forked from Minki/linux
cb76371441
The newly added 'llvm.opts' variable allows passing options directly to
llc, like needed to get sane DWARF in BPF ELF debug sections:
With:
[root@seventh perf]# cat ~/.perfconfig
[llvm]
dump-obj = true
clang-opt = -g
[root@seventh perf]#
We get:
[root@seventh perf]# perf trace -e tools/perf/examples/bpf/hello.c cat /etc/passwd > /dev/null
LLVM: dumping tools/perf/examples/bpf/hello.o
0.000 __bpf_stdout__:Hello, world
0.015 __bpf_stdout__:Hello, world
0.187 __bpf_stdout__:Hello, world
[root@seventh perf]# pahole tools/perf/examples/bpf/hello.o
struct clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c) {
clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566e.org clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c); /* 0 4 */
clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566e.org clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c); /* 4 4 */
clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566e.org clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c); /* 8 4 */
clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566e.org clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c); /* 12 4 */
clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566e.org clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c); /* 16 4 */
clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566e.org clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c); /* 20 4 */
clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566e.org clang version 8.0.0 (http://llvm.org/git/clang.git 8587270a739ee30c926a76d5657e65e85b560f6e) (http://llvm.org/git/llvm.git 0566eefef9c3777bd780ec4cbb9efa764633b76c); /* 24 4 */
/* size: 28, cachelines: 1, members: 7 */
/* last cacheline: 28 bytes */
};
[root@seventh perf]#
Adding these options to be passed to llvm's llc:
[root@seventh perf]# cat ~/.perfconfig
[llvm]
dump-obj = true
clang-opt = -g
opts = -mattr=dwarfris
[root@seventh perf]#
We get sane output:
[root@seventh perf]# perf trace -e tools/perf/examples/bpf/hello.c cat /etc/passwd > /dev/null
LLVM: dumping tools/perf/examples/bpf/hello.o
0.000 __bpf_stdout__:Hello, world
0.015 __bpf_stdout__:Hello, world
0.185 __bpf_stdout__:Hello, world
[root@seventh perf]# pahole tools/perf/examples/bpf/hello.o
struct bpf_map {
unsigned int type; /* 0 4 */
unsigned int key_size; /* 4 4 */
unsigned int value_size; /* 8 4 */
unsigned int max_entries; /* 12 4 */
unsigned int map_flags; /* 16 4 */
unsigned int inner_map_idx; /* 20 4 */
unsigned int numa_node; /* 24 4 */
/* size: 28, cachelines: 1, members: 7 */
/* last cacheline: 28 bytes */
};
[root@seventh perf]#
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>,
Cc: Yonghong Song <yhs@fb.com>
Link: https://lkml.kernel.org/n/tip-0lrwmrip4dru1651rm8xa7tq@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
70 lines
2.0 KiB
C
70 lines
2.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
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* Copyright (C) 2015, Huawei Inc.
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*/
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#ifndef __LLVM_UTILS_H
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#define __LLVM_UTILS_H
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#include "debug.h"
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struct llvm_param {
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/* Path of clang executable */
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const char *clang_path;
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/* Path of llc executable */
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const char *llc_path;
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/*
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* Template of clang bpf compiling. 5 env variables
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* can be used:
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* $CLANG_EXEC: Path to clang.
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* $CLANG_OPTIONS: Extra options to clang.
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* $KERNEL_INC_OPTIONS: Kernel include directories.
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* $WORKING_DIR: Kernel source directory.
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* $CLANG_SOURCE: Source file to be compiled.
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*/
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const char *clang_bpf_cmd_template;
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/* Will be filled in $CLANG_OPTIONS */
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const char *clang_opt;
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/*
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* If present it'll add -emit-llvm to $CLANG_OPTIONS to pipe
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* the clang output to llc, useful for new llvm options not
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* yet selectable via 'clang -mllvm option', such as -mattr=dwarfris
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* in clang 6.0/llvm 7
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*/
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const char *opts;
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/* Where to find kbuild system */
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const char *kbuild_dir;
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/*
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* Arguments passed to make, like 'ARCH=arm' if doing cross
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* compiling. Should not be used for dynamic compiling.
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*/
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const char *kbuild_opts;
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/*
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* Default is false. If set to true, write compiling result
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* to object file.
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*/
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bool dump_obj;
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/*
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* Default is false. If one of the above fields is set by user
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* explicitly then user_set_llvm is set to true. This is used
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* for perf test. If user doesn't set anything in .perfconfig
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* and clang is not found, don't trigger llvm test.
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*/
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bool user_set_param;
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};
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extern struct llvm_param llvm_param;
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int perf_llvm_config(const char *var, const char *value);
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int llvm__compile_bpf(const char *path, void **p_obj_buf, size_t *p_obj_buf_sz);
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/* This function is for test__llvm() use only */
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int llvm__search_clang(void);
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/* Following functions are reused by builtin clang support */
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void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts);
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int llvm__get_nr_cpus(void);
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void llvm__dump_obj(const char *path, void *obj_buf, size_t size);
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#endif
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