[PATCH 9/12] arm: Make libgcc bti compatible

[Andrea Corallo via Gcc-patches]

This change add bti instructions at the beginning of arm specific
libgcc hand written assembly routines.

2022-03-31  Andrea Corallo  <andrea.cora...@arm.com>

        * libgcc/config/arm/crti.S (FUNC_START): Add bti instruction if
        necessary.
        * libgcc/config/arm/lib1funcs.S (THUMB_FUNC_START, FUNC_START):
        Likewise.


diff --git a/libgcc/config/arm/crti.S b/libgcc/config/arm/crti.S
index 0192972a7e6..bac2d87fbb9 100644
--- a/libgcc/config/arm/crti.S
+++ b/libgcc/config/arm/crti.S
@@ -51,7 +51,9 @@
 .macro FUNC_START
 #ifdef __thumb__
        .thumb
-       
+#if defined(__ARM_FEATURE_BTI)
+       bti
+#endif
        push    {r3, r4, r5, r6, r7, lr}
 #else
        .arm
diff --git a/libgcc/config/arm/lib1funcs.S b/libgcc/config/arm/lib1funcs.S
index 8c39c9f20a2..45dfb5da9ee 100644
--- a/libgcc/config/arm/lib1funcs.S
+++ b/libgcc/config/arm/lib1funcs.S
@@ -345,6 +345,9 @@ LSYM(Ldiv0):
        TYPE    (\name)
        .thumb_func
 SYM (\name):
+#if defined(__ARM_FEATURE_BTI)
+       bti
+#endif
 .endm
 
 /* Function start macros.  Variants for ARM and Thumb.  */
@@ -372,6 +375,9 @@ SYM (\name):
        THUMB_FUNC
        THUMB_SYNTAX
 SYM (__\name):
+#if defined(__ARM_FEATURE_BTI)
+       bti
+#endif
 .endm
 
 .macro ARM_SYM_START name