Have separate flags for "optimizer debug" and "print DOT graph".

Instead of having -dddd mean "-ddd and print the CFG as a DOT graph",
have a separate -g flag to request the CFG.

Also, put the routines to set the "optimizer debug" and "print DOT
graph" flags into optimize.c, and make the flags in question static.

(And "CFG graph" is redundant, like "ATM machine", "PIN number", and "NT
technology"....)

optimize.c

@@ -44,7 +44,56 @@
 #endif
 
 #ifdef BDEBUG
-int pcap_optimizer_debug;
+/*
+ * The internal "debug printout" flag for the filter expression optimizer.
+ * The code to print that stuff is present only if BDEBUG is defined, so
+ * the flag, and the routine to set it, are defined only if BDEBUG is
+ * defined.
+ */
+static int pcap_optimizer_debug;
+
+/*
+ * Routine to set that flag.
+ *
+ * This is intended for libpcap developers, not for general use.
+ * If you want to set these in a program, you'll have to declare this
+ * routine yourself, with the appropriate DLL import attribute on Windows;
+ * it's not declared in any header file, and won't be declared in any
+ * header file provided by libpcap.
+ */
+PCAP_API void pcap_set_optimizer_debug(int value);
+
+PCAP_API_DEF void
+pcap_set_optimizer_debug(int value)
+{
+	pcap_optimizer_debug = value;
+}
+
+/*
+ * The internal "print dot graph" flag for the filter expression optimizer.
+ * The code to print that stuff is present only if BDEBUG is defined, so
+ * the flag, and the routine to set it, are defined only if BDEBUG is
+ * defined.
+ */
+static int pcap_print_dot_graph;
+
+/*
+ * Routine to set that flag.
+ *
+ * This is intended for libpcap developers, not for general use.
+ * If you want to set these in a program, you'll have to declare this
+ * routine yourself, with the appropriate DLL import attribute on Windows;
+ * it's not declared in any header file, and won't be declared in any
+ * header file provided by libpcap.
+ */
+PCAP_API void pcap_set_print_dot_graph(int value);
+
+PCAP_API_DEF void
+pcap_set_print_dot_graph(int value)
+{
+	pcap_print_dot_graph = value;
+}
+
 #endif
 
 /*
@@ -1733,7 +1782,7 @@ opt_loop(compiler_state_t *cstate, opt_state_t *opt_state, struct icode *ic,
 {
 
 #ifdef BDEBUG
-	if (pcap_optimizer_debug > 1) {
+	if (pcap_optimizer_debug > 1 || pcap_print_dot_graph) {
 		printf("opt_loop(root, %d) begin\n", do_stmts);
 		opt_dump(cstate, ic);
 	}
@@ -1747,7 +1796,7 @@ opt_loop(compiler_state_t *cstate, opt_state_t *opt_state, struct icode *ic,
 		find_edom(opt_state, ic->root);
 		opt_blks(cstate, opt_state, ic, do_stmts);
 #ifdef BDEBUG
-		if (pcap_optimizer_debug > 1) {
+		if (pcap_optimizer_debug > 1 || pcap_print_dot_graph) {
 			printf("opt_loop(root, %d) bottom, done=%d\n", do_stmts, opt_state->done);
 			opt_dump(cstate, ic);
 		}
@@ -1768,14 +1817,14 @@ bpf_optimize(compiler_state_t *cstate, struct icode *ic)
 	opt_loop(cstate, &opt_state, ic, 1);
 	intern_blocks(&opt_state, ic);
 #ifdef BDEBUG
-	if (pcap_optimizer_debug > 1) {
+	if (pcap_optimizer_debug > 1 || pcap_print_dot_graph) {
 		printf("after intern_blocks()\n");
 		opt_dump(cstate, ic);
 	}
 #endif
 	opt_root(&ic->root);
 #ifdef BDEBUG
-	if (pcap_optimizer_debug > 1) {
+	if (pcap_optimizer_debug > 1 || pcap_print_dot_graph) {
 		printf("after opt_root()\n");
 		opt_dump(cstate, ic);
 	}
@@ -2437,11 +2486,11 @@ plain_dump(compiler_state_t *cstate, struct icode *ic)
 static void
 opt_dump(compiler_state_t *cstate, struct icode *ic)
 {
-	/* if optimizer debugging is enabled, output DOT graph
-	 * `pcap_optimizer_debug=4' is equivalent to -dddd to follow -d/-dd/-ddd
-	 * convention in tcpdump command line
+	/*
+	 * If the CFG, in DOT format, is requested, output it rather than
+	 * the code that would be generated from that graph.
 	 */
-	if (pcap_optimizer_debug > 3)
+	if (pcap_print_dot_graph)
 		dot_dump(cstate, ic);
 	else
 		plain_dump(cstate, ic);

optimize.h

@@ -23,8 +23,6 @@
  * Some stuff for use when debugging the optimizer.
  */
 #ifdef BDEBUG
-extern int pcap_optimizer_debug;	/* optimizer debugging level */
-
 #define NBIDS	1000
 extern int bids[NBIDS];
 #endif

pcap.c

@@ -3944,25 +3944,3 @@ pcap_set_parser_debug(int value)
 	pcap_debug = value;
 }
 #endif
-
-#ifdef BDEBUG
-/*
- * Set the internal "debug printout" flag for the filter expression optimizer.
- * The code to print that stuff is present only if BDEBUG is defined, so
- * the flag, and the routine to set it, are defined only if BDEBUG is
- * defined.
- *
- * This is intended for libpcap developers, not for general use.
- * If you want to set these in a program, you'll have to declare this
- * routine yourself, with the appropriate DLL import attribute on Windows;
- * it's not declared in any header file, and won't be declared in any
- * header file provided by libpcap.
- */
-PCAP_API void pcap_set_optimizer_debug(int value);
-
-PCAP_API_DEF void
-pcap_set_optimizer_debug(int value)
-{
-	pcap_optimizer_debug = value;
-}
-#endif

testprogs/filtertest.c

@@ -58,12 +58,14 @@ The Regents of the University of California.  All rights reserved.\n";
 
 #ifdef BDEBUG
 /*
- * We have pcap_set_optimizer_debug() in libpcap; declare it (it's not declared
- * by any libpcap header, because it's a special hack, only available if
- * libpcap was configured to include it, and only intended for use by
- * libpcap developers trying to debug the optimizer for filter expressions).
+ * We have pcap_set_optimizer_debug() and pcap_set_print_dot_graph() in
+ * libpcap; declare them (they're not declared by any libpcap header,
+ * because they're special hacks, only available if libpcap was configured
+ * to include them, and only intended for use by libpcap developers trying
+ * to debug the optimizer for filter expressions).
  */
 PCAP_API void pcap_set_optimizer_debug(int);
+PCAP_API void pcap_set_print_dot_graph(int);
 #endif
 
 static char *program_name;
@@ -194,6 +196,7 @@ main(int argc, char **argv)
 	char *cp;
 	int op;
 	int dflag;
+	int gflag;
 	char *infile;
 	int Oflag;
 	long snaplen;
@@ -210,15 +213,9 @@ main(int argc, char **argv)
 		return 1;
 #endif /* _WIN32 */
 
-#ifndef BDEBUG
 	dflag = 1;
-#else
-	/* if optimizer debugging is enabled, output DOT graph
-	 * `dflag=4' is equivalent to -dddd to follow -d/-dd/-ddd
-	 * convention in tcpdump command line
-	 */
-	dflag = 4;
-#endif
+	gflag = 0;
+
 	infile = NULL;
 	Oflag = 1;
 	snaplen = 68;
@@ -229,13 +226,21 @@ main(int argc, char **argv)
 		program_name = argv[0];
 
 	opterr = 0;
-	while ((op = getopt(argc, argv, "dF:m:Os:")) != -1) {
+	while ((op = getopt(argc, argv, "dF:gm:Os:")) != -1) {
 		switch (op) {
 
 		case 'd':
 			++dflag;
 			break;
 
+		case 'g':
+#ifdef BDEBUG
+			++gflag;
+#else
+			error("libpcap and filtertest not built with optimizer debugging enabled");
+#endif
+			break;
+
 		case 'F':
 			infile = optarg;
 			break;
@@ -302,6 +307,7 @@ main(int argc, char **argv)
 
 #ifdef BDEBUG
 	pcap_set_optimizer_debug(dflag);
+	pcap_set_print_dot_graph(gflag);
 #endif
 
 	pd = pcap_open_dead(dlt, snaplen);
@@ -343,7 +349,11 @@ usage(void)
 	(void)fprintf(stderr, "%s, with %s\n", program_name,
 	    pcap_lib_version());
 	(void)fprintf(stderr,
+#ifdef BDEBUG
+	    "Usage: %s [-dgO] [ -F file ] [ -m netmask] [ -s snaplen ] dlt [ expression ]\n",
+#else
 	    "Usage: %s [-dO] [ -F file ] [ -m netmask] [ -s snaplen ] dlt [ expression ]\n",
+#endif
 	    program_name);
 	exit(1);
 }

testprogs/visopts.py

@@ -10,20 +10,21 @@
        ./configure --enable-optimizer-dbg
        make
        make testprogs
-2. Run filtertest to compile BPF expression, save to output a.txt
-       testprogs/filtertest EN10MB host 192.168.1.1 > a.txt
+2. Run filtertest to compile BPF expression and produce the CFG as a
+   DOT graph, save to output a.txt
+       testprogs/filtertest -g EN10MB host 192.168.1.1 > a.txt
 3. Send a.txt to this program's standard input
        cat a.txt | testprogs/visopts.py
 4. Step 2&3 can be merged:
-       testprogs/filtertest EN10MB host 192.168.1.1 | testprogs/visopts.py
+       testprogs/filtertest -g EN10MB host 192.168.1.1 | testprogs/visopts.py
 5. The standard output is something like this:
        generated files under directory: /tmp/visopts-W9ekBw
          the directory will be removed when this programs finished.
        open this link: http://localhost:39062/expr1.html
 6. Using open link at the 3rd line `http://localhost:39062/expr1.html'
 
 Note:
-1. CFG graph is translated to SVG document, expr1.html embeded them as external
+1. The CFG is translated to SVG an document, expr1.html embeded them as external
    document. If you open expr1.html as local file using file:// protocol, some
    browsers will deny such requests so the web pages will not shown properly.
    For chrome, you can run it using following command to avoid this: