[GCC, AARCH64] Add GNU note section with BTI and PAC.

This patch adds the GNU NOTE section to the BTI and/or PAC
enabled objects for linux targets.

The patches for needed for these in binutils are already approved
and committed.
https://sourceware.org/ml/binutils/2019-03/msg00072.html

*** gcc/ChangeLog ***

2018-04-23  Sudakshina Das  <sudi.das@arm.com>

	* config/aarch64/aarch64-linux.h (TARGET_ASM_FILE_END): Define for
	AArch64.
	(aarch64_file_end_indicate_exec_stack): Add gnu note section.

gcc/testsuite/ChangeLog:

2018-04-23  Sudakshina Das  <sudi.das@arm.com>

	* gcc.target/aarch64/bti-1.c: Add scan directive for gnu note section
	for linux targets.
	* gcc.target/aarch64/va_arg_1.c: Update scan directive to not clash
	with GNU note section.

From-SVN: r270515

6 files changed, 68 insertions, 2 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5ea2fa0..2c1cc37 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2018-04-23  Sudakshina Das  <sudi.das@arm.com>
+
+	* config/aarch64/aarch64-linux.h (TARGET_ASM_FILE_END): Define for
+	AArch64.
+	(aarch64_file_end_indicate_exec_stack): Add gnu note section.
+
+
 2019-04-23  Roman Zhuykov  <zhroma@ispras.ru>
 
 	PR rtl-optimization/87979
diff --git a/gcc/config/aarch64/aarch64-linux.h b/gcc/config/aarch64/aarch64-linux.h
index 9d0292d..5e8b34d 100644
--- a/gcc/config/aarch64/aarch64-linux.h
+++ b/gcc/config/aarch64/aarch64-linux.h
@@ -83,7 +83,7 @@
 
 #define GNU_USER_TARGET_D_CRITSEC_SIZE 48
 
-#define TARGET_ASM_FILE_END file_end_indicate_exec_stack
+#define TARGET_ASM_FILE_END aarch64_file_end_indicate_exec_stack
 
 /* Uninitialized common symbols in non-PIE executables, even with
    strong definitions in dependent shared libraries, will resolve
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 10b0bd2..1425943 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -18772,6 +18772,57 @@ aarch64_stack_protect_guard (void)
   return NULL_TREE;
 }
 
+/* Implement TARGET_ASM_FILE_END for AArch64.  This adds the AArch64 GNU NOTE
+   section at the end if needed.  */
+#define GNU_PROPERTY_AARCH64_FEATURE_1_AND	0xc0000000
+#define GNU_PROPERTY_AARCH64_FEATURE_1_BTI	(1U << 0)
+#define GNU_PROPERTY_AARCH64_FEATURE_1_PAC	(1U << 1)
+void
+aarch64_file_end_indicate_exec_stack ()
+{
+  file_end_indicate_exec_stack ();
+
+  unsigned feature_1_and = 0;
+  if (aarch64_bti_enabled ())
+    feature_1_and |= GNU_PROPERTY_AARCH64_FEATURE_1_BTI;
+
+  if (aarch64_ra_sign_scope != AARCH64_FUNCTION_NONE)
+    feature_1_and |= GNU_PROPERTY_AARCH64_FEATURE_1_PAC;
+
+  if (feature_1_and)
+    {
+      /* Generate .note.gnu.property section.  */
+      switch_to_section (get_section (".note.gnu.property",
+				      SECTION_NOTYPE, NULL));
+
+      /* PT_NOTE header: namesz, descsz, type.
+	 namesz = 4 ("GNU\0")
+	 descsz = 16 (Size of the program property array)
+		  [(12 + padding) * Number of array elements]
+	 type   = 5 (NT_GNU_PROPERTY_TYPE_0).  */
+      assemble_align (POINTER_SIZE);
+      assemble_integer (GEN_INT (4), 4, 32, 1);
+      assemble_integer (GEN_INT (ROUND_UP (12, POINTER_BYTES)), 4, 32, 1);
+      assemble_integer (GEN_INT (5), 4, 32, 1);
+
+      /* PT_NOTE name.  */
+      assemble_string ("GNU", 4);
+
+      /* PT_NOTE contents for NT_GNU_PROPERTY_TYPE_0:
+	 type   = GNU_PROPERTY_AARCH64_FEATURE_1_AND
+	 datasz = 4
+	 data   = feature_1_and.  */
+      assemble_integer (GEN_INT (GNU_PROPERTY_AARCH64_FEATURE_1_AND), 4, 32, 1);
+      assemble_integer (GEN_INT (4), 4, 32, 1);
+      assemble_integer (GEN_INT (feature_1_and), 4, 32, 1);
+
+      /* Pad the size of the note to the required alignment.  */
+      assemble_align (POINTER_SIZE);
+    }
+}
+#undef GNU_PROPERTY_AARCH64_FEATURE_1_PAC
+#undef GNU_PROPERTY_AARCH64_FEATURE_1_BTI
+#undef GNU_PROPERTY_AARCH64_FEATURE_1_AND
 
 /* Target-specific selftests.  */
 
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 81d6f26..76e1a8e 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,10 @@
+2018-04-23  Sudakshina Das  <sudi.das@arm.com>
+
+	* gcc.target/aarch64/bti-1.c: Add scan directive for gnu note section
+	for linux targets.
+	* gcc.target/aarch64/va_arg_1.c: Update scan directive to not clash
+	with GNU note section.
+
 2019-04-23  Jeff Law  <law@redhat.com>
 
 	* lib/target-supports.exp
diff --git a/gcc/testsuite/gcc.target/aarch64/bti-1.c b/gcc/testsuite/gcc.target/aarch64/bti-1.c
index a8c6041..5a556b0 100644
--- a/gcc/testsuite/gcc.target/aarch64/bti-1.c
+++ b/gcc/testsuite/gcc.target/aarch64/bti-1.c
@@ -61,3 +61,4 @@ lab2:
 }
 /* { dg-final { scan-assembler-times "hint\t34" 1 } } */
 /* { dg-final { scan-assembler-times "hint\t36" 12 } } */
+/* { dg-final { scan-assembler ".note.gnu.property" { target *-*-linux* } } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/va_arg_1.c b/gcc/testsuite/gcc.target/aarch64/va_arg_1.c
index e8e3cda..5bcb5f3 100644
--- a/gcc/testsuite/gcc.target/aarch64/va_arg_1.c
+++ b/gcc/testsuite/gcc.target/aarch64/va_arg_1.c
@@ -4,7 +4,7 @@
 int
 f (int a, ...)
 {
-  /* { dg-final { scan-assembler-not "str" } } */
+  /* { dg-final { scan-assembler-not "str\t" } } */
   return a;
 }