Add support for dynamic stack realignment in the presence of dynamic allocas on

X86.
rdar://11496434


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158087 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/Target/X86/X86RegisterInfo.h b/lib/Target/X86/X86RegisterInfo.h
index ee69842..1bc32cb 100644
--- a/lib/Target/X86/X86RegisterInfo.h
+++ b/lib/Target/X86/X86RegisterInfo.h
@@ -50,6 +50,11 @@ private:
   ///
   unsigned FramePtr;
 
+  /// BasePtr - X86 physical register used as a base ptr in complex stack
+  /// frames. I.e., when we need a 3rd base, not just SP and FP, due to
+  /// variable size stack objects.
+  unsigned BasePtr;
+
 public:
   X86RegisterInfo(X86TargetMachine &tm, const TargetInstrInfo &tii);
 
@@ -106,6 +111,8 @@ public:
   /// register scavenger to determine what registers are free.
   BitVector getReservedRegs(const MachineFunction &MF) const;
 
+  bool hasBasePointer(const MachineFunction &MF) const;
+
   bool canRealignStack(const MachineFunction &MF) const;
 
   bool needsStackRealignment(const MachineFunction &MF) const;
@@ -123,6 +130,7 @@ public:
   // Debug information queries.
   unsigned getFrameRegister(const MachineFunction &MF) const;
   unsigned getStackRegister() const { return StackPtr; }
+  unsigned getBaseRegister() const { return BasePtr; }
   // FIXME: Move to FrameInfok
   unsigned getSlotSize() const { return SlotSize; }