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| author | Marek Polacek <polacek@redhat.com> | 2022-05-07 16:15:49 -0400 |
|---|---|---|
| committer | Marek Polacek <polacek@redhat.com> | 2022-05-18 10:34:30 -0400 |
| commit | 60fdce11dc9e5ddf671b07a3fc6ed70476860b22 (patch) | |
| tree | c8f625cb6000e14bf77d49ce48b2683660526034 /gcc/c-family | |
| parent | dfe38b8d5dbfe3dd5209aece4ce2f7a6b303a2f9 (diff) | |
| download | gcc-60fdce11dc9e5ddf671b07a3fc6ed70476860b22.zip gcc-60fdce11dc9e5ddf671b07a3fc6ed70476860b22.tar.gz gcc-60fdce11dc9e5ddf671b07a3fc6ed70476860b22.tar.bz2 | |
c, c++: -Wswitch warning on [[maybe_unused]] enumerator [PR105497]
This PR complains that we emit the "enumeration value not handled in
switch" warning even though the enumerator was marked with the
[[maybe_unused]] attribute.
I couldn't just check TREE_USED, because the enumerator could have been
used earlier in the function, which doesn't play well with the
c_do_switch_warnings warning. Instead, I had to check the attributes on
the CONST_DECL. This is easy since the TYPE_VALUES of an enum type are
now consistent between C and C++, both of which store the CONST_DECL in
its TREE_VALUE.
PR c++/105497
gcc/c-family/ChangeLog:
* c-warn.cc (c_do_switch_warnings): Don't warn about unhandled
enumerator when it was marked with attribute unused.
gcc/testsuite/ChangeLog:
* c-c++-common/Wswitch-1.c: New test.
* g++.dg/warn/Wswitch-4.C: New test.
Diffstat (limited to 'gcc/c-family')
| -rw-r--r-- | gcc/c-family/c-warn.cc | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/gcc/c-family/c-warn.cc b/gcc/c-family/c-warn.cc index cae8929..ea7335f 100644 --- a/gcc/c-family/c-warn.cc +++ b/gcc/c-family/c-warn.cc @@ -1738,8 +1738,8 @@ c_do_switch_warnings (splay_tree cases, location_t switch_location, for (chain = TYPE_VALUES (type); chain; chain = TREE_CHAIN (chain)) { tree value = TREE_VALUE (chain); - if (TREE_CODE (value) == CONST_DECL) - value = DECL_INITIAL (value); + tree attrs = DECL_ATTRIBUTES (value); + value = DECL_INITIAL (value); node = splay_tree_lookup (cases, (splay_tree_key) value); if (node) { @@ -1769,6 +1769,13 @@ c_do_switch_warnings (splay_tree cases, location_t switch_location, /* We've now determined that this enumerated literal isn't handled by the case labels of the switch statement. */ + /* Don't warn if the enumerator was marked as unused. We can't use + TREE_USED here: it could have been set on the enumerator if the + enumerator was used earlier. */ + if (lookup_attribute ("unused", attrs) + || lookup_attribute ("maybe_unused", attrs)) + continue; + /* If the switch expression is a constant, we only really care about whether that constant is handled by the switch. */ if (cond && tree_int_cst_compare (cond, value)) |