diff options
Diffstat (limited to 'gcc/gcov-io.c')
| -rw-r--r-- | gcc/gcov-io.c | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/gcc/gcov-io.c b/gcc/gcov-io.c index 116cc03..441aad9 100644 --- a/gcc/gcov-io.c +++ b/gcc/gcov-io.c @@ -837,3 +837,110 @@ static void gcov_histogram_merge (gcov_bucket_type *tgt_histo, memcpy(tgt_histo, tmp_histo, sizeof (gcov_bucket_type) * GCOV_HISTOGRAM_SIZE); } #endif /* !IN_GCOV */ + +/* This is used by gcov-dump (IN_GCOV == -1) and in the compiler + (!IN_GCOV && !IN_LIBGCOV). */ +#if IN_GCOV <= 0 && !IN_LIBGCOV +/* Compute the working set information from the counter histogram in + the profile summary. This is an array of information corresponding to a + range of percentages of the total execution count (sum_all), and includes + the number of counters required to cover that working set percentage and + the minimum counter value in that working set. */ + +GCOV_LINKAGE void +compute_working_sets (const struct gcov_ctr_summary *summary, + gcov_working_set_t *gcov_working_sets) +{ + gcov_type working_set_cum_values[NUM_GCOV_WORKING_SETS]; + gcov_type ws_cum_hotness_incr; + gcov_type cum, tmp_cum; + const gcov_bucket_type *histo_bucket; + unsigned ws_ix, c_num, count; + int h_ix; + + /* Compute the amount of sum_all that the cumulative hotness grows + by in each successive working set entry, which depends on the + number of working set entries. */ + ws_cum_hotness_incr = summary->sum_all / NUM_GCOV_WORKING_SETS; + + /* Next fill in an array of the cumulative hotness values corresponding + to each working set summary entry we are going to compute below. + Skip 0% statistics, which can be extrapolated from the + rest of the summary data. */ + cum = ws_cum_hotness_incr; + for (ws_ix = 0; ws_ix < NUM_GCOV_WORKING_SETS; + ws_ix++, cum += ws_cum_hotness_incr) + working_set_cum_values[ws_ix] = cum; + /* The last summary entry is reserved for (roughly) 99.9% of the + working set. Divide by 1024 so it becomes a shift, which gives + almost exactly 99.9%. */ + working_set_cum_values[NUM_GCOV_WORKING_SETS-1] + = summary->sum_all - summary->sum_all/1024; + + /* Next, walk through the histogram in decending order of hotness + and compute the statistics for the working set summary array. + As histogram entries are accumulated, we check to see which + working set entries have had their expected cum_value reached + and fill them in, walking the working set entries in increasing + size of cum_value. */ + ws_ix = 0; /* The current entry into the working set array. */ + cum = 0; /* The current accumulated counter sum. */ + count = 0; /* The current accumulated count of block counters. */ + for (h_ix = GCOV_HISTOGRAM_SIZE - 1; + h_ix >= 0 && ws_ix < NUM_GCOV_WORKING_SETS; h_ix--) + { + histo_bucket = &summary->histogram[h_ix]; + + /* If we haven't reached the required cumulative counter value for + the current working set percentage, simply accumulate this histogram + entry into the running sums and continue to the next histogram + entry. */ + if (cum + histo_bucket->cum_value < working_set_cum_values[ws_ix]) + { + cum += histo_bucket->cum_value; + count += histo_bucket->num_counters; + continue; + } + + /* If adding the current histogram entry's cumulative counter value + causes us to exceed the current working set size, then estimate + how many of this histogram entry's counter values are required to + reach the working set size, and fill in working set entries + as we reach their expected cumulative value. */ + for (c_num = 0, tmp_cum = cum; + c_num < histo_bucket->num_counters && ws_ix < NUM_GCOV_WORKING_SETS; + c_num++) + { + count++; + /* If we haven't reached the last histogram entry counter, add + in the minimum value again. This will underestimate the + cumulative sum so far, because many of the counter values in this + entry may have been larger than the minimum. We could add in the + average value every time, but that would require an expensive + divide operation. */ + if (c_num + 1 < histo_bucket->num_counters) + tmp_cum += histo_bucket->min_value; + /* If we have reached the last histogram entry counter, then add + in the entire cumulative value. */ + else + tmp_cum = cum + histo_bucket->cum_value; + + /* Next walk through successive working set entries and fill in + the statistics for any whose size we have reached by accumulating + this histogram counter. */ + while (ws_ix < NUM_GCOV_WORKING_SETS + && tmp_cum >= working_set_cum_values[ws_ix]) + { + gcov_working_sets[ws_ix].num_counters = count; + gcov_working_sets[ws_ix].min_counter + = histo_bucket->min_value; + ws_ix++; + } + } + /* Finally, update the running cumulative value since we were + using a temporary above. */ + cum += histo_bucket->cum_value; + } + gcc_assert (ws_ix == NUM_GCOV_WORKING_SETS); +} +#endif /* IN_GCOV <= 0 && !IN_LIBGCOV */ |