Bring back dot_flow.c.

However, it produces simplified flow graphs (ie, just nodes and edges, no
statements, though later on data flow information will be added).

tools/qfcc/include/flow.h

@@ -50,6 +50,11 @@ typedef struct flowedge_s {
 	unsigned    head;		//< successor index
 } flowedge_t;
 
+/** Represent a node in a flow graph.
+
+	With the \a siblings and \a num_siblings fields, the entire graph can be
+	accessed via any node within that graph.
+*/
 typedef struct flownode_s {
 	struct flownode_s *next;
 	unsigned    id;
@@ -77,6 +82,7 @@ typedef struct flownode_s {
 	struct sblock_s **sblocks;
 	struct flownode_s **nodes;
 	struct flownode_s **siblings;
+	unsigned    num_siblings;
 	//@}
 	struct set_s *dom;
 } flownode_t;
@@ -87,6 +93,7 @@ int flow_is_return (struct statement_s *s);
 struct sblock_s *flow_get_target (struct statement_s *s);
 void flow_build_vars (struct function_s *func);
 void flow_build_graph (struct function_s *func);
+void print_flowgraph (flownode_t *flow, const char *filename);
 
 //@}
 

tools/qfcc/include/function.h

@@ -95,6 +95,7 @@ typedef struct function_s {
 	struct daglabel_s **vars;
 	int                 num_vars;	///< total number of variables referenced
 	struct flowloop_s *loops;		///< linked list of loops in the function
+	struct flownode_s *flow;		///< flow graph
 } function_t;
 
 extern function_t *current_func;

tools/qfcc/source/Makefile.am

@@ -40,7 +40,7 @@ bin_SCRIPTS=	qfpreqcc
 
 common_src=\
 	class.c codespace.c constfold.c cpp.c dags.c debug.c def.c defspace.c \
-	diagnostic.c dot_dag.c dot_expr.c dot_sblock.c emit.c expr.c \
+	diagnostic.c dot_dag.c dot_expr.c dot_flow.c dot_sblock.c emit.c expr.c \
 	flow.c function.c grab.c idstuff.c linker.c method.c obj_file.c \
 	obj_type.c opcodes.c options.c qfcc.c reloc.c set.c shared.c statements.c \
 	strpool.c struct.c switch.c symtab.c type.c value.c

tools/qfcc/source/dot_flow.c

@@ -0,0 +1,86 @@
+/*
+	dot_flow.c
+
+	"emit" flow graphs to dot (graphvis).
+
+	Copyright (C) 2012 Bill Currie <bill@taniwha.org>
+
+	Author: Bill Currie <bill@taniwha.org>
+	Date: 2012/11/01
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+	See the GNU General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with this program; if not, write to:
+
+		Free Software Foundation, Inc.
+		59 Temple Place - Suite 330
+		Boston, MA  02111-1307, USA
+
+*/
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#ifdef HAVE_STRING_H
+# include <string.h>
+#endif
+#ifdef HAVE_STRINGS_H
+# include <strings.h>
+#endif
+#include <stdlib.h>
+
+#include <QF/dstring.h>
+#include <QF/quakeio.h>
+#include <QF/va.h>
+
+#include "dags.h"
+#include "flow.h"
+#include "expr.h"
+#include "strpool.h"
+
+static void
+print_flownode (dstring_t *dstr, flownode_t *node, int level)
+{
+	int         indent = level * 2 + 2;
+	int         i;
+
+	dasprintf (dstr, "%*s\"fn_%p\" [label=\"%d\"];\n", indent, "", node,
+			   node->id);
+	for (i = 0; i < node->num_succ; i++)
+		dasprintf (dstr, "%*s\"fn_%p\" -> \"fn_%p\";\n", indent, "", node,
+				   node->siblings[node->successors[i]]);
+}
+
+void
+print_flowgraph (flownode_t *flow, const char *filename)
+{
+	unsigned    i;
+	dstring_t  *dstr = dstring_newstr();
+
+	dasprintf (dstr, "digraph flow_%p {\n", flow->siblings);
+	dasprintf (dstr, "  layout=dot; rankdir=TB;\n");
+	for (i = 0; i < flow->num_siblings; i++)
+		print_flownode (dstr, flow->siblings[i], 0);
+	dasprintf (dstr, "}\n");
+
+	if (filename) {
+		QFile      *file;
+
+		file = Qopen (filename, "wt");
+		Qwrite (file, dstr->str, dstr->size - 1);
+		Qclose (file);
+	} else {
+		fputs (dstr->str, stdout);
+	}
+	dstring_delete (dstr);
+}

tools/qfcc/source/flow.c

@@ -380,6 +380,7 @@ flow_build_graph (function_t *func)
 		node = new_node ();
 		node->sblocks = func->graph;
 		node->siblings = node_list;
+		node->num_siblings = num_blocks;
 		node->id = sblock->number;
 		node->num_nodes = func->num_nodes;
 
@@ -422,4 +423,5 @@ flow_build_graph (function_t *func)
 	flow_find_predecessors (node_list, num_blocks);
 	flow_calc_dominators (node_list, num_blocks);
 	func->loops = flow_find_loops (node_list, num_blocks);
+	func->flow = node_list[0];
 }

tools/qfcc/source/function.c

@@ -646,8 +646,8 @@ emit_function (function_t *f, expr_t *e)
 	flow_build_vars (f);
 	flow_build_graph (f);
 	if (options.block_dot.flow)
-		print_sblock (f->sblock, nva ("%s.%s.%s.dot", GETSTR (pr.source_file),
-									  f->name, "flow"));
+		print_flowgraph (f->flow, nva ("%s.%s.%s.dot", GETSTR (pr.source_file),
+									   f->name, "flow"));
 	{
 		flowloop_t *l;
 		int         n = 0;