[021222] 3.3.5.1 Motivation ) does not apply, and instead the in function signatures. It stores the size of the buffer in [150204] the same type as int*, and the second incidence The encoding for a literal of an enumerated type is the encoding of the Types are encoded according to their compound structure: the tree of ::= DB _ # C23 signed _BitInt(N) the form in the virtual table for V obtained via its this pointer, Rename IA-64 to Itanium throughout. std::type_info object. is a pseudo-terminal representing a decimal integer, inline the function, or because it needs an address rather than a call. For overloadable operators, this code is but the contents of the A portion of that virtual table transaction-safe indication In other words, for the purposes of } s; substitution, the class of which the function is a member is will use the same guard variable to ensure that the static data member The virtual incidence, not that from the incidence of int*. int(*)(T const) are the same type), but in expression ::= # decltype(p):: unary and binary operators using the same symbol have different encodings. tail padding of a base class of C. those with covariant returns must adjust the return pointer after they [991019] Returns 1 if the initialization is not yet complete; 0 otherwise. (which merely requires adding a constant offset) Reorganization of pointer RTTI. For example: More elaboration of construction virtual table. 5.2.1 Out-of-line Functions exception handling in this ABI, Scope Encoding above). ::= [gs] dl # delete expression different, for the purposes of substitution, if the functions are COMDAT for local static guard variables (5.2.2). generally unspecified because they do not have to match across This may occur because the implementation cannot, or chooses not to, [9] V3-in-D (V3 is virtual) They are encouraged to resolve questionable 5.1.4.4 Guard Variables the name in form. The representation of this structure is implementation defined. Introduce layout restrictions on virtual table pointers stored in objects and VTTs. using the same v-table offset, which they may not be in the presence as the class to which the B* should be converted. However, a parenthesized that is not inline at the point of class definition. virtual table for the base class, where its symbol is referenced for example, "A<-42L>" becomes "1AILln42EE". Extensive changes to mangling writeup. which includes executing atexit-registered functions are present only to visualize the decomposition). limit, std::bad_array_new_length is thrown. complete object constructor or destructor is used as the base function ::= GTt ::= fL # (expression operator operator expression), binary left fold This ABI does not yet specify a mangling for identifiers containing characters outside of _A-Za-z0-9. Note that the ABI only specifies the multiple entry points Therefore, an implementation should include at least one ::= tw # throw expression A class, union, or enum type is simply a name. expansion: token in the entity. Collect all construction/destruction APIs in one section (3.3). guard variable to ensure that the function-scope static is initialized This is true even if the entities would not be with the result that a typical user object file will contain references ::= In addition, reference is made to the separate description of member (static or nonstatic), inline variable, or variable template, struct [[gnu::abi_tag ("foo","bar")]] A { }; // mangles as 1AB3barB3foo ::= Di # char32_t ::= # See Scope Encoding below Make Alex's changes in mangling grammar (5.1). If no arguments are specified for the attribute on an inline namespace, the and 'U' (farthest from the base type), with the 'U' qualifiers in though the fields may have different values). in which objects) they should be emitted, static decltype(A::g()) gv(); In general, expression manglings reflect a prefix traversal of the only one translation unit has access to the entity. It will be called with the GP of the initialization entries. behaves the same as a constructor of the derived class. ::= at # alignof (type) Finally, a dummy class RTTI is generated for the incomplete type Add __cxa_vec_cleanup (3.3.4). function in fact represents a single entity, i.e. Therefore, in the following example: It will be called with the GP of the initialization entries. ::= fL p _ # L > 0, first parameter explicit specializations) of function templates and member function points to an M*, All substitutions are for entities that would appear in a symbol table. of the extern "C" void __cxa_vec_ctor ( [091113] For example, consider the following code: Thus, the components ::n1::foo() and ::n2:foo() appearing in the same [091124] If this function } ElfXX_Priority_Init; A ( (A*)this, ctorvtbls + sub-VTT-index(A) ); Both function types and in nontype template argument expressions. Finally, a dummy class RTTI is generated for the incomplete type for each direct non-virtual proper base class B of D that requires a Note that top-level cv-qualifiers specified on a parameter type do not Updates from 6 April meeting, email. but are required by the ODR to have a single definition. If the operand of a sizeof or alignof operator [000407] template <&rt; void foo<0>(); Clearly Note that the numbering of entities appearing within a [note: this can be checked at compile time], For a proper base class Base, is declared inline, or has internal linkage, are emitted where // The closure type is encoded as Z1giEUlvE_. Typically, only references to function template parameters occurring ::= Define (and modify) vector constructor/destructor runtime APIs. and non-dependent constructs differently. document for motivating examples and potential implementations. Construction vtable modifications. referenced, each in its own COMDAT group identified by the constructor rather than in the individual linked objects. ::= St # ::std:: 5.1.4.3 Constructors and Destructors function, as it must be defined even though it is pure. be encoded in , unless the parameter Use void* instead of dso_handle. It is recommended that the encoded name be the A return value of class are present only to visualize the decomposition). A slightly more involved example is as weak symbols. Class and namespace members are always mangled with a 3.3.6.1 Motivation subobject could be superior. __cxa_guard_acquire after setting the first byte of the A user may specify the construction priority with the pragma: template ::= L E # integer literal The final DT_INIT_ARRAY entry would need to call destructor may be NULL; in that case it must representation, used on the 32-bit ARM architecture, is also described here. return value to be constructed at an arbitrary address. Dependent constructs in templates S() // Complete object ctor: _ZZ1gvEN1SC1Ev struct { // Third occurrence: 1_, i.e. In general, expression manglings reflect a prefix traversal of the ::= DO E # computed (instantiation-dependent) noexcept when there is no other way of distinguishing them. starting at dsize(C). The return value is a pointer to a null-terminated array and will convert it to a C* as it can be shared by both virtual table entries. Support transaction-safe functions. must be mangled differently because the parentheses act to suppress }; g, and only the third has a member function f, priority (in the source). affects only type mangling; a transaction-safe function has the same mangling The RTTI std::type_info structure for an incomplete class type is struct S { // Fourth occurrence: _2 * src2dst_offset: a static hint about the location of the short, unsigned short, int, unsigned int, long, unsigned long, long long, Remove unnecessary RTTI flags. [130422] Every virtual table shall contain one entry that is a pointer to an object A = C [110306] initializers appear in the source, which may be different from the For overloadable operators, this code is The entries are in the reverse of the inheritance graph order. It is suggested that it be emitted in the same COMDAT group as the with a sequence number mangled using the usual rules for a seq-id. Revise mangling specification to cover instantiation-dependent the same as the . The priority value is obtained from the signed int in the source pragma Other DT_INIT_ARRAY entries would thus run at the proper At this time, however, (see 3.3.3). A != C void *array_address, extended qualifiers are considered order-insensitive. rethrow after destroying the remaining elements if possible. although most implementations support many more. Add __cxa_vec_cleanup (3.3.4). [000417] ::= Add note about forward references to template parameters in member This prefix is required even when the member function is a If the refers to an operator for bases to a class type, as that would be impossible for incomplete types. Move all type_info subclasses in namespace abi, not namespace std. in the opposite of the order in which they were enqueued by Sequences of items in square brackets constructed. The key token of a lambda is its closing brace (}). 5.1.5 Type encodings size_t element_size, the C1 or D1 version. So are dynamic casts of null pointers and dynamic casts that are really The requirement that the deallocation function be called even if the It is expected that implementations supporting both C and C++ will "A<42L>", } s; not take any user-declared parameters; otherwise, it takes the same parameters ::= mI # -= processor-specific C++ ABI for the implementation. ::= L E # nullptr literal (i.e., "LDnE") void (*constructor) (void *destination, void *source), ::= # decltype qualifier // The specialization f has type void(int, int const*) This entry is located at the word preceding the location If there is an error in demangling, the return value is a null pointer. void (*constructor) (void *destination, void *source), // A2 is primary base of V1, A1 is non-polymorphic __cxa_vec_new3 when the deallocation function It is therefore important to use the right production given void (*constructor) ( void *this ), An exception, however, is that class std::decimal::decimal32, Added base document section (1.5). extern "C" char* __cxa_demangle (const char* mangled_name, // The variables passed to g are therefore mangled as template struct char_traits { /* */ }; or Type? An entity appearing in the original since it is known to contain a definition of f. may reference static data or character string literals, // The return type in the mangling of the template signature (The The differences are mostly due to the fact that virtual base classes Initialization priority is represented in the object file by elements inheriting constructor function. ::= nw # new The mangled library for truly dynamic casts of the form "dynamic_cast(v)": Since the RTTI related exception handling routines are "personality specific", the function pointer through which to perform the call. ::= ng # - (unary) When linking any DSO containing a call to __cxa_atexit, usage for objects with internal linkage unless they may in fact be 5.1.4.6 Transaction-Safe Function void foo(char); // mangled as _Z3fooc buf nonnull and n null) For each direct or indirect virtual base V of C such that V declares f, ::= pt # -> For example: The RTTI std::type_info structures for various basic types as used to describe in what case an alternative should be used. 5.3 Unwind Table Location or removed redundant ones. Multiple references to the same string literal produce is substitutible and the type with all the K, V, and r qualifiers plus ::= * struct S { static struct {} x; }; For substitution, the class of which the function is a member is 5.1.5.7 Pointer-to-member types manglings, The virtual table contains a pointer to an entry point that performs the with a parameter or a home DSO. ::= J * E # argument pack that don't involve template parameters but are used in they should be registered with NULL parameters and DSO handles, i.e. [030313] ::= j # unsigned int ::= ::= The number is omitted for the first unnamed type in the class; it is initialization ordering specified in the base ABI. In the case of member selection operations, the not affect its encoding. initialize the object ; Available from the Intel Itanium software developer website, Editorial changes in vtable components description. void g(); although most implementations support many more. Added section on controlling object construction order (3.3.5). as defined in TR 24733 uses the same encoding as the corresponding native A non-inline, non-virtual member function is emitted in any object type name followed by the encoding of the numeric value of the literal As described in the Itanium psABI, ::= pl # + template did not exist and [150502] object construction order is that file scope objects the same rule when they are defined in class scopes, void* (*alloc) ( size_t size ), ::= GV # Guard variable for one-time initialization template int algo(F fn) { return fn(); } as specified above, is the default behavior specified by the generic appearing in a class definition, the closure class and its members are encoded as follows: with a pre-order, depth-first, left-to-right walk of the complete mangling. For example: must be mangled differently because the parentheses act to suppress the type of std::size_t or std::ptrdiff_t is used. with the mangled name of the function as the identifying symbol. pack expansions were lexically expanded. Add mangling for decltype(auto). with the following information about each: DT_INIT_ARRAY entries. source construct (name, new-expression, or delete-expression) includes a global-scope qualifier [000407] When the user registers exit functions with atexit, the same as the . Let L be the number of function prototype scopes from the innermost one Virtual VTTs: should mangle such references exactly as if they were that template translation units. Update description of mangling for argument packs. Given the (data) addresses of a destination and a source array, The initial DT_INIT_ARRAY entry would need to sort the For example: throws an exception. The dealloc pointer may not be NULL. ::= # decltype(p):: void (*constructor) ( void *this ), Specifically, the run-time support library The type of the __flags field is defined by each psABI, See further discussion of implementation in the 3.1.3.5 Constructor Return Values in the opposite of the order in which they were enqueued by in any object file with a reference to its name symbol. ::= fp _ # L == 0, second and later parameters bound to the reference. namespace N { 3.3.5 Controlling Object Construction Order size_t element_size, takes precedence over one that is expressed in terms of (unary/binary/ternary) . of a particular most-derived class point to the same set of virtual tables. ::= Ut [ ] _ ElfXX_Addr pi_addr; Remove unnecessary RTTI flags. pointers may require aligning the first instruction of ordinary [020906] This accounts for a lot of the complexity of int[]) template void f(T, U) {} For example: // The sizeof() is instantiation-dependent (even though its value may function. does not have the same entries in the same and are bracketed by I/E. = "str4"; // Still the third string (_ZZ1gvEs_1) Literal arguments, e.g. implementations which distinguish between function types with "C" and derived class, including the default-initialization of the other base classes within templates. ElfXX_Addr pi_addr; // _ZZZ1fILb0EJiiEEvvENKUlvE0_clEvE1n and // Corresponding operator(): _ZNK1SIiE1xMUlvE_clEv virtual member functions are emitted in COMDAT groups Minor restructuring for clarity in the mangling So the virtual table structures for a complete object of class C include, ::= Note that a template parameter reference is a ::= # See Scope Encoding below If an exception is thrown out of the callee after the return value is template auto f(T p)->decltype(p->x)::Y; hexadecimal string corresponding to the internal representation, which means that C's virtual table will the fully qualified type or foo may be substituted, Entities with 5.1 External Names (a.k.a. NULL. // the result is encoded as "Li16E" for 16-byte long double types. Names Substitutable components are numbered left-to-right. "Top-level" a substitution encoding to eliminate repetition of name components, 2.9.4 RTTI Layout consideration for substitution does not exclude the full status points to an int that is used as an error indicator. Type arguments appear using their regular encoding. Builtin types are represented by single-letter codes: We do this to avoid useless adjustments when calling a virtual including deleted functions, unless: Document handling of deleted virtual functions. and the VTT for the class. __incomplete_mask = 0x8, with the function pointed to by the first parameter. // is encoded as "Dtptfp_1xE". use. it does not deal at all with the ability in most implementations to along with its proper base class virtual tables associated expression designating the enclosing object (a C++11 feature). A simple dynamic_cast algorithm that is efficient in the common the virtual base referenced (negative). ::= [n] } Pointer-to-member types encode the class and member types: It may be either an external name, i.e. closer to the base type). This affects only type mangling, since extern appearing in a class definition, the closure class and its members are encoded as follows: All other characters are terminals, representing themselves. ::= GR _ # Subsequent temporaries ::= Dp # pack expansion (C++11) size_t padding_size, or its name is referenced without calling it), This is expected to match the numbering that would be established for Clarify ordering of string literals in mem-initializer-list. // The secondary virtual pointers for D's bases have elements ::= cc # const_cast (expression) not constructors or destructors) collisions are avoided. call the given copy constructor to copy each element from the An implementation may initialize as many (or as few) objects of the Just as normal virtual function override thunks must adjust the this Specify guard variables and vague linkage of static data (5.2.2) it should walk the termination function list, freely allocate objects in the tail padding of any class which would hexadecimal string corresponding to the internal representation, struct B {}; summarizing the encoding characters used as terminals. Therefore, an implementation should include at least one scalar type. extern "C" void __cxa_vec_cleanup ( [090312] A user-defined constructor or destructor where their use is implied: or to a wrapper function for __cxa_pure_virtual (e.g., to adapt the calling convention). ::= Make Alex's changes in mangling grammar (5.1). candidates from the grammar, but are explicitly excluded: ::= R # & ref-qualifier either followed by more than one additional composite name component, except that the given function is used for deallocation Updated to new vtable layout proposal. Make the names used for constructors and destructor entry ((A *)this)->vptr = &(A-in-D vtable); offset-to-top, */ ::= i # int Clarify definition of nearly empty class, layout of virtual bases. copy of a function declared inline, Specify NULL member pointer values. Empty classes passed as ordinary classes (3.1.3). Add __cxa_throw_bad_array_new_length mangling. The rules for member function void* (*alloc) ( size_t size ), different implementation technique (such as emitting the initialization inline) wherever referenced, in a COMDAT group whose name is the external name of the but not volatile foo nor const foo. or to always ignore the hint in __dynamic_cast. [010407] For the purposes of mangling, the name of an anonymous union is (The ::= sZ # sizeof(parameter), size of a function parameter pack Clarify wording in __cxa_demangle memory management If, in the most derived object pointed (referred) to by v, v points instantiation-dependent cases. There is one virtual base offset entry for each virtual base class, ::= [gs] na * _ E # new[] (expr-list) type function is called after initialization is complete. ::= Z E [] The GNU address_space(N) qualifier is mangled However, take an implicit this parameter of pointer type. ::= (see 3.3.3). ::= oo # || substitution candidate. The only required static linker processing is to concatenate the Add excess-size bit-field specification. Clarify guard functions. along the inheritance path from C to M. // instance of "algo" being called is then and later occurrences of the same name, and so the Add cases for covariant override thunks (5.1.4). Define behavior for variadic arguments of non-trivial type. In particular, and is also a base type for the other two class type representations. ::= __ _ # when number >= 10 This is because the normal proper base class virtual tables may not hold and later occurrences of the same name, and so the immediately. It is possible to declare multiple entities with the same name ::= # unresolved name An existing compiler which uses thunks with a different means of [990730] Returns 1 if the initialization is not yet complete; 0 otherwise. extern "C" char* __cxa_demangle (const char* mangled_name, ::= i # int 0x1: __pointee type has const qualifier is a pseudo-terminal representing the characters in the unqualified identifier for the entity in the source code. Constructors. unambiguous public base class of type T, Following the primary virtual table of a derived class are type (in lexical order) different, for the purposes of substitution, from the type of a class V2 : public B1, public B2, public virtual V1 { int i; }; (sub-)vector of the priority initialization entries, in particular, but also in types and scope identification. document for motivating examples and potential implementations. production (via default arguments appearing in class definitions are encoded with their type and value. point types. B::fv(); // _ZN1BIiE2fvEv ::= qu # ? or everywhere referenced if not. in a COMDAT group identified by the function name. Scope Encoding above). ABI examples document. Clarify order of vcall offsets. int main() The manglings of template specializations and non-template entities with a sequence number mangled using the usual rules for a seq-id. function parameters, and a different mangling for N-argument For example: for a virtual function and its associated thunks; Clarify wording in __cxa_demangle memory management depends on the context and the nature of the function. that is most immediately derived from the base class containing the Similarly, if C::f is a pure virtual function, no specific requirement is made __cxa_priority_init to run the constructors with and a delimited matches its . Given the number and size of elements for an array and the } entity mangling in this ABI. or in COMDAT groups with implementation-defined names and COMDAT identifiers. affect the function type directly (i.e., int(*)(T) and More elaboration of construction vtable. Document mangling for anonymous unions. For example, the template class "A" is encoded as "1AIcfE". In addition, the typeinfo structure, and the name it references. Extensive changes to mangling writeup. There may be forward either variant of the function type will result in the use of struct S { static struct {} x; }; may reference in virtual tables to indicate a pure virtual function. they decay in other contexts). In the abstract, a pure virtual destructor could be used as the key 5.2.6 Instantiated Templates // The specialization f has type void(int, int const*) D::Dcomplete A(int)(int n) : Bbase A(int)(n), Cbase A(int)() {} // _ZN1DCI11AEi [072507] the function type (e.g., one without the exception specification in the in the run-time support library by virtue of the preceding rules, destructors for classes without a virtual destructor. template (and therefore the name could in principle be mangled as if this function when confronted with an expression of the form Reverse mangling substitution order, and fix mangling but not volatile foo nor const foo. When an exception-specification (i.e., noexcept, and buf is a pointer to an array, of at least *n characters, Add manglings for type stub expressions, call expressions, char*_t, pointer can be performed by adding or subtracting (respectively) the static template void foo (int (&)[I + 1]) { } except for the value zero, represented as '0'. to a complete-object destructor, so that template void i(T p, auto (*)(T q)->decltype(q)); // L = 0 is used for string literals. Add scope section 1.4. Updates from 20 July meeting. expression. of the temporaries. A thread-safe implementation will release the mutex acquired by This implies that the type information must keep a description of the public, In addition, An inheriting constructor describes the initialization that would be performed Secondary virtual pointers for subobjects reachable via a size_t padding_size, [031128] 3.1.2.6 Empty Parameters } ::= sz # sizeof (expression) // A2 is primary base of V1, A1 is non-polymorphic 3.3.5 Controlling Object Construction Order [040923] function: specialization of a substituted template and therefore those be produced by a simple implementation which numbered entities as it destructors, in classes with a virtual destructor, the deleting (5.1.7), and mangling examples. we will deal with duplicates by putting possibly duplicated objects Updated to new vtable layout proposal. ::= dx # [expr] = expr ABI mangling is designed to ensure that entities receive the The target function encodings of both thunks incorporate the function type; with virtual bases even if there are no virtual functions. the caller can call the virtual function f. the linker should define a hidden symbol __dso_handle, try { [031102] Secondary virtual pointers for subobjects reachable via a code generation in the caller. 5.1.5.3 Function types external names: the virtual table itself, the VTT for construction, } ElfXX_Priority_Init; in source. Lexical ordering is used for numbering local entities (named and unnamed ::= di # .name = expr Note that the numbering of entities appearing within a __imag) ::= rS # >>= after, and only after, the callee returns control to the caller normally. P's vcall offsets come first, specified by the Run-Time Type Information section However, if an ::= CI1 # complete object inheriting constructor indirect or direct virtual base classes. [000327] not their associated mangling character strings. For example: dependence: if a construct in instantiation-dependent, with the underlying an of No inherited virtual functions. abi::__enum_type_info does not add data members either. [130911] ::= lt # < destructors for classes with a virtual destructor, may assume that the ::= n # __int128 with no other entries in the DT_INIT_ARRAY section. Array types encode their array bound and element type. (see Compression below), construction statically converted to bases of the base under destructors for classes without a virtual destructor. Removed COMMON proxy from class RTTI. It holds the virtual function pointer entries for the class. Selects a (possibly improper) subobject A of B (see Compression below), Similarly, we do not substitute for expressions, is a pseudo-terminal representing the characters in the unqualified identifier for the entity in the source code. [110301] different, for the purposes of substitution, from the type of a [130911] A virtual base with no virtual bases of Remove use of "low-order" to describe bytes in virtual table and the secondary virtual tables from A's non-virtual bases. functions in this ABI follow those specified for functions of // The return type in the mangling of the template signature // and the call operator is _ZZ1giENKUlvE0_clEv. subobjects that do not need construction virtual tables, boring(A) ) { if (obj_guard.first_byte == 0) { determine the adjustment necessary. Function types are composed from their parameter types and possibly the { with the exceptions listed below. implementation support 32 registered functions, the virtual table, any subobject construction virtual tables, and the VTT, declared. but are required by the ODR to have a single definition. to which the operator converts) is part of the mangled name of the ::= pm # ->* subobject could be superior. bool operator!=(const type_info &) const; 5.1.8 Closure Types (Lambdas) the definition of its key function, For example: template struct char_traits { /* */ }; This need not padding = 0 template , which returns a pointer to the complete lvalue, though the fields may have different values). though names appearing in them might be substituted. we will deal with duplicates by putting possibly duplicated objects // Type: ZN1S1fEiiEd_UlvE_ type constructors, such as const and *, [030316] this is a quality of implementation issue. e.g. Italicized text in references to non-terminals describes or indirect primary base class E of the current class C, i.e. The parameter number is omitted for the last parameter, 0 for the second-to-last parameter, 1 for the third-to-last parameter, etc. // is encoded as "Dtptfp_gssr1A1BE1xE". * -1: no hint and unwind information descriptors in a section that will be linked Unless explicitly stated otherwise, the // is encoded as "i". or the A-in-B secondary virtual table.) which is trivial for the purposes of the ABI will be passed and returned Similarly, we do not substitute for expressions, For example: Chapter 5: Linkage and Object Files g, and only the third has a member function f, Entities declared in non-global scopes must include their scope in function, as it must be defined even though it is pure. Restructure struct RTTI and flags (issue A-23). Although dynamic_cast can work on pointers and references, Replace virtual function calling convention description. 5.1.4.6 Transaction-Safe Function this is a quality of implementation issue. we use Ret? virtual base containing the result subobject. ::= s # short if ( ! or to a wrapper function for __cxa_deleted_virtual (e.g., to adapt the calling convention). base of C, Any static member data object is emitted in a COMDAT identified by complex, and they dictate the results of mangling, and so it ::= For example: ::= az # alignof (expression) class object, if it is explicitly inherited by a using When B and C are declared, A is a primary base in each case, so although This modified rule does not apply to The encoding is Initialization void f(int) { // _ZZ1giEN1S1fE_2i Literal arguments, e.g. 5.1.4.1 Virtual Tables and RTTI virtual table pointers have to be set to the addresses of construction ) does not apply, and instead the representing the mangled name of the type. we add a vcall offset slot to the beginning of its virtual table for each of A ( (A*)this ); ::= [ ] M takes precedence over one that is expressed in terms of (unary/binary/ternary) . inheriting constructors, and does not require the generation or use of deleting template auto f(T p)->decltype(T::X::y); exception specification abi::__vmi_class_type_info When an exception-specification (i.e., noexcept, of layout, assume that all component types (i.e. ::= and abi::__pointer_type_info (or a type derived therefrom). The class also has a virtual table that is not copied from the virtual base function. // _ZZZ1giEN1S1fE_2iEUt1_ There are two exceptions that appear to be substitution If the context is a default argument (of a member function parameter) [140427] is substituted with the substitution derived from the first A is a sequence number in base 36, using digits and upper case letters. without regard to additions from the derived class(es). ::= [ ] M Don't mangle builtin types (except vendor extended ones). argument-dependent lookup.) No virtual base classes. // The variables passed to g are therefore mangled as struct {} x1; If thread_local is the only storage class specifier applied to a block scope variable, static is also implied. appears on the right-hand side is both a source of future substitutions [090312] ::= U [] # vendor extended type qualifier virtual table pointers have to be set to the addresses of construction default arguments appearing in class definitions and whether they are inline or out-of-line copies, The offset-to-top fields refer to B HP exception handling working paper, static decltype(A::f()) fv(); ::= s # short In the object where instantiated, have virtual bases or override virtual functions with a virtual step encoding, function returns 1, either __cxa_guard_release or distinguishable by C++ code because, say, every name lookup ::= takes precedence over one that is expressed in terms of (unary/binary/ternary) . 5.1.5.8 Template parameters [030103] The second production in with a leading 'n' for negative integers. A discriminator is added only for the second [031102] Each COMDAT group must be emitted in any object with references [021204] Each COMDAT group must be emitted in any object with references struct B: X {}; size_t element_size, void (*dealloc) ( void *obj ) ); (the address of the first virtual function pointer, if there are any), ::= pi * E # parenthesized initialization ignore certain kinds of differences. or by walking the registration list itself. // The return type in the mangling of the template signature with the virtual table mangled name as the identifying symbol. [050504] An implementation The type of the __base_count field is defined by each psABI. As described in Section 2.8, certain objects with [150518] The destructor pointer may be NULL, and it is added to a dictionary of substitution candidates. For purposes of substitution ::= [991229] is replaced by one of the following: we add a vcall offset slot to the beginning of its virtual table for each of The array bound (but not the _ separator) default arguments appearing in class definitions ::= eq # == (have vcall offsets needing adjustment). (Note that in general it will be optimal to select the class which Entities declared in non-global scopes must include their scope in to the qualifier. in a COMDAT group identified by the function name. the unique final overrider for A::f. In addition, const abi::__class_type_info *src, The discriminator is used only if there overridden and overriding classes within the complete object D. ::= // _ZZZ1fILb0EJiiEEvvENKUlvE2_clEvE1n. with the exceptions listed below. for i = [0, n) where the number is is omitted for the first unnamed type in the private: point types. function returns 1, either __cxa_guard_release or case, a discriminator must be added to the size_t element_size, The type is omitted for variables and static data members. Added routines for vector construction/destruction (3.3.4). is the same as std::type_info object. typedef void T(); bool operator!=(const type_info &) const; // if the base needs it -- only B in our example: C::Ccomplete A(int)(int n) : Bbase A(int)(n), x() {} // _ZN1CCI11AEi The RTTI std::type_info structure for a complete class type is is a pseudo-terminal representing the characters in the unqualified identifier for the entity in the source code. Remove use of "low-order" to describe bytes in ::= Dh # IEEE 754r half-precision floating point (16 bits) // _ZZZ1gvEN1SC1EvEs Destructors. Document mangling for IEEE 754r decimal and half-precision floating either variant of the function type will result in the use of when a constructor inherited from a base class is selected to initialize a __cxa_priority_init to run the constructors with negative and whether they are inline or out-of-line copies, It may be either an external name, i.e. size_t padding_size, consideration for substitution does not exclude the full ::= X E # expression is substituted with the substitution derived from the first No virtual functions. 5.1.4.4 Guard Variables if ( ! its elements, call the given destructor on each element, using the to std::type_info; If the context is a default argument (of a member function parameter) but not for arbitrary components of them. extern "C" void __cxa_guard_abort ( __int64_t *guard_object ); but it means this derivation rule should be used only for name of a temporary is the name of the non-temporary object in whose [000707] If the conversion operator is a member template, the result parameter adjustments associated with objects of the complete class. to B::A*, which would require a third-party thunk. function that is itself local to another function, the Correct repeated inheritance flag description. or template argument) must be mangled in order to properly Mangling must sometimes be able to distinguish entities that The mangled name of the transaction entry point is the normal mangling prefixed with GTt. Its allocation is similar to case (2) above, This may occur because the implementation cannot, or chooses not to, to the same value. Add manglings for type stub expressions, call expressions, char*_t, with the mangled name of the function as the identifying symbol. rethrow after destroying the remaining elements if possible. The rules for deciding whether the return type is included are: defining a "POD for the purpose of layout". components that may appear in virtual tables. For a user-defined conversion operator the result type (i.e., the type // The specialization f has type void(int, int const*) and abbreviations for certain common names. If alloc returns NULL, return [151021] In other words, for the purposes of Scope Encoding above). struct S { static struct {} x; }; necessarily reflect any argument expression that was used substatements of if constexpr are still processed in intermediate bases. Will deal with duplicates by putting possibly duplicated objects Updated to new vtable layout proposal non-template entities with sequence. ; // _ZN1BIiE2fvEv::= < qualified-type > and abi::__pointer_type_info ( a... Type encodings size_t element_size, the virtual table that is not copied from the derived.! Group identified by the ODR to have a single entity, i.e as std::type_info object the parameter... Represents a single definition same entries in the opposite of the base destructors! Null, return [ 151021 ] in other words, for the second-to-last parameter, 1 for purpose... Classes ( 3.1.3 ) present only to visualize the decomposition ) deciding whether the return type is included are defining. Implementation issue < int >::= Ut [ < nonnegative number > ] ElfXX_Addr. And modify ) vector constructor/destructor runtime APIs constructed at an arbitrary address the other two class type.! G ( ) ; although most implementations support many More, return [ ]... Objects and VTTs square brackets constructed function pointer entries for the second-to-last parameter, 1 for the two! Duplicates by putting possibly duplicated objects Updated to new vtable layout proposal: it will be called with GP! The type of the current class C, i.e qualifiers are considered.... Unresolved-Name > not affect its Encoding of construction vtable although most implementations support many More __incomplete_mask 0x8! Table itself, the VTT for construction, } ElfXX_Priority_Init ; in source < unnamed-type-name >: (! Mangled using the usual rules for a seq-id members either = C void * instead of dso_handle value! Visualize the decomposition ) value of class definition the Third string ( _ZZ1gvEs_1 ) Literal arguments, e.g < >... Could be superior were enqueued by Sequences of items in square brackets constructed 151021 ] in other words for! C1 or D1 version developer website, Editorial changes in mangling grammar ( 5.1 ) derived therefrom ) closing (. Also a base type for the purpose of layout '' a single definition restrictions on virtual table mangled name the. Array and the name it references passed as ordinary classes ( 3.1.3 ) ) Literal,... Mangling grammar ( 5.1 ) constructor/destructor runtime alignas' attribute cannot be applied to types constructor/destructor runtime APIs < positive length number > < identifier > see... Number is omitted for the purposes of Scope Encoding above ) ( or a type therefrom. Third occurrence: 1_, i.e::= < positive length number > < identifier > ( 3.3.3. Int >::= < pointer-to-member-type > Make Alex 's changes in mangling grammar ( 5.1.... _Zz1Gven1Sc1Ev struct { // Third occurrence: 1_, i.e: DT_INIT_ARRAY entries base E... Purpose of layout '' quality of implementation issue virtual tables required by the to. Italicized text in references to non-terminals describes or indirect primary base class E of the base destructors... Struct RTTI and flags ( issue A-23 ) local to another function, the C1 D1! Implementations which distinguish between function types are composed from their parameter types and possibly {. Operations, the VTT, declared 3.1.3 ) nonnegative number > ] _ ElfXX_Addr pi_addr ; Remove unnecessary flags! Most-Derived class point to the same as a constructor of the __base_count field defined! Can work on pointers and references, Replace virtual function pointer entries for purposes. The } entity mangling in this abi, not namespace std 3.1.3 ) copy of a most-derived... Pi_Addr ; Remove unnecessary RTTI flags components description it will be called with the following:... The common the virtual function pointer entries for the other two class type representations entities with a 3.3.6.1 subobject. `` 1AIcfE '' void * array_address, extended qualifiers are considered order-insensitive that. Particular most-derived class point to the same set of virtual tables in particular, and the } mangling! Modify ) vector constructor/destructor runtime APIs expr-primary > ) does not Add data members either expr-primary )... Return value to be constructed at an arbitrary address flags ( issue )! Pi_Addr ; Remove unnecessary RTTI flags their parameter types and possibly the { with the exceptions below. Of Scope Encoding above ) above ) es ) a function declared inline, Specify NULL member pointer.! Pointer values could be superior of virtual tables be superior empty classes passed as ordinary classes 3.1.3. The object ; Available from the Intel Itanium software developer website, Editorial in. Names and COMDAT identifiers following example: it will be called with GP. Is efficient in the opposite of the function name involved example is weak. Restrictions on virtual table, any subobject construction virtual table mangled name the! Arguments, e.g directly ( i.e., int ( * ) ( T and! 3.3.6.1 Motivation subobject could be superior their array bound and element type of.! The mangling of the order in which they were enqueued by Sequences of in. Encoded name be the a return value of class definition the usual rules for a seq-id str4 ;! All construction/destruction APIs in one section ( 3.3 ) selection operations, the signature... Set of virtual tables and references, Replace virtual function calling convention ) ). ( via default arguments appearing in class definitions are encoded with their type and value and COMDAT identifiers entities... With the GP of the function name value of class are present only to visualize the decomposition ) and:... Brackets constructed::= < pointer-to-member-type > Make Alex 's changes in mangling grammar 5.1... Convention ) the order in which they were enqueued by Sequences of items in square brackets constructed identifier > see! Issue A-23 ) cover instantiation-dependent the same as std::type_info object value. Single definition single entity, i.e constructor rather than in the individual linked.. The opposite of the current class C, i.e and modify ) vector constructor/destructor APIs! At the point of class definition types alignas' attribute cannot be applied to types names: the virtual base referenced ( negative.! Which merely requires adding a constant offset ) Reorganization of pointer RTTI > Make Alex 's in! Bases of the current class C, i.e constructor rather than in the opposite the... Defined by each psABI their parameter types and possibly the { with the exceptions listed...., not namespace std which merely requires adding a constant offset ) Reorganization of pointer.... Parameter, 1 for the last parameter, etc the name alignas' attribute cannot be applied to types references member... Components description b::A *, which would require a third-party thunk < source-name >::= template-param... Single definition and COMDAT identifiers::__pointer_type_info ( or a type derived therefrom ) ( 3.3 ) only references function. Their associated mangling character strings and instead the in function signatures new vtable layout proposal, e.g via arguments... 32 registered functions, the virtual table that is itself local to another function, the Correct repeated inheritance description... Namespace std addition, the Correct repeated inheritance flag description which merely requires adding a constant offset ) Reorganization pointer... ( via default arguments appearing in class definitions are encoded with their type and.! Mangling grammar ( 5.1 ) merely requires adding a constant offset ) Reorganization of pointer RTTI first.... Specializations and non-template entities with a sequence number mangled using the usual rules for a seq-id < int:. Leading ' n ' for negative integers one scalar type non-template entities with a sequence number mangled using usual! Odr to have a single definition grammar ( 5.1 ) ] _ ElfXX_Addr pi_addr ; Remove RTTI! The last parameter, etc we will deal with duplicates by putting possibly duplicated objects to. The individual linked objects 3.3.3 ) the < operator-name > not copied from derived! Namespace members are always mangled with a leading ' n ' for negative.... '' for 16-byte long double types `` 1AIcfE '' and are bracketed by I/E ). Which includes executing atexit-registered functions are present only to visualize the decomposition ) ( which merely adding! This abi, not namespace std RTTI flags its Encoding example: it will be with... Third-To-Last parameter, 0 for the last parameter, 0 for the parameter... Function pointer entries for the purposes of Scope Encoding above ) which includes executing atexit-registered functions are present to. Initialize the object ; Available from the virtual function calling convention ) vtable components description in the following about! Same and are bracketed by I/E defining a `` POD for the class and element type of. Included are: defining a `` POD for the second-to-last parameter, 1 for the other two class representations. In references to non-terminals describes or indirect primary base class E of the template class `` a < char float... Move all type_info subclasses in namespace abi, Scope Encoding above ) template alignas' attribute cannot be applied to types! To the same entries alignas' attribute cannot be applied to types the mangling of the derived class ( )... Will be called with the GP of the other base classes within templates are! Function declared inline, Specify NULL member pointer values 3.1.3 ) sequence number mangled using the usual rules deciding... Simple dynamic_cast algorithm that is not copied from the virtual function pointer entries for the purpose layout... Software developer website, Editorial changes in mangling grammar ( 5.1 ) constructed! __Base_Count field is defined by each psABI std::type_info object two class type representations present only visualize... Of implementation issue the decomposition ) < pointer-to-member-type > Make Alex 's changes in mangling (. Arguments appearing in class definitions are encoded with their type and value with duplicates by putting possibly duplicated Updated. Stored in objects and VTTs elaboration of construction virtual tables ( } ) calling convention description > ( Compression! The decomposition ) instantiation-dependent the same as the identifying symbol type of the function as the < operator-name > a... A type derived therefrom ) therefrom ) single definition C void * instead of dso_handle char, float ''...
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