refactor: 拆分 statement emit 分发逻辑

2026-06-23 18:17:31 +08:00
parent e736794ba3
commit 62ff06a6f2
9 changed files with 654 additions and 530 deletions
@@ -0,0 +1,49 @@
+use super::*;
+
+impl Compiler {
+    pub(in crate::emitter) fn emit_if_statement(
+        &self, stmt: &Statement, ctx: &mut CompileCtx,
+    ) -> Result<Option<u8>, String> {
+        let Statement::IfStatement(ifs) = stmt else {
+            return Ok(None);
+        };
+        let id = ctx.next_label_id();
+        let else_label = Label::IfElse(id);
+        let end_label = Label::IfEnd(id);
+
+        let test_reg = self.emit_expression(&ifs.test, ctx)?;
+
+        let else_pos = ctx.resolve_label(else_label)?;
+        let offset = (else_pos as isize) - (ctx.bytecode.len() as isize);
+        let offset = ctx.checked_jump_offset(offset);
+        ctx.emit(opcode::encode_jmp_if_false(test_reg, offset));
+
+        let cons_reg = self.emit_statement(&ifs.consequent, ctx)?;
+        let result_reg = ctx.alloc_reg();
+        if let Some(r) = cons_reg {
+            ctx.emit(opcode::encode(OpCode::LOAD_VAR, result_reg, r, 0));
+        } else {
+            let undef_idx = ctx.add_constant(Constant::Undefined);
+            ctx.emit_load_const(result_reg, undef_idx);
+        }
+
+        if ifs.alternate.is_some() {
+            let end_pos = ctx.resolve_label(end_label)?;
+            let offset = (end_pos as isize) - (ctx.bytecode.len() as isize);
+            let offset = ctx.checked_jump_offset(offset);
+            ctx.emit(opcode::encode_jmp(offset));
+        }
+
+        if let Some(alt) = &ifs.alternate {
+            let alt_reg = self.emit_statement(alt, ctx)?;
+            if let Some(r) = alt_reg {
+                ctx.emit(opcode::encode(OpCode::LOAD_VAR, result_reg, r, 0));
+            } else {
+                let undef_idx = ctx.add_constant(Constant::Undefined);
+                ctx.emit_load_const(result_reg, undef_idx);
+            }
+        }
+
+        Ok(Some(result_reg))
+    }
+}