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GNU Info File | 1994-12-17 | 45.9 KB | 1,063 lines

This is Info file ld.info, produced by Makeinfo-1.55 from the input file ./ld.texinfo. START-INFO-DIR-ENTRY * Ld: (ld). The GNU linker. END-INFO-DIR-ENTRY This file documents the GNU linker LD. Copyright (C) 1991, 1992, 1993, 1994 Free Software Foundation, Inc. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions. File: ld.info, Node: Section Data Expressions, Next: Section Options, Prev: Section Placement, Up: SECTIONS Section Data Expressions ------------------------ The foregoing statements arrange, in your output file, data originating from your input files. You can also place data directly in an output section from the link command script. Most of these additional statements involve expressions; *note Expressions::.. Although these statements are shown separately here for ease of presentation, no such segregation is needed within a section definition in the `SECTIONS' command; you can intermix them freely with any of the statements we've just described. `CREATE_OBJECT_SYMBOLS' Create a symbol for each input file in the current section, set to the address of the first byte of data written from that input file. For instance, with `a.out' files it is conventional to have a symbol for each input file. You can accomplish this by defining the output `.text' section as follows: SECTIONS { .text 0x2020 : { CREATE_OBJECT_SYMBOLS *(.text) _etext = ALIGN(0x2000); } ... } If `sample.ld' is a file containing this script, and `a.o', `b.o', `c.o', and `d.o' are four input files with contents like the following-- /* a.c */ afunction() { } int adata=1; int abss; `ld -M -T sample.ld a.o b.o c.o d.o' would create a map like this, containing symbols matching the object file names: 00000000 A __DYNAMIC 00004020 B _abss 00004000 D _adata 00002020 T _afunction 00004024 B _bbss 00004008 D _bdata 00002038 T _bfunction 00004028 B _cbss 00004010 D _cdata 00002050 T _cfunction 0000402c B _dbss 00004018 D _ddata 00002068 T _dfunction 00004020 D _edata 00004030 B _end 00004000 T _etext 00002020 t a.o 00002038 t b.o 00002050 t c.o 00002068 t d.o `SYMBOL = EXPRESSION ;' `SYMBOL F= EXPRESSION ;' SYMBOL is any symbol name (*note Symbols::.). "F=" refers to any of the operators `&= += -= *= /=' which combine arithmetic and assignment. When you assign a value to a symbol within a particular section definition, the value is relative to the beginning of the section (*note Assignment::.). If you write SECTIONS { abs = 14 ; ... .data : { ... rel = 14 ; ... } abs2 = 14 + ADDR(.data); ... } `abs' and `rel' do not have the same value; `rel' has the same value as `abs2'. `BYTE(EXPRESSION)' `SHORT(EXPRESSION)' `LONG(EXPRESSION)' `QUAD(EXPRESSION)' By including one of these four statements in a section definition, you can explicitly place one, two, four, or eight bytes (respectively) at the current address of that section. `QUAD' is only supported when using a 64 bit host or target. Multiple-byte quantities are represented in whatever byte order is appropriate for the output file format (*note BFD::.). `FILL(EXPRESSION)' Specify the "fill pattern" for the current section. Any otherwise unspecified regions of memory within the section (for example, regions you skip over by assigning a new value to the location counter `.') are filled with the two least significant bytes from the EXPRESSION argument. A `FILL' statement covers memory locations *after* the point it occurs in the section definition; by including more than one `FILL' statement, you can have different fill patterns in different parts of an output section. File: ld.info, Node: Section Options, Prev: Section Data Expressions, Up: SECTIONS Optional Section Attributes --------------------------- Here is the full syntax of a section definition, including all the optional portions: SECTIONS { ... SECNAME START BLOCK(ALIGN) (NOLOAD) : AT ( LDADR ) { CONTENTS } >REGION =FILL ... } SECNAME and CONTENTS are required. *Note Section Definition::, and *note Section Placement::. for details on CONTENTS. The remaining elements--START, `BLOCK(ALIGN)', `(NOLOAD)', `AT ( LDADR )', `>REGION', and `=FILL'--are all optional. `START' You can force the output section to be loaded at a specified address by specifying START immediately following the section name. sTART can be represented as any expression. The following example generates section OUTPUT at location `0x40000000': SECTIONS { ... output 0x40000000: { ... } ... } `BLOCK(ALIGN)' You can include `BLOCK()' specification to advance the location counter `.' prior to the beginning of the section, so that the section will begin at the specified alignment. ALIGN is an expression. `(NOLOAD)' Use `(NOLOAD)' to prevent a section from being loaded into memory each time it is accessed. For example, in the script sample below, the `ROM' segment is addressed at memory location `0' and does not need to be loaded into each object file: SECTIONS { ROM 0 (NOLOAD) : { ... } ... } `AT ( LDADR )' The expression LDADR that follows the `AT' keyword specifies the load address of the section. The default (if you do not use the `AT' keyword) is to make the load address the same as the relocation address. This feature is designed to make it easy to build a ROM image. For example, this `SECTIONS' definition creates two output sections: one called `.text', which starts at `0x1000', and one called `.mdata', which is loaded at the end of the `.text' section even though its relocation address is `0x2000'. The symbol `_data' is defined with the value `0x2000': SECTIONS { .text 0x1000 : { *(.text) _etext = . ; } .mdata 0x2000 : AT ( ADDR(.text) + SIZEOF ( .text ) ) { _data = . ; *(.data); _edata = . ; } .bss 0x3000 : { _bstart = . ; *(.bss) *(COMMON) ; _bend = . ;} } The run-time initialization code (for C programs, usually `crt0') for use with a ROM generated this way has to include something like the following, to copy the initialized data from the ROM image to its runtime address: char *src = _etext; char *dst = _data; /* ROM has data at end of text; copy it. */ while (dst < _edata) { *dst++ = *src++; } /* Zero bss */ for (dst = _bstart; dst< _bend; dst++) *dst = 0; `>REGION' Assign this section to a previously defined region of memory. *Note MEMORY::. `=FILL' Including `=FILL' in a section definition specifies the initial fill value for that section. You may use any expression to specify FILL. Any unallocated holes in the current output section when written to the output file will be filled with the two least significant bytes of the value, repeated as necessary. You can also change the fill value with a `FILL' statement in the CONTENTS of a section definition. File: ld.info, Node: Entry Point, Next: Option Commands, Prev: SECTIONS, Up: Commands The Entry Point =============== The linker command language includes a command specifically for defining the first executable instruction in an output file (its "entry point"). Its argument is a symbol name: ENTRY(SYMBOL) Like symbol assignments, the `ENTRY' command may be placed either as an independent command in the command file, or among the section definitions within the `SECTIONS' command--whatever makes the most sense for your layout. `ENTRY' is only one of several ways of choosing the entry point. You may indicate it in any of the following ways (shown in descending order of priority: methods higher in the list override methods lower down). * the `-e' ENTRY command-line option; * the `ENTRY(SYMBOL)' command in a linker control script; * the value of the symbol `start', if present; * the value of the symbol `_main', if present; * the address of the first byte of the `.text' section, if present; * The address `0'. For example, you can use these rules to generate an entry point with an assignment statement: if no symbol `start' is defined within your input files, you can simply define it, assigning it an appropriate value-- start = 0x2020; The example shows an absolute address, but you can use any expression. For example, if your input object files use some other symbol-name convention for the entry point, you can just assign the value of whatever symbol contains the start address to `start': start = other_symbol ; File: ld.info, Node: Option Commands, Prev: Entry Point, Up: Commands Option Commands =============== The command language includes a number of other commands that you can use for specialized purposes. They are similar in purpose to command-line options. `CONSTRUCTORS' This command ties up C++ style constructor and destructor records. The details of the constructor representation vary from one object format to another, but usually lists of constructors and destructors appear as special sections. The `CONSTRUCTORS' command specifies where the linker is to place the data from these sections, relative to the rest of the linked output. Constructor data is marked by the symbol `__CTOR_LIST__' at the start, and `__CTOR_LIST_END' at the end; destructor data is bracketed similarly, between `__DTOR_LIST__' and `__DTOR_LIST_END'. (The compiler must arrange to actually run this code; GNU C++ calls constructors from a subroutine `__main', which it inserts automatically into the startup code for `main', and destructors from `_exit'.) `FLOAT' `NOFLOAT' These keywords were used in some older linkers to request a particular math subroutine library. `ld' doesn't use the keywords, assuming instead that any necessary subroutines are in libraries specified using the general mechanisms for linking to archives; but to permit the use of scripts that were written for the older linkers, the keywords `FLOAT' and `NOFLOAT' are accepted and ignored. `FORCE_COMMON_ALLOCATION' This command has the same effect as the `-d' command-line option: to make `ld' assign space to common symbols even if a relocatable output file is specified (`-r'). `INPUT ( FILE, FILE, ... )' `INPUT ( FILE FILE ... )' Use this command to include binary input files in the link, without including them in a particular section definition. Specify the full name for each FILE, including `.a' if required. `ld' searches for each FILE through the archive-library search path, just as for files you specify on the command line. See the description of `-L' in *Note Command Line Options: Options. `GROUP ( FILE, FILE, ... )' `GROUP ( FILE FILE ... )' This command is like `INPUT', except that the named files should all be archives, and they are searched repeatedly until no new undefined references are created. See the description of `-(' in *Note Command Line Options: Options. `OUTPUT ( FILENAME )' Use this command to name the link output file FILENAME. The effect of `OUTPUT(FILENAME)' is identical to the effect of `-o FILENAME', which overrides it. You can use this command to supply a default output-file name other than `a.out'. `OUTPUT_ARCH ( BFDNAME )' Specify a particular output machine architecture, with one of the names used by the BFD back-end routines (*note BFD::.). This command is often unnecessary; the architecture is most often set implicitly by either the system BFD configuration or as a side effect of the `OUTPUT_FORMAT' command. `OUTPUT_FORMAT ( BFDNAME )' When `ld' is configured to support multiple object code formats, you can use this command to specify a particular output format. bFDNAME is one of the names used by the BFD back-end routines (*note BFD::.). The effect is identical to the effect of the `-oformat' command-line option. This selection affects only the output file; the related command `TARGET' affects primarily input files. `SEARCH_DIR ( PATH )' Add PATH to the list of paths where `ld' looks for archive libraries. `SEARCH_DIR(PATH)' has the same effect as `-LPATH' on the command line. `STARTUP ( FILENAME )' Ensure that FILENAME is the first input file used in the link process. `TARGET ( FORMAT )' When `ld' is configured to support multiple object code formats, you can use this command to change the input-file object code format (like the command-line option `-b' or its synonym `-format'). The argument FORMAT is one of the strings used by BFD to name binary formats. If `TARGET' is specified but `OUTPUT_FORMAT' is not, the last `TARGET' argument is also used as the default format for the `ld' output file. *Note BFD::. If you don't use the `TARGET' command, `ld' uses the value of the environment variable `GNUTARGET', if available, to select the output file format. If that variable is also absent, `ld' uses the default format configured for your machine in the BFD libraries. File: ld.info, Node: Machine Dependent, Next: BFD, Prev: Commands, Up: Top Machine Dependent Features ************************** `ld' has additional features on some platforms; the following sections describe them. Machines where `ld' has no additional functionality are not listed. * Menu: * H8/300:: `ld' and the H8/300 * i960:: `ld' and the Intel 960 family File: ld.info, Node: H8/300, Next: i960, Up: Machine Dependent `ld' and the H8/300 =================== For the H8/300, `ld' can perform these global optimizations when you specify the `-relax' command-line option. *relaxing address modes* `ld' finds all `jsr' and `jmp' instructions whose targets are within eight bits, and turns them into eight-bit program-counter relative `bsr' and `bra' instructions, respectively. *synthesizing instructions* `ld' finds all `mov.b' instructions which use the sixteen-bit absolute address form, but refer to the top page of memory, and changes them to use the eight-bit address form. (That is: the linker turns `mov.b `@'AA:16' into `mov.b `@'AA:8' whenever the address AA is in the top page of memory). File: ld.info, Node: i960, Prev: H8/300, Up: Machine Dependent `ld' and the Intel 960 family ============================= You can use the `-AARCHITECTURE' command line option to specify one of the two-letter names identifying members of the 960 family; the option specifies the desired output target, and warns of any incompatible instructions in the input files. It also modifies the linker's search strategy for archive libraries, to support the use of libraries specific to each particular architecture, by including in the search loop names suffixed with the string identifying the architecture. For example, if your `ld' command line included `-ACA' as well as `-ltry', the linker would look (in its built-in search paths, and in any paths you specify with `-L') for a library with the names try libtry.a tryca libtryca.a The first two possibilities would be considered in any event; the last two are due to the use of `-ACA'. You can meaningfully use `-A' more than once on a command line, since the 960 architecture family allows combination of target architectures; each use will add another pair of name variants to search for when `-l' specifies a library. `ld' supports the `-relax' option for the i960 family. If you specify `-relax', `ld' finds all `balx' and `calx' instructions whose targets are within 24 bits, and turns them into 24-bit program-counter relative `bal' and `cal' instructions, respectively. `ld' also turns `cal' instructions into `bal' instructions when it determines that the target subroutine is a leaf routine (that is, the target subroutine does not itself call any subroutines). File: ld.info, Node: BFD, Next: MRI, Prev: Machine Dependent, Up: Top BFD *** The linker accesses object and archive files using the BFD libraries. These libraries allow the linker to use the same routines to operate on object files whatever the object file format. A different object file format can be supported simply by creating a new BFD back end and adding it to the library. To conserve runtime memory, however, the linker and associated tools are usually configured to support only a subset of the object file formats available. You can use `objdump -i' (*note objdump: (binutils.info)objdump.) to list all the formats available for your configuration. As with most implementations, BFD is a compromise between several conflicting requirements. The major factor influencing BFD design was efficiency: any time used converting between formats is time which would not have been spent had BFD not been involved. This is partly offset by abstraction payback; since BFD simplifies applications and back ends, more time and care may be spent optimizing algorithms for a greater speed. One minor artifact of the BFD solution which you should bear in mind is the potential for information loss. There are two places where useful information can be lost using the BFD mechanism: during conversion and during output. *Note BFD information loss::. * Menu: * BFD outline:: How it works: an outline of BFD File: ld.info, Node: BFD outline, Up: BFD How it works: an outline of BFD =============================== When an object file is opened, BFD subroutines automatically determine the format of the input object file. They then build a descriptor in memory with pointers to routines that will be used to access elements of the object file's data structures. As different information from the the object files is required, BFD reads from different sections of the file and processes them. For example, a very common operation for the linker is processing symbol tables. Each BFD back end provides a routine for converting between the object file's representation of symbols and an internal canonical format. When the linker asks for the symbol table of an object file, it calls through a memory pointer to the routine from the relevant BFD back end which reads and converts the table into a canonical form. The linker then operates upon the canonical form. When the link is finished and the linker writes the output file's symbol table, another BFD back end routine is called to take the newly created symbol table and convert it into the chosen output format. * Menu: * BFD information loss:: Information Loss * Canonical format:: The BFD canonical object-file format File: ld.info, Node: BFD information loss, Next: Canonical format, Up: BFD outline Information Loss ---------------- *Information can be lost during output.* The output formats supported by BFD do not provide identical facilities, and information which can be described in one form has nowhere to go in another format. One example of this is alignment information in `b.out'. There is nowhere in an `a.out' format file to store alignment information on the contained data, so when a file is linked from `b.out' and an `a.out' image is produced, alignment information will not propagate to the output file. (The linker will still use the alignment information internally, so the link is performed correctly). Another example is COFF section names. COFF files may contain an unlimited number of sections, each one with a textual section name. If the target of the link is a format which does not have many sections (e.g., `a.out') or has sections without names (e.g., the Oasys format), the link cannot be done simply. You can circumvent this problem by describing the desired input-to-output section mapping with the linker command language. *Information can be lost during canonicalization.* The BFD internal canonical form of the external formats is not exhaustive; there are structures in input formats for which there is no direct representation internally. This means that the BFD back ends cannot maintain all possible data richness through the transformation between external to internal and back to external formats. This limitation is only a problem when an application reads one format and writes another. Each BFD back end is responsible for maintaining as much data as possible, and the internal BFD canonical form has structures which are opaque to the BFD core, and exported only to the back ends. When a file is read in one format, the canonical form is generated for BFD and the application. At the same time, the back end saves away any information which may otherwise be lost. If the data is then written back in the same format, the back end routine will be able to use the canonical form provided by the BFD core as well as the information it prepared earlier. Since there is a great deal of commonality between back ends, there is no information lost when linking or copying big endian COFF to little endian COFF, or `a.out' to `b.out'. When a mixture of formats is linked, the information is only lost from the files whose format differs from the destination. File: ld.info, Node: Canonical format, Prev: BFD information loss, Up: BFD outline The BFD canonical object-file format ------------------------------------ The greatest potential for loss of information occurs when there is the least overlap between the information provided by the source format, that stored by the canonical format, and that needed by the destination format. A brief description of the canonical form may help you understand which kinds of data you can count on preserving across conversions. *files* Information stored on a per-file basis includes target machine architecture, particular implementation format type, a demand pageable bit, and a write protected bit. Information like Unix magic numbers is not stored here--only the magic numbers' meaning, so a `ZMAGIC' file would have both the demand pageable bit and the write protected text bit set. The byte order of the target is stored on a per-file basis, so that big- and little-endian object files may be used with one another. *sections* Each section in the input file contains the name of the section, the section's original address in the object file, size and alignment information, various flags, and pointers into other BFD data structures. *symbols* Each symbol contains a pointer to the information for the object file which originally defined it, its name, its value, and various flag bits. When a BFD back end reads in a symbol table, it relocates all symbols to make them relative to the base of the section where they were defined. Doing this ensures that each symbol points to its containing section. Each symbol also has a varying amount of hidden private data for the BFD back end. Since the symbol points to the original file, the private data format for that symbol is accessible. `ld' can operate on a collection of symbols of wildly different formats without problems. Normal global and simple local symbols are maintained on output, so an output file (no matter its format) will retain symbols pointing to functions and to global, static, and common variables. Some symbol information is not worth retaining; in `a.out', type information is stored in the symbol table as long symbol names. This information would be useless to most COFF debuggers; the linker has command line switches to allow users to throw it away. There is one word of type information within the symbol, so if the format supports symbol type information within symbols (for example, COFF, IEEE, Oasys) and the type is simple enough to fit within one word (nearly everything but aggregates), the information will be preserved. *relocation level* Each canonical BFD relocation record contains a pointer to the symbol to relocate to, the offset of the data to relocate, the section the data is in, and a pointer to a relocation type descriptor. Relocation is performed by passing messages through the relocation type descriptor and the symbol pointer. Therefore, relocations can be performed on output data using a relocation method that is only available in one of the input formats. For instance, Oasys provides a byte relocation format. A relocation record requesting this relocation type would point indirectly to a routine to perform this, so the relocation may be performed on a byte being written to a 68k COFF file, even though 68k COFF has no such relocation type. *line numbers* Object formats can contain, for debugging purposes, some form of mapping between symbols, source line numbers, and addresses in the output file. These addresses have to be relocated along with the symbol information. Each symbol with an associated list of line number records points to the first record of the list. The head of a line number list consists of a pointer to the symbol, which allows finding out the address of the function whose line number is being described. The rest of the list is made up of pairs: offsets into the section and line numbers. Any format which can simply derive this information can pass it successfully between formats (COFF, IEEE and Oasys). File: ld.info, Node: MRI, Next: Index, Prev: BFD, Up: Top MRI Compatible Script Files *************************** To aid users making the transition to GNU `ld' from the MRI linker, `ld' can use MRI compatible linker scripts as an alternative to the more general-purpose linker scripting language described in *Note Command Language: Commands. MRI compatible linker scripts have a much simpler command set than the scripting language otherwise used with `ld'. GNU `ld' supports the most commonly used MRI linker commands; these commands are described here. In general, MRI scripts aren't of much use with the `a.out' object file format, since it only has three sections and MRI scripts lack some features to make use of them. You can specify a file containing an MRI-compatible script using the `-c' command-line option. Each command in an MRI-compatible script occupies its own line; each command line starts with the keyword that identifies the command (though blank lines are also allowed for punctuation). If a line of an MRI-compatible script begins with an unrecognized keyword, `ld' issues a warning message, but continues processing the script. Lines beginning with `*' are comments. You can write these commands using all upper-case letters, or all lower case; for example, `chip' is the same as `CHIP'. The following list shows only the upper-case form of each command. `ABSOLUTE SECNAME' `ABSOLUTE SECNAME, SECNAME, ... SECNAME' Normally, `ld' includes in the output file all sections from all the input files. However, in an MRI-compatible script, you can use the `ABSOLUTE' command to restrict the sections that will be present in your output program. If the `ABSOLUTE' command is used at all in a script, then only the sections named explicitly in `ABSOLUTE' commands will appear in the linker output. You can still use other input sections (whatever you select on the command line, or using `LOAD') to resolve addresses in the output file. `ALIAS OUT-SECNAME, IN-SECNAME' Use this command to place the data from input section IN-SECNAME in a section called OUT-SECNAME in the linker output file. IN-SECNAME may be an integer. `BASE EXPRESSION' Use the value of EXPRESSION as the lowest address (other than absolute addresses) in the output file. `CHIP EXPRESSION' `CHIP EXPRESSION, EXPRESSION' This command does nothing; it is accepted only for compatibility. `END' This command does nothing whatever; it's only accepted for compatibility. `FORMAT OUTPUT-FORMAT' Similar to the `OUTPUT_FORMAT' command in the more general linker language, but restricted to one of these output formats: 1. S-records, if OUTPUT-FORMAT is `S' 2. IEEE, if OUTPUT-FORMAT is `IEEE' 3. COFF (the `coff-m68k' variant in BFD), if OUTPUT-FORMAT is `COFF' `LIST ANYTHING...' Print (to the standard output file) a link map, as produced by the `ld' command-line option `-M'. The keyword `LIST' may be followed by anything on the same line, with no change in its effect. `LOAD FILENAME' `LOAD FILENAME, FILENAME, ... FILENAME' Include one or more object file FILENAME in the link; this has the same effect as specifying FILENAME directly on the `ld' command line. `NAME OUTPUT-NAME' OUTPUT-NAME is the name for the program produced by `ld'; the MRI-compatible command `NAME' is equivalent to the command-line option `-o' or the general script language command `OUTPUT'. `ORDER SECNAME, SECNAME, ... SECNAME' `ORDER SECNAME SECNAME SECNAME' Normally, `ld' orders the sections in its output file in the order in which they first appear in the input files. In an MRI-compatible script, you can override this ordering with the `ORDER' command. The sections you list with `ORDER' will appear first in your output file, in the order specified. `PUBLIC NAME=EXPRESSION' `PUBLIC NAME,EXPRESSION' `PUBLIC NAME EXPRESSION' Supply a value (EXPRESSION) for external symbol NAME used in the linker input files. `SECT SECNAME, EXPRESSION' `SECT SECNAME=EXPRESSION' `SECT SECNAME EXPRESSION' You can use any of these three forms of the `SECT' command to specify the start address (EXPRESSION) for section SECNAME. If you have more than one `SECT' statement for the same SECNAME, only the *first* sets the start address. File: ld.info, Node: Index, Prev: MRI, Up: Top Index ***** * Menu: * ": Symbols. * *( COMMON ): Section Placement. * *(SECTION): Section Placement. * -(: Options. * -verbose: Options. * -AARCH: Options. * -b FORMAT: Options. * -Bstatic: Options. * -c MRI-CMDFILE: Options. * -d: Options. * -dc: Options. * -defsym SYMBOL=EXP: Options. * -dp: Options. * -dynamic-linker FILE: Options. * -e ENTRY: Options. * -F: Options. * -format: Options. * -G: Options. * -g: Options. * -help: Options. * -i: Options. * -lARCHIVE: Options. * -LDIR: Options. * -M: Options. * -m EMULATION: Options. * -Map: Options. * -n: Options. * -N: Options. * -noinhibit-exec: Options. * -o OUTPUT: Options. * -oformat: Options. * -r: Options. * -R FILE: Options. * -relax: Options. * -rpath: Options. * -S: Options. * -s: Options. * -soname: Options. * -t: Options. * -T SCRIPT: Options. * -Tbss ORG: Options. * -Tdata ORG: Options. * -traditional-format: Options. * -Ttext ORG: Options. * -u SYMBOL: Options. * -Ur: Options. * -v: Options. * -V: Options. * -version: Options. * -warn-comon: Options. * -warn-once: Options. * -X: Options. * -x: Options. * -y SYMBOL: Options. * .: Location Counter. * 0x: Integers. * ;: Assignment. * =FILL: Section Options. * >REGION: Section Options. * -relax on i960: i960. * ABSOLUTE (MRI): MRI. * ALIAS (MRI): MRI. * BASE (MRI): MRI. * CHIP (MRI): MRI. * END (MRI): MRI. * FORMAT (MRI): MRI. * LIST (MRI): MRI. * LOAD (MRI): MRI. * NAME (MRI): MRI. * ORDER (MRI): MRI. * PUBLIC (MRI): MRI. * SECT (MRI): MRI. * [SECTION...], not supported: Section Placement. * FILENAME: Section Placement. * FILENAME(SECTION): Section Placement. * SYMBOL = EXPRESSION ;: Section Data Expressions. * SYMBOL F= EXPRESSION ;: Section Data Expressions. * absolute and relocatable symbols: Assignment. * ABSOLUTE(EXP): Arithmetic Functions. * ADDR(SECTION): Arithmetic Functions. * ALIGN(EXP): Arithmetic Functions. * aligning sections: Section Options. * allocating memory: MEMORY. * architectures: Options. * archive files, from cmd line: Options. * arithmetic: Expressions. * arithmetic operators: Operators. * assignment in scripts: Assignment. * assignment, in section defn: Section Data Expressions. * AT ( LDADR ): Section Options. * back end: BFD. * BFD canonical format: Canonical format. * BFD requirements: BFD. * binary input files: Option Commands. * binary input format: Options. * BLOCK(ALIGN): Section Options. * BYTE(EXPRESSION): Section Data Expressions. * C++ constructors, arranging in link: Option Commands. * combining symbols, warnings on: Options. * command files: Commands. * command line: Options. * commands, fundamental: Scripts. * comments: Scripts. * common allocation: Option Commands. * common allocation: Options. * commons in output: Section Placement. * compatibility, MRI: Options. * constructors: Options. * CONSTRUCTORS: Option Commands. * constructors, arranging in link: Option Commands. * contents of a section: Section Placement. * CREATE_OBJECT_SYMBOLS: Section Data Expressions. * current output location: Location Counter. * dbx: Options. * decimal integers: Integers. * default input format: Environment. * DEFINED(SYMBOL): Arithmetic Functions. * deleting local symbols: Options. * direct output: Section Data Expressions. * discontinuous memory: MEMORY. * dot: Location Counter. * dynamic linker, from command line: Options. * emulation: Options. * entry point, defaults: Entry Point. * entry point, from command line: Options. * ENTRY(SYMBOL): Entry Point. * expression evaluation order: Evaluation. * expression syntax: Expressions. * expression, absolute: Arithmetic Functions. * expressions in a section: Section Data Expressions. * filename symbols: Section Data Expressions. * files and sections, section defn: Section Placement. * files, including in output sections: Section Placement. * fill pattern, entire section: Section Options. * FILL(EXPRESSION): Section Data Expressions. * first input file: Option Commands. * first instruction: Entry Point. * FLOAT: Option Commands. * FORCE_COMMON_ALLOCATION: Option Commands. * format, output file: Option Commands. * functions in expression language: Arithmetic Functions. * fundamental script commands: Scripts. * GNU linker: Overview. * GNUTARGET: Option Commands. * GNUTARGET: Environment. * GROUP ( FILES ): Option Commands. * grouping input files: Option Commands. * groups of archives: Options. * H8/300 support: H8/300. * header size: Arithmetic Functions. * help: Options. * hexadecimal integers: Integers. * holes: Location Counter. * holes, filling: Section Data Expressions. * i960 support: i960. * incremental link: Options. * INPUT ( FILES ): Option Commands. * input file format: Option Commands. * input filename symbols: Section Data Expressions. * input files, displaying: Options. * input files, section defn: Section Placement. * input format: Options. * input format: Options. * input sections to output section: Section Placement. * integer notation: Integers. * integer suffixes: Integers. * internal object-file format: Canonical format. * K and M integer suffixes: Integers. * l =: MEMORY. * L, deleting symbols beginning: Options. * layout of output file: Scripts. * lazy evaluation: Evaluation. * len =: MEMORY. * LENGTH =: MEMORY. * link map: Options. * link map: Options. * load address, specifying: Section Options. * loading, preventing: Section Options. * local symbols, deleting: Options. * location counter: Location Counter. * LONG(EXPRESSION): Section Data Expressions. * M and K integer suffixes: Integers. * machine architecture, output: Option Commands. * machine dependencies: Machine Dependent. * MEMORY: MEMORY. * memory region attributes: MEMORY. * memory regions and sections: Section Options. * MRI compatibility: MRI. * names: Symbols. * naming memory regions: MEMORY. * naming output sections: Section Definition. * naming the output file: Option Commands. * naming the output file: Options. * negative integers: Integers. * NEXT(EXP): Arithmetic Functions. * NMAGIC: Options. * NOFLOAT: Option Commands. * NOLOAD: Section Options. * Non constant expression: Assignment. * o =: MEMORY. * objdump -i: BFD. * object file management: BFD. * object files: Options. * object formats available: BFD. * object size: Options. * octal integers: Integers. * OMAGIC: Options. * opening object files: BFD outline. * Operators for arithmetic: Operators. * options: Options. * org =: MEMORY. * ORIGIN =: MEMORY. * OUTPUT ( FILENAME ): Option Commands. * output file after errors: Options. * output file layout: Scripts. * OUTPUT_ARCH ( BFDNAME ): Option Commands. * OUTPUT_FORMAT ( BFDNAME ): Option Commands. * partial link: Options. * path for libraries: Option Commands. * precedence in expressions: Operators. * prevent unnecessary loading: Section Options. * provide: Assignment. * QUAD(EXPRESSION): Section Data Expressions. * quoted symbol names: Symbols. * read-only text: Options. * read/write from cmd line: Options. * regions of memory: MEMORY. * relaxing addressing modes: Options. * relaxing on H8/300: H8/300. * relaxing on i960: i960. * relocatable and absolute symbols: Assignment. * relocatable output: Options. * requirements for BFD: BFD. * retaining specified symbols: Options. * rounding up location counter: Arithmetic Functions. * runtime library name: Options. * runtime library search path: Options. * scaled integers: Integers. * script files: Options. * search directory, from cmd line: Options. * search path, libraries: Option Commands. * SEARCH_DIR ( PATH ): Option Commands. * section address: Arithmetic Functions. * section address: Section Options. * section alignment: Section Options. * section definition: Section Definition. * section defn, full syntax: Section Options. * section fill pattern: Section Options. * section size: Arithmetic Functions. * section start: Section Options. * section, assigning to memory region: Section Options. * SECTIONS: SECTIONS. * segment origins, cmd line: Options. * semicolon: Assignment. * SHORT(EXPRESSION): Section Data Expressions. * SIZEOF(SECTION): Arithmetic Functions. * sizeof_headers: Arithmetic Functions. * SIZEOF_HEADERS: Arithmetic Functions. * specify load address: Section Options. * standard Unix system: Options. * start address, section: Section Options. * start of execution: Entry Point. * STARTUP ( FILENAME ): Option Commands. * strip all symbols: Options. * strip debugger symbols: Options. * stripping all but some symbols: Options. * suffixes for integers: Integers. * symbol defaults: Arithmetic Functions. * symbol definition, scripts: Assignment. * symbol names: Symbols. * symbol tracing: Options. * symbol-only input: Options. * symbols, from command line: Options. * symbols, relocatable and absolute: Assignment. * symbols, retaining selectively: Options. * synthesizing linker: Options. * synthesizing on H8/300: H8/300. * TARGET ( FORMAT ): Option Commands. * traditional format: Options. * unallocated address, next: Arithmetic Functions. * undefined symbol: Options. * undefined symbols, warnings on: Options. * uninitialized data: Section Placement. * unspecified memory: Section Data Expressions. * usage: Options. * variables, defining: Assignment. * verbose: Options. * version: Options. * version: Options. * warnings, on combining symbols: Options. * warnings, on undefined symbols: Options. * what is this?: Overview.