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6
7#include <errno.h>
8#include <limits.h>
9#include <stdio.h>
10#include <stdlib.h>
11#include <linux/err.h>
12#include <linux/zalloc.h>
13#include "debug.h"
14#include "llvm-utils.h"
15#include "config.h"
16#include "util.h"
17#include <sys/wait.h>
18#include <subcmd/exec-cmd.h>
19
20#define CLANG_BPF_CMD_DEFAULT_TEMPLATE \
21 "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
22 "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE " \
23 "$CLANG_OPTIONS $PERF_BPF_INC_OPTIONS $KERNEL_INC_OPTIONS " \
24 "-Wno-unused-value -Wno-pointer-sign " \
25 "-working-directory $WORKING_DIR " \
26 "-c \"$CLANG_SOURCE\" -target bpf $CLANG_EMIT_LLVM -O2 -o - $LLVM_OPTIONS_PIPE"
27
28struct llvm_param llvm_param = {
29 .clang_path = "clang",
30 .llc_path = "llc",
31 .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
32 .clang_opt = NULL,
33 .opts = NULL,
34 .kbuild_dir = NULL,
35 .kbuild_opts = NULL,
36 .user_set_param = false,
37};
38
39int perf_llvm_config(const char *var, const char *value)
40{
41 if (!strstarts(var, "llvm."))
42 return 0;
43 var += sizeof("llvm.") - 1;
44
45 if (!strcmp(var, "clang-path"))
46 llvm_param.clang_path = strdup(value);
47 else if (!strcmp(var, "clang-bpf-cmd-template"))
48 llvm_param.clang_bpf_cmd_template = strdup(value);
49 else if (!strcmp(var, "clang-opt"))
50 llvm_param.clang_opt = strdup(value);
51 else if (!strcmp(var, "kbuild-dir"))
52 llvm_param.kbuild_dir = strdup(value);
53 else if (!strcmp(var, "kbuild-opts"))
54 llvm_param.kbuild_opts = strdup(value);
55 else if (!strcmp(var, "dump-obj"))
56 llvm_param.dump_obj = !!perf_config_bool(var, value);
57 else if (!strcmp(var, "opts"))
58 llvm_param.opts = strdup(value);
59 else {
60 pr_debug("Invalid LLVM config option: %s\n", value);
61 return -1;
62 }
63 llvm_param.user_set_param = true;
64 return 0;
65}
66
67static int
68search_program(const char *def, const char *name,
69 char *output)
70{
71 char *env, *path, *tmp = NULL;
72 char buf[PATH_MAX];
73 int ret;
74
75 output[0] = '\0';
76 if (def && def[0] != '\0') {
77 if (def[0] == '/') {
78 if (access(def, F_OK) == 0) {
79 strlcpy(output, def, PATH_MAX);
80 return 0;
81 }
82 } else if (def[0] != '\0')
83 name = def;
84 }
85
86 env = getenv("PATH");
87 if (!env)
88 return -1;
89 env = strdup(env);
90 if (!env)
91 return -1;
92
93 ret = -ENOENT;
94 path = strtok_r(env, ":", &tmp);
95 while (path) {
96 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
97 if (access(buf, F_OK) == 0) {
98 strlcpy(output, buf, PATH_MAX);
99 ret = 0;
100 break;
101 }
102 path = strtok_r(NULL, ":", &tmp);
103 }
104
105 free(env);
106 return ret;
107}
108
109#define READ_SIZE 4096
110static int
111read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
112{
113 int err = 0;
114 void *buf = NULL;
115 FILE *file = NULL;
116 size_t read_sz = 0, buf_sz = 0;
117 char serr[STRERR_BUFSIZE];
118
119 file = popen(cmd, "r");
120 if (!file) {
121 pr_err("ERROR: unable to popen cmd: %s\n",
122 str_error_r(errno, serr, sizeof(serr)));
123 return -EINVAL;
124 }
125
126 while (!feof(file) && !ferror(file)) {
127
128
129
130
131 if (buf_sz - read_sz < READ_SIZE + 1) {
132 void *new_buf;
133
134 buf_sz = read_sz + READ_SIZE + 1;
135 new_buf = realloc(buf, buf_sz);
136
137 if (!new_buf) {
138 pr_err("ERROR: failed to realloc memory\n");
139 err = -ENOMEM;
140 goto errout;
141 }
142
143 buf = new_buf;
144 }
145 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
146 }
147
148 if (buf_sz - read_sz < 1) {
149 pr_err("ERROR: internal error\n");
150 err = -EINVAL;
151 goto errout;
152 }
153
154 if (ferror(file)) {
155 pr_err("ERROR: error occurred when reading from pipe: %s\n",
156 str_error_r(errno, serr, sizeof(serr)));
157 err = -EIO;
158 goto errout;
159 }
160
161 err = WEXITSTATUS(pclose(file));
162 file = NULL;
163 if (err) {
164 err = -EINVAL;
165 goto errout;
166 }
167
168
169
170
171
172
173 ((char *)buf)[read_sz] = '\0';
174
175 if (!p_buf)
176 free(buf);
177 else
178 *p_buf = buf;
179
180 if (p_read_sz)
181 *p_read_sz = read_sz;
182 return 0;
183
184errout:
185 if (file)
186 pclose(file);
187 free(buf);
188 if (p_buf)
189 *p_buf = NULL;
190 if (p_read_sz)
191 *p_read_sz = 0;
192 return err;
193}
194
195static inline void
196force_set_env(const char *var, const char *value)
197{
198 if (value) {
199 setenv(var, value, 1);
200 pr_debug("set env: %s=%s\n", var, value);
201 } else {
202 unsetenv(var);
203 pr_debug("unset env: %s\n", var);
204 }
205}
206
207static void
208version_notice(void)
209{
210 pr_err(
211" \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
212" \tYou may want to try git trunk:\n"
213" \t\tgit clone http://llvm.org/git/llvm.git\n"
214" \t\t and\n"
215" \t\tgit clone http://llvm.org/git/clang.git\n\n"
216" \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
217" \tdebian/ubuntu:\n"
218" \t\thttp://llvm.org/apt\n\n"
219" \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
220" \toption in [llvm] section of ~/.perfconfig to:\n\n"
221" \t \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS $PERF_BPF_INC_OPTIONS \\\n"
222" \t -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
223" \t -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
224" \t(Replace /path/to/llc with path to your llc)\n\n"
225);
226}
227
228static int detect_kbuild_dir(char **kbuild_dir)
229{
230 const char *test_dir = llvm_param.kbuild_dir;
231 const char *prefix_dir = "";
232 const char *suffix_dir = "";
233
234 char *autoconf_path;
235
236 int err;
237
238 if (!test_dir) {
239
240 char release[128];
241
242 err = fetch_kernel_version(NULL, release,
243 sizeof(release));
244 if (err)
245 return -EINVAL;
246
247 test_dir = release;
248 prefix_dir = "/lib/modules/";
249 suffix_dir = "/build";
250 }
251
252 err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
253 prefix_dir, test_dir, suffix_dir);
254 if (err < 0)
255 return -ENOMEM;
256
257 if (access(autoconf_path, R_OK) == 0) {
258 free(autoconf_path);
259
260 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
261 suffix_dir);
262 if (err < 0)
263 return -ENOMEM;
264 return 0;
265 }
266 free(autoconf_path);
267 return -ENOENT;
268}
269
270static const char *kinc_fetch_script =
271"#!/usr/bin/env sh\n"
272"if ! test -d \"$KBUILD_DIR\"\n"
273"then\n"
274" exit 1\n"
275"fi\n"
276"if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
277"then\n"
278" exit 1\n"
279"fi\n"
280"TMPDIR=`mktemp -d`\n"
281"if test -z \"$TMPDIR\"\n"
282"then\n"
283" exit 1\n"
284"fi\n"
285"cat << EOF > $TMPDIR/Makefile\n"
286"obj-y := dummy.o\n"
287"\\$(obj)/%.o: \\$(src)/%.c\n"
288"\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
289"EOF\n"
290"touch $TMPDIR/dummy.c\n"
291"make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
292"RET=$?\n"
293"rm -rf $TMPDIR\n"
294"exit $RET\n";
295
296void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
297{
298 static char *saved_kbuild_dir;
299 static char *saved_kbuild_include_opts;
300 int err;
301
302 if (!kbuild_dir || !kbuild_include_opts)
303 return;
304
305 *kbuild_dir = NULL;
306 *kbuild_include_opts = NULL;
307
308 if (saved_kbuild_dir && saved_kbuild_include_opts &&
309 !IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
310 *kbuild_dir = strdup(saved_kbuild_dir);
311 *kbuild_include_opts = strdup(saved_kbuild_include_opts);
312
313 if (*kbuild_dir && *kbuild_include_opts)
314 return;
315
316 zfree(kbuild_dir);
317 zfree(kbuild_include_opts);
318
319
320
321
322
323 return;
324 }
325
326 if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
327 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
328 pr_debug("Skip kbuild options detection.\n");
329 goto errout;
330 }
331
332 err = detect_kbuild_dir(kbuild_dir);
333 if (err) {
334 pr_warning(
335"WARNING:\tunable to get correct kernel building directory.\n"
336"Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
337" \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
338" \tdetection.\n\n");
339 goto errout;
340 }
341
342 pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
343 force_set_env("KBUILD_DIR", *kbuild_dir);
344 force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
345 err = read_from_pipe(kinc_fetch_script,
346 (void **)kbuild_include_opts,
347 NULL);
348 if (err) {
349 pr_warning(
350"WARNING:\tunable to get kernel include directories from '%s'\n"
351"Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
352" \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
353" \toption in [llvm] to \"\" to suppress this detection.\n\n",
354 *kbuild_dir);
355
356 zfree(kbuild_dir);
357 goto errout;
358 }
359
360 pr_debug("include option is set to %s\n", *kbuild_include_opts);
361
362 saved_kbuild_dir = strdup(*kbuild_dir);
363 saved_kbuild_include_opts = strdup(*kbuild_include_opts);
364
365 if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
366 zfree(&saved_kbuild_dir);
367 zfree(&saved_kbuild_include_opts);
368 }
369 return;
370errout:
371 saved_kbuild_dir = ERR_PTR(-EINVAL);
372 saved_kbuild_include_opts = ERR_PTR(-EINVAL);
373}
374
375int llvm__get_nr_cpus(void)
376{
377 static int nr_cpus_avail = 0;
378 char serr[STRERR_BUFSIZE];
379
380 if (nr_cpus_avail > 0)
381 return nr_cpus_avail;
382
383 nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
384 if (nr_cpus_avail <= 0) {
385 pr_err(
386"WARNING:\tunable to get available CPUs in this system: %s\n"
387" \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
388 nr_cpus_avail = 128;
389 }
390 return nr_cpus_avail;
391}
392
393void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
394{
395 char *obj_path = strdup(path);
396 FILE *fp;
397 char *p;
398
399 if (!obj_path) {
400 pr_warning("WARNING: Not enough memory, skip object dumping\n");
401 return;
402 }
403
404 p = strrchr(obj_path, '.');
405 if (!p || (strcmp(p, ".c") != 0)) {
406 pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
407 obj_path);
408 goto out;
409 }
410
411 p[1] = 'o';
412 fp = fopen(obj_path, "wb");
413 if (!fp) {
414 pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
415 obj_path, strerror(errno));
416 goto out;
417 }
418
419 pr_info("LLVM: dumping %s\n", obj_path);
420 if (fwrite(obj_buf, size, 1, fp) != 1)
421 pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n",
422 obj_path, strerror(errno));
423 fclose(fp);
424out:
425 free(obj_path);
426}
427
428int llvm__compile_bpf(const char *path, void **p_obj_buf,
429 size_t *p_obj_buf_sz)
430{
431 size_t obj_buf_sz;
432 void *obj_buf = NULL;
433 int err, nr_cpus_avail;
434 unsigned int kernel_version;
435 char linux_version_code_str[64];
436 const char *clang_opt = llvm_param.clang_opt;
437 char clang_path[PATH_MAX], llc_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
438 char serr[STRERR_BUFSIZE];
439 char *kbuild_dir = NULL, *kbuild_include_opts = NULL,
440 *perf_bpf_include_opts = NULL;
441 const char *template = llvm_param.clang_bpf_cmd_template;
442 char *pipe_template = NULL;
443 const char *opts = llvm_param.opts;
444 char *command_echo = NULL, *command_out;
445 char *perf_include_dir = system_path(PERF_INCLUDE_DIR);
446
447 if (path[0] != '-' && realpath(path, abspath) == NULL) {
448 err = errno;
449 pr_err("ERROR: problems with path %s: %s\n",
450 path, str_error_r(err, serr, sizeof(serr)));
451 return -err;
452 }
453
454 if (!template)
455 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
456
457 err = search_program(llvm_param.clang_path,
458 "clang", clang_path);
459 if (err) {
460 pr_err(
461"ERROR:\tunable to find clang.\n"
462"Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
463" \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
464 version_notice();
465 return -ENOENT;
466 }
467
468
469
470
471
472 llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
473
474 nr_cpus_avail = llvm__get_nr_cpus();
475 snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
476 nr_cpus_avail);
477
478 if (fetch_kernel_version(&kernel_version, NULL, 0))
479 kernel_version = 0;
480
481 snprintf(linux_version_code_str, sizeof(linux_version_code_str),
482 "0x%x", kernel_version);
483 if (asprintf(&perf_bpf_include_opts, "-I%s/bpf", perf_include_dir) < 0)
484 goto errout;
485 force_set_env("NR_CPUS", nr_cpus_avail_str);
486 force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
487 force_set_env("CLANG_EXEC", clang_path);
488 force_set_env("CLANG_OPTIONS", clang_opt);
489 force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);
490 force_set_env("PERF_BPF_INC_OPTIONS", perf_bpf_include_opts);
491 force_set_env("WORKING_DIR", kbuild_dir ? : ".");
492
493 if (opts) {
494 err = search_program(llvm_param.llc_path, "llc", llc_path);
495 if (err) {
496 pr_err("ERROR:\tunable to find llc.\n"
497 "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
498 " \tand 'llc-path' option in [llvm] section of ~/.perfconfig.\n");
499 version_notice();
500 goto errout;
501 }
502
503 if (asprintf(&pipe_template, "%s -emit-llvm | %s -march=bpf %s -filetype=obj -o -",
504 template, llc_path, opts) < 0) {
505 pr_err("ERROR:\tnot enough memory to setup command line\n");
506 goto errout;
507 }
508
509 template = pipe_template;
510
511 }
512
513
514
515
516
517
518 force_set_env("CLANG_SOURCE",
519 (path[0] == '-') ? path : abspath);
520
521 pr_debug("llvm compiling command template: %s\n", template);
522
523 if (asprintf(&command_echo, "echo -n \"%s\"", template) < 0)
524 goto errout;
525
526 err = read_from_pipe(command_echo, (void **) &command_out, NULL);
527 if (err)
528 goto errout;
529
530 pr_debug("llvm compiling command : %s\n", command_out);
531
532 err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
533 if (err) {
534 pr_err("ERROR:\tunable to compile %s\n", path);
535 pr_err("Hint:\tCheck error message shown above.\n");
536 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
537 pr_err(" \t\tclang -target bpf -O2 -c %s\n", path);
538 pr_err(" \twith proper -I and -D options.\n");
539 goto errout;
540 }
541
542 free(command_echo);
543 free(command_out);
544 free(kbuild_dir);
545 free(kbuild_include_opts);
546 free(perf_bpf_include_opts);
547 free(perf_include_dir);
548
549 if (!p_obj_buf)
550 free(obj_buf);
551 else
552 *p_obj_buf = obj_buf;
553
554 if (p_obj_buf_sz)
555 *p_obj_buf_sz = obj_buf_sz;
556 return 0;
557errout:
558 free(command_echo);
559 free(kbuild_dir);
560 free(kbuild_include_opts);
561 free(obj_buf);
562 free(perf_bpf_include_opts);
563 free(perf_include_dir);
564 free(pipe_template);
565 if (p_obj_buf)
566 *p_obj_buf = NULL;
567 if (p_obj_buf_sz)
568 *p_obj_buf_sz = 0;
569 return err;
570}
571
572int llvm__search_clang(void)
573{
574 char clang_path[PATH_MAX];
575
576 return search_program(llvm_param.clang_path, "clang", clang_path);
577}
578
