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symbol: use the first occurrence as an LHS as defining location

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Currently on the following grammar:

    %type <foo> foo
    %%
    start: foo | bar | "baz"
    foo: foo
    bar: bar

bison reports:

    warning: 2 nonterminals useless in grammar [-Wother]
    warning: 4 rules useless in grammar [-Wother]
    1.13-15: warning: nonterminal useless in grammar: foo [-Wother]
     %type <foo> foo
                 ^^^
    3.14-16: warning: nonterminal useless in grammar: bar [-Wother]
     start: foo | bar | "baz"
                  ^^^
    [...]

i.e., the location of the first occurrence of a symbol is taken as its
definition point.  In the case of nonterminals, the first occurrence
as a left-hand side of a rule makes more sense:

    warning: 2 nonterminals useless in grammar [-Wother]
    warning: 4 rules useless in grammar [-Wother]
    4.1-3: warning: nonterminal useless in grammar: foo [-Wother]
     foo: foo
     ^^^
    5.1-3: warning: nonterminal useless in grammar: bar [-Wother]
     bar: bar
     ^^^
    [...]

* src/symtab.h, src/symtab.c (symbol::location_of_lhs): New.
(symbol_location_as_lhs_set): New.
* src/parse-gram.y (current_lhs): Use it.
* tests/reduce.at: Update locations.
This commit is contained in:
Akim Demaille
2015-01-14 13:41:32 +01:00
parent 650af77812
commit 875ef1b90c
7 changed files with 46 additions and 17 deletions
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6
src/parse-gram.c
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@@ -1,4 +1,4 @@
/* A Bison parser, made by GNU Bison 3.0.2.13-975bb-dirty. */
/* A Bison parser, made by GNU Bison 3.0.2.29-9a91e. */
/* Bison implementation for Yacc-like parsers in C
@@ -44,7 +44,7 @@
#define YYBISON 1
/* Bison version. */
#define YYBISON_VERSION "3.0.2.13-975bb-dirty"
#define YYBISON_VERSION "3.0.2.29-9a91e"
/* Skeleton name. */
#define YYSKELETON_NAME "yacc.c"
@@ -3118,6 +3118,8 @@ current_lhs (symbol *sym, location loc, named_ref *ref)
{
current_lhs_symbol = sym;
current_lhs_location = loc;
if (sym)
symbol_location_as_lhs_set (sym, loc);
/* In order to simplify memory management, named references for lhs
are always assigned by deep copy into the current symbol_list
node. This is because a single named-ref in the grammar may