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1235 lines
34 KiB
C
1235 lines
34 KiB
C
/* Calculate branch probabilities, and basic block execution counts.
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Copyright (C) 1990, 1991, 1992, 1993, 1994, 1996, 1997, 1998, 1999,
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2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
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Contributed by James E. Wilson, UC Berkeley/Cygnus Support;
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based on some ideas from Dain Samples of UC Berkeley.
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Further mangling by Bob Manson, Cygnus Support.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to the Free
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Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301, USA. */
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/* Generate basic block profile instrumentation and auxiliary files.
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Profile generation is optimized, so that not all arcs in the basic
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block graph need instrumenting. First, the BB graph is closed with
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one entry (function start), and one exit (function exit). Any
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ABNORMAL_EDGE cannot be instrumented (because there is no control
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path to place the code). We close the graph by inserting fake
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EDGE_FAKE edges to the EXIT_BLOCK, from the sources of abnormal
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edges that do not go to the exit_block. We ignore such abnormal
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edges. Naturally these fake edges are never directly traversed,
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and so *cannot* be directly instrumented. Some other graph
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massaging is done. To optimize the instrumentation we generate the
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BB minimal span tree, only edges that are not on the span tree
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(plus the entry point) need instrumenting. From that information
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all other edge counts can be deduced. By construction all fake
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edges must be on the spanning tree. We also attempt to place
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EDGE_CRITICAL edges on the spanning tree.
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The auxiliary files generated are <dumpbase>.gcno (at compile time)
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and <dumpbase>.gcda (at run time). The format is
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described in full in gcov-io.h. */
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/* ??? Register allocation should use basic block execution counts to
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give preference to the most commonly executed blocks. */
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/* ??? Should calculate branch probabilities before instrumenting code, since
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then we can use arc counts to help decide which arcs to instrument. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "rtl.h"
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#include "flags.h"
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#include "output.h"
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#include "regs.h"
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#include "expr.h"
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#include "function.h"
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#include "toplev.h"
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#include "coverage.h"
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#include "value-prof.h"
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#include "tree.h"
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#include "cfghooks.h"
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#include "tree-flow.h"
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#include "timevar.h"
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#include "cfgloop.h"
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#include "tree-pass.h"
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/* Hooks for profiling. */
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static struct profile_hooks* profile_hooks;
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/* Additional information about the edges we need. */
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struct edge_info {
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unsigned int count_valid : 1;
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/* Is on the spanning tree. */
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unsigned int on_tree : 1;
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/* Pretend this edge does not exist (it is abnormal and we've
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inserted a fake to compensate). */
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unsigned int ignore : 1;
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};
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struct bb_info {
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unsigned int count_valid : 1;
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/* Number of successor and predecessor edges. */
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gcov_type succ_count;
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gcov_type pred_count;
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};
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#define EDGE_INFO(e) ((struct edge_info *) (e)->aux)
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#define BB_INFO(b) ((struct bb_info *) (b)->aux)
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/* Counter summary from the last set of coverage counts read. */
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const struct gcov_ctr_summary *profile_info;
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/* Collect statistics on the performance of this pass for the entire source
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file. */
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static int total_num_blocks;
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static int total_num_edges;
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static int total_num_edges_ignored;
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static int total_num_edges_instrumented;
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static int total_num_blocks_created;
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static int total_num_passes;
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static int total_num_times_called;
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static int total_hist_br_prob[20];
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static int total_num_never_executed;
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static int total_num_branches;
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/* Forward declarations. */
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static void find_spanning_tree (struct edge_list *);
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static unsigned instrument_edges (struct edge_list *);
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static void instrument_values (histogram_values);
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static void compute_branch_probabilities (void);
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static void compute_value_histograms (histogram_values);
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static gcov_type * get_exec_counts (void);
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static basic_block find_group (basic_block);
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static void union_groups (basic_block, basic_block);
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/* Add edge instrumentation code to the entire insn chain.
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F is the first insn of the chain.
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NUM_BLOCKS is the number of basic blocks found in F. */
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static unsigned
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instrument_edges (struct edge_list *el)
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{
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unsigned num_instr_edges = 0;
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int num_edges = NUM_EDGES (el);
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basic_block bb;
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FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
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{
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edge e;
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edge_iterator ei;
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FOR_EACH_EDGE (e, ei, bb->succs)
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{
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struct edge_info *inf = EDGE_INFO (e);
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if (!inf->ignore && !inf->on_tree)
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{
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gcc_assert (!(e->flags & EDGE_ABNORMAL));
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if (dump_file)
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fprintf (dump_file, "Edge %d to %d instrumented%s\n",
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e->src->index, e->dest->index,
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EDGE_CRITICAL_P (e) ? " (and split)" : "");
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(profile_hooks->gen_edge_profiler) (num_instr_edges++, e);
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}
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}
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}
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total_num_blocks_created += num_edges;
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if (dump_file)
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fprintf (dump_file, "%d edges instrumented\n", num_instr_edges);
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return num_instr_edges;
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}
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/* Add code to measure histograms for values in list VALUES. */
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static void
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instrument_values (histogram_values values)
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{
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unsigned i, t;
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/* Emit code to generate the histograms before the insns. */
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for (i = 0; i < VEC_length (histogram_value, values); i++)
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{
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histogram_value hist = VEC_index (histogram_value, values, i);
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switch (hist->type)
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{
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case HIST_TYPE_INTERVAL:
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t = GCOV_COUNTER_V_INTERVAL;
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break;
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case HIST_TYPE_POW2:
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t = GCOV_COUNTER_V_POW2;
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break;
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case HIST_TYPE_SINGLE_VALUE:
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t = GCOV_COUNTER_V_SINGLE;
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break;
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case HIST_TYPE_CONST_DELTA:
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t = GCOV_COUNTER_V_DELTA;
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break;
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default:
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gcc_unreachable ();
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}
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if (!coverage_counter_alloc (t, hist->n_counters))
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continue;
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switch (hist->type)
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{
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case HIST_TYPE_INTERVAL:
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(profile_hooks->gen_interval_profiler) (hist, t, 0);
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break;
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case HIST_TYPE_POW2:
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(profile_hooks->gen_pow2_profiler) (hist, t, 0);
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break;
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case HIST_TYPE_SINGLE_VALUE:
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(profile_hooks->gen_one_value_profiler) (hist, t, 0);
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break;
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case HIST_TYPE_CONST_DELTA:
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(profile_hooks->gen_const_delta_profiler) (hist, t, 0);
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break;
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default:
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gcc_unreachable ();
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}
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}
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}
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/* Computes hybrid profile for all matching entries in da_file. */
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static gcov_type *
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get_exec_counts (void)
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{
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unsigned num_edges = 0;
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basic_block bb;
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gcov_type *counts;
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/* Count the edges to be (possibly) instrumented. */
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FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
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{
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edge e;
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edge_iterator ei;
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FOR_EACH_EDGE (e, ei, bb->succs)
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if (!EDGE_INFO (e)->ignore && !EDGE_INFO (e)->on_tree)
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num_edges++;
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}
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counts = get_coverage_counts (GCOV_COUNTER_ARCS, num_edges, &profile_info);
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if (!counts)
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return NULL;
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if (dump_file && profile_info)
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fprintf(dump_file, "Merged %u profiles with maximal count %u.\n",
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profile_info->runs, (unsigned) profile_info->sum_max);
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return counts;
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}
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/* Compute the branch probabilities for the various branches.
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Annotate them accordingly. */
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static void
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compute_branch_probabilities (void)
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{
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basic_block bb;
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int i;
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int num_edges = 0;
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int changes;
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int passes;
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int hist_br_prob[20];
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int num_never_executed;
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int num_branches;
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gcov_type *exec_counts = get_exec_counts ();
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int exec_counts_pos = 0;
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/* Very simple sanity checks so we catch bugs in our profiling code. */
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if (profile_info)
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{
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if (profile_info->run_max * profile_info->runs < profile_info->sum_max)
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{
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error ("corrupted profile info: run_max * runs < sum_max");
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exec_counts = NULL;
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}
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if (profile_info->sum_all < profile_info->sum_max)
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{
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error ("corrupted profile info: sum_all is smaller than sum_max");
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exec_counts = NULL;
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}
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}
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/* Attach extra info block to each bb. */
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alloc_aux_for_blocks (sizeof (struct bb_info));
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FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
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{
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edge e;
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edge_iterator ei;
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FOR_EACH_EDGE (e, ei, bb->succs)
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if (!EDGE_INFO (e)->ignore)
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BB_INFO (bb)->succ_count++;
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FOR_EACH_EDGE (e, ei, bb->preds)
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if (!EDGE_INFO (e)->ignore)
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BB_INFO (bb)->pred_count++;
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}
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/* Avoid predicting entry on exit nodes. */
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BB_INFO (EXIT_BLOCK_PTR)->succ_count = 2;
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BB_INFO (ENTRY_BLOCK_PTR)->pred_count = 2;
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/* For each edge not on the spanning tree, set its execution count from
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the .da file. */
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/* The first count in the .da file is the number of times that the function
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was entered. This is the exec_count for block zero. */
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FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
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{
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edge e;
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edge_iterator ei;
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FOR_EACH_EDGE (e, ei, bb->succs)
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if (!EDGE_INFO (e)->ignore && !EDGE_INFO (e)->on_tree)
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{
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num_edges++;
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if (exec_counts)
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{
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e->count = exec_counts[exec_counts_pos++];
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if (e->count > profile_info->sum_max)
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{
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error ("corrupted profile info: edge from %i to %i exceeds maximal count",
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bb->index, e->dest->index);
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}
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}
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else
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e->count = 0;
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EDGE_INFO (e)->count_valid = 1;
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BB_INFO (bb)->succ_count--;
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BB_INFO (e->dest)->pred_count--;
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if (dump_file)
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{
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fprintf (dump_file, "\nRead edge from %i to %i, count:",
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bb->index, e->dest->index);
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fprintf (dump_file, HOST_WIDEST_INT_PRINT_DEC,
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(HOST_WIDEST_INT) e->count);
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}
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}
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}
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if (dump_file)
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fprintf (dump_file, "\n%d edge counts read\n", num_edges);
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/* For every block in the file,
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- if every exit/entrance edge has a known count, then set the block count
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- if the block count is known, and every exit/entrance edge but one has
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a known execution count, then set the count of the remaining edge
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As edge counts are set, decrement the succ/pred count, but don't delete
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the edge, that way we can easily tell when all edges are known, or only
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one edge is unknown. */
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/* The order that the basic blocks are iterated through is important.
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Since the code that finds spanning trees starts with block 0, low numbered
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edges are put on the spanning tree in preference to high numbered edges.
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Hence, most instrumented edges are at the end. Graph solving works much
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faster if we propagate numbers from the end to the start.
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This takes an average of slightly more than 3 passes. */
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changes = 1;
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passes = 0;
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while (changes)
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{
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passes++;
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changes = 0;
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FOR_BB_BETWEEN (bb, EXIT_BLOCK_PTR, NULL, prev_bb)
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{
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struct bb_info *bi = BB_INFO (bb);
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if (! bi->count_valid)
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{
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if (bi->succ_count == 0)
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{
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edge e;
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edge_iterator ei;
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gcov_type total = 0;
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FOR_EACH_EDGE (e, ei, bb->succs)
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total += e->count;
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bb->count = total;
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bi->count_valid = 1;
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changes = 1;
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}
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else if (bi->pred_count == 0)
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{
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edge e;
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edge_iterator ei;
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gcov_type total = 0;
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FOR_EACH_EDGE (e, ei, bb->preds)
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total += e->count;
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bb->count = total;
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bi->count_valid = 1;
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changes = 1;
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}
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}
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if (bi->count_valid)
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{
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if (bi->succ_count == 1)
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{
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edge e;
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edge_iterator ei;
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gcov_type total = 0;
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/* One of the counts will be invalid, but it is zero,
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so adding it in also doesn't hurt. */
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FOR_EACH_EDGE (e, ei, bb->succs)
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total += e->count;
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/* Seedgeh for the invalid edge, and set its count. */
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FOR_EACH_EDGE (e, ei, bb->succs)
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if (! EDGE_INFO (e)->count_valid && ! EDGE_INFO (e)->ignore)
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break;
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/* Calculate count for remaining edge by conservation. */
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total = bb->count - total;
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gcc_assert (e);
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EDGE_INFO (e)->count_valid = 1;
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e->count = total;
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bi->succ_count--;
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BB_INFO (e->dest)->pred_count--;
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changes = 1;
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}
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if (bi->pred_count == 1)
|
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{
|
||
edge e;
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edge_iterator ei;
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gcov_type total = 0;
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||
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/* One of the counts will be invalid, but it is zero,
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||
so adding it in also doesn't hurt. */
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FOR_EACH_EDGE (e, ei, bb->preds)
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total += e->count;
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|
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/* Search for the invalid edge, and set its count. */
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FOR_EACH_EDGE (e, ei, bb->preds)
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if (!EDGE_INFO (e)->count_valid && !EDGE_INFO (e)->ignore)
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break;
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||
|
||
/* Calculate count for remaining edge by conservation. */
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||
total = bb->count - total + e->count;
|
||
|
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gcc_assert (e);
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EDGE_INFO (e)->count_valid = 1;
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||
e->count = total;
|
||
bi->pred_count--;
|
||
|
||
BB_INFO (e->src)->succ_count--;
|
||
changes = 1;
|
||
}
|
||
}
|
||
}
|
||
}
|
||
if (dump_file)
|
||
dump_flow_info (dump_file, dump_flags);
|
||
|
||
total_num_passes += passes;
|
||
if (dump_file)
|
||
fprintf (dump_file, "Graph solving took %d passes.\n\n", passes);
|
||
|
||
/* If the graph has been correctly solved, every block will have a
|
||
succ and pred count of zero. */
|
||
FOR_EACH_BB (bb)
|
||
{
|
||
gcc_assert (!BB_INFO (bb)->succ_count && !BB_INFO (bb)->pred_count);
|
||
}
|
||
|
||
/* For every edge, calculate its branch probability and add a reg_note
|
||
to the branch insn to indicate this. */
|
||
|
||
for (i = 0; i < 20; i++)
|
||
hist_br_prob[i] = 0;
|
||
num_never_executed = 0;
|
||
num_branches = 0;
|
||
|
||
FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
|
||
{
|
||
edge e;
|
||
edge_iterator ei;
|
||
|
||
if (bb->count < 0)
|
||
{
|
||
error ("corrupted profile info: number of iterations for basic block %d thought to be %i",
|
||
bb->index, (int)bb->count);
|
||
bb->count = 0;
|
||
}
|
||
FOR_EACH_EDGE (e, ei, bb->succs)
|
||
{
|
||
/* Function may return twice in the cased the called function is
|
||
setjmp or calls fork, but we can't represent this by extra
|
||
edge from the entry, since extra edge from the exit is
|
||
already present. We get negative frequency from the entry
|
||
point. */
|
||
if ((e->count < 0
|
||
&& e->dest == EXIT_BLOCK_PTR)
|
||
|| (e->count > bb->count
|
||
&& e->dest != EXIT_BLOCK_PTR))
|
||
{
|
||
if (block_ends_with_call_p (bb))
|
||
e->count = e->count < 0 ? 0 : bb->count;
|
||
}
|
||
if (e->count < 0 || e->count > bb->count)
|
||
{
|
||
error ("corrupted profile info: number of executions for edge %d-%d thought to be %i",
|
||
e->src->index, e->dest->index,
|
||
(int)e->count);
|
||
e->count = bb->count / 2;
|
||
}
|
||
}
|
||
if (bb->count)
|
||
{
|
||
FOR_EACH_EDGE (e, ei, bb->succs)
|
||
e->probability = (e->count * REG_BR_PROB_BASE + bb->count / 2) / bb->count;
|
||
if (bb->index >= NUM_FIXED_BLOCKS
|
||
&& block_ends_with_condjump_p (bb)
|
||
&& EDGE_COUNT (bb->succs) >= 2)
|
||
{
|
||
int prob;
|
||
edge e;
|
||
int index;
|
||
|
||
/* Find the branch edge. It is possible that we do have fake
|
||
edges here. */
|
||
FOR_EACH_EDGE (e, ei, bb->succs)
|
||
if (!(e->flags & (EDGE_FAKE | EDGE_FALLTHRU)))
|
||
break;
|
||
|
||
prob = e->probability;
|
||
index = prob * 20 / REG_BR_PROB_BASE;
|
||
|
||
if (index == 20)
|
||
index = 19;
|
||
hist_br_prob[index]++;
|
||
|
||
num_branches++;
|
||
}
|
||
}
|
||
/* As a last resort, distribute the probabilities evenly.
|
||
Use simple heuristics that if there are normal edges,
|
||
give all abnormals frequency of 0, otherwise distribute the
|
||
frequency over abnormals (this is the case of noreturn
|
||
calls). */
|
||
else if (profile_status == PROFILE_ABSENT)
|
||
{
|
||
int total = 0;
|
||
|
||
FOR_EACH_EDGE (e, ei, bb->succs)
|
||
if (!(e->flags & (EDGE_COMPLEX | EDGE_FAKE)))
|
||
total ++;
|
||
if (total)
|
||
{
|
||
FOR_EACH_EDGE (e, ei, bb->succs)
|
||
if (!(e->flags & (EDGE_COMPLEX | EDGE_FAKE)))
|
||
e->probability = REG_BR_PROB_BASE / total;
|
||
else
|
||
e->probability = 0;
|
||
}
|
||
else
|
||
{
|
||
total += EDGE_COUNT (bb->succs);
|
||
FOR_EACH_EDGE (e, ei, bb->succs)
|
||
e->probability = REG_BR_PROB_BASE / total;
|
||
}
|
||
if (bb->index >= NUM_FIXED_BLOCKS
|
||
&& block_ends_with_condjump_p (bb)
|
||
&& EDGE_COUNT (bb->succs) >= 2)
|
||
num_branches++, num_never_executed;
|
||
}
|
||
}
|
||
counts_to_freqs ();
|
||
|
||
if (dump_file)
|
||
{
|
||
fprintf (dump_file, "%d branches\n", num_branches);
|
||
fprintf (dump_file, "%d branches never executed\n",
|
||
num_never_executed);
|
||
if (num_branches)
|
||
for (i = 0; i < 10; i++)
|
||
fprintf (dump_file, "%d%% branches in range %d-%d%%\n",
|
||
(hist_br_prob[i] + hist_br_prob[19-i]) * 100 / num_branches,
|
||
5 * i, 5 * i + 5);
|
||
|
||
total_num_branches += num_branches;
|
||
total_num_never_executed += num_never_executed;
|
||
for (i = 0; i < 20; i++)
|
||
total_hist_br_prob[i] += hist_br_prob[i];
|
||
|
||
fputc ('\n', dump_file);
|
||
fputc ('\n', dump_file);
|
||
}
|
||
|
||
free_aux_for_blocks ();
|
||
}
|
||
|
||
/* Load value histograms values whose description is stored in VALUES array
|
||
from .gcda file. */
|
||
|
||
static void
|
||
compute_value_histograms (histogram_values values)
|
||
{
|
||
unsigned i, j, t, any;
|
||
unsigned n_histogram_counters[GCOV_N_VALUE_COUNTERS];
|
||
gcov_type *histogram_counts[GCOV_N_VALUE_COUNTERS];
|
||
gcov_type *act_count[GCOV_N_VALUE_COUNTERS];
|
||
gcov_type *aact_count;
|
||
|
||
for (t = 0; t < GCOV_N_VALUE_COUNTERS; t++)
|
||
n_histogram_counters[t] = 0;
|
||
|
||
for (i = 0; i < VEC_length (histogram_value, values); i++)
|
||
{
|
||
histogram_value hist = VEC_index (histogram_value, values, i);
|
||
n_histogram_counters[(int) hist->type] += hist->n_counters;
|
||
}
|
||
|
||
any = 0;
|
||
for (t = 0; t < GCOV_N_VALUE_COUNTERS; t++)
|
||
{
|
||
if (!n_histogram_counters[t])
|
||
{
|
||
histogram_counts[t] = NULL;
|
||
continue;
|
||
}
|
||
|
||
histogram_counts[t] =
|
||
get_coverage_counts (COUNTER_FOR_HIST_TYPE (t),
|
||
n_histogram_counters[t], NULL);
|
||
if (histogram_counts[t])
|
||
any = 1;
|
||
act_count[t] = histogram_counts[t];
|
||
}
|
||
if (!any)
|
||
return;
|
||
|
||
for (i = 0; i < VEC_length (histogram_value, values); i++)
|
||
{
|
||
histogram_value hist = VEC_index (histogram_value, values, i);
|
||
tree stmt = hist->hvalue.stmt;
|
||
stmt_ann_t ann = get_stmt_ann (stmt);
|
||
|
||
t = (int) hist->type;
|
||
|
||
aact_count = act_count[t];
|
||
act_count[t] += hist->n_counters;
|
||
|
||
hist->hvalue.next = ann->histograms;
|
||
ann->histograms = hist;
|
||
hist->hvalue.counters = XNEWVEC (gcov_type, hist->n_counters);
|
||
for (j = 0; j < hist->n_counters; j++)
|
||
hist->hvalue.counters[j] = aact_count[j];
|
||
}
|
||
|
||
for (t = 0; t < GCOV_N_VALUE_COUNTERS; t++)
|
||
if (histogram_counts[t])
|
||
free (histogram_counts[t]);
|
||
}
|
||
|
||
/* The entry basic block will be moved around so that it has index=1,
|
||
there is nothing at index 0 and the exit is at n_basic_block. */
|
||
#define BB_TO_GCOV_INDEX(bb) ((bb)->index - 1)
|
||
/* When passed NULL as file_name, initialize.
|
||
When passed something else, output the necessary commands to change
|
||
line to LINE and offset to FILE_NAME. */
|
||
static void
|
||
output_location (char const *file_name, int line,
|
||
gcov_position_t *offset, basic_block bb)
|
||
{
|
||
static char const *prev_file_name;
|
||
static int prev_line;
|
||
bool name_differs, line_differs;
|
||
|
||
if (!file_name)
|
||
{
|
||
prev_file_name = NULL;
|
||
prev_line = -1;
|
||
return;
|
||
}
|
||
|
||
name_differs = !prev_file_name || strcmp (file_name, prev_file_name);
|
||
line_differs = prev_line != line;
|
||
|
||
if (name_differs || line_differs)
|
||
{
|
||
if (!*offset)
|
||
{
|
||
*offset = gcov_write_tag (GCOV_TAG_LINES);
|
||
gcov_write_unsigned (BB_TO_GCOV_INDEX (bb));
|
||
name_differs = line_differs=true;
|
||
}
|
||
|
||
/* If this is a new source file, then output the
|
||
file's name to the .bb file. */
|
||
if (name_differs)
|
||
{
|
||
prev_file_name = file_name;
|
||
gcov_write_unsigned (0);
|
||
gcov_write_string (prev_file_name);
|
||
}
|
||
if (line_differs)
|
||
{
|
||
gcov_write_unsigned (line);
|
||
prev_line = line;
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Instrument and/or analyze program behavior based on program flow graph.
|
||
In either case, this function builds a flow graph for the function being
|
||
compiled. The flow graph is stored in BB_GRAPH.
|
||
|
||
When FLAG_PROFILE_ARCS is nonzero, this function instruments the edges in
|
||
the flow graph that are needed to reconstruct the dynamic behavior of the
|
||
flow graph.
|
||
|
||
When FLAG_BRANCH_PROBABILITIES is nonzero, this function reads auxiliary
|
||
information from a data file containing edge count information from previous
|
||
executions of the function being compiled. In this case, the flow graph is
|
||
annotated with actual execution counts, which are later propagated into the
|
||
rtl for optimization purposes.
|
||
|
||
Main entry point of this file. */
|
||
|
||
void
|
||
branch_prob (void)
|
||
{
|
||
basic_block bb;
|
||
unsigned i;
|
||
unsigned num_edges, ignored_edges;
|
||
unsigned num_instrumented;
|
||
struct edge_list *el;
|
||
histogram_values values = NULL;
|
||
|
||
total_num_times_called++;
|
||
|
||
flow_call_edges_add (NULL);
|
||
add_noreturn_fake_exit_edges ();
|
||
|
||
/* We can't handle cyclic regions constructed using abnormal edges.
|
||
To avoid these we replace every source of abnormal edge by a fake
|
||
edge from entry node and every destination by fake edge to exit.
|
||
This keeps graph acyclic and our calculation exact for all normal
|
||
edges except for exit and entrance ones.
|
||
|
||
We also add fake exit edges for each call and asm statement in the
|
||
basic, since it may not return. */
|
||
|
||
FOR_EACH_BB (bb)
|
||
{
|
||
int need_exit_edge = 0, need_entry_edge = 0;
|
||
int have_exit_edge = 0, have_entry_edge = 0;
|
||
edge e;
|
||
edge_iterator ei;
|
||
|
||
/* Functions returning multiple times are not handled by extra edges.
|
||
Instead we simply allow negative counts on edges from exit to the
|
||
block past call and corresponding probabilities. We can't go
|
||
with the extra edges because that would result in flowgraph that
|
||
needs to have fake edges outside the spanning tree. */
|
||
|
||
FOR_EACH_EDGE (e, ei, bb->succs)
|
||
{
|
||
block_stmt_iterator bsi;
|
||
tree last = NULL;
|
||
|
||
/* It may happen that there are compiler generated statements
|
||
without a locus at all. Go through the basic block from the
|
||
last to the first statement looking for a locus. */
|
||
for (bsi = bsi_last (bb); !bsi_end_p (bsi); bsi_prev (&bsi))
|
||
{
|
||
last = bsi_stmt (bsi);
|
||
if (EXPR_LOCUS (last))
|
||
break;
|
||
}
|
||
|
||
/* Edge with goto locus might get wrong coverage info unless
|
||
it is the only edge out of BB.
|
||
Don't do that when the locuses match, so
|
||
if (blah) goto something;
|
||
is not computed twice. */
|
||
if (last && EXPR_LOCUS (last)
|
||
&& e->goto_locus
|
||
&& !single_succ_p (bb)
|
||
#ifdef USE_MAPPED_LOCATION
|
||
&& (LOCATION_FILE (e->goto_locus)
|
||
!= LOCATION_FILE (EXPR_LOCATION (last))
|
||
|| (LOCATION_LINE (e->goto_locus)
|
||
!= LOCATION_LINE (EXPR_LOCATION (last)))))
|
||
#else
|
||
&& (e->goto_locus->file != EXPR_LOCUS (last)->file
|
||
|| (e->goto_locus->line != EXPR_LOCUS (last)->line)))
|
||
#endif
|
||
{
|
||
basic_block new = split_edge (e);
|
||
single_succ_edge (new)->goto_locus = e->goto_locus;
|
||
}
|
||
if ((e->flags & (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL))
|
||
&& e->dest != EXIT_BLOCK_PTR)
|
||
need_exit_edge = 1;
|
||
if (e->dest == EXIT_BLOCK_PTR)
|
||
have_exit_edge = 1;
|
||
}
|
||
FOR_EACH_EDGE (e, ei, bb->preds)
|
||
{
|
||
if ((e->flags & (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL))
|
||
&& e->src != ENTRY_BLOCK_PTR)
|
||
need_entry_edge = 1;
|
||
if (e->src == ENTRY_BLOCK_PTR)
|
||
have_entry_edge = 1;
|
||
}
|
||
|
||
if (need_exit_edge && !have_exit_edge)
|
||
{
|
||
if (dump_file)
|
||
fprintf (dump_file, "Adding fake exit edge to bb %i\n",
|
||
bb->index);
|
||
make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
|
||
}
|
||
if (need_entry_edge && !have_entry_edge)
|
||
{
|
||
if (dump_file)
|
||
fprintf (dump_file, "Adding fake entry edge to bb %i\n",
|
||
bb->index);
|
||
make_edge (ENTRY_BLOCK_PTR, bb, EDGE_FAKE);
|
||
}
|
||
}
|
||
|
||
el = create_edge_list ();
|
||
num_edges = NUM_EDGES (el);
|
||
alloc_aux_for_edges (sizeof (struct edge_info));
|
||
|
||
/* The basic blocks are expected to be numbered sequentially. */
|
||
compact_blocks ();
|
||
|
||
ignored_edges = 0;
|
||
for (i = 0 ; i < num_edges ; i++)
|
||
{
|
||
edge e = INDEX_EDGE (el, i);
|
||
e->count = 0;
|
||
|
||
/* Mark edges we've replaced by fake edges above as ignored. */
|
||
if ((e->flags & (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL))
|
||
&& e->src != ENTRY_BLOCK_PTR && e->dest != EXIT_BLOCK_PTR)
|
||
{
|
||
EDGE_INFO (e)->ignore = 1;
|
||
ignored_edges++;
|
||
}
|
||
}
|
||
|
||
/* Create spanning tree from basic block graph, mark each edge that is
|
||
on the spanning tree. We insert as many abnormal and critical edges
|
||
as possible to minimize number of edge splits necessary. */
|
||
|
||
find_spanning_tree (el);
|
||
|
||
/* Fake edges that are not on the tree will not be instrumented, so
|
||
mark them ignored. */
|
||
for (num_instrumented = i = 0; i < num_edges; i++)
|
||
{
|
||
edge e = INDEX_EDGE (el, i);
|
||
struct edge_info *inf = EDGE_INFO (e);
|
||
|
||
if (inf->ignore || inf->on_tree)
|
||
/*NOP*/;
|
||
else if (e->flags & EDGE_FAKE)
|
||
{
|
||
inf->ignore = 1;
|
||
ignored_edges++;
|
||
}
|
||
else
|
||
num_instrumented++;
|
||
}
|
||
|
||
total_num_blocks += n_basic_blocks;
|
||
if (dump_file)
|
||
fprintf (dump_file, "%d basic blocks\n", n_basic_blocks);
|
||
|
||
total_num_edges += num_edges;
|
||
if (dump_file)
|
||
fprintf (dump_file, "%d edges\n", num_edges);
|
||
|
||
total_num_edges_ignored += ignored_edges;
|
||
if (dump_file)
|
||
fprintf (dump_file, "%d ignored edges\n", ignored_edges);
|
||
|
||
/* Write the data from which gcov can reconstruct the basic block
|
||
graph. */
|
||
|
||
/* Basic block flags */
|
||
if (coverage_begin_output ())
|
||
{
|
||
gcov_position_t offset;
|
||
|
||
offset = gcov_write_tag (GCOV_TAG_BLOCKS);
|
||
for (i = 0; i != (unsigned) (n_basic_blocks); i++)
|
||
gcov_write_unsigned (0);
|
||
gcov_write_length (offset);
|
||
}
|
||
|
||
/* Keep all basic block indexes nonnegative in the gcov output.
|
||
Index 0 is used for entry block, last index is for exit block.
|
||
*/
|
||
ENTRY_BLOCK_PTR->index = 1;
|
||
EXIT_BLOCK_PTR->index = last_basic_block;
|
||
|
||
/* Arcs */
|
||
if (coverage_begin_output ())
|
||
{
|
||
gcov_position_t offset;
|
||
|
||
FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, EXIT_BLOCK_PTR, next_bb)
|
||
{
|
||
edge e;
|
||
edge_iterator ei;
|
||
|
||
offset = gcov_write_tag (GCOV_TAG_ARCS);
|
||
gcov_write_unsigned (BB_TO_GCOV_INDEX (bb));
|
||
|
||
FOR_EACH_EDGE (e, ei, bb->succs)
|
||
{
|
||
struct edge_info *i = EDGE_INFO (e);
|
||
if (!i->ignore)
|
||
{
|
||
unsigned flag_bits = 0;
|
||
|
||
if (i->on_tree)
|
||
flag_bits |= GCOV_ARC_ON_TREE;
|
||
if (e->flags & EDGE_FAKE)
|
||
flag_bits |= GCOV_ARC_FAKE;
|
||
if (e->flags & EDGE_FALLTHRU)
|
||
flag_bits |= GCOV_ARC_FALLTHROUGH;
|
||
/* On trees we don't have fallthru flags, but we can
|
||
recompute them from CFG shape. */
|
||
if (e->flags & (EDGE_TRUE_VALUE | EDGE_FALSE_VALUE)
|
||
&& e->src->next_bb == e->dest)
|
||
flag_bits |= GCOV_ARC_FALLTHROUGH;
|
||
|
||
gcov_write_unsigned (BB_TO_GCOV_INDEX (e->dest));
|
||
gcov_write_unsigned (flag_bits);
|
||
}
|
||
}
|
||
|
||
gcov_write_length (offset);
|
||
}
|
||
}
|
||
|
||
/* Line numbers. */
|
||
if (coverage_begin_output ())
|
||
{
|
||
gcov_position_t offset;
|
||
|
||
/* Initialize the output. */
|
||
output_location (NULL, 0, NULL, NULL);
|
||
|
||
FOR_EACH_BB (bb)
|
||
{
|
||
block_stmt_iterator bsi;
|
||
|
||
offset = 0;
|
||
|
||
if (bb == ENTRY_BLOCK_PTR->next_bb)
|
||
{
|
||
expanded_location curr_location =
|
||
expand_location (DECL_SOURCE_LOCATION (current_function_decl));
|
||
output_location (curr_location.file, curr_location.line,
|
||
&offset, bb);
|
||
}
|
||
|
||
for (bsi = bsi_start (bb); !bsi_end_p (bsi); bsi_next (&bsi))
|
||
{
|
||
tree stmt = bsi_stmt (bsi);
|
||
if (EXPR_HAS_LOCATION (stmt))
|
||
output_location (EXPR_FILENAME (stmt), EXPR_LINENO (stmt),
|
||
&offset, bb);
|
||
}
|
||
|
||
/* Notice GOTO expressions we eliminated while constructing the
|
||
CFG. */
|
||
if (single_succ_p (bb) && single_succ_edge (bb)->goto_locus)
|
||
{
|
||
/* ??? source_locus type is marked deprecated in input.h. */
|
||
source_locus curr_location = single_succ_edge (bb)->goto_locus;
|
||
/* ??? The FILE/LINE API is inconsistent for these cases. */
|
||
#ifdef USE_MAPPED_LOCATION
|
||
output_location (LOCATION_FILE (curr_location),
|
||
LOCATION_LINE (curr_location), &offset, bb);
|
||
#else
|
||
output_location (curr_location->file, curr_location->line,
|
||
&offset, bb);
|
||
#endif
|
||
}
|
||
|
||
if (offset)
|
||
{
|
||
/* A file of NULL indicates the end of run. */
|
||
gcov_write_unsigned (0);
|
||
gcov_write_string (NULL);
|
||
gcov_write_length (offset);
|
||
}
|
||
}
|
||
}
|
||
|
||
ENTRY_BLOCK_PTR->index = ENTRY_BLOCK;
|
||
EXIT_BLOCK_PTR->index = EXIT_BLOCK;
|
||
#undef BB_TO_GCOV_INDEX
|
||
|
||
if (flag_profile_values)
|
||
find_values_to_profile (&values);
|
||
|
||
if (flag_branch_probabilities)
|
||
{
|
||
compute_branch_probabilities ();
|
||
if (flag_profile_values)
|
||
compute_value_histograms (values);
|
||
}
|
||
|
||
remove_fake_edges ();
|
||
|
||
/* For each edge not on the spanning tree, add counting code. */
|
||
if (profile_arc_flag
|
||
&& coverage_counter_alloc (GCOV_COUNTER_ARCS, num_instrumented))
|
||
{
|
||
unsigned n_instrumented;
|
||
|
||
profile_hooks->init_edge_profiler ();
|
||
|
||
n_instrumented = instrument_edges (el);
|
||
|
||
gcc_assert (n_instrumented == num_instrumented);
|
||
|
||
if (flag_profile_values)
|
||
instrument_values (values);
|
||
|
||
/* Commit changes done by instrumentation. */
|
||
bsi_commit_edge_inserts ();
|
||
}
|
||
|
||
free_aux_for_edges ();
|
||
|
||
VEC_free (histogram_value, heap, values);
|
||
free_edge_list (el);
|
||
if (flag_branch_probabilities)
|
||
profile_status = PROFILE_READ;
|
||
coverage_end_function ();
|
||
}
|
||
|
||
/* Union find algorithm implementation for the basic blocks using
|
||
aux fields. */
|
||
|
||
static basic_block
|
||
find_group (basic_block bb)
|
||
{
|
||
basic_block group = bb, bb1;
|
||
|
||
while ((basic_block) group->aux != group)
|
||
group = (basic_block) group->aux;
|
||
|
||
/* Compress path. */
|
||
while ((basic_block) bb->aux != group)
|
||
{
|
||
bb1 = (basic_block) bb->aux;
|
||
bb->aux = (void *) group;
|
||
bb = bb1;
|
||
}
|
||
return group;
|
||
}
|
||
|
||
static void
|
||
union_groups (basic_block bb1, basic_block bb2)
|
||
{
|
||
basic_block bb1g = find_group (bb1);
|
||
basic_block bb2g = find_group (bb2);
|
||
|
||
/* ??? I don't have a place for the rank field. OK. Lets go w/o it,
|
||
this code is unlikely going to be performance problem anyway. */
|
||
gcc_assert (bb1g != bb2g);
|
||
|
||
bb1g->aux = bb2g;
|
||
}
|
||
|
||
/* This function searches all of the edges in the program flow graph, and puts
|
||
as many bad edges as possible onto the spanning tree. Bad edges include
|
||
abnormals edges, which can't be instrumented at the moment. Since it is
|
||
possible for fake edges to form a cycle, we will have to develop some
|
||
better way in the future. Also put critical edges to the tree, since they
|
||
are more expensive to instrument. */
|
||
|
||
static void
|
||
find_spanning_tree (struct edge_list *el)
|
||
{
|
||
int i;
|
||
int num_edges = NUM_EDGES (el);
|
||
basic_block bb;
|
||
|
||
/* We use aux field for standard union-find algorithm. */
|
||
FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
|
||
bb->aux = bb;
|
||
|
||
/* Add fake edge exit to entry we can't instrument. */
|
||
union_groups (EXIT_BLOCK_PTR, ENTRY_BLOCK_PTR);
|
||
|
||
/* First add all abnormal edges to the tree unless they form a cycle. Also
|
||
add all edges to EXIT_BLOCK_PTR to avoid inserting profiling code behind
|
||
setting return value from function. */
|
||
for (i = 0; i < num_edges; i++)
|
||
{
|
||
edge e = INDEX_EDGE (el, i);
|
||
if (((e->flags & (EDGE_ABNORMAL | EDGE_ABNORMAL_CALL | EDGE_FAKE))
|
||
|| e->dest == EXIT_BLOCK_PTR)
|
||
&& !EDGE_INFO (e)->ignore
|
||
&& (find_group (e->src) != find_group (e->dest)))
|
||
{
|
||
if (dump_file)
|
||
fprintf (dump_file, "Abnormal edge %d to %d put to tree\n",
|
||
e->src->index, e->dest->index);
|
||
EDGE_INFO (e)->on_tree = 1;
|
||
union_groups (e->src, e->dest);
|
||
}
|
||
}
|
||
|
||
/* Now insert all critical edges to the tree unless they form a cycle. */
|
||
for (i = 0; i < num_edges; i++)
|
||
{
|
||
edge e = INDEX_EDGE (el, i);
|
||
if (EDGE_CRITICAL_P (e) && !EDGE_INFO (e)->ignore
|
||
&& find_group (e->src) != find_group (e->dest))
|
||
{
|
||
if (dump_file)
|
||
fprintf (dump_file, "Critical edge %d to %d put to tree\n",
|
||
e->src->index, e->dest->index);
|
||
EDGE_INFO (e)->on_tree = 1;
|
||
union_groups (e->src, e->dest);
|
||
}
|
||
}
|
||
|
||
/* And now the rest. */
|
||
for (i = 0; i < num_edges; i++)
|
||
{
|
||
edge e = INDEX_EDGE (el, i);
|
||
if (!EDGE_INFO (e)->ignore
|
||
&& find_group (e->src) != find_group (e->dest))
|
||
{
|
||
if (dump_file)
|
||
fprintf (dump_file, "Normal edge %d to %d put to tree\n",
|
||
e->src->index, e->dest->index);
|
||
EDGE_INFO (e)->on_tree = 1;
|
||
union_groups (e->src, e->dest);
|
||
}
|
||
}
|
||
|
||
FOR_BB_BETWEEN (bb, ENTRY_BLOCK_PTR, NULL, next_bb)
|
||
bb->aux = NULL;
|
||
}
|
||
|
||
/* Perform file-level initialization for branch-prob processing. */
|
||
|
||
void
|
||
init_branch_prob (void)
|
||
{
|
||
int i;
|
||
|
||
total_num_blocks = 0;
|
||
total_num_edges = 0;
|
||
total_num_edges_ignored = 0;
|
||
total_num_edges_instrumented = 0;
|
||
total_num_blocks_created = 0;
|
||
total_num_passes = 0;
|
||
total_num_times_called = 0;
|
||
total_num_branches = 0;
|
||
total_num_never_executed = 0;
|
||
for (i = 0; i < 20; i++)
|
||
total_hist_br_prob[i] = 0;
|
||
}
|
||
|
||
/* Performs file-level cleanup after branch-prob processing
|
||
is completed. */
|
||
|
||
void
|
||
end_branch_prob (void)
|
||
{
|
||
if (dump_file)
|
||
{
|
||
fprintf (dump_file, "\n");
|
||
fprintf (dump_file, "Total number of blocks: %d\n",
|
||
total_num_blocks);
|
||
fprintf (dump_file, "Total number of edges: %d\n", total_num_edges);
|
||
fprintf (dump_file, "Total number of ignored edges: %d\n",
|
||
total_num_edges_ignored);
|
||
fprintf (dump_file, "Total number of instrumented edges: %d\n",
|
||
total_num_edges_instrumented);
|
||
fprintf (dump_file, "Total number of blocks created: %d\n",
|
||
total_num_blocks_created);
|
||
fprintf (dump_file, "Total number of graph solution passes: %d\n",
|
||
total_num_passes);
|
||
if (total_num_times_called != 0)
|
||
fprintf (dump_file, "Average number of graph solution passes: %d\n",
|
||
(total_num_passes + (total_num_times_called >> 1))
|
||
/ total_num_times_called);
|
||
fprintf (dump_file, "Total number of branches: %d\n",
|
||
total_num_branches);
|
||
fprintf (dump_file, "Total number of branches never executed: %d\n",
|
||
total_num_never_executed);
|
||
if (total_num_branches)
|
||
{
|
||
int i;
|
||
|
||
for (i = 0; i < 10; i++)
|
||
fprintf (dump_file, "%d%% branches in range %d-%d%%\n",
|
||
(total_hist_br_prob[i] + total_hist_br_prob[19-i]) * 100
|
||
/ total_num_branches, 5*i, 5*i+5);
|
||
}
|
||
}
|
||
}
|
||
|
||
/* Set up hooks to enable tree-based profiling. */
|
||
|
||
void
|
||
tree_register_profile_hooks (void)
|
||
{
|
||
gcc_assert (ir_type ());
|
||
profile_hooks = &tree_profile_hooks;
|
||
}
|
||
|