diff options
Diffstat (limited to 'gcc/gcov-io.c')
| -rw-r--r-- | gcc/gcov-io.c | 259 |
1 files changed, 255 insertions, 4 deletions
diff --git a/gcc/gcov-io.c b/gcc/gcov-io.c index 37c1c3e..d64fb42 100644 --- a/gcc/gcov-io.c +++ b/gcc/gcov-io.c @@ -368,10 +368,25 @@ gcov_write_tag_length (gcov_unsigned_t tag, gcov_unsigned_t length) GCOV_LINKAGE void gcov_write_summary (gcov_unsigned_t tag, const struct gcov_summary *summary) { - unsigned ix; + unsigned ix, h_ix, bv_ix, h_cnt = 0; const struct gcov_ctr_summary *csum; - - gcov_write_tag_length (tag, GCOV_TAG_SUMMARY_LENGTH); + unsigned histo_bitvector[GCOV_HISTOGRAM_BITVECTOR_SIZE]; + + /* Count number of non-zero histogram entries, and fill in a bit vector + of non-zero indices. The histogram is only currently computed for arc + counters. */ + for (bv_ix = 0; bv_ix < GCOV_HISTOGRAM_BITVECTOR_SIZE; bv_ix++) + histo_bitvector[bv_ix] = 0; + csum = &summary->ctrs[GCOV_COUNTER_ARCS]; + for (h_ix = 0; h_ix < GCOV_HISTOGRAM_SIZE; h_ix++) + { + if (csum->histogram[h_ix].num_counters > 0) + { + histo_bitvector[h_ix / 32] |= 1 << (h_ix % 32); + h_cnt++; + } + } + gcov_write_tag_length (tag, GCOV_TAG_SUMMARY_LENGTH(h_cnt)); gcov_write_unsigned (summary->checksum); for (csum = summary->ctrs, ix = GCOV_COUNTERS_SUMMABLE; ix--; csum++) { @@ -380,6 +395,22 @@ gcov_write_summary (gcov_unsigned_t tag, const struct gcov_summary *summary) gcov_write_counter (csum->sum_all); gcov_write_counter (csum->run_max); gcov_write_counter (csum->sum_max); + if (ix != GCOV_COUNTER_ARCS) + { + for (bv_ix = 0; bv_ix < GCOV_HISTOGRAM_BITVECTOR_SIZE; bv_ix++) + gcov_write_unsigned (0); + continue; + } + for (bv_ix = 0; bv_ix < GCOV_HISTOGRAM_BITVECTOR_SIZE; bv_ix++) + gcov_write_unsigned (histo_bitvector[bv_ix]); + for (h_ix = 0; h_ix < GCOV_HISTOGRAM_SIZE; h_ix++) + { + if (!csum->histogram[h_ix].num_counters) + continue; + gcov_write_unsigned (csum->histogram[h_ix].num_counters); + gcov_write_counter (csum->histogram[h_ix].min_value); + gcov_write_counter (csum->histogram[h_ix].cum_value); + } } } #endif /* IN_LIBGCOV */ @@ -488,8 +519,10 @@ gcov_read_string (void) GCOV_LINKAGE void gcov_read_summary (struct gcov_summary *summary) { - unsigned ix; + unsigned ix, h_ix, bv_ix, h_cnt = 0; struct gcov_ctr_summary *csum; + unsigned histo_bitvector[GCOV_HISTOGRAM_BITVECTOR_SIZE]; + unsigned cur_bitvector; summary->checksum = gcov_read_unsigned (); for (csum = summary->ctrs, ix = GCOV_COUNTERS_SUMMABLE; ix--; csum++) @@ -499,6 +532,43 @@ gcov_read_summary (struct gcov_summary *summary) csum->sum_all = gcov_read_counter (); csum->run_max = gcov_read_counter (); csum->sum_max = gcov_read_counter (); + memset (csum->histogram, 0, + sizeof (gcov_bucket_type) * GCOV_HISTOGRAM_SIZE); + for (bv_ix = 0; bv_ix < GCOV_HISTOGRAM_BITVECTOR_SIZE; bv_ix++) + { + histo_bitvector[bv_ix] = gcov_read_unsigned (); + h_cnt += __builtin_popcountll (histo_bitvector[bv_ix]); + } + bv_ix = 0; + h_ix = 0; + cur_bitvector = 0; + while (h_cnt--) + { + /* Find the index corresponding to the next entry we will read in. + First find the next non-zero bitvector and re-initialize + the histogram index accordingly, then right shift and increment + the index until we find a set bit. */ + while (!cur_bitvector) + { + h_ix = bv_ix * 32; + cur_bitvector = histo_bitvector[bv_ix++]; + gcc_assert(bv_ix <= GCOV_HISTOGRAM_BITVECTOR_SIZE); + } + while (!(cur_bitvector & 0x1)) + { + h_ix++; + cur_bitvector >>= 1; + } + gcc_assert(h_ix < GCOV_HISTOGRAM_SIZE); + + csum->histogram[h_ix].num_counters = gcov_read_unsigned (); + csum->histogram[h_ix].min_value = gcov_read_counter (); + csum->histogram[h_ix].cum_value = gcov_read_counter (); + /* Shift off the index we are done with and increment to the + corresponding next histogram entry. */ + cur_bitvector >>= 1; + h_ix++; + } } } @@ -550,3 +620,184 @@ gcov_time (void) return status.st_mtime; } #endif /* IN_GCOV */ + +#if IN_LIBGCOV || !IN_GCOV +/* Determine the index into histogram for VALUE. */ + +static unsigned +gcov_histo_index(gcov_type value) +{ + gcov_type_unsigned v = (gcov_type_unsigned)value; + unsigned r = 0; + unsigned prev2bits = 0; + + /* Find index into log2 scale histogram, where each of the log2 + sized buckets is divided into 4 linear sub-buckets for better + focus in the higher buckets. */ + + /* Find the place of the most-significant bit set. */ + if (v > 0) + r = 63 - __builtin_clzll (v); + + /* If at most the 2 least significant bits are set (value is + 0 - 3) then that value is our index into the lowest set of + four buckets. */ + if (r < 2) + return (unsigned)value; + + gcc_assert (r < 64); + + /* Find the two next most significant bits to determine which + of the four linear sub-buckets to select. */ + prev2bits = (v >> (r - 2)) & 0x3; + /* Finally, compose the final bucket index from the log2 index and + the next 2 bits. The minimum r value at this point is 2 since we + returned above if r was 2 or more, so the minimum bucket at this + point is 4. */ + return (r - 1) * 4 + prev2bits; +} + +/* Merge SRC_HISTO into TGT_HISTO. The counters are assumed to be in + the same relative order in both histograms, and are matched up + and merged in reverse order. Each counter is assigned an equal portion of + its entry's original cumulative counter value when computing the + new merged cum_value. */ + +static void gcov_histogram_merge(gcov_bucket_type *tgt_histo, + gcov_bucket_type *src_histo) +{ + int src_i, tgt_i, tmp_i = 0; + unsigned src_num, tgt_num, merge_num; + gcov_type src_cum, tgt_cum, merge_src_cum, merge_tgt_cum, merge_cum; + gcov_type merge_min; + gcov_bucket_type tmp_histo[GCOV_HISTOGRAM_SIZE]; + int src_done = 0; + + memset(tmp_histo, 0, sizeof (gcov_bucket_type) * GCOV_HISTOGRAM_SIZE); + + /* Assume that the counters are in the same relative order in both + histograms. Walk the histograms from largest to smallest entry, + matching up and combining counters in order. */ + src_num = 0; + src_cum = 0; + src_i = GCOV_HISTOGRAM_SIZE - 1; + for (tgt_i = GCOV_HISTOGRAM_SIZE - 1; tgt_i >= 0 && !src_done; tgt_i--) + { + tgt_num = tgt_histo[tgt_i].num_counters; + tgt_cum = tgt_histo[tgt_i].cum_value; + /* Keep going until all of the target histogram's counters at this + position have been matched and merged with counters from the + source histogram. */ + while (tgt_num > 0 && !src_done) + { + /* If this is either the first time through this loop or we just + exhausted the previous non-zero source histogram entry, look + for the next non-zero source histogram entry. */ + if (!src_num) + { + /* Locate the next non-zero entry. */ + while (src_i >= 0 && !src_histo[src_i].num_counters) + src_i--; + /* If source histogram has fewer counters, then just copy over the + remaining target counters and quit. */ + if (src_i < 0) + { + tmp_histo[tgt_i].num_counters += tgt_num; + tmp_histo[tgt_i].cum_value += tgt_cum; + if (!tmp_histo[tgt_i].min_value || + tgt_histo[tgt_i].min_value < tmp_histo[tgt_i].min_value) + tmp_histo[tgt_i].min_value = tgt_histo[tgt_i].min_value; + while (--tgt_i >= 0) + { + tmp_histo[tgt_i].num_counters + += tgt_histo[tgt_i].num_counters; + tmp_histo[tgt_i].cum_value += tgt_histo[tgt_i].cum_value; + if (!tmp_histo[tgt_i].min_value || + tgt_histo[tgt_i].min_value + < tmp_histo[tgt_i].min_value) + tmp_histo[tgt_i].min_value = tgt_histo[tgt_i].min_value; + } + + src_done = 1; + break; + } + + src_num = src_histo[src_i].num_counters; + src_cum = src_histo[src_i].cum_value; + } + + /* The number of counters to merge on this pass is the minimum + of the remaining counters from the current target and source + histogram entries. */ + merge_num = tgt_num; + if (src_num < merge_num) + merge_num = src_num; + + /* The merged min_value is the sum of the min_values from target + and source. */ + merge_min = tgt_histo[tgt_i].min_value + src_histo[src_i].min_value; + + /* Compute the portion of source and target entries' cum_value + that will be apportioned to the counters being merged. + The total remaining cum_value from each entry is divided + equally among the counters from that histogram entry if we + are not merging all of them. */ + merge_src_cum = src_cum; + if (merge_num < src_num) + merge_src_cum = merge_num * src_cum / src_num; + merge_tgt_cum = tgt_cum; + if (merge_num < tgt_num) + merge_tgt_cum = merge_num * tgt_cum / tgt_num; + /* The merged cum_value is the sum of the source and target + components. */ + merge_cum = merge_src_cum + merge_tgt_cum; + + /* Update the remaining number of counters and cum_value left + to be merged from this source and target entry. */ + src_cum -= merge_src_cum; + tgt_cum -= merge_tgt_cum; + src_num -= merge_num; + tgt_num -= merge_num; + + /* The merged counters get placed in the new merged histogram + at the entry for the merged min_value. */ + tmp_i = gcov_histo_index(merge_min); + gcc_assert (tmp_i < GCOV_HISTOGRAM_SIZE); + tmp_histo[tmp_i].num_counters += merge_num; + tmp_histo[tmp_i].cum_value += merge_cum; + if (!tmp_histo[tmp_i].min_value || + merge_min < tmp_histo[tmp_i].min_value) + tmp_histo[tmp_i].min_value = merge_min; + + /* Ensure the search for the next non-zero src_histo entry starts + at the next smallest histogram bucket. */ + if (!src_num) + src_i--; + } + } + + gcc_assert (tgt_i < 0); + + /* In the case where there were more counters in the source histogram, + accumulate the remaining unmerged cumulative counter values. Add + those to the smallest non-zero target histogram entry. Otherwise, + the total cumulative counter values in the histogram will be smaller + than the sum_all stored in the summary, which will complicate + computing the working set information from the histogram later on. */ + if (src_num) + src_i--; + while (src_i >= 0) + { + src_cum += src_histo[src_i].cum_value; + src_i--; + } + /* At this point, tmp_i should be the smallest non-zero entry in the + tmp_histo. */ + gcc_assert(tmp_i >= 0 && tmp_i < GCOV_HISTOGRAM_SIZE + && tmp_histo[tmp_i].num_counters > 0); + tmp_histo[tmp_i].cum_value += src_cum; + + /* Finally, copy the merged histogram into tgt_histo. */ + memcpy(tgt_histo, tmp_histo, sizeof (gcov_bucket_type) * GCOV_HISTOGRAM_SIZE); +} +#endif /* IN_LIBGCOV || !IN_GCOV */ |