llvm/lib/Target/Target.td

//===- Target.td - Target Independent TableGen interface --------*- C++ -*-===//
//
// This file defines the target-independent interfaces which should be
// implemented by each target which is using a TableGen based code generator.
//
//===----------------------------------------------------------------------===//


//===----------------------------------------------------------------------===//
//
// Value types - These values correspond to the register types defined in the
// ValueTypes.h file.
//
class ValueType<int size> { string Namespace = "MVT"; int Size = size; }

def i1   : ValueType<1>;      // One bit boolean value
def i8   : ValueType<8>;      // 8-bit integer value
def i16  : ValueType<16>;     // 16-bit integer value
def i32  : ValueType<32>;     // 32-bit integer value
def i64  : ValueType<64>;     // 64-bit integer value
def i128 : ValueType<128>;    // 128-bit integer value
def f32  : ValueType<32>;     // 32-bit floating point value
def f64  : ValueType<64>;     // 64-bit floating point value
def f80  : ValueType<80>;     // 80-bit floating point value
def f128 : ValueType<128>;    // 128-bit floating point value


//===----------------------------------------------------------------------===//
// Register file description - These classes are used to fill in the target
// description classes in llvm/Target/MRegisterInfo.h


// Register - You should define one instance of this class for each register in
// the target machine.
//
class Register {
  string Namespace = "";
}

// RegisterAliases - You should define instances of this class to indicate which
// registers in the register file are aliased together.  This allows the code
// generator to be careful not to put two values with overlapping live ranges
// into registers which alias.
//
class RegisterAliases<Register reg, list<Register> aliases> {
  Register Reg = reg;
  list<Register> Aliases = aliases;
}

// RegisterClass - Now that all of the registers are defined, and aliases
// between registers are defined, specify which registers belong to which
// register classes.  This also defines the default allocation order of
// registers by register allocators.
//
class RegisterClass<ValueType regType, int alignment, list<Register> regList> {
  // RegType - Specify the ValueType of the registers in this register class.
  // Note that all registers in a register class must have the same ValueType.
  //
  ValueType RegType = regType;

  // Alignment - Specify the alignment required of the registers when they are
  // stored or loaded to memory.
  //
  int Size = RegType.Size;
  int Alignment = alignment;

  // MemberList - Specify which registers are in this class.  If the
  // allocation_order_* method are not specified, this also defines the order of
  // allocation used by the register allocator.
  //
  list<Register> MemberList = regList;

  // Methods - This member can be used to insert arbitrary code into a generated
  // register class.   The normal usage of this is to overload virtual methods.
  code Methods = [{}];
}

// RegisterInfo - This class should only be instantiated once to provide
// parameters which are global to the the target machine, such as callee safed
// registers.
//
class RegisterInfo {
  // ClassName - Specify the name of the class that should be generated by the
  // register info emitter.  This class may be further subclasses by custom
  // target code to implement virtual methods as necessary.  Targets must
  // specify a value for this.
  //
  string ClassName;

  // CalleeSavedRegisters - As you might guess, this is a list of the callee
  // saved registers for a target.
  list<Register> CalleeSavedRegisters = [];
  
  // PointerType - Specify the value type to be used to represent pointers in
  // this target.  Typically this is an i32 or i64 type.
  ValueType PointerType;
}


//===----------------------------------------------------------------------===//
// Instruction set description - 
//

class Instruction {
  string Name;          // The opcode string for this instruction
  string Namespace = "";

  list<Register> Uses = [];  // Default to using no non-operand registers
  list<Register> Defs = [];  // Default to modifying no non-operand registers

  // These bits capture information about the high-level semantics of the
  // instruction.
  bit isReturn     = 0;     // Is this instruction a return instruction?
  bit isBranch     = 0;     // Is this instruction a branch instruction?
  bit isCall       = 0;     // Is this instruction a call instruction?
  bit isTwoAddress = 0;     // Is this a two address instruction?
  bit isTerminator = 0;     // Is this part of the terminator for a basic block?
}