From: Luis Machado <luis.machado@linaro.org>
Date: Thu, 7 Jan 2021 15:21:29 +0000 (-0300)
Subject: Handle unavailable LR/PC
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d2746b652ccb1e53afbf91d2ed42e676ee20b5fe;p=thirdparty%2Fbinutils-gdb.git

Handle unavailable LR/PC

This fixes a situation where LR/PC is not available, so we need to throw
an error rather than continuing.

gdb/ChangeLog:

2021-01-15  Luis Machado  <luis.machado@arm.com>

	* aarch64-tdep.c (aarch64_prologue_prev_register)
	(aarch64_dwarf2_prev_register): Throw error if LR is optimized out.
---

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 760765b6ff3..f454cf3c1f2 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2021-01-15  Luis Machado  <luis.machado@arm.com>
+
+	* aarch64-tdep.c (aarch64_prologue_prev_register)
+	(aarch64_dwarf2_prev_register): Throw error if LR is optimized out.
+
 2021-01-15  Luis Machado  <luis.machado@arm.com>
 
 	* Makefile.in (HFILES_NO_SRCDIR): Add nat/aarch64-cap-linux.h.
diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index e1792e70a49..d805040c86a 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -1413,6 +1413,12 @@ aarch64_prologue_prev_register (struct frame_info *this_frame,
       struct value *lr_value = frame_unwind_register_value (this_frame,
 							    lr_regnum);
 
+      /* Make sure LR is available. If not, there is nothing we can do.  */
+      if (lr_value == nullptr || (lr_value != nullptr
+				  && value_optimized_out (lr_value)))
+	throw_error (OPTIMIZED_OUT_ERROR, _("Register %d was not saved"),
+		     prev_regnum);
+
       /* Extract only the bottom 8 bytes of CLR.  This truncates the capability
 	 to 8 bytes.  For LR, this gets us the whole register.  */
       lr = extract_unsigned_integer (value_contents_all (lr_value), 8,
@@ -1607,8 +1613,14 @@ aarch64_dwarf2_prev_register (struct frame_info *this_frame,
       else
 	lr_regnum = tdep->cap_reg_clr;
 
-       struct value *lr_value = frame_unwind_register_value (this_frame,
-							     lr_regnum);
+      struct value *lr_value = frame_unwind_register_value (this_frame,
+							    lr_regnum);
+
+      /* Make sure LR is available. If not, there is nothing we can do.  */
+      if (lr_value == nullptr || (lr_value != nullptr
+				  && value_optimized_out (lr_value)))
+	throw_error (OPTIMIZED_OUT_ERROR, _("Register %d was not saved"),
+		     regnum);
 
       /* Extract only the bottom 8 bytes of CLR.  This truncates the capability
 	 to 8 bytes.  For LR, this gets us the whole register.  */