diff options
Diffstat (limited to 'bfd/doc/section.texi')
| -rw-r--r-- | bfd/doc/section.texi | 1062 |
1 files changed, 1062 insertions, 0 deletions
diff --git a/bfd/doc/section.texi b/bfd/doc/section.texi new file mode 100644 index 0000000..8f856db --- /dev/null +++ b/bfd/doc/section.texi @@ -0,0 +1,1062 @@ +@section Sections +The raw data contained within a BFD is maintained through the +section abstraction. A single BFD may have any number of +sections. It keeps hold of them by pointing to the first; +each one points to the next in the list. + +Sections are supported in BFD in @code{section.c}. + +@menu +* Section Input:: +* Section Output:: +* typedef asection:: +* section prototypes:: +@end menu + +@node Section Input, Section Output, Sections, Sections +@subsection Section input +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, @code{a.out} would contain at least +three sections, called @code{.text}, @code{.data} and @code{.bss}. + +Names need not be unique; for example a COFF file may have several +sections named @code{.data}. + +Sometimes a BFD will contain more than the ``natural'' number of +sections. A back end may attach other sections containing +constructor data, or an application may add a section (using +@code{bfd_make_section}) to the sections attached to an already open +BFD. For example, the linker creates an extra section +@code{COMMON} for each input file's BFD to hold information about +common storage. + +The raw data is not necessarily read in when +the section descriptor is created. Some targets may leave the +data in place until a @code{bfd_get_section_contents} call is +made. Other back ends may read in all the data at once. For +example, an S-record file has to be read once to determine the +size of the data. An IEEE-695 file doesn't contain raw data in +sections, but data and relocation expressions intermixed, so +the data area has to be parsed to get out the data and +relocations. + +@node Section Output, typedef asection, Section Input, Sections +@subsection Section output +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}. + +Any program that creates or combines sections (e.g., the assembler +and linker) must use the @code{asection} fields @code{output_section} and +@code{output_offset} to indicate the file sections to which each +section must be written. (If the section is being created from +scratch, @code{output_section} should probably point to the section +itself and @code{output_offset} should probably be zero.) + +The data to be written comes from input sections attached +(via @code{output_section} pointers) 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. + +E.g., to create a section "O", starting at 0x100, 0x123 long, +containing two subsections, "A" at offset 0x0 (i.e., at vma +0x100) and "B" at offset 0x20 (i.e., at vma 0x120) the @code{asection} +structures would look like: + +@example + section name "A" + output_offset 0x00 + size 0x20 + output_section -----------> section name "O" + | vma 0x100 + section name "B" | size 0x123 + output_offset 0x20 | + size 0x103 | + output_section --------| +@end example + +@subsection Link orders +The data within a section is stored in a @dfn{link_order}. +These are much like the fixups in @code{gas}. The link_order +abstraction allows a section to grow and shrink within itself. + +A link_order knows how big it is, and which is the next +link_order and where the raw data for it is; it also points to +a list of relocations which apply to it. + +The link_order is used by the linker to perform relaxing on +final code. The compiler creates code which is as big as +necessary to make it work without relaxing, and the user can +select whether to relax. Sometimes relaxing takes a lot of +time. The linker runs around the relocations to see if any +are attached to data which can be shrunk, if so it does it on +a link_order by link_order basis. + + +@node typedef asection, section prototypes, Section Output, Sections +@subsection typedef asection +Here is the section structure: + + +@example + +typedef struct bfd_section +@{ + /* The name of the section; the name isn't a copy, the pointer is + the same as that passed to bfd_make_section. */ + const char *name; + + /* A unique sequence number. */ + int id; + + /* Which section in the bfd; 0..n-1 as sections are created in a bfd. */ + int index; + + /* The next section in the list belonging to the BFD, or NULL. */ + struct bfd_section *next; + + /* The previous section in the list belonging to the BFD, or NULL. */ + struct bfd_section *prev; + + /* The field flags contains attributes of the section. Some + flags are read in from the object file, and some are + synthesized from other information. */ + flagword flags; + +#define SEC_NO_FLAGS 0x000 + + /* Tells the OS to allocate space for this section when loading. + This is clear for a section containing debug information only. */ +#define SEC_ALLOC 0x001 + + /* Tells the OS to load the section from the file when loading. + This is clear for a .bss section. */ +#define SEC_LOAD 0x002 + + /* The section contains data still to be relocated, so there is + some relocation information too. */ +#define SEC_RELOC 0x004 + + /* A signal to the OS that the section contains read only data. */ +#define SEC_READONLY 0x008 + + /* The section contains code only. */ +#define SEC_CODE 0x010 + + /* The section contains data only. */ +#define SEC_DATA 0x020 + + /* The section will reside in ROM. */ +#define SEC_ROM 0x040 + + /* The section contains constructor information. This section + type is used by the linker to create lists of constructors and + destructors used by @code{g++}. When a back end sees a symbol + which should be used in a constructor list, it creates a new + section for the type of name (e.g., @code{__CTOR_LIST__}), attaches + the symbol to it, and builds a relocation. To build the lists + of constructors, all the linker has to do is catenate all the + sections called @code{__CTOR_LIST__} and relocate the data + contained within - exactly the operations it would peform on + standard data. */ +#define SEC_CONSTRUCTOR 0x080 + + /* The section has contents - a data section could be + @code{SEC_ALLOC} | @code{SEC_HAS_CONTENTS}; a debug section could be + @code{SEC_HAS_CONTENTS} */ +#define SEC_HAS_CONTENTS 0x100 + + /* An instruction to the linker to not output the section + even if it has information which would normally be written. */ +#define SEC_NEVER_LOAD 0x200 + + /* The section contains thread local data. */ +#define SEC_THREAD_LOCAL 0x400 + + /* The section has GOT references. This flag is only for the + linker, and is currently only used by the elf32-hppa back end. + It will be set if global offset table references were detected + in this section, which indicate to the linker that the section + contains PIC code, and must be handled specially when doing a + static link. */ +#define SEC_HAS_GOT_REF 0x800 + + /* The section contains common symbols (symbols may be defined + multiple times, the value of a symbol is the amount of + space it requires, and the largest symbol value is the one + used). Most targets have exactly one of these (which we + translate to bfd_com_section_ptr), but ECOFF has two. */ +#define SEC_IS_COMMON 0x1000 + + /* The section contains only debugging information. For + example, this is set for ELF .debug and .stab sections. + strip tests this flag to see if a section can be + discarded. */ +#define SEC_DEBUGGING 0x2000 + + /* The contents of this section are held in memory pointed to + by the contents field. This is checked by bfd_get_section_contents, + and the data is retrieved from memory if appropriate. */ +#define SEC_IN_MEMORY 0x4000 + + /* The contents of this section are to be excluded by the + linker for executable and shared objects unless those + objects are to be further relocated. */ +#define SEC_EXCLUDE 0x8000 + + /* The contents of this section are to be sorted based on the sum of + the symbol and addend values specified by the associated relocation + entries. Entries without associated relocation entries will be + appended to the end of the section in an unspecified order. */ +#define SEC_SORT_ENTRIES 0x10000 + + /* When linking, duplicate sections of the same name should be + discarded, rather than being combined into a single section as + is usually done. This is similar to how common symbols are + handled. See SEC_LINK_DUPLICATES below. */ +#define SEC_LINK_ONCE 0x20000 + + /* If SEC_LINK_ONCE is set, this bitfield describes how the linker + should handle duplicate sections. */ +#define SEC_LINK_DUPLICATES 0xc0000 + + /* This value for SEC_LINK_DUPLICATES means that duplicate + sections with the same name should simply be discarded. */ +#define SEC_LINK_DUPLICATES_DISCARD 0x0 + + /* This value for SEC_LINK_DUPLICATES means that the linker + should warn if there are any duplicate sections, although + it should still only link one copy. */ +#define SEC_LINK_DUPLICATES_ONE_ONLY 0x40000 + + /* This value for SEC_LINK_DUPLICATES means that the linker + should warn if any duplicate sections are a different size. */ +#define SEC_LINK_DUPLICATES_SAME_SIZE 0x80000 + + /* This value for SEC_LINK_DUPLICATES means that the linker + should warn if any duplicate sections contain different + contents. */ +#define SEC_LINK_DUPLICATES_SAME_CONTENTS \ + (SEC_LINK_DUPLICATES_ONE_ONLY | SEC_LINK_DUPLICATES_SAME_SIZE) + + /* This section was created by the linker as part of dynamic + relocation or other arcane processing. It is skipped when + going through the first-pass output, trusting that someone + else up the line will take care of it later. */ +#define SEC_LINKER_CREATED 0x100000 + + /* This section should not be subject to garbage collection. + Also set to inform the linker that this section should not be + listed in the link map as discarded. */ +#define SEC_KEEP 0x200000 + + /* This section contains "short" data, and should be placed + "near" the GP. */ +#define SEC_SMALL_DATA 0x400000 + + /* Attempt to merge identical entities in the section. + Entity size is given in the entsize field. */ +#define SEC_MERGE 0x800000 + + /* If given with SEC_MERGE, entities to merge are zero terminated + strings where entsize specifies character size instead of fixed + size entries. */ +#define SEC_STRINGS 0x1000000 + + /* This section contains data about section groups. */ +#define SEC_GROUP 0x2000000 + + /* The section is a COFF shared library section. This flag is + only for the linker. If this type of section appears in + the input file, the linker must copy it to the output file + without changing the vma or size. FIXME: Although this + was originally intended to be general, it really is COFF + specific (and the flag was renamed to indicate this). It + might be cleaner to have some more general mechanism to + allow the back end to control what the linker does with + sections. */ +#define SEC_COFF_SHARED_LIBRARY 0x4000000 + + /* This input section should be copied to output in reverse order + as an array of pointers. This is for ELF linker internal use + only. */ +#define SEC_ELF_REVERSE_COPY 0x4000000 + + /* This section contains data which may be shared with other + executables or shared objects. This is for COFF only. */ +#define SEC_COFF_SHARED 0x8000000 + + /* When a section with this flag is being linked, then if the size of + the input section is less than a page, it should not cross a page + boundary. If the size of the input section is one page or more, + it should be aligned on a page boundary. This is for TI + TMS320C54X only. */ +#define SEC_TIC54X_BLOCK 0x10000000 + + /* Conditionally link this section; do not link if there are no + references found to any symbol in the section. This is for TI + TMS320C54X only. */ +#define SEC_TIC54X_CLINK 0x20000000 + + /* Indicate that section has the no read flag set. This happens + when memory read flag isn't set. */ +#define SEC_COFF_NOREAD 0x40000000 + + /* End of section flags. */ + + /* Some internal packed boolean fields. */ + + /* See the vma field. */ + unsigned int user_set_vma : 1; + + /* A mark flag used by some of the linker backends. */ + unsigned int linker_mark : 1; + + /* Another mark flag used by some of the linker backends. Set for + output sections that have an input section. */ + unsigned int linker_has_input : 1; + + /* Mark flag used by some linker backends for garbage collection. */ + unsigned int gc_mark : 1; + + /* Section compression status. */ + unsigned int compress_status : 2; +#define COMPRESS_SECTION_NONE 0 +#define COMPRESS_SECTION_DONE 1 +#define DECOMPRESS_SECTION_SIZED 2 + + /* The following flags are used by the ELF linker. */ + + /* Mark sections which have been allocated to segments. */ + unsigned int segment_mark : 1; + + /* Type of sec_info information. */ + unsigned int sec_info_type:3; +#define SEC_INFO_TYPE_NONE 0 +#define SEC_INFO_TYPE_STABS 1 +#define SEC_INFO_TYPE_MERGE 2 +#define SEC_INFO_TYPE_EH_FRAME 3 +#define SEC_INFO_TYPE_JUST_SYMS 4 +#define SEC_INFO_TYPE_TARGET 5 + + /* Nonzero if this section uses RELA relocations, rather than REL. */ + unsigned int use_rela_p:1; + + /* Bits used by various backends. The generic code doesn't touch + these fields. */ + + unsigned int sec_flg0:1; + unsigned int sec_flg1:1; + unsigned int sec_flg2:1; + unsigned int sec_flg3:1; + unsigned int sec_flg4:1; + unsigned int sec_flg5:1; + + /* End of internal packed boolean fields. */ + + /* The virtual memory address of the section - where it will be + at run time. The symbols are relocated against this. The + user_set_vma flag is maintained by bfd; if it's not set, the + backend can assign addresses (for example, in @code{a.out}, where + the default address for @code{.data} is dependent on the specific + target and various flags). */ + bfd_vma vma; + + /* The load address of the section - where it would be in a + rom image; really only used for writing section header + information. */ + bfd_vma lma; + + /* The size of the section in octets, as it will be output. + Contains a value even if the section has no contents (e.g., the + size of @code{.bss}). */ + bfd_size_type size; + + /* For input sections, the original size on disk of the section, in + octets. This field should be set for any section whose size is + changed by linker relaxation. It is required for sections where + the linker relaxation scheme doesn't cache altered section and + reloc contents (stabs, eh_frame, SEC_MERGE, some coff relaxing + targets), and thus the original size needs to be kept to read the + section multiple times. For output sections, rawsize holds the + section size calculated on a previous linker relaxation pass. */ + bfd_size_type rawsize; + + /* The compressed size of the section in octets. */ + bfd_size_type compressed_size; + + /* Relaxation table. */ + struct relax_table *relax; + + /* Count of used relaxation table entries. */ + int relax_count; + + + /* If this section is going to be output, then this value is the + offset in *bytes* into the output section of the first byte in the + input section (byte ==> smallest addressable unit on the + target). In most cases, if this was going to start at the + 100th octet (8-bit quantity) in the output section, this value + would be 100. However, if the target byte size is 16 bits + (bfd_octets_per_byte is "2"), this value would be 50. */ + bfd_vma output_offset; + + /* The output section through which to map on output. */ + struct bfd_section *output_section; + + /* The alignment requirement of the section, as an exponent of 2 - + e.g., 3 aligns to 2^3 (or 8). */ + unsigned int alignment_power; + + /* If an input section, a pointer to a vector of relocation + records for the data in this section. */ + struct reloc_cache_entry *relocation; + + /* If an output section, a pointer to a vector of pointers to + relocation records for the data in this section. */ + struct reloc_cache_entry **orelocation; + + /* The number of relocation records in one of the above. */ + unsigned reloc_count; + + /* Information below is back end specific - and not always used + or updated. */ + + /* File position of section data. */ + file_ptr filepos; + + /* File position of relocation info. */ + file_ptr rel_filepos; + + /* File position of line data. */ + file_ptr line_filepos; + + /* Pointer to data for applications. */ + void *userdata; + + /* If the SEC_IN_MEMORY flag is set, this points to the actual + contents. */ + unsigned char *contents; + + /* Attached line number information. */ + alent *lineno; + + /* Number of line number records. */ + unsigned int lineno_count; + + /* Entity size for merging purposes. */ + unsigned int entsize; + + /* Points to the kept section if this section is a link-once section, + and is discarded. */ + struct bfd_section *kept_section; + + /* When a section is being output, this value changes as more + linenumbers are written out. */ + file_ptr moving_line_filepos; + + /* What the section number is in the target world. */ + int target_index; + + void *used_by_bfd; + + /* If this is a constructor section then here is a list of the + relocations created to relocate items within it. */ + struct relent_chain *constructor_chain; + + /* The BFD which owns the section. */ + bfd *owner; + + /* A symbol which points at this section only. */ + struct bfd_symbol *symbol; + struct bfd_symbol **symbol_ptr_ptr; + + /* Early in the link process, map_head and map_tail are used to build + a list of input sections attached to an output section. Later, + output sections use these fields for a list of bfd_link_order + structs. */ + union @{ + struct bfd_link_order *link_order; + struct bfd_section *s; + @} map_head, map_tail; +@} asection; + +/* Relax table contains information about instructions which can + be removed by relaxation -- replacing a long address with a + short address. */ +struct relax_table @{ + /* Address where bytes may be deleted. */ + bfd_vma addr; + + /* Number of bytes to be deleted. */ + int size; +@}; + +/* Note: the following are provided as inline functions rather than macros + because not all callers use the return value. A macro implementation + would use a comma expression, eg: "((ptr)->foo = val, TRUE)" and some + compilers will complain about comma expressions that have no effect. */ +static inline bfd_boolean +bfd_set_section_userdata (bfd * abfd ATTRIBUTE_UNUSED, asection * ptr, void * val) +@{ + ptr->userdata = val; + return TRUE; +@} + +static inline bfd_boolean +bfd_set_section_vma (bfd * abfd ATTRIBUTE_UNUSED, asection * ptr, bfd_vma val) +@{ + ptr->vma = ptr->lma = val; + ptr->user_set_vma = TRUE; + return TRUE; +@} + +static inline bfd_boolean +bfd_set_section_alignment (bfd * abfd ATTRIBUTE_UNUSED, asection * ptr, unsigned int val) +@{ + ptr->alignment_power = val; + return TRUE; +@} + +/* These sections are global, and are managed by BFD. The application + and target back end are not permitted to change the values in + these sections. */ +extern asection _bfd_std_section[4]; + +#define BFD_ABS_SECTION_NAME "*ABS*" +#define BFD_UND_SECTION_NAME "*UND*" +#define BFD_COM_SECTION_NAME "*COM*" +#define BFD_IND_SECTION_NAME "*IND*" + +/* Pointer to the common section. */ +#define bfd_com_section_ptr (&_bfd_std_section[0]) +/* Pointer to the undefined section. */ +#define bfd_und_section_ptr (&_bfd_std_section[1]) +/* Pointer to the absolute section. */ +#define bfd_abs_section_ptr (&_bfd_std_section[2]) +/* Pointer to the indirect section. */ +#define bfd_ind_section_ptr (&_bfd_std_section[3]) + +#define bfd_is_und_section(sec) ((sec) == bfd_und_section_ptr) +#define bfd_is_abs_section(sec) ((sec) == bfd_abs_section_ptr) +#define bfd_is_ind_section(sec) ((sec) == bfd_ind_section_ptr) + +#define bfd_is_const_section(SEC) \ + ( ((SEC) == bfd_abs_section_ptr) \ + || ((SEC) == bfd_und_section_ptr) \ + || ((SEC) == bfd_com_section_ptr) \ + || ((SEC) == bfd_ind_section_ptr)) + +/* Macros to handle insertion and deletion of a bfd's sections. These + only handle the list pointers, ie. do not adjust section_count, + target_index etc. */ +#define bfd_section_list_remove(ABFD, S) \ + do \ + @{ \ + asection *_s = S; \ + asection *_next = _s->next; \ + asection *_prev = _s->prev; \ + if (_prev) \ + _prev->next = _next; \ + else \ + (ABFD)->sections = _next; \ + if (_next) \ + _next->prev = _prev; \ + else \ + (ABFD)->section_last = _prev; \ + @} \ + while (0) +#define bfd_section_list_append(ABFD, S) \ + do \ + @{ \ + asection *_s = S; \ + bfd *_abfd = ABFD; \ + _s->next = NULL; \ + if (_abfd->section_last) \ + @{ \ + _s->prev = _abfd->section_last; \ + _abfd->section_last->next = _s; \ + @} \ + else \ + @{ \ + _s->prev = NULL; \ + _abfd->sections = _s; \ + @} \ + _abfd->section_last = _s; \ + @} \ + while (0) +#define bfd_section_list_prepend(ABFD, S) \ + do \ + @{ \ + asection *_s = S; \ + bfd *_abfd = ABFD; \ + _s->prev = NULL; \ + if (_abfd->sections) \ + @{ \ + _s->next = _abfd->sections; \ + _abfd->sections->prev = _s; \ + @} \ + else \ + @{ \ + _s->next = NULL; \ + _abfd->section_last = _s; \ + @} \ + _abfd->sections = _s; \ + @} \ + while (0) +#define bfd_section_list_insert_after(ABFD, A, S) \ + do \ + @{ \ + asection *_a = A; \ + asection *_s = S; \ + asection *_next = _a->next; \ + _s->next = _next; \ + _s->prev = _a; \ + _a->next = _s; \ + if (_next) \ + _next->prev = _s; \ + else \ + (ABFD)->section_last = _s; \ + @} \ + while (0) +#define bfd_section_list_insert_before(ABFD, B, S) \ + do \ + @{ \ + asection *_b = B; \ + asection *_s = S; \ + asection *_prev = _b->prev; \ + _s->prev = _prev; \ + _s->next = _b; \ + _b->prev = _s; \ + if (_prev) \ + _prev->next = _s; \ + else \ + (ABFD)->sections = _s; \ + @} \ + while (0) +#define bfd_section_removed_from_list(ABFD, S) \ + ((S)->next == NULL ? (ABFD)->section_last != (S) : (S)->next->prev != (S)) + +#define BFD_FAKE_SECTION(SEC, FLAGS, SYM, NAME, IDX) \ + /* name, id, index, next, prev, flags, user_set_vma, */ \ + @{ NAME, IDX, 0, NULL, NULL, FLAGS, 0, \ + \ + /* linker_mark, linker_has_input, gc_mark, decompress_status, */ \ + 0, 0, 1, 0, \ + \ + /* segment_mark, sec_info_type, use_rela_p, */ \ + 0, 0, 0, \ + \ + /* sec_flg0, sec_flg1, sec_flg2, sec_flg3, sec_flg4, sec_flg5, */ \ + 0, 0, 0, 0, 0, 0, \ + \ + /* vma, lma, size, rawsize, compressed_size, relax, relax_count, */ \ + 0, 0, 0, 0, 0, 0, 0, \ + \ + /* output_offset, output_section, alignment_power, */ \ + 0, &SEC, 0, \ + \ + /* relocation, orelocation, reloc_count, filepos, rel_filepos, */ \ + NULL, NULL, 0, 0, 0, \ + \ + /* line_filepos, userdata, contents, lineno, lineno_count, */ \ + 0, NULL, NULL, NULL, 0, \ + \ + /* entsize, kept_section, moving_line_filepos, */ \ + 0, NULL, 0, \ + \ + /* target_index, used_by_bfd, constructor_chain, owner, */ \ + 0, NULL, NULL, NULL, \ + \ + /* symbol, symbol_ptr_ptr, */ \ + (struct bfd_symbol *) SYM, &SEC.symbol, \ + \ + /* map_head, map_tail */ \ + @{ NULL @}, @{ NULL @} \ + @} + +@end example + +@node section prototypes, , typedef asection, Sections +@subsection Section prototypes +These are the functions exported by the section handling part of BFD. + +@findex bfd_section_list_clear +@subsubsection @code{bfd_section_list_clear} +@strong{Synopsis} +@example +void bfd_section_list_clear (bfd *); +@end example +@strong{Description}@* +Clears the section list, and also resets the section count and +hash table entries. + +@findex bfd_get_section_by_name +@subsubsection @code{bfd_get_section_by_name} +@strong{Synopsis} +@example +asection *bfd_get_section_by_name (bfd *abfd, const char *name); +@end example +@strong{Description}@* +Return the most recently created section attached to @var{abfd} +named @var{name}. Return NULL if no such section exists. + +@findex bfd_get_next_section_by_name +@subsubsection @code{bfd_get_next_section_by_name} +@strong{Synopsis} +@example +asection *bfd_get_next_section_by_name (asection *sec); +@end example +@strong{Description}@* +Given @var{sec} is a section returned by @code{bfd_get_section_by_name}, +return the next most recently created section attached to the same +BFD with the same name. Return NULL if no such section exists. + +@findex bfd_get_linker_section +@subsubsection @code{bfd_get_linker_section} +@strong{Synopsis} +@example +asection *bfd_get_linker_section (bfd *abfd, const char *name); +@end example +@strong{Description}@* +Return the linker created section attached to @var{abfd} +named @var{name}. Return NULL if no such section exists. + +@findex bfd_get_section_by_name_if +@subsubsection @code{bfd_get_section_by_name_if} +@strong{Synopsis} +@example +asection *bfd_get_section_by_name_if + (bfd *abfd, + const char *name, + bfd_boolean (*func) (bfd *abfd, asection *sect, void *obj), + void *obj); +@end example +@strong{Description}@* +Call the provided function @var{func} for each section +attached to the BFD @var{abfd} whose name matches @var{name}, +passing @var{obj} as an argument. The function will be called +as if by + +@example + func (abfd, the_section, obj); +@end example + +It returns the first section for which @var{func} returns true, +otherwise @code{NULL}. + +@findex bfd_get_unique_section_name +@subsubsection @code{bfd_get_unique_section_name} +@strong{Synopsis} +@example +char *bfd_get_unique_section_name + (bfd *abfd, const char *templat, int *count); +@end example +@strong{Description}@* +Invent a section name that is unique in @var{abfd} by tacking +a dot and a digit suffix onto the original @var{templat}. If +@var{count} is non-NULL, then it specifies the first number +tried as a suffix to generate a unique name. The value +pointed to by @var{count} will be incremented in this case. + +@findex bfd_make_section_old_way +@subsubsection @code{bfd_make_section_old_way} +@strong{Synopsis} +@example +asection *bfd_make_section_old_way (bfd *abfd, const char *name); +@end example +@strong{Description}@* +Create a new empty section called @var{name} +and attach it to the end of the chain of sections for the +BFD @var{abfd}. 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 it was rewritten.... + +Possible errors are: +@itemize @bullet + +@item +@code{bfd_error_invalid_operation} - +If output has already started for this BFD. +@item +@code{bfd_error_no_memory} - +If memory allocation fails. +@end itemize + +@findex bfd_make_section_anyway_with_flags +@subsubsection @code{bfd_make_section_anyway_with_flags} +@strong{Synopsis} +@example +asection *bfd_make_section_anyway_with_flags + (bfd *abfd, const char *name, flagword flags); +@end example +@strong{Description}@* +Create a new empty section called @var{name} and attach it to the end of +the chain of sections for @var{abfd}. Create a new section even if there +is already a section with that name. Also set the attributes of the +new section to the value @var{flags}. + +Return @code{NULL} and set @code{bfd_error} on error; possible errors are: +@itemize @bullet + +@item +@code{bfd_error_invalid_operation} - If output has already started for @var{abfd}. +@item +@code{bfd_error_no_memory} - If memory allocation fails. +@end itemize + +@findex bfd_make_section_anyway +@subsubsection @code{bfd_make_section_anyway} +@strong{Synopsis} +@example +asection *bfd_make_section_anyway (bfd *abfd, const char *name); +@end example +@strong{Description}@* +Create a new empty section called @var{name} and attach it to the end of +the chain of sections for @var{abfd}. Create a new section even if there +is already a section with that name. + +Return @code{NULL} and set @code{bfd_error} on error; possible errors are: +@itemize @bullet + +@item +@code{bfd_error_invalid_operation} - If output has already started for @var{abfd}. +@item +@code{bfd_error_no_memory} - If memory allocation fails. +@end itemize + +@findex bfd_make_section_with_flags +@subsubsection @code{bfd_make_section_with_flags} +@strong{Synopsis} +@example +asection *bfd_make_section_with_flags + (bfd *, const char *name, flagword flags); +@end example +@strong{Description}@* +Like @code{bfd_make_section_anyway}, but return @code{NULL} (without calling +bfd_set_error ()) without changing the section chain if there is already a +section named @var{name}. Also set the attributes of the new section to +the value @var{flags}. If there is an error, return @code{NULL} and set +@code{bfd_error}. + +@findex bfd_make_section +@subsubsection @code{bfd_make_section} +@strong{Synopsis} +@example +asection *bfd_make_section (bfd *, const char *name); +@end example +@strong{Description}@* +Like @code{bfd_make_section_anyway}, but return @code{NULL} (without calling +bfd_set_error ()) without changing the section chain if there is already a +section named @var{name}. If there is an error, return @code{NULL} and set +@code{bfd_error}. + +@findex bfd_set_section_flags +@subsubsection @code{bfd_set_section_flags} +@strong{Synopsis} +@example +bfd_boolean bfd_set_section_flags + (bfd *abfd, asection *sec, flagword flags); +@end example +@strong{Description}@* +Set the attributes of the section @var{sec} in the BFD +@var{abfd} to the value @var{flags}. Return @code{TRUE} on success, +@code{FALSE} on error. Possible error returns are: + +@itemize @bullet + +@item +@code{bfd_error_invalid_operation} - +The section cannot have one or more of the attributes +requested. For example, a .bss section in @code{a.out} may not +have the @code{SEC_HAS_CONTENTS} field set. +@end itemize + +@findex bfd_rename_section +@subsubsection @code{bfd_rename_section} +@strong{Synopsis} +@example +void bfd_rename_section + (bfd *abfd, asection *sec, const char *newname); +@end example +@strong{Description}@* +Rename section @var{sec} in @var{abfd} to @var{newname}. + +@findex bfd_map_over_sections +@subsubsection @code{bfd_map_over_sections} +@strong{Synopsis} +@example +void bfd_map_over_sections + (bfd *abfd, + void (*func) (bfd *abfd, asection *sect, void *obj), + void *obj); +@end example +@strong{Description}@* +Call 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 + +@example + func (abfd, the_section, obj); +@end example + +This is the preferred method for iterating over sections; an +alternative would be to use a loop: + +@example + asection *p; + for (p = abfd->sections; p != NULL; p = p->next) + func (abfd, p, ...) +@end example + +@findex bfd_sections_find_if +@subsubsection @code{bfd_sections_find_if} +@strong{Synopsis} +@example +asection *bfd_sections_find_if + (bfd *abfd, + bfd_boolean (*operation) (bfd *abfd, asection *sect, void *obj), + void *obj); +@end example +@strong{Description}@* +Call the provided function @var{operation} for each section +attached to the BFD @var{abfd}, passing @var{obj} as an +argument. The function will be called as if by + +@example + operation (abfd, the_section, obj); +@end example + +It returns the first section for which @var{operation} returns true. + +@findex bfd_set_section_size +@subsubsection @code{bfd_set_section_size} +@strong{Synopsis} +@example +bfd_boolean bfd_set_section_size + (bfd *abfd, asection *sec, bfd_size_type val); +@end example +@strong{Description}@* +Set @var{sec} to the size @var{val}. If the operation is +ok, then @code{TRUE} is returned, else @code{FALSE}. + +Possible error returns: +@itemize @bullet + +@item +@code{bfd_error_invalid_operation} - +Writing has started to the BFD, so setting the size is invalid. +@end itemize + +@findex bfd_set_section_contents +@subsubsection @code{bfd_set_section_contents} +@strong{Synopsis} +@example +bfd_boolean bfd_set_section_contents + (bfd *abfd, asection *section, const void *data, + file_ptr offset, bfd_size_type count); +@end example +@strong{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} octets. + +Normally @code{TRUE} is returned, else @code{FALSE}. Possible error +returns are: +@itemize @bullet + +@item +@code{bfd_error_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 itemize +This routine is front end to the back end function +@code{_bfd_set_section_contents}. + +@findex bfd_get_section_contents +@subsubsection @code{bfd_get_section_contents} +@strong{Synopsis} +@example +bfd_boolean bfd_get_section_contents + (bfd *abfd, asection *section, void *location, file_ptr offset, + bfd_size_type count); +@end example +@strong{Description}@* +Read 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 constructor with the @code{SEC_CONSTRUCTOR} +flag set are requested or if the section does not have the +@code{SEC_HAS_CONTENTS} flag set, then the @var{location} is filled +with zeroes. If no errors occur, @code{TRUE} is returned, else +@code{FALSE}. + +@findex bfd_malloc_and_get_section +@subsubsection @code{bfd_malloc_and_get_section} +@strong{Synopsis} +@example +bfd_boolean bfd_malloc_and_get_section + (bfd *abfd, asection *section, bfd_byte **buf); +@end example +@strong{Description}@* +Read all data from @var{section} in BFD @var{abfd} +into a buffer, *@var{buf}, malloc'd by this function. + +@findex bfd_copy_private_section_data +@subsubsection @code{bfd_copy_private_section_data} +@strong{Synopsis} +@example +bfd_boolean bfd_copy_private_section_data + (bfd *ibfd, asection *isec, bfd *obfd, asection *osec); +@end example +@strong{Description}@* +Copy private section information from @var{isec} in the BFD +@var{ibfd} to the section @var{osec} in the BFD @var{obfd}. +Return @code{TRUE} on success, @code{FALSE} on error. Possible error +returns are: + +@itemize @bullet + +@item +@code{bfd_error_no_memory} - +Not enough memory exists to create private data for @var{osec}. +@end itemize +@example +#define bfd_copy_private_section_data(ibfd, isection, obfd, osection) \ + BFD_SEND (obfd, _bfd_copy_private_section_data, \ + (ibfd, isection, obfd, osection)) +@end example + +@findex bfd_generic_is_group_section +@subsubsection @code{bfd_generic_is_group_section} +@strong{Synopsis} +@example +bfd_boolean bfd_generic_is_group_section (bfd *, const asection *sec); +@end example +@strong{Description}@* +Returns TRUE if @var{sec} is a member of a group. + +@findex bfd_generic_discard_group +@subsubsection @code{bfd_generic_discard_group} +@strong{Synopsis} +@example +bfd_boolean bfd_generic_discard_group (bfd *abfd, asection *group); +@end example +@strong{Description}@* +Remove all members of @var{group} from the output. + |