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authorJim Blandy <jimb@codesourcery.com>2004-08-24 21:01:49 +0000
committerJim Blandy <jimb@codesourcery.com>2004-08-24 21:01:49 +0000
commit87808bd699575a850139a1f916512ab7a47fd496 (patch)
tree16b075db667922d055eb918d2b4eaa76ffb51b14 /gdb/dwarf2expr.h
parent8d2c00cb73ae9b3d1e5d7317241dc02e575b7f1b (diff)
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* 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.
Diffstat (limited to 'gdb/dwarf2expr.h')
-rw-r--r--gdb/dwarf2expr.h43
1 files changed, 43 insertions, 0 deletions
diff --git a/gdb/dwarf2expr.h b/gdb/dwarf2expr.h
index 0a60edb..f22d085 100644
--- a/gdb/dwarf2expr.h
+++ b/gdb/dwarf2expr.h
@@ -74,6 +74,49 @@ struct dwarf_expr_context
/* Non-zero if the result is in a register. The register number
will be on the expression stack. */
int in_reg;
+
+ /* An array of pieces. PIECES points to its first element;
+ NUM_PIECES is its length.
+
+ Each time DW_OP_piece is executed, we add a new element to the
+ end of this array, recording the current top of the stack, the
+ current in_reg flag, and the size given as the operand to
+ DW_OP_piece. We then pop the top value from the stack, clear the
+ in_reg flag, and resume evaluation.
+
+ The Dwarf spec doesn't say whether DW_OP_piece pops the top value
+ from the stack. We do, ensuring that clients of this interface
+ expecting to see a value left on the top of the stack (say, code
+ evaluating frame base expressions or CFA's specified with
+ DW_CFA_def_cfa_expression) will get an error if the expression
+ actually marks all the values it computes as pieces.
+
+ If an expression never uses DW_OP_piece, num_pieces will be zero.
+ (It would be nice to present these cases as expressions yielding
+ a single piece, with in_reg clear, so that callers need not
+ distinguish between the no-DW_OP_piece and one-DW_OP_piece cases.
+ But expressions with no DW_OP_piece operations have no value to
+ place in a piece's 'size' field; the size comes from the
+ surrounding data. So the two cases need to be handled
+ separately.) */
+ int num_pieces;
+ struct dwarf_expr_piece *pieces;
+};
+
+
+/* A piece of an object, as recorded by DW_OP_piece. */
+struct dwarf_expr_piece
+{
+ /* If IN_REG is zero, then the piece is in memory, and VALUE is its address.
+ If IN_REG is non-zero, then the piece is in a register, and VALUE
+ is the register number. */
+ int in_reg;
+
+ /* This piece's address or register number. */
+ CORE_ADDR value;
+
+ /* The length of the piece, in bytes. */
+ ULONGEST size;
};
struct dwarf_expr_context *new_dwarf_expr_context (void);