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Fix code generation for nested unions.

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When a union is nested inside another union, it must be enclosed in a struct
so that its "which" member is not overlapping with its other members.
This commit is contained in:
Jason Heeris 2021-01-14 10:41:17 +08:00
parent 9053ebe6ee
commit 6661fc9d2d
1 changed files with 25 additions and 6 deletions
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31
compiler/capnpc-c.c
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@ -718,7 +718,7 @@ static void declare_slot(struct strings *s, struct field *f) {
} }
} }
static void define_group(struct strings *s, struct node *n, const char *group_name); static void define_group(struct strings *s, struct node *n, const char *group_name, bool enclose_unions);
static void do_union(struct strings *s, struct node *n, struct field *first_field, const char *union_name) { static void do_union(struct strings *s, struct node *n, struct field *first_field, const char *union_name) {
int tagoff = 2 * n->n._struct.discriminantOffset; int tagoff = 2 * n->n._struct.discriminantOffset;
@ -774,7 +774,10 @@ static void do_union(struct strings *s, struct node *n, struct field *first_fiel
str_addf(&s->get, "%scase %s_%s:\n", s->ftab.str, n->name.str, field_name(f)); str_addf(&s->get, "%scase %s_%s:\n", s->ftab.str, n->name.str, field_name(f));
str_addf(&s->set, "%scase %s_%s:\n", s->ftab.str, n->name.str, field_name(f)); str_addf(&s->set, "%scase %s_%s:\n", s->ftab.str, n->name.str, field_name(f));
str_add(&s->ftab, "\t", -1); str_add(&s->ftab, "\t", -1);
define_group(s, f->group, field_name(f)); // When we add a union inside a union, we need to enclose it in its
// own struct so that its members do not overwrite its own
// discriminant.
define_group(s, f->group, field_name(f), true);
str_addf(&s->get, "%sbreak;\n", s->ftab.str); str_addf(&s->get, "%sbreak;\n", s->ftab.str);
str_addf(&s->set, "%sbreak;\n", s->ftab.str); str_addf(&s->set, "%sbreak;\n", s->ftab.str);
str_setlen(&s->ftab, s->ftab.len-1); str_setlen(&s->ftab, s->ftab.len-1);
@ -821,7 +824,7 @@ static void define_field(struct strings *s, struct field *f) {
break; break;
case Field_group: case Field_group:
define_group(s, f->group, field_name(f)); define_group(s, f->group, field_name(f), false);
break; break;
} }
} }
@ -862,7 +865,7 @@ static void define_setter_functions(struct node* node, struct field* field,
str_release(&setter_body); str_release(&setter_body);
} }
static void define_group(struct strings *s, struct node *n, const char *group_name) { static void define_group(struct strings *s, struct node *n, const char *group_name, bool enclose_unions) {
struct field *f; struct field *f;
int flen = capn_len(n->n._struct.fields); int flen = capn_len(n->n._struct.fields);
int ulen = n->n._struct.discriminantCount; int ulen = n->n._struct.discriminantCount;
@ -916,7 +919,17 @@ static void define_group(struct strings *s, struct node *n, const char *group_na
} }
if (ulen > 0) { if (ulen > 0) {
do_union(s, n, f, named_union ? group_name : NULL); if (enclose_unions)
{
// When we are already inside a union, so we need to enclose the union
// with its disciminant.
str_addf(&s->decl, "%scapnp_nowarn struct {\n", s->dtab.str);
str_add(&s->dtab, "\t", 1);
}
const bool keep_union_name = named_union && !enclose_unions;
do_union(s, n, f, keep_union_name ? group_name : NULL);
while (f < n->fields + flen && in_union(f)) while (f < n->fields + flen && in_union(f))
f++; f++;
@ -925,6 +938,12 @@ static void define_group(struct strings *s, struct node *n, const char *group_na
for (;f < n->fields + flen; f++) { for (;f < n->fields + flen; f++) {
define_field(s, f); define_field(s, f);
} }
if (enclose_unions)
{
str_setlen(&s->dtab, s->dtab.len-1);
str_addf(&s->decl, "%s} %s;\n", s->dtab.str, group_name);
}
} }
if (named_struct) { if (named_struct) {
@ -956,7 +975,7 @@ static void define_struct(struct node *n) {
str_add(&s.ftab, "\t", -1); str_add(&s.ftab, "\t", -1);
str_add(&s.var, "s->", -1); str_add(&s.var, "s->", -1);
define_group(&s, n, NULL); define_group(&s, n, NULL, false);
str_add(&HDR, s.enums.str, s.enums.len); str_add(&HDR, s.enums.str, s.enums.len);