This changes the PowerPC64 --plt-align option to perform the usual
alignment of code as suggested by its name, as well as the previous
behaviour of padding so as to reduce boundary crossing. The old
behaviour is had by using a negative parameter.
The default is also changed to align plt stub code by default to 32
byte boundaries, the point being to get better bctr branch prediction
on power8 and power9 hardware.
bfd/
* elf64-ppp.c (plt_stub_pad): Handle positive and negative
plt_stub_align.
ld/
* ld.texinfo (--plt-align): Describe new behaviour of option.
* emultempl/ppc64elf.em (params): Default plt_stub_align to 5.
* testsuite/ld-powerpc/powerpc.exp: Pass --no-plt-align for
selected tests.
* testsuite/ld-powerpc/relbrlt.d: Pass --no-plt-align.
* testsuite/ld-powerpc/elfv2so.d: Adjust expected output.
(cherry picked from commit
2420fff633eff03ec1f85eba82a926cd0ecf4229)
(and commit
bab55c05 for part of elfv2so.d change)
+2017-09-10 Alan Modra <amodra@gmail.com>
+
+ * elf64-ppp.c (plt_stub_pad): Handle positive and negative
+ plt_stub_align.
+
2017-09-09 H.J. Lu <hongjiu.lu@intel.com>
PR binutils/22018
return size;
}
-/* If this stub would cross fewer 2**plt_stub_align boundaries if we align,
- then return the padding needed to do so. */
+/* Depending on the sign of plt_stub_align:
+ If positive, return the padding to align to a 2**plt_stub_align
+ boundary.
+ If negative, if this stub would cross fewer 2**plt_stub_align
+ boundaries if we align, then return the padding needed to do so. */
+
static inline unsigned int
plt_stub_pad (struct ppc_link_hash_table *htab,
struct ppc_stub_hash_entry *stub_entry,
bfd_vma plt_off)
{
- int stub_align = 1 << htab->params->plt_stub_align;
+ int stub_align;
unsigned stub_size = plt_stub_size (htab, stub_entry, plt_off);
bfd_vma stub_off = stub_entry->group->stub_sec->size;
+ if (htab->params->plt_stub_align >= 0)
+ {
+ stub_align = 1 << htab->params->plt_stub_align;
+ if ((stub_off & (stub_align - 1)) != 0)
+ return stub_align - (stub_off & (stub_align - 1));
+ return 0;
+ }
+
+ stub_align = 1 << -htab->params->plt_stub_align;
if (((stub_off + stub_size - 1) & -stub_align) - (stub_off & -stub_align)
> ((stub_size - 1) & -stub_align))
return stub_align - (stub_off & (stub_align - 1));
+2017-09-10 Alan Modra <amodra@gmail.com>
+
+ * ld.texinfo (--plt-align): Describe new behaviour of option.
+ * emultempl/ppc64elf.em (params): Default plt_stub_align to 5.
+ * testsuite/ld-powerpc/powerpc.exp: Pass --no-plt-align for
+ selected tests.
+ * testsuite/ld-powerpc/relbrlt.d: Pass --no-plt-align.
+ * testsuite/ld-powerpc/elfv2so.d: Adjust expected output.
+
2017-09-04 Nick Clifton <nickc@redhat.com>
Import from mainline:
&ppc_add_stub_section,
&ppc_layout_sections_again,
1, -1, 0,
- ${DEFAULT_PLT_STATIC_CHAIN-0}, -1, 0,
+ ${DEFAULT_PLT_STATIC_CHAIN-0}, -1, 5,
-1, 0, -1, -1, 0};
/* Fake input file for stubs. */
@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
Disassembly of section \.text:
-0+300 <.*\.plt_call\.f4>:
+.* <.*\.plt_call\.f4>:
.*: (f8 41 00 18|18 00 41 f8) std r2,24\(r1\)
.*: (e9 82 80 38|38 80 82 e9) ld r12,-32712\(r2\)
.*: (7d 89 03 a6|a6 03 89 7d) mtctr r12
.*: (4e 80 04 20|20 04 80 4e) bctr
+ \.\.\.
-0+310 <.*\.plt_call\.f3>:
+.* <.*\.plt_call\.f3>:
.*: (f8 41 00 18|18 00 41 f8) std r2,24\(r1\)
.*: (e9 82 80 28|28 80 82 e9) ld r12,-32728\(r2\)
.*: (7d 89 03 a6|a6 03 89 7d) mtctr r12
.*: (4e 80 04 20|20 04 80 4e) bctr
+ \.\.\.
-0+320 <.*\.plt_call\.f2>:
+.* <.*\.plt_call\.f2>:
.*: (f8 41 00 18|18 00 41 f8) std r2,24\(r1\)
.*: (e9 82 80 30|30 80 82 e9) ld r12,-32720\(r2\)
.*: (7d 89 03 a6|a6 03 89 7d) mtctr r12
.*: (4e 80 04 20|20 04 80 4e) bctr
+ \.\.\.
-0+330 <.*\.plt_call\.f1>:
+.* <.*\.plt_call\.f1>:
.*: (f8 41 00 18|18 00 41 f8) std r2,24\(r1\)
.*: (e9 82 80 40|40 80 82 e9) ld r12,-32704\(r2\)
.*: (7d 89 03 a6|a6 03 89 7d) mtctr r12
.*: (4e 80 04 20|20 04 80 4e) bctr
+ \.\.\.
-0+340 <f1>:
+.* <f1>:
.*: (3c 4c 00 02|02 00 4c 3c) addis r2,r12,2
-.*: (38 42 82 c0|c0 82 42 38) addi r2,r2,-32064
+.*: (38 42 .. ..|.. .. 42 38) addi r2,r2,.*
.*: (7c 08 02 a6|a6 02 08 7c) mflr r0
.*: (f8 21 ff e1|e1 ff 21 f8) stdu r1,-32\(r1\)
.*: (f8 01 00 30|30 00 01 f8) std r0,48\(r1\)
-.*: (4b ff ff dd|dd ff ff 4b) bl .*\.plt_call\.f1>
+.*: (4b ff ff cd|cd ff ff 4b) bl .*\.plt_call\.f1>
.*: (e8 62 80 08|08 80 62 e8) ld r3,-32760\(r2\)
-.*: (4b ff ff c5|c5 ff ff 4b) bl .*\.plt_call\.f2>
+.*: (4b ff ff a5|a5 ff ff 4b) bl .*\.plt_call\.f2>
.*: (e8 41 00 18|18 00 41 e8) ld r2,24\(r1\)
.*: (e8 62 80 10|10 80 62 e8) ld r3,-32752\(r2\)
-.*: (4b ff ff a9|a9 ff ff 4b) bl .*\.plt_call\.f3>
+.*: (4b ff ff 79|79 ff ff 4b) bl .*\.plt_call\.f3>
.*: (e8 41 00 18|18 00 41 e8) ld r2,24\(r1\)
-.*: (4b ff ff 91|91 ff ff 4b) bl .*\.plt_call\.f4>
+.*: (4b ff ff 51|51 ff ff 4b) bl .*\.plt_call\.f4>
.*: (e8 41 00 18|18 00 41 e8) ld r2,24\(r1\)
.*: (e8 01 00 30|30 00 01 e8) ld r0,48\(r1\)
.*: (38 21 00 20|20 00 21 38) addi r1,r1,32
.*: (7c 08 03 a6|a6 03 08 7c) mtlr r0
.*: (4e 80 00 20|20 00 80 4e) blr
-.*: (00 00 00 00|80 02 01 00) .*
-.*: (00 01 02 80|00 00 00 00) .*
+.*
+.*
-0+390 <__glink_PLTresolve>:
+.* <__glink_PLTresolve>:
.*: (7c 08 02 a6|a6 02 08 7c) mflr r0
.*: (42 9f 00 05|05 00 9f 42) bcl .*
.*: (7d 68 02 a6|a6 02 68 7d) mflr r11
}
set ppc64elftests {
- {"TLS static exec" "-melf64ppc" "" "-a64" {tls.s tlslib.s}
+ {"TLS static exec" "-melf64ppc --no-plt-align" "" "-a64" {tls.s tlslib.s}
{{objdump -dr tls.d} {objdump -sj.got tls.g} {objdump -sj.tdata tls.t}}
"tls"}
{"TLS helper shared library" "-shared -melf64ppc tmpdir/tlslib.o" "" "" {}
{} "libtlslib.so"}
{"TLS helper old shared lib" "-shared -melf64ppc" "" "-a64" {oldtlslib.s}
{} "liboldlib.so"}
- {"TLS dynamic exec" "-melf64ppc --no-ld-generated-unwind-info tmpdir/tls.o tmpdir/libtlslib.so" "" "" {}
+ {"TLS dynamic exec" "-melf64ppc --no-plt-align --no-ld-generated-unwind-info tmpdir/tls.o tmpdir/libtlslib.so" "" "" {}
{{readelf -WSsrl tlsexe.r} {objdump -dr tlsexe.d}
{objdump -sj.got tlsexe.g} {objdump -sj.tdata tlsexe.t}}
"tlsexe"}
- {"TLS dynamic old" "-melf64ppc --no-ld-generated-unwind-info tmpdir/tls.o tmpdir/liboldlib.so" "" "" {}
+ {"TLS dynamic old" "-melf64ppc --no-plt-align --no-ld-generated-unwind-info tmpdir/tls.o tmpdir/liboldlib.so" "" "" {}
{{readelf -WSsrl tlsexe.r} {objdump -dr tlsexe.d}
{objdump -sj.got tlsexe.g} {objdump -sj.tdata tlsexe.t}}
"tlsexeold"}
- {"TLS shared" "-shared -melf64ppc --no-ld-generated-unwind-info tmpdir/tls.o" "" "" {}
+ {"TLS shared" "-shared -melf64ppc --no-plt-align --no-ld-generated-unwind-info tmpdir/tls.o" "" "" {}
{{readelf -WSsrl tlsso.r} {objdump -dr tlsso.d}
{objdump -sj.got tlsso.g} {objdump -sj.tdata tlsso.t}}
"tls.so"}
{{objdump -dr tlstoc.d} {objdump -sj.got tlstoc.g}
{objdump -sj.tdata tlstoc.t}}
"tlstoc"}
- {"TLSTOC dynamic exec" "-melf64ppc --no-ld-generated-unwind-info tmpdir/tlstoc.o tmpdir/libtlslib.so" ""
+ {"TLSTOC dynamic exec" "-melf64ppc --no-plt-align --no-ld-generated-unwind-info tmpdir/tlstoc.o tmpdir/libtlslib.so" ""
"" {}
{{readelf -WSsrl tlsexetoc.r} {objdump -dr tlsexetoc.d}
{objdump -sj.got tlsexetoc.g} {objdump -sj.tdata tlsexetoc.t}}
"tlsexetoc"}
- {"TLSTOC dynamic old" "-melf64ppc --no-ld-generated-unwind-info tmpdir/tlstoc.o tmpdir/liboldlib.so" ""
+ {"TLSTOC dynamic old" "-melf64ppc --no-plt-align --no-ld-generated-unwind-info tmpdir/tlstoc.o tmpdir/liboldlib.so" ""
"" {}
{{readelf -WSsrl tlsexetoc.r} {objdump -dr tlsexetoc.d}
{objdump -sj.got tlsexetoc.g} {objdump -sj.tdata tlsexetoc.t}}
"tlsexetocold"}
- {"TLSTOC shared" "-shared -melf64ppc --no-ld-generated-unwind-info tmpdir/tlstoc.o" "" "" {}
+ {"TLSTOC shared" "-shared -melf64ppc --no-plt-align --no-ld-generated-unwind-info tmpdir/tlstoc.o" "" "" {}
{{readelf -WSsrl tlstocso.r} {objdump -dr tlstocso.d}
{objdump -sj.got tlstocso.g} {objdump -sj.tdata tlstocso.t}}
"tlstoc.so"}
"tlsopt4"}
{"TLS DLL" "-shared -melf64ppc --version-script tlsdll.ver" "" "-a64" {tlsdll.s}
{} "tlsdll.so"}
- {"TLS opt 5" "-melf64ppc -shared --gc-sections --no-plt-localentry tmpdir/tlsdll.so" "" "-a64" {tlsopt5.s}
+ {"TLS opt 5" "-melf64ppc --no-plt-align -shared --gc-sections --no-plt-localentry tmpdir/tlsdll.so" "" "-a64" {tlsopt5.s}
{{objdump -dr tlsopt5.d} {readelf -wf tlsopt5.wf}}
"tlsopt5"}
{"sym@tocbase" "-shared -melf64ppc" "" "-a64" {symtocbase-1.s symtocbase-2.s}
#source: relbrlt.s
#as: -a64
-#ld: -melf64ppc --no-ld-generated-unwind-info --emit-relocs
+#ld: -melf64ppc --no-plt-align --no-ld-generated-unwind-info --emit-relocs
#objdump: -Dr
.*