1 /* $NetBSD: lparser.h,v 1.9 2023/04/16 20:46:17 nikita Exp $ */ 2 3 /* 4 ** Id: lparser.h 5 ** Lua Parser 6 ** See Copyright Notice in lua.h 7 */ 8 9 #ifndef lparser_h 10 #define lparser_h 11 12 #include "llimits.h" 13 #include "lobject.h" 14 #include "lzio.h" 15 16 17 /* 18 ** Expression and variable descriptor. 19 ** Code generation for variables and expressions can be delayed to allow 20 ** optimizations; An 'expdesc' structure describes a potentially-delayed 21 ** variable/expression. It has a description of its "main" value plus a 22 ** list of conditional jumps that can also produce its value (generated 23 ** by short-circuit operators 'and'/'or'). 24 */ 25 26 /* kinds of variables/expressions */ 27 typedef enum { 28 VVOID, /* when 'expdesc' describes the last expression of a list, 29 this kind means an empty list (so, no expression) */ 30 VNIL, /* constant nil */ 31 VTRUE, /* constant true */ 32 VFALSE, /* constant false */ 33 VK, /* constant in 'k'; info = index of constant in 'k' */ 34 #ifndef _KERNEL 35 VKFLT, /* floating constant; nval = numerical float value */ 36 #endif 37 VKINT, /* integer constant; ival = numerical integer value */ 38 VKSTR, /* string constant; strval = TString address; 39 (string is fixed by the lexer) */ 40 VNONRELOC, /* expression has its value in a fixed register; 41 info = result register */ 42 VLOCAL, /* local variable; var.ridx = register index; 43 var.vidx = relative index in 'actvar.arr' */ 44 VUPVAL, /* upvalue variable; info = index of upvalue in 'upvalues' */ 45 VCONST, /* compile-time <const> variable; 46 info = absolute index in 'actvar.arr' */ 47 VINDEXED, /* indexed variable; 48 ind.t = table register; 49 ind.idx = key's R index */ 50 VINDEXUP, /* indexed upvalue; 51 ind.t = table upvalue; 52 ind.idx = key's K index */ 53 VINDEXI, /* indexed variable with constant integer; 54 ind.t = table register; 55 ind.idx = key's value */ 56 VINDEXSTR, /* indexed variable with literal string; 57 ind.t = table register; 58 ind.idx = key's K index */ 59 VJMP, /* expression is a test/comparison; 60 info = pc of corresponding jump instruction */ 61 VRELOC, /* expression can put result in any register; 62 info = instruction pc */ 63 VCALL, /* expression is a function call; info = instruction pc */ 64 VVARARG /* vararg expression; info = instruction pc */ 65 } expkind; 66 67 68 #define vkisvar(k) (VLOCAL <= (k) && (k) <= VINDEXSTR) 69 #define vkisindexed(k) (VINDEXED <= (k) && (k) <= VINDEXSTR) 70 71 72 typedef struct expdesc { 73 expkind k; 74 union { 75 lua_Integer ival; /* for VKINT */ 76 lua_Number nval; /* for VKFLT */ 77 TString *strval; /* for VKSTR */ 78 int info; /* for generic use */ 79 struct { /* for indexed variables */ 80 short idx; /* index (R or "long" K) */ 81 lu_byte t; /* table (register or upvalue) */ 82 } ind; 83 struct { /* for local variables */ 84 lu_byte ridx; /* register holding the variable */ 85 unsigned short vidx; /* compiler index (in 'actvar.arr') */ 86 } var; 87 } u; 88 int t; /* patch list of 'exit when true' */ 89 int f; /* patch list of 'exit when false' */ 90 } expdesc; 91 92 93 /* kinds of variables */ 94 #define VDKREG 0 /* regular */ 95 #define RDKCONST 1 /* constant */ 96 #define RDKTOCLOSE 2 /* to-be-closed */ 97 #define RDKCTC 3 /* compile-time constant */ 98 99 /* description of an active local variable */ 100 typedef union Vardesc { 101 struct { 102 TValuefields; /* constant value (if it is a compile-time constant) */ 103 lu_byte kind; 104 lu_byte ridx; /* register holding the variable */ 105 short pidx; /* index of the variable in the Proto's 'locvars' array */ 106 TString *name; /* variable name */ 107 } vd; 108 TValue k; /* constant value (if any) */ 109 } Vardesc; 110 111 112 113 /* description of pending goto statements and label statements */ 114 typedef struct Labeldesc { 115 TString *name; /* label identifier */ 116 int pc; /* position in code */ 117 int line; /* line where it appeared */ 118 lu_byte nactvar; /* number of active variables in that position */ 119 lu_byte close; /* goto that escapes upvalues */ 120 } Labeldesc; 121 122 123 /* list of labels or gotos */ 124 typedef struct Labellist { 125 Labeldesc *arr; /* array */ 126 int n; /* number of entries in use */ 127 int size; /* array size */ 128 } Labellist; 129 130 131 /* dynamic structures used by the parser */ 132 typedef struct Dyndata { 133 struct { /* list of all active local variables */ 134 Vardesc *arr; 135 int n; 136 int size; 137 } actvar; 138 Labellist gt; /* list of pending gotos */ 139 Labellist label; /* list of active labels */ 140 } Dyndata; 141 142 143 /* control of blocks */ 144 struct BlockCnt; /* defined in lparser.c */ 145 146 147 /* state needed to generate code for a given function */ 148 typedef struct FuncState { 149 Proto *f; /* current function header */ 150 struct FuncState *prev; /* enclosing function */ 151 struct LexState *ls; /* lexical state */ 152 struct BlockCnt *bl; /* chain of current blocks */ 153 int pc; /* next position to code (equivalent to 'ncode') */ 154 int lasttarget; /* 'label' of last 'jump label' */ 155 int previousline; /* last line that was saved in 'lineinfo' */ 156 int nk; /* number of elements in 'k' */ 157 int np; /* number of elements in 'p' */ 158 int nabslineinfo; /* number of elements in 'abslineinfo' */ 159 int firstlocal; /* index of first local var (in Dyndata array) */ 160 int firstlabel; /* index of first label (in 'dyd->label->arr') */ 161 short ndebugvars; /* number of elements in 'f->locvars' */ 162 lu_byte nactvar; /* number of active local variables */ 163 lu_byte nups; /* number of upvalues */ 164 lu_byte freereg; /* first free register */ 165 lu_byte iwthabs; /* instructions issued since last absolute line info */ 166 lu_byte needclose; /* function needs to close upvalues when returning */ 167 } FuncState; 168 169 170 LUAI_FUNC int luaY_nvarstack (FuncState *fs); 171 LUAI_FUNC LClosure *luaY_parser (lua_State *L, ZIO *z, Mbuffer *buff, 172 Dyndata *dyd, const char *name, int firstchar); 173 174 175 #endif 176
Indexes created Fri Jun 12 00:25:51 UTC 2026