[PATCH 3/3] kconfig: use yylineno option instead of manual lineno increments

From: Masahiro Yamada
Date: Thu Mar 22 2018 - 13:01:33 EST


Tracking the line number by hand is error-prone since we need to make
sure to increment it in all the \n matching patterns.

If '%option yylineno' is set, flex defines 'yylineno' to contain the
current line number and automatically updates it each time it reads a
\n character. This is much more convenient although the lexer does
not initializes yylineno, so you need to set it to 1 each time you
start reading a new file, and restore it you go back to the previous
file.

I tested this with DEBUG_PARSE, and confirmed the same dump message
was produced.

I removed the perf-report option. Otherwise, I see the following
message:
%option yylineno entails a performance penalty ONLY on rules that
can match newline characters

Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
---

scripts/kconfig/lkc.h | 1 +
scripts/kconfig/zconf.l | 20 +++++++++-----------
2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/scripts/kconfig/lkc.h b/scripts/kconfig/lkc.h
index 2d5ec2d..f4394af 100644
--- a/scripts/kconfig/lkc.h
+++ b/scripts/kconfig/lkc.h
@@ -68,6 +68,7 @@ struct kconf_id {
enum symbol_type stype;
};

+extern int yylineno;
void zconfdump(FILE *out);
void zconf_starthelp(void);
FILE *zconf_fopen(const char *name);
diff --git a/scripts/kconfig/zconf.l b/scripts/kconfig/zconf.l
index 29b5d33..045093d 100644
--- a/scripts/kconfig/zconf.l
+++ b/scripts/kconfig/zconf.l
@@ -1,5 +1,5 @@
%option nostdinit noyywrap never-interactive full ecs
-%option 8bit nodefault perf-report perf-report
+%option 8bit nodefault yylineno
%option noinput
%x COMMAND HELP STRING PARAM
%{
@@ -83,7 +83,6 @@ n [A-Za-z0-9_-]

[ \t]*#.*\n |
[ \t]*\n {
- current_file->lineno++;
return T_EOL;
}
[ \t]*#.*
@@ -104,7 +103,7 @@ n [A-Za-z0-9_-]
const struct kconf_id *id = kconf_id_lookup(yytext, yyleng);
BEGIN(PARAM);
current_pos.file = current_file;
- current_pos.lineno = current_file->lineno;
+ current_pos.lineno = yylineno;
if (id && id->flags & TF_COMMAND) {
yylval.id = id;
return id->token;
@@ -116,7 +115,6 @@ n [A-Za-z0-9_-]
. warn_ignored_character(*yytext);
\n {
BEGIN(INITIAL);
- current_file->lineno++;
return T_EOL;
}
}
@@ -138,7 +136,7 @@ n [A-Za-z0-9_-]
new_string();
BEGIN(STRING);
}
- \n BEGIN(INITIAL); current_file->lineno++; return T_EOL;
+ \n BEGIN(INITIAL); return T_EOL;
({n}|[/.])+ {
const struct kconf_id *id = kconf_id_lookup(yytext, yyleng);
if (id && id->flags & TF_PARAM) {
@@ -150,7 +148,7 @@ n [A-Za-z0-9_-]
return T_WORD;
}
#.* /* comment */
- \\\n current_file->lineno++;
+ \\\n ;
[[:blank:]]+
. warn_ignored_character(*yytext);
<<EOF>> {
@@ -187,7 +185,6 @@ n [A-Za-z0-9_-]
fprintf(stderr,
"%s:%d:warning: multi-line strings not supported\n",
zconf_curname(), zconf_lineno());
- current_file->lineno++;
BEGIN(INITIAL);
return T_EOL;
}
@@ -220,12 +217,10 @@ n [A-Za-z0-9_-]
}
}
[ \t]*\n/[^ \t\n] {
- current_file->lineno++;
zconf_endhelp();
return T_HELPTEXT;
}
[ \t]*\n {
- current_file->lineno++;
append_string("\n", 1);
}
[^ \t\n].* {
@@ -304,7 +299,7 @@ void zconf_initscan(const char *name)
memset(current_buf, 0, sizeof(*current_buf));

current_file = file_lookup(name);
- current_file->lineno = 1;
+ yylineno = 1;
}

void zconf_nextfile(const char *name)
@@ -325,6 +320,7 @@ void zconf_nextfile(const char *name)
buf->parent = current_buf;
current_buf = buf;

+ current_file->lineno = yylineno;
file->parent = current_file;

for (iter = current_file; iter; iter = iter->parent) {
@@ -343,7 +339,7 @@ void zconf_nextfile(const char *name)
}
}

- file->lineno = 1;
+ yylineno = 1;
current_file = file;
}

@@ -352,6 +348,8 @@ static void zconf_endfile(void)
struct buffer *parent;

current_file = current_file->parent;
+ if (current_file)
+ yylineno = current_file->lineno;

parent = current_buf->parent;
if (parent) {
--
2.7.4