ts, and with no Back-Cover Texts. A copy of the license is included in the section entitled \*(L"\s-1GNU\s0 Free Documentation License\*(R". .\" Automatically generated by Pod::Man 2.16 (Pod::Simple 3.05) .\" .\" Standard preamble: .\" ======================================================================== .de Sh \" Subsection heading .br .if t .Sp .ne 5 .PP \fB\\$1\fR .PP .. .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. 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Of course, you'll have to process the .\" output yourself in some meaningful fashion. .ie \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . nr % 0 . rr F .\} .el \{\ . de IX .. .\} .\" .\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2). .\" Fear. Run. Save yourself. 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Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" objdump \- display information from object files. .SH "SYNOPSIS" .IX Header "SYNOPSIS" objdump [\fB\-a\fR|\fB\-\-archive\-headers\fR] [\fB\-b\fR \fIbfdname\fR|\fB\-\-target=\fR\fIbfdname\fR] [\fB\-C\fR|\fB\-\-demangle\fR[=\fIstyle\fR] ] [\fB\-d\fR|\fB\-\-disassemble\fR] [\fB\-D\fR|\fB\-\-disassemble\-all\fR] [\fB\-z\fR|\fB\-\-disassemble\-zeroes\fR] [\fB\-EB\fR|\fB\-EL\fR|\fB\-\-endian=\fR{big | little }] [\fB\-f\fR|\fB\-\-file\-headers\fR] [\fB\-F\fR|\fB\-\-file\-offsets\fR] [\fB\-\-file\-start\-context\fR] [\fB\-g\fR|\fB\-\-debugging\fR] [\fB\-e\fR|\fB\-\-debugging\-tags\fR] [\fB\-h\fR|\fB\-\-section\-headers\fR|\fB\-\-headers\fR] [\fB\-i\fR|\fB\-\-info\fR] [\fB\-j\fR \fIsection\fR|\fB\-\-section=\fR\fIsection\fR] [\fB\-l\fR|\fB\-\-line\-numbers\fR] [\fB\-S\fR|\fB\-\-source\fR] [\fB\-m\fR \fImachine\fR|\fB\-\-architecture=\fR\fImachine\fR] [\fB\-M\fR \fIoptions\fR|\fB\-\-disassembler\-options=\fR\fIoptions\fR] [\fB\-p\fR|\fB\-\-private\-headers\fR] [\fB\-r\fR|\fB\-\-reloc\fR] [\fB\-R\fR|\fB\-\-dynamic\-reloc\fR] [\fB\-s\fR|\fB\-\-full\-contents\fR] [\fB\-W[lLiaprmfFsoRt]\fR| \fB\-\-dwarf\fR[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames\-interp,=str,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges]] [\fB\-G\fR|\fB\-\-stabs\fR] [\fB\-t\fR|\fB\-\-syms\fR] [\fB\-T\fR|\fB\-\-dynamic\-syms\fR] [\fB\-x\fR|\fB\-\-all\-headers\fR] [\fB\-w\fR|\fB\-\-wide\fR] [\fB\-\-start\-address=\fR\fIaddress\fR] [\fB\-\-stop\-address=\fR\fIaddress\fR] [\fB\-\-prefix\-addresses\fR] [\fB\-\-[no\-]show\-raw\-insn\fR] [\fB\-\-adjust\-vma=\fR\fIoffset\fR] [\fB\-\-special\-syms\fR] [\fB\-\-prefix=\fR\fIprefix\fR] [\fB\-\-prefix\-strip=\fR\fIlevel\fR] [\fB\-\-insn\-width=\fR\fIwidth\fR] [\fB\-V\fR|\fB\-\-version\fR] [\fB\-H\fR|\fB\-\-help\fR] \fIobjfile\fR... .SH "DESCRIPTION" .IX Header "DESCRIPTION" \&\fBobjdump\fR displays information about one or more object files. The options control what particular information to display. This information is mostly useful to programmers who are working on the compilation tools, as opposed to programmers who just want their program to compile and work. .PP \&\fIobjfile\fR... are the object files to be examined. When you specify archives, \fBobjdump\fR shows information on each of the member object files. .SH "OPTIONS" .IX Header "OPTIONS" The long and short forms of options, shown here as alternatives, are equivalent. At least one option from the list \&\fB\-a,\-d,\-D,\-e,\-f,\-g,\-G,\-h,\-H,\-p,\-r,\-R,\-s,\-S,\-t,\-T,\-V,\-x\fR must be given. .IP "\fB\-a\fR" 4 .IX Item "-a" .PD 0 .IP "\fB\-\-archive\-header\fR" 4 .IX Item "--archive-header" .PD If any of the \fIobjfile\fR files are archives, display the archive header information (in a format similar to \fBls \-l\fR). Besides the information you could list with \fBar tv\fR, \fBobjdump \-a\fR shows the object file format of each archive member. .IP "\fB\-\-adjust\-vma=\fR\fIoffset\fR" 4 .IX Item "--adjust-vma=offset" When dumping information, first add \fIoffset\fR to all the section addresses. This is useful if the section addresses do not correspond to the symbol table, which can happen when putting sections at particular addresses when using a format which can not represent section addresses, such as a.out. .IP "\fB\-b\fR \fIbfdname\fR" 4 .IX Item "-b bfdname" .PD 0 .IP "\fB\-\-target=\fR\fIbfdname\fR" 4 .IX Item "--target=bfdname" .PD Specify that the object-code format for the object files is \&\fIbfdname\fR. This option may not be necessary; \fIobjdump\fR can automatically recognize many formats. .Sp For example, .Sp .Vb 1 \& objdump \-b oasys \-m vax \-h fu.o .Ve .Sp displays summary information from the section headers (\fB\-h\fR) of \&\fIfu.o\fR, which is explicitly identified (\fB\-m\fR) as a \s-1VAX\s0 object file in the format produced by Oasys compilers. You can list the formats available with the \fB\-i\fR option. .IP "\fB\-C\fR" 4 .IX Item "-C" .PD 0 .IP "\fB\-\-demangle[=\fR\fIstyle\fR\fB]\fR" 4 .IX Item "--demangle[=style]" .PD Decode (\fIdemangle\fR) low-level symbol names into user-level names. Besides removing any initial underscore prepended by the system, this makes \*(C+ function names readable. Different compilers have different mangling styles. The optional demangling style argument can be used to choose an appropriate demangling style for your compiler. .IP "\fB\-g\fR" 4 .IX Item "-g" .PD 0 .IP "\fB\-\-debugging\fR" 4 .IX Item "--debugging" .PD Display debugging information. This attempts to parse \s-1STABS\s0 and \s-1IEEE\s0 debugging format information stored in the file and print it out using a C like syntax. If neither of these formats are found this option falls back on the \fB\-W\fR option to print any \s-1DWARF\s0 information in the file. .IP "\fB\-e\fR" 4 .IX Item "-e" .PD 0 .IP "\fB\-\-debugging\-tags\fR" 4 .IX Item "--debugging-tags" .PD Like \fB\-g\fR, but the information is generated in a format compatible with ctags tool. .IP "\fB\-d\fR" 4 .IX Item "-d" .PD 0 .IP "\fB\-\-disassemble\fR" 4 .IX Item "--disassemble" .PD Display the assembler mnemonics for the machine instructions from \&\fIobjfile\fR. This option only disassembles those sections which are expected to contain instructions. .IP "\fB\-D\fR" 4 .IX Item "-D" .PD 0 .IP "\fB\-\-disassemble\-all\fR" 4 .IX Item "--disassemble-all" .PD Like \fB\-d\fR, but disassemble the contents of all sections, not just those expected to contain instructions. .Sp If the target is an \s-1ARM\s0 architecture this switch also has the effect of forcing the disassembler to decode pieces of data found in code sections as if they were instructions. .IP "\fB\-\-prefix\-addresses\fR" 4 .IX Item "--prefix-addresses" When disassembling, print the complete address on each line. This is the older disassembly format. .IP "\fB\-EB\fR" 4 .IX Item "-EB" .PD 0 .IP "\fB\-EL\fR" 4 .IX Item "-EL" .IP "\fB\-\-endian={big|little}\fR" 4 .IX Item "--endian={big|little}" .PD Specify the endianness of the object files. This only affects disassembly. This can be useful when disassembling a file format which does not describe endianness information, such as S\-records. .IP "\fB\-f\fR" 4 .IX Item "-f" .PD 0 .IP "\fB\-\-file\-headers\fR" 4 .IX Item "--file-headers" .PD Display summary information from the overall header of each of the \fIobjfile\fR files. .IP "\fB\-F\fR" 4 .IX Item "-F" .PD 0 .IP "\fB\-\-file\-offsets\fR" 4 .IX Item "--file-offsets" .PD When disassembling sections, whenever a symbol is displayed, also display the file offset of the region of data that is about to be dumped. If zeroes are being skipped, then when disassembly resumes, tell the user how many zeroes were skipped and the file offset of the location from where the disassembly resumes. When dumping sections, display the file offset of the location from where the dump starts. .IP "\fB\-\-file\-start\-context\fR" 4 .IX Item "--file-start-context" Specify that when displaying interlisted source code/disassembly (assumes \fB\-S\fR) from a file that has not yet been displayed, extend the context to the start of the file. .IP "\fB\-h\fR" 4 .IX Item "-h" .PD 0 .IP "\fB\-\-section\-headers\fR" 4 .IX Item "--section-headers" .IP "\fB\-\-headers\fR" 4 .IX Item "--headers" .PD Display summary information from the section headers of the object file. .Sp File segments may be relocated to nonstandard addresses, for example by using the \fB\-Ttext\fR, \fB\-Tdata\fR, or \fB\-Tbss\fR options to \&\fBld\fR. However, some object file formats, such as a.out, do not store the starting address of the file segments. In those situations, although \fBld\fR relocates the sections correctly, using \fBobjdump \&\-h\fR to list the file section headers cannot show the correct addresses. Instead, it shows the usual addresses, which are implicit for the target. .IP "\fB\-H\fR" 4 .IX Item "-H" .PD 0 .IP "\fB\-\-help\fR" 4 .IX Item "--help" .PD Print a summary of the options to \fBobjdump\fR and exit. .IP "\fB\-i\fR" 4 .IX Item "-i" .PD 0 .IP "\fB\-\-info\fR" 4 .IX Item "--info" .PD Display a list showing all architecturesÎÔÏÔÐÔÑÔÒÔÓÔÔÔÕÔÖÔ×ÔØÔÙÔÚÔÛÔÜÔÝÔÞÔßÔ and object formats available for specification with \fB\-b\fR or \fB\-m\fR. .IP "\fB\-j\fR \fIname\fR" 4 .IX Item "-j name" .PD 0 .IP "\fB\-\-section=\fR\fIname\fR" 4 .IX Item "--section=name" .PD Display information only for section \fIname\fR. .IP "\fB\-l\fR" 4 .IX Item "-l" .PD 0 .IP "\fB\-\-line\-numbers\fR" 4 .IX Item "--line-numbers" .PD Label the display (using debugging information) with the filename and source line numbers corresponding to the object code or relocs shown. Only useful with \fB\-d\fR, \fB\-D\fR, or \fB\-r\fR. .IP "\fB\-m\fR \fImachine\fR" 4 .IX Item "-m machine" .PD 0 .IP "\fB\-\-architecture=\fR\fImachine\fR" 4 .IX Item "--architecture=machine" .PD Specify the architecture to use when disassembling object files. This can be useful when disassembling object files which do not describe architecture information, such as S\-records. You can list the available architectures with the \fB\-i\fR option. .Sp If the target is an \s-1ARM\s0 architecture then this switch has an additional effect. It restricts the disassembly to only those instructions supported by the architecture specified by \fImachine\fR. If it is necessary to use this switch because the input file does not contain any architecture information, but it is also desired to disassemble all the instructions use \fB\-marm\fR. .IP "\fB\-M\fR \fIoptions\fR" 4 .IX Item "-M options" .PD 0 .IP "\fB\-\-disassembler\-options=\fR\fIoptions\fR" 4 .IX Item "--disassembler-options=options" .PD Pass target specific information to the disassembler. Only supported on some targets. If it is necessary to specify more than one disassembler option then multiple \fB\-M\fR options can be used or can be placed together into a comma separated list. .Sp If the target is an \s-1ARM\s0 architecture then this switch can be used to select which register name set is used during disassembler. Specifying \&\fB\-M reg-names-std\fR (the default) will select the register names as used in \s-1ARM\s0's instruction set documentation, but with register 13 called \&'sp', register 14 called 'lr' and register 15 called 'pc'. Specifying \&\fB\-M reg-names-apcs\fR will select the name set used by the \s-1ARM\s0 Procedure Call Standard, whilst specifying \fB\-M reg-names-raw\fR will just use \fBr\fR followed by the register number. .Sp There are also two variants on the \s-1APCS\s0 register naming scheme enabled by \fB\-M reg-names-atpcs\fR and \fB\-M reg-names-special-atpcs\fR which use the ARM/Thumb Procedure Call Standard naming conventions. (Either with the normal register names or the special register names). .Sp This option can also be used for \s-1ARM\s0 architectures to force the disassembler to interpret all instructions as Thumb instructions by using the switch \fB\-\-disassembler\-options=force\-thumb\fR. This can be useful when attempting to disassemble thumb code produced by other compilers. .Sp For the x86, some of the options duplicate functions of the \fB\-m\fR switch, but allow finer grained control. Multiple selections from the following may be specified as a comma separated string. \&\fBx86\-64\fR, \fBi386\fR and \fBi8086\fR select disassembly for the given architecture. \fBintel\fR and \fBatt\fR select between intel syntax mode and \s-1AT&T\s0 syntax mode. \&\fBintel-mnemonic\fR and \fBatt-mnemonic\fR select between intel mnemonic mode and \s-1AT&T\s0 mnemonic mode. \fBintel-mnemonic\fR implies \fBintel\fR and \fBatt-mnemonic\fR implies \fBatt\fR. \&\fBaddr64\fR, \fBaddr32\fR, \&\fBaddr16\fR, \fBdata32\fR and \fBdata16\fR specify the default address size and operand size. These four options will be overridden if \&\fBx86\-64\fR, \fBi386\fR or \fBi8086\fR appear later in the option string. Lastly, \fBsuffix\fR, when in \s-1AT&T\s0 mode, instructs the disassembler to print a mnemonic suffix even when the suffix could be inferred by the operands. .Sp For PowerPC, \fBbooke\fR controls the disassembly of BookE instructions. \fB32\fR and \fB64\fR select PowerPC and PowerPC64 disassembly, respectively. \fBe300\fR selects disassembly for the e300 family. \fB440\fR selects disassembly for the PowerPC 440. \fBppcps\fR selects disassembly for the paired single instructions of the \s-1PPC750CL\s0. .Sp For \s-1MIPS\s0, this option controls the printing of instruction mnemonic names and register names in disassembled instructions. Multiple selections from the following may be specified as a comma separated string, and invalid options are ignored: .RS 4 .ie n .IP """no\-aliases""" 4 .el .IP "\f(CWno\-aliases\fR" 4 .IX Item "no-aliases" Print the 'raw' instruction mnemonic instead of some pseudo instruction mnemonic. I.e., print 'daddu' or 'or' instead of 'move', \&'sll' instead of 'nop', etc. .ie n .IP """gpr\-names=\f(CIABI\f(CW""" 4 .el .IP "\f(CWgpr\-names=\f(CIABI\f(CW\fR" 4 .IX Item "gpr-names=ABI" Print \s-1GPR\s0 (general-purpose register) names as appropriate for the specified \s-1ABI\s0. By default, \s-1GPR\s0 names are selected according to the \s-1ABI\s0 of the binary being disassembled. .ie n .IP """fpr\-names=\f(CIABI\f(CW""" 4 .el .IP "\f(CWfpr\-names=\f(CIABI\f(CW\fR" 4 .IX Item "fpr-names=ABI" Print \s-1FPR\s0 (floating-point register) names as appropriate for the specified \s-1ABI\s0. By default, \s-1FPR\s0 numbers are printed rather than names. .ie n .IP """cp0\-names=\f(CIARCH\f(CW""" 4 .el .IP "\f(CWcp0\-names=\f(CIARCH\f(CW\fR" 4 .IX Item "cp0-names=ARCH" Print \s-1CP0\s0 (system control coprocessor; coprocessor 0) register names as appropriate for the \s-1CPU\s0 or architecture specified by \&\fI\s-1ARCH\s0\fR. By default, \s-1CP0\s0 register names are selected according to the architecture and \s-1CPU\s0 of the binary being disassembled. .ie n .IP """hwr\-names=\f(CIARCH\f(CW""" 4 .el .IP "\f(CWhwr\-names=\f(CIARCH\f(CW\fR" 4 .IX Item "hwr-names=ARCH" Print \s-1HWR\s0 (hardware register, used by the \f(CW\*(C`rdhwr\*(C'\fR instruction) names as appropriate for the \s-1CPU\s0 or architecture specified by \&\fI\s-1ARCH\s0\fR. By default, \s-1HWR\s0 names are selected according to the architecture and \s-1CPU\s0 of the binary being disassembled. .ie n .IP """reg\-names=\f(CIABI\f(CW""" 4 .el .IP "\f(CWreg\-names=\f(CIABI\f(CW\fR" 4 .IX Item "reg-names=ABI" Print \s-1GPR\s0 and \s-1FPR\s0 names as appropriate for the selected \s-1ABI\s0. .ie n .IP """reg\-names=\f(CIARCH\f(CW""" 4 .el .IP "\f(CWreg\-names=\f(CIARCH\f(CW\fR" 4 .IX Item "reg-names=ARCH" Print CPU-specific register names (\s-1CP0\s0 register and \s-1HWR\s0 names) as appropriate for the selected \s-1CPU\s0 or architecture. .RE .RS 4 .Sp For any of the options listed above, \fI\s-1ABI\s0\fR or \&\fI\s-1ARCH\s0\fR may be specified as \fBnumeric\fR to have numbers printed rather than names, for the selected types of registers. You can list the available values of \fI\s-1ABI\s0\fR and \fI\s-1ARCH\s0\fR using the \fB\-\-help\fR option. .Sp For \s-1VAX\s0, you can specify function entry addresses with \fB\-M entry:0xf00ba\fR. You can use this multiple times to properly disassemble \s-1VAX\s0 binary files that don't contain symbol tables (like \&\s-1ROM\s0 dumps). In these cases, the function entry mask would otherwise be decoded as \s-1VAX\s0 instructions, which would probably lead the rest of the function being wrongly disassembled. .RE .IP "\fB\-p\fR" 4 .IX Item "-p" .PD 0 .IP "\fB\-\-private\-headers\fR" 4 .IX Item "--private-headers" .PD Print information that is specific to the object file format. The exact information printed depends upon the object file format. For some object file formats, no additional information is printed. .IP "\fB\-r\fR" 4 .IX Item "-r" .PD 0 .IP "\fB\-\-reloc\fR" 4 .IX Item "--reloc" .PD Print the relocation entries of the file. If used with \fB\-d\fR or \&\fB\-D\fR, the relocations are printed interspersed with the disassembly. .IP "\fB\-R\fR" 4 .IX Item "-R" .PD 0 .IP "\fB\-\-dynamic\-reloc\fR" 4 .IX Item "--dynamic-reloc" .PD Print the dynamic relocation entries of the file. This is only meaningful for dynamic objects, such as certain types of shared libraries. As for \fB\-r\fR, if used with \fB\-d\fR or \&\fB\-D\fR, the relocations are printed interspersed with the disassembly. .IP "\fB\-s\fR" 4 .IX Item "-s" .PD 0 .IP "\fB\-\-full\-contents\fR" 4 .IX Item "--full-contents" .PD Display the full contents of any sections requested. By default all non-empty sections are displayed. .IP "\fB\-S\fR" 4 .IX Item "-S" .PD 0 .IP "\fB\-\-source\fR" 4 .IX Item "--source" .PD Display source code intermixed with disassembly, if possible. Implies \&\fB\-d\fR. .IP "\fB\-\-prefix=\fR\fIprefix\fR" 4 .IX Item "--prefix=prefix" Specify \fIprefix\fR to add to the absolute paths when used with \&\fB\-S\fR. .IP "\fB\-\-prefix\-strip=\fR\fIlevel\fR" 4 .IX Item "--prefix-strip=level" Indicate how many initial directory names to strip off the hardwired absolute paths. It has no effect without \fB\-\-prefix=\fR\fIprefix\fR. .IP "\fB\-\-show\-raw\-insn\fR" 4 .IX Item "--show-raw-insn" When disassembling instructions, print the instruction in hex as well as in symbolic form. This is the default except when \&\fB\-\-prefix\-addresses\fR is used. .IP "\fB\-\-no\-show\-raw\-insn\fR" 4 .IX Item "--no-show-raw-insn" When disassembling instructions, do not print the instruction bytes. This is the default when \fB\-\-prefix\-addresses\fR is used. .IP "\fB\-\-insn\-width=\fR\fIwidth\fR" 4 .IX Item "--insn-width=width" Display \fIwidth\fR bytes on a single line when disassembling instructions. .IP "\fB\-W[lLiaprmfFsoRt]\fR" 4 .IX Item "-W[lLiaprmfFsoRt]" .PD 0 .IP "\fB\-\-dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames\-interp,=str,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges]\fR" 4 .IX Item "--dwarf[=rawline,=decodedline,=info,=abbrev,=pubnames,=aranges,=macro,=frames,=frames-interp,=str,=loc,=Ranges,=pubtypes,=trace_info,=trace_abbrev,=trace_aranges]" .PD Displays the contents of the debug sections in the file, if any are present. If one of the optional letters or words follows the switch then only data found in those specific sections will be dumped. .Sp Note that there is no single letter option to display the content of trace sections. .IP "\fB\-G\fR" 4 .IX Item "-G" .PD 0 .IP "\fB\-\-stabs\fR" 4 .IX Item "--stabs" .PD Display the full contents of any sections requested. Display the contents of the .stab and .stab.index and .stab.excl sections from an \&\s-1ELF\s0 file. This is only useful on systems (such as Solaris 2.0) in which \&\f(CW\*(C`.stab\*(C'\fR debugging symbol-table entries are carried in an \s-1ELF\s0 section. In most other file formats, debugging symbol-table entries are interleaved with linkage symbols, and are visible in the \fB\-\-syms\fR output. .IP "\fB\-\-start\-address=\fR\fIaddress\fR" 4 .IX Item "--start-address=address" Start displaying data at the specified address. This affects the output of the \fB\-d\fR, \fB\-r\fR and \fB\-s\fR options. .IP "\fB\-\-stop\-address=\fR\fIaddress\fR" 4 .IX Item "--stop-address=address" Stop displaying data at the specified address. This affects the output of the \fB\-d\fR, \fB\-r\fR and \fB\-s\fR options. .IP "\fB\-t\fR" 4 .IX Item "-t" .PD 0 .IP "\fB\-\-syms\fR" 4 .IX Item "--syms" .PD Print the symbol table entries of the file. This is similar to the information provided by the \fBnm\fR program, although the display format is different. The format of the output depends upon the format of the file being dumped, but there are two main types. One looks like this: .Sp .Vb 2 \& [ 4](sec 3)(fl 0x00)(ty 0)(scl 3) (nx 1) 0x00000000 .bss \& [ 6](sec 1)(fl 0x00)(ty 0)(scl 2) (nx 0) 0x00000000 fred .Ve .Sp where the number inside the square brackets is the number of the entry in the symbol table, the \fIsec\fR number is the section number, the \&\fIfl\fR value are the symbol's flag bits, the \fIty\fR number is the symbol's type, the \fIscl\fR number is the symbol's storage class and the \fInx\fR value is the number of auxilary entries associated with the symbol. The last two fields are the symbol's value and its name. .Sp The other common output format, usually seen with \s-1ELF\s0 based files, looks like this: .Sp .Vb 2 \& 00000000 l d .bss 00000000 .bss \& 00000000 g .text 00000000 fred .Ve .Sp Here the first number is the symbol's value (sometimes refered to as its address). The next field is actually a set of characters and spaces indicating the flag bits that are set on the symbol. These characters are described below. Next is the section with which the symbol is associated or \fI*ABS*\fR if the section is absolute (ie not connected with any section), or \fI*UND*\fR if the section is referenced in the file being dumped, but not defined there. .Sp After the section name comes another field, a number, which for common symbols is the alignment and for other symbol is the size. Finally the symbol's name is displayed. .Sp The flag characters are divided into 7 groups as follows: .RS 4 .ie n .IP """l""" 4 .el .IP "\f(CWl\fR" 4 .IX Item "l" .PD 0 .ie n .IP """g""" 4 .el .IP "\f(CWg\fR" 4 .IX Item "g" .ie n .IP """u""" 4 .el .IP "\f(CWu\fR" 4 .IX Item "u" .ie n .IP """!""" 4 .el .IP "\f(CW!\fR" 4 .IX Item "!" .PD The symbol is a local (l), global (g), unique global (u), neither global nor local (a space) or both global and local (!). A symbol can be neither local or global for a variety of reasons, e.g., because it is used for debugging, but it is probably an indication of a bug if it is ever both local and global. Unique global symbols are a \s-1GNU\s0 extension to the standard set of \s-1ELF\s0 symbol bindings. For such a symbol the dynamic linker will make sure that in the entire process there is just one symbol with this name and type in use. .ie n .IP """w""" 4 .el .IP "\f(CWw\fR" 4 .IX Item "w" The symbol is weak (w) or strong (a space). .ie n .IP """C""" 4 .el .IP "\f(CWC\fR" 4 .IX Item "C" The symbol denotes a constructor (C) or an ordinary symbol (a space). .ie n .IP """W""" 4 .el .IP "\f(CWW\fR" 4 .IX Item "W" The symbol is a warning (W) or a normal symbol (a space). A warning symbol's name is a message to be displayed if the symbol following the warning symbol is ever referenced. .ie n .IP """I""" 4 .el .IP "\f(CWI\fR" 4 .IX Item "I" .PD 0 .ie n .IP """i""" 4 .el .IP "\f(CWi\fR" 4 .IX Item "i" .PD The symbol is an indirect reference to another symbol (I), a function to be evaluated during reloc processing (i) or a normal symbol (a space). .ie n .IP """d""" 4 .el .IP "\f(CWd\fR" 4 .IX Item "d" .PD 0 .ie n .IP """D""" 4 .el .IP "\f(CWD\fR" 4 .IX Item "D" .PD The symbol is a debugging symbol (d) or a dynamic symbol (D) or a normal symbol (a space). .ie n .IP """F""" 4 .el .IP "\f(CWF\fR" 4 .IX Item "F" .PD 0 .ie n .IP """f""" 4 .el .IP "\f(CWf\fR" 4 .IX Item "f" .ie n .IP """O""" 4 .el .IP "\f(CWO\fR" 4 .IX Item "O" .PD The symbol is the name of a function (F) or a file (f) or an object (O) or just a normal symbol (a space). .RE .RS 4 .RE .IP "\fB\-T\fR" 4 .IX Item "-T" .PD 0 .IP "\fB\-\-dynamic\-syms\fR" 4 .IX Item "--dynamic-syms" .PD Print the dynamic symbol table entries of the file. This is only meaningful for dynamic objects, such as certain types of shared libraries. This is similar to the information provided by the \fBnm\fR program when given the \fB\-D\fR (\fB\-\-dynamic\fR) option. .IP "\fB\-\-special\-syms\fR" 4 .IX Item "--special-syms" When displaying symbols include those which the target considers to be special in some way and which would not normally be of interest to the user. .IP "\fB\-V\fR" 4 .IX Item "-V" .PD 0 .IP "\fB\-\-version\fR" 4 .IX Item "--version" .PD Print the version number of \fBobjdump\fR and exit. .IP "\fB\-x\fR" 4 .IX Item "-x" .PD 0 .IP "\fB\-\-all\-headers\fR" 4 .IX Item "--all-headers" .PD Display all available header information, including the symbol table and relocation entries. Using \fB\-x\fR is equivalent to specifying all of \&\fB\-a \-f \-h \-p \-r \-t\fR. .IP "\fB\-w\fR" 4 .IX Item "-w" .PD 0 .IP "\fB\-\-wide\fR" 4 .IX Item "--wide" .PD Format some lines for output devices that have more than 80 columns. Also do not truncate symbol names when they are displayed. .IP "\fB\-z\fR" 4 .IX Item "-z" .PD 0 .IP "\fB\-\-disassemble\-zeroes\fR" 4 .IX Item "--disassemble-zeroes" .PD Normally the disassembly output will skip blocks of zeroes. This option directs the disassembler to disassemble those blocks, just like any other data. .IP "\fB@\fR\fIfile\fR" 4 .IX Item "@file" Read command-line options from \fIfile\fR. The options read are inserted in place of the original @\fIfile\fR option. If \fIfile\fR does not exist, or cannot be read, then the option will be treated literally, and not removed. .Sp Options in \fIfile\fR are separated by whitespace. A whitespace character may be included in an option by surrounding the entire option in either single or double quotes. Any character (including a backslash) may be included by prefixing the character to be included with a backslash. The \fIfile\fR may itself contain additional @\fIfile\fR options; any such options will be processed recursively. .SH "SEE ALSO" .IX Header "SEE ALSO" \&\fInm\fR\|(1), \fIreadelf\fR\|(1), and the Info entries for \fIbinutils\fR. .SH "COPYRIGHT" .IX Header "COPYRIGHT" Copyright (c) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. .PP Permission is granted to copy, distribute and/or modify this document under the terms of the \s-1GNU\s0 Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, with no Front-Cover Texts, and with no Back-Cover Texts. A copy of the license is included in the section entitled \*(L"\s-1GNU\s0 Free Documentation License\*(R". .\" Automatically generated by Pod::Man 2.16 (Pod::Simple 3.05) .\" .\" Standard preamble: .\" ======================================================================== .de Sh \" Subsection heading .br .if t .Sp .ne 5 .PP \fB\\$1\fR .PP .. .de Sp \" Vertical space (when we can't use .PP) .if t .sp .5v .if n .sp .. .de Vb \" Begin verbatim text .ft CW .nf .ne \\$1 .. .de Ve \" End verbatim text .ft R .fi .. .\" Set up some character translations and predefined strings. \*(-- will .\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left .\" double quote, and \*(R" will give a right double quote. \*(C+ will .\" give a nicer C++. Capital omega is used to do unbreakable dashes and .\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff, .\" nothing in troff, for use with C<>. .tr \(*W- .ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p' .ie n \{\ . ds -- \(*W- . ds PI pi . if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch . if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\" diablo 12 pitch . ds L" "" . ds R" "" . ds C` "" . ds C' "" 'br\} .el\{\ . ds -- \|\(em\| . ds PI \(*p . ds L" `` . ds R" '' 'br\} .\" .\" Escape single quotes in literal strings from groff's Unicode transform. .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" .\" If the F register is turned on, we'll generate index entries on stderr for .\" titles (.TH), headers (.SH), subsections (.Sh), items (.Ip), and index .\" entries marked with X<> in POD. Of course, you'll have to process the .\" output yourself in some meaningful fashion. .ie \nF \{\ . de IX . tm Index:\\$1\t\\n%\t"\\$2" .. . nr % 0 . rr F .\} .el \{\ . de IX .. .\} .\" .\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2). .\" Fear. Run. Save yourself. No user-serviceable parts. . \" fudge factors for nroff and troff .if n \{\ . ds #H 0 . ds #V .8m . ds #F .3m . ds #[ \f1 . ds #] \fP .\} .if t \{\ . ds #H ((1u-(\\\\n(.fu%2u))*.13m) . ds #V .6m . ds #F 0 . ds #[ \& . ds #] \& .\} . \" simple accents for nroff and troff .if n \{\ . ds ' \& . ds ` \& . ds ^ \& . ds , \& . ds ~ ~ . ds / .\} .if t \{\ . ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u" . ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u' . ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u' . ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u' . ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u' . ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u' .\} . \" troff and (daisy-wheel) nroff accents .ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V' .ds 8 \h'\*(#H'\(*b\h'-\*(#H' .ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#] .ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H' .ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u' .ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#] .ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#] .ds ae a\h'-(\w'a'u*4/10)'e .ds Ae A\h'-(\w'A'u*4/10)'E . \" corrections for vroff .if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u' .if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u' . \" for low resolution devices (crt and lpr) .if \n(.H>23 .if \n(.V>19 \ \{\ . ds : e . ds 8 ss . ds o a . ds d- d\h'-1'\(ga . ds D- D\h'-1'\(hy . ds th \o'bp' . ds Th \o'LP' . ds ae ae . ds Ae AE .\} .rm #[ #] #H #V #F C .\" ======================================================================== .\" .IX Title "LD 1" .TH LD 1 "2010-12-08" "binutils-2.21" "GNU Development Tools" .\" For nroff, turn off justification. Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" ld \- The GNU linker .SH "SYNOPSIS" .IX Header "SYNOPSIS" ld [\fBoptions\fR] \fIobjfile\fR ... .SH "DESCRIPTION" .IX Header "DESCRIPTION" \&\fBld\fR combines a number of object and archive files, relocates their data and ties up symbol references. Usually the last step in compiling a program is to run \fBld\fR. .PP \&\fBld\fR accepts Linker Command Language files written in a superset of \s-1AT&T\s0's Link Editor Command Language syntax, to provide explicit and total control over the linking process. .PP This man page does not describe the command language; see the \&\fBld\fR entry in \f(CW\*(C`info\*(C'\fR for full details on the command language and on other aspects of the \s-1GNU\s0 linker. .PP This version of \fBld\fR uses the general purpose \s-1BFD\s0 libraries to operate on object files. This allows \fBld\fR to read, combine, and write object files in many different formats\-\-\-for example, \s-1COFF\s0 or \&\f(CW\*(C`a.out\*(C'\fR. Different formats may be linked together to produce any available kind of object file. .PP Aside from its flexibility, the \s-1GNU\s0 linker is more helpful than other linkers in providing diagnostic information. Many linkers abandon execution immediately upon encountering an error; whenever possible, \&\fBld\fR continues executing, allowing you to identify other errors (or, in some cases, to get an output file in spite of the error). .PP The \s-1GNU\s0 linker \fBld\fR is meant to cover a broad range of situations, and to be as compatible as possible with other linkers. As a result, you have many choices to control its behavior. .SH "OPTIONS" .IX Header "OPTIONS" The linker supports a plethora of command-line options, but in actual practice few of them are used in any particular context. For instance, a frequent use of \fBld\fR is to link standard Unix object files on a standard, supported Unix system. On such a system, to link a file \f(CW\*(C`hello.o\*(C'\fR: .PP .Vb 1 \& ld \-o /lib/crt0.o hello.o \-lc .Ve .PP This tells \fBld\fR to produce a file called \fIoutput\fR as the result of linking the file \f(CW\*(C`/lib/crt0.o\*(C'\fR with \f(CW\*(C`hello.o\*(C'\fR and the library \f(CW\*(C`libc.a\*(C'\fR, which will come from the standard search directories. (See the discussion of the \fB\-l\fR option below.) .PP Some of the command-line options to \fBld\fR may be specified at any point in the command line. However, options which refer to files, such as \fB\-l\fR or \fB\-T\fR, cause the file to be read at the point at which the option appears in the command line, relative to the object files and other file options. Repeating non-file options with a different argument will either have no further effect, or override prior occurrences (those further to the left on the command line) of that option. Options which may be meaningfully specified more than once are noted in the descriptions below. .PP Non-option arguments are object files or archives which are to be linked together. They may follow, precede, or be mixed in with command-line options, except that an object file argument may not be placed between an option and its argument. .PP Usually the linker is invoked with at least one object file, but you can specify other forms of binary input files using \fB\-l\fR, \fB\-R\fR, and the script command language. If \fIno\fR binary input files at all are specified, the linker does not produce any output, and issues the message \fBNo input files\fR. .PP If the linker cannot recognize the format of an object file, it will assume that it is a linker script. A script specified in this way augments the main linker script used for the link (either the default linker script or the one specified by using \fB\-T\fR). This feature permits the linker to link against a file which appears to be an object or an archive, but actually merely defines some symbol values, or uses \&\f(CW\*(C`INPUT\*(C'\fR or \f(CW\*(C`GROUP\*(C'\fR to load other objects. Specifying a script in this way merely augments the main linker script, with the extra commands placed after the main script; use the \fB\-T\fR option to replace the default linker script entirely, but note the effect of the \f(CW\*(C`INSERT\*(C'\fR command. .PP For options whose names are a single letter, option arguments must either follow the option letter without intervening whitespace, or be given as separate arguments immediately following the option that requires them. .PP For options whose names are multiple letters, either one dash or two can precede the option name; for example, \fB\-trace\-symbol\fR and \&\fB\-\-trace\-symbol\fR are equivalent. Note\-\-\-there is one exception to this rule. Multiple letter options that start with a lower case 'o' can only be preceded by two dashes. This is to reduce confusion with the \&\fB\-o\fR option. So for example \fB\-omagic\fR sets the output file name to \fBmagic\fR whereas \fB\-\-omagic\fR sets the \s-1NMAGIC\s0 flag on the output. .PP Arguments to multiple-letter options must either be separated from the option name by an equals sign, or be given as separate arguments immediately following the option that requires them. For example, \&\fB\-\-trace\-symbol foo\fR and \fB\-\-trace\-symbol=foo\fR are equivalent. Unique abbreviations of the names of multiple-letter options are accepted. .PP Note\-\-\-if the linker is being invoked indirectly, via a compiler driver (e.g. \fBgcc\fR) then all the linker command line options should be prefixed by \fB\-Wl,\fR (or whatever is appropriate for the particular compiler driver) like this: .PP .Vb 1 \& gcc \-Wl,\-\-start\-group foo.o bar.o \-Wl,\-\-end\-group .Ve .PP This is important, because otherwise the compiler driver program may silently drop the linker options, resulting in a bad link. Confusion may also arise when passing options that require values through a driver, as the use of a space between option and argument acts as a separator, and causes the driver to pass only the option to the linker and the argument to the compiler. In this case, it is simplest to use the joined forms of both single\- and multiple-letter options, such as: .PP .Vb 1 \& gcc foo.o bar.o \-Wl,\-eENTRY \-Wl,\-Map=a.map .Ve .PP Here is a table of the generic command line switches accepted by the \s-1GNU\s0 linker: .IP "\fB@\fR\fIfile\fR" 4 .IX Item "@file" Read command-line options from \fIfile\fR. The options read are inserted in place of the original @\fIfile\fR option. If \fIfile\fR does not exist, or cannot be read, then the option will be treated literally, and not removed. .Sp Options in \fIfile\fR are separated by whitespace. A whitespace character may be included in an option by surrounding the entire option in either single or double quotes. Any character (including a backslash) may be included by prefixing the character to be included with a backslash. The \fIfile\fR may itself contain additional @\fIfile\fR options; any such options will be processed recursively. .IP "\fB\-a\fR \fIkeyword\fR" 4 .IX Item "-a keyword" This option is supported for \s-1HP/UX\s0 compatibility. The \fIkeyword\fR argument must be one of the strings \fBarchive\fR, \fBshared\fR, or \&\fBdefault\fR. \fB\-aarchive\fR is functionally equivalent to \&\fB\-Bstatic\fR, and the other two keywords are functionally equivalent to \fB\-Bdynamic\fR. This option may be used any number of times. .IP "\fB\-\-audit\fR \fI\s-1AUDITLIB\s0\fR" 4 .IX Item "--audit AUDITLIB" Adds \fI\s-1AUDITLIB\s0\fR to the \f(CW\*(C`DT_AUDIT\*(C'\fR entry of the dynamic section. \&\fI\s-1AUDITLIB\s0\fR is not checked for existence, nor will it use the \s-1DT_SONAME\s0 specified in the library. If specified multiple times \f(CW\*(C`DT_AUDIT\*(C'\fR will contain a colon separated list of audit interfaces to use. If the linker finds an object with an audit entry while searching for shared libraries, it will add a corresponding \f(CW\*(C`DT_DEPAUDIT\*(C'\fR entry in the output file. This option is only meaningful on \s-1ELF\s0 platforms supporting the rtld-audit interface. .IP "\fB\-A\fR \fIarchitecture\fR" 4 .IX Item "-A architecture" .PD 0 .IP "\fB\-\-architecture=\fR\fIarchitecture\fR" 4 .IX Item "--architecture=architecture" .PD In the current release of \fBld\fR, this option is useful only for the Intel 960 family of architectures. In that \fBld\fR configuration, the \&\fIarchitecture\fR argument identifies the particular architecturíÔîÔïÔðÔñÔòÔóÔôÔõÔöÔ÷ÔøÔùÔúÔûÔüÔýÔþÔÿÔÕÕÕÕÕÕÕÕÕ Õ Õ Õ Õ ÕÕÕÕÕÕÕÕÕÕÕÕÕÕÕÕÕÕÕ Õ!Õ"Õ#Õ$Õ%Õ&Õ'Õ(Õ)Õ*Õ+Õ,Õ-Õ.Õ/Õ0Õ1Õ2Õ3Õ4Õ5Õ6Õ7Õ8Õ9Õ:Õ;Õ<Õ=Õ>Õ?Õ@ÕAÕBÕCÕDÕEÕFÕGÕHÕIÕJÕKÕLÕe in the 960 family, enabling some safeguards and modifying the archive-library search path. .Sp Future releases of \fBld\fR may support similar functionality for other architecture families. .IP "\fB\-b\fR \fIinput-format\fR" 4 .IX Item "-b input-format" .PD 0 .IP "\fB\-\-format=\fR\fIinput-format\fR" 4 .IX Item "--format=input-format" .PD \&\fBld\fR may be configured to support more than one kind of object file. If your \fBld\fR is configured this way, you can use the \&\fB\-b\fR option to specify the binary format for input object files that follow this option on the command line. Even when \fBld\fR is configured to support alternative object formats, you don't usually need to specify this, as \fBld\fR should be configured to expect as a default input format the most usual format on each machine. \&\fIinput-format\fR is a text string, the name of a particular format supported by the \s-1BFD\s0 libraries. (You can list the available binary formats with \fBobjdump \-i\fR.) .Sp You may want to use this option if you are linking files with an unusual binary format. You can also use \fB\-b\fR to switch formats explicitly (when linking object files of different formats), by including \&\fB\-b\fR \fIinput-format\fR before each group of object files in a particular format. .Sp The default format is taken from the environment variable \&\f(CW\*(C`GNUTARGET\*(C'\fR. .Sp You can also define the input format from a script, using the command \&\f(CW\*(C`TARGET\*(C'\fR; .IP "\fB\-c\fR \fIMRI-commandfile\fR" 4 .IX Item "-c MRI-commandfile" .PD 0 .IP "\fB\-\-mri\-script=\fR\fIMRI-commandfile\fR" 4 .IX Item "--mri-script=MRI-commandfile" .PD For compatibility with linkers produced by \s-1MRI\s0, \fBld\fR accepts script files written in an alternate, restricted command language, described in the \s-1MRI\s0 Compatible Script Files section of \s-1GNU\s0 ld documentation. Introduce \s-1MRI\s0 script files with the option \fB\-c\fR; use the \fB\-T\fR option to run linker scripts written in the general-purpose \fBld\fR scripting language. If \fIMRI-cmdfile\fR does not exist, \fBld\fR looks for it in the directories specified by any \fB\-L\fR options. .IP "\fB\-d\fR" 4 .IX Item "-d" .PD 0 .IP "\fB\-dc\fR" 4 .IX Item "-dc" .IP "\fB\-dp\fR" 4 .IX Item "-dp" .PD These three options are equivalent; multiple forms are supported for compatibility with other linkers. They assign space to common symbols even if a relocatable output file is specified (with \fB\-r\fR). The script command \f(CW\*(C`FORCE_COMMON_ALLOCATION\*(C'\fR has the same effect. .IP "\fB\-\-depaudit\fR \fI\s-1AUDITLIB\s0\fR" 4 .IX Item "--depaudit AUDITLIB" .PD 0 .IP "\fB\-P\fR \fI\s-1AUDITLIB\s0\fR" 4 .IX Item "-P AUDITLIB" .PD Adds \fI\s-1AUDITLIB\s0\fR to the \f(CW\*(C`DT_DEPAUDIT\*(C'\fR entry of the dynamic section. \&\fI\s-1AUDITLIB\s0\fR is not checked for existence, nor will it use the \s-1DT_SONAME\s0 specified in the library. If specified multiple times \f(CW\*(C`DT_DEPAUDIT\*(C'\fR will contain a colon separated list of audit interfaces to use. This option is only meaningful on \s-1ELF\s0 platforms supporting the rtld-audit interface. The \-P option is provided for Solaris compatibility. .IP "\fB\-e\fR \fIentry\fR" 4 .IX Item "-e entry" .PD 0 .IP "\fB\-\-entry=\fR\fIentry\fR" 4 .IX Item "--entry=entry" .PD Use \fIentry\fR as the explicit symbol for beginning execution of your program, rather than the default entry point. If there is no symbol named \fIentry\fR, the linker will try to parse \fIentry\fR as a number, and use that as the entry address (the number will be interpreted in base 10; you may use a leading \fB0x\fR for base 16, or a leading \&\fB0\fR for base 8). .IP "\fB\-\-exclude\-libs\fR \fIlib\fR\fB,\fR\fIlib\fR\fB,...\fR" 4 .IX Item "--exclude-libs lib,lib,..." Specifies a list of archive libraries from which symbols should not be automatically exported. The library names may be delimited by commas or colons. Specifying \&\f(CW\*(C`\-\-exclude\-libs ALL\*(C'\fR excludes symbols in all archive libraries from automatic export. This option is available only for the i386 \s-1PE\s0 targeted port of the linker and for \s-1ELF\s0 targeted ports. For i386 \s-1PE\s0, symbols explicitly listed in a .def file are still exported, regardless of this option. For \s-1ELF\s0 targeted ports, symbols affected by this option will be treated as hidden. .IP "\fB\-\-exclude\-modules\-for\-implib\fR \fImodule\fR\fB,\fR\fImodule\fR\fB,...\fR" 4 .IX Item "--exclude-modules-for-implib module,module,..." Specifies a list of object files or archive members, from which symbols should not be automatically exported, but which should be copied wholesale into the import library being generated during the link. The module names may be delimited by commas or colons, and must match exactly the filenames used by \fBld\fR to open the files; for archive members, this is simply the member name, but for object files the name listed must include and match precisely any path used to specify the input file on the linker's command-line. This option is available only for the i386 \s-1PE\s0 targeted port of the linker. Symbols explicitly listed in a .def file are still exported, regardless of this option. .IP "\fB\-E\fR" 4 .IX Item "-E" .PD 0 .IP "\fB\-\-export\-dynamic\fR" 4 .IX Item "--export-dynamic" .IP "\fB\-\-no\-export\-dynamic\fR" 4 .IX Item "--no-export-dynamic" .PD When creating a dynamically linked executable, using the \fB\-E\fR option or the \fB\-\-export\-dynamic\fR option causes the linker to add all symbols to the dynamic symbol table. The dynamic symbol table is the set of symbols which are visible from dynamic objects at run time. .Sp If you do not use either of these options (or use the \&\fB\-\-no\-export\-dynamic\fR option to restore the default behavior), the dynamic symbol table will normally contain only those symbols which are referenced by some dynamic object mentioned in the link. .Sp If you use \f(CW\*(C`dlopen\*(C'\fR to load a dynamic object which needs to refer back to the symbols defined by the program, rather than some other dynamic object, then you will probably need to use this option when linking the program itself. .Sp You can also use the dynamic list to control what symbols should be added to the dynamic symbol table if the output format supports it. See the description of \fB\-\-dynamic\-list\fR. .Sp Note that this option is specific to \s-1ELF\s0 targeted ports. \s-1PE\s0 targets support a similar function to export all symbols from a \s-1DLL\s0 or \s-1EXE\s0; see the description of \fB\-\-export\-all\-symbols\fR below. .IP "\fB\-EB\fR" 4 .IX Item "-EB" Link big-endian objects. This affects the default output format. .IP "\fB\-EL\fR" 4 .IX Item "-EL" Link little-endian objects. This affects the default output format. .IP "\fB\-f\fR \fIname\fR" 4 .IX Item "-f name" .PD 0 .IP "\fB\-\-auxiliary=\fR\fIname\fR" 4 .IX Item "--auxiliary=name" .PD When creating an \s-1ELF\s0 shared object, set the internal \s-1DT_AUXILIARY\s0 field to the specified name. This tells the dynamic linker that the symbol table of the shared object should be used as an auxiliary filter on the symbol table of the shared object \fIname\fR. .Sp If you later link a program against this filter object, then, when you run the program, the dynamic linker will see the \s-1DT_AUXILIARY\s0 field. If the dynamic linker resolves any symbols from the filter object, it will first check whether there is a definition in the shared object \&\fIname\fR. If there is one, it will be used instead of the definition in the filter object. The shared object \fIname\fR need not exist. Thus the shared object \fIname\fR may be used to provide an alternative implementation of certain functions, perhaps for debugging or for machine specific performance. .Sp This option may be specified more than once. The \s-1DT_AUXILIARY\s0 entries will be created in the order in which they appear on the command line. .IP "\fB\-F\fR \fIname\fR" 4 .IX Item "-F name" .PD 0 .IP "\fB\-\-filter=\fR\fIname\fR" 4 .IX Item "--filter=name" .PD When creating an \s-1ELF\s0 shared object, set the internal \s-1DT_FILTER\s0 field to the specified name. This tells the dynamic linker that the symbol table of the shared object which is being created should be used as a filter on the symbol table of the shared object \fIname\fR. .Sp If you later link a program against this filter object, then, when you run the program, the dynamic linker will see the \s-1DT_FILTER\s0 field. The dynamic linker will resolve symbols according to the symbol table of the filter object as usual, but it will actually link to the definitions found in the shared object \fIname\fR. Thus the filter object can be used to select a subset of the symbols provided by the object \&\fIname\fR. .Sp Some older linkers used the \fB\-F\fR option throughout a compilation toolchain for specifying object-file format for both input and output object files. The \s-1GNU\s0 linker uses other mechanisms for this purpose: the \&\fB\-b\fR, \fB\-\-format\fR, \fB\-\-oformat\fR options, the \&\f(CW\*(C`TARGET\*(C'\fR command in linker scripts, and the \f(CW\*(C`GNUTARGET\*(C'\fR environment variable. The \s-1GNU\s0 linker will ignore the \fB\-F\fR option when not creating an \s-1ELF\s0 shared object. .IP "\fB\-fini=\fR\fIname\fR" 4 .IX Item "-fini=name" When creating an \s-1ELF\s0 executable or shared object, call \s-1NAME\s0 when the executable or shared object is unloaded, by setting \s-1DT_FINI\s0 to the address of the function. By default, the linker uses \f(CW\*(C`_fini\*(C'\fR as the function to call. .IP "\fB\-g\fR" 4 .IX Item "-g" Ignored. Provided for compatibility with other tools. .IP "\fB\-G\fR \fIvalue\fR" 4 .IX Item "-G value" .PD 0 .IP "\fB\-\-gpsize=\fR\fIvalue\fR" 4 .IX Item "--gpsize=value" .PD Set the maximum size of objects to be optimized using the \s-1GP\s0 register to \&\fIsize\fR. This is only meaningful for object file formats such as \&\s-1MIPS\s0 \s-1ECOFF\s0 which supports putting large and small objects into different sections. This is ignored for other object file formats. .IP "\fB\-h\fR \fIname\fR" 4 .IX Item "-h name" .PD 0 .IP "\fB\-soname=\fR\fIname\fR" 4 .IX Item "-soname=name" .PD When creating an \s-1ELF\s0 shared object, set the internal \s-1DT_SONAME\s0 field to the specified name. When an executable is linked with a shared object which has a \s-1DT_SONAME\s0 field, then when the executable is run the dynamic linker will attempt to load the shared object specified by the \s-1DT_SONAME\s0 field rather than the using the file name given to the linker. .IP "\fB\-i\fR" 4 .IX Item "-i" Perform an incremental link (same as option \fB\-r\fR). .IP "\fB\-init=\fR\fIname\fR" 4 .IX Item "-init=name" When creating an \s-1ELF\s0 executable or shared object, call \s-1NAME\s0 when the executable or shared object is loaded, by setting \s-1DT_INIT\s0 to the address of the function. By default, the linker uses \f(CW\*(C`_init\*(C'\fR as the function to call. .IP "\fB\-l\fR \fInamespec\fR" 4 .IX Item "-l namespec" .PD 0 .IP "\fB\-\-library=\fR\fInamespec\fR" 4 .IX Item "--library=namespec" .PD Add the archive or object file specified by \fInamespec\fR to the list of files to link. This option may be used any number of times. If \fInamespec\fR is of the form \fI:\fIfilename\fI\fR, \fBld\fR will search the library path for a file called \fIfilename\fR, otherwise it will search the library path for a file called \fIlib\fInamespec\fI.a\fR. .Sp On systems which support shared libraries, \fBld\fR may also search for files other than \fIlib\fInamespec\fI.a\fR. Specifically, on \s-1ELF\s0 and SunOS systems, \fBld\fR will search a directory for a library called \fIlib\fInamespec\fI.so\fR before searching for one called \&\fIlib\fInamespec\fI.a\fR. (By convention, a \f(CW\*(C`.so\*(C'\fR extension indicates a shared library.) Note that this behavior does not apply to \fI:\fIfilename\fI\fR, which always specifies a file called \&\fIfilename\fR. .Sp The linker will search an archive only once, at the location where it is specified on the command line. If the archive defines a symbol which was undefined in some object which appeared before the archive on the command line, the linker will include the appropriate file(s) from the archive. However, an undefined symbol in an object appearing later on the command line will not cause the linker to search the archive again. .Sp See the \fB\-(\fR option for a way to force the linker to search archives multiple times. .Sp You may list the same archive multiple times on the command line. .Sp This type of archive searching is standard for Unix linkers. However, if you are using \fBld\fR on \s-1AIX\s0, note that it is different from the behaviour of the \s-1AIX\s0 linker. .IP "\fB\-L\fR \fIsearchdir\fR" 4 .IX Item "-L searchdir" .PD 0 .IP "\fB\-\-library\-path=\fR\fIsearchdir\fR" 4 .IX Item "--library-path=searchdir" .PD Add path \fIsearchdir\fR to the list of paths that \fBld\fR will search for archive libraries and \fBld\fR control scripts. You may use this option any number of times. The directories are searched in the order in which they are specified on the command line. Directories specified on the command line are searched before the default directories. All \&\fB\-L\fR options apply to all \fB\-l\fR options, regardless of the order in which the options appear. \fB\-L\fR options do not affect how \fBld\fR searches for a linker script unless \fB\-T\fR option is specified. .Sp If \fIsearchdir\fR begins with \f(CW\*(C`=\*(C'\fR, then the \f(CW\*(C`=\*(C'\fR will be replaced by the \fIsysroot prefix\fR, a path specified when the linker is configured. .Sp The default set of paths searched (without being specified with \&\fB\-L\fR) depends on which emulation mode \fBld\fR is using, and in some cases also on how it was configured. .Sp The paths can also be specified in a link script with the \&\f(CW\*(C`SEARCH_DIR\*(C'\fR command. Directories specified this way are searched at the point in which the linker script appears in the command line. .IP "\fB\-m\fR \fIemulation\fR" 4 .IX Item "-m emulation" Emulate the \fIemulation\fR linker. You can list the available emulations with the \fB\-\-verbose\fR or \fB\-V\fR options. .Sp If the \fB\-m\fR option is not used, the emulation is taken from the \&\f(CW\*(C`LDEMULATION\*(C'\fR environment variable, if that is defined. .Sp Otherwise, the default emulation depends upon how the linker was configured. .IP "\fB\-M\fR" 4 .IX Item "-M" .PD 0 .IP "\fB\-\-print\-map\fR" 4 .IX Item "--print-map" .PD Print a link map to the standard output. A link map provides information about the link, including the following: .RS 4 .IP "\(bu" 4 Where object files are mapped into memory. .IP "\(bu" 4 How common symbols are allocated. .IP "\(bu" 4 All archive members included in the link, with a mention of the symbol which caused the archive member to be brought in. .IP "\(bu" 4 The values assigned to symbols. .Sp Note \- symbols whose values are computed by an expression which involves a reference to a previous value of the same symbol may not have correct result displayed in the link map. This is because the linker discards intermediate results and only retains the final value of an expression. Under such circumstances the linker will display the final value enclosed by square brackets. Thus for example a linker script containing: .Sp .Vb 3 \& foo = 1 \& foo = foo * 4 \& foo = foo + 8 .Ve .Sp will produce the following output in the link map if the \fB\-M\fR option is used: .Sp .Vb 3 \& 0x00000001 foo = 0x1 \& [0x0000000c] foo = (foo * 0x4) \& [0x0000000c] foo = (foo + 0x8) .Ve .Sp See \fBExpressions\fR for more information about expressions in linker scripts. .RE .RS 4 .RE .IP "\fB\-n\fR" 4 .IX Item "-n" .PD 0 .IP "\fB\-\-nmagic\fR" 4 .IX Item "--nmagic" .PD Turn off page alignment of sections, and disable linking against shared libraries. If the output format supports Unix style magic numbers, mark the output as \f(CW\*(C`NMAGIC\*(C'\fR. .IP "\fB\-N\fR" 4 .IX Item "-N" .PD 0 .IP "\fB\-\-omagic\fR" 4 .IX Item "--omagic" .PD Set the text and data sections to be readable and writable. Also, do not page-align the data segment, and disable linking against shared libraries. If the output format supports Unix style magic numbers, mark the output as \f(CW\*(C`OMAGIC\*(C'\fR. Note: Although a writable text section is allowed for PE-COFF targets, it does not conform to the format specification published by Microsoft. .IP "\fB\-\-no\-omagic\fR" 4 .IX Item "--no-omagic" This option negates most of the effects of the \fB\-N\fR option. It sets the text section to be read-only, and forces the data segment to be page-aligned. Note \- this option does not enable linking against shared libraries. Use \fB\-Bdynamic\fR for this. .IP "\fB\-o\fR \fIoutput\fR" 4 .IX Item "-o output" .PD 0 .IP "\fB\-\-output=\fR\fIoutput\fR" 4 .IX Item "--output=output" .PD Use \fIoutput\fR as the name for the program produced by \fBld\fR; if this option is not specified, the name \fIa.out\fR is used by default. The script command \f(CW\*(C`OUTPUT\*(C'\fR can also specify the output file name. .IP "\fB\-O\fR \fIlevel\fR" 4 .IX Item "-O level" If \fIlevel\fR is a numeric values greater than zero \fBld\fR optimizes the output. This might take significantly longer and therefore probably should only be enabled for the final binary. At the moment this option only affects \s-1ELF\s0 shared library generation. Future releases of the linker may make more use of this option. Also currently there is no difference in the linker's behaviour for different non-zero values of this option. Again this may change with future releases. .IP "\fB\-q\fR" 4 .IX Item "-q" .PD 0 .IP "\fB\-\-emit\-relocs\fR" 4 .IX Item "--emit-relocs" .PD Leave relocation sections and contents in fully linked executables. Post link analysis and optimization tools may need this information in order to perform correct modifications of executables. This results in larger executables. .Sp This option is currently only supported on \s-1ELF\s0 platforms. .IP "\fB\-\-force\-dynamic\fR" 4 .IX Item "--force-dynamic" Force the output file to have dynamic sections. This option is specific to VxWorks targets. .IP "\fB\-r\fR" 4 .IX Item "-r" .PD 0 .IP "\fB\-\-relocatable\fR" 4 .IX Item "--relocatable" .PD Generate relocatable output\-\-\-i.e., generate an output file that can in turn serve as input to \fBld\fR. This is often called \fIpartial linking\fR. As a side effect, in environments that support standard Unix magic numbers, this option also sets the output file's magic number to \&\f(CW\*(C`OMAGIC\*(C'\fR. If this option is not specified, an absolute file is produced. When linking \*(C+ programs, this option \fIwill not\fR resolve references to constructors; to do that, use \fB\-Ur\fR. .Sp When an input file does not have the same format as the output file, partial linking is only supported if that input file does not contain any relocations. Different output formats can have further restrictions; for example some \f(CW\*(C`a.out\*(C'\fR\-based formats do not support partial linking with input files in other formats at all. .Sp This option does the same thing as \fB\-i\fR. .IP "\fB\-R\fR \fIfilename\fR" 4 .IX Item "-R