Makefile.in: Fix dependence.
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
diff --git a/libgcc/libgcov-profiler.c b/libgcc/libgcov-profiler.c
index 5f0b052..98f1ae9 100644
--- a/libgcc/libgcov-profiler.c
+++ b/libgcc/libgcov-profiler.c
@@ -93,6 +93,144 @@
}
#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. */
@@ -118,8 +256,8 @@
&& *(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