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[binutils-gdb/binutils-2_29-branch] PowerPC64 --plt-align
- From: Alan Modra <amodra at sourceware dot org>
- To: bfd-cvs at sourceware dot org
- Date: 10 Sep 2017 09:05:49 -0000
- Subject: [binutils-gdb/binutils-2_29-branch] PowerPC64 --plt-align
https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=38d47c2247aea860c41aa4bdddc4bed34e378731
commit 38d47c2247aea860c41aa4bdddc4bed34e378731
Author: Alan Modra <amodra@gmail.com>
Date: Sat Sep 9 21:55:22 2017 +0930
PowerPC64 --plt-align
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)
Diff:
---
bfd/ChangeLog | 5 +++++
bfd/elf64-ppc.c | 19 ++++++++++++++++---
ld/ChangeLog | 9 +++++++++
ld/emultempl/ppc64elf.em | 2 +-
ld/ld.texinfo | 10 ++++++----
ld/testsuite/ld-powerpc/elfv2so.d | 30 +++++++++++++++++-------------
ld/testsuite/ld-powerpc/powerpc.exp | 16 ++++++++--------
ld/testsuite/ld-powerpc/relbrlt.d | 2 +-
8 files changed, 63 insertions(+), 30 deletions(-)
diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index a78e819..708a4bf 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,8 @@
+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
diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c
index 4ff3f06..3f01ae6 100644
--- a/bfd/elf64-ppc.c
+++ b/bfd/elf64-ppc.c
@@ -10606,17 +10606,30 @@ plt_stub_size (struct ppc_link_hash_table *htab,
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));
diff --git a/ld/ChangeLog b/ld/ChangeLog
index e8ee459..f1acd5b 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,12 @@
+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:
diff --git a/ld/emultempl/ppc64elf.em b/ld/emultempl/ppc64elf.em
index 58cb798..cf75957 100644
--- a/ld/emultempl/ppc64elf.em
+++ b/ld/emultempl/ppc64elf.em
@@ -37,7 +37,7 @@ static struct ppc64_elf_params params = { NULL,
&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. */
diff --git a/ld/ld.texinfo b/ld/ld.texinfo
index 5d0b007..950c794 100644
--- a/ld/ld.texinfo
+++ b/ld/ld.texinfo
@@ -7572,10 +7572,12 @@ off this feature.
@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
diff --git a/ld/testsuite/ld-powerpc/elfv2so.d b/ld/testsuite/ld-powerpc/elfv2so.d
index f3962ac..a577b2a 100644
--- a/ld/testsuite/ld-powerpc/elfv2so.d
+++ b/ld/testsuite/ld-powerpc/elfv2so.d
@@ -7,53 +7,57 @@
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
diff --git a/ld/testsuite/ld-powerpc/powerpc.exp b/ld/testsuite/ld-powerpc/powerpc.exp
index 6249ccb..cfbc7b2 100644
--- a/ld/testsuite/ld-powerpc/powerpc.exp
+++ b/ld/testsuite/ld-powerpc/powerpc.exp
@@ -156,22 +156,22 @@ set ppcelftests {
}
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"}
@@ -179,17 +179,17 @@ set ppc64elftests {
{{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"}
@@ -210,7 +210,7 @@ set ppc64elftests {
"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}
diff --git a/ld/testsuite/ld-powerpc/relbrlt.d b/ld/testsuite/ld-powerpc/relbrlt.d
index a5f2437..a00b1ff 100644
--- a/ld/testsuite/ld-powerpc/relbrlt.d
+++ b/ld/testsuite/ld-powerpc/relbrlt.d
@@ -1,6 +1,6 @@
#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
.*