stage2 大量优化代码使其自举编译时间大幅缩短

stage2/ir2vm.spl

@@ -362,7 +362,7 @@ fn frame_build(fl: *FrameLayout, ctx: *Ir2Vm, fid: usize) {
     var i: usize = 0;
     while i < n {
         var blank: Slot = .{ .result_off = 0, .data_off = 0 };
-        match Vec.push(&fl.slots, &blank as *u8) { .Ok => {}, .Err(error) => {} }
+        ignore_bool(Vec.push_raw(&fl.slots, &blank as *u8));
         i = i + 1;
     }
 
@@ -421,7 +421,17 @@ fixups: *Vec,
 terminated: bool,
 
 fn emit(cg: *Cgen, op: Op, ty: VmKind, imm: usize) {
-    ignore_usize(Mcode.add_instr(&cg.ctx.prog, op, ty, imm));
+    var prog = &cg.ctx.prog;
+    var i = prog.insns.len;
+    if i < prog.insns.cap {
+        var p = (prog.insns.data as *VmIns) + i;
+        p.opcode = op;
+        p.ty = ty;
+        p.imm = imm;
+        prog.insns.len = i + 1;
+        ret;
+    }
+    ignore_usize(Mcode.add_instr(prog, op, ty, imm));
 }
 
 fn ip_of(cg: *Cgen): usize {