tools/perf/util/llvm-utils.c

   1 /*
   2  * Copyright (C) 2015, Wang Nan <[email protected]>
   3  * Copyright (C) 2015, Huawei Inc.
   4  */
   5
   6 #include <errno.h>
   7 #include <limits.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <linux/err.h>
  11 #include "debug.h"
  12 #include "llvm-utils.h"
  13 #include "config.h"
  14 #include "util.h"
  15 #include <sys/wait.h>
  16
  17 #define CLANG_BPF_CMD_DEFAULT_TEMPLATE                          \
  18                 "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
  19                 "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE "     \
  20                 "$CLANG_OPTIONS $KERNEL_INC_OPTIONS "           \
  21                 "-Wno-unused-value -Wno-pointer-sign "          \
  22                 "-working-directory $WORKING_DIR "              \
  23                 "-c \"$CLANG_SOURCE\" -target bpf -O2 -o -"
  24
  25 struct llvm_param llvm_param = {
  26         .clang_path = "clang",
  27         .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
  28         .clang_opt = NULL,
  29         .kbuild_dir = NULL,
  30         .kbuild_opts = NULL,
  31         .user_set_param = false,
  32 };
  33
  34 int perf_llvm_config(const char *var, const char *value)
  35 {
  36         if (prefixcmp(var, "llvm."))
  37                 return 0;
  38         var += sizeof("llvm.") - 1;
  39
  40         if (!strcmp(var, "clang-path"))
  41                 llvm_param.clang_path = strdup(value);
  42         else if (!strcmp(var, "clang-bpf-cmd-template"))
  43                 llvm_param.clang_bpf_cmd_template = strdup(value);
  44         else if (!strcmp(var, "clang-opt"))
  45                 llvm_param.clang_opt = strdup(value);
  46         else if (!strcmp(var, "kbuild-dir"))
  47                 llvm_param.kbuild_dir = strdup(value);
  48         else if (!strcmp(var, "kbuild-opts"))
  49                 llvm_param.kbuild_opts = strdup(value);
  50         else if (!strcmp(var, "dump-obj"))
  51                 llvm_param.dump_obj = !!perf_config_bool(var, value);
  52         else {
  53                 pr_debug("Invalid LLVM config option: %s\n", value);
  54                 return -1;
  55         }
  56         llvm_param.user_set_param = true;
  57         return 0;
  58 }
  59
  60 static int
  61 search_program(const char *def, const char *name,
  62                char *output)
  63 {
  64         char *env, *path, *tmp = NULL;
  65         char buf[PATH_MAX];
  66         int ret;
  67
  68         output[0] = '\0';
  69         if (def && def[0] != '\0') {
  70                 if (def[0] == '/') {
  71                         if (access(def, F_OK) == 0) {
  72                                 strlcpy(output, def, PATH_MAX);
  73                                 return 0;
  74                         }
  75                 } else if (def[0] != '\0')
  76                         name = def;
  77         }
  78
  79         env = getenv("PATH");
  80         if (!env)
  81                 return -1;
  82         env = strdup(env);
  83         if (!env)
  84                 return -1;
  85
  86         ret = -ENOENT;
  87         path = strtok_r(env, ":",  &tmp);
  88         while (path) {
  89                 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
  90                 if (access(buf, F_OK) == 0) {
  91                         strlcpy(output, buf, PATH_MAX);
  92                         ret = 0;
  93                         break;
  94                 }
  95                 path = strtok_r(NULL, ":", &tmp);
  96         }
  97
  98         free(env);
  99         return ret;
 100 }
 101
 102 #define READ_SIZE       4096
 103 static int
 104 read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
 105 {
 106         int err = 0;
 107         void *buf = NULL;
 108         FILE *file = NULL;
 109         size_t read_sz = 0, buf_sz = 0;
 110         char serr[STRERR_BUFSIZE];
 111
 112         file = popen(cmd, "r");
 113         if (!file) {
 114                 pr_err("ERROR: unable to popen cmd: %s\n",
 115                        str_error_r(errno, serr, sizeof(serr)));
 116                 return -EINVAL;
 117         }
 118
 119         while (!feof(file) && !ferror(file)) {
 120                 /*
 121                  * Make buf_sz always have obe byte extra space so we
 122                  * can put '\0' there.
 123                  */
 124                 if (buf_sz - read_sz < READ_SIZE + 1) {
 125                         void *new_buf;
 126
 127                         buf_sz = read_sz + READ_SIZE + 1;
 128                         new_buf = realloc(buf, buf_sz);
 129
 130                         if (!new_buf) {
 131                                 pr_err("ERROR: failed to realloc memory\n");
 132                                 err = -ENOMEM;
 133                                 goto errout;
 134                         }
 135
 136                         buf = new_buf;
 137                 }
 138                 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
 139         }
 140
 141         if (buf_sz - read_sz < 1) {
 142                 pr_err("ERROR: internal error\n");
 143                 err = -EINVAL;
 144                 goto errout;
 145         }
 146
 147         if (ferror(file)) {
 148                 pr_err("ERROR: error occurred when reading from pipe: %s\n",
 149                        str_error_r(errno, serr, sizeof(serr)));
 150                 err = -EIO;
 151                 goto errout;
 152         }
 153
 154         err = WEXITSTATUS(pclose(file));
 155         file = NULL;
 156         if (err) {
 157                 err = -EINVAL;
 158                 goto errout;
 159         }
 160
 161         /*
 162          * If buf is string, give it terminal '\0' to make our life
 163          * easier. If buf is not string, that '\0' is out of space
 164          * indicated by read_sz so caller won't even notice it.
 165          */
 166         ((char *)buf)[read_sz] = '\0';
 167
 168         if (!p_buf)
 169                 free(buf);
 170         else
 171                 *p_buf = buf;
 172
 173         if (p_read_sz)
 174                 *p_read_sz = read_sz;
 175         return 0;
 176
 177 errout:
 178         if (file)
 179                 pclose(file);
 180         free(buf);
 181         if (p_buf)
 182                 *p_buf = NULL;
 183         if (p_read_sz)
 184                 *p_read_sz = 0;
 185         return err;
 186 }
 187
 188 static inline void
 189 force_set_env(const char *var, const char *value)
 190 {
 191         if (value) {
 192                 setenv(var, value, 1);
 193                 pr_debug("set env: %s=%s\n", var, value);
 194         } else {
 195                 unsetenv(var);
 196                 pr_debug("unset env: %s\n", var);
 197         }
 198 }
 199
 200 static void
 201 version_notice(void)
 202 {
 203         pr_err(
 204 "     \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
 205 "     \tYou may want to try git trunk:\n"
 206 "     \t\tgit clone http://llvm.org/git/llvm.git\n"
 207 "     \t\t     and\n"
 208 "     \t\tgit clone http://llvm.org/git/clang.git\n\n"
 209 "     \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
 210 "     \tdebian/ubuntu:\n"
 211 "     \t\thttp://llvm.org/apt\n\n"
 212 "     \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
 213 "     \toption in [llvm] section of ~/.perfconfig to:\n\n"
 214 "     \t  \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS \\\n"
 215 "     \t     -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
 216 "     \t     -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
 217 "     \t(Replace /path/to/llc with path to your llc)\n\n"
 218 );
 219 }
 220
 221 static int detect_kbuild_dir(char **kbuild_dir)
 222 {
 223         const char *test_dir = llvm_param.kbuild_dir;
 224         const char *prefix_dir = "";
 225         const char *suffix_dir = "";
 226
 227         char *autoconf_path;
 228
 229         int err;
 230
 231         if (!test_dir) {
 232                 /* _UTSNAME_LENGTH is 65 */
 233                 char release[128];
 234
 235                 err = fetch_kernel_version(NULL, release,
 236                                            sizeof(release));
 237                 if (err)
 238                         return -EINVAL;
 239
 240                 test_dir = release;
 241                 prefix_dir = "/lib/modules/";
 242                 suffix_dir = "/build";
 243         }
 244
 245         err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
 246                        prefix_dir, test_dir, suffix_dir);
 247         if (err < 0)
 248                 return -ENOMEM;
 249
 250         if (access(autoconf_path, R_OK) == 0) {
 251                 free(autoconf_path);
 252
 253                 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
 254                                suffix_dir);
 255                 if (err < 0)
 256                         return -ENOMEM;
 257                 return 0;
 258         }
 259         free(autoconf_path);
 260         return -ENOENT;
 261 }
 262
 263 static const char *kinc_fetch_script =
 264 "#!/usr/bin/env sh\n"
 265 "if ! test -d \"$KBUILD_DIR\"\n"
 266 "then\n"
 267 "       exit -1\n"
 268 "fi\n"
 269 "if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
 270 "then\n"
 271 "       exit -1\n"
 272 "fi\n"
 273 "TMPDIR=`mktemp -d`\n"
 274 "if test -z \"$TMPDIR\"\n"
 275 "then\n"
 276 "    exit -1\n"
 277 "fi\n"
 278 "cat << EOF > $TMPDIR/Makefile\n"
 279 "obj-y := dummy.o\n"
 280 "\\$(obj)/%.o: \\$(src)/%.c\n"
 281 "\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
 282 "EOF\n"
 283 "touch $TMPDIR/dummy.c\n"
 284 "make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
 285 "RET=$?\n"
 286 "rm -rf $TMPDIR\n"
 287 "exit $RET\n";
 288
 289 void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
 290 {
 291         static char *saved_kbuild_dir;
 292         static char *saved_kbuild_include_opts;
 293         int err;
 294
 295         if (!kbuild_dir || !kbuild_include_opts)
 296                 return;
 297
 298         *kbuild_dir = NULL;
 299         *kbuild_include_opts = NULL;
 300
 301         if (saved_kbuild_dir && saved_kbuild_include_opts &&
 302             !IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
 303                 *kbuild_dir = strdup(saved_kbuild_dir);
 304                 *kbuild_include_opts = strdup(saved_kbuild_include_opts);
 305
 306                 if (*kbuild_dir && *kbuild_include_opts)
 307                         return;
 308
 309                 zfree(kbuild_dir);
 310                 zfree(kbuild_include_opts);
 311                 /*
 312                  * Don't fall through: it may breaks saved_kbuild_dir and
 313                  * saved_kbuild_include_opts if detect them again when
 314                  * memory is low.
 315                  */
 316                 return;
 317         }
 318
 319         if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
 320                 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
 321                 pr_debug("Skip kbuild options detection.\n");
 322                 goto errout;
 323         }
 324
 325         err = detect_kbuild_dir(kbuild_dir);
 326         if (err) {
 327                 pr_warning(
 328 "WARNING:\tunable to get correct kernel building directory.\n"
 329 "Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
 330 "     \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
 331 "     \tdetection.\n\n");
 332                 goto errout;
 333         }
 334
 335         pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
 336         force_set_env("KBUILD_DIR", *kbuild_dir);
 337         force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
 338         err = read_from_pipe(kinc_fetch_script,
 339                              (void **)kbuild_include_opts,
 340                              NULL);
 341         if (err) {
 342                 pr_warning(
 343 "WARNING:\tunable to get kernel include directories from '%s'\n"
 344 "Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
 345 "     \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
 346 "     \toption in [llvm] to \"\" to suppress this detection.\n\n",
 347                         *kbuild_dir);
 348
 349                 free(*kbuild_dir);
 350                 *kbuild_dir = NULL;
 351                 goto errout;
 352         }
 353
 354         pr_debug("include option is set to %s\n", *kbuild_include_opts);
 355
 356         saved_kbuild_dir = strdup(*kbuild_dir);
 357         saved_kbuild_include_opts = strdup(*kbuild_include_opts);
 358
 359         if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
 360                 zfree(&saved_kbuild_dir);
 361                 zfree(&saved_kbuild_include_opts);
 362         }
 363         return;
 364 errout:
 365         saved_kbuild_dir = ERR_PTR(-EINVAL);
 366         saved_kbuild_include_opts = ERR_PTR(-EINVAL);
 367 }
 368
 369 int llvm__get_nr_cpus(void)
 370 {
 371         static int nr_cpus_avail = 0;
 372         char serr[STRERR_BUFSIZE];
 373
 374         if (nr_cpus_avail > 0)
 375                 return nr_cpus_avail;
 376
 377         nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
 378         if (nr_cpus_avail <= 0) {
 379                 pr_err(
 380 "WARNING:\tunable to get available CPUs in this system: %s\n"
 381 "        \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
 382                 nr_cpus_avail = 128;
 383         }
 384         return nr_cpus_avail;
 385 }
 386
 387 void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
 388 {
 389         char *obj_path = strdup(path);
 390         FILE *fp;
 391         char *p;
 392
 393         if (!obj_path) {
 394                 pr_warning("WARNING: Not enough memory, skip object dumping\n");
 395                 return;
 396         }
 397
 398         p = strrchr(obj_path, '.');
 399         if (!p || (strcmp(p, ".c") != 0)) {
 400                 pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
 401                            obj_path);
 402                 goto out;
 403         }
 404
 405         p[1] = 'o';
 406         fp = fopen(obj_path, "wb");
 407         if (!fp) {
 408                 pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
 409                            obj_path, strerror(errno));
 410                 goto out;
 411         }
 412
 413         pr_info("LLVM: dumping %s\n", obj_path);
 414         if (fwrite(obj_buf, size, 1, fp) != 1)
 415                 pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n",
 416                            obj_path, strerror(errno));
 417         fclose(fp);
 418 out:
 419         free(obj_path);
 420 }
 421
 422 int llvm__compile_bpf(const char *path, void **p_obj_buf,
 423                       size_t *p_obj_buf_sz)
 424 {
 425         size_t obj_buf_sz;
 426         void *obj_buf = NULL;
 427         int err, nr_cpus_avail;
 428         unsigned int kernel_version;
 429         char linux_version_code_str[64];
 430         const char *clang_opt = llvm_param.clang_opt;
 431         char clang_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
 432         char serr[STRERR_BUFSIZE];
 433         char *kbuild_dir = NULL, *kbuild_include_opts = NULL;
 434         const char *template = llvm_param.clang_bpf_cmd_template;
 435
 436         if (path[0] != '-' && realpath(path, abspath) == NULL) {
 437                 err = errno;
 438                 pr_err("ERROR: problems with path %s: %s\n",
 439                        path, str_error_r(err, serr, sizeof(serr)));
 440                 return -err;
 441         }
 442
 443         if (!template)
 444                 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
 445
 446         err = search_program(llvm_param.clang_path,
 447                              "clang", clang_path);
 448         if (err) {
 449                 pr_err(
 450 "ERROR:\tunable to find clang.\n"
 451 "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
 452 "     \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
 453                 version_notice();
 454                 return -ENOENT;
 455         }
 456
 457         /*
 458          * This is an optional work. Even it fail we can continue our
 459          * work. Needn't to check error return.
 460          */
 461         llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
 462
 463         nr_cpus_avail = llvm__get_nr_cpus();
 464         snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
 465                  nr_cpus_avail);
 466
 467         if (fetch_kernel_version(&kernel_version, NULL, 0))
 468                 kernel_version = 0;
 469
 470         snprintf(linux_version_code_str, sizeof(linux_version_code_str),
 471                  "0x%x", kernel_version);
 472
 473         force_set_env("NR_CPUS", nr_cpus_avail_str);
 474         force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
 475         force_set_env("CLANG_EXEC", clang_path);
 476         force_set_env("CLANG_OPTIONS", clang_opt);
 477         force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);
 478         force_set_env("WORKING_DIR", kbuild_dir ? : ".");
 479
 480         /*
 481          * Since we may reset clang's working dir, path of source file
 482          * should be transferred into absolute path, except we want
 483          * stdin to be source file (testing).
 484          */
 485         force_set_env("CLANG_SOURCE",
 486                       (path[0] == '-') ? path : abspath);
 487
 488         pr_debug("llvm compiling command template: %s\n", template);
 489         err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
 490         if (err) {
 491                 pr_err("ERROR:\tunable to compile %s\n", path);
 492                 pr_err("Hint:\tCheck error message shown above.\n");
 493                 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
 494                 pr_err("     \t\tclang -target bpf -O2 -c %s\n", path);
 495                 pr_err("     \twith proper -I and -D options.\n");
 496                 goto errout;
 497         }
 498
 499         free(kbuild_dir);
 500         free(kbuild_include_opts);
 501
 502         if (!p_obj_buf)
 503                 free(obj_buf);
 504         else
 505                 *p_obj_buf = obj_buf;
 506
 507         if (p_obj_buf_sz)
 508                 *p_obj_buf_sz = obj_buf_sz;
 509         return 0;
 510 errout:
 511         free(kbuild_dir);
 512         free(kbuild_include_opts);
 513         free(obj_buf);
 514         if (p_obj_buf)
 515                 *p_obj_buf = NULL;
 516         if (p_obj_buf_sz)
 517                 *p_obj_buf_sz = 0;
 518         return err;
 519 }
 520
 521 int llvm__search_clang(void)
 522 {
 523         char clang_path[PATH_MAX];
 524
 525         return search_program(llvm_param.clang_path, "clang", clang_path);
 526 }