From 6900ae9eeee397436df25ef51835a8b27865d46d Mon Sep 17 00:00:00 2001
From: Masahiro Yamada <yamada.masahiro@socionext.com>
Date: Tue, 11 Dec 2018 20:00:52 +0900
Subject: [PATCH] kconfig: remove grammatically ambiguous "unexpected option"
diagnostic
This commit decreases 15 shift/reduce conflicts.
The location of this error recovery is ambiguous.
For example, there are two ways to interpret the following code:
1 config FOO
2 bool "foo"
[A] Both lines are reduced together into a config_stmt.
[B] The only line 1 is reduced into a config_stmt, and the line 2
matches to "option_name error T_EOL"
Of course, we expect [A], but [B] could be grammatically possible.
Kconfig has no terminator for a config block. So, we cannot detect its
end until we see a non-property keyword. People often insert a blank
line between two config blocks, but it is just a coding convention.
Blank lines are actually allowed anywhere in Kconfig files.
The real error is when a property keyword appears right after "endif",
"endchoice", "endmenu", "source", "comment", or variable assignment.
Instead of fixing the grammatical ambiguity, I chose to simply remove
this error recovery.
The difference is
unexpected option "bool"
... is turned into a more generic message:
invalid statement
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---
scripts/kconfig/zconf.y | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/scripts/kconfig/zconf.y b/scripts/kconfig/zconf.y
index 02bfc62ba92c0..cef6123228c01 100644
--- a/scripts/kconfig/zconf.y
+++ b/scripts/kconfig/zconf.y
@@ -31,7 +31,7 @@ struct symbol *symbol_hash[SYMBOL_HASHSIZE];
static struct menu *current_menu, *current_entry;
%}
-%expect 21
+%expect 6
%union
{
@@ -94,7 +94,6 @@ static struct menu *current_menu, *current_entry;
%type <expr> expr
%type <expr> if_expr
%type <id> end
-%type <id> option_name
%type <menu> if_entry menu_entry choice_entry
%type <string> symbol_option_arg word_opt assign_val
@@ -127,17 +126,9 @@ stmt_list:
| stmt_list menu_stmt
| stmt_list end { zconf_error("unexpected end statement"); }
| stmt_list T_WORD error T_EOL { zconf_error("unknown statement \"%s\"", $2); }
- | stmt_list option_name error T_EOL
-{
- zconf_error("unexpected option \"%s\"", $2->name);
-}
| stmt_list error T_EOL { zconf_error("invalid statement"); }
;
-option_name:
- T_DEPENDS | T_PROMPT | T_TYPE | T_SELECT | T_IMPLY | T_OPTIONAL | T_RANGE | T_DEFAULT | T_VISIBLE
-;
-
common_stmt:
if_stmt
| comment_stmt
--
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