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backend: revamp the handling of symbol types

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Currently it is the front end that passes the symbol types to the
backend.  For instance:

  %token <ival> NUM
  %type <ival> exp1 exp2
  exp1: NUM { $$ = $1; }
  exp2: NUM { $<ival>$ = $<ival>1; }

In both cases, $$ and $1 are passed to the backend as having type
'ival' resulting in code like `val.ival`.  This is troublesome in the
case of api.value.type=union, since in that the case the code this:

  %define api.value.type union
  %token <int> NUM
  %type <int> exp1 exp2
  exp1: NUM { $$ = $1; }
  exp2: NUM { $<int>$ = $<int>1; }

because in this case, since the backend does not know the symbol being
processed, it is forced to generate casts in both cases: *(int*)(&val)`.
This is unfortunate in the first case (exp1) where there is no reason
at all to use a cast instead of `val.NUM` and `val.exp1`.

So instead delegate the computation of the actual value type to the
backend: pass $<ival>$ as `symbol-number, ival` and $$ as
`symbol-number, MULL`, instead of passing `ival` before.

* src/scan-code.l (handle_action_dollar): Find the symbol the action
is about, not just its tyye.  Pass both symbol-number, and explicit
type tag ($<tag>n when there is one) to b4_lhs_value and b4_rhs_value.

* data/bison.m4 (b4_symbol_action): adjust to the new signature to
b4_dollar_pushdef.

* data/c-like.m4 (_b4_dollar_dollar, b4_dollar_pushdef): Accept the
symbol-number as new argument.

* data/c.m4 (b4_symbol_value): Accept the symbol-number as new
argument, and use it.
(b4_symbol_value_union): Accept the symbol-number as new
argument, and use it to prefer ready a union member rather than
casting the union.
* data/yacc.c (b4_lhs_value, b4_rhs_value): Accept the new
symbol-number argument.
Adjust uses of b4_dollar_pushdef.
* data/glr.c (b4_lhs_value, b4_rhs_value): Adjust.

* data/lalr1.cc (b4_symbol_value_template, b4_lhs_value): Adjust
to the new symbol-number argument.
* data/variant.hh (b4_symbol_value, b4_symbol_value_template): Accept
the new symbol-number argument.

* data/java.m4 (b4_symbol_value, b4_rhs_data): New.
(b4_rhs_value): Use them.
* data/lalr1.java: Adjust to b4_dollar_pushdef, and use b4_rhs_data.
This commit is contained in:
Akim Demaille
2018-12-03 07:03:29 +01:00
parent e40db8976c
commit c44a782a4e
10 changed files with 151 additions and 86 deletions
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25
src/scan-code.l
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@@ -627,10 +627,9 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
case LHS_REF:
{
if (!type_name)
type_name = symbol_list_n_type_name_get (rule, 0);
if (!type_name)
symbol_list *sym = symbol_list_n_get (rule, 0);
if (!type_name
&& !sym->content.sym->content->type_name)
{
if (union_seen | tag_seen)
{
@@ -649,7 +648,8 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
untyped_var_seen = true;
}
obstack_sgrow (&obstack_for_string, "]b4_lhs_value(");
obstack_printf (&obstack_for_string, "]b4_lhs_value(%d, ",
sym->content.sym->content->number);
obstack_quote (&obstack_for_string, type_name);
obstack_sgrow (&obstack_for_string, ")[");
rule->action_props.is_value_used = true;
@@ -661,9 +661,9 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
{
if (max_left_semantic_context < 1 - n)
max_left_semantic_context = 1 - n;
if (!type_name && 0 < n)
type_name = symbol_list_n_type_name_get (effective_rule, n);
if (!type_name)
symbol_list *sym = 0 < n ? symbol_list_n_get (effective_rule, n) : NULL;
if (!type_name
&& (!sym || !sym->content.sym->content->type_name))
{
if (union_seen | tag_seen)
complain (&dollar_loc, complaint,
@@ -674,12 +674,17 @@ handle_action_dollar (symbol_list *rule, char *text, location dollar_loc)
}
obstack_printf (&obstack_for_string,
"]b4_rhs_value(%d, %d, ", effective_rule_length, n);
"]b4_rhs_value(%d, %d, ",
effective_rule_length, n);
if (sym)
obstack_printf (&obstack_for_string, "%d, ", sym->content.sym->content->number);
else
obstack_sgrow (&obstack_for_string, "[], ");
obstack_quote (&obstack_for_string, type_name);
obstack_sgrow (&obstack_for_string, ")[");
if (0 < n)
{
symbol_list *sym = symbol_list_n_get (effective_rule, n);
if (muscle_percent_define_ifdef ("api.value.automove")
&& sym->action_props.is_value_used)
complain (&dollar_loc, Wother,