/* Interface between GCC C++ FE and GDB -*- c -*- Copyright (C) 2014-2020 Free Software Foundation, Inc. This file is part of GCC. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see . */ /* Push namespace NAME as the current binding level, to which newly-introduced decls will be bound. An empty string identifies the global namespace, whereas NULL identifies an anonymous namespace. A namespace named NAME is created in the current scope, if needed. If the newly-created namespace is to be an inline namespace, see make_namespace_inline. */ GCC_METHOD1 (int /* bool */, push_namespace, const char *) /* Argument NAME. */ /* Push TYPE as the current binding level, making its members visible for name lookup. The current scope before the call must be the scope in which the class was declared. This should be used if the definition of a class is already finished, but one wishes to define a nested class, or to enter the scope of one of its member functions. */ GCC_METHOD1 (int /* bool */, push_class, gcc_type) /* Argument TYPE. */ /* Push FUNCTION_DECL as the current (empty) binding level (see reactivate_decl). The current enclosing scope before the call must be the scope in which the function was declared. */ GCC_METHOD1 (int /* bool */, push_function, gcc_decl) /* Argument FUNCTION_DECL. */ /* Make DECL visible (again?) within SCOPE. When SCOPE is NULL, it means the current scope; if it is not NULL, it must name a function that is currently active, even if not at the top of the binding chain. This function can be used to make e.g. a global function or variable visible in a namespace or local scope (overriding another enclosing definition of the same name), but its most common expected use of this primitive, that gives it its name, is to make declarations visible again after reentering a function scope, because when a function is entered with push_function, that does NOT make any of the declarations nested in it visible for name lookup. There is a reason/excuse for that: unlike namespaces and classes, G++ doesn't ever have to reenter function scopes, so its name resolution infrastructure is not prepared to do that. But wait, there is also a good use for this apparent limitation: a function may contain multiple scopes (blocks), and the name may be bound to different symbols in each of these scopes. With this interface, as we reenter a function scope, we may choose which symbols to make visible for the code snippet, or, if there could be template functions in local scopes, for unresolved names in nested template class default arguments, or in nested template function signatures. As for making a local declaration visible for the code snippet, there are two possibilities: a) introduce it upfront, while entering the scope for the user expression (see the enter_scope callback, called by g++ when encountering the push_user_expression pragma), which might save some scope switching and reactivate_decl (though this can't be helped if some declarations have to be introduced and discarded, because of multiple definitions of the same name in different scopes within a function: they have to be defined in discriminator order); or b) introduce it when its name is looked up, entering the scope, introducing the declaration, leaving the scope, and then reactivating the declaration in its local scope. Here's some more detail on how reactivate_decl works. Say there's a function foo whose body looks like this: { { // point 1 class c {} o __attribute__ ((__used__)); // c , o } struct c { void f() { // point 2 } } o __attribute__ ((__used__)); // c_0, o_0 { class c {} p __attribute__ ((__used__)); // c_1, p // point 3 o.f(); } } When we are about to define class c at point 1, we enter the function foo scope, and since no symbols are visible at point 1, we proceed to declare class c. We may then define the class right away, or, if we leave the function scope, and we later wish to define it, or to define object o, we can reenter the scope and just use the previously-obtained gcc_decl to define the class, without having to reactivate the declaration. Now, if we are to set up the binding context for point 2, we have to define c_0::f, and in order to do so, we have to declare and define c_0. Before we can declare c_0, we MUST at least declare c. As a general rule, before we can declare or define any local name with a discriminator, we have to at least declare any other occurrences of the same name in the same enclosing entity with lower or absent discriminator. So, we declare c, then we leave the function scope and reenter it so as to declare c_0 (also with name "c", which is why we have to leave and reenter the function scope, otherwise we would get an error because of the duplicate definition; g++ will assign a discriminator because it still remembers there was an earlier declaration of c_0 within the function, it's just no longer in scope), then we can define c_0, including its member function f. Likewise, if we wish to define o_0, we have to define o first. If we wish to declare (and maybe then define) c_1, we have to at least declare (c and then) c_0 first. Then, as we set up the binding context to compile a code snippet at point 3, we may choose to activate c_1, o_0 and p upfront, declaring and discarding c, c_0 and o, and then reentering the funciton scope to declare c_1, o_0 and p; or we can wait for oracle lookups of c, o or p. If c is looked up, and the debugger resolves c in the scope to c_1, it is expected to enter the function scope from the top level, declare c, leave it, reenter it, declare c_0, leave it, reenter it, declare c_1, leave it, and then reactivate c_1 in the function scope. If c_1 is needed as a complete type, the definition may be given right after the declaration, or the scope will have to be reentered in order to define the class. . If the code snippet is at point 2, we don't need to (re)activate any declaration: nothing from any local scope is visible. Just entering the scope of the class containing member function f reactivates the names of its members, including the class name itself. */ GCC_METHOD2 (int /* bool */, reactivate_decl, gcc_decl, /* Argument DECL. */ gcc_decl) /* Argument SCOPE. */ /* Pop the namespace last entered with push_namespace, or class last entered with push_class, or function last entered with push_function, restoring the binding level in effect before the matching push_* call. */ GCC_METHOD0 (int /* bool */, pop_binding_level) /* Return the NAMESPACE_DECL, TYPE_DECL or FUNCTION_DECL of the binding level that would be popped by pop_scope. */ GCC_METHOD0 (gcc_decl, get_current_binding_level_decl) /* Make the current binding level an inline namespace. It must be a namespace to begin with. It is safe to call this more than once for the same namespace, but after the first call, subsequent ones will not return a success status. */ GCC_METHOD0 (int /* bool */, make_namespace_inline) /* Add USED_NS to the namespaces used by the current binding level. Use get_current_binding_level_decl to obtain USED_NS's gcc_decl. */ GCC_METHOD1 (int /* bool */, add_using_namespace, gcc_decl) /* Argument USED_NS. */ /* Introduce a namespace alias declaration, as in: namespace foo = [... ::] bar; After this call, namespace TARGET will be visible as ALIAS within the current namespace. Get the declaration for TARGET by calling get_current_binding_level_decl after pushing into it. */ GCC_METHOD2 (int /* bool */, add_namespace_alias, const char *, /* Argument ALIAS. */ gcc_decl) /* Argument TARGET. */ /* Introduce a using declaration, as in: using foo::bar; The TARGET decl names the qualifying scope (foo:: above) and the identifier (bar), but that does not mean that only TARGET will be brought into the current scope: all bindings of TARGET's identifier in the qualifying scope will be brought in. FLAGS should specify GCC_CP_SYMBOL_USING. If the current scope is a class scope, visibility flags must be supplied. Even when TARGET is template dependent, we don't need to specify whether or not it is a typename: the supplied declaration (that could be a template-dependent type converted to declaration by get_type_decl) indicates so. */ GCC_METHOD2 (int /* bool */, add_using_decl, enum gcc_cp_symbol_kind, /* Argument FLAGS. */ gcc_decl) /* Argument TARGET. */ /* Create a new "decl" in GCC, and bind it in the current binding level. A decl is a declaration, basically a kind of symbol. NAME is the name of the new symbol. SYM_KIND is the kind of symbol being requested. SYM_TYPE is the new symbol's C++ type; except for labels, where this is not meaningful and should be zero. If SUBSTITUTION_NAME is not NULL, then a reference to this decl in the source will later be substituted with a dereference of a variable of the given name. Otherwise, for symbols having an address (e.g., functions), ADDRESS is the address. FILENAME and LINE_NUMBER refer to the symbol's source location. If this is not known, FILENAME can be NULL and LINE_NUMBER can be 0. This function returns the new decl. Use this function to register typedefs, functions and variables to namespace and local binding levels, and typedefs, member functions (static or not), and static data members to class binding levels. Class members must have their access controls specified with GCC_CP_ACCESS_* flags in SYM_KIND. Note that, since access controls are disabled, we have no means to express private, protected and public. There are various flags that can be set in SYM_KIND to specify additional semantics. Look for GCC_CP_FLAGs in the definition of enum gcc_cp_symbol_kind in gcc-cp-interface.h. In order to define member functions, pass GCC_CP_SYMBOL_FUNCTION in SYM_KIND, and a function_type for static member functions or a method type for non-static member functions, including constructors and destructors. Use build_function_type to create a function type; for a method type, start by creating a function type without any compiler-introduced artificial arguments (the implicit this pointer, and the __in_chrg added to constructors and destructors, and __vtt_parm added to the former), and then use build_method_type to create the method type out of the class type and the function type. For operator functions, set GCC_CP_FLAG_SPECIAL_FUNCTION in SYM_KIND, in addition to any other applicable flags, and pass as NAME a string starting with the two-character mangling for operator name: "ps" for unary plus, "mL" for multiply and assign, *=; etc. Use "cv" for type converstion operators (the target type portion may be omitted, as it is taken from the return type in SYM_TYPE). For operator"", use "li" followed by the identifier (the mangled name mandates digits specifying the length of the identifier; if present, they determine the end of the identifier, otherwise, the identifier extents to the end of the string, so that "li3_Kme" and "li_Km" are equivalent). Constructors and destructors need special care, because for each constructor and destructor there may be multiple clones defined internally by the compiler. With build_decl, you can introduce the base declaration of a constructor or a destructor, setting GCC_CP_FLAG_SPECIAL_FUNCTION the flag and using names starting with capital "C" or "D", respectively, followed by a digit (see below), a blank, or NUL ('\0'). DO NOT supply an ADDRESS or a SUBSTITUTION_NAME to build_decl, it would be meaningless (and rejected) for the base declaration; use define_cdtor_clone to introduce the address of each clone. For constructor templates, declare the template with build_decl, and then, for each specialization, introduce it with build_function_template_specialization, and then define the addresses of each of its clones with define_cdtor_clone. NAMEs for GCC_CP_FLAG_SPECIAL_FUNCTION: NAME meaning C? constructor base declaration (? may be 1, 2, 4, blank or NUL) D? destructor base declaration (? may be 0, 1, 2, 4, blank or NUL) nw operator new na operator new[] dl operator delete da operator delete[] ps operator + (unary) ng operator - (unary) ad operator & (unary) de operator * (unary) co operator ~ pl operator + mi operator - ml operator * dv operator / rm operator % an operator & or operator | eo operator ^ aS operator = pL operator += mI operator -= mL operator *= dV operator /= rM operator %= aN operator &= oR operator |= eO operator ^= ls operator << rs operator >> lS operator <<= rS operator >>= eq operator == ne operator != lt operator < gt operator > le operator <= ge operator >= nt operator ! aa operator && oo operator || pp operator ++ mm operator -- cm operator , pm operator ->* pt operator -> cl operator () ix operator [] qu operator ? cv operator (conversion operator) li operator "" FIXME: How about attributes? */ GCC_METHOD7 (gcc_decl, build_decl, const char *, /* Argument NAME. */ enum gcc_cp_symbol_kind, /* Argument SYM_KIND. */ gcc_type, /* Argument SYM_TYPE. */ const char *, /* Argument SUBSTITUTION_NAME. */ gcc_address, /* Argument ADDRESS. */ const char *, /* Argument FILENAME. */ unsigned int) /* Argument LINE_NUMBER. */ /* Supply the ADDRESS of one of the multiple clones of constructor or destructor CDTOR. The clone is specified by NAME, using the following name mangling conventions: C1 in-charge constructor C2 not-in-charge constructor C4 unified constructor D0 deleting destructor D1 in-charge destructor D2 not-in-charge destructor D4 unified destructor The following information is not necessary to use the API. C1 initializes an instance of the class (rather than of derived classes), including virtual base classes, whereas C2 initializes a sub-object (of the given class type) of an instance of some derived class (or a full object that doesn't have any virtual base classes). D0 and D1 destruct an instance of the class, including virtual base classes, but only the former calls operator delete to release the object's storage at the end; D2 destructs a sub-object (of the given class type) of an instance of a derived class (or a full object that doesn't have any virtual base classes). The [CD]4 manglings (and symbol definitions) are non-standard, but GCC uses them in some cases: rather than assuming they are in-charge or not-in-charge, they test the implicit argument that the others ignore to tell how to behave. These are used instead of cloning when we just can't use aliases. */ GCC_METHOD3 (gcc_decl, define_cdtor_clone, const char *, /* Argument NAME. */ gcc_decl, /* Argument CDTOR. */ gcc_address) /* Argument ADDRESS. */ /* Return the type associated with the given declaration. This is most useful to obtain the type associated with a forward-declared class, because it is the gcc_type, rather than the gcc_decl, that has to be used to build other types, but build_decl returns a gcc_decl rather than a gcc_type. This call can in theory be used to obtain the type from any other declaration; it is supposed to return the same type that was supplied when the declaration was created. */ GCC_METHOD1 (gcc_type, get_decl_type, gcc_decl) /* Argument DECL. */ /* Return the declaration for a type. */ GCC_METHOD1 (gcc_decl, get_type_decl, gcc_type) /* Argument TYPE. */ /* Declare DECL as a friend of the current class scope, if TYPE is NULL, or of TYPE itself otherwise. DECL may be a function or a class, be they template generics, template specializations or not templates. TYPE must be a class type (not a template generic). The add_friend call cannot introduce a declaration; even if the friend is first declared as a friend in the source code, the declaration belongs in the enclosing namespace, so it must be introduced in that namespace, and the resulting declaration can then be made a friend. DECL cannot, however, be a member of a template class generic, because we have no means to introduce their declarations. This interface has no notion of definitions for template generics. As a consequence, users of this interface must introduce each friend template member specialization separately, i.e., instead of: template friend struct X::M; they must be declared as if they were: friend struct X::M; friend struct X::M; ... for each specialization of X. Specializations of a template can have each others' members as friends: template class foo { int f(); template friend int foo::f(); }; It wouldn't always be possible to define all specializations of a template class before introducing the friend declarations in their expanded, per-specialization form. In order to simplify such friend declarations, and to enable incremental friend declarations as template specializations are introduced, add_friend can be called after the befriending class is fully defined, passing it a non-NULL TYPE argument naming the befriending class type. */ GCC_METHOD2 (int /* bool */, add_friend, gcc_decl, /* Argument DECL. */ gcc_type) /* Argument TYPE. */ /* Return the type of a pointer to a given base type. */ GCC_METHOD1 (gcc_type, build_pointer_type, gcc_type) /* Argument BASE_TYPE. */ /* Return the type of a reference to a given base type. */ GCC_METHOD2 (gcc_type, build_reference_type, gcc_type, /* Argument BASE_TYPE. */ enum gcc_cp_ref_qualifiers) /* Argument RQUALS. */ /* Create a new pointer-to-member type. MEMBER_TYPE is the data member type, while CLASS_TYPE is the class type containing the data member. For pointers to member functions, MEMBER_TYPE must be a method type, and CLASS_TYPE must be specified even though it might be possible to extract it from the method type. */ GCC_METHOD2 (gcc_type, build_pointer_to_member_type, gcc_type, /* Argument CLASS_TYPE. */ gcc_type) /* Argument MEMBER_TYPE. */ /* Start a template parameter list scope and enters it, so that subsequent build_type_template_parameter and build_value_template_parameter calls create template parameters in the list. The list is closed by a build_decl call with GCC_CP_SYMBOL_FUNCTION or GCC_CP_SYMBOL_CLASS, that, when the scope is a template parameter list, declares a template function or a template class with the then-closed parameter list. The scope in which the new declaration is to be introduced by build_decl must be entered before calling start_template_decl, and build_decl returns to that scope, from the template parameter list scope, before introducing the declaration. */ GCC_METHOD0 (int /* bool */, start_template_decl) /* Build a typename template-parameter (e.g., the T in template ). Either PACK_P should be nonzero, to indicate an argument pack (the last argument in a variadic template argument list, as in template ), or DEFAULT_TYPE may be non-NULL to set the default type argument (e.g. X) for the template parameter. FILENAME and LINE_NUMBER may specify the source location in which the template parameter was declared. */ GCC_METHOD5 (gcc_type, build_type_template_parameter, const char *, /* Argument ID. */ int /* bool */, /* Argument PACK_P. */ gcc_type, /* Argument DEFAULT_TYPE. */ const char *, /* Argument FILENAME. */ unsigned int) /* Argument LINE_NUMBER. */ /* Build a template template-parameter (e.g., the T in template