CbC/CbC_gcc: libiberty/obstacks.texi comparison

comparison libiberty/obstacks.texi @ 111:04ced10e8804

gcc 7

author	kono
date	Fri, 27 Oct 2017 22:46:09 +0900
parents	a06113de4d67
children

comparison

equal deleted inserted replaced

-:561a7518be6b
+:04ced10e8804
-@node Obstacks,Licenses,Functions,Top
+@node Obstacks
-@chapter Obstacks
+@subsection Obstacks
 @cindex obstacks
 An @dfn{obstack} is a pool of memory containing a stack of objects.  You
 can create any number of separate obstacks, and then allocate objects in
 specified obstacks.  Within each obstack, the last object allocated must
 are implemented with macros, so allocation is usually very fast as long as
 the objects are usually small.  And the only space overhead per object is
 the padding needed to start each object on a suitable boundary.
 @menu
-* Creating Obstacks::           How to declare an obstack in your program.
+* Creating Obstacks::		How to declare an obstack in your program.
-* Preparing for Obstacks::      Preparations needed before you can
+* Preparing for Obstacks::	Preparations needed before you can
-use obstacks.
+				 use obstacks.
 * Allocation in an Obstack::    Allocating objects in an obstack.
 * Freeing Obstack Objects::     Freeing objects in an obstack.
-* Obstack Functions::           The obstack functions are both
+* Obstack Functions::		The obstack functions are really macros.
-functions and macros.
 * Growing Objects::             Making an object bigger by stages.
-* Extra Fast Growing::          Extra-high-efficiency (though more
+* Extra Fast Growing::		Extra-high-efficiency (though more
-complicated) growing objects.
+				 complicated) growing objects.
 * Status of an Obstack::        Inquiries about the status of an obstack.
 * Obstacks Data Alignment::     Controlling alignment of objects in obstacks.
 * Obstack Chunks::              How obstacks obtain and release chunks;
-efficiency considerations.
+				 efficiency considerations.
 * Summary of Obstacks::
 @end menu
 @node Creating Obstacks
-@section Creating Obstacks
+@subsubsection Creating Obstacks
 The utilities for manipulating obstacks are declared in the header
 file @file{obstack.h}.
 @pindex obstack.h
 @deftp {Data Type} {struct obstack}
 An obstack is represented by a data structure of type @code{struct
 obstack}.  This structure has a small fixed size; it records the status
 of the obstack and how to find the space in which objects are allocated.
 It does not contain any of the objects themselves.  You should not try
-to access the contents of the structure directly; use only the functions
+to access the contents of the structure directly; use only the macros
 described in this chapter.
 @end deftp
 You can declare variables of type @code{struct obstack} and use them as
 obstacks, or you can allocate obstacks dynamically like any other kind
 of object.  Dynamic allocation of obstacks allows your program to have a
 variable number of different stacks.  (You can even allocate an
 obstack structure in another obstack, but this is rarely useful.)
-All the functions that work with obstacks require you to specify which
+All the macros that work with obstacks require you to specify which
 obstack to use.  You do this with a pointer of type @code{struct obstack
 *}.  In the following, we often say ``an obstack'' when strictly
 speaking the object at hand is such a pointer.
 The objects in the obstack are packed into large blocks called
 get a chunk.  Usually you supply a function which uses @code{malloc}
 directly or indirectly.  You must also supply a function to free a chunk.
 These matters are described in the following section.
 @node Preparing for Obstacks
-@section Preparing for Using Obstacks
+@subsubsection Preparing for Using Obstacks
-Each source file in which you plan to use the obstack functions
+Each source file in which you plan to use obstacks
 must include the header file @file{obstack.h}, like this:
 @smallexample
 #include <obstack.h>
 @end smallexample
 @findex obstack_chunk_alloc
 @findex obstack_chunk_free
 Also, if the source file uses the macro @code{obstack_init}, it must
-declare or define two functions or macros that will be called by the
+declare or define two macros that will be called by the
 obstack library.  One, @code{obstack_chunk_alloc}, is used to allocate
 the chunks of memory into which objects are packed.  The other,
 @code{obstack_chunk_free}, is used to return chunks when the objects in
 them are freed.  These macros should appear before any use of obstacks
 in the source file.
 using obstacks is faster because @code{malloc} is called less often, for
 larger blocks of memory.  @xref{Obstack Chunks}, for full details.
 At run time, before the program can use a @code{struct obstack} object
 as an obstack, it must initialize the obstack by calling
-@code{obstack_init}.
+@code{obstack_init} or one of its variants, @code{obstack_begin},
+@code{obstack_specify_allocation}, or
+@code{obstack_specify_allocation_with_arg}.
 @comment obstack.h
 @comment GNU
 @deftypefun int obstack_init (struct obstack *@var{obstack-ptr})
 Initialize obstack @var{obstack-ptr} for allocation of objects.  This
-function calls the obstack's @code{obstack_chunk_alloc} function.  If
+macro calls the obstack's @code{obstack_chunk_alloc} function.  If
 allocation of memory fails, the function pointed to by
 @code{obstack_alloc_failed_handler} is called.  The @code{obstack_init}
-function always returns 1 (Compatibility notice: Former versions of
+macro always returns 1 (Compatibility notice: Former versions of
 obstack returned 0 if allocation failed).
 @end deftypefun
 Here are two examples of how to allocate the space for an obstack and
 initialize it.  First, an obstack that is a static variable:
 struct obstack *myobstack_ptr
 = (struct obstack *) xmalloc (sizeof (struct obstack));
 obstack_init (myobstack_ptr);
 @end smallexample
+@comment obstack.h
+@comment GNU
+@deftypefun int obstack_begin (struct obstack *@var{obstack-ptr}, size_t chunk_size)
+Like @code{obstack_init}, but specify chunks to be at least
+@var{chunk_size} bytes in size.
+@end deftypefun
+@comment obstack.h
+@comment GNU
+@deftypefun int obstack_specify_allocation (struct obstack *@var{obstack-ptr}, size_t chunk_size, size_t alignment, void *(*chunkfun) (size_t), void (*freefun) (void *))
+Like @code{obstack_init}, specifying chunk size, chunk
+alignment, and memory allocation functions.  A @var{chunk_size} or
+@var{alignment} of zero results in the default size or alignment
+respectively being used.
+@end deftypefun
+@comment obstack.h
+@comment GNU
+@deftypefun int obstack_specify_allocation_with_arg (struct obstack *@var{obstack-ptr}, size_t chunk_size, size_t alignment, void *(*chunkfun) (void *, size_t), void (*freefun) (void *, void *), void *arg)
+Like @code{obstack_specify_allocation}, but specifying memory
+allocation functions that take an extra first argument, @var{arg}.
+@end deftypefun
 @comment obstack.h
 @comment GNU
 @defvar obstack_alloc_failed_handler
 The value of this variable is a pointer to a function that
 @end smallexample
 @end defvar
 @node Allocation in an Obstack
-@section Allocation in an Obstack
+@subsubsection Allocation in an Obstack
 @cindex allocation (obstacks)
 The most direct way to allocate an object in an obstack is with
 @code{obstack_alloc}, which is invoked almost like @code{malloc}.
 @comment obstack.h
 @comment GNU
-@deftypefun {void *} obstack_alloc (struct obstack *@var{obstack-ptr}, int @var{size})
+@deftypefun {void *} obstack_alloc (struct obstack *@var{obstack-ptr}, size_t @var{size})
 This allocates an uninitialized block of @var{size} bytes in an obstack
 and returns its address.  Here @var{obstack-ptr} specifies which obstack
 to allocate the block in; it is the address of the @code{struct obstack}
-object which represents the obstack.  Each obstack function or macro
+object which represents the obstack.  Each obstack macro
 requires you to specify an @var{obstack-ptr} as the first argument.
-This function calls the obstack's @code{obstack_chunk_alloc} function if
+This macro calls the obstack's @code{obstack_chunk_alloc} function if
 it needs to allocate a new chunk of memory; it calls
 @code{obstack_alloc_failed_handler} if allocation of memory by
 @code{obstack_chunk_alloc} failed.
 @end deftypefun
 memcpy (s, string, len);
 return s;
 @}
 @end smallexample
-To allocate a block with specified contents, use the function
+To allocate a block with specified contents, use the macro @code{obstack_copy}.
-@code{obstack_copy}, declared like this:
+@comment obstack.h
-@comment obstack.h
+@comment GNU
-@comment GNU
+@deftypefun {void *} obstack_copy (struct obstack *@var{obstack-ptr}, void *@var{address}, size_t @var{size})
-@deftypefun {void *} obstack_copy (struct obstack *@var{obstack-ptr}, void *@var{address}, int @var{size})
 This allocates a block and initializes it by copying @var{size}
 bytes of data starting at @var{address}.  It calls
 @code{obstack_alloc_failed_handler} if allocation of memory by
 @code{obstack_chunk_alloc} failed.
 @end deftypefun
 @comment obstack.h
 @comment GNU
-@deftypefun {void *} obstack_copy0 (struct obstack *@var{obstack-ptr}, void *@var{address}, int @var{size})
+@deftypefun {void *} obstack_copy0 (struct obstack *@var{obstack-ptr}, void *@var{address}, size_t @var{size})
 Like @code{obstack_copy}, but appends an extra byte containing a null
 character.  This extra byte is not counted in the argument @var{size}.
 @end deftypefun
-The @code{obstack_copy0} function is convenient for copying a sequence
+The @code{obstack_copy0} macro is convenient for copying a sequence
 of characters into an obstack as a null-terminated string.  Here is an
 example of its use:
 @smallexample
 char *
-obstack_savestring (char *addr, int size)
+obstack_savestring (char *addr, size_t size)
 @{
 return obstack_copy0 (&myobstack, addr, size);
 @}
 @end smallexample
 @noindent
 Contrast this with the previous example of @code{savestring} using
 @code{malloc} (@pxref{Basic Allocation, , , libc, The GNU C Library Reference Manual}).
 @node Freeing Obstack Objects
-@section Freeing Objects in an Obstack
+@subsubsection Freeing Objects in an Obstack
 @cindex freeing (obstacks)
-To free an object allocated in an obstack, use the function
+To free an object allocated in an obstack, use the macro
 @code{obstack_free}.  Since the obstack is a stack of objects, freeing
 one object automatically frees all other objects allocated more recently
 in the same obstack.
 @comment obstack.h
 the objects in a chunk become free, the obstack library automatically
 frees the chunk (@pxref{Preparing for Obstacks}).  Then other
 obstacks, or non-obstack allocation, can reuse the space of the chunk.
 @node Obstack Functions
-@section Obstack Functions and Macros
+@subsubsection Obstack Functions and Macros
 @cindex macros
-The interfaces for using obstacks may be defined either as functions or
+The interfaces for using obstacks are shown here as functions to
-as macros, depending on the compiler.  The obstack facility works with
+specify the return type and argument types, but they are really
-all C compilers, including both @w{ISO C} and traditional C, but there are
+defined as macros.  This means that the arguments don't actually have
-precautions you must take if you plan to use compilers other than GNU C.
+types, but they generally behave as if they have the types shown.
+You can call these macros like functions, but you cannot use them in
-If you are using an old-fashioned @w{non-ISO C} compiler, all the obstack
+any other way (for example, you cannot take their address).
-``functions'' are actually defined only as macros.  You can call these
-macros like functions, but you cannot use them in any other way (for
-example, you cannot take their address).
 Calling the macros requires a special precaution: namely, the first
 operand (the obstack pointer) may not contain any side effects, because
 it may be computed more than once.  For example, if you write this:
 you will find that @code{get_obstack} may be called several times.
 If you use @code{*obstack_list_ptr++} as the obstack pointer argument,
 you will get very strange results since the incrementation may occur
 several times.
-In @w{ISO C}, each function has both a macro definition and a function
-definition.  The function definition is used if you take the address of the
-function without calling it.  An ordinary call uses the macro definition by
-default, but you can request the function definition instead by writing the
-function name in parentheses, as shown here:
-@smallexample
-char *x;
-void *(*funcp) ();
-/* @r{Use the macro}.  */
-x = (char *) obstack_alloc (obptr, size);
-/* @r{Call the function}.  */
-x = (char *) (obstack_alloc) (obptr, size);
-/* @r{Take the address of the function}.  */
-funcp = obstack_alloc;
-@end smallexample
-@noindent
-This is the same situation that exists in @w{ISO C} for the standard library
-functions.  @xref{Macro Definitions, , , libc, The GNU C Library Reference Manual}.
-@strong{Warning:} When you do use the macros, you must observe the
-precaution of avoiding side effects in the first operand, even in @w{ISO C}.
 If you use the GNU C compiler, this precaution is not necessary, because
 various language extensions in GNU C permit defining the macros so as to
 compute each argument only once.
+Note that arguments other than the first will only be evaluated once,
+even when not using GNU C.
+@code{obstack.h} does declare a number of functions,
+@code{_obstack_begin}, @code{_obstack_begin_1},
+@code{_obstack_newchunk}, @code{_obstack_free}, and
+@code{_obstack_memory_used}.  You should not call these directly.
 @node Growing Objects
-@section Growing Objects
+@subsubsection Growing Objects
 @cindex growing objects (in obstacks)
 @cindex changing the size of a block (obstacks)
 Because memory in obstack chunks is used sequentially, it is possible to
 build up an object step by step, adding one or more bytes at a time to the
 end of the object.  With this technique, you do not need to know how much
 data you will put in the object until you come to the end of it.  We call
-this the technique of @dfn{growing objects}.  The special functions
+this the technique of @dfn{growing objects}.  The special macros
 for adding data to the growing object are described in this section.
 You don't need to do anything special when you start to grow an object.
-Using one of the functions to add data to the object automatically
+Using one of the macros to add data to the object automatically
 starts it.  However, it is necessary to say explicitly when the object is
-finished.  This is done with the function @code{obstack_finish}.
+finished.  This is done with @code{obstack_finish}.
 The actual address of the object thus built up is not known until the
 object is finished.  Until then, it always remains possible that you will
 add so much data that the object must be copied into a new chunk.
 ordinary allocation of another object.  If you try to do so, the space
 already added to the growing object will become part of the other object.
 @comment obstack.h
 @comment GNU
-@deftypefun void obstack_blank (struct obstack *@var{obstack-ptr}, int @var{size})
+@deftypefun void obstack_blank (struct obstack *@var{obstack-ptr}, size_t @var{size})
-The most basic function for adding to a growing object is
+The most basic macro for adding to a growing object is
 @code{obstack_blank}, which adds space without initializing it.
 @end deftypefun
 @comment obstack.h
 @comment GNU
-@deftypefun void obstack_grow (struct obstack *@var{obstack-ptr}, void *@var{data}, int @var{size})
+@deftypefun void obstack_grow (struct obstack *@var{obstack-ptr}, void *@var{data}, size_t @var{size})
 To add a block of initialized space, use @code{obstack_grow}, which is
 the growing-object analogue of @code{obstack_copy}.  It adds @var{size}
 bytes of data to the growing object, copying the contents from
 @var{data}.
 @end deftypefun
 @comment obstack.h
 @comment GNU
-@deftypefun void obstack_grow0 (struct obstack *@var{obstack-ptr}, void *@var{data}, int @var{size})
+@deftypefun void obstack_grow0 (struct obstack *@var{obstack-ptr}, void *@var{data}, size_t @var{size})
 This is the growing-object analogue of @code{obstack_copy0}.  It adds
 @var{size} bytes copied from @var{data}, followed by an additional null
 character.
 @end deftypefun
 @comment obstack.h
 @comment GNU
 @deftypefun void obstack_1grow (struct obstack *@var{obstack-ptr}, char @var{c})
-To add one character at a time, use the function @code{obstack_1grow}.
+To add one character at a time, use @code{obstack_1grow}.
 It adds a single byte containing @var{c} to the growing object.
 @end deftypefun
 @comment obstack.h
 @comment GNU
 @deftypefun void obstack_ptr_grow (struct obstack *@var{obstack-ptr}, void *@var{data})
-Adding the value of a pointer one can use the function
+Adding the value of a pointer one can use
 @code{obstack_ptr_grow}.  It adds @code{sizeof (void *)} bytes
 containing the value of @var{data}.
 @end deftypefun
 @comment obstack.h
 @comment GNU
 @deftypefun void obstack_int_grow (struct obstack *@var{obstack-ptr}, int @var{data})
-A single value of type @code{int} can be added by using the
+A single value of type @code{int} can be added by using
-@code{obstack_int_grow} function.  It adds @code{sizeof (int)} bytes to
+@code{obstack_int_grow}.  It adds @code{sizeof (int)} bytes to
 the growing object and initializes them with the value of @var{data}.
 @end deftypefun
 @comment obstack.h
 @comment GNU
 @deftypefun {void *} obstack_finish (struct obstack *@var{obstack-ptr})
-When you are finished growing the object, use the function
+When you are finished growing the object, use
 @code{obstack_finish} to close it off and return its final address.
 Once you have finished the object, the obstack is available for ordinary
 allocation or for growing another object.
-This function can return a null pointer under the same conditions as
-@code{obstack_alloc} (@pxref{Allocation in an Obstack}).
 @end deftypefun
 When you build an object by growing it, you will probably need to know
 afterward how long it became.  You need not keep track of this as you grow
-the object, because you can find out the length from the obstack just
+the object, because you can find out the length from the obstack
-before finishing the object with the function @code{obstack_object_size},
+with @code{obstack_object_size}, before finishing the object.
-declared as follows:
+@comment obstack.h
-@comment obstack.h
+@comment GNU
-@comment GNU
+@deftypefun size_t obstack_object_size (struct obstack *@var{obstack-ptr})
-@deftypefun int obstack_object_size (struct obstack *@var{obstack-ptr})
+This macro returns the current size of the growing object, in bytes.
-This function returns the current size of the growing object, in bytes.
+Remember to call @code{obstack_object_size} @emph{before} finishing the object.
-Remember to call this function @emph{before} finishing the object.
 After it is finished, @code{obstack_object_size} will return zero.
 @end deftypefun
 If you have started growing an object and wish to cancel it, you should
 finish it and then free it, like this:
 @end smallexample
 @noindent
 This has no effect if no object was growing.
-@cindex shrinking objects
-You can use @code{obstack_blank} with a negative size argument to make
-the current object smaller.  Just don't try to shrink it beyond zero
-length---there's no telling what will happen if you do that.
 @node Extra Fast Growing
-@section Extra Fast Growing Objects
+@subsubsection Extra Fast Growing Objects
 @cindex efficiency and obstacks
-The usual functions for growing objects incur overhead for checking
+The usual macros for growing objects incur overhead for checking
 whether there is room for the new growth in the current chunk.  If you
 are frequently constructing objects in small steps of growth, this
 overhead can be significant.
 You can reduce the overhead by using special ``fast growth''
-functions that grow the object without checking.  In order to have a
+macros that grow the object without checking.  In order to have a
 robust program, you must do the checking yourself.  If you do this checking
 in the simplest way each time you are about to add data to the object, you
 have not saved anything, because that is what the ordinary growth
-functions do.  But if you can arrange to check less often, or check
+macros do.  But if you can arrange to check less often, or check
 more efficiently, then you make the program faster.
-The function @code{obstack_room} returns the amount of room available
+@code{obstack_room} returns the amount of room available
-in the current chunk.  It is declared as follows:
+in the current chunk.
 @comment obstack.h
 @comment GNU
-@deftypefun int obstack_room (struct obstack *@var{obstack-ptr})
+@deftypefun size_t obstack_room (struct obstack *@var{obstack-ptr})
 This returns the number of bytes that can be added safely to the current
 growing object (or to an object about to be started) in obstack
-@var{obstack} using the fast growth functions.
+@var{obstack} using the fast growth macros.
 @end deftypefun
-While you know there is room, you can use these fast growth functions
+While you know there is room, you can use these fast growth macros
 for adding data to a growing object:
 @comment obstack.h
 @comment GNU
 @deftypefun void obstack_1grow_fast (struct obstack *@var{obstack-ptr}, char @var{c})
-The function @code{obstack_1grow_fast} adds one byte containing the
+@code{obstack_1grow_fast} adds one byte containing the
 character @var{c} to the growing object in obstack @var{obstack-ptr}.
 @end deftypefun
 @comment obstack.h
 @comment GNU
 @deftypefun void obstack_ptr_grow_fast (struct obstack *@var{obstack-ptr}, void *@var{data})
-The function @code{obstack_ptr_grow_fast} adds @code{sizeof (void *)}
+@code{obstack_ptr_grow_fast} adds @code{sizeof (void *)}
 bytes containing the value of @var{data} to the growing object in
 obstack @var{obstack-ptr}.
 @end deftypefun
 @comment obstack.h
 @comment GNU
 @deftypefun void obstack_int_grow_fast (struct obstack *@var{obstack-ptr}, int @var{data})
-The function @code{obstack_int_grow_fast} adds @code{sizeof (int)} bytes
+@code{obstack_int_grow_fast} adds @code{sizeof (int)} bytes
 containing the value of @var{data} to the growing object in obstack
 @var{obstack-ptr}.
 @end deftypefun
 @comment obstack.h
 @comment GNU
-@deftypefun void obstack_blank_fast (struct obstack *@var{obstack-ptr}, int @var{size})
+@deftypefun void obstack_blank_fast (struct obstack *@var{obstack-ptr}, size_t @var{size})
-The function @code{obstack_blank_fast} adds @var{size} bytes to the
+@code{obstack_blank_fast} adds @var{size} bytes to the
 growing object in obstack @var{obstack-ptr} without initializing them.
 @end deftypefun
 When you check for space using @code{obstack_room} and there is not
-enough room for what you want to add, the fast growth functions
+enough room for what you want to add, the fast growth macros
 are not safe.  In this case, simply use the corresponding ordinary
-growth function instead.  Very soon this will copy the object to a
+growth macro instead.  Very soon this will copy the object to a
 new chunk; then there will be lots of room available again.
-So, each time you use an ordinary growth function, check afterward for
+So, each time you use an ordinary growth macro, check afterward for
 sufficient space using @code{obstack_room}.  Once the object is copied
 to a new chunk, there will be plenty of space again, so the program will
-start using the fast growth functions again.
+start using the fast growth macros again.
 Here is an example:
 @smallexample
 @group
 void
-add_string (struct obstack *obstack, const char *ptr, int len)
+add_string (struct obstack *obstack, const char *ptr, size_t len)
 @{
 while (len > 0)
 @{
-int room = obstack_room (obstack);
+size_t room = obstack_room (obstack);
 if (room == 0)
 @{
-/* @r{Not enough room. Add one character slowly,}
+/* @r{Not enough room.  Add one character slowly,}
 @r{which may copy to a new chunk and make room.}  */
 obstack_1grow (obstack, *ptr++);
 len--;
 @}
 else
 @}
 @}
 @end group
 @end smallexample
+@cindex shrinking objects
+You can use @code{obstack_blank_fast} with a ``negative'' size
+argument to make the current object smaller.  Just don't try to shrink
+it beyond zero length---there's no telling what will happen if you do
+that.  Earlier versions of obstacks allowed you to use
+@code{obstack_blank} to shrink objects.  This will no longer work.
 @node Status of an Obstack
-@section Status of an Obstack
+@subsubsection Status of an Obstack
 @cindex obstack status
 @cindex status of obstack
-Here are functions that provide information on the current status of
+Here are macros that provide information on the current status of
 allocation in an obstack.  You can use them to learn about an object while
 still growing it.
 @comment obstack.h
 @comment GNU
 @deftypefun {void *} obstack_base (struct obstack *@var{obstack-ptr})
-This function returns the tentative address of the beginning of the
+This macro returns the tentative address of the beginning of the
 currently growing object in @var{obstack-ptr}.  If you finish the object
 immediately, it will have that address.  If you make it larger first, it
 may outgrow the current chunk---then its address will change!
 If no object is growing, this value says where the next object you
 @end deftypefun
 @comment obstack.h
 @comment GNU
 @deftypefun {void *} obstack_next_free (struct obstack *@var{obstack-ptr})
-This function returns the address of the first free byte in the current
+This macro returns the address of the first free byte in the current
 chunk of obstack @var{obstack-ptr}.  This is the end of the currently
 growing object.  If no object is growing, @code{obstack_next_free}
 returns the same value as @code{obstack_base}.
 @end deftypefun
 @comment obstack.h
 @comment GNU
-@deftypefun int obstack_object_size (struct obstack *@var{obstack-ptr})
+@deftypefun size_t obstack_object_size (struct obstack *@var{obstack-ptr})
-This function returns the size in bytes of the currently growing object.
+This macro returns the size in bytes of the currently growing object.
 This is equivalent to
 @smallexample
-obstack_next_free (@var{obstack-ptr}) - obstack_base (@var{obstack-ptr})
+((size_t) (obstack_next_free (@var{obstack-ptr}) - obstack_base (@var{obstack-ptr})))
 @end smallexample
 @end deftypefun
 @node Obstacks Data Alignment
-@section Alignment of Data in Obstacks
+@subsubsection Alignment of Data in Obstacks
 @cindex alignment (in obstacks)
 Each obstack has an @dfn{alignment boundary}; each object allocated in
 the obstack automatically starts on an address that is a multiple of the
-specified boundary.  By default, this boundary is 4 bytes.
+specified boundary.  By default, this boundary is aligned so that
+the object can hold any type of data.
 To access an obstack's alignment boundary, use the macro
-@code{obstack_alignment_mask}, whose function prototype looks like
+@code{obstack_alignment_mask}.
-this:
+@comment obstack.h
-@comment obstack.h
+@comment GNU
-@comment GNU
+@deftypefn Macro size_t obstack_alignment_mask (struct obstack *@var{obstack-ptr})
-@deftypefn Macro int obstack_alignment_mask (struct obstack *@var{obstack-ptr})
 The value is a bit mask; a bit that is 1 indicates that the corresponding
 bit in the address of an object should be 0.  The mask value should be one
 less than a power of 2; the effect is that all object addresses are
-multiples of that power of 2.  The default value of the mask is 3, so that
+multiples of that power of 2.  The default value of the mask is a value
+that allows aligned objects to hold any type of data: for example, if
+its value is 3, any type of data can be stored at locations whose
 addresses are multiples of 4.  A mask value of 0 means an object can start
 on any multiple of 1 (that is, no alignment is required).
 The expansion of the macro @code{obstack_alignment_mask} is an lvalue,
 so you can alter the mask by assignment.  For example, this statement:
 alignment mask take effect immediately by calling @code{obstack_finish}.
 This will finish a zero-length object and then do proper alignment for
 the next object.
 @node Obstack Chunks
-@section Obstack Chunks
+@subsubsection Obstack Chunks
 @cindex efficiency of chunks
 @cindex chunks
 Obstacks work by allocating space for themselves in large chunks, and
 then parceling out space in the chunks to satisfy your requests.  Chunks
 enough to satisfy many typical requests on the obstack yet short enough
 not to waste too much memory in the portion of the last chunk not yet used.
 @comment obstack.h
 @comment GNU
-@deftypefn Macro int obstack_chunk_size (struct obstack *@var{obstack-ptr})
+@deftypefn Macro size_t obstack_chunk_size (struct obstack *@var{obstack-ptr})
 This returns the chunk size of the given obstack.
 @end deftypefn
 Since this macro expands to an lvalue, you can specify a new chunk size by
 assigning it a new value.  Doing so does not affect the chunks already
 if (obstack_chunk_size (obstack_ptr) < @var{new-chunk-size})
 obstack_chunk_size (obstack_ptr) = @var{new-chunk-size};
 @end smallexample
 @node Summary of Obstacks
-@section Summary of Obstack Functions
+@subsubsection Summary of Obstack Macros
-Here is a summary of all the functions associated with obstacks.  Each
+Here is a summary of all the macros associated with obstacks.  Each
 takes the address of an obstack (@code{struct obstack *}) as its first
 argument.
 @table @code
-@item void obstack_init (struct obstack *@var{obstack-ptr})
+@item int obstack_init (struct obstack *@var{obstack-ptr})
 Initialize use of an obstack.  @xref{Creating Obstacks}.
-@item void *obstack_alloc (struct obstack *@var{obstack-ptr}, int @var{size})
+@item int obstack_begin (struct obstack *@var{obstack-ptr}, size_t chunk_size)
+Initialize use of an obstack, with an initial chunk of
+@var{chunk_size} bytes.
+@item int obstack_specify_allocation (struct obstack *@var{obstack-ptr}, size_t chunk_size, size_t alignment, void *(*chunkfun) (size_t), void (*freefun) (void *))
+Initialize use of an obstack, specifying intial chunk size, chunk
+alignment, and memory allocation functions.
+@item int obstack_specify_allocation_with_arg (struct obstack *@var{obstack-ptr}, size_t chunk_size, size_t alignment, void *(*chunkfun) (void *, size_t), void (*freefun) (void *, void *), void *arg)
+Like @code{obstack_specify_allocation}, but specifying memory
+allocation functions that take an extra first argument, @var{arg}.
+@item void *obstack_alloc (struct obstack *@var{obstack-ptr}, size_t @var{size})
 Allocate an object of @var{size} uninitialized bytes.
 @xref{Allocation in an Obstack}.
-@item void *obstack_copy (struct obstack *@var{obstack-ptr}, void *@var{address}, int @var{size})
+@item void *obstack_copy (struct obstack *@var{obstack-ptr}, void *@var{address}, size_t @var{size})
 Allocate an object of @var{size} bytes, with contents copied from
 @var{address}.  @xref{Allocation in an Obstack}.
-@item void *obstack_copy0 (struct obstack *@var{obstack-ptr}, void *@var{address}, int @var{size})
+@item void *obstack_copy0 (struct obstack *@var{obstack-ptr}, void *@var{address}, size_t @var{size})
 Allocate an object of @var{size}+1 bytes, with @var{size} of them copied
 from @var{address}, followed by a null character at the end.
 @xref{Allocation in an Obstack}.
 @item void obstack_free (struct obstack *@var{obstack-ptr}, void *@var{object})
 Free @var{object} (and everything allocated in the specified obstack
 more recently than @var{object}).  @xref{Freeing Obstack Objects}.
-@item void obstack_blank (struct obstack *@var{obstack-ptr}, int @var{size})
+@item void obstack_blank (struct obstack *@var{obstack-ptr}, size_t @var{size})
 Add @var{size} uninitialized bytes to a growing object.
 @xref{Growing Objects}.
-@item void obstack_grow (struct obstack *@var{obstack-ptr}, void *@var{address}, int @var{size})
+@item void obstack_grow (struct obstack *@var{obstack-ptr}, void *@var{address}, size_t @var{size})
 Add @var{size} bytes, copied from @var{address}, to a growing object.
 @xref{Growing Objects}.
-@item void obstack_grow0 (struct obstack *@var{obstack-ptr}, void *@var{address}, int @var{size})
+@item void obstack_grow0 (struct obstack *@var{obstack-ptr}, void *@var{address}, size_t @var{size})
 Add @var{size} bytes, copied from @var{address}, to a growing object,
 and then add another byte containing a null character.  @xref{Growing
 Objects}.
 @item void obstack_1grow (struct obstack *@var{obstack-ptr}, char @var{data-char})
 @item void *obstack_finish (struct obstack *@var{obstack-ptr})
 Finalize the object that is growing and return its permanent address.
 @xref{Growing Objects}.
-@item int obstack_object_size (struct obstack *@var{obstack-ptr})
+@item size_t obstack_object_size (struct obstack *@var{obstack-ptr})
 Get the current size of the currently growing object.  @xref{Growing
 Objects}.
-@item void obstack_blank_fast (struct obstack *@var{obstack-ptr}, int @var{size})
+@item void obstack_blank_fast (struct obstack *@var{obstack-ptr}, size_t @var{size})
 Add @var{size} uninitialized bytes to a growing object without checking
 that there is enough room.  @xref{Extra Fast Growing}.
 @item void obstack_1grow_fast (struct obstack *@var{obstack-ptr}, char @var{data-char})
 Add one byte containing @var{data-char} to a growing object without
 checking that there is enough room.  @xref{Extra Fast Growing}.
-@item int obstack_room (struct obstack *@var{obstack-ptr})
+@item size_t obstack_room (struct obstack *@var{obstack-ptr})
 Get the amount of room now available for growing the current object.
 @xref{Extra Fast Growing}.
-@item int obstack_alignment_mask (struct obstack *@var{obstack-ptr})
+@item size_t obstack_alignment_mask (struct obstack *@var{obstack-ptr})
 The mask used for aligning the beginning of an object.  This is an
 lvalue.  @xref{Obstacks Data Alignment}.
-@item int obstack_chunk_size (struct obstack *@var{obstack-ptr})
+@item size_t obstack_chunk_size (struct obstack *@var{obstack-ptr})
 The size for allocating chunks.  This is an lvalue.  @xref{Obstack Chunks}.
 @item void *obstack_base (struct obstack *@var{obstack-ptr})
 Tentative starting address of the currently growing object.
 @xref{Status of an Obstack}.

Mercurial > hg > CbC > CbC_gcc

comparison libiberty/obstacks.texi @ 111:04ced10e8804