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author | Jim Blandy <jimb@codesourcery.com> | 2004-08-24 21:01:49 +0000 |
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committer | Jim Blandy <jimb@codesourcery.com> | 2004-08-24 21:01:49 +0000 |
commit | 87808bd699575a850139a1f916512ab7a47fd496 (patch) | |
tree | 16b075db667922d055eb918d2b4eaa76ffb51b14 /gdb/dwarf2expr.h | |
parent | 8d2c00cb73ae9b3d1e5d7317241dc02e575b7f1b (diff) | |
download | gdb-87808bd699575a850139a1f916512ab7a47fd496.zip gdb-87808bd699575a850139a1f916512ab7a47fd496.tar.gz gdb-87808bd699575a850139a1f916512ab7a47fd496.tar.bz2 |
* 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.h | 43 |
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); |