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authorTom Tromey <tromey@adacore.com>2020-04-24 13:40:31 -0600
committerTom Tromey <tromey@adacore.com>2020-04-24 13:40:31 -0600
commitb249d2c2c01775fb015b38b272389b8693e414f6 (patch)
tree5c41219789c65cf9f6f65f46568a432c063f68c4 /gdb/dwarf2/loc.h
parent61122aa9ed4096c3d85b01d52a0c0f67fb441533 (diff)
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Prefer existing data when evaluating DWARF expression
When evaluating a DWARF expression, the dynamic type resolution code will pass in a buffer of bytes via the property_addr_info. However, the DWARF expression evaluator will then proceed to read memory from the inferior, even when the request could be filled from this buffer. This, in turn, is a problem in some cases; and specifically when trying to handle the Ada scenario of extracting a variable-length value from a packed array. Here, the ordinary DWARF expression cannot be directly evaluated, because the data may appear at some arbitrary bit offset. So, it is unpacked into a staging area and then the expression is evaluated -- using an address of 0. This patch fixes the problem by arranging for the DWARF evaluator, in this case, to prefer passed-in memory when possible. The type of the buffer in the property_addr_info is changed to an array_view so that bounds checking can be done. gdb/ChangeLog 2020-04-24 Tom Tromey <tromey@adacore.com> * ada-lang.c (ada_discrete_type_high_bound, ada_discrete_type_low) (ada_value_primitive_packed_val): Update. * ada-valprint.c (ada_value_print_1): Update. * dwarf2/loc.c (evaluate_for_locexpr_baton): New struct. (dwarf2_locexpr_baton_eval): Take a property_addr_info rather than just an address. Use evaluate_for_locexpr_baton. (dwarf2_evaluate_property): Update. * dwarf2/loc.h (struct property_addr_info) <valaddr>: Now an array_view. * findvar.c (default_read_var_value): Update. * gdbtypes.c (compute_variant_fields_inner) (resolve_dynamic_type_internal): Update. (resolve_dynamic_type): Change type of valaddr parameter. * gdbtypes.h (resolve_dynamic_type): Update. * valarith.c (value_subscripted_rvalue): Update. * value.c (value_from_contents_and_address): Update.
Diffstat (limited to 'gdb/dwarf2/loc.h')
-rw-r--r--gdb/dwarf2/loc.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/gdb/dwarf2/loc.h b/gdb/dwarf2/loc.h
index 6ff9b79..9815368 100644
--- a/gdb/dwarf2/loc.h
+++ b/gdb/dwarf2/loc.h
@@ -73,7 +73,7 @@ struct property_addr_info
struct type *type;
/* If not NULL, a buffer containing the object's value. */
- const gdb_byte *valaddr;
+ gdb::array_view<const gdb_byte> valaddr;
/* The address of that object. */
CORE_ADDR addr;