those commands to make use of a compiler based plugin it must first be
copied into the @file{$@{libdir@}/bfd-plugins} directory. All gcc
based linker plugins are backward compatible, so it is sufficient to
-just copy in the newest one.
+just copy in the newest one.
@kindex --push-state
@cindex push state governing input file handling
The recognized keywords are:
@table @samp
+@item bndplt
+Always generate BND prefix in PLT entries. Supported for Linux/x86_64.
+
+@item call-nop=prefix-addr
+@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=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.
+
@item combreloc
-Combines multiple reloc sections and sorts them to make dynamic symbol
-lookup caching possible.
+@itemx nocombreloc
+Combine multiple dynamic relocation sections and sort to improve
+dynamic symbol lookup caching. Do not do this if @samp{nocombreloc}.
@item common
-Generate common symbols with the STT_COMMON type druing a relocatable
-link.
+@itemx nocommon
+Generate common symbols with STT_COMMON type during a relocatable
+link. Use STT_OBJECT type if @samp{nocommon}.
+
+@item common-page-size=@var{value}
+Set the page size most commonly used to @var{value}. Memory image
+layout will be optimized to minimize memory pages if the system is
+using pages of this size.
@item defs
Disallows undefined symbols in object files. Undefined symbols in
shared libraries are still allowed.
+@item dynamic-undefined-weak
+@itemx nodynamic-undefined-weak
+Make undefined weak symbols dynamic when building a dynamic object,
+if they are referenced from a regular object file and not forced local
+by symbol visibility or versioning. Do not make them dynamic if
+@samp{nodynamic-undefined-weak}. If neither option is given, a target
+may default to either option being in force, or make some other
+selection of undefined weak symbols dynamic. Not all targets support
+these options.
+
@item execstack
Marks the object as requiring executable stack.
setting the @code{DF_1_GLOBAUDIT} bit in the @code{DT_FLAGS_1} dynamic
tag. Global auditing requires that any auditing library defined via
the @option{--depaudit} or @option{-P} command line options be run for
-all dynamic objects loaded by the application.
+all dynamic objects loaded by the application.
+
+@item ibtplt
+Generate Intel Indirect Branch Tracking (IBT) enabled PLT entries.
+Supported for Linux/i386 and Linux/x86_64.
+
+@item ibt
+Generate GNU_PROPERTY_X86_FEATURE_1_IBT in .note.gnu.property section
+to indicate compatibility with IBT. This also implies @option{ibtplt}.
+Supported for Linux/i386 and Linux/x86_64.
@item initfirst
This option is only meaningful when building a shared object.
objects.
@item interpose
-Marks the object that its symbol table interposes before all symbols
-but the primary executable.
+Specify that the dynamic loader should modify its symbol search order
+so that symbols in this shared library interpose all other shared
+libraries not so marked.
@item lazy
When generating an executable or shared library, mark it to tell the
Lazy binding is the default.
@item loadfltr
-Marks the object that its filters be processed immediately at
-runtime.
+Specify that the object's filters be processed immediately at runtime.
-@item muldefs
-Allows multiple definitions.
-
-@item nocombreloc
-Disables multiple reloc sections combining.
+@item max-page-size=@var{value}
+Set the maximum memory page size supported to @var{value}.
-@item nocommon
-Generate common symbols with the STT_OBJECT type druing a relocatable
-link.
+@item muldefs
+Allow multiple definitions.
@item nocopyreloc
Disable linker generated .dynbss variables used in place of variables
defined in shared libraries. May result in dynamic text relocations.
@item nodefaultlib
-Marks the object that the search for dependencies of this object will
-ignore any default library search paths.
+Specify that the dynamic loader search for dependencies of this object
+should ignore any default library search paths.
@item nodelete
-Marks the object shouldn't be unloaded at runtime.
+Specify that the object shouldn't be unloaded at runtime.
@item nodlopen
-Marks the object not available to @code{dlopen}.
+Specify that the object is not available to @code{dlopen}.
@item nodump
-Marks the object can not be dumped by @code{dldump}.
+Specify that the object can not be dumped by @code{dldump}.
@item noexecstack
Marks the object as not requiring executable stack.
-@item text
-Treat DT_TEXTREL in shared object as error.
-
-@item notext
-Don't treat DT_TEXTREL in shared object as error.
-
-@item textoff
-Don't treat DT_TEXTREL in shared object as error.
-
-@item norelro
-Don't create an ELF @code{PT_GNU_RELRO} segment header in the object.
-
-@item now
-When generating an executable or shared library, mark it to tell the
-dynamic linker to resolve all symbols when the program is started, or
-when the shared library is linked to using dlopen, instead of
-deferring function call resolution to the point when the function is
-first called.
-
-@item origin
-Marks the object may contain $ORIGIN.
-
-@item relro
-Create an ELF @code{PT_GNU_RELRO} segment header in the object.
-
-@item max-page-size=@var{value}
-Set the emulation maximum page size to @var{value}.
-
-@item common-page-size=@var{value}
-Set the emulation common page size to @var{value}.
-
-@item stack-size=@var{value}
-Specify a stack size for in an ELF @code{PT_GNU_STACK} segment.
-Specifying zero will override any default non-zero sized
-@code{PT_GNU_STACK} segment creation.
-
-@item bndplt
-Always generate BND prefix in PLT entries. Supported for Linux/x86_64.
-
@item noextern-protected-data
-Don't treat protected data symbol as external when building shared
-library. This option overrides linker backend default. It can be used
-to workaround incorrect relocations against protected data symbols
+Don't treat protected data symbols as external when building a shared
+library. This option overrides the linker backend default. It can be
+used to work around incorrect relocations against protected data symbols
generated by compiler. Updates on protected data symbols by another
module aren't visible to the resulting shared library. Supported for
i386 and x86-64.
-@item dynamic-undefined-weak
-Make undefined weak symbols dynamic when building a dynamic object,
-if they are referenced from a regular object file and not forced local
-by symbol visibility or versioning. Not all targets support this
-option.
-
-@item nodynamic-undefined-weak
-Do not make undefined weak symbols dynamic when building a dynamic
-object. Not all targets support this option. If neither
-@option{-z nodynamic-undefined-weak} nor @option{-z dynamic-undefined-weak}
-are given, a target may default to either option being in force, or
-make some other selection of undefined weak symbols dynamic.
-
@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=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=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.
+@item now
+When generating an executable or shared library, mark it to tell the
+dynamic linker to resolve all symbols when the program is started, or
+when the shared library is loaded by dlopen, instead of deferring
+function call resolution to the point when the function is first
+called.
-@item ibtplt
-Generate Intel Indirect Branch Tracking (IBT) enabled PLT entries.
-Supported for Linux/i386 and Linux/x86_64.
+@item origin
+Specify that the object requires @samp{$ORIGIN} handling in paths.
-@item IBT
-Generate GNU_PROPERTY_X86_FEATURE_1_IBT in .note.gnu.property section
-to indicate compatibility with IBT. This also implies @option{ibtplt}.
-Supported for Linux/i386 and Linux/x86_64.
+@item relro
+@itemx norelro
+Create an ELF @code{PT_GNU_RELRO} segment header in the object. This
+specifies a memory segment that should be made read-only after
+relocation, if supported. Specifying @samp{common-page-size} smaller
+than the system page size will render this protection ineffective.
+Don't create an ELF @code{PT_GNU_RELRO} segment if @samp{norelro}.
@item shstk
Generate GNU_PROPERTY_X86_FEATURE_1_SHSTK in .note.gnu.property section
to indicate compatibility with Intel Shadow Stack. Supported for
Linux/i386 and Linux/x86_64.
+@item stack-size=@var{value}
+Specify a stack size for an ELF @code{PT_GNU_STACK} segment.
+Specifying zero will override any default non-zero sized
+@code{PT_GNU_STACK} segment creation.
+
+@item text
+@itemx notext
+@itemx textoff
+Report an error if DT_TEXTREL is set, i.e., if the binary has dynamic
+relocations in read-only sections. Don't report an error if
+@samp{notext} or @samp{textoff}.
+
@end table
Other keywords are ignored for Solaris compatibility.
This expression can only be used directly in @code{SECTIONS} commands, not in
any output section descriptions and only once in the linker script.
@var{commonpagesize} should be less or equal to @var{maxpagesize} and should
-be the system page size the object wants to be optimized for (while still
-working on system page sizes up to @var{maxpagesize}).
+be the system page size the object wants to be optimized for while still
+running on system page sizes up to @var{maxpagesize}. Note however
+that @samp{-z relro} protection will not be effective if the system
+page size is larger than @var{commonpagesize}.
@noindent
Example:
@samp{-z relro} option is used.
When @samp{-z relro} option is not present, @code{DATA_SEGMENT_RELRO_END}
does nothing, otherwise @code{DATA_SEGMENT_ALIGN} is padded so that
-@var{exp} + @var{offset} is aligned to the most commonly used page
-boundary for particular target. If present in the linker script,
-it must always come in between @code{DATA_SEGMENT_ALIGN} and
+@var{exp} + @var{offset} is aligned to the @var{commonpagesize}
+argument given to @code{DATA_SEGMENT_ALIGN}. If present in the linker
+script, it must be placed between @code{DATA_SEGMENT_ALIGN} and
@code{DATA_SEGMENT_END}. Evaluates to the second argument plus any
padding needed at the end of the @code{PT_GNU_RELRO} segment due to
section alignment.
@item --plt-align
@itemx --no-plt-align
Use these options to control whether individual PLT call stubs are
-padded so that they don't cross a 32-byte boundary, or to the
-specified power of two boundary when using @code{--plt-align=}. Note
-that this isn't alignment in the usual sense. By default PLT call
-stubs are packed tightly.
+aligned to a 32-byte boundary, or to the specified power of two
+boundary when using @code{--plt-align=}. A negative value may be
+specified to pad PLT call stubs so that they do not cross the
+specified power of two boundary (or the minimum number of boundaries
+if a PLT stub is so large that it must cross a boundary). By default
+PLT call stubs are aligned to 32-byte boundaries.
@cindex PowerPC64 PLT call stub static chain
@kindex --plt-static-chain
projects / binutils-gdb.git / blobdiff