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authorNick Clifton <nickc@redhat.com>2003-04-01 15:50:31 +0000
committerNick Clifton <nickc@redhat.com>2003-04-01 15:50:31 +0000
commite0001a05d2e4967ee86f4468cdc4fafea66b92d1 (patch)
tree4676b72e452f4dfc81e8d6646fb43f63a108da1b /ld/ld.texinfo
parentce0c72625ad0f6497718b4293572b2b6be711714 (diff)
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Add Xtensa port
Diffstat (limited to 'ld/ld.texinfo')
-rw-r--r--ld/ld.texinfo77
1 files changed, 76 insertions, 1 deletions
diff --git a/ld/ld.texinfo b/ld/ld.texinfo
index 96a87f4..ce9bf90 100644
--- a/ld/ld.texinfo
+++ b/ld/ld.texinfo
@@ -45,6 +45,7 @@
@set V850
@set VAX
@set WIN32
+@set XTENSA
@end ifset
@c man end
@@ -157,6 +158,9 @@ section entitled ``GNU Free Documentation License''.
@ifset WIN32
* Win32:: ld and WIN32 (cygwin/mingw)
@end ifset
+@ifset XTENSA
+* Xtensa:: ld and Xtensa Processors
+@end ifset
@end ifclear
@ifclear SingleFormat
* BFD:: BFD
@@ -1227,7 +1231,9 @@ This option is only supported on a few targets.
@ifset I960
@xref{i960,, @command{ld} and the Intel 960 family}.
@end ifset
-
+@ifset XTENSA
+@xref{Xtensa,, @command{ld} and Xtensa Processors}.
+@end ifset
On some platforms, the @samp{--relax} option performs global
optimizations that become possible when the linker resolves addressing
@@ -4446,6 +4452,9 @@ functionality are not listed.
@ifset WIN32
* WIN32:: @command{ld} and WIN32 (cygwin/mingw)
@end ifset
+@ifset XTENSA
+* Xtensa:: @command{ld} and Xtensa Processors
+@end ifset
@end menu
@end ifset
@@ -5077,6 +5086,72 @@ which is probably not what you wanted.
@end ifclear
@end ifset
+@ifset XTENSA
+@ifclear GENERIC
+@raisesections
+@end ifclear
+
+@node Xtensa
+@section @code{ld} and Xtensa Processors
+
+@cindex Xtensa processors
+The default @command{ld} behavior for Xtensa processors is to interpret
+@code{SECTIONS} commands so that lists of explicitly named sections in a
+specification with a wildcard file will be interleaved when necessary to
+keep literal pools within the range of PC-relative load offsets. For
+example, with the command:
+
+@smallexample
+SECTIONS
+@{
+ .text : @{
+ *(.literal .text)
+ @}
+@}
+@end smallexample
+
+@noindent
+@command{ld} may interleave some of the @code{.literal}
+and @code{.text} sections from different object files to ensure that the
+literal pools are within the range of PC-relative load offsets. A valid
+interleaving might place the @code{.literal} sections from an initial
+group of files followed by the @code{.text} sections of that group of
+files. Then, the @code{.literal} sections from the rest of the files
+and the @code{.text} sections from the rest of the files would follow.
+The non-interleaved order can still be specified as:
+
+@smallexample
+SECTIONS
+@{
+ .text : @{
+ *(.literal) *(.text)
+ @}
+@}
+@end smallexample
+
+@cindex @code{--relax} on Xtensa
+@cindex relaxing on Xtensa
+@kindex --no-relax
+The Xtensa version of @command{ld} enables the @option{--relax} option by
+default to attempt to reduce space in the output image by combining
+literals with identical values. It also provides the
+@option{--no-relax} option to disable this optimization. When enabled,
+the relaxation algorithm ensures that a literal will only be merged with
+another literal when the new merged literal location is within the
+offset range of all of its uses.
+
+The relaxation mechanism will also attempt to optimize
+assembler-generated ``longcall'' sequences of
+@code{L32R}/@code{CALLX@var{n}} when the target is known to fit into a
+@code{CALL@var{n}} instruction encoding. The current optimization
+converts the sequence into @code{NOP}/@code{CALL@var{n}} and removes the
+literal referenced by the @code{L32R} instruction.
+
+@ifclear GENERIC
+@lowersections
+@end ifclear
+@end ifset
+
@ifclear SingleFormat
@node BFD
@chapter BFD