Enhances the gcov program summary by adding a histogram of arc counter

entries. This is used to compute working set information in the compiler
for use by optimizations that need information on hot vs cold counter
values or the rough working set size in terms of the number of counters.
Each working set data point is the minimum counter value and number of
counters required to reach a given percentage of the cumulative counter
sum across the profiled execution (sum_all in the program summary).

2012-09-04  Teresa Johnson  <tejohnson@google.com>

	* libgcc/libgcov.c (struct gcov_summary_buffer): New structure.
	(gcov_histogram_insert): New function.
	(gcov_compute_histogram): Ditto.
	(gcov_exit): Invoke gcov_compute_histogram, and perform merging of
	histograms during summary merging.
	* gcc/gcov-io.c (gcov_write_summary): Write out non-zero histogram
	entries to function summary along with an occupancy bit vector.
	(gcov_read_summary): Read in the histogram entries.
	(gcov_histo_index): New function.
	(void gcov_histogram_merge): Ditto.
	* gcc/gcov-io.h (gcov_type_unsigned): New type.
	(struct gcov_bucket_type): Ditto.
	(struct gcov_ctr_summary): Include histogram.
	(GCOV_TAG_SUMMARY_LENGTH): Update to include histogram entries.
	(GCOV_HISTOGRAM_SIZE): New macro.
	(GCOV_HISTOGRAM_BITVECTOR_SIZE): Ditto.
	* gcc/profile.c (NUM_GCOV_WORKING_SETS): Ditto.
	(gcov_working_sets): New global variable.
	(compute_working_sets): New function.
	(find_working_set): Ditto.
	(get_exec_counts): Invoke compute_working_sets.
	* gcc/coverage.c (read_counts_file): Merge histograms, and
	fix bug with accessing summary info for non-summable counters.
	* gcc/basic-block.h (gcov_type_unsigned): New type.
	(struct gcov_working_set_info): Ditto.
	(find_working_set): Declare.
	* gcc/gcov-dump.c (tag_summary): Dump out histogram.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@190952 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 14 insertions, 0 deletions

diff --git a/gcc/basic-block.h b/gcc/basic-block.h
index 09b5eb0a77c..288127f5660 100644
--- a/gcc/basic-block.h
+++ b/gcc/basic-block.h
@@ -31,6 +31,7 @@ along with GCC; see the file COPYING3.  If not see
    flow graph is manipulated by various optimizations.  A signed type
    makes those easy to detect.  */
 typedef HOST_WIDEST_INT gcov_type;
+typedef unsigned HOST_WIDEST_INT gcov_type_unsigned;
 
 /* Control flow edge information.  */
 struct GTY((user)) edge_def {
@@ -91,6 +92,16 @@ enum cfg_edge_flags {
    profile.c.  */
 extern const struct gcov_ctr_summary *profile_info;
 
+/* Working set size statistics for a given percentage of the entire
+   profile (sum_all from the counter summary).  */
+typedef struct gcov_working_set_info
+{
+  /* Number of hot counters included in this working set.  */
+  unsigned num_counters;
+  /* Smallest counter included in this working set.  */
+  gcov_type min_counter;
+} gcov_working_set_t;
+
 /* Declared in cfgloop.h.  */
 struct loop;
 
@@ -897,4 +908,7 @@ extern void rtl_profile_for_bb (basic_block);
 extern void rtl_profile_for_edge (edge);
 extern void default_rtl_profile (void);
 
+/* In profile.c.  */
+extern gcov_working_set_t *find_working_set(unsigned pct_times_10);
+
 #endif /* GCC_BASIC_BLOCK_H */