llvm-6502/lib/Target/SystemZ/SystemZCallingConv.td

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//=- SystemZCallingConv.td - Calling conventions for SystemZ -*- 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 SystemZ ABI.
//===----------------------------------------------------------------------===//
class CCIfExtend<CCAction A>
: CCIf<"ArgFlags.isSExt() || ArgFlags.isZExt()", A>;
//===----------------------------------------------------------------------===//
// SVR4 return value calling convention
//===----------------------------------------------------------------------===//
def RetCC_SystemZ : CallingConv<[
// Promote i32 to i64 if it has an explicit extension type.
CCIfType<[i32], CCIfExtend<CCPromoteToType<i64>>>,
// ABI-compliant code returns 64-bit integers in R2. Make the other
// call-clobbered argument registers available for code that doesn't
// care about the ABI. (R6 is an argument register too, but is
// call-saved and therefore not suitable for return values.)
CCIfType<[i32], CCAssignToReg<[R2W, R3W, R4W, R5W]>>,
CCIfType<[i64], CCAssignToReg<[R2D, R3D, R4D, R5D]>>,
// ABI-complaint code returns float and double in F0. Make the
// other floating-point argument registers available for code that
// doesn't care about the ABI. All floating-point argument registers
// are call-clobbered, so we can use all of them here.
CCIfType<[f32], CCAssignToReg<[F0S, F2S, F4S, F6S]>>,
CCIfType<[f64], CCAssignToReg<[F0D, F2D, F4D, F6D]>>
// ABI-compliant code returns long double by reference, but that conversion
// is left to higher-level code. Perhaps we could add an f128 definition
// here for code that doesn't care about the ABI?
]>;
//===----------------------------------------------------------------------===//
// SVR4 argument calling conventions
//===----------------------------------------------------------------------===//
def CC_SystemZ : CallingConv<[
// Promote i32 to i64 if it has an explicit extension type.
// The convention is that true integer arguments that are smaller
// than 64 bits should be marked as extended, but structures that
// are smaller than 64 bits shouldn't.
CCIfType<[i32], CCIfExtend<CCPromoteToType<i64>>>,
// Force long double values to the stack and pass i64 pointers to them.
CCIfType<[f128], CCPassIndirect<i64>>,
// The first 5 integer arguments are passed in R2-R6. Note that R6
// is call-saved.
CCIfType<[i32], CCAssignToReg<[R2W, R3W, R4W, R5W, R6W]>>,
CCIfType<[i64], CCAssignToReg<[R2D, R3D, R4D, R5D, R6D]>>,
// The first 4 float and double arguments are passed in even registers F0-F6.
CCIfType<[f32], CCAssignToReg<[F0S, F2S, F4S, F6S]>>,
CCIfType<[f64], CCAssignToReg<[F0D, F2D, F4D, F6D]>>,
// Other arguments are passed in 8-byte-aligned 8-byte stack slots.
CCIfType<[i32, i64, f32, f64], CCAssignToStack<8, 8>>
]>;