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     : expout (new expression (lang, gdbarch))
  47   {
  48   }
  49
  50   DISABLE_COPY_AND_ASSIGN (expr_builder);
  51
  52   /* Resize the allocated expression to the correct size, and return
  53      it as an expression_up -- passing ownership to the caller.  */
  54   ATTRIBUTE_UNUSED_RESULT expression_up release ()
  55   {
  56     return std::move (expout);
  57   }
  58
  59   /* Return the gdbarch that was passed to the constructor.  */
  60
  61   struct gdbarch *gdbarch ()
  62   {
  63     return expout->gdbarch;
  64   }
  65
  66   /* Return the language that was passed to the constructor.  */
  67
  68   const struct language_defn *language ()
  69   {
  70     return expout->language_defn;
  71   }
  72
  73   /* Set the root operation of the expression that is currently being
  74      built.  */
  75   void set_operation (expr::operation_up &&op)
  76   {
  77     expout->op = std::move (op);
  78   }
  79
  80   /* The expression related to this parser state.  */
  81
  82   expression_up expout;
  83 };
  84
  85 /* This is used for expression completion.  */
  86
  87 struct expr_completion_state
  88 {
  89   /* The last struct expression directly before a '.' or '->'.  This
  90      is set when parsing and is only used when completing a field
  91      name.  It is nullptr if no dereference operation was found.  */
  92   expr::structop_base_operation *expout_last_op = nullptr;
  93
  94   /* If we are completing a tagged type name, this will be nonzero.  */
  95   enum type_code expout_tag_completion_type = TYPE_CODE_UNDEF;
  96
  97   /* The token for tagged type name completion.  */
  98   gdb::unique_xmalloc_ptr<char> expout_completion_name;
  99 };
 100
 101 /* An instance of this type is instantiated during expression parsing,
 102    and passed to the appropriate parser.  It holds both inputs to the
 103    parser, and result.  */
 104
 105 struct parser_state : public expr_builder
 106 {
 107   /* Constructor.  LANG is the language used to parse the expression.
 108      And GDBARCH is the gdbarch to use during parsing.  */
 109
 110   parser_state (const struct language_defn *lang,
 111                 struct gdbarch *gdbarch,
 112                 const struct block *context_block,
 113                 CORE_ADDR context_pc,
 114                 int comma,
 115                 const char *input,
 116                 bool completion,
 117                 innermost_block_tracker *tracker,
 118                 bool void_p)
 119     : expr_builder (lang, gdbarch),
 120       expression_context_block (context_block),
 121       expression_context_pc (context_pc),
 122       comma_terminates (comma),
 123       lexptr (input),
 124       parse_completion (completion),
 125       block_tracker (tracker),
 126       void_context_p (void_p)
 127   {
 128   }
 129
 130   DISABLE_COPY_AND_ASSIGN (parser_state);
 131
 132   /* Begin counting arguments for a function call,
 133      saving the data about any containing call.  */
 134
 135   void start_arglist ()
 136   {
 137     m_funcall_chain.push_back (arglist_len);
 138     arglist_len = 0;
 139   }
 140
 141   /* Return the number of arguments in a function call just terminated,
 142      and restore the data for the containing function call.  */
 143
 144   int end_arglist ()
 145   {
 146     int val = arglist_len;
 147     arglist_len = m_funcall_chain.back ();
 148     m_funcall_chain.pop_back ();
 149     return val;
 150   }
 151
 152   /* Mark the given operation as the starting location of a structure
 153      expression.  This is used when completing on field names.  */
 154
 155   void mark_struct_expression (expr::structop_base_operation *op);
 156
 157   /* Indicate that the current parser invocation is completing a tag.
 158      TAG is the type code of the tag, and PTR and LENGTH represent the
 159      start of the tag name.  */
 160
 161   void mark_completion_tag (enum type_code tag, const char *ptr, int length);
 162
 163   /* Push an operation on the stack.  */
 164   void push (expr::operation_up &&op)
 165   {
 166     m_operations.push_back (std::move (op));
 167   }
 168
 169   /* Create a new operation and push it on the stack.  */
 170   template<typename T, typename... Arg>
 171   void push_new (Arg... args)
 172   {
 173     m_operations.emplace_back (new T (std::forward<Arg> (args)...));
 174   }
 175
 176   /* Push a new C string operation.  */
 177   void push_c_string (int, struct stoken_vector *vec);
 178
 179   /* Push a symbol reference.  If SYM is nullptr, look for a minimal
 180      symbol.  */
 181   void push_symbol (const char *name, block_symbol sym);
 182
 183   /* Push a reference to $mumble.  This may result in a convenience
 184      variable, a history reference, or a register.  */
 185   void push_dollar (struct stoken str);
 186
 187   /* Pop an operation from the stack.  */
 188   expr::operation_up pop ()
 189   {
 190     expr::operation_up result = std::move (m_operations.back ());
 191     m_operations.pop_back ();
 192     return result;
 193   }
 194
 195   /* Pop N elements from the stack and return a vector.  */
 196   std::vector<expr::operation_up> pop_vector (int n)
 197   {
 198     std::vector<expr::operation_up> result (n);
 199     for (int i = 1; i <= n; ++i)
 200       result[n - i] = pop ();
 201     return result;
 202   }
 203
 204   /* A helper that pops an operation, wraps it in some other
 205      operation, and pushes it again.  */
 206   template<typename T>
 207   void wrap ()
 208   {
 209     using namespace expr;
 210     operation_up v = ::expr::make_operation<T> (pop ());
 211     push (std::move (v));
 212   }
 213
 214   /* A helper that pops two operations, wraps them in some other
 215      operation, and pushes the result.  */
 216   template<typename T>
 217   void wrap2 ()
 218   {
 219     expr::operation_up rhs = pop ();
 220     expr::operation_up lhs = pop ();
 221     push (expr::make_operation<T> (std::move (lhs), std::move (rhs)));
 222   }
 223
 224   /* If this is nonzero, this block is used as the lexical context for
 225      symbol names.  */
 226
 227   const struct block * const expression_context_block;
 228
 229   /* If expression_context_block is non-zero, then this is the PC
 230      within the block that we want to evaluate expressions at.  When
 231      debugging C or C++ code, we use this to find the exact line we're
 232      at, and then look up the macro definitions active at that
 233      point.  */
 234   const CORE_ADDR expression_context_pc;
 235
 236   /* Nonzero means stop parsing on first comma (if not within parentheses).  */
 237
 238   int comma_terminates;
 239
 240   /* During parsing of a C expression, the pointer to the next character
 241      is in this variable.  */
 242
 243   const char *lexptr;
 244
 245   /* After a token has been recognized, this variable points to it.
 246      Currently used only for error reporting.  */
 247   const char *prev_lexptr = nullptr;
 248
 249   /* Number of arguments seen so far in innermost function call.  */
 250
 251   int arglist_len = 0;
 252
 253   /* True if parsing an expression to attempt completion.  */
 254   bool parse_completion;
 255
 256   /* Completion state is updated here.  */
 257   expr_completion_state m_completion_state;
 258
 259   /* The innermost block tracker.  */
 260   innermost_block_tracker *block_tracker;
 261
 262   /* True if no value is expected from the expression.  */
 263   bool void_context_p;
 264
 265 private:
 266
 267   /* Data structure for saving values of arglist_len for function calls whose
 268      arguments contain other function calls.  */
 269
 270   std::vector<int> m_funcall_chain;
 271
 272   /* Stack of operations.  */
 273   std::vector<expr::operation_up> m_operations;
 274 };
 275
 276 /* When parsing expressions we track the innermost block that was
 277    referenced.  */
 278
 279 class innermost_block_tracker
 280 {
 281 public:
 282   innermost_block_tracker (innermost_block_tracker_types types
 283                            = INNERMOST_BLOCK_FOR_SYMBOLS)
 284     : m_types (types),
 285       m_innermost_block (NULL)
 286   { /* Nothing.  */ }
 287
 288   /* Update the stored innermost block if the new block B is more inner
 289      than the currently stored block, or if no block is stored yet.  The
 290      type T tells us whether the block B was for a symbol or for a
 291      register.  The stored innermost block is only updated if the type T is
 292      a type we are interested in, the types we are interested in are held
 293      in M_TYPES and set during RESET.  */
 294   void update (const struct block *b, innermost_block_tracker_types t);
 295
 296   /* Overload of main UPDATE method which extracts the block from BS.  */
 297   void update (const struct block_symbol &bs)
 298   {
 299     update (bs.block, INNERMOST_BLOCK_FOR_SYMBOLS);
 300   }
 301
 302   /* Return the stored innermost block.  Can be nullptr if no symbols or
 303      registers were found during an expression parse, and so no innermost
 304      block was defined.  */
 305   const struct block *block () const
 306   {
 307     return m_innermost_block;
 308   }
 309
 310 private:
 311   /* The type of innermost block being looked for.  */
 312   innermost_block_tracker_types m_types;
 313
 314   /* The currently stored innermost block found while parsing an
 315      expression.  */
 316   const struct block *m_innermost_block;
 317 };
 318
 319 /* A string token, either a char-string or bit-string.  Char-strings are
 320    used, for example, for the names of symbols.  */
 321
 322 struct stoken
 323   {
 324     /* Pointer to first byte of char-string or first bit of bit-string.  */
 325     const char *ptr;
 326     /* Length of string in bytes for char-string or bits for bit-string.  */
 327     int length;
 328   };
 329
 330 struct typed_stoken
 331   {
 332     /* A language-specific type field.  */
 333     int type;
 334     /* Pointer to first byte of char-string or first bit of bit-string.  */
 335     char *ptr;
 336     /* Length of string in bytes for char-string or bits for bit-string.  */
 337     int length;
 338   };
 339
 340 struct stoken_vector
 341   {
 342     int len;
 343     struct typed_stoken *tokens;
 344   };
 345
 346 struct ttype
 347   {
 348     struct stoken stoken;
 349     struct type *type;
 350   };
 351
 352 struct symtoken
 353   {
 354     struct stoken stoken;
 355     struct block_symbol sym;
 356     int is_a_field_of_this;
 357   };
 358
 359 struct objc_class_str
 360   {
 361     struct stoken stoken;
 362     struct type *type;
 363     int theclass;
 364   };
 365
 366 extern const char *find_template_name_end (const char *);
 367
 368 extern std::string copy_name (struct stoken);
 369
 370 extern bool parse_float (const char *p, int len,
 371                          const struct type *type, gdb_byte *data);
 372 \f
 373
 374 /* Function used to avoid direct calls to fprintf
 375    in the code generated by the bison parser.  */
 376
 377 extern void parser_fprintf (FILE *, const char *, ...) ATTRIBUTE_PRINTF (2, 3);
 378
 379 extern bool exp_uses_objfile (struct expression *exp, struct objfile *objfile);
 380
 381 #endif /* PARSER_DEFS_H */
 382