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