[PATCH] [AArch64] Extend the prologue analyzer to handle the bti instruction

[Luis Machado]

Handle the BTI instruction in the prologue analyzer.
---
 gdb/aarch64-tdep.c      | 36 ++++++++++++++++++++++++++++++++++++
 gdb/arch/aarch64-insn.h |  5 +++++
 2 files changed, 41 insertions(+)

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 42b8494980c..8c64f56fbe0 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -515,6 +515,9 @@ aarch64_analyze_prologue (struct gdbarch *gdbarch,
 	      /* Return addresses are not mangled.  */
 	      ra_state_val = 0;
 	    }
+	  else if (IS_BTI (insn))
+	    /* We don't need to do anything special for a BTI instruction.  */
+	    continue;
 	  else
 	    {
 	      aarch64_debug_printf ("prologue analysis gave up addr=%s"
@@ -869,6 +872,39 @@ aarch64_analyze_prologue_test (void)
 	  SELF_CHECK (cache.saved_regs[regnum].is_value ());
 	}
     }
+
+  /* Test a prologue with a BTI instruction.  */
+    {
+      static const uint32_t insns[] = {
+	0xd503245f, /* bti */
+	0xa9bd7bfd, /* stp	x29, x30, [sp, #-48]! */
+	0x910003fd, /* mov	x29, sp */
+	0xf801c3f3, /* str	x19, [sp, #28] */
+	0xb9401fa0, /* ldr	x19, [x29, #28] */
+      };
+      instruction_reader_test reader (insns);
+
+      trad_frame_reset_saved_regs (gdbarch, cache.saved_regs);
+      CORE_ADDR end = aarch64_analyze_prologue (gdbarch, 0, 128, &cache,
+						reader);
+
+      SELF_CHECK (end == 4 * 4);
+      SELF_CHECK (cache.framereg == AARCH64_FP_REGNUM);
+      SELF_CHECK (cache.framesize == 48);
+
+      for (int i = 0; i < AARCH64_X_REGISTER_COUNT; i++)
+	{
+	  if (i == 19)
+	    SELF_CHECK (cache.saved_regs[i].addr () == -20);
+	  else if (i == AARCH64_FP_REGNUM)
+	    SELF_CHECK (cache.saved_regs[i].addr () == -48);
+	  else if (i == AARCH64_LR_REGNUM)
+	    SELF_CHECK (cache.saved_regs[i].addr () == -40);
+	  else
+	    SELF_CHECK (cache.saved_regs[i].is_realreg ()
+			&& cache.saved_regs[i].realreg () == i);
+	}
+    }
 }
 } // namespace selftests
 #endif /* GDB_SELF_TEST */
diff --git a/gdb/arch/aarch64-insn.h b/gdb/arch/aarch64-insn.h
index 6f9ec8572b2..a05a6077922 100644
--- a/gdb/arch/aarch64-insn.h
+++ b/gdb/arch/aarch64-insn.h
@@ -42,6 +42,11 @@ extern bool aarch64_debug;
 #define sbits(obj,st,fn) \
   ((long) (bits(obj,st,fn) | ((long) bit(obj,fn) * ~ submask (fn - st))))
 
+/* Prologue analyzer helper macros.  */
+
+/* Is the instruction "bti"?  */
+#define IS_BTI(instruction) ((instruction & 0xffffff3f) == 0xd503241f)
+
 /* List of opcodes that we need for building the jump pad and relocating
    an instruction.  */
 
-- 
2.25.1