[gdb/symtab] Prefer def over decl (inter-CU case)
When running test-case gdb.threads/tls.exp with target board -readnow, we
have:
...
(gdb) print a_thread_local^M
Cannot find thread-local storage for process 0, executable file tls/tls:^M
Cannot find thread-local variables on this target^M
(gdb) FAIL: gdb.threads/tls.exp: print a_thread_local
...
while with native we have:
...
(gdb) print a_thread_local^M
Cannot read `a_thread_local' without registers^M
(gdb) PASS: gdb.threads/tls.exp: print a_thread_local
...
The difference in behaviour can be explained as follows. Without -readnow, we
have two a_thread_locals, the def and the decl, each in a different CU:
...
$ gdb -batch outputs/gdb.threads/tls/tls \
-ex "maint expand-symtabs" \
-ex "print a_thread_local" \
-ex "maint print symbols" \
| grep "a_thread_local;"
Cannot read `a_thread_local' without registers
int a_thread_local; computed at runtime
int a_thread_local; unresolved
...
and with -readnow, we have the opposite order:
...
$ gdb -readnow -batch outputs/gdb.threads/tls/tls \
-ex "maint expand-symtabs" \
-ex "print a_thread_local" \
-ex "maint print symbols" \
| grep "a_thread_local;"
Cannot find thread-local storage for process 0, executable file tls/tls:
Cannot find thread-local variables on this target
int a_thread_local; unresolved
int a_thread_local; computed at runtime
...
Fix the FAIL by preferring the def over the decl (something we already do
intra-CU since the fix for PR24971, commit 93e55f0a03 "[gdb/symtab] Prefer var
def over decl").
Build and reg-tested on x86_64-linux.
gdb/ChangeLog:
2020-04-23 Tom de Vries <tdevries@suse.de>
PR symtab/25807
* block.c (best_symbol, better_symbol): Promote to external.
* block.h (best_symbol, better_symbol): Declare.
* symtab.c (lookup_symbol_in_objfile_symtabs): Prefer def over
decl.
gdb/testsuite/ChangeLog:
2020-04-23 Tom de Vries <tdevries@suse.de>
* gdb.base/decl-before-def-decl.c: New test.
* gdb.base/decl-before-def-def.c: New test.
* gdb.base/decl-before-def.exp: New file.
8 files changed
