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author | Tom de Vries <tdevries@suse.de> | 2024-05-06 14:23:25 +0200 |
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committer | Tom de Vries <tdevries@suse.de> | 2024-05-06 14:23:25 +0200 |
commit | 5edbb6ed920057df4cca423e3fc54f27f7685def (patch) | |
tree | 55b7979fbe479370db262b410fdb6ff1c03a2699 /gdb/testsuite/gdb.multi/attach-while-running.exp | |
parent | c8866e3ec5e23b394d1258d623ff337abc4cd41d (diff) | |
download | gdb-5edbb6ed920057df4cca423e3fc54f27f7685def.zip gdb-5edbb6ed920057df4cca423e3fc54f27f7685def.tar.gz gdb-5edbb6ed920057df4cca423e3fc54f27f7685def.tar.bz2 |
[gdb/exp] Redo cast handling for indirection
In commit ed8fd0a342f ("[gdb/exp] Fix cast handling for indirection"), I
introduced the behaviour that even though we have:
...
(gdb) p *a_loc ()
'a_loc' has unknown return type; cast the call to its declared return type
...
we get:
...
(gdb) p (char)*a_loc ()
$1 = 97 'a'
...
In other words, the unknown return type of a_loc is inferred from the cast,
effectually evaluating:
...
(gdb) p (char)*(char *)a_loc ()
...
This is convient for the case that errno is defined as:
...
#define errno (*__errno_location ())
...
and the return type of __errno_location is unknown but the macro definition is
known, such that we can use:
...
(gdb) p (int)errno
...
instead of
...
(gdb) p *(int *)__errno_location ()
...
However, as Pedro has pointed out in post-commit review [1], this makes it
harder to reason about the semantics of an expression.
For instance, this:
...
(gdb) p (long long)*a_loc ()"
...
would be evaluated without debug info as:
...
(gdb) p (long long)*(long long *)a_loc ()"
...
but with debug info as:
...
(gdb) p (long long)*(char *)a_loc ()"
...
Fix this by instead simply erroring out for this case:
...
(gdb) p (char)*a_loc ()
'a_loc' has unknown return type; cast the call to its declared return type
...
Tested on x86_64-linux.
Approved-By: Pedro Alves <pedro@palves.net>
[1] https://sourceware.org/pipermail/gdb-patches/2024-May/208821.html
Diffstat (limited to 'gdb/testsuite/gdb.multi/attach-while-running.exp')
0 files changed, 0 insertions, 0 deletions