tools/perf/util/llvm-utils.c

   1 /*
   2  * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
   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
  16 #define CLANG_BPF_CMD_DEFAULT_TEMPLATE                          \
  17                 "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
  18                 "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE "     \
  19                 "$CLANG_OPTIONS $KERNEL_INC_OPTIONS "           \
  20                 "-Wno-unused-value -Wno-pointer-sign "          \
  21                 "-working-directory $WORKING_DIR "              \
  22                 "-c \"$CLANG_SOURCE\" -target bpf -O2 -o -"
  23
  24 struct llvm_param llvm_param = {
  25         .clang_path = "clang",
  26         .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
  27         .clang_opt = NULL,
  28         .kbuild_dir = NULL,
  29         .kbuild_opts = NULL,
  30         .user_set_param = false,
  31 };
  32
  33 int perf_llvm_config(const char *var, const char *value)
  34 {
  35         if (prefixcmp(var, "llvm."))
  36                 return 0;
  37         var += sizeof("llvm.") - 1;
  38
  39         if (!strcmp(var, "clang-path"))
  40                 llvm_param.clang_path = strdup(value);
  41         else if (!strcmp(var, "clang-bpf-cmd-template"))
  42                 llvm_param.clang_bpf_cmd_template = strdup(value);
  43         else if (!strcmp(var, "clang-opt"))
  44                 llvm_param.clang_opt = strdup(value);
  45         else if (!strcmp(var, "kbuild-dir"))
  46                 llvm_param.kbuild_dir = strdup(value);
  47         else if (!strcmp(var, "kbuild-opts"))
  48                 llvm_param.kbuild_opts = strdup(value);
  49         else if (!strcmp(var, "dump-obj"))
  50                 llvm_param.dump_obj = !!perf_config_bool(var, value);
  51         else {
  52                 pr_debug("Invalid LLVM config option: %s\n", value);
  53                 return -1;
  54         }
  55         llvm_param.user_set_param = true;
  56         return 0;
  57 }
  58
  59 static int
  60 search_program(const char *def, const char *name,
  61                char *output)
  62 {
  63         char *env, *path, *tmp = NULL;
  64         char buf[PATH_MAX];
  65         int ret;
  66
  67         output[0] = '\0';
  68         if (def && def[0] != '\0') {
  69                 if (def[0] == '/') {
  70                         if (access(def, F_OK) == 0) {
  71                                 strlcpy(output, def, PATH_MAX);
  72                                 return 0;
  73                         }
  74                 } else if (def[0] != '\0')
  75                         name = def;
  76         }
  77
  78         env = getenv("PATH");
  79         if (!env)
  80                 return -1;
  81         env = strdup(env);
  82         if (!env)
  83                 return -1;
  84
  85         ret = -ENOENT;
  86         path = strtok_r(env, ":",  &tmp);
  87         while (path) {
  88                 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
  89                 if (access(buf, F_OK) == 0) {
  90                         strlcpy(output, buf, PATH_MAX);
  91                         ret = 0;
  92                         break;
  93                 }
  94                 path = strtok_r(NULL, ":", &tmp);
  95         }
  96
  97         free(env);
  98         return ret;
  99 }
 100
 101 #define READ_SIZE       4096
 102 static int
 103 read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
 104 {
 105         int err = 0;
 106         void *buf = NULL;
 107         FILE *file = NULL;
 108         size_t read_sz = 0, buf_sz = 0;
 109         char serr[STRERR_BUFSIZE];
 110
 111         file = popen(cmd, "r");
 112         if (!file) {
 113                 pr_err("ERROR: unable to popen cmd: %s\n",
 114                        str_error_r(errno, serr, sizeof(serr)));
 115                 return -EINVAL;
 116         }
 117
 118         while (!feof(file) && !ferror(file)) {
 119                 /*
 120                  * Make buf_sz always have obe byte extra space so we
 121                  * can put '\0' there.
 122                  */
 123                 if (buf_sz - read_sz < READ_SIZE + 1) {
 124                         void *new_buf;
 125
 126                         buf_sz = read_sz + READ_SIZE + 1;
 127                         new_buf = realloc(buf, buf_sz);
 128
 129                         if (!new_buf) {
 130                                 pr_err("ERROR: failed to realloc memory\n");
 131                                 err = -ENOMEM;
 132                                 goto errout;
 133                         }
 134
 135                         buf = new_buf;
 136                 }
 137                 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
 138         }
 139
 140         if (buf_sz - read_sz < 1) {
 141                 pr_err("ERROR: internal error\n");
 142                 err = -EINVAL;
 143                 goto errout;
 144         }
 145
 146         if (ferror(file)) {
 147                 pr_err("ERROR: error occurred when reading from pipe: %s\n",
 148                        str_error_r(errno, serr, sizeof(serr)));
 149                 err = -EIO;
 150                 goto errout;
 151         }
 152
 153         err = WEXITSTATUS(pclose(file));
 154         file = NULL;
 155         if (err) {
 156                 err = -EINVAL;
 157                 goto errout;
 158         }
 159
 160         /*
 161          * If buf is string, give it terminal '\0' to make our life
 162          * easier. If buf is not string, that '\0' is out of space
 163          * indicated by read_sz so caller won't even notice it.
 164          */
 165         ((char *)buf)[read_sz] = '\0';
 166
 167         if (!p_buf)
 168                 free(buf);
 169         else
 170                 *p_buf = buf;
 171
 172         if (p_read_sz)
 173                 *p_read_sz = read_sz;
 174         return 0;
 175
 176 errout:
 177         if (file)
 178                 pclose(file);
 179         free(buf);
 180         if (p_buf)
 181                 *p_buf = NULL;
 182         if (p_read_sz)
 183                 *p_read_sz = 0;
 184         return err;
 185 }
 186
 187 static inline void
 188 force_set_env(const char *var, const char *value)
 189 {
 190         if (value) {
 191                 setenv(var, value, 1);
 192                 pr_debug("set env: %s=%s\n", var, value);
 193         } else {
 194                 unsetenv(var);
 195                 pr_debug("unset env: %s\n", var);
 196         }
 197 }
 198
 199 static void
 200 version_notice(void)
 201 {
 202         pr_err(
 203 "     \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
 204 "     \tYou may want to try git trunk:\n"
 205 "     \t\tgit clone http://llvm.org/git/llvm.git\n"
 206 "     \t\t     and\n"
 207 "     \t\tgit clone http://llvm.org/git/clang.git\n\n"
 208 "     \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
 209 "     \tdebian/ubuntu:\n"
 210 "     \t\thttp://llvm.org/apt\n\n"
 211 "     \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
 212 "     \toption in [llvm] section of ~/.perfconfig to:\n\n"
 213 "     \t  \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS \\\n"
 214 "     \t     -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
 215 "     \t     -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
 216 "     \t(Replace /path/to/llc with path to your llc)\n\n"
 217 );
 218 }
 219
 220 static int detect_kbuild_dir(char **kbuild_dir)
 221 {
 222         const char *test_dir = llvm_param.kbuild_dir;
 223         const char *prefix_dir = "";
 224         const char *suffix_dir = "";
 225
 226         char *autoconf_path;
 227
 228         int err;
 229
 230         if (!test_dir) {
 231                 /* _UTSNAME_LENGTH is 65 */
 232                 char release[128];
 233
 234                 err = fetch_kernel_version(NULL, release,
 235                                            sizeof(release));
 236                 if (err)
 237                         return -EINVAL;
 238
 239                 test_dir = release;
 240                 prefix_dir = "/lib/modules/";
 241                 suffix_dir = "/build";
 242         }
 243
 244         err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
 245                        prefix_dir, test_dir, suffix_dir);
 246         if (err < 0)
 247                 return -ENOMEM;
 248
 249         if (access(autoconf_path, R_OK) == 0) {
 250                 free(autoconf_path);
 251
 252                 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
 253                                suffix_dir);
 254                 if (err < 0)
 255                         return -ENOMEM;
 256                 return 0;
 257         }
 258         free(autoconf_path);
 259         return -ENOENT;
 260 }
 261
 262 static const char *kinc_fetch_script =
 263 "#!/usr/bin/env sh\n"
 264 "if ! test -d \"$KBUILD_DIR\"\n"
 265 "then\n"
 266 "       exit -1\n"
 267 "fi\n"
 268 "if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
 269 "then\n"
 270 "       exit -1\n"
 271 "fi\n"
 272 "TMPDIR=`mktemp -d`\n"
 273 "if test -z \"$TMPDIR\"\n"
 274 "then\n"
 275 "    exit -1\n"
 276 "fi\n"
 277 "cat << EOF > $TMPDIR/Makefile\n"
 278 "obj-y := dummy.o\n"
 279 "\\$(obj)/%.o: \\$(src)/%.c\n"
 280 "\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
 281 "EOF\n"
 282 "touch $TMPDIR/dummy.c\n"
 283 "make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
 284 "RET=$?\n"
 285 "rm -rf $TMPDIR\n"
 286 "exit $RET\n";
 287
 288 void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
 289 {
 290         static char *saved_kbuild_dir;
 291         static char *saved_kbuild_include_opts;
 292         int err;
 293
 294         if (!kbuild_dir || !kbuild_include_opts)
 295                 return;
 296
 297         *kbuild_dir = NULL;
 298         *kbuild_include_opts = NULL;
 299
 300         if (saved_kbuild_dir && saved_kbuild_include_opts &&
 301             !IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
 302                 *kbuild_dir = strdup(saved_kbuild_dir);
 303                 *kbuild_include_opts = strdup(saved_kbuild_include_opts);
 304
 305                 if (*kbuild_dir && *kbuild_include_opts)
 306                         return;
 307
 308                 zfree(kbuild_dir);
 309                 zfree(kbuild_include_opts);
 310                 /*
 311                  * Don't fall through: it may breaks saved_kbuild_dir and
 312                  * saved_kbuild_include_opts if detect them again when
 313                  * memory is low.
 314                  */
 315                 return;
 316         }
 317
 318         if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
 319                 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
 320                 pr_debug("Skip kbuild options detection.\n");
 321                 goto errout;
 322         }
 323
 324         err = detect_kbuild_dir(kbuild_dir);
 325         if (err) {
 326                 pr_warning(
 327 "WARNING:\tunable to get correct kernel building directory.\n"
 328 "Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
 329 "     \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
 330 "     \tdetection.\n\n");
 331                 goto errout;
 332         }
 333
 334         pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
 335         force_set_env("KBUILD_DIR", *kbuild_dir);
 336         force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
 337         err = read_from_pipe(kinc_fetch_script,
 338                              (void **)kbuild_include_opts,
 339                              NULL);
 340         if (err) {
 341                 pr_warning(
 342 "WARNING:\tunable to get kernel include directories from '%s'\n"
 343 "Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
 344 "     \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
 345 "     \toption in [llvm] to \"\" to suppress this detection.\n\n",
 346                         *kbuild_dir);
 347
 348                 free(*kbuild_dir);
 349                 *kbuild_dir = NULL;
 350                 goto errout;
 351         }
 352
 353         pr_debug("include option is set to %s\n", *kbuild_include_opts);
 354
 355         saved_kbuild_dir = strdup(*kbuild_dir);
 356         saved_kbuild_include_opts = strdup(*kbuild_include_opts);
 357
 358         if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
 359                 zfree(&saved_kbuild_dir);
 360                 zfree(&saved_kbuild_include_opts);
 361         }
 362         return;
 363 errout:
 364         saved_kbuild_dir = ERR_PTR(-EINVAL);
 365         saved_kbuild_include_opts = ERR_PTR(-EINVAL);
 366 }
 367
 368 int llvm__get_nr_cpus(void)
 369 {
 370         static int nr_cpus_avail = 0;
 371         char serr[STRERR_BUFSIZE];
 372
 373         if (nr_cpus_avail > 0)
 374                 return nr_cpus_avail;
 375
 376         nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
 377         if (nr_cpus_avail <= 0) {
 378                 pr_err(
 379 "WARNING:\tunable to get available CPUs in this system: %s\n"
 380 "        \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
 381                 nr_cpus_avail = 128;
 382         }
 383         return nr_cpus_avail;
 384 }
 385
 386 void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
 387 {
 388         char *obj_path = strdup(path);
 389         FILE *fp;
 390         char *p;
 391
 392         if (!obj_path) {
 393                 pr_warning("WARNING: Not enough memory, skip object dumping\n");
 394                 return;
 395         }
 396
 397         p = strrchr(obj_path, '.');
 398         if (!p || (strcmp(p, ".c") != 0)) {
 399                 pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
 400                            obj_path);
 401                 goto out;
 402         }
 403
 404         p[1] = 'o';
 405         fp = fopen(obj_path, "wb");
 406         if (!fp) {
 407                 pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
 408                            obj_path, strerror(errno));
 409                 goto out;
 410         }
 411
 412         pr_info("LLVM: dumping %s\n", obj_path);
 413         if (fwrite(obj_buf, size, 1, fp) != 1)
 414                 pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n",
 415                            obj_path, strerror(errno));
 416         fclose(fp);
 417 out:
 418         free(obj_path);
 419 }
 420
 421 int llvm__compile_bpf(const char *path, void **p_obj_buf,
 422                       size_t *p_obj_buf_sz)
 423 {
 424         size_t obj_buf_sz;
 425         void *obj_buf = NULL;
 426         int err, nr_cpus_avail;
 427         unsigned int kernel_version;
 428         char linux_version_code_str[64];
 429         const char *clang_opt = llvm_param.clang_opt;
 430         char clang_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
 431         char serr[STRERR_BUFSIZE];
 432         char *kbuild_dir = NULL, *kbuild_include_opts = NULL;
 433         const char *template = llvm_param.clang_bpf_cmd_template;
 434
 435         if (path[0] != '-' && realpath(path, abspath) == NULL) {
 436                 err = errno;
 437                 pr_err("ERROR: problems with path %s: %s\n",
 438                        path, str_error_r(err, serr, sizeof(serr)));
 439                 return -err;
 440         }
 441
 442         if (!template)
 443                 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
 444
 445         err = search_program(llvm_param.clang_path,
 446                              "clang", clang_path);
 447         if (err) {
 448                 pr_err(
 449 "ERROR:\tunable to find clang.\n"
 450 "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
 451 "     \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
 452                 version_notice();
 453                 return -ENOENT;
 454         }
 455
 456         /*
 457          * This is an optional work. Even it fail we can continue our
 458          * work. Needn't to check error return.
 459          */
 460         llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
 461
 462         nr_cpus_avail = llvm__get_nr_cpus();
 463         snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
 464                  nr_cpus_avail);
 465
 466         if (fetch_kernel_version(&kernel_version, NULL, 0))
 467                 kernel_version = 0;
 468
 469         snprintf(linux_version_code_str, sizeof(linux_version_code_str),
 470                  "0x%x", kernel_version);
 471
 472         force_set_env("NR_CPUS", nr_cpus_avail_str);
 473         force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
 474         force_set_env("CLANG_EXEC", clang_path);
 475         force_set_env("CLANG_OPTIONS", clang_opt);
 476         force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);
 477         force_set_env("WORKING_DIR", kbuild_dir ? : ".");
 478
 479         /*
 480          * Since we may reset clang's working dir, path of source file
 481          * should be transferred into absolute path, except we want
 482          * stdin to be source file (testing).
 483          */
 484         force_set_env("CLANG_SOURCE",
 485                       (path[0] == '-') ? path : abspath);
 486
 487         pr_debug("llvm compiling command template: %s\n", template);
 488         err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
 489         if (err) {
 490                 pr_err("ERROR:\tunable to compile %s\n", path);
 491                 pr_err("Hint:\tCheck error message shown above.\n");
 492                 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
 493                 pr_err("     \t\tclang -target bpf -O2 -c %s\n", path);
 494                 pr_err("     \twith proper -I and -D options.\n");
 495                 goto errout;
 496         }
 497
 498         free(kbuild_dir);
 499         free(kbuild_include_opts);
 500
 501         if (!p_obj_buf)
 502                 free(obj_buf);
 503         else
 504                 *p_obj_buf = obj_buf;
 505
 506         if (p_obj_buf_sz)
 507                 *p_obj_buf_sz = obj_buf_sz;
 508         return 0;
 509 errout:
 510         free(kbuild_dir);
 511         free(kbuild_include_opts);
 512         free(obj_buf);
 513         if (p_obj_buf)
 514                 *p_obj_buf = NULL;
 515         if (p_obj_buf_sz)
 516                 *p_obj_buf_sz = 0;
 517         return err;
 518 }
 519
 520 int llvm__search_clang(void)
 521 {
 522         char clang_path[PATH_MAX];
 523
 524         return search_program(llvm_param.clang_path, "clang", clang_path);
 525 }