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| //===----------------------- AMDGPUFrameLowering.cpp ----------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//==-----------------------------------------------------------------------===//
//
// Interface to describe a layout of a stack frame on a AMDGPU target machine.
//
//===----------------------------------------------------------------------===//
#include "AMDGPUFrameLowering.h"
using namespace llvm;
AMDGPUFrameLowering::AMDGPUFrameLowering(StackDirection D, Align StackAl,
int LAO, Align TransAl)
: TargetFrameLowering(D, StackAl, LAO, TransAl) {}
AMDGPUFrameLowering::~AMDGPUFrameLowering() = default;
unsigned AMDGPUFrameLowering::getStackWidth(const MachineFunction &MF) const {
// XXX: Hardcoding to 1 for now.
//
// I think the StackWidth should stored as metadata associated with the
// MachineFunction. This metadata can either be added by a frontend, or
// calculated by a R600 specific LLVM IR pass.
//
// The StackWidth determines how stack objects are laid out in memory.
// For a vector stack variable, like: int4 stack[2], the data will be stored
// in the following ways depending on the StackWidth.
//
// StackWidth = 1:
//
// T0.X = stack[0].x
// T1.X = stack[0].y
// T2.X = stack[0].z
// T3.X = stack[0].w
// T4.X = stack[1].x
// T5.X = stack[1].y
// T6.X = stack[1].z
// T7.X = stack[1].w
//
// StackWidth = 2:
//
// T0.X = stack[0].x
// T0.Y = stack[0].y
// T1.X = stack[0].z
// T1.Y = stack[0].w
// T2.X = stack[1].x
// T2.Y = stack[1].y
// T3.X = stack[1].z
// T3.Y = stack[1].w
//
// StackWidth = 4:
// T0.X = stack[0].x
// T0.Y = stack[0].y
// T0.Z = stack[0].z
// T0.W = stack[0].w
// T1.X = stack[1].x
// T1.Y = stack[1].y
// T1.Z = stack[1].z
// T1.W = stack[1].w
return 1;
}
|