| //===----------------------- 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, unsigned 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; |
| } |