diff options
Diffstat (limited to 'src/lua51/lvm.c')
| -rw-r--r-- | src/lua51/lvm.c | 54 |
1 files changed, 46 insertions, 8 deletions
diff --git a/src/lua51/lvm.c b/src/lua51/lvm.c index 85e214a..21de678 100644 --- a/src/lua51/lvm.c +++ b/src/lua51/lvm.c @@ -373,7 +373,7 @@ static void Arith (lua_State *L, StkId ra, const TValue *rb, } - +//c 虚拟机主入口 //c 执行lua函数（不含C函数，C函数在luaD_precall执行) //c 读取字节码并运行，沟通前端和后端的桥梁 //c 在ldo.c->luaD_call函数中执行，前一步是luaD_precall() @@ -390,7 +390,7 @@ void luaV_execute (lua_State *L, int nexeccalls) { pc = L->savedpc;//c 最开始是luaD_precall中赋值的函数原型的指令开头 cl = &clvalue(L->ci->func)->l; - base = L->base; + base = L->base; //c base是寄存器开始地址,每个方法被调用时都会得到自己的一组虚拟寄存器 k = cl->p->k; //c 当前函数原型的常量，所有函数调用都会用到的 /* main loop of interpreter */ @@ -407,7 +407,7 @@ void luaV_execute (lua_State *L, int nexeccalls) { base = L->base; } /* warning!! several calls may realloc the stack and invalidate `ra' */ - ra = RA(i); + ra = RA(i); //c 从指令中拿到ra lua_assert(base == L->base && L->base == L->ci->base); lua_assert(base <= L->top && L->top <= L->stack + L->stacksize); lua_assert(L->top == L->ci->top || luaG_checkopenop(i)); @@ -729,18 +729,56 @@ void luaV_execute (lua_State *L, int nexeccalls) { continue; } case OP_CLOSURE: { - Proto *p; + Proto *p; //c 函数原型首地址 Closure *ncl; int nup, j; - p = cl->p->p[GETARG_Bx(i)]; - nup = p->nups; + p = cl->p->p[GETARG_Bx(i)]; //c 根据索引得到函数原型地址 + //c lua的每个函数会记录这个函数的信息：参数个数、使用到的stack slot数目、upvalue数目、局部变量数目、常数表、局部函数 + nup = p->nups; //c number of upvalues， + //c 创建闭包new closure ncl = luaF_newLclosure(L, nup, cl->env); - ncl->l.p = p; + ncl->l.p = p; // 设置函数原型 + /* //c 一个闭包的创建如下 +----------------------------------- +1 local a = 10 +2 local b = 20 +3 +4 function foo () +5 return a + b +6 end +7 +8 local c = 30 +9 foo() +----------------------------------- +main <main.lua:0,0> (10 instructions, 40 bytes at 009512A8) +0+ params, 4 slots, 0 upvalues, 3 locals, 4 constants, 1 function + 1 [1] LOADK 0 -1 ; 10 + 2 [2] LOADK 1 -2 ; 20 + 3 [6] CLOSURE 2 0 ; 00951CC0 + 4 [6] MOVE 0 0 + 5 [6] MOVE 0 1 + 6 [4] SETGLOBAL 2 -3 ; foo + 7 [8] LOADK 2 -4 ; 30 + 8 [9] GETGLOBAL 3 -3 ; foo + 9 [9] CALL 3 1 1 + 10 [9] RETURN 0 1 + +function <main.lua:4,6> (5 instructions, 20 bytes at 00951CC0) +0 params, 2 slots, 2 upvalues, 0 locals, 0 constants, 0 functions + 1 [5] GETUPVAL 0 0 ; a + 2 [5] GETUPVAL 1 1 ; b + 3 [5] ADD 0 0 1 + 4 [5] RETURN 0 2 + 5 [6] RETURN 0 1 +----------------------------------- +012712A8的[6]是闭包的创建过程，两个MOVE指令用来设置闭包的upvalue，两个MOVE的第一个操作数无用 + */ + //c 设置闭包的upvalue值 for (j=0; j<nup; j++, pc++) { if (GET_OPCODE(*pc) == OP_GETUPVAL) ncl->l.upvals[j] = cl->upvals[GETARG_B(*pc)]; else { - lua_assert(GET_OPCODE(*pc) == OP_MOVE); + lua_assert(GET_OPCODE(*pc) == OP_MOVE); ncl->l.upvals[j] = luaF_findupval(L, base + GETARG_B(*pc)); } } |