1
0
mirror of https://github.com/RPCS3/llvm-mirror.git synced 2024-11-26 04:32:44 +01:00
llvm-mirror/include/llvm/CodeGen/InstrSelectionSupport.h
Vikram S. Adve c83118d53f 1. Add a bottom-up pass on BURG trees that is used to fix constant operands.
Needs to be bottom up because constant values may be forward-substituted
   to their uses (i.e., into the parent in the BURG tree).
2. Move most of the constant-fixup code into machine-indepedent file
   InstrSelectionSupport.cpp.

llvm-svn: 860
2001-10-17 23:59:09 +00:00

141 lines
5.1 KiB
C++

// $Id$ -*-c++-*-
//***************************************************************************
// File:
// InstrSelectionSupport.h
//
// Purpose:
// Target-independent instruction selection code.
// See SparcInstrSelection.cpp for usage.
//
// History:
// 10/10/01 - Vikram Adve - Created
//**************************************************************************/
#ifndef LLVM_CODEGEN_INSTR_SELECTION_SUPPORT_H
#define LLVM_CODEGEN_INSTR_SELECTION_SUPPORT_H
#include "llvm/Instruction.h"
#include "llvm/CodeGen/MachineInstr.h"
class Method;
class InstrForest;
class MachineInstr;
class InstructionNode;
class TmpInstruction;
class ConstPoolVal;
class TargetMachine;
//************************ Exported Functions ******************************/
//---------------------------------------------------------------------------
// Function GetConstantValueAsSignedInt
//
// Convenience function to get the value of an integer constant, for an
// appropriate integer or non-integer type that can be held in an integer.
// The type of the argument must be the following:
// Signed or unsigned integer
// Boolean
// Pointer
//
// isValidConstant is set to true if a valid constant was found.
//---------------------------------------------------------------------------
int64_t GetConstantValueAsSignedInt (const Value *V,
bool &isValidConstant);
//---------------------------------------------------------------------------
// Function: FoldGetElemChain
//
// Purpose:
// Fold a chain of GetElementPtr instructions into an equivalent
// (Pointer, IndexVector) pair. Returns the pointer Value, and
// stores the resulting IndexVector in argument chainIdxVec.
//---------------------------------------------------------------------------
Value* FoldGetElemChain (const InstructionNode* getElemInstrNode,
vector<ConstPoolVal*>& chainIdxVec);
//------------------------------------------------------------------------
// Function Set2OperandsFromInstr
// Function Set3OperandsFromInstr
//
// Purpose:
//
// For the common case of 2- and 3-operand arithmetic/logical instructions,
// set the m/c instr. operands directly from the VM instruction's operands.
// Check whether the first or second operand is 0 and can use a dedicated
// "0" register.
// Check whether the second operand should use an immediate field or register.
// (First and third operands are never immediates for such instructions.)
//
// Arguments:
// canDiscardResult: Specifies that the result operand can be discarded
// by using the dedicated "0"
//
// op1position, op2position and resultPosition: Specify in which position
// in the machine instruction the 3 operands (arg1, arg2
// and result) should go.
//
// RETURN VALUE: unsigned int flags, where
// flags & 0x01 => operand 1 is constant and needs a register
// flags & 0x02 => operand 2 is constant and needs a register
//------------------------------------------------------------------------
void Set2OperandsFromInstr (MachineInstr* minstr,
InstructionNode* vmInstrNode,
const TargetMachine& targetMachine,
bool canDiscardResult = false,
int op1Position = 0,
int resultPosition = 1);
void Set3OperandsFromInstr (MachineInstr* minstr,
InstructionNode* vmInstrNode,
const TargetMachine& targetMachine,
bool canDiscardResult = false,
int op1Position = 0,
int op2Position = 1,
int resultPosition = 2);
//---------------------------------------------------------------------------
// Function: ChooseRegOrImmed
//
// Purpose:
//
//---------------------------------------------------------------------------
MachineOperand::MachineOperandType
ChooseRegOrImmed (Value* val,
MachineOpCode opCode,
const TargetMachine& targetMachine,
bool canUseImmed,
unsigned int& getMachineRegNum,
int64_t& getImmedValue);
//---------------------------------------------------------------------------
// Function: FixConstantOperandsForInstr
//
// Purpose:
// Special handling for constant operands of a machine instruction
// -- if the constant is 0, use the hardwired 0 register, if any;
// -- if the constant fits in the IMMEDIATE field, use that field;
// -- else create instructions to put the constant into a register, either
// directly or by loading explicitly from the constant pool.
//
// In the first 2 cases, the operand of `minstr' is modified in place.
// Returns a vector of machine instructions generated for operands that
// fall under case 3; these must be inserted before `minstr'.
//---------------------------------------------------------------------------
vector<MachineInstr*> FixConstantOperandsForInstr (Instruction* vmInstr,
MachineInstr* minstr,
TargetMachine& target);
//**************************************************************************/
#endif