[llvm] r187302 - Fix yet another memory leak found by the vg-leak bot. Folks (including

Chandler Carruth chandlerc at gmail.com
Sat Jul 27 04:23:08 PDT 2013


Author: chandlerc
Date: Sat Jul 27 06:23:08 2013
New Revision: 187302

URL: http://llvm.org/viewvc/llvm-project?rev=187302&view=rev
Log:
Fix yet another memory leak found by the vg-leak bot. Folks (including
me) should start watching this bot more as its catching lots of bugs.

The fix here is to not construct the global if we aren't going to need
it. That's cheaper anyways, and globals have highly predictable types in
practice. I've added an assert to catch skew between our manual testing
of the type and the actual type just for paranoia's sake.

Note that this pattern is actually fine in most globals because when you
build a global with a module it automatically is moved to be owned by
that module. But here, we're in isel and don't really want to do that.
The solution of not creating a global is simpler anyways.

Modified:
    llvm/trunk/lib/Target/ARM/ARMFastISel.cpp

Modified: llvm/trunk/lib/Target/ARM/ARMFastISel.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMFastISel.cpp?rev=187302&r1=187301&r2=187302&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMFastISel.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMFastISel.cpp Sat Jul 27 06:23:08 2013
@@ -2185,10 +2185,14 @@ unsigned ARMFastISel::ARMSelectCallOp(bo
 }
 
 unsigned ARMFastISel::getLibcallReg(const Twine &Name) {
+  // Manually compute the global's type to avoid building it when unnecessary.
+  Type *GVTy = Type::getInt32PtrTy(*Context, /*AS=*/0);
+  EVT LCREVT = TLI.getValueType(GVTy);
+  if (!LCREVT.isSimple()) return 0;
+
   GlobalValue *GV = new GlobalVariable(Type::getInt32Ty(*Context), false,
                                        GlobalValue::ExternalLinkage, 0, Name);
-  EVT LCREVT = TLI.getValueType(GV->getType());
-  if (!LCREVT.isSimple()) return 0;
+  assert(GV->getType() == GVTy && "We miscomputed the type for the global!");
   return ARMMaterializeGV(GV, LCREVT.getSimpleVT());
 }
 





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