-/* Dwarf2 Expression Evaluator
- Copyright 2001, 2002, 2003 Free Software Foundation, Inc.
- Contributed by Daniel Berlin (dan@dberlin.org)
+/* DWARF 2 Expression Evaluator.
+
+ Copyright 2001, 2002, 2003, 2005 Free Software Foundation, Inc.
+
+ Contributed by Daniel Berlin <dan@dberlin.org>.
+
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
to all of the callback functions. */
void *baton;
- /* Return the value of register number REGNUM. LVALP will be set
- to the kind of lval this register is (generally lval_register
- for the current frame's registers or lval_memory for a register
- saved to the stack). For lval_memory ADDRP will be set to the
- saved location of the register. */
- CORE_ADDR (*read_reg) (void *baton, int regnum, enum lval_type *lvalp,
- CORE_ADDR *addrp);
+ /* Return the value of register number REGNUM. */
+ CORE_ADDR (*read_reg) (void *baton, int regnum);
/* Read LENGTH bytes at ADDR into BUF. */
- void (*read_mem) (void *baton, char *buf, CORE_ADDR addr,
- size_t length);
+ void (*read_mem) (void *baton, gdb_byte *buf, CORE_ADDR addr, size_t length);
/* Return the location expression for the frame base attribute, in
START and LENGTH. The result must be live until the current
expression evaluation is complete. */
- void (*get_frame_base) (void *baton, unsigned char **start,
- size_t *length);
+ void (*get_frame_base) (void *baton, gdb_byte **start, size_t *length);
/* Return the thread-local storage address for
DW_OP_GNU_push_tls_address. */
int recursion_depth, max_recursion_depth;
/* Non-zero if the result is in a register. The register number
- will be in REGNUM, and the result will be the contents of the
- register. */
+ will be on the expression stack. */
int in_reg;
- /* If the result is in a register, the register number. */
- int regnum;
+ /* 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;
};
-struct dwarf_expr_context *new_dwarf_expr_context ();
+
+/* 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);
void free_dwarf_expr_context (struct dwarf_expr_context *ctx);
void dwarf_expr_push (struct dwarf_expr_context *ctx, CORE_ADDR value);
CORE_ADDR dwarf_expr_fetch (struct dwarf_expr_context *ctx, int n);
-unsigned char *read_uleb128 (unsigned char *buf, unsigned char *buf_end,
- ULONGEST * r);
-unsigned char *read_sleb128 (unsigned char *buf, unsigned char *buf_end,
- LONGEST * r);
+gdb_byte *read_uleb128 (gdb_byte *buf, gdb_byte *buf_end, ULONGEST * r);
+gdb_byte *read_sleb128 (gdb_byte *buf, gdb_byte *buf_end, LONGEST * r);
+CORE_ADDR dwarf2_read_address (gdb_byte *buf, gdb_byte *buf_end,
+ int *bytes_read);
-#endif
+#endif /* dwarf2expr.h */