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