[PATCH] [Sanitizer RT] Put the module name string ownership in Symbolizer in order

[Kostya Serebryany]

Ok, let's go this way...


================
Comment at: sanitizer_symbolizer.h:90
@@ -87,1 +89,3 @@
+  // module.  It is safe to store and compare them as pointers as long as the
+  // Symbolizer owning these strings is alive.
   bool GetModuleNameAndOffsetForPC(uptr pc, const char **module_name,
----------------
Can you modify the comments (and logic) by removing "as long as .. "
These names should be just live forever, independent of anything. 

================
Comment at: sanitizer_symbolizer.h:120
@@ +119,3 @@
+  // corresponding module might get unloaded later.  To prevent use-after-free
+  // race conditions, create Symbolizer-owned copies of the strings that we can
+  // safely return.
----------------
Why race conditions? 
This may happen w/o any threads, right? 

================
Comment at: sanitizer_symbolizer.h:125
@@ +124,3 @@
+    ModuleNameOwner() : storage_(1000), last_match_(nullptr) {}
+    const char *GetOwnedCopy(const char *str);
+
----------------
add a comment explaining thread-(un) safety and which lock should be held.

http://reviews.llvm.org/D8666

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