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-rw-r--r--elf/dl-profile.c167
1 files changed, 133 insertions, 34 deletions
diff --git a/elf/dl-profile.c b/elf/dl-profile.c
index c8028a7..9b020e8 100644
--- a/elf/dl-profile.c
+++ b/elf/dl-profile.c
@@ -2,6 +2,7 @@
Copyright (C) 1997 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
+ Based on the BSD mcount implementation.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
@@ -30,6 +31,7 @@
#include <sys/gmon_out.h>
#include <sys/mman.h>
#include <sys/stat.h>
+#include <atomicity.h>
/* The LD_PROFILE feature has to be implemented different to the
normal profiling using the gmon/ functions. The problem is that an
@@ -146,19 +148,19 @@ static long int state;
static volatile uint16_t *kcount;
static size_t kcountsize;
-struct here_tostruct
+struct here_fromstruct
{
struct here_cg_arc_record volatile *here;
uint16_t link;
};
-static uint16_t *froms;
-static size_t fromssize;
-
-static struct here_tostruct *tos;
+static uint16_t *tos;
static size_t tossize;
-static size_t tolimit;
-static size_t toidx;
+
+static struct here_fromstruct *froms;
+static size_t fromssize;
+static size_t fromlimit;
+static size_t fromidx;
static uintptr_t lowpc;
static uintptr_t highpc;
@@ -170,6 +172,11 @@ static unsigned int log_hashfraction;
static struct gmon_hdr *addr;
static off_t expected_size;
+/* See profil(2) where this is described. */
+static int s_scale;
+#define SCALE_1_TO_1 0x10000L
+
+
/* Set up profiling data to profile object desribed by MAP. The output
file is found (or created) in OUTPUT_DIR. */
@@ -184,7 +191,7 @@ _dl_start_profile (struct link_map *map, const char *output_dir)
ElfW(Addr) mapend = 0;
struct gmon_hdr gmon_hdr;
struct gmon_hist_hdr hist_hdr;
- char *hist;
+ char *hist, *cp;
size_t idx;
/* Compute the size of the sections which contain program code. */
@@ -205,9 +212,9 @@ _dl_start_profile (struct link_map *map, const char *output_dir)
with the same formulars as in `monstartup' (see gmon.c). */
state = GMON_PROF_OFF;
lowpc = ROUNDDOWN (mapstart + map->l_addr,
- HISTFRACTION * sizeof(HISTCOUNTER));
+ HISTFRACTION * sizeof (HISTCOUNTER));
highpc = ROUNDUP (mapend + map->l_addr,
- HISTFRACTION * sizeof(HISTCOUNTER));
+ HISTFRACTION * sizeof (HISTCOUNTER));
textsize = highpc - lowpc;
kcountsize = textsize / HISTFRACTION;
hashfraction = HASHFRACTION;
@@ -217,17 +224,17 @@ _dl_start_profile (struct link_map *map, const char *output_dir)
log_hashfraction = __builtin_ffs (hashfraction * sizeof (*froms)) - 1;
else
log_hashfraction = -1;
- fromssize = textsize / HASHFRACTION;
- tolimit = textsize * ARCDENSITY / 100;
- if (tolimit < MINARCS)
- tolimit = MINARCS;
- if (tolimit > MAXARCS)
- tolimit = MAXARCS;
- tossize = tolimit * sizeof (struct here_tostruct);
+ tossize = textsize / HASHFRACTION;
+ fromlimit = textsize * ARCDENSITY / 100;
+ if (fromlimit < MINARCS)
+ fromlimit = MINARCS;
+ if (fromlimit > MAXARCS)
+ fromlimit = MAXARCS;
+ fromssize = fromlimit * sizeof (struct here_fromstruct);
expected_size = (sizeof (struct gmon_hdr)
+ 4 + sizeof (struct gmon_hist_hdr) + kcountsize
- + 4 + 4 + tossize * sizeof (struct here_cg_arc_record));
+ + 4 + 4 + fromssize * sizeof (struct here_cg_arc_record));
/* Create the gmon_hdr we expect or write. */
memset (&gmon_hdr, '\0', sizeof (struct gmon_hdr));
@@ -247,9 +254,9 @@ _dl_start_profile (struct link_map *map, const char *output_dir)
soname (or the file name) and the ending ".profile". */
filename = (char *) alloca (strlen (output_dir) + 1 + strlen (_dl_profile)
+ sizeof ".profile");
- __stpcpy (__stpcpy (__stpcpy (__stpcpy (filename, output_dir), "/"),
- _dl_profile),
- ".profile");
+ cp = __stpcpy (filename, output_dir);
+ *cp++ = '/';
+ __stpcpy (__stpcpy (cp, _dl_profile), ".profile");
fd = __open (filename, O_RDWR | O_CREAT, 0666);
if (fd == -1)
@@ -356,7 +363,7 @@ _dl_start_profile (struct link_map *map, const char *output_dir)
}
/* Allocate memory for the froms data and the pointer to the tos records. */
- froms = (uint16_t *) calloc (fromssize + tossize, 1);
+ tos = (uint16_t *) calloc (tossize + fromssize, 1);
if (froms == NULL)
{
__munmap ((void *) addr, expected_size);
@@ -364,8 +371,8 @@ _dl_start_profile (struct link_map *map, const char *output_dir)
/* NOTREACHED */
}
- tos = (struct here_tostruct *) ((char *) froms + fromssize);
- toidx = 0;
+ froms = (struct here_fromstruct *) ((char *) tos + tossize);
+ fromidx = 0;
/* Now we have to process all the arc count entries. BTW: it is
not critical whether the *NARCSP value changes meanwhile. Before
@@ -376,17 +383,26 @@ _dl_start_profile (struct link_map *map, const char *output_dir)
frequently used entries at the front of the list. */
for (idx = narcs = *narcsp; idx > 0; )
{
- size_t from_index;
- size_t newtoidx;
+ size_t to_index;
+ size_t newfromidx;
--idx;
- from_index = ((data[idx].from_pc - lowpc)
- / (hashfraction * sizeof (*froms)));
- newtoidx = toidx++;
- tos[newtoidx].here = &data[idx];
- tos[newtoidx].link = froms[from_index];
- froms[from_index] = newtoidx;
+ to_index = ((data[idx].self_pc - lowpc)
+ / (hashfraction * sizeof (*tos)));
+ newfromidx = fromidx++;
+ froms[newfromidx].here = &data[idx];
+ froms[newfromidx].link = tos[to_index];
+ tos[to_index] = newfromidx;
}
+ /* Setup counting data. */
+ if (kcountsize < highpc - lowpc)
+ s_scale = ((double) kcountsize / (highpc - lowpc)) * SCALE_1_TO_1;
+ else
+ s_scale = SCALE_1_TO_1;
+
+ /* Start the profiler. */
+ __profil ((void *) kcount, kcountsize, lowpc, s_scale);
+
/* Turn on profiling. */
state = GMON_PROF_ON;
}
@@ -395,9 +411,12 @@ _dl_start_profile (struct link_map *map, const char *output_dir)
void
_dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc)
{
- if (state != GMON_PROF_ON)
+ uint16_t *topcindex;
+ size_t i, fromindex;
+ struct here_fromstruct *fromp;
+
+ if (! compare_and_swap (&state, GMON_PROF_ON, GMON_PROF_BUSY))
return;
- state = GMON_PROF_BUSY;
/* Compute relative addresses. The shared object can be loaded at
any address. The value of frompc could be anything. We cannot
@@ -411,6 +430,86 @@ _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc)
if (selfpc >= textsize)
goto done;
+ /* Getting here we now have to find out whether the location was
+ already used. If yes we are lucky and only have to increment a
+ counter (this also has to be atomic). If the entry is new things
+ are getting complicated... */
+
+ /* Avoid integer divide if possible. */
+ if ((HASHFRACTION & (HASHFRACTION - 1)) == 0)
+ i = selfpc >> log_hashfraction;
+ else
+ i = selfpc / (hashfraction * sizeof (*tos));
+
+ topcindex = &tos[i];
+ fromindex = *topcindex;
+
+ if (fromindex == 0)
+ goto check_new_or_add;
+
+ fromp = &froms[fromindex];
+
+ /* We have to look through the chain of arcs whether there is already
+ an entry for our arc. */
+ while (fromp->here->from_pc == frompc)
+ {
+ if (fromp->link != 0)
+ do
+ fromp = &froms[fromp->link];
+ while (fromp->link != 0 && fromp->here->from_pc != frompc);
+
+ if (fromp->link == 0)
+ {
+ topcindex = &fromp->link;
+
+ check_new_or_add:
+ /* Our entry is not among the entries we read so far from the
+ data file. Now see whether we have to update the list. */
+ while (narcs != *narcsp)
+ {
+ size_t to_index;
+ size_t newfromidx;
+ to_index = ((data[narcs].self_pc - lowpc)
+ / (hashfraction * sizeof (*tos)));
+ newfromidx = fromidx++;
+ froms[newfromidx].here = &data[narcs];
+ froms[newfromidx].link = tos[to_index];
+ tos[to_index] = newfromidx;
+ ++narcs;
+ }
+
+ /* If we still have no entry stop searching and insert. */
+ if (*topcindex == 0)
+ {
+ fromidx = 1 + exchange_and_add (narcsp, 1);
+ ++narcs;
+
+ /* In rare cases it could happen that all entries in FROMS are
+ occupied. So we cannot count this anymore. */
+ if (fromidx >= fromlimit)
+ goto done;
+
+ *topcindex = fromindex;
+ fromp = &froms[fromindex];
+
+ fromp = &froms[fromp->link];
+
+ fromp->link = 0;
+ fromp->here->from_pc = frompc;
+ fromp->here->count = 0;
+
+ break;
+ }
+
+ fromp = &froms[*topcindex];
+ }
+ else
+ /* Found in. */
+ break;
+ }
+
+ /* Increment the counter. */
+ atomic_add (&fromp->here->count, 1);
done:
state = GMON_PROF_ON;