Handle biased types
authorTom Tromey <tromey@adacore.com>
Mon, 13 May 2019 19:21:48 +0000 (13:21 -0600)
committerTom Tromey <tromey@adacore.com>
Tue, 3 Sep 2019 16:20:40 +0000 (10:20 -0600)
commit4e962e74e45f2b0365e5b21504f33480c468ff00
tree7f20b55fbf46c379db243e1bcbf8a84ccd55c028
parentf44b758d3133ef0a7f3131c1e12ed20feb33ee61
Handle biased types

In Ada, the programmer can request that a range type with a non-zero
base be stored in the minimal number of bits required for the range.
This is done by biasing the values; so, for example, a range of -7..-4
may be stored as two bits with a bias of -7.

This patch implements this for gdb.  It is done by adding a bias to
struct range_bounds and then adjusting a few spots to handle this.

The test case is written to use -fgnat-encodings=minimal, but a future
compiler patch will change the compiler to emit DW_AT_GNU_bias with
-fgnat-encodings=gdb.  It seemed good to get the gdb patch in first.

Tested on x86-64 Fedora 29; plus a variety of targets using AdaCore's
internal test suite.

gdb/ChangeLog
2019-09-03  Tom Tromey  <tromey@adacore.com>

* ada-valprint.c (ada_val_print_num): Don't recurse for range
types.
(has_negatives): Unbias a range type bound.
* dwarf2read.c (read_subrange_type): Handle DW_AT_GNU_bias.
* gdbtypes.c (operator==): Handle new field.
(create_range_type): Add "bias" parameter.
(create_static_range_type, resolve_dynamic_range): Update.
* gdbtypes.h (struct range_bounds) <bias>: New member.
(create_range_type): Add bias parameter.
* printcmd.c (print_scalar_formatted): Unbias range types.
* value.c (unpack_long): Unbias range types.
(pack_long): Bias range types.

gdb/testsuite/ChangeLog
2019-09-03  Tom Tromey  <tromey@adacore.com>

* gdb.ada/bias.exp: New file.
* gdb.ada/bias/bias.adb: New file.
* gdb.ada/print_chars.exp: Add regression test.
* gdb.ada/print_chars/foo.adb (My_Character): New type.
(MC): New variable.
15 files changed:
gdb/ChangeLog
gdb/ada-lang.c
gdb/ada-valprint.c
gdb/dwarf2read.c
gdb/gdbtypes.c
gdb/gdbtypes.h
gdb/printcmd.c
gdb/testsuite/ChangeLog
gdb/testsuite/gdb.ada/bias.exp [new file with mode: 0644]
gdb/testsuite/gdb.ada/bias/bias.adb [new file with mode: 0644]
gdb/testsuite/gdb.ada/bias/pck.adb [new file with mode: 0644]
gdb/testsuite/gdb.ada/bias/pck.ads [new file with mode: 0644]
gdb/testsuite/gdb.ada/print_chars.exp
gdb/testsuite/gdb.ada/print_chars/foo.adb
gdb/value.c