Move the FunctionLoweringInfo class and some related utility functions out
of SelectionDAGBuild.h/cpp into its own files, to help separate
general lowering logic from SelectionDAG-specific lowering logic.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89667 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.h b/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.h
new file mode 100644
index 0000000..09fc23f
--- /dev/null
+++ b/lib/CodeGen/SelectionDAG/FunctionLoweringInfo.h
@@ -0,0 +1,137 @@
+//===-- FunctionLoweringInfo.h - Lower functions from LLVM IR to CodeGen --===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This implements routines for translating functions from LLVM IR into
+// Machine IR.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef FUNCTIONLOWERINGINFO_H
+#define FUNCTIONLOWERINGINFO_H
+
+#include "llvm/ADT/APInt.h"
+#include "llvm/ADT/DenseMap.h"
+#ifndef NDEBUG
+#include "llvm/ADT/SmallSet.h"
+#endif
+#include "llvm/CodeGen/ValueTypes.h"
+#include <vector>
+
+namespace llvm {
+
+class AllocaInst;
+class BasicBlock;
+class Function;
+class Instruction;
+class MachineBasicBlock;
+class MachineFunction;
+class MachineRegisterInfo;
+class TargetLowering;
+class Value;
+
+//===--------------------------------------------------------------------===//
+/// FunctionLoweringInfo - This contains information that is global to a
+/// function that is used when lowering a region of the function.
+///
+class FunctionLoweringInfo {
+public:
+  TargetLowering &TLI;
+  Function *Fn;
+  MachineFunction *MF;
+  MachineRegisterInfo *RegInfo;
+
+  /// CanLowerReturn - true iff the function's return value can be lowered to
+  /// registers.
+  bool CanLowerReturn;
+
+  /// DemoteRegister - if CanLowerReturn is false, DemoteRegister is a vreg
+  /// allocated to hold a pointer to the hidden sret parameter.
+  unsigned DemoteRegister;
+
+  explicit FunctionLoweringInfo(TargetLowering &TLI);
+
+  /// set - Initialize this FunctionLoweringInfo with the given Function
+  /// and its associated MachineFunction.
+  ///
+  void set(Function &Fn, MachineFunction &MF, bool EnableFastISel);
+
+  /// MBBMap - A mapping from LLVM basic blocks to their machine code entry.
+  DenseMap<const BasicBlock*, MachineBasicBlock *> MBBMap;
+
+  /// ValueMap - Since we emit code for the function a basic block at a time,
+  /// we must remember which virtual registers hold the values for
+  /// cross-basic-block values.
+  DenseMap<const Value*, unsigned> ValueMap;
+
+  /// StaticAllocaMap - Keep track of frame indices for fixed sized allocas in
+  /// the entry block.  This allows the allocas to be efficiently referenced
+  /// anywhere in the function.
+  DenseMap<const AllocaInst*, int> StaticAllocaMap;
+
+#ifndef NDEBUG
+  SmallSet<Instruction*, 8> CatchInfoLost;
+  SmallSet<Instruction*, 8> CatchInfoFound;
+#endif
+
+  unsigned MakeReg(EVT VT);
+  
+  /// isExportedInst - Return true if the specified value is an instruction
+  /// exported from its block.
+  bool isExportedInst(const Value *V) {
+    return ValueMap.count(V);
+  }
+
+  unsigned CreateRegForValue(const Value *V);
+  
+  unsigned InitializeRegForValue(const Value *V) {
+    unsigned &R = ValueMap[V];
+    assert(R == 0 && "Already initialized this value register!");
+    return R = CreateRegForValue(V);
+  }
+  
+  struct LiveOutInfo {
+    unsigned NumSignBits;
+    APInt KnownOne, KnownZero;
+    LiveOutInfo() : NumSignBits(0), KnownOne(1, 0), KnownZero(1, 0) {}
+  };
+  
+  /// LiveOutRegInfo - Information about live out vregs, indexed by their
+  /// register number offset by 'FirstVirtualRegister'.
+  std::vector<LiveOutInfo> LiveOutRegInfo;
+
+  /// clear - Clear out all the function-specific state. This returns this
+  /// FunctionLoweringInfo to an empty state, ready to be used for a
+  /// different function.
+  void clear();
+};
+
+/// ComputeLinearIndex - Given an LLVM IR aggregate type and a sequence
+/// of insertvalue or extractvalue indices that identify a member, return
+/// the linearized index of the start of the member.
+///
+unsigned ComputeLinearIndex(const TargetLowering &TLI, const Type *Ty,
+                            const unsigned *Indices,
+                            const unsigned *IndicesEnd,
+                            unsigned CurIndex = 0);
+
+/// ComputeValueVTs - Given an LLVM IR type, compute a sequence of
+/// EVTs that represent all the individual underlying
+/// non-aggregate types that comprise it.
+///
+/// If Offsets is non-null, it points to a vector to be filled in
+/// with the in-memory offsets of each of the individual values.
+///
+void ComputeValueVTs(const TargetLowering &TLI, const Type *Ty,
+                     SmallVectorImpl<EVT> &ValueVTs,
+                     SmallVectorImpl<uint64_t> *Offsets = 0,
+                     uint64_t StartingOffset = 0);
+
+} // end namespace llvm
+
+#endif