Import LLVM, at r72732.

1 files changed, 411 insertions, 0 deletions

diff --git a/include/llvm/CodeGen/MachineFrameInfo.h b/include/llvm/CodeGen/MachineFrameInfo.h
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+//===-- CodeGen/MachineFrameInfo.h - Abstract Stack Frame Rep. --*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// The file defines the MachineFrameInfo class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CODEGEN_MACHINEFRAMEINFO_H
+#define LLVM_CODEGEN_MACHINEFRAMEINFO_H
+
+#include "llvm/Support/DataTypes.h"
+#include <cassert>
+#include <iosfwd>
+#include <vector>
+
+namespace llvm {
+class TargetData;
+class TargetRegisterClass;
+class Type;
+class MachineModuleInfo;
+class MachineFunction;
+class TargetFrameInfo;
+
+/// The CalleeSavedInfo class tracks the information need to locate where a
+/// callee saved register in the current frame.  
+class CalleeSavedInfo {
+
+private:
+  unsigned Reg;
+  const TargetRegisterClass *RegClass;
+  int FrameIdx;
+  
+public:
+  CalleeSavedInfo(unsigned R, const TargetRegisterClass *RC, int FI = 0)
+  : Reg(R)
+  , RegClass(RC)
+  , FrameIdx(FI)
+  {}
+  
+  // Accessors.
+  unsigned getReg()                        const { return Reg; }
+  const TargetRegisterClass *getRegClass() const { return RegClass; }
+  int getFrameIdx()                        const { return FrameIdx; }
+  void setFrameIdx(int FI)                       { FrameIdx = FI; }
+};
+
+/// The MachineFrameInfo class represents an abstract stack frame until
+/// prolog/epilog code is inserted.  This class is key to allowing stack frame
+/// representation optimizations, such as frame pointer elimination.  It also
+/// allows more mundane (but still important) optimizations, such as reordering
+/// of abstract objects on the stack frame.
+///
+/// To support this, the class assigns unique integer identifiers to stack
+/// objects requested clients.  These identifiers are negative integers for
+/// fixed stack objects (such as arguments passed on the stack) or nonnegative
+/// for objects that may be reordered.  Instructions which refer to stack
+/// objects use a special MO_FrameIndex operand to represent these frame
+/// indexes.
+///
+/// Because this class keeps track of all references to the stack frame, it
+/// knows when a variable sized object is allocated on the stack.  This is the
+/// sole condition which prevents frame pointer elimination, which is an
+/// important optimization on register-poor architectures.  Because original
+/// variable sized alloca's in the source program are the only source of
+/// variable sized stack objects, it is safe to decide whether there will be
+/// any variable sized objects before all stack objects are known (for
+/// example, register allocator spill code never needs variable sized
+/// objects).
+///
+/// When prolog/epilog code emission is performed, the final stack frame is
+/// built and the machine instructions are modified to refer to the actual
+/// stack offsets of the object, eliminating all MO_FrameIndex operands from
+/// the program.
+///
+/// @brief Abstract Stack Frame Information
+class MachineFrameInfo {
+
+  // StackObject - Represent a single object allocated on the stack.
+  struct StackObject {
+    // The size of this object on the stack. 0 means a variable sized object,
+    // ~0ULL means a dead object.
+    uint64_t Size;
+
+    // Alignment - The required alignment of this stack slot.
+    unsigned Alignment;
+
+    // isImmutable - If true, the value of the stack object is set before
+    // entering the function and is not modified inside the function. By
+    // default, fixed objects are immutable unless marked otherwise.
+    bool isImmutable;
+
+    // SPOffset - The offset of this object from the stack pointer on entry to
+    // the function.  This field has no meaning for a variable sized element.
+    int64_t SPOffset;
+    
+    StackObject(uint64_t Sz, unsigned Al, int64_t SP = 0, bool IM = false)
+      : Size(Sz), Alignment(Al), isImmutable(IM), SPOffset(SP) {}
+  };
+
+  /// Objects - The list of stack objects allocated...
+  ///
+  std::vector<StackObject> Objects;
+
+  /// NumFixedObjects - This contains the number of fixed objects contained on
+  /// the stack.  Because fixed objects are stored at a negative index in the
+  /// Objects list, this is also the index to the 0th object in the list.
+  ///
+  unsigned NumFixedObjects;
+
+  /// HasVarSizedObjects - This boolean keeps track of whether any variable
+  /// sized objects have been allocated yet.
+  ///
+  bool HasVarSizedObjects;
+
+  /// FrameAddressTaken - This boolean keeps track of whether there is a call
+  /// to builtin \@llvm.frameaddress.
+  bool FrameAddressTaken;
+
+  /// StackSize - The prolog/epilog code inserter calculates the final stack
+  /// offsets for all of the fixed size objects, updating the Objects list
+  /// above.  It then updates StackSize to contain the number of bytes that need
+  /// to be allocated on entry to the function.
+  ///
+  uint64_t StackSize;
+  
+  /// OffsetAdjustment - The amount that a frame offset needs to be adjusted to
+  /// have the actual offset from the stack/frame pointer.  The calculation is 
+  /// MFI->getObjectOffset(Index) + StackSize - TFI.getOffsetOfLocalArea() +
+  /// OffsetAdjustment.  If OffsetAdjustment is zero (default) then offsets are
+  /// away from TOS. If OffsetAdjustment == StackSize then offsets are toward
+  /// TOS.
+  int OffsetAdjustment;
+  
+  /// MaxAlignment - The prolog/epilog code inserter may process objects 
+  /// that require greater alignment than the default alignment the target
+  /// provides. To handle this, MaxAlignment is set to the maximum alignment 
+  /// needed by the objects on the current frame.  If this is greater than the
+  /// native alignment maintained by the compiler, dynamic alignment code will
+  /// be needed.
+  ///
+  unsigned MaxAlignment;
+
+  /// HasCalls - Set to true if this function has any function calls.  This is
+  /// only valid during and after prolog/epilog code insertion.
+  bool HasCalls;
+
+  /// StackProtectorIdx - The frame index for the stack protector.
+  int StackProtectorIdx;
+
+  /// MaxCallFrameSize - This contains the size of the largest call frame if the
+  /// target uses frame setup/destroy pseudo instructions (as defined in the
+  /// TargetFrameInfo class).  This information is important for frame pointer
+  /// elimination.  If is only valid during and after prolog/epilog code
+  /// insertion.
+  ///
+  unsigned MaxCallFrameSize;
+  
+  /// CSInfo - The prolog/epilog code inserter fills in this vector with each
+  /// callee saved register saved in the frame.  Beyond its use by the prolog/
+  /// epilog code inserter, this data used for debug info and exception
+  /// handling.
+  std::vector<CalleeSavedInfo> CSInfo;
+  
+  /// MMI - This field is set (via setMachineModuleInfo) by a module info
+  /// consumer (ex. DwarfWriter) to indicate that frame layout information
+  /// should be acquired.  Typically, it's the responsibility of the target's
+  /// TargetRegisterInfo prologue/epilogue emitting code to inform
+  /// MachineModuleInfo of frame layouts.
+  MachineModuleInfo *MMI;
+  
+  /// TargetFrameInfo - Target information about frame layout.
+  ///
+  const TargetFrameInfo &TFI;
+public:
+  explicit MachineFrameInfo(const TargetFrameInfo &tfi) : TFI(tfi) {
+    StackSize = NumFixedObjects = OffsetAdjustment = MaxAlignment = 0;
+    HasVarSizedObjects = false;
+    FrameAddressTaken = false;
+    HasCalls = false;
+    StackProtectorIdx = -1;
+    MaxCallFrameSize = 0;
+    MMI = 0;
+  }
+
+  /// hasStackObjects - Return true if there are any stack objects in this
+  /// function.
+  ///
+  bool hasStackObjects() const { return !Objects.empty(); }
+
+  /// hasVarSizedObjects - This method may be called any time after instruction
+  /// selection is complete to determine if the stack frame for this function
+  /// contains any variable sized objects.
+  ///
+  bool hasVarSizedObjects() const { return HasVarSizedObjects; }
+
+  /// getStackProtectorIndex/setStackProtectorIndex - Return the index for the
+  /// stack protector object.
+  ///
+  int getStackProtectorIndex() const { return StackProtectorIdx; }
+  void setStackProtectorIndex(int I) { StackProtectorIdx = I; }
+
+  /// isFrameAddressTaken - This method may be called any time after instruction
+  /// selection is complete to determine if there is a call to
+  /// \@llvm.frameaddress in this function.
+  bool isFrameAddressTaken() const { return FrameAddressTaken; }
+  void setFrameAddressIsTaken(bool T) { FrameAddressTaken = T; }
+
+  /// getObjectIndexBegin - Return the minimum frame object index.
+  ///
+  int getObjectIndexBegin() const { return -NumFixedObjects; }
+
+  /// getObjectIndexEnd - Return one past the maximum frame object index.
+  ///
+  int getObjectIndexEnd() const { return (int)Objects.size()-NumFixedObjects; }
+
+  /// getNumFixedObjects() - Return the number of fixed objects.
+  unsigned getNumFixedObjects() const { return NumFixedObjects; }
+
+  /// getNumObjects() - Return the number of objects.
+  ///
+  unsigned getNumObjects() const { return Objects.size(); }
+
+  /// getObjectSize - Return the size of the specified object.
+  ///
+  int64_t getObjectSize(int ObjectIdx) const {
+    assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
+           "Invalid Object Idx!");
+    return Objects[ObjectIdx+NumFixedObjects].Size;
+  }
+
+  /// setObjectSize - Change the size of the specified stack object.
+  void setObjectSize(int ObjectIdx, int64_t Size) {
+    assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
+           "Invalid Object Idx!");
+    Objects[ObjectIdx+NumFixedObjects].Size = Size;
+  }
+
+  /// getObjectAlignment - Return the alignment of the specified stack object.
+  unsigned getObjectAlignment(int ObjectIdx) const {
+    assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
+           "Invalid Object Idx!");
+    return Objects[ObjectIdx+NumFixedObjects].Alignment;
+  }
+
+  /// setObjectAlignment - Change the alignment of the specified stack object.
+  void setObjectAlignment(int ObjectIdx, unsigned Align) {
+    assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
+           "Invalid Object Idx!");
+    Objects[ObjectIdx+NumFixedObjects].Alignment = Align;
+  }
+
+  /// getObjectOffset - Return the assigned stack offset of the specified object
+  /// from the incoming stack pointer.
+  ///
+  int64_t getObjectOffset(int ObjectIdx) const {
+    assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
+           "Invalid Object Idx!");
+    assert(!isDeadObjectIndex(ObjectIdx) &&
+           "Getting frame offset for a dead object?");
+    return Objects[ObjectIdx+NumFixedObjects].SPOffset;
+  }
+
+  /// setObjectOffset - Set the stack frame offset of the specified object.  The
+  /// offset is relative to the stack pointer on entry to the function.
+  ///
+  void setObjectOffset(int ObjectIdx, int64_t SPOffset) {
+    assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
+           "Invalid Object Idx!");
+    assert(!isDeadObjectIndex(ObjectIdx) &&
+           "Setting frame offset for a dead object?");
+    Objects[ObjectIdx+NumFixedObjects].SPOffset = SPOffset;
+  }
+
+  /// getStackSize - Return the number of bytes that must be allocated to hold
+  /// all of the fixed size frame objects.  This is only valid after
+  /// Prolog/Epilog code insertion has finalized the stack frame layout.
+  ///
+  uint64_t getStackSize() const { return StackSize; }
+
+  /// setStackSize - Set the size of the stack...
+  ///
+  void setStackSize(uint64_t Size) { StackSize = Size; }
+  
+  /// getOffsetAdjustment - Return the correction for frame offsets.
+  ///
+  int getOffsetAdjustment() const { return OffsetAdjustment; }
+  
+  /// setOffsetAdjustment - Set the correction for frame offsets.
+  ///
+  void setOffsetAdjustment(int Adj) { OffsetAdjustment = Adj; }
+
+  /// getMaxAlignment - Return the alignment in bytes that this function must be 
+  /// aligned to, which is greater than the default stack alignment provided by 
+  /// the target.
+  ///
+  unsigned getMaxAlignment() const { return MaxAlignment; }
+  
+  /// setMaxAlignment - Set the preferred alignment.
+  ///
+  void setMaxAlignment(unsigned Align) { MaxAlignment = Align; }
+  
+  /// hasCalls - Return true if the current function has no function calls.
+  /// This is only valid during or after prolog/epilog code emission.
+  ///
+  bool hasCalls() const { return HasCalls; }
+  void setHasCalls(bool V) { HasCalls = V; }
+
+  /// getMaxCallFrameSize - Return the maximum size of a call frame that must be
+  /// allocated for an outgoing function call.  This is only available if
+  /// CallFrameSetup/Destroy pseudo instructions are used by the target, and
+  /// then only during or after prolog/epilog code insertion.
+  ///
+  unsigned getMaxCallFrameSize() const { return MaxCallFrameSize; }
+  void setMaxCallFrameSize(unsigned S) { MaxCallFrameSize = S; }
+
+  /// CreateFixedObject - Create a new object at a fixed location on the stack.
+  /// All fixed objects should be created before other objects are created for
+  /// efficiency. By default, fixed objects are immutable. This returns an
+  /// index with a negative value.
+  ///
+  int CreateFixedObject(uint64_t Size, int64_t SPOffset,
+                        bool Immutable = true);
+  
+  
+  /// isFixedObjectIndex - Returns true if the specified index corresponds to a
+  /// fixed stack object.
+  bool isFixedObjectIndex(int ObjectIdx) const {
+    return ObjectIdx < 0 && (ObjectIdx >= -(int)NumFixedObjects);
+  }
+
+  /// isImmutableObjectIndex - Returns true if the specified index corresponds
+  /// to an immutable object.
+  bool isImmutableObjectIndex(int ObjectIdx) const {
+    assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
+           "Invalid Object Idx!");
+    return Objects[ObjectIdx+NumFixedObjects].isImmutable;
+  }
+
+  /// isDeadObjectIndex - Returns true if the specified index corresponds to
+  /// a dead object.
+  bool isDeadObjectIndex(int ObjectIdx) const {
+    assert(unsigned(ObjectIdx+NumFixedObjects) < Objects.size() &&
+           "Invalid Object Idx!");
+    return Objects[ObjectIdx+NumFixedObjects].Size == ~0ULL;
+  }
+
+  /// CreateStackObject - Create a new statically sized stack object, returning
+  /// a nonnegative identifier to represent it.
+  ///
+  int CreateStackObject(uint64_t Size, unsigned Alignment) {
+    assert(Size != 0 && "Cannot allocate zero size stack objects!");
+    Objects.push_back(StackObject(Size, Alignment));
+    return (int)Objects.size()-NumFixedObjects-1;
+  }
+
+  /// RemoveStackObject - Remove or mark dead a statically sized stack object.
+  ///
+  void RemoveStackObject(int ObjectIdx) {
+    // Mark it dead.
+    Objects[ObjectIdx+NumFixedObjects].Size = ~0ULL;
+  }
+
+  /// CreateVariableSizedObject - Notify the MachineFrameInfo object that a
+  /// variable sized object has been created.  This must be created whenever a
+  /// variable sized object is created, whether or not the index returned is
+  /// actually used.
+  ///
+  int CreateVariableSizedObject() {
+    HasVarSizedObjects = true;
+    Objects.push_back(StackObject(0, 1));
+    return (int)Objects.size()-NumFixedObjects-1;
+  }
+  
+  /// getCalleeSavedInfo - Returns a reference to call saved info vector for the
+  /// current function.
+  const std::vector<CalleeSavedInfo> &getCalleeSavedInfo() const {
+    return CSInfo;
+  }
+
+  /// setCalleeSavedInfo - Used by prolog/epilog inserter to set the function's
+  /// callee saved information.
+  void  setCalleeSavedInfo(const std::vector<CalleeSavedInfo> &CSI) {
+    CSInfo = CSI;
+  }
+
+  /// getMachineModuleInfo - Used by a prologue/epilogue
+  /// emitter (TargetRegisterInfo) to provide frame layout information. 
+  MachineModuleInfo *getMachineModuleInfo() const { return MMI; }
+
+  /// setMachineModuleInfo - Used by a meta info consumer (DwarfWriter) to
+  /// indicate that frame layout information should be gathered.
+  void setMachineModuleInfo(MachineModuleInfo *mmi) { MMI = mmi; }
+
+  /// print - Used by the MachineFunction printer to print information about
+  /// stack objects.  Implemented in MachineFunction.cpp
+  ///
+  void print(const MachineFunction &MF, std::ostream &OS) const;
+
+  /// dump - Call print(MF, std::cerr) to be called from the debugger.
+  void dump(const MachineFunction &MF) const;
+};
+
+} // End llvm namespace
+
+#endif