1/* Interface between GCC C++ FE and GDB  -*- c -*-
2
3   Copyright (C) 2014-2018 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
21
22/* Push namespace NAME as the current binding level, to which
23   newly-introduced decls will be bound.  An empty string identifies
24   the global namespace, whereas NULL identifies an anonymous
25   namespace.  A namespace named NAME is created in the current scope,
26   if needed.
27
28   If the newly-created namespace is to be an inline namespace, see
29   make_namespace_inline.  */
30
31GCC_METHOD1 (int /* bool */, push_namespace,
32	     const char *)	      /* Argument NAME.  */
33
34/* Push TYPE as the current binding level, making its members visible
35   for name lookup.  The current scope before the call must be the
36   scope in which the class was declared.  This should be used if the
37   definition of a class is already finished, but one wishes to define
38   a nested class, or to enter the scope of one of its member
39   functions.  */
40
41GCC_METHOD1 (int /* bool */, push_class,
42	     gcc_type)		/* Argument TYPE.  */
43
44/* Push FUNCTION_DECL as the current (empty) binding level (see
45   reactivate_decl).  The current enclosing scope before the call must
46   be the scope in which the function was declared.  */
47
48GCC_METHOD1 (int /* bool */, push_function,
49	     gcc_decl)	     /* Argument FUNCTION_DECL.  */
50
51/* Make DECL visible (again?) within SCOPE.  When SCOPE is NULL, it
52   means the current scope; if it is not NULL, it must name a function
53   that is currently active, even if not at the top of the binding
54   chain.
55
56   This function can be used to make e.g. a global function or
57   variable visible in a namespace or local scope (overriding another
58   enclosing definition of the same name), but its most common
59   expected use of this primitive, that gives it its name, is to make
60   declarations visible again after reentering a function scope,
61   because when a function is entered with push_function, that does
62   NOT make any of the declarations nested in it visible for name
63   lookup.
64
65   There is a reason/excuse for that: unlike namespaces and classes,
66   G++ doesn't ever have to reenter function scopes, so its name
67   resolution infrastructure is not prepared to do that.  But wait,
68   there is also a good use for this apparent limitation: a function
69   may contain multiple scopes (blocks), and the name may be bound to
70   different symbols in each of these scopes.  With this interface, as
71   we reenter a function scope, we may choose which symbols to make
72   visible for the code snippet, or, if there could be template
73   functions in local scopes, for unresolved names in nested template
74   class default arguments, or in nested template function signatures.
75
76   As for making a local declaration visible for the code snippet,
77   there are two possibilities: a) introduce it upfront, while
78   entering the scope for the user expression (see the enter_scope
79   callback, called by g++ when encountering the push_user_expression
80   pragma), which might save some scope switching and reactivate_decl
81   (though this can't be helped if some declarations have to be
82   introduced and discarded, because of multiple definitions of the
83   same name in different scopes within a function: they have to be
84   defined in discriminator order); or b) introduce it when its name
85   is looked up, entering the scope, introducing the declaration,
86   leaving the scope, and then reactivating the declaration in its
87   local scope.
88
89   Here's some more detail on how reactivate_decl works.  Say there's
90   a function foo whose body looks like this:
91
92   {
93     {
94// point 1
95       class c {} o __attribute__ ((__used__)); // c  , o
96     }
97     struct c {
98       void f() {
99// point 2
100       }
101     } o __attribute__ ((__used__));            // c_0, o_0
102     {
103       class c {} p __attribute__ ((__used__)); // c_1, p
104// point 3
105       o.f();
106     }
107   }
108
109   When we are about to define class c at point 1, we enter the
110   function foo scope, and since no symbols are visible at point 1, we
111   proceed to declare class c.  We may then define the class right
112   away, or, if we leave the function scope, and we later wish to
113   define it, or to define object o, we can reenter the scope and just
114   use the previously-obtained gcc_decl to define the class, without
115   having to reactivate the declaration.
116
117   Now, if we are to set up the binding context for point 2, we have
118   to define c_0::f, and in order to do so, we have to declare and
119   define c_0.  Before we can declare c_0, we MUST at least declare c.
120
121     As a general rule, before we can declare or define any local name
122     with a discriminator, we have to at least declare any other
123     occurrences of the same name in the same enclosing entity with
124     lower or absent discriminator.
125
126   So, we declare c, then we leave the function scope and reenter it
127   so as to declare c_0 (also with name "c", which is why we have to
128   leave and reenter the function scope, otherwise we would get an
129   error because of the duplicate definition; g++ will assign a
130   discriminator because it still remembers there was an earlier
131   declaration of c_0 within the function, it's just no longer in
132   scope), then we can define c_0, including its member function f.
133
134   Likewise, if we wish to define o_0, we have to define o first.  If
135   we wish to declare (and maybe then define) c_1, we have to at least
136   declare (c and then) c_0 first.
137
138   Then, as we set up the binding context to compile a code snippet at
139   point 3, we may choose to activate c_1, o_0 and p upfront,
140   declaring and discarding c, c_0 and o, and then reentering the
141   funciton scope to declare c_1, o_0 and p; or we can wait for oracle
142   lookups of c, o or p.  If c is looked up, and the debugger resolves
143   c in the scope to c_1, it is expected to enter the function scope
144   from the top level, declare c, leave it, reenter it, declare c_0,
145   leave it, reenter it, declare c_1, leave it, and then reactivate
146   c_1 in the function scope.  If c_1 is needed as a complete type,
147   the definition may be given right after the declaration, or the
148   scope will have to be reentered in order to define the class.
149
150.  If the code snippet is at point 2, we don't need to (re)activate
151   any declaration: nothing from any local scope is visible.  Just
152   entering the scope of the class containing member function f
153   reactivates the names of its members, including the class name
154   itself.  */
155
156GCC_METHOD2 (int /* bool */, reactivate_decl,
157	     gcc_decl,		/* Argument DECL.  */
158	     gcc_decl)		/* Argument SCOPE.  */
159
160/* Pop the namespace last entered with push_namespace, or class last
161   entered with push_class, or function last entered with
162   push_function, restoring the binding level in effect before the
163   matching push_* call.  */
164
165GCC_METHOD0 (int /* bool */, pop_binding_level)
166
167/* Return the NAMESPACE_DECL, TYPE_DECL or FUNCTION_DECL of the
168   binding level that would be popped by pop_scope.  */
169
170GCC_METHOD0 (gcc_decl, get_current_binding_level_decl)
171
172/* Make the current binding level an inline namespace.  It must be a
173   namespace to begin with.  It is safe to call this more than once
174   for the same namespace, but after the first call, subsequent ones
175   will not return a success status.  */
176
177GCC_METHOD0 (int /* bool */, make_namespace_inline)
178
179/* Add USED_NS to the namespaces used by the current binding level.
180   Use get_current_binding_level_decl to obtain USED_NS's
181   gcc_decl.  */
182
183GCC_METHOD1 (int /* bool */, add_using_namespace,
184	     gcc_decl)			/* Argument USED_NS.  */
185
186/* Introduce a namespace alias declaration, as in:
187
188   namespace foo = [... ::] bar;
189
190   After this call, namespace TARGET will be visible as ALIAS within
191   the current namespace.  Get the declaration for TARGET by calling
192   get_current_binding_level_decl after pushing into it.  */
193
194GCC_METHOD2 (int /* bool */, add_namespace_alias,
195	     const char *,		/* Argument ALIAS.  */
196	     gcc_decl)			/* Argument TARGET.  */
197
198/* Introduce a using declaration, as in:
199
200   using foo::bar;
201
202   The TARGET decl names the qualifying scope (foo:: above) and the
203   identifier (bar), but that does not mean that only TARGET will be
204   brought into the current scope: all bindings of TARGET's identifier
205   in the qualifying scope will be brought in.
206
207   FLAGS should specify GCC_CP_SYMBOL_USING.  If the current scope is
208   a class scope, visibility flags must be supplied.
209
210   Even when TARGET is template dependent, we don't need to specify
211   whether or not it is a typename: the supplied declaration (that
212   could be a template-dependent type converted to declaration by
213   get_type_decl) indicates so.  */
214
215GCC_METHOD2 (int /* bool */, add_using_decl,
216	     enum gcc_cp_symbol_kind, /* Argument FLAGS.  */
217	     gcc_decl)		      /* Argument TARGET.  */
218
219/* Create a new "decl" in GCC, and bind it in the current binding
220   level.  A decl is a declaration, basically a kind of symbol.
221
222   NAME is the name of the new symbol.  SYM_KIND is the kind of
223   symbol being requested.  SYM_TYPE is the new symbol's C++ type;
224   except for labels, where this is not meaningful and should be
225   zero.  If SUBSTITUTION_NAME is not NULL, then a reference to this
226   decl in the source will later be substituted with a dereference
227   of a variable of the given name.  Otherwise, for symbols having
228   an address (e.g., functions), ADDRESS is the address.  FILENAME
229   and LINE_NUMBER refer to the symbol's source location.  If this
230   is not known, FILENAME can be NULL and LINE_NUMBER can be 0.
231   This function returns the new decl.
232
233   Use this function to register typedefs, functions and variables to
234   namespace and local binding levels, and typedefs, member functions
235   (static or not), and static data members to class binding levels.
236   Class members must have their access controls specified with
237   GCC_CP_ACCESS_* flags in SYM_KIND.
238
239   Note that, since access controls are disabled, we have no means to
240   express private, protected and public.
241
242   There are various flags that can be set in SYM_KIND to specify
243   additional semantics.  Look for GCC_CP_FLAGs in the definition of
244   enum gcc_cp_symbol_kind in gcc-cp-interface.h.
245
246   In order to define member functions, pass GCC_CP_SYMBOL_FUNCTION in
247   SYM_KIND, and a function_type for static member functions or a
248   method type for non-static member functions, including constructors
249   and destructors.  Use build_function_type to create a function
250   type; for a method type, start by creating a function type without
251   any compiler-introduced artificial arguments (the implicit this
252   pointer, and the __in_chrg added to constructors and destructors,
253   and __vtt_parm added to the former), and then use build_method_type
254   to create the method type out of the class type and the function
255   type.
256
257   For operator functions, set GCC_CP_FLAG_SPECIAL_FUNCTION in
258   SYM_KIND, in addition to any other applicable flags, and pass as
259   NAME a string starting with the two-character mangling for operator
260   name: "ps" for unary plus, "mL" for multiply and assign, *=; etc.
261   Use "cv" for type converstion operators (the target type portion
262   may be omitted, as it is taken from the return type in SYM_TYPE).
263   For operator"", use "li" followed by the identifier (the mangled
264   name mandates digits specifying the length of the identifier; if
265   present, they determine the end of the identifier, otherwise, the
266   identifier extents to the end of the string, so that "li3_Kme" and
267   "li_Km" are equivalent).
268
269   Constructors and destructors need special care, because for each
270   constructor and destructor there may be multiple clones defined
271   internally by the compiler.  With build_decl, you can introduce the
272   base declaration of a constructor or a destructor, setting
273   GCC_CP_FLAG_SPECIAL_FUNCTION the flag and using names starting with
274   capital "C" or "D", respectively, followed by a digit (see below),
275   a blank, or NUL ('\0').  DO NOT supply an ADDRESS or a
276   SUBSTITUTION_NAME to build_decl, it would be meaningless (and
277   rejected) for the base declaration; use define_cdtor_clone to
278   introduce the address of each clone.  For constructor templates,
279   declare the template with build_decl, and then, for each
280   specialization, introduce it with
281   build_function_template_specialization, and then define the
282   addresses of each of its clones with define_cdtor_clone.
283
284   NAMEs for GCC_CP_FLAG_SPECIAL_FUNCTION:
285
286     NAME    meaning
287     C?      constructor base declaration (? may be 1, 2, 4, blank or NUL)
288     D?      destructor base declaration (? may be 0, 1, 2, 4, blank or NUL)
289     nw      operator new
290     na      operator new[]
291     dl      operator delete
292     da      operator delete[]
293     ps      operator + (unary)
294     ng      operator - (unary)
295     ad      operator & (unary)
296     de      operator * (unary)
297     co      operator ~
298     pl      operator +
299     mi      operator -
300     ml      operator *
301     dv      operator /
302     rm      operator %
303     an      operator &
304     or      operator |
305     eo      operator ^
306     aS      operator =
307     pL      operator +=
308     mI      operator -=
309     mL      operator *=
310     dV      operator /=
311     rM      operator %=
312     aN      operator &=
313     oR      operator |=
314     eO      operator ^=
315     ls      operator <<
316     rs      operator >>
317     lS      operator <<=
318     rS      operator >>=
319     eq      operator ==
320     ne      operator !=
321     lt      operator <
322     gt      operator >
323     le      operator <=
324     ge      operator >=
325     nt      operator !
326     aa      operator &&
327     oo      operator ||
328     pp      operator ++
329     mm      operator --
330     cm      operator ,
331     pm      operator ->*
332     pt      operator ->
333     cl      operator ()
334     ix      operator []
335     qu      operator ?
336     cv      operator <T> (conversion operator)
337     li<id>  operator "" <id>
338
339   FIXME: How about attributes?  */
340
341GCC_METHOD7 (gcc_decl, build_decl,
342	     const char *,	      /* Argument NAME.  */
343	     enum gcc_cp_symbol_kind, /* Argument SYM_KIND.  */
344	     gcc_type,		      /* Argument SYM_TYPE.  */
345	     const char *,	      /* Argument SUBSTITUTION_NAME.  */
346	     gcc_address,	      /* Argument ADDRESS.  */
347	     const char *,	      /* Argument FILENAME.  */
348	     unsigned int)	      /* Argument LINE_NUMBER.  */
349
350/* Supply the ADDRESS of one of the multiple clones of constructor or
351   destructor CDTOR.  The clone is specified by NAME, using the
352   following name mangling conventions:
353
354     C1      in-charge constructor
355     C2      not-in-charge constructor
356     C4      unified constructor
357     D0      deleting destructor
358     D1      in-charge destructor
359     D2      not-in-charge destructor
360     D4      unified destructor
361
362   The following information is not necessary to use the API.
363
364   C1 initializes an instance of the class (rather than of derived
365   classes), including virtual base classes, whereas C2 initializes a
366   sub-object (of the given class type) of an instance of some derived
367   class (or a full object that doesn't have any virtual base
368   classes).
369
370   D0 and D1 destruct an instance of the class, including virtual base
371   classes, but only the former calls operator delete to release the
372   object's storage at the end; D2 destructs a sub-object (of the
373   given class type) of an instance of a derived class (or a full
374   object that doesn't have any virtual base classes).
375
376   The [CD]4 manglings (and symbol definitions) are non-standard, but
377   GCC uses them in some cases: rather than assuming they are
378   in-charge or not-in-charge, they test the implicit argument that
379   the others ignore to tell how to behave.  These are used instead of
380   cloning when we just can't use aliases.  */
381
382GCC_METHOD3 (gcc_decl, define_cdtor_clone,
383	     const char *,	      /* Argument NAME.  */
384	     gcc_decl,		      /* Argument CDTOR.  */
385	     gcc_address)	      /* Argument ADDRESS.  */
386
387/* Return the type associated with the given declaration.  This is
388   most useful to obtain the type associated with a forward-declared
389   class, because it is the gcc_type, rather than the gcc_decl, that
390   has to be used to build other types, but build_decl returns a
391   gcc_decl rather than a gcc_type.  This call can in theory be used
392   to obtain the type from any other declaration; it is supposed to
393   return the same type that was supplied when the declaration was
394   created.  */
395
396GCC_METHOD1 (gcc_type, get_decl_type,
397	     gcc_decl)            /* Argument DECL.  */
398
399/* Return the declaration for a type.  */
400
401GCC_METHOD1 (gcc_decl, get_type_decl,
402	     gcc_type)            /* Argument TYPE.  */
403
404/* Declare DECL as a friend of the current class scope, if TYPE is
405   NULL, or of TYPE itself otherwise.  DECL may be a function or a
406   class, be they template generics, template specializations or not
407   templates.  TYPE must be a class type (not a template generic).
408
409   The add_friend call cannot introduce a declaration; even if the
410   friend is first declared as a friend in the source code, the
411   declaration belongs in the enclosing namespace, so it must be
412   introduced in that namespace, and the resulting declaration can
413   then be made a friend.
414
415   DECL cannot, however, be a member of a template class generic,
416   because we have no means to introduce their declarations.  This
417   interface has no notion of definitions for template generics.  As a
418   consequence, users of this interface must introduce each friend
419   template member specialization separately, i.e., instead of:
420
421     template <typename T> friend struct X<T>::M;
422
423   they must be declared as if they were:
424
425     friend struct X<onetype>::M;
426     friend struct X<anothertype>::M;
427     ... for each specialization of X.
428
429
430   Specializations of a template can have each others' members as
431   friends:
432
433     template <typename T> class foo {
434       int f();
435       template <typename U> friend int foo<U>::f();
436     };
437
438   It wouldn't always be possible to define all specializations of a
439   template class before introducing the friend declarations in their
440   expanded, per-specialization form.
441
442   In order to simplify such friend declarations, and to enable
443   incremental friend declarations as template specializations are
444   introduced, add_friend can be called after the befriending class is
445   fully defined, passing it a non-NULL TYPE argument naming the
446   befriending class type.  */
447
448GCC_METHOD2 (int /* bool */, add_friend,
449	     gcc_decl,		      /* Argument DECL.  */
450	     gcc_type)		      /* Argument TYPE.  */
451
452/* Return the type of a pointer to a given base type.  */
453
454GCC_METHOD1 (gcc_type, build_pointer_type,
455	     gcc_type)			/* Argument BASE_TYPE.  */
456
457/* Return the type of a reference to a given base type.  */
458
459GCC_METHOD2 (gcc_type, build_reference_type,
460	     gcc_type,			/* Argument BASE_TYPE.  */
461	     enum gcc_cp_ref_qualifiers)   /* Argument RQUALS.  */
462
463/* Create a new pointer-to-member type.  MEMBER_TYPE is the data
464   member type, while CLASS_TYPE is the class type containing the data
465   member.  For pointers to member functions, MEMBER_TYPE must be a
466   method type, and CLASS_TYPE must be specified even though it might
467   be possible to extract it from the method type.  */
468
469GCC_METHOD2 (gcc_type, build_pointer_to_member_type,
470	     gcc_type,			   /* Argument CLASS_TYPE.  */
471	     gcc_type) 			   /* Argument MEMBER_TYPE.  */
472
473/* Start a template parameter list scope and enters it, so that
474   subsequent build_type_template_parameter and
475   build_value_template_parameter calls create template parameters in
476   the list.  The list is closed by a build_decl call with
477   GCC_CP_SYMBOL_FUNCTION or GCC_CP_SYMBOL_CLASS, that, when the scope
478   is a template parameter list, declares a template function or a
479   template class with the then-closed parameter list.  The scope in
480   which the new declaration is to be introduced by build_decl must be
481   entered before calling start_template_decl, and build_decl returns
482   to that scope, from the template parameter list scope, before
483   introducing the declaration.  */
484
485GCC_METHOD0 (int /* bool */, start_template_decl)
486
487/* Build a typename template-parameter (e.g., the T in template
488   <typename T = X>).  Either PACK_P should be nonzero, to indicate an
489   argument pack (the last argument in a variadic template argument
490   list, as in template <typename... T>), or DEFAULT_TYPE may be
491   non-NULL to set the default type argument (e.g. X) for the template
492   parameter.  FILENAME and LINE_NUMBER may specify the source
493   location in which the template parameter was declared.  */
494
495GCC_METHOD5 (gcc_type, build_type_template_parameter,
496	     const char *,			      /* Argument ID.  */
497	     int /* bool */,			  /* Argument PACK_P.  */
498	     gcc_type,			    /* Argument DEFAULT_TYPE.  */
499	     const char *,			/* Argument FILENAME.  */
500	     unsigned int)		     /* Argument LINE_NUMBER.  */
501
502/* Build a template template-parameter (e.g., the T in template
503   <template <[...]> class T = X>).  DEFAULT_TEMPL may be non-NULL to
504   set the default type-template argument (e.g. X) for the template
505   template parameter.  FILENAME and LINE_NUMBER may specify the
506   source location in which the template parameter was declared.  */
507
508GCC_METHOD5 (gcc_utempl, build_template_template_parameter,
509	     const char *,			      /* Argument ID.  */
510	     int /* bool */,			  /* Argument PACK_P.  */
511	     gcc_utempl,		   /* Argument DEFAULT_TEMPL.  */
512	     const char *,			/* Argument FILENAME.  */
513	     unsigned int)		     /* Argument LINE_NUMBER.  */
514
515/* Build a value template-parameter (e.g., the V in template <typename
516   T, T V> or in template <int V = X>).  DEFAULT_VALUE may be non-NULL
517   to set the default value argument for the template parameter (e.g.,
518   X).  FILENAME and LINE_NUMBER may specify the source location in
519   which the template parameter was declared.  */
520
521GCC_METHOD5 (gcc_decl, build_value_template_parameter,
522	     gcc_type,			  	    /* Argument TYPE.  */
523	     const char *,			      /* Argument ID.  */
524	     gcc_expr,			   /* Argument DEFAULT_VALUE.  */
525	     const char *,			/* Argument FILENAME.  */
526	     unsigned int)		     /* Argument LINE_NUMBER.  */
527
528/* Build a template-dependent typename (e.g., typename T::bar or
529   typename T::template bart<X>).  ENCLOSING_TYPE should be the
530   template-dependent nested name specifier (e.g., T), ID should be
531   the name of the member of the ENCLOSING_TYPE (e.g., bar or bart),
532   and TARGS should be non-NULL and specify the template arguments
533   (e.g. <X>) iff ID is to name a class template.
534
535   In this and other calls, a template-dependent nested name specifier
536   may be a template class parameter (build_type_template_parameter),
537   a specialization (returned by build_dependent_type_template_id) of
538   a template template parameter (returned by
539   build_template_template_parameter) or a member type thereof
540   (returned by build_dependent_typename itself).  */
541
542GCC_METHOD3 (gcc_type, build_dependent_typename,
543	     gcc_type,			  /* Argument ENCLOSING_TYPE.  */
544	     const char *,			      /* Argument ID.  */
545	     const struct gcc_cp_template_args *)  /* Argument TARGS.  */
546
547/* Build a template-dependent class template (e.g., T::template bart).
548   ENCLOSING_TYPE should be the template-dependent nested name
549   specifier (e.g., T), ID should be the name of the class template
550   member of the ENCLOSING_TYPE (e.g., bart).  */
551
552GCC_METHOD2 (gcc_utempl, build_dependent_class_template,
553	     gcc_type,			  /* Argument ENCLOSING_TYPE.  */
554	     const char *)			      /* Argument ID.  */
555
556/* Build a template-dependent type template-id (e.g., T<A>).
557   TEMPLATE_DECL should be a template template parameter (e.g., the T
558   in template <template <[...]> class T = X>), and TARGS should
559   specify the template arguments (e.g. <A>).  */
560
561GCC_METHOD2 (gcc_type, build_dependent_type_template_id,
562	     gcc_utempl,		   /* Argument TEMPLATE_DECL.  */
563	     const struct gcc_cp_template_args *)  /* Argument TARGS.  */
564
565/* Build a template-dependent expression (e.g., S::val or S::template
566   mtf<X>, or unqualified f or template tf<X>).
567
568   ENCLOSING_SCOPE should be a template-dependent nested name
569   specifier (e.g., T), a resolved namespace or class decl, or NULL
570   for unqualified names; ID should be the name of the member of the
571   ENCLOSING_SCOPE (e.g., val or mtf) or unqualified overloaded
572   function; and TARGS should list template arguments (e.g. <X>) when
573   mtf or tf are to name a template function, or be NULL otherwise.
574
575   Unqualified names and namespace- or class-qualified names can only
576   resolve to overloaded functions, to be used in contexts that
577   involve overload resolution that cannot be resolved because of
578   template-dependent argument or return types, such as call
579   expressions with template-dependent arguments, conversion
580   expressions to function types with template-dependent argument
581   types or the like.  Other cases of unqualified or
582   non-template-dependent-qualified names should NOT use this
583   function, and use decl_expr to convert the appropriate function or
584   object declaration to an expression.
585
586   If ID is the name of a special member function, FLAGS should be
587   GCC_CP_SYMBOL_FUNCTION|GCC_CP_FLAG_SPECIAL_FUNCTION, and ID should
588   be one of the encodings for special member functions documented in
589   build_decl.  Otherwise, FLAGS should be GCC_CP_SYMBOL_MASK, which
590   suggests the symbol kind is not known (though we know it is not a
591   type).
592
593   If ID denotes a conversion operator, CONV_TYPE should name the
594   target type of the conversion.  Otherwise, CONV_TYPE must be
595   NULL.  */
596
597GCC_METHOD5 (gcc_expr, build_dependent_expr,
598	     gcc_decl,			 /* Argument ENCLOSING_SCOPE.  */
599	     enum gcc_cp_symbol_kind,		   /* Argument FLAGS.  */
600	     const char *,			    /* Argument NAME.  */
601	     gcc_type,			       /* Argument CONV_TYPE.  */
602	     const struct gcc_cp_template_args *)  /* Argument TARGS.  */
603
604/* Build a gcc_expr for the value VALUE in type TYPE.  */
605
606GCC_METHOD2 (gcc_expr, build_literal_expr,
607	     gcc_type,		  /* Argument TYPE.  */
608	     unsigned long)	  /* Argument VALUE.  */
609
610/* Build a gcc_expr that denotes DECL, the declaration of a variable
611   or function in namespace scope, or of a static member variable or
612   function.  Use QUALIFIED_P to build the operand of unary & so as to
613   compute a pointer-to-member, rather than a regular pointer.  */
614
615GCC_METHOD2 (gcc_expr, build_decl_expr,
616	     gcc_decl,			/* Argument DECL.  */
617	     int /* bool */)		/* Argument QUALIFIED_P.  */
618
619/* Build a gcc_expr that denotes the unary operation UNARY_OP applied
620   to the gcc_expr OPERAND.  For non-expr operands, see
621   unary_type_expr.  Besides the UNARY_OP encodings used for operator
622   names, we support "pp_" for preincrement, and "mm_" for
623   predecrement, "nx" for noexcept, "tw" for throw, "tr" for rethrow
624   (pass NULL as the operand), "te" for typeid, "sz" for sizeof, "az"
625   for alignof, "dl" for delete, "gsdl" for ::delete, "da" for
626   delete[], "gsda" for ::delete[], "sp" for pack expansion, "sZ" for
627   sizeof...(function argument pack).  */
628
629GCC_METHOD2 (gcc_expr, build_unary_expr,
630	     const char *,	  /* Argument UNARY_OP.  */
631	     gcc_expr)		  /* Argument OPERAND.  */
632
633/* Build a gcc_expr that denotes the binary operation BINARY_OP
634   applied to gcc_exprs OPERAND1 and OPERAND2.  Besides the BINARY_OP
635   encodings used for operator names, we support "ds" for the operator
636   token ".*" and "dt" for the operator token ".".  When using
637   operators that take a name as their second operand ("." and "->")
638   use decl_expr to convert the gcc_decl of the member name to a
639   gcc_expr, if the member name wasn't created with
640   e.g. build_dependent_expr.  */
641
642GCC_METHOD3 (gcc_expr, build_binary_expr,
643	     const char *,	  /* Argument BINARY_OP.  */
644	     gcc_expr,		  /* Argument OPERAND1.  */
645	     gcc_expr)		  /* Argument OPERAND2.  */
646
647/* Build a gcc_expr that denotes the ternary operation TERNARY_OP
648   applied to gcc_exprs OPERAND1, OPERAND2 and OPERAND3.  The only
649   supported TERNARY_OP is "qu", for the "?:" operator.  */
650
651GCC_METHOD4 (gcc_expr, build_ternary_expr,
652	     const char *,	  /* Argument TERNARY_OP.  */
653	     gcc_expr,		  /* Argument OPERAND1.  */
654	     gcc_expr,		  /* Argument OPERAND2.  */
655	     gcc_expr)		  /* Argument OPERAND3.  */
656
657/* Build a gcc_expr that denotes the unary operation UNARY_OP applied
658   to the gcc_type OPERAND.  Supported unary operations taking types
659   are "ti" for typeid, "st" for sizeof, "at" for alignof, and "sZ"
660   for sizeof...(template argument pack).  */
661
662GCC_METHOD2 (gcc_expr, build_unary_type_expr,
663	     const char *,	  /* Argument UNARY_OP.  */
664	     gcc_type)		  /* Argument OPERAND.  */
665
666/* Build a gcc_expr that denotes the binary operation BINARY_OP
667   applied to gcc_type OPERAND1 and gcc_expr OPERAND2.  Use this for
668   all kinds of (single-argument) type casts ("dc", "sc", "cc", "rc"
669   for dynamic, static, const and reinterpret casts, respectively;
670   "cv" for functional or C-style casts).  */
671
672GCC_METHOD3 (gcc_expr, build_cast_expr,
673	     const char *,	  /* Argument BINARY_OP.  */
674	     gcc_type,		  /* Argument OPERAND1.  */
675	     gcc_expr)		  /* Argument OPERAND2.  */
676
677/* Build a gcc_expr that denotes the conversion of an expression list
678   VALUES to TYPE, with ("tl") or without ("cv") braces, or a braced
679   initializer list of unspecified type (e.g., a component of another
680   braced initializer list; pass "il" for CONV_OP, and NULL for
681   TYPE).  */
682
683GCC_METHOD3 (gcc_expr, build_expression_list_expr,
684	     const char *,			 /* Argument CONV_OP.  */
685	     gcc_type,				    /* Argument TYPE.  */
686	     const struct gcc_cp_function_args *) /* Argument VALUES.  */
687
688/* Build a gcc_expr that denotes a new ("nw") or new[] ("na")
689   expression of TYPE, with or without a GLOBAL_NS qualifier (prefix
690   the NEW_OP with "gs"), with or without PLACEMENT, with or without
691   INITIALIZER.  If it's not a placement new, PLACEMENT must be NULL
692   (rather than a zero-length placement arg list).  If there's no
693   specified initializer, INITIALIZER must be NULL; a zero-length arg
694   list stands for a default initializer.  */
695
696GCC_METHOD4 (gcc_expr, build_new_expr,
697	     const char *,			       /* Argument NEW_OP.  */
698	     const struct gcc_cp_function_args *,   /* Argument PLACEMENT.  */
699	     gcc_type,					 /* Argument TYPE.  */
700	     const struct gcc_cp_function_args *) /* Argument INITIALIZER.  */
701
702/* Return a call expression that calls CALLABLE with arguments ARGS.
703   CALLABLE may be a function, a callable object, a pointer to
704   function, an unresolved expression, an unresolved overload set, an
705   object expression combined with a member function overload set or a
706   pointer-to-member.  If QUALIFIED_P, CALLABLE will be interpreted as
707   a qualified name, preventing virtual function dispatch.  */
708
709GCC_METHOD3 (gcc_expr, build_call_expr,
710	     gcc_expr,			      /* Argument CALLABLE.  */
711	     int /* bool */,		   /* Argument QUALIFIED_P.  */
712	     const struct gcc_cp_function_args *) /* Argument ARGS.  */
713
714/* Return the type of the gcc_expr OPERAND.
715   Use this for decltype.
716   For decltype (auto), pass a NULL OPERAND.
717
718   Note: for template-dependent expressions, the result is NULL,
719   because the type is only computed when template argument
720   substitution is performed.  */
721
722GCC_METHOD1 (gcc_type, get_expr_type,
723	     gcc_expr)		  /* Argument OPERAND.  */
724
725/* Introduce a specialization of a template function.
726
727   TEMPLATE_DECL is the template function, and TARGS are the arguments
728   for the specialization.  ADDRESS is the address of the
729   specialization.  FILENAME and LINE_NUMBER specify the source
730   location associated with the template function specialization.  */
731
732GCC_METHOD5 (gcc_decl, build_function_template_specialization,
733	     gcc_decl,			   /* Argument TEMPLATE_DECL.  */
734	     const struct gcc_cp_template_args *,  /* Argument TARGS.  */
735	     gcc_address,			 /* Argument ADDRESS.  */
736	     const char *,	      /* Argument FILENAME.  */
737	     unsigned int)	      /* Argument LINE_NUMBER.  */
738
739/* Specialize a template class as an incomplete type.  A definition
740   can be supplied later, with start_class_type.
741
742   TEMPLATE_DECL is the template class, and TARGS are the arguments
743   for the specialization.  FILENAME and LINE_NUMBER specify the
744   source location associated with the template class
745   specialization.  */
746
747GCC_METHOD4 (gcc_decl, build_class_template_specialization,
748	     gcc_decl,			   /* Argument TEMPLATE_DECL.  */
749	     const struct gcc_cp_template_args *,  /* Argument TARGS.  */
750	     const char *,	      /* Argument FILENAME.  */
751	     unsigned int)	      /* Argument LINE_NUMBER.  */
752
753/* Start defining a 'class', 'struct' or 'union' type, entering its
754   own binding level.  Initially it has no fields.
755
756   TYPEDECL is the forward-declaration of the type, returned by
757   build_decl.  BASE_CLASSES indicate the base classes of class NAME.
758   FILENAME and LINE_NUMBER specify the source location associated
759   with the class definition, should they be different from those of
760   the forward declaration.  */
761
762GCC_METHOD4 (gcc_type, start_class_type,
763	     gcc_decl,		      /* Argument TYPEDECL.  */
764	     const struct gcc_vbase_array *,/* Argument BASE_CLASSES.  */
765	     const char *,	      /* Argument FILENAME.  */
766	     unsigned int)	      /* Argument LINE_NUMBER.  */
767
768/* Create a new closure class type, record it as the
769   DISCRIMINATOR-numbered closure type in the current scope (or
770   associated with EXTRA_SCOPE, if non-NULL), and enter the closure
771   type's own binding level.  This primitive would sort of combine
772   build_decl and start_class_type, if they could be used to introduce
773   a closure type.  Initially it has no fields.
774
775   FILENAME and LINE_NUMBER specify the source location associated
776   with the class.  EXTRA_SCOPE, if non-NULL, must be a PARM_DECL of
777   the current function, or a FIELD_DECL of the current class.  If it
778   is NULL, the current scope must be a function.  */
779
780GCC_METHOD5 (gcc_type, start_closure_class_type,
781	     int,		      /* Argument DISCRIMINATOR.  */
782	     gcc_decl,		      /* Argument EXTRA_SCOPE.  */
783	     enum gcc_cp_symbol_kind, /* Argument FLAGS.  */
784	     const char *,	      /* Argument FILENAME.  */
785	     unsigned int)	      /* Argument LINE_NUMBER.  */
786
787/* Add a non-static data member to the most-recently-started
788   unfinished struct or union type.  FIELD_NAME is the field's name.
789   FIELD_TYPE is the type of the field.  BITSIZE and BITPOS indicate
790   where in the struct the field occurs.  */
791
792GCC_METHOD5 (gcc_decl, build_field,
793	     const char *,		   /* Argument FIELD_NAME.  */
794	     gcc_type,			   /* Argument FIELD_TYPE.  */
795	     enum gcc_cp_symbol_kind,	   /* Argument FIELD_FLAGS.  */
796	     unsigned long,		   /* Argument BITSIZE.  */
797	     unsigned long)		   /* Argument BITPOS.  */
798
799/* After all the fields have been added to a struct, class or union,
800   the struct or union type must be "finished".  This does some final
801   cleanups in GCC, and pops to the binding level that was in effect
802   before the matching start_class_type or
803   start_closure_class_type.  */
804
805GCC_METHOD1 (int /* bool */, finish_class_type,
806	     unsigned long)		   /* Argument SIZE_IN_BYTES.  */
807
808/* Create a new 'enum' type, and record it in the current binding
809   level.  The new type initially has no associated constants.
810
811   NAME is the enum name.  FILENAME and LINE_NUMBER specify its source
812   location.  */
813
814GCC_METHOD5 (gcc_type, start_enum_type,
815	     const char *,	      /* Argument NAME.  */
816	     gcc_type,		      /* Argument UNDERLYING_INT_TYPE. */
817	     enum gcc_cp_symbol_kind, /* Argument FLAGS.  */
818	     const char *,	      /* Argument FILENAME.  */
819	     unsigned int)	      /* Argument LINE_NUMBER.  */
820
821/* Add a new constant to an enum type.  NAME is the constant's name
822   and VALUE is its value.  Returns a gcc_decl for the constant.  */
823
824GCC_METHOD3 (gcc_decl, build_enum_constant,
825	     gcc_type,		       /* Argument ENUM_TYPE.  */
826	     const char *,	       /* Argument NAME.  */
827	     unsigned long)	       /* Argument VALUE.  */
828
829/* After all the constants have been added to an enum, the type must
830   be "finished".  This does some final cleanups in GCC.  */
831
832GCC_METHOD1 (int /* bool */, finish_enum_type,
833	     gcc_type)		       /* Argument ENUM_TYPE.  */
834
835/* Create a new function type.  RETURN_TYPE is the type returned by
836   the function, and ARGUMENT_TYPES is a vector, of length NARGS, of
837   the argument types.  IS_VARARGS is true if the function is
838   varargs.  */
839
840GCC_METHOD3 (gcc_type, build_function_type,
841	     gcc_type,			   /* Argument RETURN_TYPE.  */
842	     const struct gcc_type_array *,/* Argument ARGUMENT_TYPES.  */
843	     int /* bool */)		   /* Argument IS_VARARGS.  */
844
845/* Create a variant of a function type with an exception
846   specification.  FUNCTION_TYPE is a function or method type.
847   EXCEPT_TYPES is an array with the list of exception types.  Zero as
848   the array length implies throw() AKA noexcept(true); NULL as the
849   pointer to gcc_type_array implies noexcept(false), which is almost
850   equivalent (but distinguishable by the compiler) to an unspecified
851   exception list.  */
852
853GCC_METHOD2 (gcc_type, build_exception_spec_variant,
854	     gcc_type,			   /* Argument FUNCTION_TYPE.  */
855	     const struct gcc_type_array *)/* Argument EXCEPT_TYPES.  */
856
857/* Create a new non-static member function type.  FUNC_TYPE is the
858   method prototype, without the implicit THIS pointer, added as a
859   pointer to the QUALS-qualified CLASS_TYPE.  If CLASS_TYPE is NULL,
860   this creates a cv-qualified (member) function type not associated
861   with any specific class, as needed to support "typedef void f(int)
862   const;", which can later be used to declare member functions and
863   pointers to member functions.  */
864
865GCC_METHOD4 (gcc_type, build_method_type,
866	     gcc_type,			   /* Argument CLASS_TYPE.  */
867	     gcc_type, 			   /* Argument FUNC_TYPE.  */
868	     enum gcc_cp_qualifiers,	   /* Argument QUALS.  */
869	     enum gcc_cp_ref_qualifiers)   /* Argument RQUALS.  */
870
871/* Return a declaration for the (INDEX - 1)th argument of
872   FUNCTION_DECL, i.e., for the first argument, use zero as the index.
873   If FUNCTION_DECL is a non-static member function, use -1 to get the
874   implicit THIS parameter.  */
875
876GCC_METHOD2 (gcc_decl, get_function_parameter_decl,
877	     gcc_decl,			     /* Argument FUNCTION_DECL.  */
878	     int)				     /* Argument INDEX.  */
879
880/* Return a lambda expr that constructs an instance of CLOSURE_TYPE.
881   Only lambda exprs without any captures can be correctly created
882   through these mechanisms; that's all we need to support lambdas
883   expressions in default parameters, the only kind that may have to
884   be introduced through this interface.  */
885
886GCC_METHOD1 (gcc_expr, build_lambda_expr,
887	     gcc_type)			      /* Argument CLOSURE_TYPE.  */
888
889/* Return an integer type with the given properties.  If BUILTIN_NAME
890   is non-NULL, it must name a builtin integral type with the given
891   signedness and size, and that is the type that will be returned.  */
892
893GCC_METHOD3 (gcc_type, get_int_type,
894	     int /* bool */,		   /* Argument IS_UNSIGNED.  */
895	     unsigned long,                /* Argument SIZE_IN_BYTES.  */
896	     const char *)		   /* Argument BUILTIN_NAME.  */
897
898/* Return the 'char' type, a distinct type from both 'signed char' and
899   'unsigned char' returned by int_type.  */
900
901GCC_METHOD0 (gcc_type, get_char_type)
902
903/* Return a floating point type with the given properties.  If BUILTIN_NAME
904   is non-NULL, it must name a builtin integral type with the given
905   signedness and size, and that is the type that will be returned.  */
906
907GCC_METHOD2 (gcc_type, get_float_type,
908	     unsigned long,                /* Argument SIZE_IN_BYTES.  */
909	     const char *)		   /* Argument BUILTIN_NAME.  */
910
911/* Return the 'void' type.  */
912
913GCC_METHOD0 (gcc_type, get_void_type)
914
915/* Return the 'bool' type.  */
916
917GCC_METHOD0 (gcc_type, get_bool_type)
918
919/* Return the std::nullptr_t type.  */
920
921GCC_METHOD0 (gcc_type, get_nullptr_type)
922
923/* Return the nullptr constant.  */
924
925GCC_METHOD0 (gcc_expr, get_nullptr_constant)
926
927/* Create a new array type.  If NUM_ELEMENTS is -1, then the array
928   is assumed to have an unknown length.  */
929
930GCC_METHOD2 (gcc_type, build_array_type,
931	     gcc_type,			  /* Argument ELEMENT_TYPE.  */
932	     int)			  /* Argument NUM_ELEMENTS.  */
933
934/* Create a new array type.  NUM_ELEMENTS is a template-dependent
935   expression.  */
936
937GCC_METHOD2 (gcc_type, build_dependent_array_type,
938	     gcc_type,			  /* Argument ELEMENT_TYPE.  */
939	     gcc_expr)			  /* Argument NUM_ELEMENTS.  */
940
941/* Create a new variably-sized array type.  UPPER_BOUND_NAME is the
942   name of a local variable that holds the upper bound of the array;
943   it is one less than the array size.  */
944
945GCC_METHOD2 (gcc_type, build_vla_array_type,
946	     gcc_type,			  /* Argument ELEMENT_TYPE.  */
947	     const char *)		  /* Argument UPPER_BOUND_NAME.  */
948
949/* Return a qualified variant of a given base type.  QUALIFIERS says
950   which qualifiers to use; it is composed of or'd together
951   constants from 'enum gcc_cp_qualifiers'.  */
952
953GCC_METHOD2 (gcc_type, build_qualified_type,
954	     gcc_type,			      /* Argument UNQUALIFIED_TYPE.  */
955	     enum gcc_cp_qualifiers)	      /* Argument QUALIFIERS.  */
956
957/* Build a complex type given its element type.  */
958
959GCC_METHOD1 (gcc_type, build_complex_type,
960	     gcc_type)			  /* Argument ELEMENT_TYPE.  */
961
962/* Build a vector type given its element type and number of
963   elements.  */
964
965GCC_METHOD2 (gcc_type, build_vector_type,
966	     gcc_type,			  /* Argument ELEMENT_TYPE.  */
967	     int)			  /* Argument NUM_ELEMENTS.  */
968
969/* Build a constant.  NAME is the constant's name and VALUE is its
970   value.  FILENAME and LINE_NUMBER refer to the type's source
971   location.  If this is not known, FILENAME can be NULL and
972   LINE_NUMBER can be 0.  */
973
974GCC_METHOD5 (int /* bool */, build_constant,
975	     gcc_type,		  /* Argument TYPE.  */
976	     const char *,	  /* Argument NAME.  */
977	     unsigned long,	  /* Argument VALUE.  */
978	     const char *,	  /* Argument FILENAME.  */
979	     unsigned int)	  /* Argument LINE_NUMBER.  */
980
981/* Emit an error and return an error type object.  */
982
983GCC_METHOD1 (gcc_type, error,
984	     const char *)		 /* Argument MESSAGE.  */
985
986/* Declare a static_assert with the given CONDITION and ERRORMSG at
987   FILENAME:LINE_NUMBER.  */
988
989GCC_METHOD4 (int /* bool */, add_static_assert,
990	     gcc_expr,     /* Argument CONDITION.  */
991	     const char *, /* Argument ERRORMSG.  */
992	     const char *, /* Argument FILENAME.  */
993	     unsigned int) /* Argument LINE_NUMBER.  */
994
995#if 0
996
997/* FIXME: We don't want to expose the internal implementation detail
998   that default parms are stored in function types, and it's not clear
999   how this or other approaches would interact with the type sharing
1000   of e.g. ctor clones, so we're leaving this out, since default args
1001   are not even present in debug information anyway.  Besides, the set
1002   of default args for a function may grow within its scope, and vary
1003   independently in other scopes.  */
1004
1005/* Create a modified version of a function type that has default
1006   values for some of its arguments.  The returned type should ONLY be
1007   used to define functions or methods, never to declare parameters,
1008   variables, types or the like.
1009
1010   DEFAULTS must have at most as many N_ELEMENTS as there are
1011   arguments without default values in FUNCTION_TYPE.  Say, if
1012   FUNCTION_TYPE has an argument list such as (T1, T2, T3, T4 = V0)
1013   and DEFAULTS has 2 elements (V1, V2), the returned type will have
1014   the following argument list: (T1, T2 = V1, T3 = V2, T4 = V0).
1015
1016   Any NULL expressions in DEFAULTS will be marked as deferred, and
1017   they should be filled in with set_deferred_function_default_args.  */
1018
1019GCC_METHOD2 (gcc_type, add_function_default_args,
1020	     gcc_type,			     /* Argument FUNCTION_TYPE.  */
1021	     const struct gcc_cp_function_args *) /* Argument DEFAULTS.  */
1022
1023/* Fill in the first deferred default args in FUNCTION_DECL with the
1024   expressions given in DEFAULTS.  This can be used when the
1025   declaration of a parameter is needed to create a default
1026   expression, such as taking the size of an earlier parameter, or
1027   building a lambda expression in the parameter's context.  */
1028
1029GCC_METHOD2 (int /* bool */, set_deferred_function_default_args,
1030	     gcc_decl,			     /* Argument FUNCTION_DECL.  */
1031	     const struct gcc_cp_function_args *) /* Argument DEFAULTS.  */
1032
1033#endif
1034
1035
1036/* When you add entry points, add them at the end, so that the new API
1037   version remains compatible with the old version.
1038
1039   The following conventions have been observed as to naming entry points:
1040
1041   - build_* creates (and maybe records) something and returns it;
1042   - add_* creates and records something, but doesn't return it;
1043   - get_* obtains something without creating it;
1044   - start_* marks the beginning of a compound (type, list, ...);
1045   - finish_* completes the compound when needed.
1046
1047  Entry points that return an int (bool) and don't have a return value
1048  specification return nonzero (true) on success and zero (false) on
1049  failure.  This is in line with libcc1's conventions of returning a
1050  zero-initialized value in case of e.g. a transport error.  */
1051