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[committed, PATCH] Handle local IFUNC symbols in shared object

From: "H.J. Lu" <hongjiu dot lu at intel dot com>
To: binutils at sourceware dot org
Date: Tue, 8 Mar 2016 09:44:10 -0800
Subject: [committed, PATCH] Handle local IFUNC symbols in shared object
Authentication-results: sourceware.org; auth=none
Reply-to: "H.J. Lu" <hjl dot tools at gmail dot com>
Increment PLT reference count for locally defined local IFUNC symbols
in shared object since STT_GNU_IFUNC symbol must go through PLT even
if it is locally defined and undefined symbol may turn out to be a
STT_GNU_IFUNC symbol later.

bfd/

	PR ld/19784
	* elf32-i386.c (elf_i386_check_relocs): Increment PLT reference
	count for locally defined local IFUNC symbols in shared object.
	* elf64-x86-64.c (elf_x86_64_check_relocs): Likewise.

ld/

	PR ld/19784
	* testsuite/ld-i386/i386.exp: Remove pr19636-2e-nacl test.
	* testsuite/ld-i386/pr19636-2e-nacl.d: Moved to ...
	* testsuite/ld-i386/pr19636-2e.d: Here.  Remove notarget.
	* testsuite/ld-ifunc/ifunc.exp: Run PR ld/19784 tests.
	* testsuite/ld-ifunc/pass.out: New file.
	* testsuite/ld-ifunc/pr19784a.c: Likewise.
	* testsuite/ld-ifunc/pr19784b.c: Likewise.
	* testsuite/ld-ifunc/pr19784c.c: Likewise.
---
 bfd/elf32-i386.c                       | 10 ++++++++-
 bfd/elf64-x86-64.c                     | 10 ++++++++-
 ld/testsuite/ld-i386/i386.exp          |  1 -
 ld/testsuite/ld-i386/pr19636-2e-nacl.d | 21 ------------------
 ld/testsuite/ld-i386/pr19636-2e.d      |  5 ++++-
 ld/testsuite/ld-ifunc/ifunc.exp        | 40 ++++++++++++++++++++++++++++++++++
 ld/testsuite/ld-ifunc/pass.out         |  1 +
 ld/testsuite/ld-ifunc/pr19784a.c       |  6 +++++
 ld/testsuite/ld-ifunc/pr19784b.c       | 11 ++++++++++
 ld/testsuite/ld-ifunc/pr19784c.c       | 11 ++++++++++
 10 files changed, 91 insertions(+), 25 deletions(-)
 delete mode 100644 ld/testsuite/ld-i386/pr19636-2e-nacl.d
 create mode 100644 ld/testsuite/ld-ifunc/pass.out
 create mode 100644 ld/testsuite/ld-ifunc/pr19784a.c
 create mode 100644 ld/testsuite/ld-ifunc/pr19784b.c
 create mode 100644 ld/testsuite/ld-ifunc/pr19784c.c

diff --git a/bfd/elf32-i386.c b/bfd/elf32-i386.c
index ab3945d..ac3c2f4 100644
--- a/bfd/elf32-i386.c
+++ b/bfd/elf32-i386.c
@@ -1808,7 +1808,15 @@ elf_i386_check_relocs (bfd *abfd,
 	  if (eh != NULL && (sec->flags & SEC_CODE) != 0)
 	    eh->has_non_got_reloc = 1;
 do_relocation:
-	  if (h != NULL && bfd_link_executable (info))
+	  /* STT_GNU_IFUNC symbol must go through PLT even if it is
+	     locally defined and undefined symbol may turn out to be
+	     a STT_GNU_IFUNC symbol later.  */
+	  if (h != NULL
+	      && (bfd_link_executable (info)
+		  || ((h->type == STT_GNU_IFUNC
+		       || h->root.type == bfd_link_hash_undefweak
+		       || h->root.type == bfd_link_hash_undefined)
+		      && SYMBOLIC_BIND (info, h))))
 	    {
 	      /* If this reloc is in a read-only section, we might
 		 need a copy reloc.  We can't check reliably at this
diff --git a/bfd/elf64-x86-64.c b/bfd/elf64-x86-64.c
index c696850..380376d 100644
--- a/bfd/elf64-x86-64.c
+++ b/bfd/elf64-x86-64.c
@@ -1999,7 +1999,15 @@ elf_x86_64_check_relocs (bfd *abfd, struct bfd_link_info *info,
 pointer:
 	  if (eh != NULL && (sec->flags & SEC_CODE) != 0)
 	    eh->has_non_got_reloc = 1;
-	  if (h != NULL && bfd_link_executable (info))
+	  /* STT_GNU_IFUNC symbol must go through PLT even if it is
+	     locally defined and undefined symbol may turn out to be
+	     a STT_GNU_IFUNC symbol later.  */
+	  if (h != NULL
+	      && (bfd_link_executable (info)
+		  || ((h->type == STT_GNU_IFUNC
+		       || h->root.type == bfd_link_hash_undefweak
+		       || h->root.type == bfd_link_hash_undefined)
+		      && SYMBOLIC_BIND (info, h))))
 	    {
 	      /* If this reloc is in a read-only section, we might
 		 need a copy reloc.  We can't check reliably at this
diff --git a/ld/testsuite/ld-i386/i386.exp b/ld/testsuite/ld-i386/i386.exp
index 5b9d790..a032ca7 100644
--- a/ld/testsuite/ld-i386/i386.exp
+++ b/ld/testsuite/ld-i386/i386.exp
@@ -337,7 +337,6 @@ run_dump_test "pr19636-2c-nacl"
 run_dump_test "pr19636-2d"
 run_dump_test "pr19636-2d-nacl"
 run_dump_test "pr19636-2e"
-run_dump_test "pr19636-2e-nacl"
 run_dump_test "pr19636-3a"
 run_dump_test "pr19636-3b"
 run_dump_test "pr19636-3c"
diff --git a/ld/testsuite/ld-i386/pr19636-2e-nacl.d b/ld/testsuite/ld-i386/pr19636-2e-nacl.d
deleted file mode 100644
index f791128..0000000
--- a/ld/testsuite/ld-i386/pr19636-2e-nacl.d
+++ /dev/null
@@ -1,21 +0,0 @@
-#source: pr19636-2.s
-#as: --32 -mrelax-relocations=no
-#ld: -shared -Bsymbolic -m elf_i386
-#readelf : -r --wide --dyn-syms
-#target: i?86-*-nacl* x86_64-*-nacl*
-
-Relocation section '\.rel\.dyn' at offset [0x0-9a-f]+ contains 3 entries:
- +Offset +Info +Type +Sym. Value +Symbol's Name
-[0-9a-f]+ +[0-9a-f]+ +R_386_32 +0+ +func
-[0-9a-f]+ +[0-9a-f]+ +R_386_PC32 +0+ +func
-[0-9a-f]+ +[0-9a-f]+ +R_386_GLOB_DAT +0+ +func
-
-Relocation section '\.rel\.plt' at offset [0x0-9a-f]+ contains 1 entries:
- +Offset +Info +Type +Sym. Value +Symbol's Name
-[0-9a-f]+ +[0-9a-f]+ +R_386_JUMP_SLOT +0+ +func
-
-Symbol table '\.dynsym' contains [0-9]+ entries:
- +Num: +Value +Size Type +Bind +Vis +Ndx Name
-#...
- +[0-9]+: +[a-f0-9]+ +0 +NOTYPE +WEAK +DEFAULT +UND +func
-#pass
diff --git a/ld/testsuite/ld-i386/pr19636-2e.d b/ld/testsuite/ld-i386/pr19636-2e.d
index 148e306..c985242 100644
--- a/ld/testsuite/ld-i386/pr19636-2e.d
+++ b/ld/testsuite/ld-i386/pr19636-2e.d
@@ -2,7 +2,6 @@
 #as: --32 -mrelax-relocations=no
 #ld: -shared -Bsymbolic -m elf_i386
 #readelf : -r --wide --dyn-syms
-#notarget: i?86-*-nacl* x86_64-*-nacl*
 
 Relocation section '\.rel\.dyn' at offset [0x0-9a-f]+ contains 3 entries:
  +Offset +Info +Type +Sym. Value +Symbol's Name
@@ -10,6 +9,10 @@ Relocation section '\.rel\.dyn' at offset [0x0-9a-f]+ contains 3 entries:
 [0-9a-f]+ +[0-9a-f]+ +R_386_PC32 +0+ +func
 [0-9a-f]+ +[0-9a-f]+ +R_386_GLOB_DAT +0+ +func
 
+Relocation section '\.rel\.plt' at offset [0x0-9a-f]+ contains 1 entries:
+ +Offset +Info +Type +Sym. Value +Symbol's Name
+[0-9a-f]+ +[0-9a-f]+ +R_386_JUMP_SLOT +0+ +func
+
 Symbol table '\.dynsym' contains [0-9]+ entries:
  +Num: +Value +Size Type +Bind +Vis +Ndx Name
 #...
diff --git a/ld/testsuite/ld-ifunc/ifunc.exp b/ld/testsuite/ld-ifunc/ifunc.exp
index 96627e7..e860f36 100644
--- a/ld/testsuite/ld-ifunc/ifunc.exp
+++ b/ld/testsuite/ld-ifunc/ifunc.exp
@@ -505,6 +505,30 @@ run_cc_link_tests [list \
 	{} \
 	"libpr18841c.so" \
     ] \
+    [list \
+	"Build libpr19784a.so" \
+	"-shared -Wl,-Bsymbolic-functions" \
+	"-fPIC -O2 -g" \
+	{ pr19784b.c pr19784c.c } \
+	{} \
+	"libpr19784a.so" \
+    ] \
+    [list \
+	"Build libpr19784b.so" \
+	"-shared -Wl,-Bsymbolic-functions" \
+	"-fPIC -O2 -g" \
+	{ pr19784c.c pr19784b.c } \
+	{} \
+	"libpr19784b.so" \
+    ] \
+    [list \
+	"Build pr19784a.o" \
+	"" \
+	"" \
+	{ pr19784a.c } \
+	"" \
+	"" \
+    ] \
 ]
 
 run_ld_link_exec_tests [] [list \
@@ -532,4 +556,20 @@ run_ld_link_exec_tests [] [list \
 	"pr18841c" \
 	"pr18841.out" \
     ] \
+    [list \
+	"Run pr19784a" \
+	"tmpdir/pr19784a.o tmpdir/libpr19784a.so" \
+	"" \
+	{ dummy.c } \
+	"pr19784a" \
+	"pass.out" \
+    ] \
+    [list \
+	"Run pr19784b" \
+	"--as-needed tmpdir/pr19784a.o tmpdir/libpr19784b.so" \
+	"" \
+	{ dummy.c } \
+	"pr19784b" \
+	"pass.out" \
+    ] \
 ]
diff --git a/ld/testsuite/ld-ifunc/pass.out b/ld/testsuite/ld-ifunc/pass.out
new file mode 100644
index 0000000..7ef22e9
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/pass.out
@@ -0,0 +1 @@
+PASS
diff --git a/ld/testsuite/ld-ifunc/pr19784a.c b/ld/testsuite/ld-ifunc/pr19784a.c
new file mode 100644
index 0000000..c922cb9
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/pr19784a.c
@@ -0,0 +1,6 @@
+void bar(void);
+int main(void)
+{
+  bar();
+  return 0;
+}
diff --git a/ld/testsuite/ld-ifunc/pr19784b.c b/ld/testsuite/ld-ifunc/pr19784b.c
new file mode 100644
index 0000000..8ea7ce2
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/pr19784b.c
@@ -0,0 +1,11 @@
+int foo (int x) __attribute__ ((ifunc ("resolve_foo")));
+
+static int foo_impl(int x)
+{
+  return x;
+}
+
+void *resolve_foo (void)
+{
+  return (void *) foo_impl;
+}
diff --git a/ld/testsuite/ld-ifunc/pr19784c.c b/ld/testsuite/ld-ifunc/pr19784c.c
new file mode 100644
index 0000000..117dfec
--- /dev/null
+++ b/ld/testsuite/ld-ifunc/pr19784c.c
@@ -0,0 +1,11 @@
+#include <stdio.h>
+
+extern void abort (void);
+extern int foo (int) __attribute__ ((visibility("hidden")));
+
+int bar()
+{
+  if (foo (5) != 5)
+    abort ();
+  printf("PASS\n");
+}
-- 
2.5.0
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