forked from Imagelibrary/binutils-gdb
85c7cb3c4b
In C++ it is possible to use an empty enum as a strong typedef. For
example, a user could write:
enum class my_type : unsigned char {};
Now my_type can be used like 'unsigned char' except the compiler will
not allow implicit conversion too and from the native 'unsigned char'
type.
This is used in the standard library for things like std::byte.
Currently, when GDB prints a value of type my_type, it looks like
this:
(gdb) print my_var
$1 = (unknown: 0x4)
Which isn't great. This gets worse when we consider something like:
std::vector<my_type> vec;
When using a pretty-printer, this could look like this:
std::vector of length 2, capacity 2 = {(unknown: 0x2), (unknown: 0x4)}
Clearly not great. This is described in PR gdb/30148.
The problem here is in dwarf2/read.c, we assume all enums are flag
enums unless we find an enumerator with a non-flag like value.
Clearly an empty enum contains no non-flag values, so we assume the
enum is a flag enum.
I propose adding an extra check here; that is, an empty enum should
never be a flag enum.
With this the above cases look more like:
(gdb) print my_var
$1 = 4
and:
std::vector of length 2, capacity 2 = {2, 4}
Which look much better.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30148
Reviewed-By: Tom Tromey <tom@tromey.com>
32 lines
874 B
C++
32 lines
874 B
C++
/* Copyright 2023 Free Software Foundation, Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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enum enum1 {};
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enum class enum2 : unsigned char {};
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void
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breakpt (enum1 arg1, enum2 arg2)
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{
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/* Nothing. */
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}
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int
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main ()
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{
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breakpt ((enum1) 8, (enum2) 4);
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return 0;
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}
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