r216742 - Provide a BuryPointer for unique_ptrs.

[David Blaikie]

Author: dblaikie
Date: Fri Aug 29 11:53:14 2014
New Revision: 216742

URL: http://llvm.org/viewvc/llvm-project?rev=216742&view=rev
Log:
Provide a BuryPointer for unique_ptrs.

In theory, it'd be nice if we could move to a case where all buried
pointers were buried via unique_ptr to demonstrate that the program had
finished with the value (that we could really have cleanly deallocated
it) but instead chose to bury it.

I think the main reason that's not possible right now is the various
IntrusiveRefCntPtrs in the Frontend, sharing ownership for a variety of
compiler bits (see the various similar
"CompilerInstance::releaseAndLeak*" functions). I have yet to figure out
their correct ownership semantics - but perhaps, even if the
intrusiveness can be removed, the shared ownership may yet remain and
that would lead to a non-unique burying as is there today. (though we
could model that a little better - by passing in a shared_ptr, etc -
rather than needing the two step that's currently used in those other
releaseAndLeak* functions)

This might be a bit more robust if BuryPointer took the boolean:

BuryPointer(bool, unique_ptr<T>)

and the choice to bury was made internally - that way, even when
DisableFree was not set, the unique_ptr would still be null in the
caller and there'd be no chance of accidentally having a different
codepath where the value is used after burial in !DisableFree, but it
becomes null only in DisableFree, etc...

Modified:
    cfe/trunk/include/clang/Frontend/CompilerInstance.h
    cfe/trunk/include/clang/Frontend/Utils.h
    cfe/trunk/lib/CodeGen/BackendUtil.cpp
    cfe/trunk/lib/Frontend/CompilerInstance.cpp
    cfe/trunk/lib/FrontendTool/ExecuteCompilerInvocation.cpp

Modified: cfe/trunk/include/clang/Frontend/CompilerInstance.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Frontend/CompilerInstance.h?rev=216742&r1=216741&r2=216742&view=diff
==============================================================================
--- cfe/trunk/include/clang/Frontend/CompilerInstance.h (original)
+++ cfe/trunk/include/clang/Frontend/CompilerInstance.h Fri Aug 29 11:53:14 2014
@@ -461,7 +461,7 @@ public:
   }
 
   std::unique_ptr<Sema> takeSema();
-  void resetAndLeakSema() { BuryPointer(TheSema.release()); }
+  void resetAndLeakSema();
 
   /// }
   /// @name Module Management

Modified: cfe/trunk/include/clang/Frontend/Utils.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Frontend/Utils.h?rev=216742&r1=216741&r2=216742&view=diff
==============================================================================
--- cfe/trunk/include/clang/Frontend/Utils.h (original)
+++ cfe/trunk/include/clang/Frontend/Utils.h Fri Aug 29 11:53:14 2014
@@ -206,6 +206,9 @@ inline uint64_t getLastArgUInt64Value(co
 // global objects, but we don't want LeakDetectors to complain, so we bury them
 // in a globally visible array.
 void BuryPointer(const void *Ptr);
+template <typename T> void BuryPointer(std::unique_ptr<T> Ptr) {
+  BuryPointer(Ptr.release());
+}
 
 } // end namespace clang
 

Modified: cfe/trunk/lib/CodeGen/BackendUtil.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/BackendUtil.cpp?rev=216742&r1=216741&r2=216742&view=diff
==============================================================================
--- cfe/trunk/lib/CodeGen/BackendUtil.cpp (original)
+++ cfe/trunk/lib/CodeGen/BackendUtil.cpp Fri Aug 29 11:53:14 2014
@@ -122,7 +122,7 @@ public:
     delete PerModulePasses;
     delete PerFunctionPasses;
     if (CodeGenOpts.DisableFree)
-      BuryPointer(TM.release());
+      BuryPointer(std::move(TM));
   }
 
   std::unique_ptr<TargetMachine> TM;

Modified: cfe/trunk/lib/Frontend/CompilerInstance.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Frontend/CompilerInstance.cpp?rev=216742&r1=216741&r2=216742&view=diff
==============================================================================
--- cfe/trunk/lib/Frontend/CompilerInstance.cpp (original)
+++ cfe/trunk/lib/Frontend/CompilerInstance.cpp Fri Aug 29 11:53:14 2014
@@ -1605,3 +1605,4 @@ CompilerInstance::lookupMissingImports(S
 
   return false;
 }
+void CompilerInstance::resetAndLeakSema() { BuryPointer(takeSema()); }

Modified: cfe/trunk/lib/FrontendTool/ExecuteCompilerInvocation.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/FrontendTool/ExecuteCompilerInvocation.cpp?rev=216742&r1=216741&r2=216742&view=diff
==============================================================================
--- cfe/trunk/lib/FrontendTool/ExecuteCompilerInvocation.cpp (original)
+++ cfe/trunk/lib/FrontendTool/ExecuteCompilerInvocation.cpp Fri Aug 29 11:53:14 2014
@@ -221,6 +221,6 @@ bool clang::ExecuteCompilerInvocation(Co
     return false;
   bool Success = Clang->ExecuteAction(*Act);
   if (Clang->getFrontendOpts().DisableFree)
-    BuryPointer(Act.release());
+    BuryPointer(std::move(Act));
   return Success;
 }