x86-64: Test protected function pointers

On x86-64, function pointers in executable for external funtions may be
resolved to their PLT entries in executable.  If it happens, function
pointers of protected funtions in shared libraries must be resolved to
the PLT entries in executable, not addresses of protected funtions in
shared libraries.

	PR ld/27973
	* testsuite/ld-x86-64/x86-64.exp: Run protected function tests.
	* testsuite/ld-x86-64/protected-func-1.h: New file.
	* testsuite/ld-x86-64/protected-func-1a.s: Likewise.
	* testsuite/ld-x86-64/protected-func-1b.c: Likewise.

5 files changed, 122 insertions, 0 deletions

diff --git a/ld/ChangeLog b/ld/ChangeLog
index 3d3cbed..2b46bb9 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,11 @@
+2021-06-17  H.J. Lu  <hongjiu.lu@intel.com>
+
+	PR ld/27973
+	* testsuite/ld-x86-64/x86-64.exp: Run protected function tests.
+	* testsuite/ld-x86-64/protected-func-1.h: New file.
+	* testsuite/ld-x86-64/protected-func-1a.s: Likewise.
+	* testsuite/ld-x86-64/protected-func-1b.c: Likewise.
+
 2021-06-17  Fangrui Song  <maskray@google.com>
 
 	* ldlex.h (enum option_values): Add OPTION_NO_PIE.
diff --git a/ld/testsuite/ld-x86-64/protected-func-1.h b/ld/testsuite/ld-x86-64/protected-func-1.h
new file mode 100644
index 0000000..b5ff4e8
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/protected-func-1.h
@@ -0,0 +1,6 @@
+extern int protected_func_1a (void);
+extern int protected_func_1b (void);
+
+typedef int (*protected_func_type) (void);
+extern protected_func_type protected_func_1a_p (void);
+extern protected_func_type protected_func_1b_p (void);
diff --git a/ld/testsuite/ld-x86-64/protected-func-1a.s b/ld/testsuite/ld-x86-64/protected-func-1a.s
new file mode 100644
index 0000000..eb2ed91
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/protected-func-1a.s
@@ -0,0 +1,48 @@
+	.text
+	.p2align 4
+	.protected	protected_func_1a
+	.globl	protected_func_1a
+	.type	protected_func_1a, @function
+protected_func_1a:
+.LFB0:
+	.cfi_startproc
+	movl	$1, %eax
+	ret
+	.cfi_endproc
+.LFE0:
+	.size	protected_func_1a, .-protected_func_1a
+	.p2align 4
+	.protected	protected_func_1b
+	.globl	protected_func_1b
+	.type	protected_func_1b, @function
+protected_func_1b:
+.LFB1:
+	.cfi_startproc
+	movl	$2, %eax
+	ret
+	.cfi_endproc
+.LFE1:
+	.size	protected_func_1b, .-protected_func_1b
+	.p2align 4
+	.globl	protected_func_1a_p
+	.type	protected_func_1a_p, @function
+protected_func_1a_p:
+.LFB2:
+	.cfi_startproc
+	movq	protected_func_1a@GOTPCREL(%rip), %rax
+	ret
+	.cfi_endproc
+.LFE2:
+	.size	protected_func_1a_p, .-protected_func_1a_p
+	.p2align 4
+	.globl	protected_func_1b_p
+	.type	protected_func_1b_p, @function
+protected_func_1b_p:
+.LFB3:
+	.cfi_startproc
+	movq	protected_func_1b@GOTPCREL(%rip), %rax
+	ret
+	.cfi_endproc
+.LFE3:
+	.size	protected_func_1b_p, .-protected_func_1b_p
+	.section	.note.GNU-stack,"",@progbits
diff --git a/ld/testsuite/ld-x86-64/protected-func-1b.c b/ld/testsuite/ld-x86-64/protected-func-1b.c
new file mode 100644
index 0000000..a9d728a
--- /dev/null
+++ b/ld/testsuite/ld-x86-64/protected-func-1b.c
@@ -0,0 +1,35 @@
+#include <stdio.h>
+
+#include "protected-func-1.h"
+
+int
+protected_func_1b (void)
+{
+  return 3;
+}
+
+int
+main (void)
+{
+  int res = 0;
+
+  /* Check if we get the same address for the protected function symbol.  */
+  if (protected_func_1a != protected_func_1a_p ())
+    {
+      puts ("'protected_func_1a' in main and shared library doesn't have same address");
+      res = 1;
+    }
+
+  /* Check if we get the different addresses for the protected function
+     symbol.  */
+  if (protected_func_1b == protected_func_1b_p ())
+    {
+      puts ("'protected_func_1b' in main and shared library has same address");
+      res = 1;
+    }
+
+  if (!res)
+    puts ("PASS");
+
+  return res;
+}
diff --git a/ld/testsuite/ld-x86-64/x86-64.exp b/ld/testsuite/ld-x86-64/x86-64.exp
index 8071666..5dc9a1c 100644
--- a/ld/testsuite/ld-x86-64/x86-64.exp
+++ b/ld/testsuite/ld-x86-64/x86-64.exp
@@ -1321,6 +1321,14 @@ if { [isnative] && [check_compiler_available] } {
 	     {readelf -rW pr22842b.rd}} \
 	    "pr22842" \
 	] \
+	[list \
+	    "Build libprotected-func-1.so" \
+	    "-shared" \
+	    "-fPIC -Wa,-mx86-used-note=yes" \
+	    { protected-func-1a.s } \
+	    {} \
+	    "libprotected-func-1.so" \
+	] \
     ]
 
     if  {[istarget "x86_64-*-linux*-gnux32"]} {
@@ -1730,6 +1738,23 @@ if { [isnative] && [check_compiler_available] } {
 	    "pr23997" \
 	    "pass.out" \
 	] \
+	[list \
+	    "Run protected-func-1 without PIE" \
+	    "-Wl,--no-as-needed tmpdir/libprotected-func-1.so" \
+	    "-Wa,-mx86-used-note=yes" \
+	    { protected-func-1b.c } \
+	    "protected-func-1a" \
+	    "pass.out" \
+	] \
+	[list \
+	    "Run protected-func-1 with PIE" \
+	    "-Wl,--no-as-needed -pie tmpdir/libprotected-func-1.so" \
+	    "-Wa,-mx86-used-note=yes" \
+	    { protected-func-1b.c } \
+	    "protected-func-1b" \
+	    "pass.out" \
+	    "-fPIE" \
+	] \
     ]
 
     # Run-time tests which require working ifunc attribute support.