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-rw-r--r--codegen.c439
1 files changed, 439 insertions, 0 deletions
diff --git a/codegen.c b/codegen.c
new file mode 100644
index 0000000..26e7604
--- /dev/null
+++ b/codegen.c
@@ -0,0 +1,439 @@
+enum GenMode {
+ GenMode_lval,
+ GenMode_rval,
+};
+typedef enum GenMode GenMode;
+
+struct CodeGen {
+ int next_label;
+ int* loop_labels;
+};
+typedef struct CodeGen CodeGen;
+
+CodeGen* codegen_new() {
+ CodeGen* g = calloc(1, sizeof(CodeGen));
+ g->next_label = 1;
+ g->loop_labels = calloc(1024, sizeof(int));
+ return g;
+}
+
+int codegen_new_label(CodeGen* g) {
+ int new_label = g->next_label;
+ ++g->next_label;
+ return new_label;
+}
+
+void codegen_expr(CodeGen* g, AstNode* ast, GenMode gen_mode);
+void codegen_stmt(CodeGen* g, AstNode* ast);
+
+const char* param_reg(int n) {
+ if (n == 0) {
+ return "rdi";
+ } else if (n == 1) {
+ return "rsi";
+ } else if (n == 2) {
+ return "rdx";
+ } else if (n == 3) {
+ return "rcx";
+ } else if (n == 4) {
+ return "r8";
+ } else if (n == 5) {
+ return "r9";
+ } else {
+ unreachable();
+ }
+}
+
+void codegen_func_prologue(CodeGen* g, AstNode* ast) {
+ printf(" push rbp\n");
+ printf(" mov rbp, rsp\n");
+ int i;
+ for (i = 0; i < ast->node_params->node_len; ++i) {
+ printf(" push %s\n", param_reg(i));
+ }
+ printf(" sub rsp, %d\n", 8 * LVAR_MAX);
+}
+
+void codegen_func_epilogue(CodeGen* g, AstNode* ast) {
+ printf(" mov rsp, rbp\n");
+ printf(" pop rbp\n");
+ printf(" ret\n");
+}
+
+void codegen_int_expr(CodeGen* g, AstNode* ast) {
+ printf(" push %d\n", ast->node_int_value);
+}
+
+void codegen_str_expr(CodeGen* g, AstNode* ast) {
+ printf(" mov rax, OFFSET FLAG:.Lstr__%d\n", ast->node_idx);
+ printf(" push rax\n");
+}
+
+void codegen_unary_expr(CodeGen* g, AstNode* ast) {
+ codegen_expr(g, ast->node_operand, GenMode_rval);
+ if (ast->node_op == TokenKind_not) {
+ printf(" pop rax\n");
+ printf(" mov rdi, 0\n");
+ printf(" cmp rax, rdi\n");
+ printf(" sete al\n");
+ printf(" movzb rax, al\n");
+ printf(" push rax\n");
+ } else {
+ unreachable();
+ }
+}
+
+void codegen_ref_expr(CodeGen* g, AstNode* ast, GenMode gen_mode) {
+ codegen_expr(g, ast->node_operand, GenMode_lval);
+}
+
+void codegen_lval2rval(Type* ty) {
+ int size = type_sizeof(ty);
+
+ printf(" pop rax\n");
+ if (size == 1) {
+ printf(" movsx rax, BYTE PTR [rax]\n");
+ } else if (size == 4) {
+ printf(" movsxd rax, DWORD PTR [rax]\n");
+ } else {
+ printf(" mov rax, [rax]\n");
+ }
+ printf(" push rax\n");
+}
+
+void codegen_deref_expr(CodeGen* g, AstNode* ast, GenMode gen_mode) {
+ codegen_expr(g, ast->node_operand, GenMode_rval);
+ if (gen_mode == GenMode_rval) {
+ codegen_lval2rval(ast->node_operand->ty->to);
+ }
+}
+
+void codegen_logical_expr(CodeGen* g, AstNode* ast) {
+ int label = codegen_new_label(g);
+
+ if (ast->node_op == TokenKind_andand) {
+ codegen_expr(g, ast->node_lhs, GenMode_rval);
+ printf(" pop rax\n");
+ printf(" cmp rax, 0\n");
+ printf(" je .Lelse%d\n", label);
+ codegen_expr(g, ast->node_rhs, GenMode_rval);
+ printf(" jmp .Lend%d\n", label);
+ printf(".Lelse%d:\n", label);
+ printf(" push 0\n");
+ printf(".Lend%d:\n", label);
+ } else {
+ codegen_expr(g, ast->node_lhs, GenMode_rval);
+ printf(" pop rax\n");
+ printf(" cmp rax, 0\n");
+ printf(" je .Lelse%d\n", label);
+ printf(" push 1\n");
+ printf(" jmp .Lend%d\n", label);
+ printf(".Lelse%d:\n", label);
+ codegen_expr(g, ast->node_rhs, GenMode_rval);
+ printf(".Lend%d:\n", label);
+ }
+}
+
+void codegen_binary_expr(CodeGen* g, AstNode* ast, GenMode gen_mode) {
+ codegen_expr(g, ast->node_lhs, gen_mode);
+ codegen_expr(g, ast->node_rhs, gen_mode);
+ printf(" pop rdi\n");
+ printf(" pop rax\n");
+ if (ast->node_op == TokenKind_plus) {
+ printf(" add rax, rdi\n");
+ } else if (ast->node_op == TokenKind_minus) {
+ printf(" sub rax, rdi\n");
+ } else if (ast->node_op == TokenKind_star) {
+ printf(" imul rax, rdi\n");
+ } else if (ast->node_op == TokenKind_slash) {
+ printf(" cqo\n");
+ printf(" idiv rdi\n");
+ } else if (ast->node_op == TokenKind_percent) {
+ printf(" cqo\n");
+ printf(" idiv rdi\n");
+ printf(" mov rax, rdx\n");
+ } else if (ast->node_op == TokenKind_eq) {
+ printf(" cmp rax, rdi\n");
+ printf(" sete al\n");
+ printf(" movzb rax, al\n");
+ } else if (ast->node_op == TokenKind_ne) {
+ printf(" cmp rax, rdi\n");
+ printf(" setne al\n");
+ printf(" movzb rax, al\n");
+ } else if (ast->node_op == TokenKind_lt) {
+ printf(" cmp rax, rdi\n");
+ printf(" setl al\n");
+ printf(" movzb rax, al\n");
+ } else if (ast->node_op == TokenKind_le) {
+ printf(" cmp rax, rdi\n");
+ printf(" setle al\n");
+ printf(" movzb rax, al\n");
+ } else {
+ unreachable();
+ }
+ printf(" push rax\n");
+}
+
+void codegen_assign_expr(CodeGen* g, AstNode* ast) {
+ codegen_expr(g, ast->node_lhs, GenMode_lval);
+ codegen_expr(g, ast->node_rhs, GenMode_rval);
+ if (ast->node_op == TokenKind_assign) {
+ } else if (ast->node_op == TokenKind_assign_add) {
+ printf(" pop rdi\n");
+ printf(" push [rsp]\n");
+ codegen_lval2rval(ast->node_lhs->ty);
+ printf(" pop rax\n");
+ printf(" add rax, rdi\n");
+ printf(" push rax\n");
+ } else if (ast->node_op == TokenKind_assign_sub) {
+ printf(" pop rdi\n");
+ printf(" push [rsp]\n");
+ codegen_lval2rval(ast->node_lhs->ty);
+ printf(" pop rax\n");
+ printf(" sub rax, rdi\n");
+ printf(" push rax\n");
+ } else {
+ unreachable();
+ }
+ printf(" pop rdi\n");
+ printf(" pop rax\n");
+ if (type_sizeof(ast->node_lhs->ty) == 1) {
+ printf(" mov BYTE PTR [rax], dil\n");
+ } else if (type_sizeof(ast->node_lhs->ty) == 4) {
+ printf(" mov DWORD PTR [rax], edi\n");
+ } else {
+ printf(" mov [rax], rdi\n");
+ }
+ printf(" push rdi\n");
+}
+
+void codegen_func_call(CodeGen* g, AstNode* ast) {
+ String* func_name = &ast->name;
+ AstNode* args = ast->node_args;
+ int i;
+ for (i = 0; i < args->node_len; ++i) {
+ AstNode* arg = args->node_items + i;
+ codegen_expr(g, arg, GenMode_rval);
+ }
+ for (i = args->node_len - 1; i >= 0; --i) {
+ printf(" pop %s\n", param_reg(i));
+ }
+
+ int label = codegen_new_label(g);
+
+ printf(" mov rax, rsp\n");
+ printf(" and rax, 15\n");
+ printf(" cmp rax, 0\n");
+ printf(" je .Laligned%d\n", label);
+
+ printf(" mov rax, 0\n");
+ printf(" sub rsp, 8\n");
+ printf(" call %.*s\n", func_name->len, func_name->data);
+ printf(" add rsp, 8\n");
+ printf(" push rax\n");
+
+ printf(" jmp .Lend%d\n", label);
+ printf(".Laligned%d:\n", label);
+
+ printf(" mov rax, 0\n");
+ printf(" call %.*s\n", func_name->len, func_name->data);
+ printf(" push rax\n");
+
+ printf(".Lend%d:\n", label);
+}
+
+void codegen_lvar(CodeGen* g, AstNode* ast, GenMode gen_mode) {
+ int offset = 8 + ast->node_idx * 8;
+ printf(" mov rax, rbp\n");
+ printf(" sub rax, %d\n", offset);
+ printf(" push rax\n");
+ if (gen_mode == GenMode_rval) {
+ codegen_lval2rval(ast->ty);
+ }
+}
+
+void codegen_gvar(CodeGen* g, AstNode* ast, GenMode gen_mode) {
+ if (gen_mode == GenMode_lval) {
+ fatal_error("unimplemented");
+ }
+ if (ast->ty->kind != TypeKind_ptr) {
+ fatal_error("unimplemented");
+ }
+ printf(" mov rax, QWORD PTR %.*s[rip]\n", ast->name.len, ast->name.data);
+ printf(" push rax\n");
+}
+
+void codegen_expr(CodeGen* g, AstNode* ast, GenMode gen_mode) {
+ if (ast->kind == AstNodeKind_int_expr) {
+ codegen_int_expr(g, ast);
+ } else if (ast->kind == AstNodeKind_str_expr) {
+ codegen_str_expr(g, ast);
+ } else if (ast->kind == AstNodeKind_unary_expr) {
+ codegen_unary_expr(g, ast);
+ } else if (ast->kind == AstNodeKind_ref_expr) {
+ codegen_ref_expr(g, ast, gen_mode);
+ } else if (ast->kind == AstNodeKind_deref_expr) {
+ codegen_deref_expr(g, ast, gen_mode);
+ } else if (ast->kind == AstNodeKind_binary_expr) {
+ codegen_binary_expr(g, ast, gen_mode);
+ } else if (ast->kind == AstNodeKind_logical_expr) {
+ codegen_logical_expr(g, ast);
+ } else if (ast->kind == AstNodeKind_assign_expr) {
+ codegen_assign_expr(g, ast);
+ } else if (ast->kind == AstNodeKind_func_call) {
+ codegen_func_call(g, ast);
+ } else if (ast->kind == AstNodeKind_lvar) {
+ codegen_lvar(g, ast, gen_mode);
+ } else if (ast->kind == AstNodeKind_gvar) {
+ codegen_gvar(g, ast, gen_mode);
+ } else {
+ unreachable();
+ }
+}
+
+void codegen_return_stmt(CodeGen* g, AstNode* ast) {
+ if (ast->node_expr) {
+ codegen_expr(g, ast->node_expr, GenMode_rval);
+ printf(" pop rax\n");
+ }
+ codegen_func_epilogue(g, ast);
+}
+
+void codegen_if_stmt(CodeGen* g, AstNode* ast) {
+ int label = codegen_new_label(g);
+
+ codegen_expr(g, ast->node_cond, GenMode_rval);
+ printf(" pop rax\n");
+ printf(" cmp rax, 0\n");
+ printf(" je .Lelse%d\n", label);
+ codegen_stmt(g, ast->node_then);
+ printf(" jmp .Lend%d\n", label);
+ printf(".Lelse%d:\n", label);
+ if (ast->node_else) {
+ codegen_stmt(g, ast->node_else);
+ }
+ printf(".Lend%d:\n", label);
+}
+
+void codegen_for_stmt(CodeGen* g, AstNode* ast) {
+ int label = codegen_new_label(g);
+ ++g->loop_labels;
+ *g->loop_labels = label;
+
+ if (ast->node_init) {
+ codegen_expr(g, ast->node_init, GenMode_rval);
+ printf(" pop rax\n");
+ }
+ printf(".Lbegin%d:\n", label);
+ codegen_expr(g, ast->node_cond, GenMode_rval);
+ printf(" pop rax\n");
+ printf(" cmp rax, 0\n");
+ printf(" je .Lend%d\n", label);
+ codegen_stmt(g, ast->node_body);
+ printf(".Lcontinue%d:\n", label);
+ if (ast->node_update) {
+ codegen_expr(g, ast->node_update, GenMode_rval);
+ printf(" pop rax\n");
+ }
+ printf(" jmp .Lbegin%d\n", label);
+ printf(".Lend%d:\n", label);
+
+ --g->loop_labels;
+}
+
+void codegen_do_while_stmt(CodeGen* g, AstNode* ast) {
+ int label = codegen_new_label(g);
+ ++g->loop_labels;
+ *g->loop_labels = label;
+
+ printf(".Lbegin%d:\n", label);
+ codegen_stmt(g, ast->node_body);
+ printf(".Lcontinue%d:\n", label);
+ codegen_expr(g, ast->node_cond, GenMode_rval);
+ printf(" pop rax\n");
+ printf(" cmp rax, 0\n");
+ printf(" je .Lend%d\n", label);
+ printf(" jmp .Lbegin%d\n", label);
+ printf(".Lend%d:\n", label);
+
+ --g->loop_labels;
+}
+
+void codegen_break_stmt(CodeGen* g, AstNode* ast) {
+ int label = *g->loop_labels;
+ printf(" jmp .Lend%d\n", label);
+}
+
+void codegen_continue_stmt(CodeGen* g, AstNode* ast) {
+ int label = *g->loop_labels;
+ printf(" jmp .Lcontinue%d\n", label);
+}
+
+void codegen_expr_stmt(CodeGen* g, AstNode* ast) {
+ codegen_expr(g, ast->node_expr, GenMode_rval);
+ printf(" pop rax\n");
+}
+
+void codegen_var_decl(CodeGen* g, AstNode* ast) {
+}
+
+void codegen_block_stmt(CodeGen* g, AstNode* ast) {
+ int i;
+ for (i = 0; i < ast->node_len; ++i) {
+ AstNode* stmt = ast->node_items + i;
+ codegen_stmt(g, stmt);
+ }
+}
+
+void codegen_stmt(CodeGen* g, AstNode* ast) {
+ if (ast->kind == AstNodeKind_list) {
+ codegen_block_stmt(g, ast);
+ } else if (ast->kind == AstNodeKind_return_stmt) {
+ codegen_return_stmt(g, ast);
+ } else if (ast->kind == AstNodeKind_if_stmt) {
+ codegen_if_stmt(g, ast);
+ } else if (ast->kind == AstNodeKind_for_stmt) {
+ codegen_for_stmt(g, ast);
+ } else if (ast->kind == AstNodeKind_do_while_stmt) {
+ codegen_do_while_stmt(g, ast);
+ } else if (ast->kind == AstNodeKind_break_stmt) {
+ codegen_break_stmt(g, ast);
+ } else if (ast->kind == AstNodeKind_continue_stmt) {
+ codegen_continue_stmt(g, ast);
+ } else if (ast->kind == AstNodeKind_expr_stmt) {
+ codegen_expr_stmt(g, ast);
+ } else if (ast->kind == AstNodeKind_lvar_decl) {
+ codegen_var_decl(g, ast);
+ } else {
+ unreachable();
+ }
+}
+
+void codegen_func(CodeGen* g, AstNode* ast) {
+ printf("%.*s:\n", ast->name.len, ast->name.data);
+
+ codegen_func_prologue(g, ast);
+ codegen_stmt(g, ast->node_body);
+ codegen_func_epilogue(g, ast);
+
+ printf("\n");
+}
+
+void codegen(Program* prog) {
+ CodeGen* g = codegen_new();
+
+ printf(".intel_syntax noprefix\n\n");
+
+ int i;
+ for (i = 0; prog->str_literals[i]; ++i) {
+ printf(".Lstr__%d:\n", i + 1);
+ printf(" .string \"%s\"\n\n", prog->str_literals[i]);
+ }
+
+ printf(".globl main\n\n");
+
+ for (i = 0; i < prog->funcs->node_len; ++i) {
+ AstNode* func = prog->funcs->node_items + i;
+ codegen_func(g, func);
+ }
+}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-12-01 06:28:16 +0000