llvm-project/llvm/lib/Target/PowerPC/PPCCallingConv.td

//===- PPCCallingConv.td - Calling Conventions for PowerPC -*- tablegen -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This describes the calling conventions for the PowerPC 32- and 64-bit
// architectures.
//
//===----------------------------------------------------------------------===//

//===----------------------------------------------------------------------===//
// Return Value Calling Convention
//===----------------------------------------------------------------------===//

// Return-value convention for PowerPC
def RetCC_PPC : CallingConv<[
  CCIfType<[i32], CCAssignToReg<[R3, R4, R5, R6, R7, R8, R9, R10]>>,
  CCIfType<[i64], CCAssignToReg<[X3, X4, X5, X6]>>,
  
  CCIfType<[f32], CCAssignToReg<[F1]>>,
  CCIfType<[f64], CCAssignToReg<[F1, F2]>>,
  
  // Vector types are always returned in V2.
  CCIfType<[v16i8, v8i16, v4i32, v4f32], CCAssignToReg<[V2]>>
]>;


//===----------------------------------------------------------------------===//
// PowerPC Argument Calling Conventions
//===----------------------------------------------------------------------===//
/*
def CC_PPC : CallingConv<[
  // The first 8 integer arguments are passed in integer registers.
  CCIfType<[i32], CCAssignToReg<[R3, R4, R5, R6, R7, R8, R9, R10]>>,
  CCIfType<[i64], CCAssignToReg<[X3, X4, X5, X6, X7, X8, X9, X10]>>,
  
  // Common sub-targets passes FP values in F1 - F13
  CCIfType<[f32, f64], 
           CCAssignToReg<[F1, F2, F3, F4, F5, F6, F7, F8,F9,F10,F11,F12,F13]>>,
           
  // The first 12 Vector arguments are passed in altivec registers.
  CCIfType<[v16i8, v8i16, v4i32, v4f32],
              CCAssignToReg<[V2, V3, V4, V5, V6, V7, V8, V9, V10,V11,V12,V13]>>

/*
  // Integer/FP values get stored in stack slots that are 8 bytes in size and
  // 8-byte aligned if there are no more registers to hold them.
  CCIfType<[i32, i64, f32, f64], CCAssignToStack<8, 8>>,
  
  // Vectors get 16-byte stack slots that are 16-byte aligned.
  CCIfType<[v16i8, v8i16, v4i32, v2i64, v4f32, v2f64],
              CCAssignToStack<16, 16>>*/
]>;

*/

//===----------------------------------------------------------------------===//
// PowerPC System V Release 4 ABI
//===----------------------------------------------------------------------===//

def CC_PPC_SVR4_Common : CallingConv<[
  // The ABI requires i64 to be passed in two adjacent registers with the first
  // register having an odd register number.
  CCIfType<[i32], CCIfSplit<CCCustom<"CC_PPC_SVR4_Custom_AlignArgRegs">>>,

  // The first 8 integer arguments are passed in integer registers.
  CCIfType<[i32], CCAssignToReg<[R3, R4, R5, R6, R7, R8, R9, R10]>>,

  // Make sure the i64 words from a long double are either both passed in
  // registers or both passed on the stack.
  CCIfType<[f64], CCIfSplit<CCCustom<"CC_PPC_SVR4_Custom_AlignFPArgRegs">>>,
  
  // FP values are passed in F1 - F8.
  CCIfType<[f32, f64], CCAssignToReg<[F1, F2, F3, F4, F5, F6, F7, F8]>>,

  // Split arguments have an alignment of 8 bytes on the stack.
  CCIfType<[i32], CCIfSplit<CCAssignToStack<4, 8>>>,
  
  CCIfType<[i32], CCAssignToStack<4, 4>>,
  
  // Floats are stored in double precision format, thus they have the same
  // alignment and size as doubles.
  CCIfType<[f32,f64], CCAssignToStack<8, 8>>,  

  // Vectors get 16-byte stack slots that are 16-byte aligned.
  CCIfType<[v16i8, v8i16, v4i32, v4f32], CCAssignToStack<16, 16>>
]>;

// This calling convention puts vector arguments always on the stack. It is used
// to assign vector arguments which belong to the variable portion of the
// parameter list of a variable argument function.
def CC_PPC_SVR4_VarArg : CallingConv<[
  CCDelegateTo<CC_PPC_SVR4_Common>
]>;

// In contrast to CC_PPC_SVR4_VarArg, this calling convention first tries to put
// vector arguments in vector registers before putting them on the stack.
def CC_PPC_SVR4 : CallingConv<[
  // The first 12 Vector arguments are passed in AltiVec registers.
  CCIfType<[v16i8, v8i16, v4i32, v4f32],
           CCAssignToReg<[V2, V3, V4, V5, V6, V7, V8, V9, V10, V11, V12, V13]>>,
           
  CCDelegateTo<CC_PPC_SVR4_Common>
]>;  

// Helper "calling convention" to handle aggregate by value arguments.
// Aggregate by value arguments are always placed in the local variable space
// of the caller. This calling convention is only used to assign those stack
// offsets in the callers stack frame.
//
// Still, the address of the aggregate copy in the callers stack frame is passed
// in a GPR (or in the parameter list area if all GPRs are allocated) from the
// caller to the callee. The location for the address argument is assigned by
// the CC_PPC_SVR4 calling convention.
//
// The only purpose of CC_PPC_SVR4_Custom_Dummy is to skip arguments which are
// not passed by value.
 
def CC_PPC_SVR4_ByVal : CallingConv<[
  CCIfByVal<CCPassByVal<4, 4>>,
  
  CCCustom<"CC_PPC_SVR4_Custom_Dummy">
]>;

def CSR_Darwin32 : CalleeSavedRegs<(add R13, R14, R15, R16, R17, R18, R19, R20,
                                        R21, R22, R23, R24, R25, R26, R27, R28,
                                        R29, R30, R31, F14, F15, F16, F17, F18,
                                        F19, F20, F21, F22, F23, F24, F25, F26,
                                        F27, F28, F29, F30, F31, CR2, CR3, CR4,
                                        V20, V21, V22, V23, V24, V25, V26, V27,
                                        V28, V29, V30, V31)>;

def CSR_SVR432   : CalleeSavedRegs<(add R14, R15, R16, R17, R18, R19, R20, VRSAVE,
                                        R21, R22, R23, R24, R25, R26, R27, R28,
                                        R29, R30, R31, F14, F15, F16, F17, F18,
                                        F19, F20, F21, F22, F23, F24, F25, F26,
                                        F27, F28, F29, F30, F31, CR2, CR3, CR4,
                                        V20, V21, V22, V23, V24, V25, V26, V27,
                                        V28, V29, V30, V31)>;

def CSR_Darwin64 : CalleeSavedRegs<(add X13, X14, X15, X16, X17, X18, X19, X20,
                                        X21, X22, X23, X24, X25, X26, X27, X28,
                                        X29, X30, X31, F14, F15, F16, F17, F18,
                                        F19, F20, F21, F22, F23, F24, F25, F26,
                                        F27, F28, F29, F30, F31, CR2, CR3, CR4,
                                        V20, V21, V22, V23, V24, V25, V26, V27,
                                        V28, V29, V30, V31)>;

def CSR_SVR464   : CalleeSavedRegs<(add X14, X15, X16, X17, X18, X19, X20, VRSAVE,
                                        X21, X22, X23, X24, X25, X26, X27, X28,
                                        X29, X30, X31, F14, F15, F16, F17, F18,
                                        F19, F20, F21, F22, F23, F24, F25, F26,
                                        F27, F28, F29, F30, F31, CR2, CR3, CR4,
                                        V20, V21, V22, V23, V24, V25, V26, V27,
                                        V28, V29, V30, V31)>;