1 /* 2 ** $Id: lparser.h,v 1.76.1.1 2017/04/19 17:20:42 roberto Exp $ 3 ** Lua Parser 4 ** See Copyright Notice in lua.h 5 */ 6 7 #ifndef lparser_h 8 #define lparser_h 9 10 #include "llimits.h" 11 #include "lobject.h" 12 #include "lzio.h" 13 14 15 /* 16 ** Expression and variable descriptor. 17 ** Code generation for variables and expressions can be delayed to allow 18 ** optimizations; An 'expdesc' structure describes a potentially-delayed 19 ** variable/expression. It has a description of its "main" value plus a 20 ** list of conditional jumps that can also produce its value (generated 21 ** by short-circuit operators 'and'/'or'). 22 */ 23 24 /* kinds of variables/expressions */ 25 typedef enum { 26 VVOID, /* when 'expdesc' describes the last expression a list, 27 this kind means an empty list (so, no expression) */ 28 VNIL, /* constant nil */ 29 VTRUE, /* constant true */ 30 VFALSE, /* constant false */ 31 VK, /* constant in 'k'; info = index of constant in 'k' */ 32 VKFLT, /* floating constant; nval = numerical float value */ 33 VKINT, /* integer constant; nval = numerical integer value */ 34 VNONRELOC, /* expression has its value in a fixed register; 35 info = result register */ 36 VLOCAL, /* local variable; info = local register */ 37 VUPVAL, /* upvalue variable; info = index of upvalue in 'upvalues' */ 38 VINDEXED, /* indexed variable; 39 ind.vt = whether 't' is register or upvalue; 40 ind.t = table register or upvalue; 41 ind.idx = key's R/K index */ 42 VJMP, /* expression is a test/comparison; 43 info = pc of corresponding jump instruction */ 44 VRELOCABLE, /* expression can put result in any register; 45 info = instruction pc */ 46 VCALL, /* expression is a function call; info = instruction pc */ 47 VVARARG /* vararg expression; info = instruction pc */ 48 } expkind; 49 50 51 #define vkisvar(k) (VLOCAL <= (k) && (k) <= VINDEXED) 52 #define vkisinreg(k) ((k) == VNONRELOC || (k) == VLOCAL) 53 54 typedef struct expdesc { 55 expkind k; 56 union { 57 lua_Integer ival; /* for VKINT */ 58 lua_Number nval; /* for VKFLT */ 59 int info; /* for generic use */ 60 struct { /* for indexed variables (VINDEXED) */ 61 short idx; /* index (R/K) */ 62 lu_byte t; /* table (register or upvalue) */ 63 lu_byte vt; /* whether 't' is register (VLOCAL) or upvalue (VUPVAL) */ 64 } ind; 65 } u; 66 int t; /* patch list of 'exit when true' */ 67 int f; /* patch list of 'exit when false' */ 68 } expdesc; 69 70 71 /* description of active local variable */ 72 typedef struct Vardesc { 73 short idx; /* variable index in stack */ 74 } Vardesc; 75 76 77 /* description of pending goto statements and label statements */ 78 typedef struct Labeldesc { 79 TString *name; /* label identifier */ 80 int pc; /* position in code */ 81 int line; /* line where it appeared */ 82 lu_byte nactvar; /* local level where it appears in current block */ 83 } Labeldesc; 84 85 86 /* list of labels or gotos */ 87 typedef struct Labellist { 88 Labeldesc *arr; /* array */ 89 int n; /* number of entries in use */ 90 int size; /* array size */ 91 } Labellist; 92 93 94 /* dynamic structures used by the parser */ 95 typedef struct Dyndata { 96 struct { /* list of active local variables */ 97 Vardesc *arr; 98 int n; 99 int size; 100 } actvar; 101 Labellist gt; /* list of pending gotos */ 102 Labellist label; /* list of active labels */ 103 } Dyndata; 104 105 106 /* control of blocks */ 107 struct BlockCnt; /* defined in lparser.c */ 108 109 110 /* state needed to generate code for a given function */ 111 typedef struct FuncState { 112 Proto *f; /* current function header */ 113 struct FuncState *prev; /* enclosing function */ 114 struct LexState *ls; /* lexical state */ 115 struct BlockCnt *bl; /* chain of current blocks */ 116 int pc; /* next position to code (equivalent to 'ncode') */ 117 int lasttarget; /* 'label' of last 'jump label' */ 118 int jpc; /* list of pending jumps to 'pc' */ 119 int nk; /* number of elements in 'k' */ 120 int np; /* number of elements in 'p' */ 121 int firstlocal; /* index of first local var (in Dyndata array) */ 122 short nlocvars; /* number of elements in 'f->locvars' */ 123 lu_byte nactvar; /* number of active local variables */ 124 lu_byte nups; /* number of upvalues */ 125 lu_byte freereg; /* first free register */ 126 } FuncState; 127 128 129 LUAI_FUNC LClosure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, 130 Dyndata *dyd, const char *name, int firstchar); 131 132 133 #endif 134