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Address Class documentation.

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Kevin Buettner 2002-10-17 18:33:36 +00:00
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8
gdb/doc/ChangeLog
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@ -1,3 +1,11 @@
2002-10-17 Kevin Buettner <kevinb@redhat.com>
* gdbint.texinfo (Address Classes): New section.
(Target Conditionals): Document ADDRESS_CLASS_NAME_TO_TYPE_FLAGS,
ADDRESS_CLASS_NAME_TO_TYPE_FLAGS_P, ADDRESS_CLASS_TYPE_FLAGS,
ADDRESS_CLASS_TYPE_FLAGS_P, ADDRESS_CLASS_TYPE_FLAGS_TO_NAME, and
ADDRESS_CLASS_TYPE_FLAGS_TO_NAME_P.
2002-10-11 Klee Dienes <kdienes@apple.com>
* gdb.texinfo (Registers): Mention vector registers as well as

128
gdb/doc/gdbint.texinfo
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@ -2630,6 +2630,91 @@ This function may safely assume that @var{type} is either a pointer or a
C@t{++} reference type.
@end deftypefn
@section Address Classes
@cindex address classes
@cindex DW_AT_byte_size
@cindex DW_AT_address_class
Sometimes information about different kinds of addresses is available
via the debug information. For example, some programming environments
define addresses of several different sizes. If the debug information
distinguishes these kinds of address classes through either the size
info (e.g, @code{DW_AT_byte_size} in @w{DWARF 2}) or through an explicit
address class attribute (e.g, @code{DW_AT_address_class} in @w{DWARF 2}), the
following macros should be defined in order to disambiguate these
types within @value{GDBN} as well as provide the added information to
a @value{GDBN} user when printing type expressions.
@deftypefn {Target Macro} int ADDRESS_CLASS_TYPE_FLAGS (int @var{byte_size}, int @var{dwarf2_addr_class})
Returns the type flags needed to construct a pointer type whose size
is @var{byte_size} and whose address class is @var{dwarf2_addr_class}.
This function is normally called from within a symbol reader. See
@file{dwarf2read.c}.
@end deftypefn
@deftypefn {Target Macro} char *ADDRESS_CLASS_TYPE_FLAGS_TO_NAME (int @var{type_flags})
Given the type flags representing an address class qualifier, return
its name.
@end deftypefn
@deftypefn {Target Macro} int ADDRESS_CLASS_NAME_to_TYPE_FLAGS (int @var{name}, int *var{type_flags_ptr})
Given an address qualifier name, set the @code{int} refererenced by @var{type_flags_ptr} to the type flags
for that address class qualifier.
@end deftypefn
Since the need for address classes is rather rare, none of
the address class macros defined by default. Predicate
macros are provided to detect when they are defined.
Consider a hypothetical architecture in which addresses are normally
32-bits wide, but 16-bit addresses are also supported. Furthermore,
suppose that the @w{DWARF 2} information for this architecture simply
uses a @code{DW_AT_byte_size} value of 2 to indicate the use of one
of these "short" pointers. The following functions could be defined
to implement the address class macros:
@smallexample
somearch_address_class_type_flags (int byte_size,
int dwarf2_addr_class)
{
if (byte_size == 2)
return TYPE_FLAG_ADDRESS_CLASS_1;
else
return 0;
}
static char *
somearch_address_class_type_flags_to_name (int type_flags)
{
if (type_flags & TYPE_FLAG_ADDRESS_CLASS_1)
return "short";
else
return NULL;
}
int
somearch_address_class_name_to_type_flags (char *name,
int *type_flags_ptr)
{
if (strcmp (name, "short") == 0)
{
*type_flags_ptr = TYPE_FLAG_ADDRESS_CLASS_1;
return 1;
}
else
return 0;
}
@end smallexample
The qualifier @code{@@short} is used in @value{GDBN}'s type expressions
to indicate the presence of one of these "short" pointers. E.g, if
the debug information indicates that @code{short_ptr_var} is one of these
short pointers, @value{GDBN} might show the following behavior:
@smallexample
(gdb) ptype short_ptr_var
type = int * @@short
@end smallexample
@section Raw and Virtual Register Representations
@cindex raw register representation
@ -2857,6 +2942,49 @@ boundaries, the processor masks out these bits to generate the actual
address of the instruction. ADDR_BITS_REMOVE should filter out these
bits with an expression such as @code{((addr) & ~3)}.
@item ADDRESS_CLASS_NAME_TO_TYPE_FLAGS (@var{name}, @var{type_flags_ptr})
@findex ADDRESS_CLASS_NAME_TO_TYPE_FLAGS
If @var{name} is a valid address class qualifier name, set the @code{int}
referenced by @var{type_flags_ptr} to the mask representing the qualifier
and return 1. If @var{name} is not a valid address class qualifier name,
return 0.
The value for @var{type_flags_ptr} should be one of
@code{TYPE_FLAG_ADDRESS_CLASS_1}, @code{TYPE_FLAG_ADDRESS_CLASS_2}, or
possibly some combination of these values or'd together.
@xref{Target Architecture Definition, , Address Classes}.
@item ADDRESS_CLASS_NAME_TO_TYPE_FLAGS_P ()
@findex ADDRESS_CLASS_NAME_TO_TYPE_FLAGS_P
Predicate which indicates whether @code{ADDRESS_CLASS_NAME_TO_TYPE_FLAGS}
has been defined.
@item ADDRESS_CLASS_TYPE_FLAGS (@var{byte_size}, @var{dwarf2_addr_class})
@findex ADDRESS_CLASS_TYPE_FLAGS (@var{byte_size}, @var{dwarf2_addr_class})
Given a pointers byte size (as described by the debug information) and
the possible @code{DW_AT_address_class} value, return the type flags
used by @value{GDBN} to represent this address class. The value
returned should be one of @code{TYPE_FLAG_ADDRESS_CLASS_1},
@code{TYPE_FLAG_ADDRESS_CLASS_2}, or possibly some combination of these
values or'd together.
@xref{Target Architecture Definition, , Address Classes}.
@item ADDRESS_CLASS_TYPE_FLAGS_P ()
@findex ADDRESS_CLASS_TYPE_FLAGS_P
Predicate which indicates whether @code{ADDRESS_CLASS_TYPE_FLAGS} has
been defined.
@item ADDRESS_CLASS_TYPE_FLAGS_TO_NAME (@var{type_flags})
@findex ADDRESS_CLASS_TYPE_FLAGS_TO_NAME
Return the name of the address class qualifier associated with the type
flags given by @var{type_flags}.
@item ADDRESS_CLASS_TYPE_FLAGS_TO_NAME_P ()
@findex ADDRESS_CLASS_TYPE_FLAGS_TO_NAME_P
Predicate which indicates whether @code{ADDRESS_CLASS_TYPE_FLAGS_TO_NAME} has
been defined.
@xref{Target Architecture Definition, , Address Classes}.
@item ADDRESS_TO_POINTER (@var{type}, @var{buf}, @var{addr})
@findex ADDRESS_TO_POINTER
Store in @var{buf} a pointer of type @var{type} representing the address