file included from /home/acme/git/linux/arch/x86/include/uapi/asm/ptrace.h:5:
In file included from /home/acme/git/linux/include/linux/compiler.h:237:
In file included from /home/acme/git/linux/arch/x86/include/asm/barrier.h:5:
In file included from
/home/acme/git/linux/arch/x86/include/asm/alternative.h:10:
/home/acme/git/linux/arch/x86/include/asm/asm.h:145:50: error: unknown register
name 'esp' in asm
register unsigned long current_stack_pointer asm(_ASM_SP);
^
/home/acme/git/linux/arch/x86/include/asm/asm.h:44:18: note: expanded from
macro '_ASM_SP'
#define _ASM_SP __ASM_REG(sp)
^
/home/acme/git/linux/arch/x86/include/asm/asm.h:27:32: note: expanded from
macro '__ASM_REG'
#define __ASM_REG(reg) __ASM_SEL_RAW(e##reg, r##reg)
^
/home/acme/git/linux/arch/x86/include/asm/asm.h:18:29: note: expanded from
macro '__ASM_SEL_RAW'
# define __ASM_SEL_RAW(a,b) __ASM_FORM_RAW(a)
^
/home/acme/git/linux/arch/x86/include/asm/asm.h:11:32: note: expanded from
macro '__ASM_FORM_RAW'
# define __ASM_FORM_RAW(x) #x
^
<scratch space>:4:1: note: expanded from here
"esp"
^
1 error generated.
ERROR: unable to compile -
Hint: Check error message shown above.
Hint: You can also pre-compile it into .o using:
clang -target bpf -O2 -c -
with proper -I and -D options.
Failed to compile test case: 'kbuild searching'
test child finished with -1
---- end ----
LLVM search and compile subtest 1: FAILED!
37.3: Compile source for BPF prologue generation :
--- force skipped ---
LLVM search and compile subtest 2: Skip
37.4: Compile source for BPF relocation :
--- force skipped ---
LLVM search and compile subtest 3: Skip
[root@jouet ~]# clang -v
clang version 6.0.0 (http://llvm.org/git/clang.git
56cc8f8880db2ebc433eeb6b6a707c101467a186) (http://llvm.org/git/llvm.git
3656d83960a4f3fedf6d8f19043abf52379f78c3)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-redhat-linux/7
Selected GCC installation: /usr/lib/gcc/x86_64-redhat-linux/7
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64
[root@jouet ~]#
