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Changed the @node to use INODE

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This commit is contained in:
Steve Chamberlain
1991-12-19 01:36:25 +00:00
parent 3d60de8161
commit 4a96bc044a
1 changed files with 425 additions and 337 deletions
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750
bfd/section.c
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@ -18,14 +18,16 @@ You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
/*doc* /*
@section Sections SECTION
Sections are supported in BFD in @code{section.c}. Sections
The raw data contained within a BFD is maintained through the section Sections are supported in BFD in <<section.c>>.
abstraction. A single BFD may have any number of sections, and keeps
hold of them by pointing to the first, each one points to the next in The raw data contained within a BFD is maintained through the
the list. section abstraction. A single BFD may have any number of
sections, and keeps hold of them by pointing to the first,
each one points to the next in the list.
@menu @menu
* Section Input:: * Section Input::
@ -34,64 +36,73 @@ the list.
* section prototypes:: * section prototypes::
@end menu @end menu
@node Section Input, Section Output, Sections, Sections INODE
@subsection Section Input Section Input, Section Output, Sections, Sections
When a BFD is opened for reading, the section structures are created
and attached to the BFD.
Each section has a name which describes the section in the outside SUBSECTION
world - for example, @code{a.out} would contain at least three Section Input
sections, called @code{.text}, @code{.data} and @code{.bss}.
When a BFD is opened for reading, the section structures are
created and attached to the BFD.
Each section has a name which describes the section in the
outside world - for example, <<a.out>> would contain at least
three sections, called <<.text>>, <<.data>> and <<.bss>>.
Sometimes a BFD will contain more than the 'natural' number of Sometimes a BFD will contain more than the 'natural' number of
sections. A back end may attach other sections containing constructor sections. A back end may attach other sections containing
data, or an application may add a section (using bfd_make_section) to constructor data, or an application may add a section (using
the sections attached to an already open BFD. For example, the linker bfd_make_section) to the sections attached to an already open
creates a supernumary section @code{COMMON} for each input file's BFD BFD. For example, the linker creates a supernumary section
to hold information about common storage. <<COMMON>> for each input file's BFD to hold information about
common storage.
The raw data is not necessarily read in at the same time as the The raw data is not necessarily read in at the same time as
section descriptor is created. Some targets may leave the data in the section descriptor is created. Some targets may leave the
place until a @code{bfd_get_section_contents} call is made. Other back data in place until a <<bfd_get_section_contents>> call is
ends may read in all the data at once - For example; an S-record file made. Other back ends may read in all the data at once - For
has to be read once to determine the size of the data. An IEEE-695 example; an S-record file has to be read once to determine the
file doesn't contain raw data in sections, but data and relocation size of the data. An IEEE-695 file doesn't contain raw data in
expressions intermixed, so the data area has to be parsed to get out sections, but data and relocation expressions intermixed, so
the data and relocations. the data area has to be parsed to get out the data and
relocations.
@node Section Output, typedef asection, Section Input, Sections INODE
@subsection Section Output Section Output, typedef asection, Section Input, Sections
To write a new object style BFD, the various sections to be written
have to be created. They are attached to the BFD in the same way as
input sections, data is written to the sections using
@code{bfd_set_section_contents}.
The linker uses the fields @code{output_section} and SUBSECTION
@code{output_offset} to create an output file. Section Output
The data to be written comes from input sections attached to the To write a new object style BFD, the various sections to be
output sections. The output section structure can be considered a written have to be created. They are attached to the BFD in
filter for the input section, the output section determines the vma of the same way as input sections, data is written to the
the output data and the name, but the input section determines the sections using <<bfd_set_section_contents>>.
offset into the output section of the data to be written.
Eg to create a section "O", starting at 0x100, 0x123 long, containing two The linker uses the fields <<output_section>> and
subsections, "A" at offset 0x0 (ie at vma 0x100) and "B" at offset <<output_offset>> to create an output file.
0x20 (ie at vma 0x120) the structures would look like:
*+ The data to be written comes from input sections attached to
the output sections. The output section structure can be
considered a filter for the input section, the output section
determines the vma of the output data and the name, but the
input section determines the offset into the output section of
the data to be written.
section name "A" Eg to create a section "O", starting at 0x100, 0x123 long,
output_offset 0x00 containing two subsections, "A" at offset 0x0 (ie at vma
size 0x20 0x100) and "B" at offset 0x20 (ie at vma 0x120) the structures
output_section -----------> section name "O" would look like:
| vma 0x100
section name "B" | size 0x123 | section name "A"
output_offset 0x20 | | output_offset 0x00
size 0x103 | | size 0x20
output_section --------| | output_section -----------> section name "O"
| | vma 0x100
| section name "B" | size 0x123
| output_offset 0x20 |
| size 0x103 |
| output_section --------|
*-
*/ */
@ -100,213 +111,231 @@ subsections, "A" at offset 0x0 (ie at vma 0x100) and "B" at offset
#include "sysdep.h" #include "sysdep.h"
#include "libbfd.h" #include "libbfd.h"
/*
INODE
typedef asection, section prototypes, Section Output, Sections
SUBSECTION
typedef asection
/*doc* SUBSECTION
@node typedef asection, section prototypes, Section Output, Sections typedef asection
@subsection typedef asection
*/
/*proto*
The shape of a section struct: The shape of a section struct:
*+++ CODE_FRAGMENT
.
$typedef struct sec { .typedef struct sec
.{
The name of the section, the name isn't a copy, the pointer is . {* The name of the section, the name isn't a copy, the pointer is
the same as that passed to bfd_make_section. . the same as that passed to bfd_make_section. *}
.
$ CONST char *name; . CONST char *name;
.
The next section in the list belonging to the BFD, or NULL. . {* The next section in the list belonging to the BFD, or NULL. *}
.
$ struct sec *next; . struct sec *next;
.
The field flags contains attributes of the section. Some of these . {* The field flags contains attributes of the section. Some of
flags are read in from the object file, and some are synthesized from . flags are read in from the object file, and some are
other information. . synthesized from other information. *}
.
$flagword flags; . flagword flags;
.
.#define SEC_NO_FLAGS 0x000
$#define SEC_NO_FLAGS 0x000 .
. {* Tells the OS to allocate space for this section when loaded.
Tells the OS to allocate space for this section when loaded. . This would clear for a section containing debug information
This would clear for a section containing debug information only. . only. *}
.
$#define SEC_ALLOC 0x001 .
.#define SEC_ALLOC 0x001
Tells the OS to load the section from the file when loading. . {* Tells the OS to load the section from the file when loading.
This would be clear for a .bss section . This would be clear for a .bss section *}
.
$#define SEC_LOAD 0x002 .#define SEC_LOAD 0x002
. {* The section contains data still to be relocated, so there will
The section contains data still to be relocated, so there will be some . be some relocation information too. *}
relocation information too. .
.#define SEC_RELOC 0x004
$#define SEC_RELOC 0x004 .
. {* Obsolete ? *}
Obsolete ? .
.#define SEC_BALIGN 0x008
$#define SEC_BALIGN 0x008 .
. {* A signal to the OS that the section contains read only
A signal to the OS that the section contains read only data. . data. *}
.#define SEC_READONLY 0x010
$#define SEC_READONLY 0x010 .
. {* The section contains code only. *}
The section contains code only. .
.#define SEC_CODE 0x020
$#define SEC_CODE 0x020 .
. {* The section contains data only. *}
The section contains data only. .
.#define SEC_DATA 0x040
$#define SEC_DATA 0x040 .
. {* The section will reside in ROM. *}
The section will reside in ROM. .
.#define SEC_ROM 0x080
$#define SEC_ROM 0x080 .
. {* The section contains constructor information. This section
The section contains constructor information. This section type is . type is used by the linker to create lists of constructors and
used by the linker to create lists of constructors and destructors . destructors used by <<g++>>. When a back end sees a symbol
used by @code{g++}. When a back end sees a symbol which should be used . which should be used in a constructor list, it creates a new
in a constructor list, it creates a new section for the type of name . section for the type of name (eg <<__CTOR_LIST__>>), attaches
(eg @code{__CTOR_LIST__}), attaches the symbol to it and builds a . the symbol to it and builds a relocation. To build the lists
relocation. To build the lists of constructors, all the linker has to . of constructors, all the linker has to to is catenate all the
to is catenate all the sections called @code{__CTOR_LIST__} and . sections called <<__CTOR_LIST__>> and relocte the data
relocte the data contained within - exactly the operations it would . contained within - exactly the operations it would peform on
peform on standard data. . standard data. *}
.
$#define SEC_CONSTRUCTOR 0x100 .#define SEC_CONSTRUCTOR 0x100
.
The section is a constuctor, and should be placed at the end of the .. . {* The section is a constuctor, and should be placed at the
. end of the . *}
$#define SEC_CONSTRUCTOR_TEXT 0x1100 .
.
$#define SEC_CONSTRUCTOR_DATA 0x2100 .#define SEC_CONSTRUCTOR_TEXT 0x1100
.
$#define SEC_CONSTRUCTOR_BSS 0x3100 .#define SEC_CONSTRUCTOR_DATA 0x2100
.
.#define SEC_CONSTRUCTOR_BSS 0x3100
The section has contents - a bss section could be .
@code{SEC_ALLOC} | @code{SEC_HAS_CONTENTS}, a debug section could be .
@code{SEC_HAS_CONTENTS} . {* The section has contents - a bss section could be
. <<SEC_ALLOC>> | <<SEC_HAS_CONTENTS>>, a debug section could be
$#define SEC_HAS_CONTENTS 0x200 . <<SEC_HAS_CONTENTS>> *}
.
An instruction to the linker not to output sections containing .#define SEC_HAS_CONTENTS 0x200
this flag even if they have information which would normally be written. .
. {* An instruction to the linker not to output sections
$#define SEC_NEVER_LOAD 0x400 . containing this flag even if they have information which
. would normally be written. *}
.
The base address of the section in the address space of the target. .#define SEC_NEVER_LOAD 0x400
.
$ bfd_vma vma; . {* The base address of the section in the address space of the
. target. *}
The size of the section in bytes of the loaded section. This contains .
a value even if the section has no contents (eg, the size of @code{.bss}). . bfd_vma vma;
.
$ bfd_size_type size; . {* The size of the section in bytes of the loaded section. This
. contains a value even if the section has no contents (eg, the
If this section is going to be output, then this value is the . size of <<.bss>>). *}
offset into the output section of the first byte in the input .
section. Eg, if this was going to start at the 100th byte in the . bfd_size_type size;
output section, this value would be 100. .
. {* If this section is going to be output, then this value is the
$ bfd_vma output_offset; . offset into the output section of the first byte in the input
. section. Eg, if this was going to start at the 100th byte in
The output section through which to map on output. . the output section, this value would be 100. *}
.
$ struct sec *output_section; . bfd_vma output_offset;
.
The alignment requirement of the section, as an exponent - eg 3 . {* The output section through which to map on output. *}
aligns to 2^3 (or 8) .
. struct sec *output_section;
$ unsigned int alignment_power; .
. {* The alignment requirement of the section, as an exponent - eg
If an input section, a pointer to a vector of relocation records for . 3 aligns to 2^3 (or 8) *}
the data in this section. .
. unsigned int alignment_power;
$ struct reloc_cache_entry *relocation; .
. {* If an input section, a pointer to a vector of relocation
If an output section, a pointer to a vector of pointers to . records for the data in this section. *}
relocation records for the data in this section. .
. struct reloc_cache_entry *relocation;
$ struct reloc_cache_entry **orelocation; .
. {* If an output section, a pointer to a vector of pointers to
The number of relocation records in one of the above . relocation records for the data in this section. *}
.
$ unsigned reloc_count; . struct reloc_cache_entry **orelocation;
.
Which section is it 0..nth . {* The number of relocation records in one of the above *}
.
$ int index; . unsigned reloc_count;
.
Information below is back end specific - and not always used or . {* Which section is it 0.nth *}
updated .
. int index;
File position of section data .
. {* Information below is back end specific - and not always used
$ file_ptr filepos; . or updated
File position of relocation info .
. File position of section data *}
$ file_ptr rel_filepos; .
. file_ptr filepos;
File position of line data .
. {* File position of relocation info *}
$ file_ptr line_filepos; .
. file_ptr rel_filepos;
Pointer to data for applications .
. {* File position of line data *}
$ PTR userdata; .
. file_ptr line_filepos;
$ struct lang_output_section *otheruserdata; .
. {* Pointer to data for applications *}
Attached line number information .
. PTR userdata;
$ alent *lineno; .
Number of line number records . struct lang_output_section *otheruserdata;
.
$ unsigned int lineno_count; . {* Attached line number information *}
.
When a section is being output, this value changes as more . alent *lineno;
linenumbers are written out .
. {* Number of line number records *}
$ file_ptr moving_line_filepos; .
. unsigned int lineno_count;
what the section number is in the target world .
. {* When a section is being output, this value changes as more
$ unsigned int target_index; . linenumbers are written out *}
.
$ PTR used_by_bfd; . file_ptr moving_line_filepos;
.
If this is a constructor section then here is a list of the . {* what the section number is in the target world *}
relocations created to relocate items within it. .
. unsigned int target_index;
$ struct relent_chain *constructor_chain; .
. PTR used_by_bfd;
The BFD which owns the section. .
. {* If this is a constructor section then here is a list of the
$ bfd *owner; . relocations created to relocate items within it. *}
.
$} asection ; . struct relent_chain *constructor_chain;
.
*--- . {* The BFD which owns the section. *}
.
. bfd *owner;
.
.} asection ;
*/
/*
INODE
section prototypes, , typedef asection, Sections
SUBSECTION
section prototypes
These are the functions exported by the section handling part of
<<libbfd>.
*/
/*
FUNCTION
bfd_get_section_by_name
SYNOPSIS
asection *bfd_get_section_by_name(bfd *abfd, CONST char *name);
DESCRIPTION
Runs through the provided @var{abfd} and returns the
<<asection>> who's name matches that provided, otherwise NULL.
@xref{Sections}, for more information.
*/ */
/*doc*
@node section prototypes, , typedef asection, Sections
@subsection section prototypes
*/
/*proto* bfd_get_section_by_name
Runs through the provided @var{abfd} and returns the @code{asection}
who's name matches that provided, otherwise NULL. @xref{Sections}, for more information.
*; PROTO(asection *, bfd_get_section_by_name,
(bfd *abfd, CONST char *name));
*/
asection * asection *
DEFUN(bfd_get_section_by_name,(abfd, name), DEFUN(bfd_get_section_by_name,(abfd, name),
bfd *abfd AND bfd *abfd AND
@ -320,21 +349,63 @@ DEFUN(bfd_get_section_by_name,(abfd, name),
} }
/*proto* bfd_make_section /*
This function creates a new empty section called @var{name} and attaches it FUNCTION
to the end of the chain of sections for the BFD supplied. An attempt to bfd_make_section_old_way
create a section with a name which is already in use, returns NULL without
changing the section chain. SYNOPSIS
asection *bfd_make_section_old_way(bfd *, CONST char *name);
DESCRIPTION
This function creates a new empty section called @var{name}
and attaches it to the end of the chain of sections for the
BFD supplied. An attempt to create a section with a name which
is already in use, returns its pointer without changing the
section chain.
It has the funny name since this is the way it used to be
before is was rewritten...
Possible errors are: Possible errors are:
@table @code o invalid_operation
@item invalid_operation
If output has already started for this BFD. If output has already started for this BFD.
@item no_memory o no_memory
If obstack alloc fails. If obstack alloc fails.
@end table
*; PROTO(asection *, bfd_make_section, (bfd *, CONST char *name)); */
asection *
DEFUN(bfd_make_section_old_way,(abfd, name),
bfd *abfd AND
CONST char * name)
{
asection *sec = bfd_get_section_by_name(abfd, name);
if (sec == (asection *)NULL)
{
sec = bfd_make_section(abfd, name);
}
return sec;
}
/*
FUNCTION
bfd_make_section
SYNOPSIS
asection * bfd_make_section(bfd *, CONST char *name);
DESCRIPTION
This function creates a new empty section called @var{name}
and attaches it to the end of the chain of sections for the
BFD supplied. An attempt to create a section with a name which
is already in use, returns NULL without changing the section
chain.
Possible errors are:
o invalid_operation - If output has already started for this BFD.
o no_memory - If obstack alloc fails.
*/ */
@ -385,19 +456,23 @@ DEFUN(bfd_make_section,(abfd, name),
} }
/*proto* bfd_set_section_flags /*
Attempts to set the attributes of the section named in the BFD FUNCTION
supplied to the value. Returns true on success, false on error. bfd_set_section_flags
Possible error returns are:
@table @code SYNOPSIS
@item invalid operation boolean bfd_set_section_flags(bfd *, asection *, flagword);
The section cannot have one or more of the attributes requested. For
example, a .bss section in @code{a.out} may not have the DESCRIPTION
@code{SEC_HAS_CONTENTS} field set. Attempts to set the attributes of the section named in the BFD
@end table supplied to the value. Returns true on success, false on
error. Possible error returns are:
o invalid operation
The section cannot have one or more of the attributes
requested. For example, a .bss section in <<a.out>> may not
have the <<SEC_HAS_CONTENTS>> field set.
*; PROTO(boolean, bfd_set_section_flags,
(bfd *, asection *, flagword));
*/ */
boolean boolean
@ -416,27 +491,28 @@ DEFUN(bfd_set_section_flags,(abfd, section, flags),
} }
/*proto* bfd_map_over_sections /*
Calls the provided function @var{func} for each section attached to FUNCTION
the BFD @var{abfd}, passing @var{obj} as an argument. The function bfd_map_over_sections
will be called as if by
@example SYNOPSIS
func(abfd, the_section, obj); void bfd_map_over_sections(bfd *abfd, void (*func)(), PTR obj);
@end example
DESCRIPTION
Calls the provided function @var{func} for each section
attached to the BFD @var{abfd}, passing @var{obj} as an
argument. The function will be called as if by
*; PROTO(void, bfd_map_over_sections, | func(abfd, the_section, obj);
(bfd *abfd, void (*func)(), PTR obj));
This is the prefered method for iterating over sections, an This is the prefered method for iterating over sections, an
alternative would be to use a loop: alternative would be to use a loop:
@example | section *p;
section *p; | for (p = abfd->sections; p != NULL; p = p->next)
for (p = abfd->sections; p != NULL; p = p->next) | func(abfd, p, ...)
func(abfd, p, ...)
@end example
*/ */
/*VARARGS2*/ /*VARARGS2*/
@ -457,18 +533,21 @@ DEFUN(bfd_map_over_sections,(abfd, operation, user_storage),
} }
/*proto* bfd_set_section_size /*
Sets @var{section} to the size @var{val}. If the operation is ok, then FUNCTION
@code{true} is returned, else @code{false}. bfd_set_section_size
SYNOPSIS
boolean bfd_set_section_size(bfd *, asection *, bfd_size_type val);
DESCRIPTION
Sets @var{section} to the size @var{val}. If the operation is
ok, then <<true>> is returned, else <<false>>.
Possible error returns: Possible error returns:
@table @code o invalid_operation
@item invalid_operation
Writing has started to the BFD, so setting the size is invalid Writing has started to the BFD, so setting the size is invalid
@end table
*; PROTO(boolean, bfd_set_section_size,
(bfd *, asection *, bfd_size_type val));
*/ */
boolean boolean
@ -490,27 +569,35 @@ DEFUN(bfd_set_section_size,(abfd, ptr, val),
return true; return true;
} }
/*proto* bfd_set_section_contents /*
Sets the contents of the section @var{section} in BFD @var{abfd} to FUNCTION
the data starting in memory at @var{data}. The data is written to the bfd_set_section_contents
output section starting at offset @var{offset} for @var{count} bytes.
Normally @code{true} is returned, else @code{false}. Possible error SYNOPSIS
returns are: boolean bfd_set_section_contents
@table @code
@item no_contents
The output section does not have the @code{SEC_HAS_CONTENTS}
attribute, so nothing can be written to it.
@item and some more too
@end table
This routine is front end to the back end function @code{_bfd_set_section_contents}.
*; PROTO(boolean, bfd_set_section_contents,
(bfd *abfd, (bfd *abfd,
asection *section, asection *section,
PTR data, PTR data,
file_ptr offset, file_ptr offset,
bfd_size_type count)); bfd_size_type count);
DESCRIPTION
Sets the contents of the section @var{section} in BFD
@var{abfd} to the data starting in memory at @var{data}. The
data is written to the output section starting at offset
@var{offset} for @var{count} bytes.
Normally <<true>> is returned, else <<false>>. Possible error
returns are:
o no_contents
The output section does not have the <<SEC_HAS_CONTENTS>>
attribute, so nothing can be written to it.
o and some more too
This routine is front end to the back end function
<<_bfd_set_section_contents>>.
*/ */
@ -538,25 +625,26 @@ DEFUN(bfd_set_section_contents,(abfd, section, location, offset, count),
return false; return false;
} }
/*proto* bfd_get_section_contents /*
This function reads data from @var{section} in BFD @var{abfd} into FUNCTION
memory starting at @var{location}. The data is read at an offset of bfd_get_section_contents
@var{offset} from the start of the input section, and is read for
@var{count} bytes.
If the contents of a constuctor with the @code{SEC_CONSTUCTOR} flag SYNOPSIS
set are requested, then the @var{location} is filled with zeroes. boolean bfd_get_section_contents
If no errors occur, @code{true} is returned, else @code{false}.
Possible errors are:
@table @code
@item unknown yet
@end table
*; PROTO(boolean, bfd_get_section_contents,
(bfd *abfd, asection *section, PTR location, (bfd *abfd, asection *section, PTR location,
file_ptr offset, bfd_size_type count)); file_ptr offset, bfd_size_type count);
DESCRIPTION
This function reads data from @var{section} in BFD @var{abfd}
into memory starting at @var{location}. The data is read at an
offset of @var{offset} from the start of the input section,
and is read for @var{count} bytes.
If the contents of a constuctor with the <<SEC_CONSTUCTOR>>
flag set are requested, then the @var{location} is filled with
zeroes. If no errors occur, <<true>> is returned, else
<<false>>.
*/ */