Aggressively prune the DFS when inserting phi-defs.

[oota-llvm.git] / include / llvm / Target / TargetFrameInfo.h

diff --git a/include/llvm/Target/TargetFrameInfo.h b/include/llvm/Target/TargetFrameInfo.h
index 3e26b9dd01bea6112c778d529388b30fdd4a1263..975d15659c15f1c6730036ce744262ab5dad0625 100644 (file)
--- a/include/llvm/Target/TargetFrameInfo.h
+++ b/include/llvm/Target/TargetFrameInfo.h
@@ -31,13 +31,22 @@ public:
     StackGrowsUp,        // Adding to the stack increases the stack address
     StackGrowsDown       // Adding to the stack decreases the stack address
   };
+
+  // Maps a callee saved register to a stack slot with a fixed offset.
+  struct SpillSlot {
+    unsigned Reg;
+    int Offset; // Offset relative to stack pointer on function entry.
+  };
 private:
   StackDirection StackDir;
   unsigned StackAlignment;
+  unsigned TransientStackAlignment;
   int LocalAreaOffset;
 public:
-  TargetFrameInfo(StackDirection D, unsigned StackAl, int LAO)
-    : StackDir(D), StackAlignment(StackAl), LocalAreaOffset(LAO) {}
+  TargetFrameInfo(StackDirection D, unsigned StackAl, int LAO,
+                  unsigned TransAl = 1)
+    : StackDir(D), StackAlignment(StackAl), TransientStackAlignment(TransAl),
+      LocalAreaOffset(LAO) {}
 
   virtual ~TargetFrameInfo();
 
@@ -48,12 +57,20 @@ public:
   ///
   StackDirection getStackGrowthDirection() const { return StackDir; }
 
-  /// getStackAlignment - This method returns the number of bytes that the stack
-  /// pointer must be aligned to.  Typically, this is the largest alignment for
-  /// any data object in the target.
+  /// getStackAlignment - This method returns the number of bytes to which the
+  /// stack pointer must be aligned on entry to a function.  Typically, this
+  /// is the largest alignment for any data object in the target.
   ///
   unsigned getStackAlignment() const { return StackAlignment; }
 
+  /// getTransientStackAlignment - This method returns the number of bytes to
+  /// which the stack pointer must be aligned at all times, even between
+  /// calls.
+  ///
+  unsigned getTransientStackAlignment() const {
+    return TransientStackAlignment;
+  }
+
   /// getOffsetOfLocalArea - This method returns the offset of the local area
   /// from the stack pointer on entrance to a function.
   ///
@@ -65,10 +82,10 @@ public:
   ///
   /// Each entry in this array contains a <register,offset> pair, indicating the
   /// fixed offset from the incoming stack pointer that each register should be
-  /// spilled at.  If a register is not listed here, the code generator is
+  /// spilled at. If a register is not listed here, the code generator is
   /// allowed to spill it anywhere it chooses.
   ///
-  virtual const std::pair<unsigned, int> *
+  virtual const SpillSlot *
   getCalleeSavedSpillSlots(unsigned &NumEntries) const {
     NumEntries = 0;
     return 0;