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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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9
src/symtab.c
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@@ -105,6 +105,7 @@ symbol_new (uniqstr tag, location loc)
res->tag = tag;
res->location = loc;
res->location_of_lhs = false;
res->alias = NULL;
res->content = sym_content_new (res);
res->is_alias = false;
@@ -189,6 +190,7 @@ code_props_type_string (code_props_type kind)
assert (0);
}
/*----------------------------------------.
| Create a new semantic type, named TAG. |
`----------------------------------------*/
@@ -307,6 +309,13 @@ semantic_type_redeclaration (semantic_type *s, const char *what, location first,
}
void
symbol_location_as_lhs_set (symbol *sym, location loc)
{
if (!sym->location_of_lhs)
sym->location = loc;
}
/*-----------------------------------------------------------------.
| Set the TYPE_NAME associated with SYM. Does nothing if passed 0 |