//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
-// 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 positive 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.
+// 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
- unsigned Size;
+ // 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.
- int SPOffset;
-
- StackObject(unsigned Sz, unsigned Al, int SP)
- : Size(Sz), Alignment(Al), SPOffset(SP) {}
+ 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...
///
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.
///
- unsigned StackSize;
+ 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. In these cases, MaxAlignment is set to the new alignment
- /// necessary to easily calculate fixed offsets for each stack object.
+ /// 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;
/// 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
/// 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:
- MachineFrameInfo() {
- NumFixedObjects = StackSize = MaxAlignment = 0;
+ 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
///
bool hasVarSizedObjects() const { return HasVarSizedObjects; }
- /// getObjectIndexBegin - Return the minimum frame object index...
+ /// 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...
+ /// getObjectIndexEnd - Return one past the maximum frame object index.
///
- int getObjectIndexEnd() const { return Objects.size()-NumFixedObjects; }
+ int getObjectIndexEnd() const { return (int)Objects.size()-NumFixedObjects; }
- /// getObjectSize - Return the size of the specified object
+ /// getNumFixedObjects() - Return the number of fixed objects.
+ unsigned getNumFixedObjects() const { return NumFixedObjects; }
+
+ /// getNumObjects() - Return the number of objects.
///
- int getObjectSize(int ObjectIdx) const {
- assert(ObjectIdx+NumFixedObjects < Objects.size() && "Invalid Object Idx!");
+ 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;
}
- /// getObjectAlignment - Return the alignment of the specified stack object...
- int getObjectAlignment(int ObjectIdx) const {
- assert(ObjectIdx+NumFixedObjects < Objects.size() && "Invalid Object Idx!");
+ /// 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.
///
- int getObjectOffset(int ObjectIdx) const {
- assert(ObjectIdx+NumFixedObjects < Objects.size() && "Invalid Object Idx!");
+ 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, int SPOffset) {
- assert(ObjectIdx+NumFixedObjects < Objects.size() && "Invalid Object Idx!");
+ 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;
}
/// all of the fixed size frame objects. This is only valid after
/// Prolog/Epilog code insertion has finalized the stack frame layout.
///
- unsigned getStackSize() const { return StackSize; }
+ uint64_t getStackSize() const { return StackSize; }
/// setStackSize - Set the size of the stack...
///
- void setStackSize(unsigned Size) { StackSize = Size; }
+ 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
/// 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. This returns an index with a negative value.
+ /// efficiency. By default, fixed objects are immutable. This returns an
+ /// index with a negative value.
///
- int CreateFixedObject(unsigned Size, int SPOffset) {
- assert(Size != 0 && "Cannot allocate zero size fixed stack objects!");
- Objects.insert(Objects.begin(), StackObject(Size, 1, SPOffset));
- return -++NumFixedObjects;
+ 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 postive identifier to represent it.
+ /// a nonnegative identifier to represent it.
///
- int CreateStackObject(unsigned Size, unsigned Alignment) {
+ int CreateStackObject(uint64_t Size, unsigned Alignment) {
assert(Size != 0 && "Cannot allocate zero size stack objects!");
- Objects.push_back(StackObject(Size, Alignment, -1));
- return Objects.size()-NumFixedObjects-1;
+ Objects.push_back(StackObject(Size, Alignment));
+ return (int)Objects.size()-NumFixedObjects-1;
}
- /// CreateStackObject - Create a stack object for a value of the specified
- /// LLVM type.
+ /// RemoveStackObject - Remove or mark dead a statically sized stack object.
///
- int CreateStackObject(const Type *Ty, const TargetData &TD);
+ 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
///
int CreateVariableSizedObject() {
HasVarSizedObjects = true;
- Objects.push_back(StackObject(0, 1, -1));
- return Objects.size()-NumFixedObjects-1;
+ 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
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