mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-16 10:20:30 +00:00
Determine where the runtime loader got mapped to when a dynamically
linked process was exec()'ed, and map samples in that address range into the appropriate buckets in the runtime loader's profile. Improve a few comments. MFC after: 3 days
This commit is contained in:
Joseph Koshy
parent
dedaf3ca1f
commit
60f918ef43
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=150139
@ -78,11 +78,11 @@ __FBSDID("$FreeBSD$");
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#define max(A,B) ((A) > (B) ? (A) : (B))
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/*
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* A simple implementation to intern strings. Each interned string is
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* assigned a unique address, so that subsequent string compares can
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* be done by a simple pointer comparision.
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* A simple implementation of interned strings. Each interned string
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* is assigned a unique address, so that subsequent string compares
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* can be done by a simple pointer comparision instead of with
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* strcmp().
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*/
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struct pmcstat_string {
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LIST_ENTRY(pmcstat_string) ps_next; /* hash link */
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int ps_len;
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@ -143,12 +143,14 @@ struct pmcstat_image {
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LIST_ENTRY(pmcstat_image) pi_next; /* hash link */
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TAILQ_ENTRY(pmcstat_image) pi_lru; /* LRU list */
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const char *pi_internedpath; /* cookie */
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const char *pi_samplename; /* sample file name */
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const char *pi_samplename; /* sample path name */
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enum pmcstat_image_type pi_type; /* executable type */
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uintfptr_t pi_start; /* start address (inclusive) */
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uintfptr_t pi_end; /* end address (exclusive) */
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uintfptr_t pi_entry; /* entry address */
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int pi_isdynamic; /* whether a dynamic object */
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const char *pi_dynlinkerpath; /* path in .interp section */
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LIST_HEAD(,pmcstat_gmonfile) pi_gmlist;
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};
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@ -172,6 +174,7 @@ struct pmcstat_process {
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LIST_ENTRY(pmcstat_process) pp_next; /* hash-next */
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pid_t pp_pid; /* associated pid */
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int pp_isactive; /* whether active */
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uintfptr_t pp_entryaddr; /* entry address */
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TAILQ_HEAD(,pmcstat_pcmap) pp_map; /* address range map */
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};
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@ -192,8 +195,7 @@ static void pmcstat_gmon_unmap_file(struct pmcstat_gmonfile *_pgf);
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static struct pmcstat_image *pmcstat_image_from_path(const char *_path);
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static enum pmcstat_image_type pmcstat_image_get_type(const char *_p);
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static void pmcstat_image_get_elf_params(struct pmcstat_image *_image,
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uintfptr_t *_minp, uintfptr_t *_maxp, int *_isdyn);
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static void pmcstat_image_get_elf_params(struct pmcstat_image *_image);
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static void pmcstat_image_increment_bucket(struct pmcstat_pcmap *_pcm,
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uintfptr_t _pc, pmc_id_t _pmcid, struct pmcstat_args *_a);
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static void pmcstat_image_link(struct pmcstat_process *_pp,
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@ -204,12 +206,12 @@ static void pmcstat_pmcid_add(pmc_id_t _pmcid, const char *_name,
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static const char *pmcstat_pmcid_to_name(pmc_id_t _pmcid);
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static void pmcstat_process_add_elf_image(struct pmcstat_process *_pp,
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const char *_path);
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const char *_path, uintfptr_t _entryaddr);
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static void pmcstat_process_exec(struct pmcstat_process *_pp,
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const char *_path, uintfptr_t _entryaddr);
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static struct pmcstat_process *pmcstat_process_lookup(pid_t _pid, int _allocate);
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static struct pmcstat_pcmap *pmcstat_process_find_map(
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struct pmcstat_process *_p, uintfptr_t _pc);
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static void pmcstat_process_new_image(struct pmcstat_process *_pp,
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const char *_path);
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static int pmcstat_string_compute_hash(const char *_string);
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static const char *pmcstat_string_intern(const char *_s);
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@ -317,8 +319,7 @@ pmcstat_gmon_unmap_file(struct pmcstat_gmonfile *pgf)
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}
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static void
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pmcstat_image_get_elf_params(struct pmcstat_image *image, uintfptr_t *minp,
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uintfptr_t *maxp, int *is_dynamic)
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pmcstat_image_get_elf_params(struct pmcstat_image *image)
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{
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int fd, i;
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struct stat st;
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@ -329,6 +330,8 @@ pmcstat_image_get_elf_params(struct pmcstat_image *image, uintfptr_t *minp,
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const Elf_Shdr *sh;
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const char *path;
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assert(image->pi_type == PMCSTAT_IMAGE_UNKNOWN);
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minva = ~(uintfptr_t) 0;
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maxva = (uintfptr_t) 0;
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path = image->pi_internedpath;
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@ -353,8 +356,8 @@ pmcstat_image_get_elf_params(struct pmcstat_image *image, uintfptr_t *minp,
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if (h->e_type == ET_EXEC || h->e_type == ET_DYN) {
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/*
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* Some kind of shared object: find the min,max va for
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* its executable sections.
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* Some kind of executable object: find the min,max va
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* for its executable sections.
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*/
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for (i = 0; i < h->e_shnum; i++)
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if (sh[i].sh_flags & SHF_EXECINSTR) { /* code */
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@ -366,13 +369,25 @@ pmcstat_image_get_elf_params(struct pmcstat_image *image, uintfptr_t *minp,
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err(EX_DATAERR, "ERROR: Unknown file type for \"%s\"",
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image->pi_internedpath);
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*is_dynamic = 0;
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image->pi_type = PMCSTAT_IMAGE_ELF;
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image->pi_start = minva;
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image->pi_entry = h->e_entry;
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image->pi_end = maxva;
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image->pi_isdynamic = 0;
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image->pi_dynlinkerpath = NULL;
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if (h->e_type == ET_EXEC) {
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ph = (const Elf_Phdr *)((uintptr_t) mapbase + h->e_phoff);
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for (i = 0; i < h->e_phnum; i++) {
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switch (ph[i].p_type) {
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case PT_DYNAMIC:
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*is_dynamic = 1;
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image->pi_isdynamic = 1;
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break;
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case PT_INTERP:
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image->pi_dynlinkerpath =
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pmcstat_string_intern((char *) mapbase +
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ph[i].p_offset);
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break;
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}
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}
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@ -381,13 +396,12 @@ pmcstat_image_get_elf_params(struct pmcstat_image *image, uintfptr_t *minp,
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if (munmap(mapbase, st.st_size) < 0)
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err(EX_OSERR, "ERROR: Cannot unmap \"%s\"", path);
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*minp = minva;
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*maxp = maxva;
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}
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/*
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* Locate an image descriptor given an interned path.
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* Locate an image descriptor given an interned path, adding a fresh
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* descriptor to the cache if necessary. This function also finds a
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* suitable name for this image's sample file.
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*/
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static struct pmcstat_image *
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@ -400,7 +414,7 @@ pmcstat_image_from_path(const char *internedpath)
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hash = pmcstat_string_compute_hash(internedpath);
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/* look for an existing entry */
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/* Look for an existing entry. */
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LIST_FOREACH(pi, &pmcstat_image_hash[hash], pi_next)
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if (pi->pi_internedpath == internedpath) {
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/* move descriptor to the head of the lru list */
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@ -410,8 +424,8 @@ pmcstat_image_from_path(const char *internedpath)
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}
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/*
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* allocate a new entry and place at the head of the hash and
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* LRU lists
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* Allocate a new entry and place at the head of the hash and
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* LRU lists.
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*/
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pi = malloc(sizeof(*pi));
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if (pi == NULL)
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@ -420,17 +434,23 @@ pmcstat_image_from_path(const char *internedpath)
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pi->pi_type = PMCSTAT_IMAGE_UNKNOWN;
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pi->pi_internedpath = internedpath;
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pi->pi_start = ~0;
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pi->pi_entry = ~0;
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pi->pi_end = 0;
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/* look for a suitable name for the sample files */
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/*
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* Look for a suitable name for the sample files associated
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* with this image: if `basename(path)`+".gmon" is available,
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* we use that, otherwise we try iterating through
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* `basename(path)`+ "~" + NNN + ".gmon" till we get a free
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* entry.
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*/
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if ((sn = basename(internedpath)) == NULL)
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err(EX_OSERR, "ERROR: Cannot process \"%s\"", internedpath);
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nlen = strlen(sn);
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nlen = min(nlen, (int) sizeof(name) - 6); /* ".gmon\0" */
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snprintf(name, sizeof(name), "%.*s.gmon",
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nlen, sn);
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snprintf(name, sizeof(name), "%.*s.gmon", nlen, sn);
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if (pmcstat_string_lookup(name) == NULL)
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pi->pi_samplename = pmcstat_string_intern(name);
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@ -532,6 +552,7 @@ pmcstat_image_increment_bucket(struct pmcstat_pcmap *map, uintfptr_t pc,
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pgf->pgf_name = pmcstat_gmon_create_name(a->pa_samplesdir,
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image, pmcid);
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pgf->pgf_pmcid = pmcid;
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assert(image->pi_end > image->pi_start);
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pgf->pgf_nbuckets = (image->pi_end - image->pi_start) /
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FUNCTION_ALIGNMENT; /* see <machine/profile.h> */
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pgf->pgf_ndatabytes = sizeof(struct gmonhdr) +
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@ -659,41 +680,65 @@ pmcstat_pmcid_to_name(pmc_id_t pmcid)
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*/
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static void
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pmcstat_process_add_elf_image(struct pmcstat_process *pp, const char *path)
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pmcstat_process_add_elf_image(struct pmcstat_process *pp, const char *path,
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uintfptr_t entryaddr)
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{
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int isdynamic;
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size_t linelen;
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FILE *rf;
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char *line;
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uintfptr_t minva, maxva;
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uintmax_t libstart;
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struct pmcstat_image *image;
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struct pmcstat_image *image, *rtldimage;
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char libpath[PATH_MAX];
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char command[PATH_MAX + sizeof(PMCSTAT_LDD_COMMAND) + 1];
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minva = ~ (uintfptr_t) 0;
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maxva = (uintfptr_t) 0;
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isdynamic = 0;
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/* Look up path in the cache. */
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if ((image = pmcstat_image_from_path(path)) == NULL)
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return;
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if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN) {
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if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN)
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pmcstat_image_get_elf_params(image);
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pmcstat_image_get_elf_params(image, &minva, &maxva,
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&isdynamic);
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image->pi_type = PMCSTAT_IMAGE_ELF;
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image->pi_start = minva;
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image->pi_end = maxva;
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image->pi_isdynamic = isdynamic;
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}
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/* create a map entry for the base executable */
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pmcstat_image_link(pp, image, minva, maxva);
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/* Create a map entry for the base executable. */
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pmcstat_image_link(pp, image, image->pi_start, image->pi_end);
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/*
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* For dynamically linked executables we need to:
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* (a) find where the dynamic linker was mapped to for this
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* process,
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* (b) find all the executable objects that the dynamic linker
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* brought in.
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*/
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if (image->pi_isdynamic) {
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/*
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* The runtime loader gets loaded just after the maximum
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* possible heap address. Like so:
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*
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* [ TEXT DATA BSS HEAP -->*RTLD SHLIBS <--STACK]
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* ^ ^
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* 0 VM_MAXUSER_ADDRESS
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*
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* The exact address where the loader gets mapped in
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* will vary according to the size of the executable
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* and the limits on the size of the process'es data
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* segment at the time of exec(). The entry address
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* recorded at process exec time corresponds to the
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* 'start' address inside the dynamic linker. From
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* this we can figure out the address where the
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* runtime loader's file object had been mapped to.
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*/
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rtldimage = pmcstat_image_from_path(image->pi_dynlinkerpath);
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if (rtldimage == NULL)
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err(EX_OSERR, "ERROR: Cannot find image for "
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"\"%s\"", image->pi_dynlinkerpath);
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if (rtldimage->pi_type == PMCSTAT_IMAGE_UNKNOWN)
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pmcstat_image_get_elf_params(rtldimage);
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libstart = entryaddr - rtldimage->pi_entry;
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pmcstat_image_link(pp, rtldimage, libstart,
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libstart + rtldimage->pi_end - rtldimage->pi_start);
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/* Process all other objects loaded by this executable. */
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(void) snprintf(command, sizeof(command), "%s %s",
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PMCSTAT_LDD_COMMAND, path);
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@ -718,16 +763,8 @@ pmcstat_process_add_elf_image(struct pmcstat_process *pp, const char *path)
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err(EX_OSERR, "ERROR: Cannot process "
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"\"%s\"", libpath);
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if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN) {
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pmcstat_image_get_elf_params(image,
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&minva, &maxva, &isdynamic);
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image->pi_type = PMCSTAT_IMAGE_ELF;
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image->pi_start = minva;
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image->pi_end = maxva;
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image->pi_isdynamic = isdynamic;
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}
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if (image->pi_type == PMCSTAT_IMAGE_UNKNOWN)
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pmcstat_image_get_elf_params(image);
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pmcstat_image_link(pp, image, libstart + image->pi_start,
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libstart + image->pi_end);
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@ -789,28 +826,13 @@ pmcstat_process_lookup(pid_t pid, int allocate)
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return pp;
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}
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/*
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* Find the map entry associated with process 'p' at PC value 'pc'.
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*/
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static struct pmcstat_pcmap *
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pmcstat_process_find_map(struct pmcstat_process *p, uintfptr_t pc)
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{
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struct pmcstat_pcmap *ppm;
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TAILQ_FOREACH(ppm, &p->pp_map, ppm_next)
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if (pc >= ppm->ppm_lowpc && pc < ppm->ppm_highpc)
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return ppm;
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return NULL;
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}
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/*
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* Associate an image and a process.
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*/
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static void
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pmcstat_process_new_image(struct pmcstat_process *pp, const char *path)
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pmcstat_process_exec(struct pmcstat_process *pp, const char *path,
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uintfptr_t entryaddr)
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{
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enum pmcstat_image_type filetype;
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struct pmcstat_image *image;
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@ -825,19 +847,35 @@ pmcstat_process_new_image(struct pmcstat_process *pp, const char *path)
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switch (filetype) {
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case PMCSTAT_IMAGE_ELF:
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pmcstat_process_add_elf_image(pp, path);
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pmcstat_process_add_elf_image(pp, path, entryaddr);
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break;
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case PMCSTAT_IMAGE_AOUT:
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break;
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default:
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err(EX_SOFTWARE, "ERROR: Unsupported executable type \"%s\"",
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path);
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err(EX_SOFTWARE, "ERROR: Unsupported executable type for "
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"\"%s\"", path);
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}
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}
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/*
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* Find the map entry associated with process 'p' at PC value 'pc'.
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*/
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static struct pmcstat_pcmap *
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pmcstat_process_find_map(struct pmcstat_process *p, uintfptr_t pc)
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{
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struct pmcstat_pcmap *ppm;
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TAILQ_FOREACH(ppm, &p->pp_map, ppm_next)
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if (pc >= ppm->ppm_lowpc && pc < ppm->ppm_highpc)
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return ppm;
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return NULL;
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}
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/*
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* Compute a 'hash' value for a string.
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@ -983,7 +1021,8 @@ pmcstat_convert_log(struct pmcstat_args *a)
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ev.pl_u.pl_x.pl_pathname);
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/* link to the new image */
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pmcstat_process_new_image(pp, image_path);
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pmcstat_process_exec(pp, image_path,
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ev.pl_u.pl_x.pl_entryaddr);
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break;
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case PMCLOG_TYPE_PROCEXIT:
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@ -1198,10 +1237,9 @@ pmcstat_process_log(struct pmcstat_args *a)
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void
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pmcstat_initialize_logging(struct pmcstat_args *a)
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{
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int i, isdynamic;
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int i;
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const char *kernpath;
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struct pmcstat_image *img;
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uintfptr_t minva, maxva;
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/* use a convenient format for 'ldd' output */
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if (setenv("LD_TRACE_LOADED_OBJECTS_FMT1","%p %x\n",1) != 0)
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@ -1223,12 +1261,8 @@ pmcstat_initialize_logging(struct pmcstat_args *a)
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img = pmcstat_image_from_path(kernpath);
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pmcstat_image_get_elf_params(img, &minva, &maxva, &isdynamic);
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img->pi_type = PMCSTAT_IMAGE_ELF;
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img->pi_start = minva;
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img->pi_end = maxva;
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pmcstat_image_link(pmcstat_kernproc, img, minva, maxva);
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pmcstat_image_get_elf_params(img);
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pmcstat_image_link(pmcstat_kernproc, img, img->pi_start, img->pi_end);
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return;
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