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import "compiler/ast.cup"
import "std/file.cup"
let gen_out_file: File*;
fn emit_asm4(msg1: char*, msg2: char*, msg3: char*, msg4: char*) {
fwrite(gen_out_file, msg1, strlen(msg1));
fwrite(gen_out_file, msg2, strlen(msg2));
fwrite(gen_out_file, msg3, strlen(msg3));
fwrite(gen_out_file, msg4, strlen(msg4));
}
fn emit_asm3(msg1: char*, msg2: char*, msg3: char*) {
fwrite(gen_out_file, msg1, strlen(msg1));
fwrite(gen_out_file, msg2, strlen(msg2));
fwrite(gen_out_file, msg3, strlen(msg3));
}
fn emit_asm2(msg1: char*, msg2: char*) {
fwrite(gen_out_file, msg1, strlen(msg1));
fwrite(gen_out_file, msg2, strlen(msg2));
}
fn emit_asm(msg: char*) {
fwrite(gen_out_file, msg, strlen(msg));
}
fn emit_num(num: int) {
fputu(gen_out_file, num);
}
fn generate_syscall(num: int) {
emit_asm(" mov rax, "); emit_num(num); emit_asm("\n");
emit_asm(" syscall\n");
}
fn generate_lvalue_into_rax(node: Node*) {
if (node.typ == AST_LOCAL_VAR) {
let offset = node.d.variable.offset;
emit_asm(" mov rax, rbp\n");
emit_asm(" sub rax, "); emit_num(offset); emit_asm("\n");
} else {
die2("Unsupported type in generate_lvalue_into_rax: ", node_type_to_string(node.typ));
}
}
fn generate_expr_into_rax(node: Node*) {
if (node.typ == AST_LITERAL) {
if (node.etyp.typ == TYPE_INT) {
emit_asm(" mov rax, "); emit_num(node.d.literal.as_int); emit_asm("\n");
} else {
die("Unsupported literal type in generate_expr_into_rax");
}
} else if (node.typ == AST_PLUS) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" add rax, rbx\n");
} else if (node.typ == AST_MINUS) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" sub rax, rbx\n");
} else if (node.typ == AST_DIV) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" cqo\n");
emit_asm(" idiv rbx\n");
} else if (node.typ == AST_MOD) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" cqo\n");
emit_asm(" idiv rbx\n");
emit_asm(" mov rax, rdx\n");
} else if (node.typ == AST_MUL) {
generate_expr_into_rax(node.d.binary.rhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.binary.lhs);
emit_asm(" pop rbx\n");
emit_asm(" imul rbx\n");
} else if (is_lvalue(node.typ)) {
generate_lvalue_into_rax(node);
emit_asm(" mov rax, [rax]\n");
} else if (node.typ == AST_ASSIGN) {
putsln("...");
generate_lvalue_into_rax(node.d.assign.lhs);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.assign.rhs);
emit_asm(" pop rbx\n");
emit_asm(" mov [rbx], rax\n");
} else {
die2("Unsupported node type in generate_expr_into_rax: ", node_type_to_string(node.typ));
}
}
fn generate_block(node: Node*);
fn generate_statement(node: Node*) {
if (node.typ == AST_RETURN) {
generate_expr_into_rax(node.d.unary);
emit_asm(" mov rsp, rbp\n");
emit_asm(" pop rbp\n");
emit_asm(" ret\n");
} else if (node.typ == AST_VARDECL) {
if (node.d.var_decl.init) {
generate_expr_into_rax(node.d.var_decl.init);
let offset = node.d.var_decl.var.offset;
emit_asm(" mov [rbp-"); emit_num(offset); emit_asm("], rax\n");
}
} else if (node.typ == AST_BLOCK) {
generate_block(node);
} else {
// Default to a simple expression statement
generate_expr_into_rax(node);
}
}
fn generate_block(node: Node*) {
let n = node.d.block.children.size;
for (let i = 0; i < n; ++i) {
generate_statement(node.d.block.children.data[i]);
}
}
fn generate_function(node: Node*) {
emit_asm3("global func_", node.d.func.name, "\n");
emit_asm3("func_", node.d.func.name, ":\n");
emit_asm(" push rbp\n");
emit_asm(" mov rbp, rsp\n");
emit_asm(" sub rsp, "); emit_num(node.d.func.max_locals_size); emit_asm("\n");
generate_block(node.d.func.body);
emit_asm(" mov rsp, rbp\n");
emit_asm(" pop rbp\n");
emit_asm(" ret\n");
}
fn generate_program(ast: Node*, file: File*) {
gen_out_file = file;
let n = ast.d.block.children.size;
for (let i = 0; i < n; ++i) {
let node: Node* = ast.d.block.children.data[i];
if (node.typ == AST_FUNC) {
generate_function(node);
} else {
die("Unknown node type in generate_program");
}
}
if (OS_IS_MACOS) {
emit_asm("global _main\n");
emit_asm("_main:\n");
// Push argv
emit_asm(" mov rax, rsi\n");
emit_asm(" push rax\n");
// Push argc
emit_asm(" mov rax, rdi\n");
emit_asm(" push rax\n");
} else {
emit_asm("global _start\n");
emit_asm("_start:\n");
emit_asm(" mov rbp, rsp\n");
// // Push argv
emit_asm(" mov rax, rbp\n");
emit_asm(" add rax, 8\n");
emit_asm(" push rax\n");
// Push argc
emit_asm(" mov rax, [rbp]\n");
emit_asm(" push rax\n");
}
emit_asm(" call func_main\n");
emit_asm(" mov rdi, rax\n");
generate_syscall(SYS_exit);
}
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