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perf llvm: Allow passing options to llc in addition to clang

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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>
This commit is contained in:
Arnaldo Carvalho de Melo 2018-08-15 17:07:01 -03:00
parent 49836f7811
commit cb76371441
2 changed files with 38 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
tools/perf/util/llvm-utils.c
View File

@ -22,12 +22,14 @@
"$CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS " \ "$CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS " \
"-Wno-unused-value -Wno-pointer-sign " \ "-Wno-unused-value -Wno-pointer-sign " \
"-working-directory $WORKING_DIR " \ "-working-directory $WORKING_DIR " \
"-c \"$CLANG_SOURCE\" -target bpf -O2 -o -" "-c \"$CLANG_SOURCE\" -target bpf $CLANG_EMIT_LLVM -O2 -o - $LLVM_OPTIONS_PIPE"
struct llvm_param llvm_param = { struct llvm_param llvm_param = {
.clang_path = "clang", .clang_path = "clang",
.llc_path = "llc",
.clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE, .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
.clang_opt = NULL, .clang_opt = NULL,
.opts = NULL,
.kbuild_dir = NULL, .kbuild_dir = NULL,
.kbuild_opts = NULL, .kbuild_opts = NULL,
.user_set_param = false, .user_set_param = false,
@ -51,6 +53,8 @@ int perf_llvm_config(const char *var, const char *value)
llvm_param.kbuild_opts = strdup(value); llvm_param.kbuild_opts = strdup(value);
else if (!strcmp(var, "dump-obj")) else if (!strcmp(var, "dump-obj"))
llvm_param.dump_obj = !!perf_config_bool(var, value); llvm_param.dump_obj = !!perf_config_bool(var, value);
else if (!strcmp(var, "opts"))
llvm_param.opts = strdup(value);
else { else {
pr_debug("Invalid LLVM config option: %s\n", value); pr_debug("Invalid LLVM config option: %s\n", value);
return -1; return -1;
@ -430,11 +434,13 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf,
unsigned int kernel_version; unsigned int kernel_version;
char linux_version_code_str[64]; char linux_version_code_str[64];
const char *clang_opt = llvm_param.clang_opt; const char *clang_opt = llvm_param.clang_opt;
char clang_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64]; char clang_path[PATH_MAX], llc_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
char serr[STRERR_BUFSIZE]; char serr[STRERR_BUFSIZE];
char *kbuild_dir = NULL, *kbuild_include_opts = NULL, char *kbuild_dir = NULL, *kbuild_include_opts = NULL,
*perf_bpf_include_opts = NULL; *perf_bpf_include_opts = NULL;
const char *template = llvm_param.clang_bpf_cmd_template; const char *template = llvm_param.clang_bpf_cmd_template;
char *pipe_template = NULL;
const char *opts = llvm_param.opts;
char *command_echo = NULL, *command_out; char *command_echo = NULL, *command_out;
char *perf_include_dir = system_path(PERF_INCLUDE_DIR); char *perf_include_dir = system_path(PERF_INCLUDE_DIR);
@ -484,6 +490,26 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf,
force_set_env("PERF_BPF_INC_OPTIONS", perf_bpf_include_opts); force_set_env("PERF_BPF_INC_OPTIONS", perf_bpf_include_opts);
force_set_env("WORKING_DIR", kbuild_dir ? : "."); force_set_env("WORKING_DIR", kbuild_dir ? : ".");
if (opts) {
err = search_program(llvm_param.llc_path, "llc", llc_path);
if (err) {
pr_err("ERROR:\tunable to find llc.\n"
"Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
" \tand 'llc-path' option in [llvm] section of ~/.perfconfig.\n");
version_notice();
goto errout;
}
if (asprintf(&pipe_template, "%s -emit-llvm | %s -march=bpf %s -filetype=obj -o -",
template, llc_path, opts) < 0) {
pr_err("ERROR:\tnot enough memory to setup command line\n");
goto errout;
}
template = pipe_template;
}
/* /*
* Since we may reset clang's working dir, path of source file * Since we may reset clang's working dir, path of source file
* should be transferred into absolute path, except we want * should be transferred into absolute path, except we want
@ -535,6 +561,7 @@ int llvm__compile_bpf(const char *path, void **p_obj_buf,
free(obj_buf); free(obj_buf);
free(perf_bpf_include_opts); free(perf_bpf_include_opts);
free(perf_include_dir); free(perf_include_dir);
free(pipe_template);
if (p_obj_buf) if (p_obj_buf)
*p_obj_buf = NULL; *p_obj_buf = NULL;
if (p_obj_buf_sz) if (p_obj_buf_sz)

9
tools/perf/util/llvm-utils.h
View File

@ -11,6 +11,8 @@
struct llvm_param { struct llvm_param {
/* Path of clang executable */ /* Path of clang executable */
const char *clang_path; const char *clang_path;
/* Path of llc executable */
const char *llc_path;
/* /*
* Template of clang bpf compiling. 5 env variables * Template of clang bpf compiling. 5 env variables
* can be used: * can be used:
@ -23,6 +25,13 @@ struct llvm_param {
const char *clang_bpf_cmd_template; const char *clang_bpf_cmd_template;
/* Will be filled in $CLANG_OPTIONS */ /* Will be filled in $CLANG_OPTIONS */
const char *clang_opt; const char *clang_opt;
/*
* If present it'll add -emit-llvm to $CLANG_OPTIONS to pipe
* the clang output to llc, useful for new llvm options not
* yet selectable via 'clang -mllvm option', such as -mattr=dwarfris
* in clang 6.0/llvm 7
*/
const char *opts;
/* Where to find kbuild system */ /* Where to find kbuild system */
const char *kbuild_dir; const char *kbuild_dir;
/* /*