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| author | Nathan Sidwell <nathan@acm.org> | 2020-11-17 13:16:47 -0800 |
|---|---|---|
| committer | Nathan Sidwell <nathan@acm.org> | 2020-11-17 13:28:08 -0800 |
| commit | e0da4aed176a8de042a8482beb65499e29448556 (patch) | |
| tree | d98eed6396db0ba31b16418d0dedc9f884f1c2b6 | |
| parent | 066c89d1e1c509975a0e76be4279e2505084bd3b (diff) | |
| download | gcc-e0da4aed176a8de042a8482beb65499e29448556.zip gcc-e0da4aed176a8de042a8482beb65499e29448556.tar.gz gcc-e0da4aed176a8de042a8482beb65499e29448556.tar.bz2 | |
c++: duplicate block-scope extern [PR 97877]
We ICED with a duplicated block-scope extern, as duplicate_decls was
dropping the decl_lang_specific of olddecl. Simplys adding
appropriate retrofitting and copying turned out to be insufficient
because you can get a block-scope using decl also matching the extern.
The latter seems a little suspicious and I have asked CWG for advice.
While there robustified the assert about releasing olddecls'
lang-specific -- if it had one, the new decl better have one.
PR c++/97877
gcc/cp/
* decl.c (duplicate_decls): Deal with duplicated DECL_LOCAL_DECL_P
decls. Extend decl_lang_specific checking assert.
gcc/testsuite/
* g++.dg/lookup/pr97877.C: New.
| -rw-r--r-- | gcc/cp/decl.c | 19 | ||||
| -rw-r--r-- | gcc/testsuite/g++.dg/lookup/pr97877.C | 8 |
2 files changed, 25 insertions, 2 deletions
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c index 89bae06..d90e984 100644 --- a/gcc/cp/decl.c +++ b/gcc/cp/decl.c @@ -2452,6 +2452,20 @@ duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden) if (! DECL_COMDAT (olddecl)) DECL_COMDAT (newdecl) = 0; + if (VAR_OR_FUNCTION_DECL_P (newdecl) && DECL_LOCAL_DECL_P (newdecl)) + { + if (!DECL_LOCAL_DECL_P (olddecl)) + /* This can happen if olddecl was brought in from the + enclosing namespace via a using-decl. The new decl is + then not a block-scope extern at all. */ + DECL_LOCAL_DECL_P (newdecl) = false; + else + { + retrofit_lang_decl (newdecl); + DECL_LOCAL_DECL_ALIAS (newdecl) = DECL_LOCAL_DECL_ALIAS (olddecl); + } + } + new_template_info = NULL_TREE; if (DECL_LANG_SPECIFIC (newdecl) && DECL_LANG_SPECIFIC (olddecl)) { @@ -2735,8 +2749,9 @@ duplicate_decls (tree newdecl, tree olddecl, bool hiding, bool was_hidden) with that from NEWDECL below. */ if (DECL_LANG_SPECIFIC (olddecl)) { - gcc_assert (DECL_LANG_SPECIFIC (olddecl) - != DECL_LANG_SPECIFIC (newdecl)); + gcc_checking_assert (DECL_LANG_SPECIFIC (newdecl) + && (DECL_LANG_SPECIFIC (olddecl) + != DECL_LANG_SPECIFIC (newdecl))); ggc_free (DECL_LANG_SPECIFIC (olddecl)); } diff --git a/gcc/testsuite/g++.dg/lookup/pr97877.C b/gcc/testsuite/g++.dg/lookup/pr97877.C new file mode 100644 index 0000000..294edd2 --- /dev/null +++ b/gcc/testsuite/g++.dg/lookup/pr97877.C @@ -0,0 +1,8 @@ +// PR 97877, duplicate decls smashed decl_lang_specific + +void f () +{ + extern int a; + extern int a; + a = 2; +} |