lparser.h 5.8 KB

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