gdb/parser-defs.h

   1 /* Parser definitions for GDB.
   2
   3    Copyright (C) 1986-2018 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 "vec.h"
  27 #include "expression.h"
  28
  29 struct block;
  30 struct language_defn;
  31 struct internalvar;
  32
  33 extern int parser_debug;
  34
  35 #define parse_gdbarch(ps) ((ps)->expout->gdbarch)
  36 #define parse_language(ps) ((ps)->expout->language_defn)
  37
  38 struct parser_state
  39 {
  40   /* Constructor.  INITIAL_SIZE is the initial size of the expout
  41      array.  LANG is the language used to parse the expression.  And
  42      GDBARCH is the gdbarch to use during parsing.  */
  43
  44   parser_state (size_t initial_size, const struct language_defn *lang,
  45                 struct gdbarch *gdbarch);
  46
  47   DISABLE_COPY_AND_ASSIGN (parser_state);
  48
  49   /* Resize the allocated expression to the correct size, and return
  50      it as an expression_up -- passing ownership to the caller.  */
  51   expression_up release ();
  52
  53   /* The size of the expression above.  */
  54
  55   size_t expout_size;
  56
  57   /* The expression related to this parser state.  */
  58
  59   expression_up expout;
  60
  61   /* The number of elements already in the expression.  This is used
  62      to know where to put new elements.  */
  63
  64   size_t expout_ptr;
  65 };
  66
  67 /* If this is nonzero, this block is used as the lexical context
  68    for symbol names.  */
  69
  70 extern const struct block *expression_context_block;
  71
  72 /* If expression_context_block is non-zero, then this is the PC within
  73    the block that we want to evaluate expressions at.  When debugging
  74    C or C++ code, we use this to find the exact line we're at, and
  75    then look up the macro definitions active at that point.  */
  76 extern CORE_ADDR expression_context_pc;
  77
  78 /* While parsing expressions we need to track the innermost lexical block
  79    that we encounter.  In some situations we need to track the innermost
  80    block just for symbols, and in other situations we want to track the
  81    innermost block for symbols and registers.  These flags are used by the
  82    innermost block tracker to control which blocks we consider for the
  83    innermost block.  These flags can be combined together as needed.  */
  84
  85 enum innermost_block_tracker_type
  86 {
  87   /* Track the innermost block for symbols within an expression.  */
  88   INNERMOST_BLOCK_FOR_SYMBOLS = (1 << 0),
  89
  90   /* Track the innermost block for registers within an expression.  */
  91   INNERMOST_BLOCK_FOR_REGISTERS = (1 << 1)
  92 };
  93 DEF_ENUM_FLAGS_TYPE (enum innermost_block_tracker_type,
  94                      innermost_block_tracker_types);
  95
  96 /* When parsing expressions we track the innermost block that was
  97    referenced.  */
  98
  99 class innermost_block_tracker
 100 {
 101 public:
 102   innermost_block_tracker ()
 103     : m_types (INNERMOST_BLOCK_FOR_SYMBOLS),
 104       m_innermost_block (NULL)
 105   { /* Nothing.  */ }
 106
 107   /* Reset the currently stored innermost block.  Usually called before
 108      parsing a new expression.  As the most common case is that we only
 109      want to gather the innermost block for symbols in an expression, this
 110      becomes the default block tracker type.  */
 111   void reset (innermost_block_tracker_types t = INNERMOST_BLOCK_FOR_SYMBOLS)
 112   {
 113     m_types = t;
 114     m_innermost_block = NULL;
 115   }
 116
 117   /* Update the stored innermost block if the new block B is more inner
 118      than the currently stored block, or if no block is stored yet.  The
 119      type T tells us whether the block B was for a symbol or for a
 120      register.  The stored innermost block is only updated if the type T is
 121      a type we are interested in, the types we are interested in are held
 122      in M_TYPES and set during RESET.  */
 123   void update (const struct block *b, innermost_block_tracker_types t);
 124
 125   /* Overload of main UPDATE method which extracts the block from BS.  */
 126   void update (const struct block_symbol &bs)
 127   {
 128     update (bs.block, INNERMOST_BLOCK_FOR_SYMBOLS);
 129   }
 130
 131   /* Return the stored innermost block.  Can be nullptr if no symbols or
 132      registers were found during an expression parse, and so no innermost
 133      block was defined.  */
 134   const struct block *block () const
 135   {
 136     return m_innermost_block;
 137   }
 138
 139 private:
 140   /* The type of innermost block being looked for.  */
 141   innermost_block_tracker_types m_types;
 142
 143   /* The currently stored innermost block found while parsing an
 144      expression.  */
 145   const struct block *m_innermost_block;
 146 };
 147
 148 /* The innermost context required by the stack and register variables
 149    we've encountered so far.  This should be cleared before parsing an
 150    expression, and queried once the parse is complete.  */
 151 extern innermost_block_tracker innermost_block;
 152
 153 /* Number of arguments seen so far in innermost function call.  */
 154 extern int arglist_len;
 155
 156 /* A string token, either a char-string or bit-string.  Char-strings are
 157    used, for example, for the names of symbols.  */
 158
 159 struct stoken
 160   {
 161     /* Pointer to first byte of char-string or first bit of bit-string.  */
 162     const char *ptr;
 163     /* Length of string in bytes for char-string or bits for bit-string.  */
 164     int length;
 165   };
 166
 167 struct typed_stoken
 168   {
 169     /* A language-specific type field.  */
 170     int type;
 171     /* Pointer to first byte of char-string or first bit of bit-string.  */
 172     char *ptr;
 173     /* Length of string in bytes for char-string or bits for bit-string.  */
 174     int length;
 175   };
 176
 177 struct stoken_vector
 178   {
 179     int len;
 180     struct typed_stoken *tokens;
 181   };
 182
 183 struct ttype
 184   {
 185     struct stoken stoken;
 186     struct type *type;
 187   };
 188
 189 struct symtoken
 190   {
 191     struct stoken stoken;
 192     struct block_symbol sym;
 193     int is_a_field_of_this;
 194   };
 195
 196 struct objc_class_str
 197   {
 198     struct stoken stoken;
 199     struct type *type;
 200     int theclass;
 201   };
 202
 203 typedef struct type *type_ptr;
 204 DEF_VEC_P (type_ptr);
 205
 206 /* For parsing of complicated types.
 207    An array should be preceded in the list by the size of the array.  */
 208 enum type_pieces
 209   {
 210     tp_end = -1,
 211     tp_pointer,
 212     tp_reference,
 213     tp_rvalue_reference,
 214     tp_array,
 215     tp_function,
 216     tp_function_with_arguments,
 217     tp_const,
 218     tp_volatile,
 219     tp_space_identifier,
 220     tp_type_stack
 221   };
 222 /* The stack can contain either an enum type_pieces or an int.  */
 223 union type_stack_elt
 224   {
 225     enum type_pieces piece;
 226     int int_val;
 227     struct type_stack *stack_val;
 228     VEC (type_ptr) *typelist_val;
 229   };
 230
 231 /* The type stack is an instance of this structure.  */
 232
 233 struct type_stack
 234 {
 235   /* Elements on the stack.  */
 236   std::vector<union type_stack_elt> elements;
 237 };
 238
 239 /* Reverse an expression from suffix form (in which it is constructed)
 240    to prefix form (in which we can conveniently print or execute it).
 241    Ordinarily this always returns -1.  However, if EXPOUT_LAST_STRUCT
 242    is not -1 (i.e., we are trying to complete a field name), it will
 243    return the index of the subexpression which is the left-hand-side
 244    of the struct operation at EXPOUT_LAST_STRUCT.  */
 245
 246 extern int prefixify_expression (struct expression *expr);
 247
 248 extern void write_exp_elt_opcode (struct parser_state *, enum exp_opcode);
 249
 250 extern void write_exp_elt_sym (struct parser_state *, struct symbol *);
 251
 252 extern void write_exp_elt_longcst (struct parser_state *, LONGEST);
 253
 254 extern void write_exp_elt_floatcst (struct parser_state *, const gdb_byte *);
 255
 256 extern void write_exp_elt_type (struct parser_state *, struct type *);
 257
 258 extern void write_exp_elt_intern (struct parser_state *, struct internalvar *);
 259
 260 extern void write_exp_string (struct parser_state *, struct stoken);
 261
 262 void write_exp_string_vector (struct parser_state *, int type,
 263                               struct stoken_vector *vec);
 264
 265 extern void write_exp_bitstring (struct parser_state *, struct stoken);
 266
 267 extern void write_exp_elt_block (struct parser_state *, const struct block *);
 268
 269 extern void write_exp_elt_objfile (struct parser_state *,
 270                                    struct objfile *objfile);
 271
 272 extern void write_exp_msymbol (struct parser_state *,
 273                                struct bound_minimal_symbol);
 274
 275 extern void write_dollar_variable (struct parser_state *, struct stoken str);
 276
 277 extern void mark_struct_expression (struct parser_state *);
 278
 279 extern const char *find_template_name_end (const char *);
 280
 281 extern void start_arglist (void);
 282
 283 extern int end_arglist (void);
 284
 285 extern char *copy_name (struct stoken);
 286
 287 extern void insert_type (enum type_pieces);
 288
 289 extern void push_type (enum type_pieces);
 290
 291 extern void push_type_int (int);
 292
 293 extern void insert_type_address_space (struct parser_state *, char *);
 294
 295 extern enum type_pieces pop_type (void);
 296
 297 extern int pop_type_int (void);
 298
 299 extern struct type_stack *get_type_stack (void);
 300
 301 extern struct type_stack *append_type_stack (struct type_stack *to,
 302                                              struct type_stack *from);
 303
 304 extern void push_type_stack (struct type_stack *stack);
 305
 306 extern void type_stack_cleanup (void *arg);
 307
 308 extern void push_typelist (VEC (type_ptr) *typelist);
 309
 310 extern int dump_subexp (struct expression *, struct ui_file *, int);
 311
 312 extern int dump_subexp_body_standard (struct expression *,
 313                                       struct ui_file *, int);
 314
 315 extern void operator_length (const struct expression *, int, int *, int *);
 316
 317 extern void operator_length_standard (const struct expression *, int, int *,
 318                                       int *);
 319
 320 extern int operator_check_standard (struct expression *exp, int pos,
 321                                     int (*objfile_func)
 322                                       (struct objfile *objfile, void *data),
 323                                     void *data);
 324
 325 extern const char *op_name_standard (enum exp_opcode);
 326
 327 extern struct type *follow_types (struct type *);
 328
 329 extern type_instance_flags follow_type_instance_flags ();
 330
 331 extern void null_post_parser (expression_up *, int);
 332
 333 extern bool parse_float (const char *p, int len,
 334                          const struct type *type, gdb_byte *data);
 335
 336 /* During parsing of a C expression, the pointer to the next character
 337    is in this variable.  */
 338
 339 extern const char *lexptr;
 340
 341 /* After a token has been recognized, this variable points to it.
 342    Currently used only for error reporting.  */
 343 extern const char *prev_lexptr;
 344
 345 /* Current depth in parentheses within the expression.  */
 346
 347 extern int paren_depth;
 348
 349 /* Nonzero means stop parsing on first comma (if not within parentheses).  */
 350
 351 extern int comma_terminates;
 352 \f
 353 /* These codes indicate operator precedences for expression printing,
 354    least tightly binding first.  */
 355 /* Adding 1 to a precedence value is done for binary operators,
 356    on the operand which is more tightly bound, so that operators
 357    of equal precedence within that operand will get parentheses.  */
 358 /* PREC_HYPER and PREC_ABOVE_COMMA are not the precedence of any operator;
 359    they are used as the "surrounding precedence" to force
 360    various kinds of things to be parenthesized.  */
 361 enum precedence
 362   {
 363     PREC_NULL, PREC_COMMA, PREC_ABOVE_COMMA, PREC_ASSIGN, PREC_LOGICAL_OR,
 364     PREC_LOGICAL_AND, PREC_BITWISE_IOR, PREC_BITWISE_AND, PREC_BITWISE_XOR,
 365     PREC_EQUAL, PREC_ORDER, PREC_SHIFT, PREC_ADD, PREC_MUL, PREC_REPEAT,
 366     PREC_HYPER, PREC_PREFIX, PREC_SUFFIX, PREC_BUILTIN_FUNCTION
 367   };
 368
 369 /* Table mapping opcodes into strings for printing operators
 370    and precedences of the operators.  */
 371
 372 struct op_print
 373   {
 374     const char *string;
 375     enum exp_opcode opcode;
 376     /* Precedence of operator.  These values are used only by comparisons.  */
 377     enum precedence precedence;
 378
 379     /* For a binary operator:  1 iff right associate.
 380        For a unary operator:  1 iff postfix.  */
 381     int right_assoc;
 382   };
 383
 384 /* Information needed to print, prefixify, and evaluate expressions for
 385    a given language.  */
 386
 387 struct exp_descriptor
 388   {
 389     /* Print subexpression.  */
 390     void (*print_subexp) (struct expression *, int *, struct ui_file *,
 391                           enum precedence);
 392
 393     /* Returns number of exp_elements needed to represent an operator and
 394        the number of subexpressions it takes.  */
 395     void (*operator_length) (const struct expression*, int, int*, int *);
 396
 397     /* Call OBJFILE_FUNC for any objfile found being referenced by the
 398        single operator of EXP at position POS.  Operator parameters are
 399        located at positive (POS + number) offsets in EXP.  OBJFILE_FUNC
 400        should never be called with NULL OBJFILE.  OBJFILE_FUNC should
 401        get passed an arbitrary caller supplied DATA pointer.  If it
 402        returns non-zero value then (any other) non-zero value should be
 403        immediately returned to the caller.  Otherwise zero should be
 404        returned.  */
 405     int (*operator_check) (struct expression *exp, int pos,
 406                            int (*objfile_func) (struct objfile *objfile,
 407                                                 void *data),
 408                            void *data);
 409
 410     /* Name of this operator for dumping purposes.
 411        The returned value should never be NULL, even if EXP_OPCODE is
 412        an unknown opcode (a string containing an image of the numeric
 413        value of the opcode can be returned, for instance).  */
 414     const char *(*op_name) (enum exp_opcode);
 415
 416     /* Dump the rest of this (prefix) expression after the operator
 417        itself has been printed.  See dump_subexp_body_standard in
 418        (expprint.c).  */
 419     int (*dump_subexp_body) (struct expression *, struct ui_file *, int);
 420
 421     /* Evaluate an expression.  */
 422     struct value *(*evaluate_exp) (struct type *, struct expression *,
 423                                    int *, enum noside);
 424   };
 425
 426
 427 /* Default descriptor containing standard definitions of all
 428    elements.  */
 429 extern const struct exp_descriptor exp_descriptor_standard;
 430
 431 /* Functions used by language-specific extended operators to (recursively)
 432    print/dump subexpressions.  */
 433
 434 extern void print_subexp (struct expression *, int *, struct ui_file *,
 435                           enum precedence);
 436
 437 extern void print_subexp_standard (struct expression *, int *,
 438                                    struct ui_file *, enum precedence);
 439
 440 /* Function used to avoid direct calls to fprintf
 441    in the code generated by the bison parser.  */
 442
 443 extern void parser_fprintf (FILE *, const char *, ...) ATTRIBUTE_PRINTF (2, 3);
 444
 445 extern int exp_uses_objfile (struct expression *exp, struct objfile *objfile);
 446
 447 extern void mark_completion_tag (enum type_code, const char *ptr,
 448                                  int length);
 449
 450 /* Reallocate the `expout' pointer inside PS so that it can accommodate
 451    at least LENELT expression elements.  This function does nothing if
 452    there is enough room for the elements.  */
 453
 454 extern void increase_expout_size (struct parser_state *ps, size_t lenelt);
 455
 456 #endif /* PARSER_DEFS_H */
 457