\input texinfo
@setfilename ld.info
-@c Copyright (C) 1991-2015 Free Software Foundation, Inc.
+@c Copyright (C) 1991-2016 Free Software Foundation, Inc.
@syncodeindex ky cp
@c man begin INCLUDE
@include configdoc.texi
@end ifset
version @value{VERSION}.
-Copyright @copyright{} 1991-2015 Free Software Foundation, Inc.
+Copyright @copyright{} 1991-2016 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{} 1991-2015 Free Software Foundation, Inc.
+Copyright @copyright{} 1991-2016 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
Combines multiple reloc sections and sorts them to make dynamic symbol
lookup caching possible.
+@item common
+Generate common symbols with the STT_COMMON type druing a relocatable
+link.
+
@item defs
Disallows undefined symbols in object files. Undefined symbols in
shared libraries are still allowed.
@item nocombreloc
Disables multiple reloc sections combining.
+@item nocommon
+Generate common symbols with the STT_OBJECT type druing a relocatable
+link.
+
@item nocopyreloc
Disable linker generated .dynbss variables used in place of variables
defined in shared libraries. May result in dynamic text relocations.
library. This option overrides linker backend default. It can be used
to workaround incorrect relocations against protected data symbols
generated by compiler. Updates on protected data symbols by another
-module aren't visibile to the resulting shared library. Supported for
+module aren't visible to the resulting shared library. Supported for
i386 and x86-64.
+@item nodynamic-undefined-weak
+Don't treat undefined weak symbols as dynamic when building executable.
+This option overrides linker backend default. It can be used to avoid
+dynamic relocations against undefined weak symbols in executable.
+Supported for i386 and x86-64.
+
+@item noreloc-overflow
+Disable relocation overflow check. This can be used to disable
+relocation overflow check if there will be no dynamic relocation
+overflow at run-time. Supported for x86_64.
+
+@item call-nop=prefix-addr
+@itemx call-nop=prefix-nop
+@itemx call-nop=suffix-nop
+@itemx call-nop=prefix-@var{byte}
+@itemx call-nop=suffix-@var{byte}
+Specify the 1-byte @code{NOP} padding when transforming indirect call
+to a locally defined function, foo, via its GOT slot.
+@option{call-nop=prefix-addr} generates @code{0x67 call foo}.
+@option{call-nop=prefix-nop} generates @code{0x90 call foo}.
+@option{call-nop=suffix-nop} generates @code{call foo 0x90}.
+@option{call-nop=prefix-@var{byte}} generates @code{@var{byte} call foo}.
+@option{call-nop=suffix-@var{byte}} generates @code{call foo @var{byte}}.
+Supported for i386 and x86_64.
+
@end table
Other keywords are ignored for Solaris compatibility.
When creating a shared library, bind references to global symbols to the
definition within the shared library, if any. Normally, it is possible
for a program linked against a shared library to override the definition
-within the shared library. This option is only meaningful on ELF
-platforms which support shared libraries.
+within the shared library. This option can also be used with the
+@option{--export-dynamic} option, when creating a position independent
+executable, to bind references to global symbols to the definition within
+the executable. This option is only meaningful on ELF platforms which
+support shared libraries and position independent executables.
@kindex -Bsymbolic-functions
@item -Bsymbolic-functions
When creating a shared library, bind references to global function
symbols to the definition within the shared library, if any.
+This option can also be used with the @option{--export-dynamic} option,
+when creating a position independent executable, to bind references
+to global function symbols to the definition within the executable.
This option is only meaningful on ELF platforms which support shared
-libraries.
+libraries and position independent executables.
@kindex --dynamic-list=@var{dynamic-list-file}
@item --dynamic-list=@var{dynamic-list-file}
this option overrides it. @xref{BFD}.
@end ifclear
+@kindex --out-implib
+@item --out-implib @var{file}
+Create an import library in @var{file} corresponding to the executable
+the linker is generating (eg. a DLL or ELF program). This import
+library (which should be called @code{*.dll.a} or @code{*.a} for DLLs)
+may be used to link clients against the generated executable; this
+behaviour makes it possible to skip a separate import library creation
+step (eg. @code{dlltool} for DLLs). This option is only available for
+the i386 PE and ELF targetted ports of the linker.
+
@kindex -pie
@kindex --pic-executable
@item -pie
@code{LD_RUN_PATH} will be used if it is defined.
The @option{-rpath} option may also be used on SunOS. By default, on
-SunOS, the linker will form a runtime search patch out of all the
+SunOS, the linker will form a runtime search path out of all the
@option{-L} options it is given. If a @option{-rpath} option is used, the
runtime search path will be formed exclusively using the @option{-rpath}
options, ignoring the @option{-L} options. This can be useful when using
instead of @samp{.debug}. @option{--compress-debug-sections=zlib}
and @option{--compress-debug-sections=zlib-gabi}
compress DWARF debug sections with SHF_COMPRESSED from the ELF ABI.
+The default behaviour varies depending upon the target involved and
+the configure options used to build the toolchain. The default can be
+determined by examing the output from the linker's @option{--help} option.
@kindex --reduce-memory-overheads
@item --reduce-memory-overheads
[This option is specific to the i386 PE targeted port of the linker]
@cindex DLLs, creating
-@kindex --out-implib
-@item --out-implib @var{file}
-The linker will create the file @var{file} which will contain an
-import lib corresponding to the DLL the linker is generating. This
-import lib (which should be called @code{*.dll.a} or @code{*.a}
-may be used to link clients against the generated DLL; this behaviour
-makes it possible to skip a separate @code{dlltool} import library
-creation step.
-[This option is specific to the i386 PE targeted port of the linker]
-
@kindex --enable-auto-image-base
@item --enable-auto-image-base
@itemx --enable-auto-image-base=@var{value}
@code{NOCROSSREFS} command uses output section names, not input section
names.
+@item NOCROSSREFS_TO(@var{tosection} @var{fromsection} @dots{})
+@kindex NOCROSSREFS_TO(@var{tosection} @var{fromsections})
+@cindex cross references
+This command may be used to tell @command{ld} to issue an error about any
+references to one section from a list of other sections.
+
+The @code{NOCROSSREFS} command is useful when ensuring that two or more
+output sections are entirely independent but there are situations where
+a one-way dependency is needed. For example, in a multi-core application
+there may be shared code that can be called from each core but for safety
+must never call back.
+
+The @code{NOCROSSREFS_TO} command takes a list of output section names.
+The first section can not be referenced from any of the other sections.
+If @command{ld} detects any references to the first section from any of
+the other sections, it reports an error and returns a non-zero exit
+status. Note that the @code{NOCROSSREFS_TO} command uses output section
+names, not input section names.
+
@ifclear SingleFormat
@item OUTPUT_ARCH(@var{bfdarch})
@kindex OUTPUT_ARCH(@var{bfdarch})
@end smallexample
or
@smallexample
-(ALIGN(@var{maxpagesize}) + (. & (@var{maxpagesize} - @var{commonpagesize})))
+(ALIGN(@var{maxpagesize})
+ + ((. + @var{commonpagesize} - 1) & (@var{maxpagesize} - @var{commonpagesize})))
@end smallexample
@noindent
depending on whether the latter uses fewer @var{commonpagesize} sized pages
Programmer Advice Notice'' available on the ARM documentation website at:
http://infocenter.arm.com/.
+@cindex STM32L4xx erratum workaround
+@kindex --fix-stm32l4xx-629360
+
+The @samp{--fix-stm32l4xx-629360} switch enables a link-time
+workaround for a bug in the bus matrix / memory controller for some of
+the STM32 Cortex-M4 based products (STM32L4xx). When accessing
+off-chip memory via the affected bus for bus reads of 9 words or more,
+the bus can generate corrupt data and/or abort. These are only
+core-initiated accesses (not DMA), and might affect any access:
+integer loads such as LDM, POP and floating-point loads such as VLDM,
+VPOP. Stores are not affected.
+
+The bug can be avoided by splitting memory accesses into the
+necessary chunks to keep bus reads below 8 words.
+
+The workaround is not enabled by default, this is equivalent to use
+@samp{--fix-stm32l4xx-629360=none}. If you know you are using buggy
+STM32L4xx hardware, you can enable the workaround by specifying the
+linker option @samp{--fix-stm32l4xx-629360}, or the equivalent
+@samp{--fix-stm32l4xx-629360=default}.
+
+If the workaround is enabled, instructions are scanned for
+potentially-troublesome sequences, and a veneer is created for each
+such sequence which may trigger the erratum. The veneer consists in a
+replacement sequence emulating the behaviour of the original one and a
+branch back to the subsequent instruction. The original instruction is
+then replaced with a branch to the veneer.
+
+The workaround does not always preserve the memory access order for
+the LDMDB instruction, when the instruction loads the PC.
+
+The workaround is not able to handle problematic instructions when
+they are in the middle of an IT block, since a branch is not allowed
+there. In that case, the linker reports a warning and no replacement
+occurs.
+
+The workaround is not able to replace problematic instructions with a
+PC-relative branch instruction if the @samp{.text} section is too
+large. In that case, when the branch that replaces the original code
+cannot be encoded, the linker reports a warning and no replacement
+occurs.
+
@cindex NO_ENUM_SIZE_WARNING
@kindex --no-enum-size-warning
The @option{--no-enum-size-warning} switch prevents the linker from
which support up to 4Gb of code. The default is to use 12 byte PLT
entries which only support 512Mb of code.
+@kindex --no-apply-dynamic-relocs
+@cindex AArch64 rela addend
+The @samp{--no-apply-dynamic-relocs} option makes AArch64 linker do not apply
+link-time values for dynamic relocations.
+
@ifclear GENERIC
@lowersections
@end ifclear
projects / deliverable / binutils-gdb.git / blobdiff