Return early in target_xfer_partial when LEN is zero.

[deliverable/binutils-gdb.git] / gdb / findvar.c

diff --git a/gdb/findvar.c b/gdb/findvar.c
index fdce436baac214f2ed2fddd06cbe3c904e481472..0647c0f1331306944ca9b650829cd3e5de587f1c 100644 (file)
--- a/gdb/findvar.c
+++ b/gdb/findvar.c
@@ -1,6 +1,6 @@
 /* Find a variable's value in memory, for GDB, the GNU debugger.
 
-   Copyright (C) 1986-2013 Free Software Foundation, Inc.
+   Copyright (C) 1986-2014 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
@@ -25,7 +25,7 @@
 #include "gdbcore.h"
 #include "inferior.h"
 #include "target.h"
-#include "gdb_string.h"
+#include <string.h>
 #include "gdb_assert.h"
 #include "floatformat.h"
 #include "symfile.h"           /* for overlay functions */
@@ -262,13 +262,7 @@ struct value *
 value_of_register (int regnum, struct frame_info *frame)
 {
   struct gdbarch *gdbarch = get_frame_arch (frame);
-  CORE_ADDR addr;
-  int optim;
-  int unavail;
   struct value *reg_val;
-  int realnum;
-  gdb_byte raw_buffer[MAX_REGISTER_SIZE];
-  enum lval_type lval;
 
   /* User registers lie completely outside of the range of normal
      registers.  Catch them early so that the target never sees them.  */
@@ -276,25 +270,8 @@ value_of_register (int regnum, struct frame_info *frame)
                + gdbarch_num_pseudo_regs (gdbarch))
     return value_of_user_reg (regnum, frame);
 
-  frame_register (frame, regnum, &optim, &unavail,
-                 &lval, &addr, &realnum, raw_buffer);
-
-  reg_val = allocate_value (register_type (gdbarch, regnum));
-
-  if (!optim && !unavail)
-    memcpy (value_contents_raw (reg_val), raw_buffer,
-           register_size (gdbarch, regnum));
-  else
-    memset (value_contents_raw (reg_val), 0,
-           register_size (gdbarch, regnum));
-
-  VALUE_LVAL (reg_val) = lval;
-  set_value_address (reg_val, addr);
-  VALUE_REGNUM (reg_val) = regnum;
-  set_value_optimized_out (reg_val, optim);
-  if (unavail)
-    mark_value_bytes_unavailable (reg_val, 0, register_size (gdbarch, regnum));
-  VALUE_FRAME_ID (reg_val) = get_frame_id (frame);
+  reg_val = value_of_register_lazy (frame, regnum);
+  value_fetch_lazy (reg_val);
   return reg_val;
 }
 
@@ -498,7 +475,6 @@ default_read_var_value (struct symbol *var, struct frame_info *frame)
       return v;
 
     case LOC_STATIC:
-      v = allocate_value_lazy (type);
       if (overlay_debugging)
        addr = symbol_overlayed_address (SYMBOL_VALUE_ADDRESS (var),
                                         SYMBOL_OBJ_SECTION (SYMBOL_OBJFILE (var),
@@ -513,7 +489,6 @@ default_read_var_value (struct symbol *var, struct frame_info *frame)
        error (_("Unknown argument list address for `%s'."),
               SYMBOL_PRINT_NAME (var));
       addr += SYMBOL_VALUE (var);
-      v = allocate_value_lazy (type);
       break;
 
     case LOC_REF_ARG:
@@ -528,14 +503,12 @@ default_read_var_value (struct symbol *var, struct frame_info *frame)
        argref += SYMBOL_VALUE (var);
        ref = value_at (lookup_pointer_type (type), argref);
        addr = value_as_address (ref);
-       v = allocate_value_lazy (type);
        break;
       }
 
     case LOC_LOCAL:
       addr = get_frame_locals_address (frame);
       addr += SYMBOL_VALUE (var);
-      v = allocate_value_lazy (type);
       break;
 
     case LOC_TYPEDEF:
@@ -544,7 +517,6 @@ default_read_var_value (struct symbol *var, struct frame_info *frame)
       break;
 
     case LOC_BLOCK:
-      v = allocate_value_lazy (type);
       if (overlay_debugging)
        addr = symbol_overlayed_address
          (BLOCK_START (SYMBOL_BLOCK_VALUE (var)), SYMBOL_OBJ_SECTION (SYMBOL_OBJFILE (var),
@@ -571,7 +543,6 @@ default_read_var_value (struct symbol *var, struct frame_info *frame)
                     SYMBOL_PRINT_NAME (var));
 
            addr = value_as_address (regval);
-           v = allocate_value_lazy (type);
          }
        else
          {
@@ -616,7 +587,6 @@ default_read_var_value (struct symbol *var, struct frame_info *frame)
        if (obj_section
            && (obj_section->the_bfd_section->flags & SEC_THREAD_LOCAL) != 0)
          addr = target_translate_tls_address (obj_section->objfile, addr);
-       v = allocate_value_lazy (type);
       }
       break;
 
@@ -629,8 +599,7 @@ default_read_var_value (struct symbol *var, struct frame_info *frame)
       break;
     }
 
-  VALUE_LVAL (v) = lval_memory;
-  set_value_address (v, addr);
+  v = value_at_lazy (type, addr);
   return v;
 }
 
@@ -788,6 +757,15 @@ address_from_register (struct type *type, int regnum, struct frame_info *frame)
   value = value_from_register (type, regnum, frame);
   gdb_assert (value);
 
+  if (value_optimized_out (value))
+    {
+      /* This function is used while computing a location expression.
+        Complain about the value being optimized out, rather than
+        letting value_as_address complain about some random register
+        the expression depends on not being saved.  */
+      error_value_optimized_out ();
+    }
+
   result = value_as_address (value);
   release_value (value);
   value_free (value);