1 /* Interface between GCC C++ FE and GDB
2 
3    Copyright (C) 2014-2020 Free Software Foundation, Inc.
4 
5    This file is part of GCC.
6 
7    This program is free software; you can redistribute it and/or modify
8    it under the terms of the GNU General Public License as published by
9    the Free Software Foundation; either version 3 of the License, or
10    (at your option) any later version.
11 
12    This program is distributed in the hope that it will be useful,
13    but WITHOUT ANY WARRANTY; without even the implied warranty of
14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15    GNU General Public License for more details.
16 
17    You should have received a copy of the GNU General Public License
18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
19 
20 #ifndef GCC_CP_INTERFACE_H
21 #define GCC_CP_INTERFACE_H
22 
23 #include "gcc-interface.h"
24 
25 /* This header defines the interface to the GCC API.  It must be both
26    valid C and valid C++, because it is included by both programs.  */
27 
28 #ifdef __cplusplus
29 extern "C" {
30 #endif
31 
32 /* Forward declaration.  */
33 
34 struct gcc_cp_context;
35 
36 /*
37  * Definitions and declarations for the C++ front end.
38  */
39 
40 /* Defined versions of the C++ front-end API.  */
41 
42 enum gcc_cp_api_version
43 {
44   GCC_CP_FE_VERSION_0 = 0
45 };
46 
47 /* Qualifiers.  */
48 
49 enum gcc_cp_qualifiers
50 {
51   GCC_CP_QUALIFIER_CONST = 1,
52   GCC_CP_QUALIFIER_VOLATILE = 2,
53   GCC_CP_QUALIFIER_RESTRICT = 4
54 };
55 
56 /* Ref qualifiers.  */
57 
58 enum gcc_cp_ref_qualifiers {
59   GCC_CP_REF_QUAL_NONE = 0,
60   GCC_CP_REF_QUAL_LVALUE = 1,
61   GCC_CP_REF_QUAL_RVALUE = 2
62 };
63 
64 /* Opaque typedef for unbound class templates.  They are used for
65    template arguments, and defaults for template template
66    parameters.  */
67 
68 typedef unsigned long long gcc_utempl;
69 
70 /* Opaque typedef for expressions.  They are used for template
71    arguments, defaults for non-type template parameters, and defaults
72    for function arguments.  */
73 
74 typedef unsigned long long gcc_expr;
75 
76 typedef enum
77   { GCC_CP_TPARG_VALUE, GCC_CP_TPARG_CLASS,
78     GCC_CP_TPARG_TEMPL, GCC_CP_TPARG_PACK }
79 gcc_cp_template_arg_kind;
80 
81 typedef union
82 { gcc_expr value; gcc_type type; gcc_utempl templ; gcc_type pack; }
83 gcc_cp_template_arg;
84 
85 /* An array of template arguments.  */
86 
87 struct gcc_cp_template_args
88 {
89   /* Number of elements.  */
90 
91   int n_elements;
92 
93   /* kind[i] indicates what kind of template argument type[i] is.  */
94 
95   char /* gcc_cp_template_arg_kind */ *kinds;
96 
97   /* The template arguments.  */
98 
99   gcc_cp_template_arg *elements;
100 };
101 
102 /* An array of (default) function arguments.  */
103 
104 struct gcc_cp_function_args
105 {
106   /* Number of elements.  */
107 
108   int n_elements;
109 
110   /* The (default) values for each argument.  */
111 
112   gcc_expr *elements;
113 };
114 
115 /* This enumerates the kinds of decls that GDB can create.  */
116 
117 enum gcc_cp_symbol_kind
118 {
119   /* A function.  */
120 
121   GCC_CP_SYMBOL_FUNCTION,
122 
123   /* A variable.  */
124 
125   GCC_CP_SYMBOL_VARIABLE,
126 
127   /* A typedef, or an alias declaration (including template ones).  */
128 
129   GCC_CP_SYMBOL_TYPEDEF,
130 
131   /* A label.  */
132 
133   GCC_CP_SYMBOL_LABEL,
134 
135   /* A class, forward declared in build_decl (to be later defined in
136      start_class_definition), or, in a template parameter list scope,
137      a declaration of a template class, closing the parameter
138      list.  */
139 
140   GCC_CP_SYMBOL_CLASS,
141 
142   /* A union, forward declared in build_decl (to be later defined in
143      start_class_definition).  */
144 
145   GCC_CP_SYMBOL_UNION,
146 
147   /* An enumeration type being introduced with start_new_enum_type.  */
148 
149   GCC_CP_SYMBOL_ENUM,
150 
151   /* A nonstatic data member being introduced with new_field.  */
152 
153   GCC_CP_SYMBOL_FIELD,
154 
155   /* A base class in a gcc_vbase_array.  */
156 
157   GCC_CP_SYMBOL_BASECLASS,
158 
159   /* A using declaration in new_using_decl.  */
160 
161   GCC_CP_SYMBOL_USING,
162 
163   /* A (lambda) closure class type.  In many regards this is just like
164      a regular class, but it's not supposed to have base classes, some
165      of the member functions that are usually implicitly-defined are
166      deleted, and it should have an operator() member function that
167      holds the lambda body.  We can't instantiate objects of lambda
168      types from the snippet, but we can interact with them in such
169      ways as passing them to functions that take their types, and
170      calling their body.  */
171 
172   GCC_CP_SYMBOL_LAMBDA_CLOSURE,
173 
174   /* Marker to check that we haven't exceeded GCC_CP_SYMBOL_MASK.  */
175   GCC_CP_SYMBOL_END,
176 
177   GCC_CP_SYMBOL_MASK = 15,
178 
179   /* When defining a class member, at least one of the
180      GCC_CP_ACCESS_MASK bits must be set; when defining a namespace-
181      or union-scoped symbol, none of them must be set.  */
182 
183   GCC_CP_ACCESS_PRIVATE,
184   GCC_CP_ACCESS_PUBLIC = GCC_CP_ACCESS_PRIVATE << 1,
185   GCC_CP_ACCESS_MASK = (GCC_CP_ACCESS_PUBLIC
186 			       | GCC_CP_ACCESS_PRIVATE),
187   GCC_CP_ACCESS_PROTECTED = GCC_CP_ACCESS_MASK,
188   GCC_CP_ACCESS_NONE = 0,
189 
190   GCC_CP_FLAG_BASE = GCC_CP_ACCESS_PRIVATE << 2,
191 
192   /* Flags to be used along with GCC_CP_SYMBOL_FUNCTION:  */
193 
194   /* This flag should be set for constructors, destructors and
195      operators.  */
196   GCC_CP_FLAG_SPECIAL_FUNCTION = GCC_CP_FLAG_BASE,
197 
198   /* We intentionally cannot express inline, constexpr, or virtual
199      override for functions.  We can't inline or constexpr-replace
200      without a source-level body.  The override keyword is only
201      meaningful within the definition of the containing class.  */
202 
203   /* This indicates a "virtual" member function, explicitly or
204      implicitly (due to a virtual function with the same name and
205      prototype in a base class) declared as such.  */
206   GCC_CP_FLAG_VIRTUAL_FUNCTION = GCC_CP_FLAG_BASE << 1,
207 
208   /* The following two flags should only be set when the flag above is
209      set.  */
210 
211   /* This indicates a pure virtual member function, i.e., one that is
212      declared with "= 0", even if a body is provided in the
213      definition.  */
214   GCC_CP_FLAG_PURE_VIRTUAL_FUNCTION = GCC_CP_FLAG_BASE << 2,
215 
216   /* This indicates a "final" virtual member function.  */
217   GCC_CP_FLAG_FINAL_VIRTUAL_FUNCTION = GCC_CP_FLAG_BASE << 3,
218 
219   /* This indicates a special member function should have its default
220      implementation.  This either means the function declaration
221      contains the "= default" tokens, or that the member function was
222      implicitly generated by the compiler, although the latter use is
223      discouraged: just let the compiler implicitly introduce it.
224 
225      A member function defaulted after its first declaration has
226      slightly different ABI implications from one implicitly generated
227      or explicitly defaulted at the declaration (and definition)
228      point.  To avoid silent (possibly harmless) violation of the one
229      definition rule, it is recommended that this flag not be used for
230      such functions, and that the address of the definition be
231      supplied instead.  */
232   GCC_CP_FLAG_DEFAULTED_FUNCTION = GCC_CP_FLAG_BASE << 4,
233 
234   /* This indicates a deleted member function, i.e., one that has been
235      defined as "= delete" at its declaration point, or one that has
236      been implicitly defined as deleted (with or without an explicit
237      "= default" definition).
238 
239      This should not be used for implicitly-declared member functions
240      that resolve to deleted definitions, as it may affect the
241      implicit declaration of other member functions.  */
242   GCC_CP_FLAG_DELETED_FUNCTION = GCC_CP_FLAG_BASE << 5,
243 
244   /* This indicates a constructor or type-conversion operator declared
245      as "explicit".  */
246 
247   GCC_CP_FLAG_EXPLICIT_FUNCTION = GCC_CP_FLAG_BASE << 6,
248 
249   GCC_CP_FLAG_END_FUNCTION,
250   GCC_CP_FLAG_MASK_FUNCTION = (((GCC_CP_FLAG_END_FUNCTION - 1) << 1)
251 			       - GCC_CP_FLAG_BASE),
252 
253   /* Flags to be used along with GCC_CP_SYMBOL_VARIABLE:  */
254 
255   /* This indicates a variable declared as "constexpr".  */
256 
257   GCC_CP_FLAG_CONSTEXPR_VARIABLE = GCC_CP_FLAG_BASE,
258 
259   /* This indicates a variable declared as "thread_local".  ??? What
260      should the ADDRESS be?  */
261 
262   GCC_CP_FLAG_THREAD_LOCAL_VARIABLE = GCC_CP_FLAG_BASE << 1,
263 
264   GCC_CP_FLAG_END_VARIABLE,
265   GCC_CP_FLAG_MASK_VARIABLE = (((GCC_CP_FLAG_END_VARIABLE - 1) << 1)
266 			       - GCC_CP_FLAG_BASE),
267 
268   /* Flags to be used when defining nonstatic data members of classes
269      with new_field.  */
270 
271   /* Use this when no flags are present.  */
272   GCC_CP_FLAG_FIELD_NOFLAG = 0,
273 
274   /* This indicates the field is declared as mutable.  */
275   GCC_CP_FLAG_FIELD_MUTABLE = GCC_CP_FLAG_BASE,
276 
277   GCC_CP_FLAG_END_FIELD,
278   GCC_CP_FLAG_MASK_FIELD = (((GCC_CP_FLAG_END_FIELD - 1) << 1)
279 			    - GCC_CP_FLAG_BASE),
280 
281   /* Flags to be used when defining an enum with
282      start_new_enum_type.  */
283 
284   /* This indicates an enum type without any flags.  */
285   GCC_CP_FLAG_ENUM_NOFLAG = 0,
286 
287   /* This indicates a scoped enum type.  */
288   GCC_CP_FLAG_ENUM_SCOPED = GCC_CP_FLAG_BASE,
289 
290   GCC_CP_FLAG_END_ENUM,
291   GCC_CP_FLAG_MASK_ENUM = (((GCC_CP_FLAG_END_ENUM - 1) << 1)
292 			       - GCC_CP_FLAG_BASE),
293 
294 
295   /* Flags to be used when introducing a class or a class template
296      with build_decl.  */
297 
298   /* This indicates an enum type without any flags.  */
299   GCC_CP_FLAG_CLASS_NOFLAG = 0,
300 
301   /* This indicates the class is actually a struct.  This has no
302      effect whatsoever on access control in this interface, since all
303      class members must have explicit access control bits set, but it
304      may affect error messages.  */
305   GCC_CP_FLAG_CLASS_IS_STRUCT = GCC_CP_FLAG_BASE,
306 
307   GCC_CP_FLAG_END_CLASS,
308   GCC_CP_FLAG_MASK_CLASS = (((GCC_CP_FLAG_END_CLASS - 1) << 1)
309 			       - GCC_CP_FLAG_BASE),
310 
311 
312   /* Flags to be used when introducing a virtual base class in a
313      gcc_vbase_array.  */
314 
315   /* This indicates an enum type without any flags.  */
316   GCC_CP_FLAG_BASECLASS_NOFLAG = 0,
317 
318   /* This indicates the class is actually a struct.  This has no
319      effect whatsoever on access control in this interface, since all
320      class members must have explicit access control bits set, but it
321      may affect error messages.  */
322   GCC_CP_FLAG_BASECLASS_VIRTUAL = GCC_CP_FLAG_BASE,
323 
324   GCC_CP_FLAG_END_BASECLASS,
325   GCC_CP_FLAG_MASK_BASECLASS = (((GCC_CP_FLAG_END_BASECLASS - 1) << 1)
326 				- GCC_CP_FLAG_BASE),
327 
328 
329   GCC_CP_FLAG_MASK = (GCC_CP_FLAG_MASK_FUNCTION
330 		      | GCC_CP_FLAG_MASK_VARIABLE
331 		      | GCC_CP_FLAG_MASK_FIELD
332 		      | GCC_CP_FLAG_MASK_ENUM
333 		      | GCC_CP_FLAG_MASK_CLASS
334 		      | GCC_CP_FLAG_MASK_BASECLASS
335 		      )
336 };
337 
338 
339 /* An array of types used for creating lists of base classes.  */
340 
341 struct gcc_vbase_array
342 {
343   /* Number of elements.  */
344 
345   int n_elements;
346 
347   /* The base classes.  */
348 
349   gcc_type *elements;
350 
351   /* Flags for each base class.  Used to indicate access control and
352      virtualness.  */
353 
354   enum gcc_cp_symbol_kind *flags;
355 };
356 
357 
358 /* This enumerates the types of symbols that GCC might request from
359    GDB.  */
360 
361 enum gcc_cp_oracle_request
362 {
363   /* An identifier in namespace scope -- type, variable, function,
364      namespace, template.  All namespace-scoped symbols with the
365      requested name, in any namespace (including the global
366      namespace), should be defined in response to this request.  */
367 
368   GCC_CP_ORACLE_IDENTIFIER
369 };
370 
371 /* The type of the function called by GCC to ask GDB for a symbol's
372    definition.  DATUM is an arbitrary value supplied when the oracle
373    function is registered.  CONTEXT is the GCC context in which the
374    request is being made.  REQUEST specifies what sort of symbol is
375    being requested, and IDENTIFIER is the name of the symbol.  */
376 
377 typedef void gcc_cp_oracle_function (void *datum,
378 				     struct gcc_cp_context *context,
379 				     enum gcc_cp_oracle_request request,
380 				     const char *identifier);
381 
382 /* The type of the function called by GCC to ask GDB for a symbol's
383    address.  This should return 0 if the address is not known.  */
384 
385 typedef gcc_address gcc_cp_symbol_address_function (void *datum,
386 						    struct gcc_cp_context *ctxt,
387 						    const char *identifier);
388 
389 /* The type of the function called by GCC to ask GDB to enter or leave
390    the user expression scope.  */
391 
392 typedef void gcc_cp_enter_leave_user_expr_scope_function (void *datum,
393 							  struct gcc_cp_context
394 							  *context);
395 
396 /* The vtable used by the C front end.  */
397 
398 struct gcc_cp_fe_vtable
399 {
400   /* The version of the C interface.  The value is one of the
401      gcc_cp_api_version constants.  */
402 
403   unsigned int cp_version;
404 
405   /* Set the callbacks for this context.
406 
407      The binding oracle is called whenever the C++ parser needs to
408      look up a symbol.  This gives the caller a chance to lazily
409      instantiate symbols using other parts of the gcc_cp_fe_interface
410      API.  The symbol is looked up without a scope, and the oracle
411      must supply a definition for ALL namespace-scoped definitions
412      bound to the symbol.
413 
414      The address oracle is called whenever the C++ parser needs to
415      look up a symbol.  This may be called for symbols not provided by
416      the symbol oracle, such as built-in functions where GCC provides
417      the declaration; other internal symbols, such as those related
418      with thunks, rtti, and virtual tables are likely to be queried
419      through this interface too.  The identifier is a mangled symbol
420      name.
421 
422      DATUM is an arbitrary piece of data that is passed back verbatim
423      to the callbacks in requests.  */
424 
425   void (*set_callbacks) (struct gcc_cp_context *self,
426 			 gcc_cp_oracle_function *binding_oracle,
427 			 gcc_cp_symbol_address_function *address_oracle,
428 			 gcc_cp_enter_leave_user_expr_scope_function *enter_scope,
429 			 gcc_cp_enter_leave_user_expr_scope_function *leave_scope,
430 			 void *datum);
431 
432 #define GCC_METHOD0(R, N) \
433   R (*N) (struct gcc_cp_context *);
434 #define GCC_METHOD1(R, N, A) \
435   R (*N) (struct gcc_cp_context *, A);
436 #define GCC_METHOD2(R, N, A, B) \
437   R (*N) (struct gcc_cp_context *, A, B);
438 #define GCC_METHOD3(R, N, A, B, C) \
439   R (*N) (struct gcc_cp_context *, A, B, C);
440 #define GCC_METHOD4(R, N, A, B, C, D) \
441   R (*N) (struct gcc_cp_context *, A, B, C, D);
442 #define GCC_METHOD5(R, N, A, B, C, D, E) \
443   R (*N) (struct gcc_cp_context *, A, B, C, D, E);
444 #define GCC_METHOD7(R, N, A, B, C, D, E, F, G) \
445   R (*N) (struct gcc_cp_context *, A, B, C, D, E, F, G);
446 
447 #include "gcc-cp-fe.def"
448 
449 #undef GCC_METHOD0
450 #undef GCC_METHOD1
451 #undef GCC_METHOD2
452 #undef GCC_METHOD3
453 #undef GCC_METHOD4
454 #undef GCC_METHOD5
455 #undef GCC_METHOD7
456 
457 };
458 
459 /* The C front end object.  */
460 
461 struct gcc_cp_context
462 {
463   /* Base class.  */
464 
465   struct gcc_base_context base;
466 
467   /* Our vtable.  This is a separate field because this is simpler
468      than implementing a vtable inheritance scheme in C.  */
469 
470   const struct gcc_cp_fe_vtable *cp_ops;
471 };
472 
473 /* The name of the .so that the compiler builds.  We dlopen this
474    later.  */
475 
476 #define GCC_CP_FE_LIBCC libcc1.so
477 
478 /* The compiler exports a single initialization function.  This macro
479    holds its name as a symbol.  */
480 
481 #define GCC_CP_FE_CONTEXT gcc_cp_fe_context
482 
483 /* The type of the initialization function.  The caller passes in the
484    desired base version and desired C-specific version.  If the
485    request can be satisfied, a compatible gcc_context object will be
486    returned.  Otherwise, the function returns NULL.  */
487 
488 typedef struct gcc_cp_context *gcc_cp_fe_context_function
489     (enum gcc_base_api_version,
490      enum gcc_cp_api_version);
491 
492 #ifdef __cplusplus
493 }
494 #endif
495 
496 #endif /* GCC_CP_INTERFACE_H */
497