From 728c5e87c655c17c2fbc1d5386b12ff328e0fc76 Mon Sep 17 00:00:00 2001
From: David Gibson <david@gibson.dropbear.id.au>
Date: Tue, 8 Dec 2009 14:24:42 +1100
Subject: [PATCH] dtc: Cleanup line number tracking, add column number tracking

Our YYLTYPE current carries around first and last line and first and
last column information.  However, of these, on the first line
information is actually filled in properly.

Furthermore, filling in the line number information from yylineno is
kind of clunky: we have to copy its value to the srcfile stack and
back to handle include file positioning correctly.

This patch cleans this up.  We turn off flex's yylineno option and
instead track the line and column number ourselves from
YY_USER_ACTION.  The line and column number are stored directly inside
the srcfile_state structure, so it's automatically a per-file
quantity.  We now also fill in all the yylloc from YY_USER_ACTION.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 dtc-lexer.l | 11 ++++-------
 srcpos.c    | 33 ++++++++++++++++++++++++++++++++-
 srcpos.h    |  3 ++-
 3 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/dtc-lexer.l b/dtc-lexer.l
index 12467c0..9021231 100644
--- a/dtc-lexer.l
+++ b/dtc-lexer.l
@@ -18,7 +18,7 @@
  *                                                                   USA
  */
 
-%option noyywrap nounput noinput yylineno
+%option noyywrap nounput noinput
 
 %x INCLUDE
 %x BYTESTRING
@@ -38,10 +38,11 @@ LINECOMMENT	"//".*\n
 #include "srcpos.h"
 #include "dtc-parser.tab.h"
 
+
+/* CAUTION: this will stop working if we ever use yyless() or yyunput() */
 #define	YY_USER_ACTION \
 	{ \
-		yylloc.file = current_srcfile; \
-		yylloc.first_line = yylineno; \
+		srcpos_update(&yylloc, yytext, yyleng); \
 	}
 
 /*#define LEXDEBUG	1*/
@@ -169,12 +170,9 @@ static void push_input_file(const char *filename)
 {
 	assert(filename);
 
-	current_srcfile->lineno = yylineno;
-
 	srcfile_push(filename);
 
 	yyin = current_srcfile->f;
-	yylineno = 1;
 
 	yypush_buffer_state(yy_create_buffer(yyin, YY_BUF_SIZE));
 }
@@ -186,7 +184,6 @@ static int pop_input_file(void)
 		return 0;
 
 	yypop_buffer_state();
-	yylineno = current_srcfile->lineno;
 	yyin = current_srcfile->f;
 
 	return 1;
diff --git a/srcpos.c b/srcpos.c
index f08c1c3..ca322bb 100644
--- a/srcpos.c
+++ b/srcpos.c
@@ -87,6 +87,10 @@ void srcfile_push(const char *fname)
 	srcfile->f = srcfile_relative_open(fname, &srcfile->name);
 	srcfile->dir = dirname(srcfile->name);
 	srcfile->prev = current_srcfile;
+
+	srcfile->lineno = 1;
+	srcfile->colno = 1;
+
 	current_srcfile = srcfile;
 }
 
@@ -99,7 +103,8 @@ int srcfile_pop(void)
 	current_srcfile = srcfile->prev;
 
 	if (fclose(srcfile->f))
-		die("Error closing \"%s\": %s\n", srcfile->name, strerror(errno));
+		die("Error closing \"%s\": %s\n", srcfile->name,
+		    strerror(errno));
 
 	/* FIXME: We allow the srcfile_state structure to leak,
 	 * because it could still be referenced from a location
@@ -122,6 +127,32 @@ srcpos srcpos_empty = {
 	.file = NULL,
 };
 
+#define TAB_SIZE      8
+
+void srcpos_update(srcpos *pos, const char *text, int len)
+{
+	int i;
+
+	pos->file = current_srcfile;
+
+	pos->first_line = current_srcfile->lineno;
+	pos->first_column = current_srcfile->colno;
+
+	for (i = 0; i < len; i++)
+		if (text[i] == '\n') {
+			current_srcfile->lineno++;
+			current_srcfile->colno = 1;
+		} else if (text[i] == '\t') {
+			current_srcfile->colno =
+				ALIGN(current_srcfile->colno, TAB_SIZE);
+		} else {
+			current_srcfile->colno++;
+		}
+
+	pos->last_line = current_srcfile->lineno;
+	pos->last_column = current_srcfile->colno;
+}
+
 srcpos *
 srcpos_copy(srcpos *pos)
 {
diff --git a/srcpos.h b/srcpos.h
index 38cc988..eb60244 100644
--- a/srcpos.h
+++ b/srcpos.h
@@ -31,7 +31,7 @@ struct srcfile_state {
 	FILE *f;
 	char *name;
 	char *dir;
-	int lineno;
+	int lineno, colno;
 	struct srcfile_state *prev;
 };
 
@@ -89,6 +89,7 @@ typedef YYLTYPE srcpos;
  */
 extern srcpos srcpos_empty;
 
+extern void srcpos_update(srcpos *pos, const char *text, int len);
 extern srcpos *srcpos_copy(srcpos *pos);
 extern char *srcpos_string(srcpos *pos);
 extern void srcpos_dump(srcpos *pos);