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-rw-r--r--compiler/codegen.cup124
1 files changed, 89 insertions, 35 deletions
diff --git a/compiler/codegen.cup b/compiler/codegen.cup
index 3d52397..c18500f 100644
--- a/compiler/codegen.cup
+++ b/compiler/codegen.cup
@@ -3,7 +3,7 @@ import "compiler/ast.cup"
import "std/file.cup"
let gen_out_file: File*;
-let gen_label_counter = 0;
+let gen_label_counter = -1; // So the labels start at 0
let gen_string_literals = vector_new();
@@ -49,6 +49,24 @@ fn generate_syscall(num: int) {
emit_asm(" syscall\n");
}
+fn subregister_for_type(typ: Type*): char* {
+ let n = size_for_type(typ);
+ if (n == 1) return "al";
+ if (n == 2) return "ax";
+ if (n == 4) return "eax";
+ if (n == 8) return "rax";
+ die2(here, "Unsupported type size");
+}
+
+fn specifier_for_type(typ: Type*): char* {
+ let n = size_for_type(typ);
+ if (n == 1) return "byte";
+ if (n == 2) return "word";
+ if (n == 4) return "dword";
+ if (n == 8) return "qword";
+ die2(here, "Unsupported type size");
+}
+
fn generate_expr_into_rax(node: Node*);
fn generate_lvalue_into_rax(node: Node*) {
@@ -60,6 +78,13 @@ fn generate_lvalue_into_rax(node: Node*) {
let offset = node.d.variable.offset;
emit_asm(" mov rax, global_vars\n");
emit_asm(" add rax, "); emit_num(offset); emit_asm("\n");
+ } else if (node.typ == AST_MEMBER) {
+ let offset = node.d.member.offset;
+ if (node.d.member.is_ptr)
+ generate_expr_into_rax(node.d.member.obj);
+ else
+ generate_lvalue_into_rax(node.d.member.obj);
+ emit_asm(" add rax, "); emit_num(offset); emit_asm("\n");
} else if (node.typ == AST_DEREF) {
generate_expr_into_rax(node.d.unary);
} else {
@@ -102,12 +127,12 @@ fn generate_expr_into_rax(node: Node*) {
let label = ++gen_label_counter;
generate_expr_into_rax(node.d.conditional.cond);
emit_asm(" cmp rax, 0\n");
- emit_asm(" je .cond_els"); emit_num(label); emit_asm("\n");
+ emit_asm(" je .cond_else_"); emit_num(label); emit_asm("\n");
generate_expr_into_rax(node.d.conditional.then);
- emit_asm(" jmp .cond"); emit_num(label); emit_asm("\n");
- emit_asm(".cond_els"); emit_num(label); emit_asm(":\n");
+ emit_asm(" jmp .cond_end_"); emit_num(label); emit_asm("\n");
+ emit_asm(".cond_else_"); emit_num(label); emit_asm(":\n");
generate_expr_into_rax(node.d.conditional.els);
- emit_asm(".cond"); emit_num(label); emit_asm(":\n");
+ emit_asm(".cond_end_"); emit_num(label); emit_asm(":\n");
} else if (node.typ == AST_PLUS) {
generate_expr_into_rax(node.d.binary.rhs);
@@ -242,41 +267,46 @@ fn generate_expr_into_rax(node: Node*) {
generate_expr_into_rax(node.d.binary.lhs,);
// If left is true, we can short-circuit
emit_asm(" cmp rax, 0\n");
- emit_asm(" je .or_r"); emit_num(label); emit_asm("\n");
+ emit_asm(" je .or_right_"); emit_num(label); emit_asm("\n");
emit_asm(" mov rax, 1\n");
- emit_asm(" jmp .or_e"); emit_num(label); emit_asm("\n");
- emit_asm(".or_r"); emit_num(label); emit_asm(":\n");
+ emit_asm(" jmp .or_end_"); emit_num(label); emit_asm("\n");
+ emit_asm(".or_right_"); emit_num(label); emit_asm(":\n");
generate_expr_into_rax(node.d.binary.rhs);
// Booleanize the result
emit_asm(" cmp rax, 0\n");
emit_asm(" setne al\n");
- emit_asm(".or_e"); emit_num(label); emit_asm(":\n");
+ emit_asm(".or_end_"); emit_num(label); emit_asm(":\n");
} else if (node.typ == AST_AND) {
let label = ++gen_label_counter;
generate_expr_into_rax(node.d.binary.lhs);
// If left is false, we can short-circuit
emit_asm(" cmp rax, 0\n");
- emit_asm(" jne .and_r"); emit_num(label); emit_asm("\n");
+ emit_asm(" jne .and_right_"); emit_num(label); emit_asm("\n");
emit_asm(" mov rax, 0\n");
- emit_asm(" jmp .and_e"); emit_num(label); emit_asm("\n");
- emit_asm(".and_r"); emit_num(label); emit_asm(":\n");
+ emit_asm(" jmp .and_end_"); emit_num(label); emit_asm("\n");
+ emit_asm(".and_right_"); emit_num(label); emit_asm(":\n");
generate_expr_into_rax(node.d.binary.rhs);
// Booleanize the result
emit_asm(" cmp rax, 0\n");
emit_asm(" setne al\n");
- emit_asm(".and_e"); emit_num(label); emit_asm(":\n");
+ emit_asm(".and_end_"); emit_num(label); emit_asm(":\n");
} else if (is_lvalue(node.typ)) {
generate_lvalue_into_rax(node);
- emit_asm(" mov rax, [rax]\n");
+ if (size_for_type(node.etyp) == 8) {
+ emit_asm(" mov rax, [rax]\n");
+ } else {
+ emit_asm3(" movsx rax, ", specifier_for_type(node.etyp), " [rax]\n");
+ }
} else if (node.typ == AST_ASSIGN) {
- generate_lvalue_into_rax(node.d.assign.lhs);
+ let var = node.d.assign.lhs;
+ generate_lvalue_into_rax(var);
emit_asm(" push rax\n");
generate_expr_into_rax(node.d.assign.rhs);
emit_asm(" pop rbx\n");
- emit_asm(" mov [rbx], rax\n");
+ emit_asm3(" mov [rbx], ", subregister_for_type(var.etyp), "\n");
} else if (node.typ == AST_FUNCCALL) {
generate_function_call(node);
@@ -290,7 +320,16 @@ fn generate_block(node: Node*);
fn generate_statement(node: Node*) {
if (node.typ == AST_RETURN) {
- generate_expr_into_rax(node.d.unary);
+ if (node.d.unary) {
+ generate_expr_into_rax(node.d.unary);
+ } else {
+ emit_asm(" xor rax, rax\n"); // Default to 0
+ }
+
+ emit_asm(" push rax\n");
+ // TODO: Undo the defer stack here, this is for consistency with the C implementation for now.
+ emit_asm(" pop rax\n");
+
emit_asm(" mov rsp, rbp\n");
emit_asm(" pop rbp\n");
emit_asm(" ret\n");
@@ -305,40 +344,48 @@ fn generate_statement(node: Node*) {
} else if (node.typ == AST_IF) {
let label = ++gen_label_counter;
generate_expr_into_rax(node.d.conditional.cond);
- emit_asm(" cmp rax, 0\n");
- emit_asm(" je .els"); emit_num(label); emit_asm("\n");
- generate_statement(node.d.conditional.then);
- emit_asm(" jmp .if"); emit_num(label); emit_asm("\n");
- emit_asm(".els"); emit_num(label); emit_asm(":\n");
- if (node.d.conditional.els)
+ // If we don't have an `else` clause, we can simplify
+ if (node.d.conditional.els == null) {
+ emit_asm(" cmp rax, 0\n");
+ emit_asm(" je .if_end_"); emit_num(label); emit_asm("\n");
+ generate_statement(node.d.conditional.then);
+ emit_asm(".if_end_"); emit_num(label); emit_asm(":\n");
+ } else {
+ emit_asm(" cmp rax, 0\n");
+ emit_asm(" je .if_else_"); emit_num(label); emit_asm("\n");
+ generate_statement(node.d.conditional.then);
+ emit_asm(" jmp .if_end_"); emit_num(label); emit_asm("\n");
+ emit_asm(".if_else_"); emit_num(label); emit_asm(":\n");
generate_statement(node.d.conditional.els);
- emit_asm(".if"); emit_num(label); emit_asm(":\n");
-
+ emit_asm(".if_end_"); emit_num(label); emit_asm(":\n");
+ }
} else if (node.typ == AST_WHILE) {
let label = ++gen_label_counter;
- emit_asm(".loop_s"); emit_num(label); emit_asm(":\n");
+ emit_asm(".loop_start_"); emit_num(label); emit_asm(":\n");
+ emit_asm(".loop_continue_"); emit_num(label); emit_asm(":\n");
generate_expr_into_rax(node.d.looop.cond);
emit_asm(" cmp rax, 0\n");
- emit_asm(" je .loop_e"); emit_num(label); emit_asm("\n");
+ emit_asm(" je .loop_end_"); emit_num(label); emit_asm("\n");
generate_statement(node.d.looop.body);
- emit_asm(" jmp .loop_s"); emit_num(label); emit_asm("\n");
- emit_asm(".loop_e"); emit_num(label); emit_asm(":\n");
+ emit_asm(" jmp .loop_start_"); emit_num(label); emit_asm("\n");
+ emit_asm(".loop_end_"); emit_num(label); emit_asm(":\n");
} else if (node.typ == AST_FOR) {
let label = ++gen_label_counter;
if (node.d.looop.init)
generate_statement(node.d.looop.init);
- emit_asm(".loop_s"); emit_num(label); emit_asm(":\n");
+ emit_asm(".loop_start_"); emit_num(label); emit_asm(":\n");
if (node.d.looop.cond) {
generate_expr_into_rax(node.d.looop.cond);
emit_asm(" cmp rax, 0\n");
- emit_asm(" je .loop_e"); emit_num(label); emit_asm("\n");
+ emit_asm(" je .loop_end_"); emit_num(label); emit_asm("\n");
}
generate_statement(node.d.looop.body);
+ emit_asm(".loop_continue_"); emit_num(label); emit_asm(":\n");
if (node.d.looop.step)
generate_statement(node.d.looop.step);
- emit_asm(" jmp .loop_s"); emit_num(label); emit_asm("\n");
- emit_asm(".loop_e"); emit_num(label); emit_asm(":\n");
+ emit_asm(" jmp .loop_start_"); emit_num(label); emit_asm("\n");
+ emit_asm(".loop_end_"); emit_num(label); emit_asm(":\n");
} else {
// Default to a simple expression statement
@@ -354,6 +401,10 @@ fn generate_block(node: Node*) {
}
fn generate_function(node: Node*) {
+ // Skip declarations
+ if (node.d.func.body == null)
+ return;
+
emit_asm3("global func_", node.d.func.name, "\n");
emit_asm3("func_", node.d.func.name, ":\n");
emit_asm(" push rbp\n");
@@ -364,6 +415,8 @@ fn generate_function(node: Node*) {
emit_asm(" mov rsp, rbp\n");
emit_asm(" pop rbp\n");
+ // Return 0 by default if we don't have a return statement
+ emit_asm(" mov qword rax, 0\n");
emit_asm(" ret\n");
}
@@ -409,11 +462,12 @@ fn generate_program(ast: Node*, file: File*) {
for (let i = 0; i < n; ++i) {
let node: Node* = ast.d.block.children.data[i];
if (node.typ == AST_VARDECL && node.d.var_decl.init) {
+ let expr = 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 rbx, global_vars\n");
emit_asm(" add rbx, "); emit_num(offset); emit_asm("\n");
- emit_asm(" mov [rbx], rax\n");
+ emit_asm3(" mov [rbx], ", subregister_for_type(expr.etyp), "\n");
}
}
@@ -436,6 +490,6 @@ fn generate_program(ast: Node*, file: File*) {
emit_asm_char('`');
emit_asm(gen_string_literals.data[i]);
emit_asm_char('`');
- emit_asm("\n");
+ emit_asm(", 0\n");
}
} \ No newline at end of file
generated by cgit v1.2.3 (git 2.25.1) at 2026-03-11 04:23:44 +0000