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 #include "expop.h"
  29
  30 struct block;
  31 struct language_defn;
  32 struct internalvar;
  33 class innermost_block_tracker;
  34
  35 extern bool 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   /* Set the root operation of the expression that is currently being
  68      built.  */
  69   void set_operation (expr::operation_up &&op)
  70   {
  71     expout->op = std::move (op);
  72   }
  73
  74   /* The expression related to this parser state.  */
  75
  76   expression_up expout;
  77 };
  78
  79 /* This is used for expression completion.  */
  80
  81 struct expr_completion_state
  82 {
  83   /* The last struct expression directly before a '.' or '->'.  This
  84      is set when parsing and is only used when completing a field
  85      name.  It is nullptr if no dereference operation was found.  */
  86   expr::structop_base_operation *expout_last_op = nullptr;
  87
  88   /* If we are completing a tagged type name, this will be nonzero.  */
  89   enum type_code expout_tag_completion_type = TYPE_CODE_UNDEF;
  90
  91   /* The token for tagged type name completion.  */
  92   gdb::unique_xmalloc_ptr<char> expout_completion_name;
  93 };
  94
  95 /* An instance of this type is instantiated during expression parsing,
  96    and passed to the appropriate parser.  It holds both inputs to the
  97    parser, and result.  */
  98
  99 struct parser_state : public expr_builder
 100 {
 101   /* Constructor.  LANG is the language used to parse the expression.
 102      And GDBARCH is the gdbarch to use during parsing.  */
 103
 104   parser_state (const struct language_defn *lang,
 105                 struct gdbarch *gdbarch,
 106                 const struct block *context_block,
 107                 CORE_ADDR context_pc,
 108                 int comma,
 109                 const char *input,
 110                 int completion,
 111                 innermost_block_tracker *tracker,
 112                 bool void_p)
 113     : expr_builder (lang, gdbarch),
 114       expression_context_block (context_block),
 115       expression_context_pc (context_pc),
 116       comma_terminates (comma),
 117       lexptr (input),
 118       parse_completion (completion),
 119       block_tracker (tracker),
 120       void_context_p (void_p)
 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 given operation as the starting location of a structure
 147      expression.  This is used when completing on field names.  */
 148
 149   void mark_struct_expression (expr::structop_base_operation *op);
 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   /* Push an operation on the stack.  */
 158   void push (expr::operation_up &&op)
 159   {
 160     m_operations.push_back (std::move (op));
 161   }
 162
 163   /* Create a new operation and push it on the stack.  */
 164   template<typename T, typename... Arg>
 165   void push_new (Arg... args)
 166   {
 167     m_operations.emplace_back (new T (std::forward<Arg> (args)...));
 168   }
 169
 170   /* Push a new C string operation.  */
 171   void push_c_string (int, struct stoken_vector *vec);
 172
 173   /* Push a symbol reference.  If SYM is nullptr, look for a minimal
 174      symbol.  */
 175   void push_symbol (const char *name, block_symbol sym);
 176
 177   /* Push a reference to $mumble.  This may result in a convenience
 178      variable, a history reference, or a register.  */
 179   void push_dollar (struct stoken str);
 180
 181   /* Pop an operation from the stack.  */
 182   expr::operation_up pop ()
 183   {
 184     expr::operation_up result = std::move (m_operations.back ());
 185     m_operations.pop_back ();
 186     return result;
 187   }
 188
 189   /* Pop N elements from the stack and return a vector.  */
 190   std::vector<expr::operation_up> pop_vector (int n)
 191   {
 192     std::vector<expr::operation_up> result (n);
 193     for (int i = 1; i <= n; ++i)
 194       result[n - i] = pop ();
 195     return result;
 196   }
 197
 198   /* A helper that pops an operation, wraps it in some other
 199      operation, and pushes it again.  */
 200   template<typename T>
 201   void wrap ()
 202   {
 203     using namespace expr;
 204     operation_up v = ::expr::make_operation<T> (pop ());
 205     push (std::move (v));
 206   }
 207
 208   /* A helper that pops two operations, wraps them in some other
 209      operation, and pushes the result.  */
 210   template<typename T>
 211   void wrap2 ()
 212   {
 213     expr::operation_up rhs = pop ();
 214     expr::operation_up lhs = pop ();
 215     push (expr::make_operation<T> (std::move (lhs), std::move (rhs)));
 216   }
 217
 218   /* If this is nonzero, this block is used as the lexical context for
 219      symbol names.  */
 220
 221   const struct block * const expression_context_block;
 222
 223   /* If expression_context_block is non-zero, then this is the PC
 224      within the block that we want to evaluate expressions at.  When
 225      debugging C or C++ code, we use this to find the exact line we're
 226      at, and then look up the macro definitions active at that
 227      point.  */
 228   const CORE_ADDR expression_context_pc;
 229
 230   /* Nonzero means stop parsing on first comma (if not within parentheses).  */
 231
 232   int comma_terminates;
 233
 234   /* During parsing of a C expression, the pointer to the next character
 235      is in this variable.  */
 236
 237   const char *lexptr;
 238
 239   /* After a token has been recognized, this variable points to it.
 240      Currently used only for error reporting.  */
 241   const char *prev_lexptr = nullptr;
 242
 243   /* Number of arguments seen so far in innermost function call.  */
 244
 245   int arglist_len = 0;
 246
 247   /* True if parsing an expression to attempt completion.  */
 248   int parse_completion;
 249
 250   /* Completion state is updated here.  */
 251   expr_completion_state m_completion_state;
 252
 253   /* The innermost block tracker.  */
 254   innermost_block_tracker *block_tracker;
 255
 256   /* True if no value is expected from the expression.  */
 257   bool void_context_p;
 258
 259 private:
 260
 261   /* Data structure for saving values of arglist_len for function calls whose
 262      arguments contain other function calls.  */
 263
 264   std::vector<int> m_funcall_chain;
 265
 266   /* Stack of operations.  */
 267   std::vector<expr::operation_up> m_operations;
 268 };
 269
 270 /* When parsing expressions we track the innermost block that was
 271    referenced.  */
 272
 273 class innermost_block_tracker
 274 {
 275 public:
 276   innermost_block_tracker (innermost_block_tracker_types types
 277                            = INNERMOST_BLOCK_FOR_SYMBOLS)
 278     : m_types (types),
 279       m_innermost_block (NULL)
 280   { /* Nothing.  */ }
 281
 282   /* Update the stored innermost block if the new block B is more inner
 283      than the currently stored block, or if no block is stored yet.  The
 284      type T tells us whether the block B was for a symbol or for a
 285      register.  The stored innermost block is only updated if the type T is
 286      a type we are interested in, the types we are interested in are held
 287      in M_TYPES and set during RESET.  */
 288   void update (const struct block *b, innermost_block_tracker_types t);
 289
 290   /* Overload of main UPDATE method which extracts the block from BS.  */
 291   void update (const struct block_symbol &bs)
 292   {
 293     update (bs.block, INNERMOST_BLOCK_FOR_SYMBOLS);
 294   }
 295
 296   /* Return the stored innermost block.  Can be nullptr if no symbols or
 297      registers were found during an expression parse, and so no innermost
 298      block was defined.  */
 299   const struct block *block () const
 300   {
 301     return m_innermost_block;
 302   }
 303
 304 private:
 305   /* The type of innermost block being looked for.  */
 306   innermost_block_tracker_types m_types;
 307
 308   /* The currently stored innermost block found while parsing an
 309      expression.  */
 310   const struct block *m_innermost_block;
 311 };
 312
 313 /* A string token, either a char-string or bit-string.  Char-strings are
 314    used, for example, for the names of symbols.  */
 315
 316 struct stoken
 317   {
 318     /* Pointer to first byte of char-string or first bit of bit-string.  */
 319     const char *ptr;
 320     /* Length of string in bytes for char-string or bits for bit-string.  */
 321     int length;
 322   };
 323
 324 struct typed_stoken
 325   {
 326     /* A language-specific type field.  */
 327     int type;
 328     /* Pointer to first byte of char-string or first bit of bit-string.  */
 329     char *ptr;
 330     /* Length of string in bytes for char-string or bits for bit-string.  */
 331     int length;
 332   };
 333
 334 struct stoken_vector
 335   {
 336     int len;
 337     struct typed_stoken *tokens;
 338   };
 339
 340 struct ttype
 341   {
 342     struct stoken stoken;
 343     struct type *type;
 344   };
 345
 346 struct symtoken
 347   {
 348     struct stoken stoken;
 349     struct block_symbol sym;
 350     int is_a_field_of_this;
 351   };
 352
 353 struct objc_class_str
 354   {
 355     struct stoken stoken;
 356     struct type *type;
 357     int theclass;
 358   };
 359
 360 extern const char *find_template_name_end (const char *);
 361
 362 extern std::string copy_name (struct stoken);
 363
 364 extern bool parse_float (const char *p, int len,
 365                          const struct type *type, gdb_byte *data);
 366 \f
 367
 368 /* Function used to avoid direct calls to fprintf
 369    in the code generated by the bison parser.  */
 370
 371 extern void parser_fprintf (FILE *, const char *, ...) ATTRIBUTE_PRINTF (2, 3);
 372
 373 extern int exp_uses_objfile (struct expression *exp, struct objfile *objfile);
 374
 375 #endif /* PARSER_DEFS_H */
 376