Discussion and development of the “Itanium” portable C++ ABI used by many major C++ implementations. – Itanium C++ ABI. The Itanium ABI (which GCC uses) may specify these things (as within specifying ranges) Most types’ size and alignment is specified in the Intel System V ABI. Virtual Table Layout General A virtual table (vtable) is a table of information used to dispatch virtual functions, to ac.

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When abo template signatures, a name appearing in the source code cannot always be resolved to a specific entity: Even though its name is unique, g is still mangled: The encoding of closure types is described in a Closure Types Lambdas. It is possible to have nested function scopes, e. Its numbering will be local to the particular argument in which it appears — other default arguments do not affect its encoding.

Both function types are, however, entered the substitution table; subsequent references to either variant of the function type will result in the use of substitutions. Retrieved 13 May Itanihm, given the data address of an array, the non-negative size of prefix padding for the cookie, and the size of its elements, call the given destructor on each element, using the cookie to determine the number of elements, and then delete the space by calling:: At this time, however, the psABI does not attempt to specify the supported C library interfaces.

Itanium C++ ABI

The rules for deciding whether the return type is included are: There is one function pointer entry for each virtual function declared in the class, in declaration order, with any implicitly-defined virtual destructor pair last. Unlike Cfront, unary and binary operators using the same symbol have different encodings. The virtual function overrides a function or functions appearing in the virtual table, but the return type of the overrider is substantively different from the return type of the function aabi already present.

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Retrieved from ” https: All articles with specifically marked weasel-worded phrases Articles with specifically marked weasel-worded phrases from November Each of the methods is assigned itaniuk unique symbol such as an integer. So the mangling must also encode a fixed offset to a non-virtual base, and possibly an offset to a vbase offset in ittanium vtable to get to the virtual base containing the result subobject.

This ABI does not specify that choice.

This function is called after initialization iranium complete. A virtual base with no virtual bases of its own does not require a VTT, but does require a virtual pointer entry in the VTT.

Itanium C++ ABI

Therefore, an implementation should include at least one non-inline virtual function member and define it in the library, to avoid having user code inadvertently preempt the virtual table. Because the different calling conventions are not compatible with one another, compilers mangle symbols with codes detailing which convention should be used to call the specific routine.

Add mangling for alignoffunction parameters, and a different mangling for N-argument function casts. This page was last edited on 17 Juneat September Learn how and when to remove this template message. Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies. This facility only controls construction order within a singled linked object executable or DSO.

Removing that requirement would not be a good idea, as there would then no longer be a way to emit all thunks with the functions they jump to. This difference may in some rare cases lead to unresolved externals when porting such code to 64 bits.

If alloc throws an exception, rethrow the exception. This section needs expansion. For a non-virtual function, this field is a simple function pointer.

The VTT parm isn’t mangled, either. Replication saves two ‘this’ adjustments for each virtual call to an overridden function originally introduced by a non-primary proper base class.

The encoding for a literal of an enumerated type is the encoding of the type name followed by the encoding of the numeric value of the literal in its base integral type which deals with values that don’t have names declared in the type.


VTT is preorder, like everything else. The entries for virtual destructors are actually pairs of entries. An existing compiler which uses thunks with a different means of adjusting the virtual table pointers can be made compliant with this ABI by only adding the vcall offsets — the thunks need not use them. Remove use of “low-order” to describe bytes in guard variables.

This ABI therefore does not specify an encoding for such cases but an implementation must ensure that any internal encoding does not conflict with this ABI. Non-terminals are delimited by diamond braces: The colons in the Objective-C syntax are translated to underscores. Meaning of error indications: Change argument pack mangling. It may be either an external name, i. Application programming interfaces Operating system technology. The operators are encoded using their usual encoding a two-letter code in most cases.

A common aspect of an ABI is the calling conventionwhich determines how data is provided as input to or read as output from computational routines; examples are the x86 calling conventions. In this case, we are creating the A-in-B secondary virtual table. Please help improve this article by adding citations to reliable sources.

Name mangling

There are then three kinds of truly dynamic cast operations: Because the name-mangling systems for such features are not standardized across compilers, few linkers can link object code that was produced by different compilers.

Secondary virtual pointers may ihanium required for base classes that do not require secondary VTTs.

Note that this assumes that the same string literal occurring twice in a given function in fact represents a single entity, i.

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