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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Binary code compatibility Foreign function interface Language binding Linker dynamic Loader Year itanim. The size of the guard variable is 64 bits.
Virtual call vcall offsets are used to perform pointer adjustment for virtual functions that are declared in a virtual base class or its subobjects and overridden in a class derived from it. Sets the first byte of the guard object to a non-zero value.
Name mangling
The operators are encoded using their usual encoding a two-letter code in most cases. Multiple references to the same string literal produce one string object with one name in the sequence. For further information, consult Chapter 6. The vcall offsets in the secondary virtual table for a virtual base A are ordered as described next. Builtin types are represented by single-letter codes: Other ABI aspects like exception handlingvirtual table layout, structure and stack frame itaniuketc.
The mangled symbols in this example, in the comments below the respective identifier name, are those produced by the GNU GCC 3. If the return types are different, they are both pointer-to-class types, or both reference-to-class types. Note that the above exclusion of function and operator names from consideration for substitution does not exclude the full function entity, i.
The case mangling, especially, is a common issue that must be dealt with in order to call Fortran libraries such as LAPACK from other languages such as C.
Spaces are to be ignored. Floating-point literals are encoded agi a fixed-length lowercase hexadecimal string corresponding to the internal representation IEEE on Itaniumhigh-order bytes first, without leading zeroes.
Similarly, an array type is not a POD for the purpose of layout if the element type of the array is not a POD for the purpose of layout. Any indirect primary base class E of the current class C, i.
Itanium C++ ABI
The mangling of such unnamed types defined in namespace scope is generally unspecified because they do not have to match across translation units. A more efficient implementation would be to emit all of the thunks immediately before the non-adjusting entry point to the function.
When a class is used as a virtual base, we add a vcall offset slot to the beginning of its virtual table for each of the virtual functions it provides, whether in its primary or secondary virtual tables. On Itanium, the associated NaT bit must not be itnium.
Application binary interface – Wikipedia
A complete ABI, such as the Intel Binary Compatibility Standard iBCS[1] allows a program from one operating system supporting that ABI to run without modifications on any other such system, provided that necessary shared libraries are present, and similar prerequisites are fulfilled.
Views Read Edit View history. The constructor for the complete class passes to each proper base class constructor a pointer to the appropriate place in the VTT where the proper base class constructor can find its set of virtual tables. An instantiation of a function template or member function template is emitted in any object where its symbol is referenced non-inlinein a COMDAT group identified by the function name. We add one pointer to the std:: The standard guarantees If the above listing of vcall offsets includes more than one for a particular virtual function signature, only the first one closest to the virtual table address point is allocated.
So, compiling the following java program. If a class has a non-virtual destructor, and a deleting destructor is emitted for that class, the deleting destructor must correctly handle the case that the this pointer is NULL.
This page was last edited on 17 Juneat If the conversion operator is a member template, the result type will appear before the template parameters. In particular, we make substitutions for prefixes of qualified names, but not for arbitrary components of them. An implementation shall place its standard support library in a DSO named libcxa.
Combine vtable content and order sections; clarify ordering.
Replication saves two ‘this’ adjustments for itnium virtual call to an overridden function originally introduced by a non-primary proper base class. Only non-virtual proper base classes.
E delimiters unless either followed by more than one additional composite name component, or preceded by CV-qualifiers for a member function. Note that a vtable has offset-to-top and RTTr entries for classes with virtual bases even if there are no virtual functions.
It is possible to have nested function scopes, e. Retrieved from ” https:
