commit d4b03b17f0bac5d28dd8f2ff69b4f5487454a299
parent 445181f1ab84c9ab661ad2c9f313cbb42e9007bf
Author: Bor Grošelj Simić <bgs@turminal.net>
Date: Thu, 2 Jun 2022 00:33:39 +0200
simplify and generalize declaration resolution
Previous version of declaration resolution was algorithmically correct,
but implemented in a pretty convoluted way, which made it difficult to
understand and reason about. It mainly addressed the needs of
(co)recursive type resolution and all other functionality was sort of
glued onto it with limited success.
This patch makes "scan_decl_finish" into merely a wrapper that takes
care of context setup and teardown and detects circular dependencies,
the main resolution functionality is left to arbitrary resolver
functions that can be passed to it.
This will among other things allow us to use the mechanism for enum
alias resolution which is a separate procedure, but needs to take care
of context setup and circular dependencies in the same way.
Signed-off-by: Bor Grošelj Simić <bgs@turminal.net>
Diffstat:
3 files changed, 89 insertions(+), 52 deletions(-)
diff --git a/include/check.h b/include/check.h
@@ -136,8 +136,20 @@ struct incomplete_declaration {
void mkident(struct context *ctx, struct identifier *out,
const struct identifier *in);
-const struct scope_object *scan_decl_finish(struct context *ctx,
- const struct scope_object *obj, struct dimensions *dim);
+typedef const struct scope_object *(*resolvefn)(struct context *,
+ const struct scope_object *obj);
+
+const struct scope_object *resolve_dimensions(struct context *ctx,
+ const struct scope_object *obj);
+
+const struct scope_object *resolve_type(struct context *ctx,
+ const struct scope_object *obj);
+
+const struct scope_object *resolve_decl(struct context *ctx,
+ const struct scope_object *obj);
+
+const struct scope_object *wrap_resolver(struct context *ctx,
+ const struct scope_object *obj, resolvefn resolver);
struct scope *check(struct type_store *ts,
bool is_test,
diff --git a/src/check.c b/src/check.c
@@ -148,7 +148,7 @@ check_expr_access(struct context *ctx,
}
if (obj->otype == O_SCAN) {
// complete the declaration first
- obj = scan_decl_finish(ctx, obj, NULL);
+ obj = wrap_resolver(ctx, obj, resolve_decl);
}
switch (obj->otype) {
@@ -3483,8 +3483,9 @@ scan_global(struct context *ctx, const struct ast_global_decl *decl)
}
const struct scope_object *
-scan_enum_field(struct context *ctx, struct incomplete_declaration *idecl)
+resolve_enum_field(struct context *ctx, const struct scope_object *obj)
{
+ struct incomplete_declaration *idecl = (struct incomplete_declaration*)obj;
assert(ctx->resolving_enum == NULL);
assert(idecl->type == IDECL_ENUM_FLD);
@@ -3534,7 +3535,7 @@ scan_enum_field(struct context *ctx, struct incomplete_declaration *idecl)
&idecl->obj.lnext->name);
if (obj->otype == O_SCAN) {
// complete previous value first
- obj = scan_decl_finish(ctx, obj, NULL);
+ obj = wrap_resolver(ctx, obj, resolve_enum_field);
}
}
value->type = EXPR_CONSTANT;
@@ -3557,7 +3558,7 @@ scan_enum_field(struct context *ctx, struct incomplete_declaration *idecl)
for (struct identifiers *id = type->_enum.aliases; id; id = id->next) {
const struct scope_object *obj = scope_lookup(ctx->scope, &id->ident);
if (obj->otype == O_SCAN) {
- obj = scan_decl_finish(ctx, obj, NULL);
+ obj = wrap_resolver(ctx, obj, resolve_decl);
}
struct identifier alias_ident, alias_name = {
.name = name.name,
@@ -3630,7 +3631,7 @@ enum_alias_list(struct context *ctx, const struct scope_object *obj,
const struct scope_object *alias =
scope_lookup(ctx->scope, &ids->ident);
if (alias->otype == O_SCAN) {
- alias = scan_decl_finish(ctx, alias, NULL);
+ alias = wrap_resolver(ctx, alias, resolve_type);
}
for (obj = type->_enum.values->objects;
obj; obj = obj->lnext) {
@@ -3652,8 +3653,9 @@ enum_alias_list(struct context *ctx, const struct scope_object *obj,
}
static const struct scope_object *
-scan_enum_type(struct context *ctx, struct incomplete_declaration *idecl)
+resolve_enum_type(struct context *ctx, const struct scope_object *obj)
{
+ struct incomplete_declaration *idecl = (struct incomplete_declaration*)obj;
assert(idecl->type == IDECL_ENUM_TYPE);
struct type *type = (struct type *)type_store_lookup_atype(ctx->store,
idecl->decl.type.type);
@@ -3665,20 +3667,40 @@ scan_enum_type(struct context *ctx, struct incomplete_declaration *idecl)
&idecl->obj.ident, &idecl->obj.name, type, NULL);
}
-static const struct scope_object *
-scan_type(struct context *ctx, struct incomplete_declaration *idecl,
- struct dimensions *dim)
+const struct scope_object *
+resolve_dimensions(struct context *ctx, const struct scope_object *obj)
{
- if (dim) {
- // the caller is only interested in this type's dimensions
- *dim = type_store_lookup_dimensions(ctx->store,
+ struct incomplete_declaration *idecl = (struct incomplete_declaration*)obj;
+ struct dimensions dim = type_store_lookup_dimensions(ctx->store,
idecl->decl.type.type);
- return NULL;
+ ((struct scope_object *)obj)->type = xcalloc(1, sizeof(struct type));
+ *(struct type *)obj->type = (struct type){
+ .size = dim.size,
+ .align = dim.align,
+ };
+ return &idecl->obj;
+}
+
+const struct scope_object *
+resolve_type(struct context *ctx, const struct scope_object *obj)
+{
+ struct incomplete_declaration *idecl = (struct incomplete_declaration*)obj;
+ if (idecl->type == IDECL_ENUM_TYPE) {
+ return resolve_enum_type(ctx, obj);
+ }
+ if (idecl->type != IDECL_DECL || idecl->decl.decl_type != AST_DECL_TYPE) {
+ struct location *loc;
+ if (idecl->type == IDECL_ENUM_FLD) {
+ loc = &idecl->field->type->loc;
+ } else {
+ loc = &idecl->decl.loc;
+ }
+ expect(loc, false, "'%s' is not a type",
+ identifier_unparse(&idecl->obj.name));
}
// 1. compute type dimensions
- struct dimensions _dim =
- type_store_lookup_dimensions(ctx->store,
+ struct dimensions dim = type_store_lookup_dimensions(ctx->store,
idecl->decl.type.type);
handle_errors(ctx->errors);
@@ -3697,8 +3719,8 @@ scan_type(struct context *ctx, struct incomplete_declaration *idecl,
.type = NULL,
.exported = idecl->decl.exported,
},
- .size = _dim.size,
- .align = _dim.align,
+ .size = dim.size,
+ .align = dim.align,
.flags = idecl->decl.type.type->flags,
};
@@ -3775,8 +3797,34 @@ scan_decl_start(struct context *ctx, struct scope *imports, struct ast_decl *dec
}
const struct scope_object *
-scan_decl_finish(struct context *ctx, const struct scope_object *obj,
- struct dimensions *dim)
+resolve_decl(struct context *ctx, const struct scope_object *obj)
+{
+ struct incomplete_declaration *idecl = (struct incomplete_declaration*)obj;
+ switch (idecl->type) {
+ case IDECL_ENUM_FLD:
+ return resolve_enum_field(ctx, obj);
+ case IDECL_ENUM_TYPE:
+ return resolve_enum_type(ctx, obj);
+ case IDECL_DECL:
+ break;
+ }
+
+ switch (idecl->decl.decl_type) {
+ case AST_DECL_CONST:
+ return scan_const(ctx, &idecl->decl.constant);
+ case AST_DECL_GLOBAL:
+ return scan_global(ctx, &idecl->decl.global);
+ case AST_DECL_FUNC:
+ return scan_function(ctx, &idecl->decl.function);
+ case AST_DECL_TYPE:
+ return resolve_type(ctx, obj);
+ }
+ abort();
+}
+
+const struct scope_object *
+wrap_resolver(struct context *ctx, const struct scope_object *obj,
+ resolvefn resolver)
{
// save current subunit and enum context
struct scope *enum_scope = ctx->resolving_enum;
@@ -3807,31 +3855,7 @@ scan_decl_finish(struct context *ctx, const struct scope_object *obj,
}
idecl->in_progress = true;
- switch (idecl->type) {
- case IDECL_ENUM_FLD:
- obj = scan_enum_field(ctx, idecl);
- goto exit;
- case IDECL_ENUM_TYPE:
- obj = scan_enum_type(ctx, idecl);
- goto exit;
- case IDECL_DECL:
- break;
- }
-
- switch (idecl->decl.decl_type) {
- case AST_DECL_CONST:
- obj = scan_const(ctx, &idecl->decl.constant);
- break;
- case AST_DECL_GLOBAL:
- obj = scan_global(ctx, &idecl->decl.global);
- break;
- case AST_DECL_FUNC:
- obj = scan_function(ctx, &idecl->decl.function);
- break;
- case AST_DECL_TYPE:
- obj = scan_type(ctx, idecl, dim);
- break;
- }
+ obj = resolver(ctx, &idecl->obj);
exit:
// load stored context
ctx->unit->parent = subunit;
@@ -4062,7 +4086,7 @@ check_internal(struct type_store *ts,
ctx.resolving_enum = NULL;
for (const struct scope_object *obj = ctx.scope->objects;
obj && obj->otype == O_SCAN; obj = obj->lnext) {
- scan_decl_finish(&ctx, obj, NULL);
+ wrap_resolver(&ctx, obj, resolve_decl);
assert(ctx.resolving_enum == NULL);
}
diff --git a/src/type_store.c b/src/type_store.c
@@ -645,17 +645,18 @@ type_init_from_atype(struct type_store *store,
if (obj->otype == O_SCAN) {
// an incomplete declaration was encountered
- struct dimensions dim = {0};
struct incomplete_declaration *idecl =
(struct incomplete_declaration *)obj;
if (size_only && idecl->type == IDECL_DECL) {
- scan_decl_finish(store->check_context, obj, &dim);
- type->size = dim.size;
- type->align = dim.align;
+ obj = wrap_resolver(store->check_context, obj,
+ resolve_dimensions);
+ type->size = obj->type->size;
+ type->align = obj->type->align;
break;
}
// complete it first and then proceed normally
- obj = scan_decl_finish(store->check_context, obj, NULL);
+ obj = wrap_resolver(store->check_context,
+ obj, resolve_type);
}
if (obj->otype != O_TYPE) {
