gdb/parser-defs.h

   1 /* Parser definitions for GDB.
   2
   3    Copyright (C) 1986-2019 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 "gdbsupport/vec.h"
  27 #include "expression.h"
  28 #include "symtab.h"
  29
  30 struct block;
  31 struct language_defn;
  32 struct internalvar;
  33 class innermost_block_tracker;
  34
  35 extern int parser_debug;
  36
  37 /* A class that can be used to build a "struct expression".  */
  38
  39 struct expr_builder
  40 {
  41   /* Constructor.  LANG is the language used to parse the expression.
  42      And GDBARCH is the gdbarch to use during parsing.  */
  43
  44   expr_builder (const struct language_defn *lang,
  45                 struct gdbarch *gdbarch);
  46
  47   DISABLE_COPY_AND_ASSIGN (expr_builder);
  48
  49   /* Resize the allocated expression to the correct size, and return
  50      it as an expression_up -- passing ownership to the caller.  */
  51   ATTRIBUTE_UNUSED_RESULT expression_up release ();
  52
  53   /* Return the gdbarch that was passed to the constructor.  */
  54
  55   struct gdbarch *gdbarch ()
  56   {
  57     return expout->gdbarch;
  58   }
  59
  60   /* Return the language that was passed to the constructor.  */
  61
  62   const struct language_defn *language ()
  63   {
  64     return expout->language_defn;
  65   }
  66
  67   /* The size of the expression above.  */
  68
  69   size_t expout_size;
  70
  71   /* The expression related to this parser state.  */
  72
  73   expression_up expout;
  74
  75   /* The number of elements already in the expression.  This is used
  76      to know where to put new elements.  */
  77
  78   size_t expout_ptr;
  79 };
  80
  81 /* This is used for expression completion.  */
  82
  83 struct expr_completion_state
  84 {
  85   /* The index of the last struct expression directly before a '.' or
  86      '->'.  This is set when parsing and is only used when completing a
  87      field name.  It is -1 if no dereference operation was found.  */
  88   int expout_last_struct = -1;
  89
  90   /* If we are completing a tagged type name, this will be nonzero.  */
  91   enum type_code expout_tag_completion_type = TYPE_CODE_UNDEF;
  92
  93   /* The token for tagged type name completion.  */
  94   gdb::unique_xmalloc_ptr<char> expout_completion_name;
  95 };
  96
  97 /* An instance of this type is instantiated during expression parsing,
  98    and passed to the appropriate parser.  It holds both inputs to the
  99    parser, and result.  */
 100
 101 struct parser_state : public expr_builder
 102 {
 103   /* Constructor.  LANG is the language used to parse the expression.
 104      And GDBARCH is the gdbarch to use during parsing.  */
 105
 106   parser_state (const struct language_defn *lang,
 107                 struct gdbarch *gdbarch,
 108                 const struct block *context_block,
 109                 CORE_ADDR context_pc,
 110                 int comma,
 111                 const char *input,
 112                 int completion,
 113                 innermost_block_tracker *tracker)
 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   {
 122   }
 123
 124   DISABLE_COPY_AND_ASSIGN (parser_state);
 125
 126   /* Begin counting arguments for a function call,
 127      saving the data about any containing call.  */
 128
 129   void start_arglist ()
 130   {
 131     m_funcall_chain.push_back (arglist_len);
 132     arglist_len = 0;
 133   }
 134
 135   /* Return the number of arguments in a function call just terminated,
 136      and restore the data for the containing function call.  */
 137
 138   int end_arglist ()
 139   {
 140     int val = arglist_len;
 141     arglist_len = m_funcall_chain.back ();
 142     m_funcall_chain.pop_back ();
 143     return val;
 144   }
 145
 146   /* Mark the current index as the starting location of a structure
 147      expression.  This is used when completing on field names.  */
 148
 149   void mark_struct_expression ();
 150
 151   /* Indicate that the current parser invocation is completing a tag.
 152      TAG is the type code of the tag, and PTR and LENGTH represent the
 153      start of the tag name.  */
 154
 155   void mark_completion_tag (enum type_code tag, const char *ptr, int length);
 156
 157
 158   /* If this is nonzero, this block is used as the lexical context for
 159      symbol names.  */
 160
 161   const struct block * const expression_context_block;
 162
 163   /* If expression_context_block is non-zero, then this is the PC
 164      within the block that we want to evaluate expressions at.  When
 165      debugging C or C++ code, we use this to find the exact line we're
 166      at, and then look up the macro definitions active at that
 167      point.  */
 168   const CORE_ADDR expression_context_pc;
 169
 170   /* Nonzero means stop parsing on first comma (if not within parentheses).  */
 171
 172   int comma_terminates;
 173
 174   /* During parsing of a C expression, the pointer to the next character
 175      is in this variable.  */
 176
 177   const char *lexptr;
 178
 179   /* After a token has been recognized, this variable points to it.
 180      Currently used only for error reporting.  */
 181   const char *prev_lexptr = nullptr;
 182
 183   /* Number of arguments seen so far in innermost function call.  */
 184
 185   int arglist_len = 0;
 186
 187   /* True if parsing an expression to attempt completion.  */
 188   int parse_completion;
 189
 190   /* Completion state is updated here.  */
 191   expr_completion_state m_completion_state;
 192
 193   /* The innermost block tracker.  */
 194   innermost_block_tracker *block_tracker;
 195
 196 private:
 197
 198   /* Data structure for saving values of arglist_len for function calls whose
 199      arguments contain other function calls.  */
 200
 201   std::vector<int> m_funcall_chain;
 202 };
 203
 204 /* When parsing expressions we track the innermost block that was
 205    referenced.  */
 206
 207 class innermost_block_tracker
 208 {
 209 public:
 210   innermost_block_tracker (innermost_block_tracker_types types
 211                            = INNERMOST_BLOCK_FOR_SYMBOLS)
 212     : m_types (types),
 213       m_innermost_block (NULL)
 214   { /* Nothing.  */ }
 215
 216   /* Update the stored innermost block if the new block B is more inner
 217      than the currently stored block, or if no block is stored yet.  The
 218      type T tells us whether the block B was for a symbol or for a
 219      register.  The stored innermost block is only updated if the type T is
 220      a type we are interested in, the types we are interested in are held
 221      in M_TYPES and set during RESET.  */
 222   void update (const struct block *b, innermost_block_tracker_types t);
 223
 224   /* Overload of main UPDATE method which extracts the block from BS.  */
 225   void update (const struct block_symbol &bs)
 226   {
 227     update (bs.block, INNERMOST_BLOCK_FOR_SYMBOLS);
 228   }
 229
 230   /* Return the stored innermost block.  Can be nullptr if no symbols or
 231      registers were found during an expression parse, and so no innermost
 232      block was defined.  */
 233   const struct block *block () const
 234   {
 235     return m_innermost_block;
 236   }
 237
 238 private:
 239   /* The type of innermost block being looked for.  */
 240   innermost_block_tracker_types m_types;
 241
 242   /* The currently stored innermost block found while parsing an
 243      expression.  */
 244   const struct block *m_innermost_block;
 245 };
 246
 247 /* A string token, either a char-string or bit-string.  Char-strings are
 248    used, for example, for the names of symbols.  */
 249
 250 struct stoken
 251   {
 252     /* Pointer to first byte of char-string or first bit of bit-string.  */
 253     const char *ptr;
 254     /* Length of string in bytes for char-string or bits for bit-string.  */
 255     int length;
 256   };
 257
 258 struct typed_stoken
 259   {
 260     /* A language-specific type field.  */
 261     int type;
 262     /* Pointer to first byte of char-string or first bit of bit-string.  */
 263     char *ptr;
 264     /* Length of string in bytes for char-string or bits for bit-string.  */
 265     int length;
 266   };
 267
 268 struct stoken_vector
 269   {
 270     int len;
 271     struct typed_stoken *tokens;
 272   };
 273
 274 struct ttype
 275   {
 276     struct stoken stoken;
 277     struct type *type;
 278   };
 279
 280 struct symtoken
 281   {
 282     struct stoken stoken;
 283     struct block_symbol sym;
 284     int is_a_field_of_this;
 285   };
 286
 287 struct objc_class_str
 288   {
 289     struct stoken stoken;
 290     struct type *type;
 291     int theclass;
 292   };
 293
 294 /* Reverse an expression from suffix form (in which it is constructed)
 295    to prefix form (in which we can conveniently print or execute it).
 296    Ordinarily this always returns -1.  However, if LAST_STRUCT
 297    is not -1 (i.e., we are trying to complete a field name), it will
 298    return the index of the subexpression which is the left-hand-side
 299    of the struct operation at LAST_STRUCT.  */
 300
 301 extern int prefixify_expression (struct expression *expr,
 302                                  int last_struct = -1);
 303
 304 extern void write_exp_elt_opcode (struct expr_builder *, enum exp_opcode);
 305
 306 extern void write_exp_elt_sym (struct expr_builder *, struct symbol *);
 307
 308 extern void write_exp_elt_longcst (struct expr_builder *, LONGEST);
 309
 310 extern void write_exp_elt_floatcst (struct expr_builder *, const gdb_byte *);
 311
 312 extern void write_exp_elt_type (struct expr_builder *, struct type *);
 313
 314 extern void write_exp_elt_intern (struct expr_builder *, struct internalvar *);
 315
 316 extern void write_exp_string (struct expr_builder *, struct stoken);
 317
 318 void write_exp_string_vector (struct expr_builder *, int type,
 319                               struct stoken_vector *vec);
 320
 321 extern void write_exp_bitstring (struct expr_builder *, struct stoken);
 322
 323 extern void write_exp_elt_block (struct expr_builder *, const struct block *);
 324
 325 extern void write_exp_elt_objfile (struct expr_builder *,
 326                                    struct objfile *objfile);
 327
 328 extern void write_exp_msymbol (struct expr_builder *,
 329                                struct bound_minimal_symbol);
 330
 331 extern void write_dollar_variable (struct parser_state *, struct stoken str);
 332
 333 extern const char *find_template_name_end (const char *);
 334
 335 extern std::string copy_name (struct stoken);
 336
 337 extern int dump_subexp (struct expression *, struct ui_file *, int);
 338
 339 extern int dump_subexp_body_standard (struct expression *,
 340                                       struct ui_file *, int);
 341
 342 extern void operator_length (const struct expression *, int, int *, int *);
 343
 344 extern void operator_length_standard (const struct expression *, int, int *,
 345                                       int *);
 346
 347 extern int operator_check_standard (struct expression *exp, int pos,
 348                                     int (*objfile_func)
 349                                       (struct objfile *objfile, void *data),
 350                                     void *data);
 351
 352 extern const char *op_name_standard (enum exp_opcode);
 353
 354 extern void null_post_parser (expression_up *, int, int,
 355                               innermost_block_tracker *);
 356
 357 extern bool parse_float (const char *p, int len,
 358                          const struct type *type, gdb_byte *data);
 359 \f
 360 /* These codes indicate operator precedences for expression printing,
 361    least tightly binding first.  */
 362 /* Adding 1 to a precedence value is done for binary operators,
 363    on the operand which is more tightly bound, so that operators
 364    of equal precedence within that operand will get parentheses.  */
 365 /* PREC_HYPER and PREC_ABOVE_COMMA are not the precedence of any operator;
 366    they are used as the "surrounding precedence" to force
 367    various kinds of things to be parenthesized.  */
 368 enum precedence
 369   {
 370     PREC_NULL, PREC_COMMA, PREC_ABOVE_COMMA, PREC_ASSIGN, PREC_LOGICAL_OR,
 371     PREC_LOGICAL_AND, PREC_BITWISE_IOR, PREC_BITWISE_AND, PREC_BITWISE_XOR,
 372     PREC_EQUAL, PREC_ORDER, PREC_SHIFT, PREC_ADD, PREC_MUL, PREC_REPEAT,
 373     PREC_HYPER, PREC_PREFIX, PREC_SUFFIX, PREC_BUILTIN_FUNCTION
 374   };
 375
 376 /* Table mapping opcodes into strings for printing operators
 377    and precedences of the operators.  */
 378
 379 struct op_print
 380   {
 381     const char *string;
 382     enum exp_opcode opcode;
 383     /* Precedence of operator.  These values are used only by comparisons.  */
 384     enum precedence precedence;
 385
 386     /* For a binary operator:  1 iff right associate.
 387        For a unary operator:  1 iff postfix.  */
 388     int right_assoc;
 389   };
 390
 391 /* Information needed to print, prefixify, and evaluate expressions for
 392    a given language.  */
 393
 394 struct exp_descriptor
 395   {
 396     /* Print subexpression.  */
 397     void (*print_subexp) (struct expression *, int *, struct ui_file *,
 398                           enum precedence);
 399
 400     /* Returns number of exp_elements needed to represent an operator and
 401        the number of subexpressions it takes.  */
 402     void (*operator_length) (const struct expression*, int, int*, int *);
 403
 404     /* Call OBJFILE_FUNC for any objfile found being referenced by the
 405        single operator of EXP at position POS.  Operator parameters are
 406        located at positive (POS + number) offsets in EXP.  OBJFILE_FUNC
 407        should never be called with NULL OBJFILE.  OBJFILE_FUNC should
 408        get passed an arbitrary caller supplied DATA pointer.  If it
 409        returns non-zero value then (any other) non-zero value should be
 410        immediately returned to the caller.  Otherwise zero should be
 411        returned.  */
 412     int (*operator_check) (struct expression *exp, int pos,
 413                            int (*objfile_func) (struct objfile *objfile,
 414                                                 void *data),
 415                            void *data);
 416
 417     /* Name of this operator for dumping purposes.
 418        The returned value should never be NULL, even if EXP_OPCODE is
 419        an unknown opcode (a string containing an image of the numeric
 420        value of the opcode can be returned, for instance).  */
 421     const char *(*op_name) (enum exp_opcode);
 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 /* Function used to avoid direct calls to fprintf
 448    in the code generated by the bison parser.  */
 449
 450 extern void parser_fprintf (FILE *, const char *, ...) ATTRIBUTE_PRINTF (2, 3);
 451
 452 extern int exp_uses_objfile (struct expression *exp, struct objfile *objfile);
 453
 454 #endif /* PARSER_DEFS_H */
 455