Optimize codegen for enums: no longer bother with a struct wrapper, but

just use a C enum type instead. This will make it easier to use
externally defined enums in the future.

6 files changed, 80 insertions, 34 deletions

diff --git a/src/compile.c b/src/compile.c
index ebd7b6ba..8671592e 100644
--- a/src/compile.c
+++ b/src/compile.c
@@ -1004,8 +1004,12 @@ CORD check_none(type_t *t, CORD value)
         return CORD_all("({(", value, ").length < 0;})");
     else if (t->tag == IntType || t->tag == ByteType || t->tag == StructType)
         return CORD_all("(", value, ").is_none");
-    else if (t->tag == EnumType)
-        return CORD_all("({(", value, ").$tag == 0;})");
+    else if (t->tag == EnumType) {
+        if (enum_has_fields(t))
+            return CORD_all("({(", value, ").$tag == 0;})");
+        else
+            return CORD_all("((", value, ") == 0)");
+    }
     print_err("Optional check not implemented for: ", type_to_str(t));
     return CORD_EMPTY;
 }
@@ -1066,7 +1070,13 @@ static CORD _compile_statement(env_t *env, ast_t *ast)
         }
 
         DeclareMatch(enum_t, subject_t, EnumType);
-        CORD code = CORD_all("WHEN(", compile_type(subject_t), ", ", compile(env, when->subject), ", _when_subject, {\n");
+
+        CORD code;
+        if (enum_has_fields(subject_t))
+            code = CORD_all("WHEN(", compile_type(subject_t), ", ", compile(env, when->subject), ", _when_subject, {\n");
+        else
+            code = CORD_all("switch(", compile(env, when->subject), ") {\n");
+
         for (when_clause_t *clause = when->clauses; clause; clause = clause->next) {
             if (clause->pattern->tag == Var) {
                 const char *clause_tag_name = Match(clause->pattern, Var)->name;
@@ -1148,7 +1158,7 @@ static CORD _compile_statement(env_t *env, ast_t *ast)
         } else {
             code = CORD_all(code, "default: errx(1, \"Invalid tag!\");\n");
         }
-        code = CORD_all(code, "\n})\n");
+        code = CORD_all(code, "\n}", enum_has_fields(subject_t) ? ")" : CORD_EMPTY, "\n");
         return code;
     }
     case DocTest: {
@@ -2669,8 +2679,10 @@ CORD compile_empty(type_t *t)
         assert(tag->type);
         if (Match(tag->type, StructType)->fields)
             return CORD_all("((", compile_type(t), "){.$tag=", String(tag->tag_value), ", .", tag->name, "=", compile_empty(tag->type), "})");
-        else
+        else if (enum_has_fields(t))
             return CORD_all("((", compile_type(t), "){.$tag=", String(tag->tag_value), "})");
+        else
+            return CORD_all("((", compile_type(t), ")", String(tag->tag_value), ")");
     }
     default: return CORD_EMPTY;
     }
@@ -3825,9 +3837,12 @@ CORD compile(env_t *env, ast_t *ast)
                     if (fielded_t->tag == PointerType) {
                         CORD fielded = compile_to_pointer_depth(env, f->fielded, 1, false);
                         return CORD_all("((", fielded, ")->$tag == ", tag_name, ")");
-                    } else {
+                    } else if (enum_has_fields(value_t)) {
                         CORD fielded = compile(env, f->fielded);
                         return CORD_all("((", fielded, ").$tag == ", tag_name, ")");
+                    } else {
+                        CORD fielded = compile(env, f->fielded);
+                        return CORD_all("((", fielded, ") == ", tag_name, ")");
                     }
                 }
             }
@@ -4708,15 +4723,26 @@ static void _make_typedefs(compile_typedef_info_t *info, ast_t *ast)
         *info->header = CORD_all(*info->header, "typedef struct ", struct_name, " ", type_name, ";\n");
     } else if (ast->tag == EnumDef) {
         DeclareMatch(def, ast, EnumDef);
-        CORD struct_name = namespace_name(info->env, info->env->namespace, CORD_all(def->name, "$$struct"));
-        CORD type_name = namespace_name(info->env, info->env->namespace, CORD_all(def->name, "$$type"));
-        *info->header = CORD_all(*info->header, "typedef struct ", struct_name, " ", type_name, ";\n");
-
+        bool has_any_tags_with_fields = false;
         for (tag_ast_t *tag = def->tags; tag; tag = tag->next) {
-            if (!tag->fields) continue;
-            CORD tag_struct = namespace_name(info->env, info->env->namespace, CORD_all(def->name, "$", tag->name, "$$struct"));
-            CORD tag_type = namespace_name(info->env, info->env->namespace, CORD_all(def->name, "$", tag->name, "$$type"));
-            *info->header = CORD_all(*info->header, "typedef struct ", tag_struct, " ", tag_type, ";\n");
+            has_any_tags_with_fields = has_any_tags_with_fields || (tag->fields != NULL);
+        }
+
+        if (has_any_tags_with_fields) {
+            CORD struct_name = namespace_name(info->env, info->env->namespace, CORD_all(def->name, "$$struct"));
+            CORD type_name = namespace_name(info->env, info->env->namespace, CORD_all(def->name, "$$type"));
+            *info->header = CORD_all(*info->header, "typedef struct ", struct_name, " ", type_name, ";\n");
+
+            for (tag_ast_t *tag = def->tags; tag; tag = tag->next) {
+                if (!tag->fields) continue;
+                CORD tag_struct = namespace_name(info->env, info->env->namespace, CORD_all(def->name, "$", tag->name, "$$struct"));
+                CORD tag_type = namespace_name(info->env, info->env->namespace, CORD_all(def->name, "$", tag->name, "$$type"));
+                *info->header = CORD_all(*info->header, "typedef struct ", tag_struct, " ", tag_type, ";\n");
+            }
+        } else {
+            CORD enum_name = namespace_name(info->env, info->env->namespace, CORD_all(def->name, "$$enum"));
+            CORD type_name = namespace_name(info->env, info->env->namespace, CORD_all(def->name, "$$type"));
+            *info->header = CORD_all(*info->header, "typedef enum ", enum_name, " ", type_name, ";\n");
         }
     } else if (ast->tag == LangDef) {
         DeclareMatch(def, ast, LangDef);
diff --git a/src/enums.c b/src/enums.c
index e391086e..2ff64ad3 100644
--- a/src/enums.c
+++ b/src/enums.c
@@ -86,32 +86,37 @@ CORD compile_enum_header(env_t *env, ast_t *ast)
 {
     DeclareMatch(def, ast, EnumDef);
     CORD all_defs = CORD_EMPTY;
-    CORD struct_name = namespace_name(env, env->namespace, CORD_all(def->name, "$$struct"));
     CORD none_name = namespace_name(env, env->namespace, CORD_all(def->name, "$none"));
-    CORD enum_def = CORD_all("struct ", struct_name, " {\n"
-                             "\tenum { ", none_name, "=0, ");
+    CORD enum_name = namespace_name(env, env->namespace, CORD_all(def->name, "$$enum"));
+    CORD enum_tags = CORD_all("{ ", none_name, "=0, ");
 
     bool has_any_tags_with_fields = false;
     for (tag_ast_t *tag = def->tags; tag; tag = tag->next) {
         CORD tag_name = namespace_name(env, env->namespace, CORD_all(def->name, "$tag$", tag->name));
-        enum_def = CORD_all(enum_def, tag_name);
-        if (tag->next) enum_def = CORD_all(enum_def, ", ");
+        enum_tags = CORD_all(enum_tags, tag_name);
+        if (tag->next) enum_tags = CORD_all(enum_tags, ", ");
         has_any_tags_with_fields = has_any_tags_with_fields || (tag->fields != NULL);
     }
-    enum_def = CORD_all(enum_def, "} $tag;\n");
-
-    if (has_any_tags_with_fields) {
-        enum_def = CORD_all(enum_def, "union {\n");
-        for (tag_ast_t *tag = def->tags; tag; tag = tag->next) {
-            if (!tag->fields) continue;
-            CORD field_def = compile_struct_header(env, WrapAST(ast, StructDef, .name=CORD_to_const_char_star(CORD_all(def->name, "$", tag->name)), .fields=tag->fields));
-            all_defs = CORD_all(all_defs, field_def);
-            CORD tag_type = namespace_name(env, env->namespace, CORD_all(def->name, "$", tag->name, "$$type"));
-            enum_def = CORD_all(enum_def, tag_type, " ", tag->name, ";\n");
-        }
-        enum_def = CORD_all(enum_def, "};\n");
+    enum_tags = CORD_all(enum_tags, " }");
+
+    if (!has_any_tags_with_fields) {
+        CORD enum_def = CORD_all("enum ", enum_name, " ", enum_tags, ";\n");
+        CORD info = namespace_name(env, env->namespace, CORD_all(def->name, "$$info"));
+        return CORD_all(enum_def, "extern const TypeInfo_t ", info, ";\n");
+    }
+
+    CORD struct_name = namespace_name(env, env->namespace, CORD_all(def->name, "$$struct"));
+    CORD enum_def = CORD_all("struct ", struct_name, " {\n"
+                             "enum ", enum_tags, " $tag;\n"
+                             "union {\n");
+    for (tag_ast_t *tag = def->tags; tag; tag = tag->next) {
+        if (!tag->fields) continue;
+        CORD field_def = compile_struct_header(env, WrapAST(ast, StructDef, .name=CORD_to_const_char_star(CORD_all(def->name, "$", tag->name)), .fields=tag->fields));
+        all_defs = CORD_all(all_defs, field_def);
+        CORD tag_type = namespace_name(env, env->namespace, CORD_all(def->name, "$", tag->name, "$$type"));
+        enum_def = CORD_all(enum_def, tag_type, " ", tag->name, ";\n");
     }
-    enum_def = CORD_all(enum_def, "};\n");
+    enum_def = CORD_all(enum_def, "};\n};\n");
     all_defs = CORD_all(all_defs, enum_def);
 
     CORD info = namespace_name(env, env->namespace, CORD_all(def->name, "$$info"));
diff --git a/src/structs.c b/src/structs.c
index b398b871..88de7aac 100644
--- a/src/structs.c
+++ b/src/structs.c
@@ -69,7 +69,7 @@ CORD compile_struct_header(env_t *env, ast_t *ast)
     CORD typeinfo_code = CORD_all("extern const TypeInfo_t ", typeinfo_name, ";\n");
     CORD optional_code = CORD_EMPTY;
     if (!def->opaque) {
-        optional_code = CORD_all("DEFINE_OPTIONAL_TYPE(", compile_type(t), ", ", unpadded_size, ",",
+        optional_code = CORD_all("DEFINE_OPTIONAL_TYPE(", compile_type(t), ", ", unpadded_size, ", ",
                                  namespace_name(env, env->namespace, CORD_all("$Optional", def->name, "$$type")), ");\n");
     }
     return CORD_all(struct_code, optional_code, typeinfo_code);
diff --git a/src/typecheck.c b/src/typecheck.c
index b98cb84b..6fdfb1d8 100644
--- a/src/typecheck.c
+++ b/src/typecheck.c
@@ -397,7 +397,9 @@ void bind_statement(env_t *env, ast_t *statement)
         assert(type);
         tag_t *tags = NULL;
         int64_t next_tag = 1;
+        bool has_any_tags_with_fields = false;
         for (tag_ast_t *tag_ast = def->tags; tag_ast; tag_ast = tag_ast->next) {
+            has_any_tags_with_fields = has_any_tags_with_fields || tag_ast->fields;
             arg_t *fields = NULL;
             for (arg_ast_t *field_ast = tag_ast->fields; field_ast; field_ast = field_ast->next) {
                 type_t *field_t = get_arg_ast_type(env, field_ast);
@@ -437,10 +439,13 @@ void bind_statement(env_t *env, ast_t *statement)
             if (Match(tag->type, StructType)->fields) { // Constructor:
                 type_t *constructor_t = Type(FunctionType, .args=Match(tag->type, StructType)->fields, .ret=type);
                 set_binding(ns_env, tag->name, constructor_t, namespace_name(env, env->namespace, CORD_all(def->name, "$tagged$", tag->name)));
-            } else { // Empty singleton value:
+            } else if (has_any_tags_with_fields) { // Empty singleton value:
                 CORD code = CORD_all("((", namespace_name(env, env->namespace, CORD_all(def->name, "$$type")), "){",
                                      namespace_name(env, env->namespace, CORD_all(def->name, "$tag$", tag->name)), "})");
                 set_binding(ns_env, tag->name, type, code);
+            } else {
+                CORD code = namespace_name(env, env->namespace, CORD_all(def->name, "$tag$", tag->name));
+                set_binding(ns_env, tag->name, type, code);
             }
             Table$str_set(env->types, String(def->name, "$", tag->name), tag->type);
         }
diff --git a/src/types.c b/src/types.c
index 91848bef..1a2405d4 100644
--- a/src/types.c
+++ b/src/types.c
@@ -836,4 +836,13 @@ type_t *_make_function_type(type_t *ret, int n, arg_t args[n])
     return Type(FunctionType, .ret=ret, .args=&arg_pointers[0]);
 }
 
+PUREFUNC bool enum_has_fields(type_t *t)
+{
+    for (tag_t *e_tag = Match(t, EnumType)->tags; e_tag; e_tag = e_tag->next) {
+        if (e_tag->type != NULL && Match(e_tag->type, StructType)->fields)
+            return true;
+    }
+    return false;
+}
+
 // vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0
diff --git a/src/types.h b/src/types.h
index 33e54ff5..3b789560 100644
--- a/src/types.h
+++ b/src/types.h
@@ -157,5 +157,6 @@ PUREFUNC type_t *non_optional(type_t *t);
 type_t *get_field_type(type_t *t, const char *field_name);
 PUREFUNC type_t *get_iterated_type(type_t *t);
 type_t *_make_function_type(type_t *ret, int n, arg_t args[n]);
+PUREFUNC bool enum_has_fields(type_t *t);
 
 // vim: ts=4 sw=0 et cino=L2,l1,(0,W4,m1,\:0