2 * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
3 * Copyright (C) 2015, Huawei Inc.
7 #include <sys/utsname.h>
10 #include "llvm-utils.h"
13 #define CLANG_BPF_CMD_DEFAULT_TEMPLATE \
14 "$CLANG_EXEC -D__KERNEL__ $CLANG_OPTIONS " \
15 "$KERNEL_INC_OPTIONS -Wno-unused-value " \
16 "-Wno-pointer-sign -working-directory " \
17 "$WORKING_DIR -c \"$CLANG_SOURCE\" -target bpf -O2 -o -"
19 struct llvm_param llvm_param
= {
20 .clang_path
= "clang",
21 .clang_bpf_cmd_template
= CLANG_BPF_CMD_DEFAULT_TEMPLATE
,
25 .user_set_param
= false,
28 int perf_llvm_config(const char *var
, const char *value
)
30 if (prefixcmp(var
, "llvm."))
32 var
+= sizeof("llvm.") - 1;
34 if (!strcmp(var
, "clang-path"))
35 llvm_param
.clang_path
= strdup(value
);
36 else if (!strcmp(var
, "clang-bpf-cmd-template"))
37 llvm_param
.clang_bpf_cmd_template
= strdup(value
);
38 else if (!strcmp(var
, "clang-opt"))
39 llvm_param
.clang_opt
= strdup(value
);
40 else if (!strcmp(var
, "kbuild-dir"))
41 llvm_param
.kbuild_dir
= strdup(value
);
42 else if (!strcmp(var
, "kbuild-opts"))
43 llvm_param
.kbuild_opts
= strdup(value
);
46 llvm_param
.user_set_param
= true;
51 search_program(const char *def
, const char *name
,
54 char *env
, *path
, *tmp
= NULL
;
59 if (def
&& def
[0] != '\0') {
61 if (access(def
, F_OK
) == 0) {
62 strlcpy(output
, def
, PATH_MAX
);
65 } else if (def
[0] != '\0')
77 path
= strtok_r(env
, ":", &tmp
);
79 scnprintf(buf
, sizeof(buf
), "%s/%s", path
, name
);
80 if (access(buf
, F_OK
) == 0) {
81 strlcpy(output
, buf
, PATH_MAX
);
85 path
= strtok_r(NULL
, ":", &tmp
);
92 #define READ_SIZE 4096
94 read_from_pipe(const char *cmd
, void **p_buf
, size_t *p_read_sz
)
99 size_t read_sz
= 0, buf_sz
= 0;
101 file
= popen(cmd
, "r");
103 pr_err("ERROR: unable to popen cmd: %s\n",
108 while (!feof(file
) && !ferror(file
)) {
110 * Make buf_sz always have obe byte extra space so we
111 * can put '\0' there.
113 if (buf_sz
- read_sz
< READ_SIZE
+ 1) {
116 buf_sz
= read_sz
+ READ_SIZE
+ 1;
117 new_buf
= realloc(buf
, buf_sz
);
120 pr_err("ERROR: failed to realloc memory\n");
127 read_sz
+= fread(buf
+ read_sz
, 1, READ_SIZE
, file
);
130 if (buf_sz
- read_sz
< 1) {
131 pr_err("ERROR: internal error\n");
137 pr_err("ERROR: error occurred when reading from pipe: %s\n",
143 err
= WEXITSTATUS(pclose(file
));
151 * If buf is string, give it terminal '\0' to make our life
152 * easier. If buf is not string, that '\0' is out of space
153 * indicated by read_sz so caller won't even notice it.
155 ((char *)buf
)[read_sz
] = '\0';
163 *p_read_sz
= read_sz
;
178 force_set_env(const char *var
, const char *value
)
181 setenv(var
, value
, 1);
182 pr_debug("set env: %s=%s\n", var
, value
);
185 pr_debug("unset env: %s\n", var
);
193 " \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
194 " \tYou may want to try git trunk:\n"
195 " \t\tgit clone http://llvm.org/git/llvm.git\n"
197 " \t\tgit clone http://llvm.org/git/clang.git\n\n"
198 " \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
199 " \tdebian/ubuntu:\n"
200 " \t\thttp://llvm.org/apt\n\n"
201 " \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
202 " \toption in [llvm] section of ~/.perfconfig to:\n\n"
203 " \t \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS \\\n"
204 " \t -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
205 " \t -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
206 " \t(Replace /path/to/llc with path to your llc)\n\n"
210 static int detect_kbuild_dir(char **kbuild_dir
)
212 const char *test_dir
= llvm_param
.kbuild_dir
;
213 const char *prefix_dir
= "";
214 const char *suffix_dir
= "";
217 struct utsname utsname
;
222 err
= uname(&utsname
);
224 pr_warning("uname failed: %s\n", strerror(errno
));
228 test_dir
= utsname
.release
;
229 prefix_dir
= "/lib/modules/";
230 suffix_dir
= "/build";
233 err
= asprintf(&autoconf_path
, "%s%s%s/include/generated/autoconf.h",
234 prefix_dir
, test_dir
, suffix_dir
);
238 if (access(autoconf_path
, R_OK
) == 0) {
241 err
= asprintf(kbuild_dir
, "%s%s%s", prefix_dir
, test_dir
,
251 static const char *kinc_fetch_script
=
252 "#!/usr/bin/env sh\n"
253 "if ! test -d \"$KBUILD_DIR\"\n"
257 "if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
261 "TMPDIR=`mktemp -d`\n"
262 "if test -z \"$TMPDIR\"\n"
266 "cat << EOF > $TMPDIR/Makefile\n"
268 "\\$(obj)/%.o: \\$(src)/%.c\n"
269 "\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
271 "touch $TMPDIR/dummy.c\n"
272 "make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
278 get_kbuild_opts(char **kbuild_dir
, char **kbuild_include_opts
)
282 if (!kbuild_dir
|| !kbuild_include_opts
)
286 *kbuild_include_opts
= NULL
;
288 if (llvm_param
.kbuild_dir
&& !llvm_param
.kbuild_dir
[0]) {
289 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
290 pr_debug("Skip kbuild options detection.\n");
294 err
= detect_kbuild_dir(kbuild_dir
);
297 "WARNING:\tunable to get correct kernel building directory.\n"
298 "Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
299 " \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
300 " \tdetection.\n\n");
304 pr_debug("Kernel build dir is set to %s\n", *kbuild_dir
);
305 force_set_env("KBUILD_DIR", *kbuild_dir
);
306 force_set_env("KBUILD_OPTS", llvm_param
.kbuild_opts
);
307 err
= read_from_pipe(kinc_fetch_script
,
308 (void **)kbuild_include_opts
,
312 "WARNING:\tunable to get kernel include directories from '%s'\n"
313 "Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
314 " \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
315 " \toption in [llvm] to \"\" to suppress this detection.\n\n",
323 pr_debug("include option is set to %s\n", *kbuild_include_opts
);
326 int llvm__compile_bpf(const char *path
, void **p_obj_buf
,
327 size_t *p_obj_buf_sz
)
330 char clang_path
[PATH_MAX
];
331 const char *clang_opt
= llvm_param
.clang_opt
;
332 const char *template = llvm_param
.clang_bpf_cmd_template
;
333 char *kbuild_dir
= NULL
, *kbuild_include_opts
= NULL
;
334 void *obj_buf
= NULL
;
338 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE
;
340 err
= search_program(llvm_param
.clang_path
,
341 "clang", clang_path
);
344 "ERROR:\tunable to find clang.\n"
345 "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
346 " \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
352 * This is an optional work. Even it fail we can continue our
353 * work. Needn't to check error return.
355 get_kbuild_opts(&kbuild_dir
, &kbuild_include_opts
);
357 force_set_env("CLANG_EXEC", clang_path
);
358 force_set_env("CLANG_OPTIONS", clang_opt
);
359 force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts
);
360 force_set_env("WORKING_DIR", kbuild_dir
? : ".");
363 * Since we may reset clang's working dir, path of source file
364 * should be transferred into absolute path, except we want
365 * stdin to be source file (testing).
367 force_set_env("CLANG_SOURCE",
368 (path
[0] == '-') ? path
:
369 make_nonrelative_path(path
));
371 pr_debug("llvm compiling command template: %s\n", template);
372 err
= read_from_pipe(template, &obj_buf
, &obj_buf_sz
);
374 pr_err("ERROR:\tunable to compile %s\n", path
);
375 pr_err("Hint:\tCheck error message shown above.\n");
376 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
377 pr_err(" \t\tclang -target bpf -O2 -c %s\n", path
);
378 pr_err(" \twith proper -I and -D options.\n");
383 free(kbuild_include_opts
);
387 *p_obj_buf
= obj_buf
;
390 *p_obj_buf_sz
= obj_buf_sz
;
394 free(kbuild_include_opts
);
403 int llvm__search_clang(void)
405 char clang_path
[PATH_MAX
];
407 return search_program(llvm_param
.clang_path
, "clang", clang_path
);