From c632ec404b12ecdd3ed2c2d59d48d61883ebc1d6 Mon Sep 17 00:00:00 2001
From: Bernhard Heckel <bernhard.heckel@intel.com>
Date: Tue, 6 Sep 2016 09:00:54 +0200
Subject: Dwarf: Fix dynamic properties with neg. value.

Evaluating of neg. value of 32bit inferiours running on 64bit plattform
causes issues because of the missing sign bits.

Bernhard Heckel  <bernhard.heckel@intel.com>

gdb/Changelog
	* dwarf2loc.h: Declare
	* dwarf2loc.c (dwarf2_evaluate_property_signed): New.
	  (dwarf2_evaluate_property): Delegate tasks to
	  dwarf2_evaluate_property_signed.

Change-Id: I3e8f67ecd0d78c579253f67cdf836bd8129a1a26
---
 gdb/dwarf2loc.c | 46 ++++++++++++++++++++++++++++++++++++++--------
 gdb/dwarf2loc.h |  6 ++++++
 2 files changed, 44 insertions(+), 8 deletions(-)

diff --git a/gdb/dwarf2loc.c b/gdb/dwarf2loc.c
index 548e468..560e16f 100644
--- a/gdb/dwarf2loc.c
+++ b/gdb/dwarf2loc.c
@@ -2601,11 +2601,14 @@ dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
 /* See dwarf2loc.h.  */
 
 int
-dwarf2_evaluate_property (const struct dynamic_prop *prop,
+dwarf2_evaluate_property_signed (const struct dynamic_prop *prop,
 			  struct frame_info *frame,
 			  struct property_addr_info *addr_stack,
-			  CORE_ADDR *value)
+			  CORE_ADDR *value,
+			  int is_signed)
 {
+  int rc = 0;
+
   if (prop == NULL)
     return 0;
 
@@ -2629,7 +2632,7 @@ dwarf2_evaluate_property (const struct dynamic_prop *prop,
 
 		*value = value_as_address (val);
 	      }
-	    return 1;
+	    rc = 1;
 	  }
       }
       break;
@@ -2651,7 +2654,7 @@ dwarf2_evaluate_property (const struct dynamic_prop *prop,
 	    if (!value_optimized_out (val))
 	      {
 		*value = value_as_address (val);
-		return 1;
+		rc = 1;
 	      }
 	  }
       }
@@ -2659,8 +2662,8 @@ dwarf2_evaluate_property (const struct dynamic_prop *prop,
 
     case PROP_CONST:
       *value = prop->data.const_val;
-      return 1;
-
+      rc = 1;
+      break;
     case PROP_ADDR_OFFSET:
       {
 	struct dwarf2_property_baton *baton
@@ -2681,11 +2684,38 @@ dwarf2_evaluate_property (const struct dynamic_prop *prop,
 	  val = value_at (baton->offset_info.type,
 			  pinfo->addr + baton->offset_info.offset);
 	*value = value_as_address (val);
-	return 1;
+	rc = 1;
       }
+      break;
     }
 
-  return 0;
+  if (rc == 1 && is_signed == 1)
+    {
+      /* If we have a valid return candidate and it's value is signed,
+         we have to sign-extend the value because CORE_ADDR on 64bit machine has
+         8 bytes but address size of an 32bit application is 4 bytes.  */
+      struct gdbarch * gdbarch = target_gdbarch ();
+      const int addr_bit = gdbarch_addr_bit (gdbarch);
+      const CORE_ADDR neg_mask = ((~0) <<  (addr_bit - 1));
+
+      /* Check if signed bit is set and sign-extend values.  */
+      if (*value & (neg_mask))
+	*value |= (neg_mask );
+    }
+  return rc;
+}
+
+int
+dwarf2_evaluate_property (const struct dynamic_prop *prop,
+			  struct frame_info *frame,
+			  struct property_addr_info *addr_stack,
+			  CORE_ADDR *value)
+{
+  return dwarf2_evaluate_property_signed (prop,
+				   frame,
+				   addr_stack,
+				   value,
+				   0);
 }
 
 /* See dwarf2loc.h.  */
diff --git a/gdb/dwarf2loc.h b/gdb/dwarf2loc.h
index fa83459..da6b9cd 100644
--- a/gdb/dwarf2loc.h
+++ b/gdb/dwarf2loc.h
@@ -138,6 +138,12 @@ int dwarf2_evaluate_property (const struct dynamic_prop *prop,
 			      struct property_addr_info *addr_stack,
 			      CORE_ADDR *value);
 
+int dwarf2_evaluate_property_signed (const struct dynamic_prop *prop,
+			      struct frame_info *frame,
+			      struct property_addr_info *addr_stack,
+			      CORE_ADDR *value,
+			      int is_signed);
+
 /* A helper for the compiler interface that compiles a single dynamic
    property to C code.
 
-- 
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