Keep .plt section and DT_PLTGOT for prelink

Since the .plt section and DT_PLTGOT are used by prelink to undo
prelinking for dynamic relocations, we must keep them even if there is
no PLT relocation.  This patch reverted commit a3747075a.

bfd/

	* elf32-i386.c (elf_i386_allocate_dynrelocs): Always allocate
	space for the first .plt entry.
	(elf_i386_size_dynamic_sections): Always add DT_PLTGOT for .plt
	section.  Add DT_PLTRELSZ, DT_PLTREL and DT_JMPREL only if
	there are PLT relocations.
	* elf64-x86-64.c (elf_x86_64_allocate_dynrelocs): Always
	allocate space for the first .plt entry.
	(elf_x86_64_size_dynamic_sections): Always add DT_PLTGOT for
	.plt section.  Add DT_PLTRELSZ, DT_PLTREL and DT_JMPREL only if
	there are PLT relocations.

ld/testsuite/

	* ld-i386/i386.exp: Run pltgot-2 for Linux targets.
	* ld-x86-64/x86-64.exp: Likewise.
	* ld-i386/pltgot-1.d: Updated.
	* ld-x86-64/pltgot-1.d: Likewise.
	* ld-i386/pltgot-2.d: New file.
	* ld-x86-64/pltgot-2.d: Likewise.

7 files changed, 35 insertions, 4 deletions

diff --git a/ld/testsuite/ChangeLog b/ld/testsuite/ChangeLog
index 812549c..2031bc8 100644
--- a/ld/testsuite/ChangeLog
+++ b/ld/testsuite/ChangeLog
@@ -1,3 +1,12 @@
+2015-06-24  H.J. Lu  <hongjiu.lu@intel.com>
+
+	* ld-i386/i386.exp: Run pltgot-2 for Linux targets.
+	* ld-x86-64/x86-64.exp: Likewise.
+	* ld-i386/pltgot-1.d: Updated.
+	* ld-x86-64/pltgot-1.d: Likewise.
+	* ld-i386/pltgot-2.d: New file.
+	* ld-x86-64/pltgot-2.d: Likewise.
+
 2015-06-23  Jiong Wang  <jiong.wang@arm.com>
 
 	* ld-aarch64/dt_textrel.s: New testcase.
diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp
index a26cffd..61f9599 100644
--- a/ld/testsuite/ld-i386/i386.exp
+++ b/ld/testsuite/ld-i386/i386.exp
@@ -525,3 +525,4 @@ if { !([istarget "i?86-*-linux*"]
 
 # Linux only tests
 run_dump_test "pltgot-1"
+run_dump_test "pltgot-2"
diff --git a/ld/testsuite/ld-i386/pltgot-1.d b/ld/testsuite/ld-i386/pltgot-1.d
index 6629635..165ae33 100644
--- a/ld/testsuite/ld-i386/pltgot-1.d
+++ b/ld/testsuite/ld-i386/pltgot-1.d
@@ -2,7 +2,8 @@
 #readelf: -S --wide
 #as: --32
 
-#failif
 #...
- +\[ [0-9]+\] \.plt +PROGBITS +.*
+ +\[ *[0-9]+\] \.plt +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +0+10 +.*
 #...
+ +\[ *[0-9]+\] \.got\.plt +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +0+c +.*
+#pass
diff --git a/ld/testsuite/ld-i386/pltgot-2.d b/ld/testsuite/ld-i386/pltgot-2.d
new file mode 100644
index 0000000..3b87898
--- /dev/null
+++ b/ld/testsuite/ld-i386/pltgot-2.d
@@ -0,0 +1,9 @@
+#source: pltgot-1.s
+#ld: -shared -melf_i386
+#readelf: -d --wide
+#as: --32
+
+#failif
+#...
+ +0x[0-9a-f]+ +\(PLTREL.*
+#...
diff --git a/ld/testsuite/ld-x86-64/pltgot-1.d b/ld/testsuite/ld-x86-64/pltgot-1.d
index 9a6c2fd6..17d4f43 100644
--- a/ld/testsuite/ld-x86-64/pltgot-1.d
+++ b/ld/testsuite/ld-x86-64/pltgot-1.d
@@ -2,7 +2,8 @@
 #readelf: -S --wide
 #as: --64
 
-#failif
 #...
- +\[ [0-9]+\] \.plt +PROGBITS +.*
+ +\[ *[0-9]+\] \.plt +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +0+10 +.*
 #...
+ +\[ *[0-9]+\] \.got\.plt +PROGBITS +[0-9a-f]+ +[0-9a-f]+ +0+18 +.*
+#pass
diff --git a/ld/testsuite/ld-x86-64/pltgot-2.d b/ld/testsuite/ld-x86-64/pltgot-2.d
new file mode 100644
index 0000000..086d6dd
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/pltgot-2.d
@@ -0,0 +1,9 @@
+#source: pltgot-1.s
+#ld: -shared -melf_x86_64
+#readelf: -d --wide
+#as: --64
+
+#failif
+#...
+ +0x[0-9a-f]+ +\(PLTREL.*
+#...
diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp
index 8281dc4..3669446 100644
--- a/ld/testsuite/ld-x86-64/x86-64.exp
+++ b/ld/testsuite/ld-x86-64/x86-64.exp
@@ -574,3 +574,4 @@ if { ![istarget "x86_64-*-linux*"]} {
 # Linux only tests
 run_dump_test "pr17618"
 run_dump_test "pltgot-1"
+run_dump_test "pltgot-2"