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