[PATCH] D27683: Prepare PrettyStackTrace for LLDB adoption

[Nico Weber via Phabricator via cfe-commits]

thakis added inline comments.
Herald added subscribers: llvm-commits, kristina.
Herald added a project: LLVM.


================
Comment at: llvm/trunk/lib/Support/PrettyStackTrace.cpp:93
+extern "C" const char *__crashreporter_info__
+    __attribute__((visibility("hidden"))) = 0;
 asm(".desc ___crashreporter_info__, 0x10");
----------------
As far as I can tell, making this a hidden symbol makes the `.desc ___crashreporter_info__, 0x10` (ie REFERENCED_DYNAMICALLY) not have any effect:

```
% cat crashref.cc
extern "C" const char *__crashreporter_info__  __attribute__((visibility("hidden"))) = 0;
asm(".desc ___crashreporter_info__, 0x10");
int main() {}
% clang crashref.cc
% nm -m a.out
0000000100004000 (__DATA,__common) non-external (was a private external) ___crashreporter_info__
0000000100000000 (__TEXT,__text) [referenced dynamically] external __mh_execute_header
0000000100003fb0 (__TEXT,__text) external _main
                 (undefined) external dyld_stub_binder (from libSystem)
% strip -r a.out
% nm -m a.out
0000000100000000 (__TEXT,__text) [referenced dynamically] external __mh_execute_header
```

It does have an effect without it:
```
% cat crashref.cc
extern "C" const char *__crashreporter_info__ = 0;
asm(".desc ___crashreporter_info__, 0x10");
int main() {}
% clang crashref.cc
% nm -m a.out
0000000100004000 (__DATA,__common) [referenced dynamically] external ___crashreporter_info__
0000000100000000 (__TEXT,__text) [referenced dynamically] external __mh_execute_header
0000000100003fb0 (__TEXT,__text) external _main
                 (undefined) external dyld_stub_binder (from libSystem)
% strip -r a.out
% nm -m a.out
0000000100004000 (__DATA,__common) [referenced dynamically] external ___crashreporter_info__
0000000100000000 (__TEXT,__text) [referenced dynamically] external __mh_execute_header
```

Is that intentional? Should we just remove the `.desc` line?


Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D27683/new/

https://reviews.llvm.org/D27683