[llvm] r215793 - [PowerPC] Darwin byval arguments are not immutable

[Hal Finkel]

Author: hfinkel
Date: Fri Aug 15 19:16:29 2014
New Revision: 215793

URL: http://llvm.org/viewvc/llvm-project?rev=215793&view=rev
Log:
[PowerPC] Darwin byval arguments are not immutable

On PPC/Darwin, byval arguments occur at fixed stack offsets in the callee's
frame, but are not immutable -- the pointer value is directly available to the
higher-level code as the address of the argument, and the value of the byval
argument can be modified at the IR level.

This is necessary, but not sufficient, to fix PR20280. When PR20280 is fixed in
a follow-up commit, its test case will cover this change.

Modified:
    llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp

Modified: llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp?rev=215793&r1=215792&r2=215793&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp Fri Aug 15 19:16:29 2014
@@ -3066,7 +3066,7 @@ PPCTargetLowering::LowerFormalArguments_
         CurArgOffset = CurArgOffset + (4 - ObjSize);
       }
       // The value of the object is its address.
-      int FI = MFI->CreateFixedObject(ObjSize, CurArgOffset, true);
+      int FI = MFI->CreateFixedObject(ObjSize, CurArgOffset, false);
       SDValue FIN = DAG.getFrameIndex(FI, PtrVT);
       InVals.push_back(FIN);
       if (ObjSize==1 || ObjSize==2) {