\input texinfo
@setfilename ld.info
-@c Copyright (C) 1991-2019 Free Software Foundation, Inc.
+@c Copyright (C) 1991-2020 Free Software Foundation, Inc.
@syncodeindex ky cp
@c man begin INCLUDE
@include configdoc.texi
@end ifset
version @value{VERSION}.
-Copyright @copyright{} 1991-2019 Free Software Foundation, Inc.
+Copyright @copyright{} 1991-2020 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3
@vskip 0pt plus 1filll
@c man begin COPYRIGHT
-Copyright @copyright{} 1991-2019 Free Software Foundation, Inc.
+Copyright @copyright{} 1991-2020 Free Software Foundation, Inc.
Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.3
option is only meaningful on ELF platforms supporting the rtld-audit interface.
The -P option is provided for Solaris compatibility.
+@kindex --enable-non-contiguous-regions
+@item --enable-non-contiguous-regions
+This option avoids generating an error if an input section does not
+fit a matching output section. The linker tries to allocate the input
+section to subseque nt matching output sections, and generates an
+error only if no output section is large enough. This is useful when
+several non-contiguous memory regions are available and the input
+section does not require a particular one. The order in which input
+sections are evaluated does not change, for instance:
+
+@smallexample
+ MEMORY @{
+ MEM1 (rwx) : ORIGIN : 0x1000, LENGTH = 0x14
+ MEM2 (rwx) : ORIGIN : 0x1000, LENGTH = 0x40
+ MEM3 (rwx) : ORIGIN : 0x2000, LENGTH = 0x40
+ @}
+ SECTIONS @{
+ mem1 : @{ *(.data.*); @} > MEM1
+ mem2 : @{ *(.data.*); @} > MEM2
+ mem3 : @{ *(.data.*); @} > MEM2
+ @}
+
+ with input sections:
+ .data.1: size 8
+ .data.2: size 0x10
+ .data.3: size 4
+
+ results in .data.1 affected to mem1, and .data.2 and .data.3
+ affected to mem2, even though .data.3 would fit in mem3.
+@end smallexample
+
+This option is incompatible with INSERT statements because it changes
+the way input sections are mapped to output sections.
+
+@kindex --enable-non-contiguous-regions-warnings
+@item --enable-non-contiguous-regions-warnings
+This option enables warnings when
+@code{--enable-non-contiguous-regions} allows possibly unexpected
+matches in sections mapping, potentially leading to silently
+discarding a section instead of failing because it does not fit any
+output region.
+
@cindex entry point, from command line
@kindex -e @var{entry}
@kindex --entry=@var{entry}
The linker uses the following search paths to locate required shared
libraries:
+
@enumerate
@item
Any directories specified by @option{-rpath-link} options.
@item
The default directories, normally @file{/lib} and @file{/usr/lib}.
@item
-For a native linker on an ELF system, if the file @file{/etc/ld.so.conf}
-exists, the list of directories found in that file.
+For a linker for a Linux system, if the file @file{/etc/ld.so.conf}
+exists, the list of directories found in that file. Note: the path
+to this file is prefixed with the @code{sysroot} value, if that is
+defined, and then any @code{prefix} string if the linker was
+configured with the @command{--prefix=<path>} option.
+@item
+For a native linker on a FreeBSD system, any directories specified by
+the @code{_PATH_ELF_HINTS} macro defined in the @file{elf-hints.h}
+header file.
+@item
+Any directories specifed by a @code{SEARCH_DIR} command in the
+linker script being used.
@end enumerate
If the required shared library is not found, the linker will issue a
@item --high-entropy-va
Image is compatible with 64-bit address space layout randomization
(ASLR).
+This option also implies @option{--dynamicbase} and
+@option{--enable-reloc-section}.
@kindex --dynamicbase
@item --dynamicbase
The image base address may be relocated using address space layout
randomization (ASLR). This feature was introduced with MS Windows
Vista for i386 PE targets.
+This option also implies @option{--enable-reloc-section}.
@kindex --forceinteg
@item --forceinteg
can be used to insert a zero value for the timestamp, this ensuring
that binaries produced from identical sources will compare
identically.
+
+@kindex --enable-reloc-section
+@item --enable-reloc-section
+Create the base relocation table, which is necessary if the image
+is loaded at a different image base than specified in the PE header.
@end table
@c man end
input sections. Any input sections which are assigned to an output
section named @samp{/DISCARD/} are not included in the output file.
+Note, sections that match the @samp{/DISCARD/} output section will be
+discarded even if they are in an ELF section group which has other
+members which are not being discarded. This is deliberate.
+Discarding takes precedence over grouping.
+
@node Output Section Attributes
@subsection Output Section Attributes
@cindex output section attributes
@cindex PowerPC64 __tls_get_addr optimization
@kindex --tls-get-addr-optimize
@kindex --no-tls-get-addr-optimize
+@kindex --tls-get-addr-regsave
+@kindex --no-tls-get-addr-regsave
@item --tls-get-addr-optimize
@itemx --no-tls-get-addr-optimize
-These options control whether PowerPC64 @command{ld} uses a special
+These options control how PowerPC64 @command{ld} uses a special
stub to call __tls_get_addr. PowerPC64 glibc 2.22 and later support
an optimization that allows the second and subsequent calls to
@code{__tls_get_addr} for a given symbol to be resolved by the special
-stub without calling in to glibc. By default the linker enables this
-option when glibc advertises the availability of __tls_get_addr_opt.
-Forcing this option on when using an older glibc won't do much besides
-slow down your applications, but may be useful if linking an
-application against an older glibc with the expectation that it will
-normally be used on systems having a newer glibc.
+stub without calling in to glibc. By default the linker enables
+generation of the stub when glibc advertises the availability of
+__tls_get_addr_opt.
+Using @option{--tls-get-addr-optimize} with an older glibc won't do
+much besides slow down your applications, but may be useful if linking
+an application against an older glibc with the expectation that it
+will normally be used on systems having a newer glibc.
+@option{--tls-get-addr-regsave} forces generation of a stub that saves
+and restores volatile registers around the call into glibc. Normally,
+this is done when the linker detects a call to __tls_get_addr_desc.
+Such calls then go via the register saving stub to __tls_get_addr_opt.
+@option{--no-tls-get-addr-regsave} disables generation of the
+register saves.
@cindex PowerPC64 OPD optimization
@kindex --no-opd-optimize