gdb/parser-defs.h

   1 /* Parser definitions for GDB.
   2
   3    Copyright (C) 1986-2021 Free Software Foundation, Inc.
   4
   5    Modified from expread.y by the Department of Computer Science at the
   6    State University of New York at Buffalo.
   7
   8    This file is part of GDB.
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  22
  23 #if !defined (PARSER_DEFS_H)
  24 #define PARSER_DEFS_H 1
  25
  26 #include "expression.h"
  27 #include "symtab.h"
  28
  29 struct block;
  30 struct language_defn;
  31 struct internalvar;
  32 class innermost_block_tracker;
  33
  34 extern bool parser_debug;
  35
  36 /* A class that can be used to build a "struct expression".  */
  37
  38 struct expr_builder
  39 {
  40   /* Constructor.  LANG is the language used to parse the expression.
  41      And GDBARCH is the gdbarch to use during parsing.  */
  42
  43   expr_builder (const struct language_defn *lang,
  44                 struct gdbarch *gdbarch);
  45
  46   DISABLE_COPY_AND_ASSIGN (expr_builder);
  47
  48   /* Resize the allocated expression to the correct size, and return
  49      it as an expression_up -- passing ownership to the caller.  */
  50   ATTRIBUTE_UNUSED_RESULT expression_up release ();
  51
  52   /* Return the gdbarch that was passed to the constructor.  */
  53
  54   struct gdbarch *gdbarch ()
  55   {
  56     return expout->gdbarch;
  57   }
  58
  59   /* Return the language that was passed to the constructor.  */
  60
  61   const struct language_defn *language ()
  62   {
  63     return expout->language_defn;
  64   }
  65
  66   /* The size of the expression above.  */
  67
  68   size_t expout_size;
  69
  70   /* The expression related to this parser state.  */
  71
  72   expression_up expout;
  73
  74   /* The number of elements already in the expression.  This is used
  75      to know where to put new elements.  */
  76
  77   size_t expout_ptr;
  78 };
  79
  80 /* This is used for expression completion.  */
  81
  82 struct expr_completion_state
  83 {
  84   /* The index of the last struct expression directly before a '.' or
  85      '->'.  This is set when parsing and is only used when completing a
  86      field name.  It is -1 if no dereference operation was found.  */
  87   int expout_last_struct = -1;
  88
  89   /* If we are completing a tagged type name, this will be nonzero.  */
  90   enum type_code expout_tag_completion_type = TYPE_CODE_UNDEF;
  91
  92   /* The token for tagged type name completion.  */
  93   gdb::unique_xmalloc_ptr<char> expout_completion_name;
  94 };
  95
  96 /* An instance of this type is instantiated during expression parsing,
  97    and passed to the appropriate parser.  It holds both inputs to the
  98    parser, and result.  */
  99
 100 struct parser_state : public expr_builder
 101 {
 102   /* Constructor.  LANG is the language used to parse the expression.
 103      And GDBARCH is the gdbarch to use during parsing.  */
 104
 105   parser_state (const struct language_defn *lang,
 106                 struct gdbarch *gdbarch,
 107                 const struct block *context_block,
 108                 CORE_ADDR context_pc,
 109                 int comma,
 110                 const char *input,
 111                 int completion,
 112                 innermost_block_tracker *tracker,
 113                 bool void_p)
 114     : expr_builder (lang, gdbarch),
 115       expression_context_block (context_block),
 116       expression_context_pc (context_pc),
 117       comma_terminates (comma),
 118       lexptr (input),
 119       parse_completion (completion),
 120       block_tracker (tracker),
 121       void_context_p (void_p)
 122   {
 123   }
 124
 125   DISABLE_COPY_AND_ASSIGN (parser_state);
 126
 127   /* Begin counting arguments for a function call,
 128      saving the data about any containing call.  */
 129
 130   void start_arglist ()
 131   {
 132     m_funcall_chain.push_back (arglist_len);
 133     arglist_len = 0;
 134   }
 135
 136   /* Return the number of arguments in a function call just terminated,
 137      and restore the data for the containing function call.  */
 138
 139   int end_arglist ()
 140   {
 141     int val = arglist_len;
 142     arglist_len = m_funcall_chain.back ();
 143     m_funcall_chain.pop_back ();
 144     return val;
 145   }
 146
 147   /* Mark the current index as the starting location of a structure
 148      expression.  This is used when completing on field names.  */
 149
 150   void mark_struct_expression ();
 151
 152   /* Indicate that the current parser invocation is completing a tag.
 153      TAG is the type code of the tag, and PTR and LENGTH represent the
 154      start of the tag name.  */
 155
 156   void mark_completion_tag (enum type_code tag, const char *ptr, int length);
 157
 158
 159   /* If this is nonzero, this block is used as the lexical context for
 160      symbol names.  */
 161
 162   const struct block * const expression_context_block;
 163
 164   /* If expression_context_block is non-zero, then this is the PC
 165      within the block that we want to evaluate expressions at.  When
 166      debugging C or C++ code, we use this to find the exact line we're
 167      at, and then look up the macro definitions active at that
 168      point.  */
 169   const CORE_ADDR expression_context_pc;
 170
 171   /* Nonzero means stop parsing on first comma (if not within parentheses).  */
 172
 173   int comma_terminates;
 174
 175   /* During parsing of a C expression, the pointer to the next character
 176      is in this variable.  */
 177
 178   const char *lexptr;
 179
 180   /* After a token has been recognized, this variable points to it.
 181      Currently used only for error reporting.  */
 182   const char *prev_lexptr = nullptr;
 183
 184   /* Number of arguments seen so far in innermost function call.  */
 185
 186   int arglist_len = 0;
 187
 188   /* True if parsing an expression to attempt completion.  */
 189   int parse_completion;
 190
 191   /* Completion state is updated here.  */
 192   expr_completion_state m_completion_state;
 193
 194   /* The innermost block tracker.  */
 195   innermost_block_tracker *block_tracker;
 196
 197   /* True if no value is expected from the expression.  */
 198   bool void_context_p;
 199
 200 private:
 201
 202   /* Data structure for saving values of arglist_len for function calls whose
 203      arguments contain other function calls.  */
 204
 205   std::vector<int> m_funcall_chain;
 206 };
 207
 208 /* When parsing expressions we track the innermost block that was
 209    referenced.  */
 210
 211 class innermost_block_tracker
 212 {
 213 public:
 214   innermost_block_tracker (innermost_block_tracker_types types
 215                            = INNERMOST_BLOCK_FOR_SYMBOLS)
 216     : m_types (types),
 217       m_innermost_block (NULL)
 218   { /* Nothing.  */ }
 219
 220   /* Update the stored innermost block if the new block B is more inner
 221      than the currently stored block, or if no block is stored yet.  The
 222      type T tells us whether the block B was for a symbol or for a
 223      register.  The stored innermost block is only updated if the type T is
 224      a type we are interested in, the types we are interested in are held
 225      in M_TYPES and set during RESET.  */
 226   void update (const struct block *b, innermost_block_tracker_types t);
 227
 228   /* Overload of main UPDATE method which extracts the block from BS.  */
 229   void update (const struct block_symbol &bs)
 230   {
 231     update (bs.block, INNERMOST_BLOCK_FOR_SYMBOLS);
 232   }
 233
 234   /* Return the stored innermost block.  Can be nullptr if no symbols or
 235      registers were found during an expression parse, and so no innermost
 236      block was defined.  */
 237   const struct block *block () const
 238   {
 239     return m_innermost_block;
 240   }
 241
 242 private:
 243   /* The type of innermost block being looked for.  */
 244   innermost_block_tracker_types m_types;
 245
 246   /* The currently stored innermost block found while parsing an
 247      expression.  */
 248   const struct block *m_innermost_block;
 249 };
 250
 251 /* A string token, either a char-string or bit-string.  Char-strings are
 252    used, for example, for the names of symbols.  */
 253
 254 struct stoken
 255   {
 256     /* Pointer to first byte of char-string or first bit of bit-string.  */
 257     const char *ptr;
 258     /* Length of string in bytes for char-string or bits for bit-string.  */
 259     int length;
 260   };
 261
 262 struct typed_stoken
 263   {
 264     /* A language-specific type field.  */
 265     int type;
 266     /* Pointer to first byte of char-string or first bit of bit-string.  */
 267     char *ptr;
 268     /* Length of string in bytes for char-string or bits for bit-string.  */
 269     int length;
 270   };
 271
 272 struct stoken_vector
 273   {
 274     int len;
 275     struct typed_stoken *tokens;
 276   };
 277
 278 struct ttype
 279   {
 280     struct stoken stoken;
 281     struct type *type;
 282   };
 283
 284 struct symtoken
 285   {
 286     struct stoken stoken;
 287     struct block_symbol sym;
 288     int is_a_field_of_this;
 289   };
 290
 291 struct objc_class_str
 292   {
 293     struct stoken stoken;
 294     struct type *type;
 295     int theclass;
 296   };
 297
 298 /* Reverse an expression from suffix form (in which it is constructed)
 299    to prefix form (in which we can conveniently print or execute it).
 300    Ordinarily this always returns -1.  However, if LAST_STRUCT
 301    is not -1 (i.e., we are trying to complete a field name), it will
 302    return the index of the subexpression which is the left-hand-side
 303    of the struct operation at LAST_STRUCT.  */
 304
 305 extern int prefixify_expression (struct expression *expr,
 306                                  int last_struct = -1);
 307
 308 extern void write_exp_elt_opcode (struct expr_builder *, enum exp_opcode);
 309
 310 extern void write_exp_elt_sym (struct expr_builder *, struct symbol *);
 311
 312 extern void write_exp_elt_longcst (struct expr_builder *, LONGEST);
 313
 314 extern void write_exp_elt_floatcst (struct expr_builder *, const gdb_byte *);
 315
 316 extern void write_exp_elt_type (struct expr_builder *, struct type *);
 317
 318 extern void write_exp_elt_intern (struct expr_builder *, struct internalvar *);
 319
 320 extern void write_exp_string (struct expr_builder *, struct stoken);
 321
 322 void write_exp_string_vector (struct expr_builder *, int type,
 323                               struct stoken_vector *vec);
 324
 325 extern void write_exp_bitstring (struct expr_builder *, struct stoken);
 326
 327 extern void write_exp_elt_block (struct expr_builder *, const struct block *);
 328
 329 extern void write_exp_elt_objfile (struct expr_builder *,
 330                                    struct objfile *objfile);
 331
 332 extern void write_exp_msymbol (struct expr_builder *,
 333                                struct bound_minimal_symbol);
 334
 335 extern void write_dollar_variable (struct parser_state *, struct stoken str);
 336
 337 extern const char *find_template_name_end (const char *);
 338
 339 extern std::string copy_name (struct stoken);
 340
 341 extern int dump_subexp (struct expression *, struct ui_file *, int);
 342
 343 extern int dump_subexp_body_standard (struct expression *,
 344                                       struct ui_file *, int);
 345
 346 /* Dump (to STREAM) a function call like expression at position ELT in the
 347    expression array EXP.  Return a new value for ELT just after the
 348    function call expression.  */
 349
 350 extern int dump_subexp_body_funcall (struct expression *exp,
 351                                      struct ui_file *stream, int elt);
 352
 353 extern void operator_length (const struct expression *, int, int *, int *);
 354
 355 extern void operator_length_standard (const struct expression *, int, int *,
 356                                       int *);
 357
 358 extern int operator_check_standard (struct expression *exp, int pos,
 359                                     int (*objfile_func)
 360                                       (struct objfile *objfile, void *data),
 361                                     void *data);
 362
 363 extern bool parse_float (const char *p, int len,
 364                          const struct type *type, gdb_byte *data);
 365 \f
 366 /* These codes indicate operator precedences for expression printing,
 367    least tightly binding first.  */
 368 /* Adding 1 to a precedence value is done for binary operators,
 369    on the operand which is more tightly bound, so that operators
 370    of equal precedence within that operand will get parentheses.  */
 371 /* PREC_HYPER and PREC_ABOVE_COMMA are not the precedence of any operator;
 372    they are used as the "surrounding precedence" to force
 373    various kinds of things to be parenthesized.  */
 374 enum precedence
 375   {
 376     PREC_NULL, PREC_COMMA, PREC_ABOVE_COMMA, PREC_ASSIGN, PREC_LOGICAL_OR,
 377     PREC_LOGICAL_AND, PREC_BITWISE_IOR, PREC_BITWISE_AND, PREC_BITWISE_XOR,
 378     PREC_EQUAL, PREC_ORDER, PREC_SHIFT, PREC_ADD, PREC_MUL, PREC_REPEAT,
 379     PREC_HYPER, PREC_PREFIX, PREC_SUFFIX, PREC_BUILTIN_FUNCTION
 380   };
 381
 382 /* Table mapping opcodes into strings for printing operators
 383    and precedences of the operators.  */
 384
 385 struct op_print
 386   {
 387     const char *string;
 388     enum exp_opcode opcode;
 389     /* Precedence of operator.  These values are used only by comparisons.  */
 390     enum precedence precedence;
 391
 392     /* For a binary operator:  1 iff right associate.
 393        For a unary operator:  1 iff postfix.  */
 394     int right_assoc;
 395   };
 396
 397 /* Information needed to print, prefixify, and evaluate expressions for
 398    a given language.  */
 399
 400 struct exp_descriptor
 401   {
 402     /* Print subexpression.  */
 403     void (*print_subexp) (struct expression *, int *, struct ui_file *,
 404                           enum precedence);
 405
 406     /* Returns number of exp_elements needed to represent an operator and
 407        the number of subexpressions it takes.  */
 408     void (*operator_length) (const struct expression*, int, int*, int *);
 409
 410     /* Call OBJFILE_FUNC for any objfile found being referenced by the
 411        single operator of EXP at position POS.  Operator parameters are
 412        located at positive (POS + number) offsets in EXP.  OBJFILE_FUNC
 413        should never be called with NULL OBJFILE.  OBJFILE_FUNC should
 414        get passed an arbitrary caller supplied DATA pointer.  If it
 415        returns non-zero value then (any other) non-zero value should be
 416        immediately returned to the caller.  Otherwise zero should be
 417        returned.  */
 418     int (*operator_check) (struct expression *exp, int pos,
 419                            int (*objfile_func) (struct objfile *objfile,
 420                                                 void *data),
 421                            void *data);
 422
 423     /* Dump the rest of this (prefix) expression after the operator
 424        itself has been printed.  See dump_subexp_body_standard in
 425        (expprint.c).  */
 426     int (*dump_subexp_body) (struct expression *, struct ui_file *, int);
 427
 428     /* Evaluate an expression.  */
 429     struct value *(*evaluate_exp) (struct type *, struct expression *,
 430                                    int *, enum noside);
 431   };
 432
 433
 434 /* Default descriptor containing standard definitions of all
 435    elements.  */
 436 extern const struct exp_descriptor exp_descriptor_standard;
 437
 438 /* Functions used by language-specific extended operators to (recursively)
 439    print/dump subexpressions.  */
 440
 441 extern void print_subexp (struct expression *, int *, struct ui_file *,
 442                           enum precedence);
 443
 444 extern void print_subexp_standard (struct expression *, int *,
 445                                    struct ui_file *, enum precedence);
 446
 447 /* Print a function call like expression to STREAM.  This is called as a
 448    helper function by which point the expression node identifying this as a
 449    function call has already been stripped off and POS should point to the
 450    number of function call arguments.  EXP is the object containing the
 451    list of expression elements.  */
 452
 453 extern void print_subexp_funcall (struct expression *exp, int *pos,
 454                                   struct ui_file *stream);
 455
 456 /* Function used to avoid direct calls to fprintf
 457    in the code generated by the bison parser.  */
 458
 459 extern void parser_fprintf (FILE *, const char *, ...) ATTRIBUTE_PRINTF (2, 3);
 460
 461 extern int exp_uses_objfile (struct expression *exp, struct objfile *objfile);
 462
 463 #endif /* PARSER_DEFS_H */
 464