* dwarf2expr.h (struct dwarf_expr_context): New members

'num_pieces' and 'pieces', for returning the result of an
expression that uses DW_OP_piece.
(struct dwarf_expr_piece): New struct type.
* dwarf2expr.c (new_dwarf_expr_context): Initialize num_pieces and
pieces.
(free_dwarf_expr_context): Free pieces, if any.
(add_piece): New function.
(execute_stack_op): Implement DW_OP_piece.
* dwarf2loc.c (dwarf2_evaluate_loc_desc): If the result of the
expression is a list of pieces, print an error message.
(dwarf2_loc_desc_needs_frame): If the expression yields
pieces, and any piece is in a register, then we need a frame.

1 files changed, 42 insertions, 0 deletions

diff --git a/gdb/dwarf2expr.c b/gdb/dwarf2expr.c
index 294afa0..a60e5a9 100644
--- a/gdb/dwarf2expr.c
+++ b/gdb/dwarf2expr.c
@@ -42,6 +42,8 @@ new_dwarf_expr_context (void)
   retval->stack_len = 0;
   retval->stack_allocated = 10;
   retval->stack = xmalloc (retval->stack_allocated * sizeof (CORE_ADDR));
+  retval->num_pieces = 0;
+  retval->pieces = 0;
   return retval;
 }
 
@@ -51,6 +53,7 @@ void
 free_dwarf_expr_context (struct dwarf_expr_context *ctx)
 {
   xfree (ctx->stack);
+  xfree (ctx->pieces);
   xfree (ctx);
 }
 
@@ -100,6 +103,29 @@ dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n)
 
 }
 
+/* Add a new piece to CTX's piece list.  */
+static void
+add_piece (struct dwarf_expr_context *ctx,
+           int in_reg, CORE_ADDR value, ULONGEST size)
+{
+  struct dwarf_expr_piece *p;
+
+  ctx->num_pieces++;
+
+  if (ctx->pieces)
+    ctx->pieces = xrealloc (ctx->pieces,
+                            (ctx->num_pieces
+                             * sizeof (struct dwarf_expr_piece)));
+  else
+    ctx->pieces = xmalloc (ctx->num_pieces
+                           * sizeof (struct dwarf_expr_piece));
+
+  p = &ctx->pieces[ctx->num_pieces - 1];
+  p->in_reg = in_reg;
+  p->value = value;
+  p->size = size;
+}
+
 /* Evaluate the expression at ADDR (LEN bytes long) using the context
    CTX.  */
 
@@ -661,6 +687,22 @@ execute_stack_op (struct dwarf_expr_context *ctx, unsigned char *op_ptr,
 	case DW_OP_nop:
 	  goto no_push;
 
+        case DW_OP_piece:
+          {
+            ULONGEST size;
+            CORE_ADDR addr_or_regnum;
+
+            /* Record the piece.  */
+            op_ptr = read_uleb128 (op_ptr, op_end, &size);
+            addr_or_regnum = dwarf_expr_fetch (ctx, 0);
+            add_piece (ctx, ctx->in_reg, addr_or_regnum, size);
+
+            /* Pop off the address/regnum, and clear the in_reg flag.  */
+            dwarf_expr_pop (ctx);
+            ctx->in_reg = 0;
+          }
+          goto no_push;
+
 	default:
 	  error ("Unhandled dwarf expression opcode 0x%x", op);
 	}