2014-02-11 Andrew Pinski <apinski@cavium.com>

[binutils-gdb.git] / ld / ld.texinfo

diff --git a/ld/ld.texinfo b/ld/ld.texinfo
index ae3d568721d522865a2564ae717c3ebbcf5f5f89..bfc264378dbc0a07f378eec904ca53c8b8c59ab5 100644 (file)
--- a/ld/ld.texinfo
+++ b/ld/ld.texinfo
@@ -30,6 +30,7 @@
 @set MMIX
 @set MSP430
 @set NDS32
+@set NIOSII
 @set POWERPC
 @set POWERPC64
 @set Renesas
@@ -1605,6 +1606,9 @@ This option is only supported on a few targets.
 @ifset M68HC11
 @xref{M68HC11/68HC12,,@command{ld} and the 68HC11 and 68HC12}.
 @end ifset
+@ifset NIOSII
+@xref{Nios II,,@command{ld} and the Altera Nios II}.
+@end ifset
 @ifset POWERPC
 @xref{PowerPC ELF32,,@command{ld} and PowerPC 32-bit ELF Support}.
 @end ifset
@@ -4406,9 +4410,9 @@ scripts.
 @cindex discarding sections
 @cindex sections, discarding
 @cindex removing sections
-The linker will not create output sections with no contents.  This is
-for convenience when referring to input sections that may or may not
-be present in any of the input files.  For example:
+The linker will not normally create output sections with no contents.
+This is for convenience when referring to input sections that may or
+may not be present in any of the input files.  For example:
 @smallexample
 .foo : @{ *(.foo) @}
 @end smallexample
@@ -4416,7 +4420,12 @@ be present in any of the input files.  For example:
 will only create a @samp{.foo} section in the output file if there is a
 @samp{.foo} section in at least one input file, and if the input
 sections are not all empty.  Other link script directives that allocate
-space in an output section will also create the output section.
+space in an output section will also create the output section.  So
+too will assignments to dot even if the assignment does not create
+space, except for @samp{. = 0}, @samp{. = . + 0}, @samp{. = sym},
+@samp{. = . + sym} and @samp{. = ALIGN (. != 0, expr, 1)} when
+@samp{sym} is an absolute symbol of value 0 defined in the script.
+This allows you to force output of an empty section with @samp{. = .}.
 
 The linker will ignore address assignments (@pxref{Output Section Address})
 on discarded output sections, except when the linker script defines
@@ -4600,10 +4609,8 @@ for (dst = &_bstart; dst< &_bend; dst++)
 @cindex forcing output section alignment
 @cindex output section alignment
 You can increase an output section's alignment by using ALIGN.  As an
-alternative you can force the output section alignment to the maximum alignment
-of all its input sections with ALIGN_WITH_INPUT.  The alignment forced by
-ALIGN_WITH_INPUT is used even in case the load and virtual memory regions are
-different.
+alternative you can enforce that the difference between the VMA and LMA remains
+intact throughout this output section with the ALIGN_WITH_INPUT attribute.
 
 @node Forced Input Alignment
 @subsubsection Forced Input Alignment
@@ -6100,6 +6107,9 @@ functionality are not listed.
 @ifset NDS32
 * NDS32::                      @command{ld} and NDS32
 @end ifset
+@ifset NIOSII
+* Nios II::                    @command{ld} and the Altera Nios II
+@end ifset
 @ifset POWERPC
 * PowerPC ELF32::              @command{ld} and PowerPC 32-bit ELF Support
 @end ifset
@@ -6738,6 +6748,43 @@ Avoid generating the IFC instruction inside the loop.
 @end ifclear
 @end ifset
 
+@ifset NIOSII
+@ifclear GENERIC
+@raisesections
+@end ifclear
+
+@node Nios II
+@section @command{ld} and the Altera Nios II
+@cindex Nios II call relaxation
+@kindex --relax on Nios II
+
+Call and immediate jump instructions on Nios II processors are limited to
+transferring control to addresses in the same 256MB memory segment,
+which may result in @command{ld} giving
+@samp{relocation truncated to fit} errors with very large programs.
+The command-line option @option{--relax} enables the generation of
+trampolines that can access the entire 32-bit address space for calls
+outside the normal @code{call} and @code{jmpi} address range.  These
+trampolines are inserted at section boundaries, so may not themselves
+be reachable if an input section and its associated call trampolines are
+larger than 256MB.
+
+The @option{--relax} option is enabled by default unless @option{-r}
+is also specified.  You can disable trampoline generation by using the
+@option{--no-relax} linker option.  You can also disable this optimization
+locally by using the @samp{set .noat} directive in assembly-language
+source files, as the linker-inserted trampolines use the @code{at}
+register as a temporary.
+
+Note that the linker @option{--relax} option is independent of assembler
+relaxation options, and that using the GNU assembler's @option{-relax-all}
+option interferes with the linker's more selective call instruction relaxation.
+
+@ifclear GENERIC
+@lowersections
+@end ifclear
+@end ifset
+
 @ifset POWERPC
 @ifclear GENERIC
 @raisesections