pragma Eliminate (UNIT_NAME, ENTITY, Source_Location => SOURCE_TRACE) UNIT_NAME ::= IDENTIFIER | SELECTED_COMPONENT, ENTITY ::= IDENTIFIER | SELECTED_COMPONENT, SOURCE_TRACE ::= SOURCE_REFERENCE | SOURCE_REFERENCE LBRACKET SOURCE_TRACE RBRACKET LBRACKET ::= [ RBRACKET ::= ] SOURCE_REFERENCE ::= FILE_NAME : LINE_NUMBER FILE_NAME ::= STRING_LITERAL LINE_NUMBER ::= INTEGER_LITERAL
This pragma indicates that the given entity is not used in the program
to be compiled and built. The entity must be an explicitly declared
subprogram; this includes generic subprogram instances and
subprograms declared in generic package instances.
must be the name of the compilation unit in which the entity is declared.
Source_Location argument is used to resolve overloading
in case more then one callable entity with the same name is declared
in the given compilation unit. Each file name must be the short name of the
source file (with no directory information).
If an entity is not declared in
a generic instantiation (this includes generic subprogram instances),
the source trace includes only one source
reference. If an entity is declared inside a generic instantiation,
its source trace starts from the source location in the instantiation and
ends with the source location of the declaration of the corresponding
entity in the generic
unit. This approach is recursively used in case of nested instantiations:
the leftmost element of the
source trace is the location of the outermost instantiation, the next
element is the location of the next (first nested) instantiation in the
code of the corresponding generic unit, and so on.
The effect of the pragma is to allow the compiler to eliminate the code or data associated with the named entity. Any reference to an eliminated entity outside the compilation unit where it is defined causes a compile-time or link-time error.
The intention of pragma
Eliminate is to allow a program to be compiled
in a system-independent manner, with unused entities eliminated, without
needing to modify the source text. Normally the required set
Eliminate pragmas is constructed automatically using the gnatelim
tool. Elimination of unused entities local to a compilation unit is
automatic, without requiring the use of pragma
Any source file change that removes, splits, or
adds lines may make the set of Eliminate pragmas invalid because their
Source_Location argument values may get out of date.
Pragma Eliminate may be used where the referenced entity is a dispatching operation. In this case all the subprograms to which the given operation can dispatch are considered to be unused (are never called as a result of a direct or a dispatching call).