Conditionalization of the debug flag moves to m4.

Turned out to be mildly trick because %if/%endif pairs have push/pop
behavior rather than combining.

In generated code, the location of the debug declarations moves,
and that's all.

#34 in the retargeting patch series

4 files changed, 21 insertions, 8 deletions

diff --git a/src/cpp-flex.skl b/src/cpp-flex.skl
index 707e013..b3838b1 100644
--- a/src/cpp-flex.skl
+++ b/src/cpp-flex.skl
@@ -724,6 +724,14 @@ m4_ifdef([[M4_MODE_YYTEXT_IS_ARRAY]], [[ \
 ]]) \
 	YY_G(yy_c_buf_p) = yy_cp;
 
+%if-not-reentrant
+m4_ifdef( [[M4_MODE_C_ONLY]],
+[[
+extern int yy_flex_debug;
+int yy_flex_debug = m4_ifdef([[M4_MODE_DEBUG]],[[1]])m4_ifdef([[M4_MODE_NO_DEBUG]],[[1]]);
+]])
+%endif
+
 %% [2.0] code to fiddle yytext and yyleng for yymore() goes here \
 %% [3.0] code to copy yytext_ptr to yytext[] goes here, if %array \
 %% [4.0] data tables for the DFA and the user's section 1 definitions go here
diff --git a/src/flexdef.h b/src/flexdef.h
index f8575a6..15250b6 100644
--- a/src/flexdef.h
+++ b/src/flexdef.h
@@ -350,6 +350,8 @@ struct flex_backend_t {
 
 extern bool gentables;
 
+extern struct flex_backend_t cpp_backend;
+
 /* Declarations for global variables. */
 
 
diff --git a/src/gen.c b/src/gen.c
index e5a8db4..e3de32e 100644
--- a/src/gen.c
+++ b/src/gen.c
@@ -992,11 +992,22 @@ void make_tables (void)
 
 	if (ddebug)
 		out_m4_define( "M4_MODE_DEBUG", NULL);
+	else
+		out_m4_define( "M4_MODE_NO_DEBUG", NULL);
+
+	// Kluge to get around the fact that the %if-not-reentrant and
+	// %if-c-only gates can;t be combined by nesting one inside the
+	// other.
+	if (backend == &cpp_backend && !C_plus_plus)
+		out_m4_define( "M4_MODE_C_ONLY", NULL);
 
 	// FIXME: This probaby should be done in pure m4 
 	out_m4_define("M4_YYL_BASE", yymore_used ? (yytext_is_array ? "YY_G(yy_prev_more_offset)" :
 						    "YY_G(yy_more_len)") : "0");
 	
+	// There are a couple more modes we can't compute until after
+	// tables have been generated.
+
 	out_dec ("#define YY_NUM_RULES %d\n", num_rules);
 	out_dec ("#define YY_END_OF_BUFFER %d\n", num_rules + 1);
 
@@ -1173,12 +1184,6 @@ void make_tables (void)
 		}
 	}
 
-	if (!C_plus_plus && !reentrant) {
-		indent_puts ("extern int yy_flex_debug;");
-		indent_put2s ("int yy_flex_debug = %s;\n",
-			      ddebug ? "1" : "0");
-	}
-
 	if (reject) {
 		outn ("m4_ifdef( [[M4_MODE_USES_REJECT]],\n[[");
 		/* Declare state buffer variables. */
diff --git a/src/main.c b/src/main.c
index 5fa53da..2ba677b 100644
--- a/src/main.c
+++ b/src/main.c
@@ -46,8 +46,6 @@ void flexinit(int, char **);
 void readin(void);
 void set_up_initial_allocations(void);
 
-extern struct flex_backend_t cpp_backend;
-
 /* these globals are all defined and commented in flexdef.h */
 int     printstats, syntaxerror, eofseen, ddebug, trace, nowarn, spprdflt;
 int     interactive, lex_compat, posix_compat, do_yylineno,