RISC-V: Add .note.gnu.property for ZICFILP and ZICFISS ISA extension

gcc/ChangeLog:
	* config/riscv/riscv.cc
	(riscv_file_end): Add .note.gnu.property.

libgcc/ChangeLog:
	* config/riscv/crti.S: Add lpad instructions.
	* config/riscv/crtn.S: Likewise.
	* config/riscv/save-restore.S: Likewise.
	* config/riscv/riscv-asm.h: Add GNU_PROPERTY for ZICFILP,
	ZICFISS.

	Co-Developed-by: Jesse Huang <jesse.huang@sifive.com>

4 files changed, 77 insertions, 1 deletions

diff --git a/libgcc/config/riscv/crti.S b/libgcc/config/riscv/crti.S
index 89bac70..3a67fd7 100644
--- a/libgcc/config/riscv/crti.S
+++ b/libgcc/config/riscv/crti.S
@@ -1 +1,3 @@
 /* crti.S is empty because .init_array/.fini_array are used exclusively. */
+
+#include "riscv-asm.h"
diff --git a/libgcc/config/riscv/crtn.S b/libgcc/config/riscv/crtn.S
index ca6ee7b..cb80782 100644
--- a/libgcc/config/riscv/crtn.S
+++ b/libgcc/config/riscv/crtn.S
@@ -1 +1,3 @@
 /* crtn.S is empty because .init_array/.fini_array are used exclusively. */
+
+#include "riscv-asm.h"
diff --git a/libgcc/config/riscv/riscv-asm.h b/libgcc/config/riscv/riscv-asm.h
index b6dbeae..73bddb3 100644
--- a/libgcc/config/riscv/riscv-asm.h
+++ b/libgcc/config/riscv/riscv-asm.h
@@ -23,9 +23,11 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
 #define FUNC_SIZE(X)	.size X,.-X
 
 #define FUNC_BEGIN(X)		\
+	.align 2;		\
 	.globl X;		\
 	FUNC_TYPE (X);		\
-X:
+X:				\
+	LPAD
 
 #define FUNC_END(X)		\
 	FUNC_SIZE(X)
@@ -39,3 +41,68 @@ X:
 #define HIDDEN_JUMPTARGET(X)	CONCAT1(__hidden_, X)
 #define HIDDEN_DEF(X)		FUNC_ALIAS(HIDDEN_JUMPTARGET(X), X);     \
 				.hidden HIDDEN_JUMPTARGET(X)
+
+/* GNU_PROPERTY_RISCV64_* macros from elf.h for use in asm code.  */
+#define FEATURE_1_AND 0xc0000000
+#define FEATURE_1_FCFI 1
+#define FEATURE_1_BCFI 2
+
+/* Add a NT_GNU_PROPERTY_TYPE_0 note.  */
+#if __riscv_xlen == 32
+#  define GNU_PROPERTY(type, value)	\
+    .section .note.gnu.property, "a";	\
+    .p2align 2;				\
+    .word 4;				\
+    .word 12;				\
+    .word 5;				\
+    .asciz "GNU";			\
+    .word type;				\
+    .word 4;				\
+    .word value;			\
+    .text
+#else
+#  define GNU_PROPERTY(type, value)	\
+    .section .note.gnu.property, "a";	\
+    .p2align 3;				\
+    .word 4;				\
+    .word 16;				\
+    .word 5;				\
+    .asciz "GNU";			\
+    .word type;				\
+    .word 4;				\
+    .word value;			\
+    .word 0;				\
+    .text
+#endif
+
+/* Add GNU property note with the supported features to all asm code
+   where sysdep.h is included.  */
+#undef __VALUE_FOR_FEATURE_1_AND
+#if defined (__riscv_zicfilp) || defined (__riscv_zicfiss)
+#  if defined (__riscv_zicfilp)
+#    if defined (__riscv_zicfiss)
+#      define __VALUE_FOR_FEATURE_1_AND 0x3
+#    else
+#      define __VALUE_FOR_FEATURE_1_AND 0x1
+#    endif
+#  else
+#    if defined (__riscv_zicfiss)
+#      define __VALUE_FOR_FEATURE_1_AND 0x2
+#    else
+#      error "What?"
+#    endif
+#  endif
+#endif
+
+#if defined (__VALUE_FOR_FEATURE_1_AND)
+GNU_PROPERTY (FEATURE_1_AND, __VALUE_FOR_FEATURE_1_AND)
+#endif
+#undef __VALUE_FOR_FEATURE_1_AND
+
+#ifdef __riscv_zicfilp
+# define SET_LPAD   lui  t2, 0
+# define LPAD       lpad 0
+#else
+# define SET_LPAD
+# define LPAD
+#endif
diff --git a/libgcc/config/riscv/save-restore.S b/libgcc/config/riscv/save-restore.S
index ae8312d..fc65447 100644
--- a/libgcc/config/riscv/save-restore.S
+++ b/libgcc/config/riscv/save-restore.S
@@ -137,6 +137,7 @@ FUNC_BEGIN (__riscv_save_2)
   # CFA info is not correct in next 2 instruction since t1's
   # value is depend on how may register really save.
   add sp, sp, t1
+  SET_LPAD
   jr t0
   .cfi_endproc
 FUNC_END (__riscv_save_12)
@@ -162,6 +163,7 @@ FUNC_BEGIN (__riscv_save_0)
   .cfi_offset 8, -16
   sd ra, 8(sp)
   .cfi_offset 1, -8
+  SET_LPAD
   jr t0
   .cfi_endproc
 FUNC_END (__riscv_save_1)
@@ -310,6 +312,7 @@ FUNC_BEGIN(__riscv_save_0)
   .cfi_offset 8, -8
   sw ra, 8(sp)
   .cfi_offset 1, -4
+  SET_LPAD
   jr t0
   .cfi_endproc
 FUNC_END(__riscv_save_2)
@@ -399,6 +402,7 @@ FUNC_BEGIN (__riscv_save_4)
   # CFA info is not correct in next 2 instruction since t1's
   # value is depend on how may register really save.
   sub sp, sp, t1
+  SET_LPAD
   jr t0
   .cfi_endproc
 FUNC_END (__riscv_save_12)
@@ -428,6 +432,7 @@ FUNC_BEGIN (__riscv_save_0)
   .cfi_offset 8, -8
   sw ra, 12(sp)
   .cfi_offset 1, -4
+  SET_LPAD
   jr t0
   .cfi_endproc
 FUNC_END (__riscv_save_3)