Teach gcroot how to handle dynamically realigned frames

[oota-llvm.git] / lib / CodeGen / GCRootLowering.cpp

diff --git a/lib/CodeGen/GCRootLowering.cpp b/lib/CodeGen/GCRootLowering.cpp
index 9d38e4cad13087fce1f7c3fef0180626d2c77278..ac351656a4ae019dfd2182dacd5740888aa57393 100644 (file)
--- a/lib/CodeGen/GCRootLowering.cpp
+++ b/lib/CodeGen/GCRootLowering.cpp
@@ -332,19 +332,22 @@ bool GCMachineCodeAnalysis::runOnMachineFunction(MachineFunction &MF) {
     return false;
 
   FI = &getAnalysis<GCModuleInfo>().getFunctionInfo(*MF.getFunction());
-  if (!FI->getStrategy().needsSafePoints())
-    return false;
-
   MMI = &getAnalysis<MachineModuleInfo>();
   TII = MF.getSubtarget().getInstrInfo();
 
-  // Find the size of the stack frame.
-  FI->setFrameSize(MF.getFrameInfo()->getStackSize());
+  // Find the size of the stack frame.  There may be no correct static frame
+  // size, we use UINT64_MAX to represent this.
+  const MachineFrameInfo *MFI = MF.getFrameInfo();
+  const TargetRegisterInfo *RegInfo = MF.getSubtarget().getRegisterInfo();
+  const bool DynamicFrameSize = MFI->hasVarSizedObjects() ||
+    RegInfo->needsStackRealignment(MF);
+  FI->setFrameSize(DynamicFrameSize ? UINT64_MAX : MFI->getStackSize());
 
   // Find all safe points.
-  FindSafePoints(MF);
+  if (FI->getStrategy().needsSafePoints())
+    FindSafePoints(MF);
 
-  // Find the stack offsets for all roots.
+  // Find the concrete stack offsets for all roots (stack slots)
   FindStackOffsets(MF);
 
   return false;