From 438faa73651bb4d700dd9d6eb589976402da10eb Mon Sep 17 00:00:00 2001
From: nsfisis <nsfisis@gmail.com>
Date: Sun, 4 May 2025 19:18:35 +0900
Subject: struct sizeof

---
 main.c       | 74 ++++++++++++++++++++++++++++++++++++++++++++++---
 tests/028.sh | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 160 insertions(+), 4 deletions(-)
 create mode 100644 tests/028.sh

diff --git a/main.c b/main.c
index dad36c1..5e7a8d4 100644
--- a/main.c
+++ b/main.c
@@ -333,6 +333,9 @@ int type_is_unsized_type(TYPE* ty) {
     return ty->kind != TY_VOID;
 }
 
+int type_sizeof_struct(TYPE* ty);
+int type_alignof_struct(TYPE* ty);
+
 int type_sizeof(TYPE* ty) {
     if (!type_is_unsized_type(ty)) {
         fatal_error("type_sizeof: type size cannot be determined");
@@ -347,7 +350,25 @@ int type_sizeof(TYPE* ty) {
     } else if (ty->kind == TY_LONG) {
         return 8;
     } else {
-        todo();
+        return type_sizeof_struct(ty);
+    }
+}
+
+int type_alignof(TYPE* ty) {
+    if (!type_is_unsized_type(ty)) {
+        fatal_error("type_alignof: type size cannot be determined");
+    }
+
+    if (ty->kind == TY_PTR) {
+        return 8;
+    } else if (ty->kind == TY_CHAR) {
+        return 1;
+    } else if (ty->kind == TY_INT) {
+        return 4;
+    } else if (ty->kind == TY_LONG) {
+        return 8;
+    } else {
+        return type_alignof_struct(ty);
     }
 }
 
@@ -458,6 +479,38 @@ AST* ast_new_assign_expr(int op, AST* lhs, AST* rhs) {
     return e;
 }
 
+int type_sizeof_struct(TYPE* ty) {
+    int next_offset = 0;
+    int struct_align = 0;
+
+    AST* member = ty->members->next;
+    while (member) {
+        int size = type_sizeof(member->ty);
+        int align = type_alignof(member->ty);
+
+        if (next_offset % align != 0) {
+            int padding = align - next_offset % align;
+            next_offset += padding;
+        }
+        next_offset += size;
+        if (struct_align < align) {
+            struct_align = align;
+        }
+
+        member = member->next;
+    }
+    if (next_offset % struct_align != 0) {
+        int padding = struct_align - next_offset % struct_align;
+        next_offset += padding;
+    }
+    return next_offset;
+}
+
+int type_alignof_struct(TYPE* ty) {
+    todo();
+    return 0;
+}
+
 #define LVAR_MAX 32
 
 typedef struct LVar {
@@ -981,12 +1034,25 @@ AST* parse_struct_members(PARSER* p) {
 AST* parse_struct_decl_or_def(PARSER* p) {
     expect(p, TK_K_STRUCT);
     char* name = parse_ident(p);
-    p->structs[p->n_structs].name = name;
-    p->n_structs += 1;
+    int struct_index;
+    for (struct_index = 0; struct_index < p->n_structs; struct_index++) {
+        if (strcmp(name, p->structs[struct_index].name) == 0) {
+            break;
+        }
+    }
+    if (struct_index == p->n_structs) {
+        p->structs[struct_index].name = name;
+        p->n_structs += 1;
+    }
     if (peek_token(p)->kind == TK_SEMICOLON) {
         next_token(p);
         return ast_new(AST_STRUCT_DECL);
     }
+    if (p->structs[struct_index].node1) {
+        char buf[1024];
+        sprintf(buf, "parse_struct_decl_or_def: struct %s redefined", name);
+        fatal_error(buf);
+    }
     expect(p, TK_BRACE_L);
     AST* members = parse_struct_members(p);
     expect(p, TK_BRACE_R);
@@ -994,7 +1060,7 @@ AST* parse_struct_decl_or_def(PARSER* p) {
     AST* s = ast_new(AST_STRUCT_DEF);
     s->name = name;
     s->node1 = members;
-    p->structs[p->n_structs - 1].node1 = members;
+    p->structs[struct_index].node1 = members;
     return s;
 }
 
diff --git a/tests/028.sh b/tests/028.sh
new file mode 100644
index 0000000..f5f7a6d
--- /dev/null
+++ b/tests/028.sh
@@ -0,0 +1,90 @@
+set -e
+
+cat <<'EOF' > expected
+sizeof(struct Token) = 16
+sizeof(struct Define) = 16
+sizeof(struct Type) = 24
+sizeof(struct AstNode) = 128
+sizeof(struct LVar) = 16
+sizeof(struct Func) = 16
+sizeof(struct Parser) = 64
+sizeof(struct CodeGen) = 16
+EOF
+bash ../../test_diff.sh <<'EOF'
+struct Token {
+    int kind;
+    char* value;
+};
+
+struct Define {
+    char* from;
+    struct Token* to;
+};
+
+struct AstNode;
+
+struct Type {
+    int kind;
+    struct Type* to;
+    struct AstNode* members;
+};
+
+struct AstNode {
+    int kind;
+    struct AstNode* next;
+    struct AstNode* last;
+    char* name;
+    struct AstNode* func_params;
+    struct AstNode* func_body;
+    int int_value;
+    struct AstNode* expr1;
+    struct AstNode* expr2;
+    struct AstNode* expr3;
+    int op;
+    struct Type* ty;
+    int var_index;
+    struct AstNode* node1;
+    struct AstNode* node2;
+    char** str_literals;
+};
+
+struct LVar {
+    char* name;
+    struct Type* ty;
+};
+
+struct Func {
+    char* name;
+    struct Type* ty;
+};
+
+struct Parser {
+    struct Token* tokens;
+    int pos;
+    struct LVar* locals;
+    int n_locals;
+    struct Func* funcs;
+    int n_funcs;
+    char** str_literals;
+    int n_str_literals;
+};
+
+struct CodeGen {
+    int next_label;
+    int* loop_labels;
+};
+
+int printf();
+
+int main() {
+    printf("sizeof(struct Token) = %d\n", sizeof(struct Token));
+    printf("sizeof(struct Define) = %d\n", sizeof(struct Define));
+    printf("sizeof(struct Type) = %d\n", sizeof(struct Type));
+    printf("sizeof(struct AstNode) = %d\n", sizeof(struct AstNode));
+    printf("sizeof(struct LVar) = %d\n", sizeof(struct LVar));
+    printf("sizeof(struct Func) = %d\n", sizeof(struct Func));
+    printf("sizeof(struct Parser) = %d\n", sizeof(struct Parser));
+    printf("sizeof(struct CodeGen) = %d\n", sizeof(struct CodeGen));
+    return 0;
+}
+EOF
-- 
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