afe0c5ee91
2014-10-06 Rong Xu <xur@google.com>
* gcc/Makefile.in: Fix dependence.
* gcc/gcov-counter.def (GCOV_COUNTER_ICALL_TOPNV): Add
indirect call topn profiler.
* gcc/gcov-io.h: Ditto.
* libgcc/Makefile.in: Ditto.
* libgcc/libgcov-driver.c (gcov_sort_n_vals): New utility function.
(gcov_sort_icall_topn_counter): Ditto.
(gcov_sort_topn_counter_arrays): Ditto.
(dump_one_gcov): Sort indirect_call topn counters.
* libgcc/libgcov-merge.c (__gcov_merge_icall_topn): New merge
function.
* libgcc/libgcov-profiler.c (__gcov_topn_value_profiler_body): New
utility function.
(__gcov_indirect_call_topn_profiler): New profiler function.
* libgcc/libgcov-util.c (__gcov_icall_topn_counter_op): New.
* libgcc/libgcov.h: New decls.
From-SVN: r215962
337 lines
10 KiB
C
337 lines
10 KiB
C
/* Routines required for instrumenting a program. */
|
|
/* Compile this one with gcc. */
|
|
/* Copyright (C) 1989-2014 Free Software Foundation, Inc.
|
|
|
|
This file is part of GCC.
|
|
|
|
GCC is free software; you can redistribute it and/or modify it under
|
|
the terms of the GNU General Public License as published by the Free
|
|
Software Foundation; either version 3, or (at your option) any later
|
|
version.
|
|
|
|
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
|
|
WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
for more details.
|
|
|
|
Under Section 7 of GPL version 3, you are granted additional
|
|
permissions described in the GCC Runtime Library Exception, version
|
|
3.1, as published by the Free Software Foundation.
|
|
|
|
You should have received a copy of the GNU General Public License and
|
|
a copy of the GCC Runtime Library Exception along with this program;
|
|
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include "libgcov.h"
|
|
#if !defined(inhibit_libc)
|
|
|
|
#ifdef L_gcov_interval_profiler
|
|
/* If VALUE is in interval <START, START + STEPS - 1>, then increases the
|
|
corresponding counter in COUNTERS. If the VALUE is above or below
|
|
the interval, COUNTERS[STEPS] or COUNTERS[STEPS + 1] is increased
|
|
instead. */
|
|
|
|
void
|
|
__gcov_interval_profiler (gcov_type *counters, gcov_type value,
|
|
int start, unsigned steps)
|
|
{
|
|
gcov_type delta = value - start;
|
|
if (delta < 0)
|
|
counters[steps + 1]++;
|
|
else if (delta >= steps)
|
|
counters[steps]++;
|
|
else
|
|
counters[delta]++;
|
|
}
|
|
#endif
|
|
|
|
#ifdef L_gcov_pow2_profiler
|
|
/* If VALUE is a power of two, COUNTERS[1] is incremented. Otherwise
|
|
COUNTERS[0] is incremented. */
|
|
|
|
void
|
|
__gcov_pow2_profiler (gcov_type *counters, gcov_type value)
|
|
{
|
|
if (value & (value - 1))
|
|
counters[0]++;
|
|
else
|
|
counters[1]++;
|
|
}
|
|
#endif
|
|
|
|
/* Tries to determine the most common value among its inputs. Checks if the
|
|
value stored in COUNTERS[0] matches VALUE. If this is the case, COUNTERS[1]
|
|
is incremented. If this is not the case and COUNTERS[1] is not zero,
|
|
COUNTERS[1] is decremented. Otherwise COUNTERS[1] is set to one and
|
|
VALUE is stored to COUNTERS[0]. This algorithm guarantees that if this
|
|
function is called more than 50% of the time with one value, this value
|
|
will be in COUNTERS[0] in the end.
|
|
|
|
In any case, COUNTERS[2] is incremented. */
|
|
|
|
static inline void
|
|
__gcov_one_value_profiler_body (gcov_type *counters, gcov_type value)
|
|
{
|
|
if (value == counters[0])
|
|
counters[1]++;
|
|
else if (counters[1] == 0)
|
|
{
|
|
counters[1] = 1;
|
|
counters[0] = value;
|
|
}
|
|
else
|
|
counters[1]--;
|
|
counters[2]++;
|
|
}
|
|
|
|
#ifdef L_gcov_one_value_profiler
|
|
void
|
|
__gcov_one_value_profiler (gcov_type *counters, gcov_type value)
|
|
{
|
|
__gcov_one_value_profiler_body (counters, value);
|
|
}
|
|
#endif
|
|
|
|
#ifdef L_gcov_indirect_call_topn_profiler
|
|
/* Tries to keep track the most frequent N values in the counters where
|
|
N is specified by parameter TOPN_VAL. To track top N values, 2*N counter
|
|
entries are used.
|
|
counter[0] --- the accumative count of the number of times one entry in
|
|
in the counters gets evicted/replaced due to limited capacity.
|
|
When this value reaches a threshold, the bottom N values are
|
|
cleared.
|
|
counter[1] through counter[2*N] records the top 2*N values collected so far.
|
|
Each value is represented by two entries: count[2*i+1] is the ith value, and
|
|
count[2*i+2] is the number of times the value is seen. */
|
|
|
|
static void
|
|
__gcov_topn_value_profiler_body (gcov_type *counters, gcov_type value)
|
|
{
|
|
unsigned i, found = 0, have_zero_count = 0;
|
|
gcov_type *entry;
|
|
gcov_type *lfu_entry = &counters[1];
|
|
gcov_type *value_array = &counters[1];
|
|
gcov_type *num_eviction = &counters[0];
|
|
gcov_unsigned_t topn_val = GCOV_ICALL_TOPN_VAL;
|
|
|
|
/* There are 2*topn_val values tracked, each value takes two slots in the
|
|
counter array. */
|
|
for (i = 0; i < (topn_val << 2); i += 2)
|
|
{
|
|
entry = &value_array[i];
|
|
if (entry[0] == value)
|
|
{
|
|
entry[1]++ ;
|
|
found = 1;
|
|
break;
|
|
}
|
|
else if (entry[1] == 0)
|
|
{
|
|
lfu_entry = entry;
|
|
have_zero_count = 1;
|
|
}
|
|
else if (entry[1] < lfu_entry[1])
|
|
lfu_entry = entry;
|
|
}
|
|
|
|
if (found)
|
|
return;
|
|
|
|
/* lfu_entry is either an empty entry or an entry
|
|
with lowest count, which will be evicted. */
|
|
lfu_entry[0] = value;
|
|
lfu_entry[1] = 1;
|
|
|
|
#define GCOV_ICALL_COUNTER_CLEAR_THRESHOLD 3000
|
|
|
|
/* Too many evictions -- time to clear bottom entries to
|
|
avoid hot values bumping each other out. */
|
|
if (!have_zero_count
|
|
&& ++*num_eviction >= GCOV_ICALL_COUNTER_CLEAR_THRESHOLD)
|
|
{
|
|
unsigned i, j;
|
|
gcov_type *p, minv;
|
|
gcov_type* tmp_cnts
|
|
= (gcov_type *)alloca (topn_val * sizeof (gcov_type));
|
|
|
|
*num_eviction = 0;
|
|
|
|
for (i = 0; i < topn_val; i++)
|
|
tmp_cnts[i] = 0;
|
|
|
|
/* Find the largest topn_val values from the group of
|
|
2*topn_val values and put them into tmp_cnts. */
|
|
|
|
for (i = 0; i < 2 * topn_val; i += 2)
|
|
{
|
|
p = 0;
|
|
for (j = 0; j < topn_val; j++)
|
|
{
|
|
if (!p || tmp_cnts[j] < *p)
|
|
p = &tmp_cnts[j];
|
|
}
|
|
if (value_array[i + 1] > *p)
|
|
*p = value_array[i + 1];
|
|
}
|
|
|
|
minv = tmp_cnts[0];
|
|
for (j = 1; j < topn_val; j++)
|
|
{
|
|
if (tmp_cnts[j] < minv)
|
|
minv = tmp_cnts[j];
|
|
}
|
|
/* Zero out low value entries. */
|
|
for (i = 0; i < 2 * topn_val; i += 2)
|
|
{
|
|
if (value_array[i + 1] < minv)
|
|
{
|
|
value_array[i] = 0;
|
|
value_array[i + 1] = 0;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* These two variables are used to actually track caller and callee. Keep
|
|
them in TLS memory so races are not common (they are written to often).
|
|
The variables are set directly by GCC instrumented code, so declaration
|
|
here must match one in tree-profile.c. */
|
|
|
|
#if defined(HAVE_CC_TLS) && !defined (USE_EMUTLS)
|
|
__thread
|
|
#endif
|
|
gcov_type *__gcov_indirect_call_topn_counters ATTRIBUTE_HIDDEN;
|
|
|
|
#if defined(HAVE_CC_TLS) && !defined (USE_EMUTLS)
|
|
__thread
|
|
#endif
|
|
void *__gcov_indirect_call_topn_callee ATTRIBUTE_HIDDEN;
|
|
|
|
#ifdef TARGET_VTABLE_USES_DESCRIPTORS
|
|
#define VTABLE_USES_DESCRIPTORS 1
|
|
#else
|
|
#define VTABLE_USES_DESCRIPTORS 0
|
|
#endif
|
|
|
|
/* This fucntion is instrumented at function entry to track topn indirect
|
|
calls to CUR_FUNC. */
|
|
|
|
void
|
|
__gcov_indirect_call_topn_profiler (gcov_type value, void* cur_func)
|
|
{
|
|
void *callee_func = __gcov_indirect_call_topn_callee;
|
|
/* If the C++ virtual tables contain function descriptors then one
|
|
function may have multiple descriptors and we need to dereference
|
|
the descriptors to see if they point to the same function. */
|
|
if (cur_func == callee_func
|
|
|| (VTABLE_USES_DESCRIPTORS && callee_func
|
|
&& *(void **) cur_func == *(void **) callee_func))
|
|
__gcov_topn_value_profiler_body (__gcov_indirect_call_topn_counters, value);
|
|
}
|
|
#endif
|
|
|
|
#ifdef L_gcov_indirect_call_profiler
|
|
/* This function exist only for workaround of binutils bug 14342.
|
|
Once this compatibility hack is obsolette, it can be removed. */
|
|
|
|
/* By default, the C++ compiler will use function addresses in the
|
|
vtable entries. Setting TARGET_VTABLE_USES_DESCRIPTORS to nonzero
|
|
tells the compiler to use function descriptors instead. The value
|
|
of this macro says how many words wide the descriptor is (normally 2).
|
|
|
|
It is assumed that the address of a function descriptor may be treated
|
|
as a pointer to a function. */
|
|
|
|
/* Tries to determine the most common value among its inputs. */
|
|
void
|
|
__gcov_indirect_call_profiler (gcov_type* counter, gcov_type value,
|
|
void* cur_func, void* callee_func)
|
|
{
|
|
/* If the C++ virtual tables contain function descriptors then one
|
|
function may have multiple descriptors and we need to dereference
|
|
the descriptors to see if they point to the same function. */
|
|
if (cur_func == callee_func
|
|
|| (__LIBGCC_VTABLE_USES_DESCRIPTORS__ && callee_func
|
|
&& *(void **) cur_func == *(void **) callee_func))
|
|
__gcov_one_value_profiler_body (counter, value);
|
|
}
|
|
#endif
|
|
|
|
#ifdef L_gcov_indirect_call_profiler_v2
|
|
|
|
/* These two variables are used to actually track caller and callee. Keep
|
|
them in TLS memory so races are not common (they are written to often).
|
|
The variables are set directly by GCC instrumented code, so declaration
|
|
here must match one in tree-profile.c */
|
|
|
|
#if defined(HAVE_CC_TLS) && !defined (USE_EMUTLS)
|
|
__thread
|
|
#endif
|
|
void * __gcov_indirect_call_callee;
|
|
#if defined(HAVE_CC_TLS) && !defined (USE_EMUTLS)
|
|
__thread
|
|
#endif
|
|
gcov_type * __gcov_indirect_call_counters;
|
|
|
|
/* By default, the C++ compiler will use function addresses in the
|
|
vtable entries. Setting TARGET_VTABLE_USES_DESCRIPTORS to nonzero
|
|
tells the compiler to use function descriptors instead. The value
|
|
of this macro says how many words wide the descriptor is (normally 2).
|
|
|
|
It is assumed that the address of a function descriptor may be treated
|
|
as a pointer to a function. */
|
|
|
|
/* Tries to determine the most common value among its inputs. */
|
|
void
|
|
__gcov_indirect_call_profiler_v2 (gcov_type value, void* cur_func)
|
|
{
|
|
/* If the C++ virtual tables contain function descriptors then one
|
|
function may have multiple descriptors and we need to dereference
|
|
the descriptors to see if they point to the same function. */
|
|
if (cur_func == __gcov_indirect_call_callee
|
|
|| (__LIBGCC_VTABLE_USES_DESCRIPTORS__ && __gcov_indirect_call_callee
|
|
&& *(void **) cur_func == *(void **) __gcov_indirect_call_callee))
|
|
__gcov_one_value_profiler_body (__gcov_indirect_call_counters, value);
|
|
}
|
|
#endif
|
|
|
|
#ifdef L_gcov_time_profiler
|
|
|
|
/* Counter for first visit of each function. */
|
|
static gcov_type function_counter;
|
|
|
|
/* Sets corresponding COUNTERS if there is no value. */
|
|
|
|
void
|
|
__gcov_time_profiler (gcov_type* counters)
|
|
{
|
|
if (!counters[0])
|
|
counters[0] = ++function_counter;
|
|
}
|
|
#endif
|
|
|
|
#ifdef L_gcov_average_profiler
|
|
/* Increase corresponding COUNTER by VALUE. FIXME: Perhaps we want
|
|
to saturate up. */
|
|
|
|
void
|
|
__gcov_average_profiler (gcov_type *counters, gcov_type value)
|
|
{
|
|
counters[0] += value;
|
|
counters[1] ++;
|
|
}
|
|
#endif
|
|
|
|
#ifdef L_gcov_ior_profiler
|
|
/* Bitwise-OR VALUE into COUNTER. */
|
|
|
|
void
|
|
__gcov_ior_profiler (gcov_type *counters, gcov_type value)
|
|
{
|
|
*counters |= value;
|
|
}
|
|
#endif
|
|
|
|
#endif /* inhibit_libc */
|