Document powerpc64 ld options

	* ld.texi (PowerPC64 ELF64): Document --no-inline-optimize,
	--power10-stubs and --no-power10-stubs.

(cherry picked from commit d882c9889312591a8bfdbc1740938780cd4032bd)

diff --git a/ld/ChangeLog b/ld/ChangeLog
index 3b4e0dfc39d89825a95a6a17fb2309e61210d6d0..fd9e97de78aabd7e2002bd901ff53dbdb5738e2a 100644 (file)
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,8 @@
+2020-07-10  Alan Modra  <amodra@gmail.com>
+
+       * ld.texi (PowerPC64 ELF64): Document --no-inline-optimize,
+       --power10-stubs and --no-power10-stubs.
+
 2020-07-10  Alan Modra  <amodra@gmail.com>
 
        * emultempl/ppc64elf.em (params): Init new field.

diff --git a/ld/ld.texi b/ld/ld.texi
index 40b042de9b958690bf806e578b4e7f1f0a171687..165a3d935e16e9c7497bdf51c1f50ae39bdc2e76 100644 (file)
--- a/ld/ld.texi
+++ b/ld/ld.texi
@@ -7823,6 +7823,16 @@ reliably for compiler generated code, but may be incorrect if assembly
 code is used to insert TOC entries.  Use this option to disable the
 optimization.
 
+@cindex PowerPC64 inline PLT call optimization
+@kindex --no-inline-optimize
+@item --no-inline-optimize
+PowerPC64 @command{ld} normally replaces inline PLT call sequences
+marked with @code{R_PPC64_PLTSEQ}, @code{R_PPC64_PLTCALL},
+@code{R_PPC64_PLT16_HA} and @code{R_PPC64_PLT16_LO_DS} relocations by
+a number of @code{nop}s and a direct call when the function is defined
+locally and can't be overridden by some other definition.  This option
+disables that optimization.
+
 @cindex PowerPC64 multi-TOC
 @kindex --no-multi-toc
 @item --no-multi-toc
@@ -7904,6 +7914,23 @@ including system libraries, can cause a function that was localentry:0
 to become localentry:8.  This will result in a dynamic loader
 complaint and failure to run.  The option is experimental, use with
 care.  @option{--no-plt-localentry} is the default.
+
+@cindex PowerPC64 Power10 stubs
+@kindex --power10-stubs
+@kindex --no-power10-stubs
+@item --power10-stubs
+@itemx --no-power10-stubs
+When PowerPC64 @command{ld} links input object files containing
+relocations used on power10 prefixed instructions it normally creates
+linkage stubs (PLT call and long branch) using power10 instructions.
+In particular for @code{@@notoc} PLT calls where @code{r2} is not
+known the power10 stubs are smaller and faster, so are preferred for
+power10.  @option{--power10-stubs} and @option{--no-power10-stubs}
+allow you to override the linker's selection of stub instructions.
+For example, when linking a shared library that contains cpu-optimized
+versions of functions for both power9 and power10, you might use
+@option{--no-power10-stubs} so that power9 code making calls doesn't
+attempt to execute power10 instructions.
 @end table
 
 @ifclear GENERIC