tools/perf/util/llvm-utils.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2015, Wang Nan <wangnan0@huawei.com>
   4  * Copyright (C) 2015, Huawei Inc.
   5  */
   6
   7 #include <errno.h>
   8 #include <limits.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <linux/err.h>
  12 #include "debug.h"
  13 #include "llvm-utils.h"
  14 #include "config.h"
  15 #include "util.h"
  16 #include <sys/wait.h>
  17
  18 #define CLANG_BPF_CMD_DEFAULT_TEMPLATE                          \
  19                 "$CLANG_EXEC -D__KERNEL__ -D__NR_CPUS__=$NR_CPUS "\
  20                 "-DLINUX_VERSION_CODE=$LINUX_VERSION_CODE "     \
  21                 "$CLANG_OPTIONS $KERNEL_INC_OPTIONS "           \
  22                 "-Wno-unused-value -Wno-pointer-sign "          \
  23                 "-working-directory $WORKING_DIR "              \
  24                 "-c \"$CLANG_SOURCE\" -target bpf -O2 -o -"
  25
  26 struct llvm_param llvm_param = {
  27         .clang_path = "clang",
  28         .clang_bpf_cmd_template = CLANG_BPF_CMD_DEFAULT_TEMPLATE,
  29         .clang_opt = NULL,
  30         .kbuild_dir = NULL,
  31         .kbuild_opts = NULL,
  32         .user_set_param = false,
  33 };
  34
  35 int perf_llvm_config(const char *var, const char *value)
  36 {
  37         if (!strstarts(var, "llvm."))
  38                 return 0;
  39         var += sizeof("llvm.") - 1;
  40
  41         if (!strcmp(var, "clang-path"))
  42                 llvm_param.clang_path = strdup(value);
  43         else if (!strcmp(var, "clang-bpf-cmd-template"))
  44                 llvm_param.clang_bpf_cmd_template = strdup(value);
  45         else if (!strcmp(var, "clang-opt"))
  46                 llvm_param.clang_opt = strdup(value);
  47         else if (!strcmp(var, "kbuild-dir"))
  48                 llvm_param.kbuild_dir = strdup(value);
  49         else if (!strcmp(var, "kbuild-opts"))
  50                 llvm_param.kbuild_opts = strdup(value);
  51         else if (!strcmp(var, "dump-obj"))
  52                 llvm_param.dump_obj = !!perf_config_bool(var, value);
  53         else {
  54                 pr_debug("Invalid LLVM config option: %s\n", value);
  55                 return -1;
  56         }
  57         llvm_param.user_set_param = true;
  58         return 0;
  59 }
  60
  61 static int
  62 search_program(const char *def, const char *name,
  63                char *output)
  64 {
  65         char *env, *path, *tmp = NULL;
  66         char buf[PATH_MAX];
  67         int ret;
  68
  69         output[0] = '\0';
  70         if (def && def[0] != '\0') {
  71                 if (def[0] == '/') {
  72                         if (access(def, F_OK) == 0) {
  73                                 strlcpy(output, def, PATH_MAX);
  74                                 return 0;
  75                         }
  76                 } else if (def[0] != '\0')
  77                         name = def;
  78         }
  79
  80         env = getenv("PATH");
  81         if (!env)
  82                 return -1;
  83         env = strdup(env);
  84         if (!env)
  85                 return -1;
  86
  87         ret = -ENOENT;
  88         path = strtok_r(env, ":",  &tmp);
  89         while (path) {
  90                 scnprintf(buf, sizeof(buf), "%s/%s", path, name);
  91                 if (access(buf, F_OK) == 0) {
  92                         strlcpy(output, buf, PATH_MAX);
  93                         ret = 0;
  94                         break;
  95                 }
  96                 path = strtok_r(NULL, ":", &tmp);
  97         }
  98
  99         free(env);
 100         return ret;
 101 }
 102
 103 #define READ_SIZE       4096
 104 static int
 105 read_from_pipe(const char *cmd, void **p_buf, size_t *p_read_sz)
 106 {
 107         int err = 0;
 108         void *buf = NULL;
 109         FILE *file = NULL;
 110         size_t read_sz = 0, buf_sz = 0;
 111         char serr[STRERR_BUFSIZE];
 112
 113         file = popen(cmd, "r");
 114         if (!file) {
 115                 pr_err("ERROR: unable to popen cmd: %s\n",
 116                        str_error_r(errno, serr, sizeof(serr)));
 117                 return -EINVAL;
 118         }
 119
 120         while (!feof(file) && !ferror(file)) {
 121                 /*
 122                  * Make buf_sz always have obe byte extra space so we
 123                  * can put '\0' there.
 124                  */
 125                 if (buf_sz - read_sz < READ_SIZE + 1) {
 126                         void *new_buf;
 127
 128                         buf_sz = read_sz + READ_SIZE + 1;
 129                         new_buf = realloc(buf, buf_sz);
 130
 131                         if (!new_buf) {
 132                                 pr_err("ERROR: failed to realloc memory\n");
 133                                 err = -ENOMEM;
 134                                 goto errout;
 135                         }
 136
 137                         buf = new_buf;
 138                 }
 139                 read_sz += fread(buf + read_sz, 1, READ_SIZE, file);
 140         }
 141
 142         if (buf_sz - read_sz < 1) {
 143                 pr_err("ERROR: internal error\n");
 144                 err = -EINVAL;
 145                 goto errout;
 146         }
 147
 148         if (ferror(file)) {
 149                 pr_err("ERROR: error occurred when reading from pipe: %s\n",
 150                        str_error_r(errno, serr, sizeof(serr)));
 151                 err = -EIO;
 152                 goto errout;
 153         }
 154
 155         err = WEXITSTATUS(pclose(file));
 156         file = NULL;
 157         if (err) {
 158                 err = -EINVAL;
 159                 goto errout;
 160         }
 161
 162         /*
 163          * If buf is string, give it terminal '\0' to make our life
 164          * easier. If buf is not string, that '\0' is out of space
 165          * indicated by read_sz so caller won't even notice it.
 166          */
 167         ((char *)buf)[read_sz] = '\0';
 168
 169         if (!p_buf)
 170                 free(buf);
 171         else
 172                 *p_buf = buf;
 173
 174         if (p_read_sz)
 175                 *p_read_sz = read_sz;
 176         return 0;
 177
 178 errout:
 179         if (file)
 180                 pclose(file);
 181         free(buf);
 182         if (p_buf)
 183                 *p_buf = NULL;
 184         if (p_read_sz)
 185                 *p_read_sz = 0;
 186         return err;
 187 }
 188
 189 static inline void
 190 force_set_env(const char *var, const char *value)
 191 {
 192         if (value) {
 193                 setenv(var, value, 1);
 194                 pr_debug("set env: %s=%s\n", var, value);
 195         } else {
 196                 unsetenv(var);
 197                 pr_debug("unset env: %s\n", var);
 198         }
 199 }
 200
 201 static void
 202 version_notice(void)
 203 {
 204         pr_err(
 205 "     \tLLVM 3.7 or newer is required. Which can be found from http://llvm.org\n"
 206 "     \tYou may want to try git trunk:\n"
 207 "     \t\tgit clone http://llvm.org/git/llvm.git\n"
 208 "     \t\t     and\n"
 209 "     \t\tgit clone http://llvm.org/git/clang.git\n\n"
 210 "     \tOr fetch the latest clang/llvm 3.7 from pre-built llvm packages for\n"
 211 "     \tdebian/ubuntu:\n"
 212 "     \t\thttp://llvm.org/apt\n\n"
 213 "     \tIf you are using old version of clang, change 'clang-bpf-cmd-template'\n"
 214 "     \toption in [llvm] section of ~/.perfconfig to:\n\n"
 215 "     \t  \"$CLANG_EXEC $CLANG_OPTIONS $KERNEL_INC_OPTIONS \\\n"
 216 "     \t     -working-directory $WORKING_DIR -c $CLANG_SOURCE \\\n"
 217 "     \t     -emit-llvm -o - | /path/to/llc -march=bpf -filetype=obj -o -\"\n"
 218 "     \t(Replace /path/to/llc with path to your llc)\n\n"
 219 );
 220 }
 221
 222 static int detect_kbuild_dir(char **kbuild_dir)
 223 {
 224         const char *test_dir = llvm_param.kbuild_dir;
 225         const char *prefix_dir = "";
 226         const char *suffix_dir = "";
 227
 228         char *autoconf_path;
 229
 230         int err;
 231
 232         if (!test_dir) {
 233                 /* _UTSNAME_LENGTH is 65 */
 234                 char release[128];
 235
 236                 err = fetch_kernel_version(NULL, release,
 237                                            sizeof(release));
 238                 if (err)
 239                         return -EINVAL;
 240
 241                 test_dir = release;
 242                 prefix_dir = "/lib/modules/";
 243                 suffix_dir = "/build";
 244         }
 245
 246         err = asprintf(&autoconf_path, "%s%s%s/include/generated/autoconf.h",
 247                        prefix_dir, test_dir, suffix_dir);
 248         if (err < 0)
 249                 return -ENOMEM;
 250
 251         if (access(autoconf_path, R_OK) == 0) {
 252                 free(autoconf_path);
 253
 254                 err = asprintf(kbuild_dir, "%s%s%s", prefix_dir, test_dir,
 255                                suffix_dir);
 256                 if (err < 0)
 257                         return -ENOMEM;
 258                 return 0;
 259         }
 260         free(autoconf_path);
 261         return -ENOENT;
 262 }
 263
 264 static const char *kinc_fetch_script =
 265 "#!/usr/bin/env sh\n"
 266 "if ! test -d \"$KBUILD_DIR\"\n"
 267 "then\n"
 268 "       exit -1\n"
 269 "fi\n"
 270 "if ! test -f \"$KBUILD_DIR/include/generated/autoconf.h\"\n"
 271 "then\n"
 272 "       exit -1\n"
 273 "fi\n"
 274 "TMPDIR=`mktemp -d`\n"
 275 "if test -z \"$TMPDIR\"\n"
 276 "then\n"
 277 "    exit -1\n"
 278 "fi\n"
 279 "cat << EOF > $TMPDIR/Makefile\n"
 280 "obj-y := dummy.o\n"
 281 "\\$(obj)/%.o: \\$(src)/%.c\n"
 282 "\t@echo -n \"\\$(NOSTDINC_FLAGS) \\$(LINUXINCLUDE) \\$(EXTRA_CFLAGS)\"\n"
 283 "EOF\n"
 284 "touch $TMPDIR/dummy.c\n"
 285 "make -s -C $KBUILD_DIR M=$TMPDIR $KBUILD_OPTS dummy.o 2>/dev/null\n"
 286 "RET=$?\n"
 287 "rm -rf $TMPDIR\n"
 288 "exit $RET\n";
 289
 290 void llvm__get_kbuild_opts(char **kbuild_dir, char **kbuild_include_opts)
 291 {
 292         static char *saved_kbuild_dir;
 293         static char *saved_kbuild_include_opts;
 294         int err;
 295
 296         if (!kbuild_dir || !kbuild_include_opts)
 297                 return;
 298
 299         *kbuild_dir = NULL;
 300         *kbuild_include_opts = NULL;
 301
 302         if (saved_kbuild_dir && saved_kbuild_include_opts &&
 303             !IS_ERR(saved_kbuild_dir) && !IS_ERR(saved_kbuild_include_opts)) {
 304                 *kbuild_dir = strdup(saved_kbuild_dir);
 305                 *kbuild_include_opts = strdup(saved_kbuild_include_opts);
 306
 307                 if (*kbuild_dir && *kbuild_include_opts)
 308                         return;
 309
 310                 zfree(kbuild_dir);
 311                 zfree(kbuild_include_opts);
 312                 /*
 313                  * Don't fall through: it may breaks saved_kbuild_dir and
 314                  * saved_kbuild_include_opts if detect them again when
 315                  * memory is low.
 316                  */
 317                 return;
 318         }
 319
 320         if (llvm_param.kbuild_dir && !llvm_param.kbuild_dir[0]) {
 321                 pr_debug("[llvm.kbuild-dir] is set to \"\" deliberately.\n");
 322                 pr_debug("Skip kbuild options detection.\n");
 323                 goto errout;
 324         }
 325
 326         err = detect_kbuild_dir(kbuild_dir);
 327         if (err) {
 328                 pr_warning(
 329 "WARNING:\tunable to get correct kernel building directory.\n"
 330 "Hint:\tSet correct kbuild directory using 'kbuild-dir' option in [llvm]\n"
 331 "     \tsection of ~/.perfconfig or set it to \"\" to suppress kbuild\n"
 332 "     \tdetection.\n\n");
 333                 goto errout;
 334         }
 335
 336         pr_debug("Kernel build dir is set to %s\n", *kbuild_dir);
 337         force_set_env("KBUILD_DIR", *kbuild_dir);
 338         force_set_env("KBUILD_OPTS", llvm_param.kbuild_opts);
 339         err = read_from_pipe(kinc_fetch_script,
 340                              (void **)kbuild_include_opts,
 341                              NULL);
 342         if (err) {
 343                 pr_warning(
 344 "WARNING:\tunable to get kernel include directories from '%s'\n"
 345 "Hint:\tTry set clang include options using 'clang-bpf-cmd-template'\n"
 346 "     \toption in [llvm] section of ~/.perfconfig and set 'kbuild-dir'\n"
 347 "     \toption in [llvm] to \"\" to suppress this detection.\n\n",
 348                         *kbuild_dir);
 349
 350                 free(*kbuild_dir);
 351                 *kbuild_dir = NULL;
 352                 goto errout;
 353         }
 354
 355         pr_debug("include option is set to %s\n", *kbuild_include_opts);
 356
 357         saved_kbuild_dir = strdup(*kbuild_dir);
 358         saved_kbuild_include_opts = strdup(*kbuild_include_opts);
 359
 360         if (!saved_kbuild_dir || !saved_kbuild_include_opts) {
 361                 zfree(&saved_kbuild_dir);
 362                 zfree(&saved_kbuild_include_opts);
 363         }
 364         return;
 365 errout:
 366         saved_kbuild_dir = ERR_PTR(-EINVAL);
 367         saved_kbuild_include_opts = ERR_PTR(-EINVAL);
 368 }
 369
 370 int llvm__get_nr_cpus(void)
 371 {
 372         static int nr_cpus_avail = 0;
 373         char serr[STRERR_BUFSIZE];
 374
 375         if (nr_cpus_avail > 0)
 376                 return nr_cpus_avail;
 377
 378         nr_cpus_avail = sysconf(_SC_NPROCESSORS_CONF);
 379         if (nr_cpus_avail <= 0) {
 380                 pr_err(
 381 "WARNING:\tunable to get available CPUs in this system: %s\n"
 382 "        \tUse 128 instead.\n", str_error_r(errno, serr, sizeof(serr)));
 383                 nr_cpus_avail = 128;
 384         }
 385         return nr_cpus_avail;
 386 }
 387
 388 void llvm__dump_obj(const char *path, void *obj_buf, size_t size)
 389 {
 390         char *obj_path = strdup(path);
 391         FILE *fp;
 392         char *p;
 393
 394         if (!obj_path) {
 395                 pr_warning("WARNING: Not enough memory, skip object dumping\n");
 396                 return;
 397         }
 398
 399         p = strrchr(obj_path, '.');
 400         if (!p || (strcmp(p, ".c") != 0)) {
 401                 pr_warning("WARNING: invalid llvm source path: '%s', skip object dumping\n",
 402                            obj_path);
 403                 goto out;
 404         }
 405
 406         p[1] = 'o';
 407         fp = fopen(obj_path, "wb");
 408         if (!fp) {
 409                 pr_warning("WARNING: failed to open '%s': %s, skip object dumping\n",
 410                            obj_path, strerror(errno));
 411                 goto out;
 412         }
 413
 414         pr_info("LLVM: dumping %s\n", obj_path);
 415         if (fwrite(obj_buf, size, 1, fp) != 1)
 416                 pr_warning("WARNING: failed to write to file '%s': %s, skip object dumping\n",
 417                            obj_path, strerror(errno));
 418         fclose(fp);
 419 out:
 420         free(obj_path);
 421 }
 422
 423 int llvm__compile_bpf(const char *path, void **p_obj_buf,
 424                       size_t *p_obj_buf_sz)
 425 {
 426         size_t obj_buf_sz;
 427         void *obj_buf = NULL;
 428         int err, nr_cpus_avail;
 429         unsigned int kernel_version;
 430         char linux_version_code_str[64];
 431         const char *clang_opt = llvm_param.clang_opt;
 432         char clang_path[PATH_MAX], abspath[PATH_MAX], nr_cpus_avail_str[64];
 433         char serr[STRERR_BUFSIZE];
 434         char *kbuild_dir = NULL, *kbuild_include_opts = NULL;
 435         const char *template = llvm_param.clang_bpf_cmd_template;
 436
 437         if (path[0] != '-' && realpath(path, abspath) == NULL) {
 438                 err = errno;
 439                 pr_err("ERROR: problems with path %s: %s\n",
 440                        path, str_error_r(err, serr, sizeof(serr)));
 441                 return -err;
 442         }
 443
 444         if (!template)
 445                 template = CLANG_BPF_CMD_DEFAULT_TEMPLATE;
 446
 447         err = search_program(llvm_param.clang_path,
 448                              "clang", clang_path);
 449         if (err) {
 450                 pr_err(
 451 "ERROR:\tunable to find clang.\n"
 452 "Hint:\tTry to install latest clang/llvm to support BPF. Check your $PATH\n"
 453 "     \tand 'clang-path' option in [llvm] section of ~/.perfconfig.\n");
 454                 version_notice();
 455                 return -ENOENT;
 456         }
 457
 458         /*
 459          * This is an optional work. Even it fail we can continue our
 460          * work. Needn't to check error return.
 461          */
 462         llvm__get_kbuild_opts(&kbuild_dir, &kbuild_include_opts);
 463
 464         nr_cpus_avail = llvm__get_nr_cpus();
 465         snprintf(nr_cpus_avail_str, sizeof(nr_cpus_avail_str), "%d",
 466                  nr_cpus_avail);
 467
 468         if (fetch_kernel_version(&kernel_version, NULL, 0))
 469                 kernel_version = 0;
 470
 471         snprintf(linux_version_code_str, sizeof(linux_version_code_str),
 472                  "0x%x", kernel_version);
 473
 474         force_set_env("NR_CPUS", nr_cpus_avail_str);
 475         force_set_env("LINUX_VERSION_CODE", linux_version_code_str);
 476         force_set_env("CLANG_EXEC", clang_path);
 477         force_set_env("CLANG_OPTIONS", clang_opt);
 478         force_set_env("KERNEL_INC_OPTIONS", kbuild_include_opts);
 479         force_set_env("WORKING_DIR", kbuild_dir ? : ".");
 480
 481         /*
 482          * Since we may reset clang's working dir, path of source file
 483          * should be transferred into absolute path, except we want
 484          * stdin to be source file (testing).
 485          */
 486         force_set_env("CLANG_SOURCE",
 487                       (path[0] == '-') ? path : abspath);
 488
 489         pr_debug("llvm compiling command template: %s\n", template);
 490         err = read_from_pipe(template, &obj_buf, &obj_buf_sz);
 491         if (err) {
 492                 pr_err("ERROR:\tunable to compile %s\n", path);
 493                 pr_err("Hint:\tCheck error message shown above.\n");
 494                 pr_err("Hint:\tYou can also pre-compile it into .o using:\n");
 495                 pr_err("     \t\tclang -target bpf -O2 -c %s\n", path);
 496                 pr_err("     \twith proper -I and -D options.\n");
 497                 goto errout;
 498         }
 499
 500         free(kbuild_dir);
 501         free(kbuild_include_opts);
 502
 503         if (!p_obj_buf)
 504                 free(obj_buf);
 505         else
 506                 *p_obj_buf = obj_buf;
 507
 508         if (p_obj_buf_sz)
 509                 *p_obj_buf_sz = obj_buf_sz;
 510         return 0;
 511 errout:
 512         free(kbuild_dir);
 513         free(kbuild_include_opts);
 514         free(obj_buf);
 515         if (p_obj_buf)
 516                 *p_obj_buf = NULL;
 517         if (p_obj_buf_sz)
 518                 *p_obj_buf_sz = 0;
 519         return err;
 520 }
 521
 522 int llvm__search_clang(void)
 523 {
 524         char clang_path[PATH_MAX];
 525
 526         return search_program(llvm_param.clang_path, "clang", clang_path);
 527 }