Line data    Source code

       1             : //===----------------------- AMDGPUFrameLowering.cpp ----------------------===//
       2             : //
       3             : //                     The LLVM Compiler Infrastructure
       4             : //
       5             : // This file is distributed under the University of Illinois Open Source
       6             : // License. See LICENSE.TXT for details.
       7             : //
       8             : //==-----------------------------------------------------------------------===//
       9             : //
      10             : // Interface to describe a layout of a stack frame on a AMDGPU target machine.
      11             : //
      12             : //===----------------------------------------------------------------------===//
      13             : 
      14             : #include "AMDGPUFrameLowering.h"
      15             : 
      16             : using namespace llvm;
      17        2783 : AMDGPUFrameLowering::AMDGPUFrameLowering(StackDirection D, unsigned StackAl,
      18             :     int LAO, unsigned TransAl)
      19        2783 :   : TargetFrameLowering(D, StackAl, LAO, TransAl) { }
      20             : 
      21             : AMDGPUFrameLowering::~AMDGPUFrameLowering() = default;
      22             : 
      23       11032 : unsigned AMDGPUFrameLowering::getStackWidth(const MachineFunction &MF) const {
      24             :   // XXX: Hardcoding to 1 for now.
      25             :   //
      26             :   // I think the StackWidth should stored as metadata associated with the
      27             :   // MachineFunction.  This metadata can either be added by a frontend, or
      28             :   // calculated by a R600 specific LLVM IR pass.
      29             :   //
      30             :   // The StackWidth determines how stack objects are laid out in memory.
      31             :   // For a vector stack variable, like: int4 stack[2], the data will be stored
      32             :   // in the following ways depending on the StackWidth.
      33             :   //
      34             :   // StackWidth = 1:
      35             :   //
      36             :   // T0.X = stack[0].x
      37             :   // T1.X = stack[0].y
      38             :   // T2.X = stack[0].z
      39             :   // T3.X = stack[0].w
      40             :   // T4.X = stack[1].x
      41             :   // T5.X = stack[1].y
      42             :   // T6.X = stack[1].z
      43             :   // T7.X = stack[1].w
      44             :   //
      45             :   // StackWidth = 2:
      46             :   //
      47             :   // T0.X = stack[0].x
      48             :   // T0.Y = stack[0].y
      49             :   // T1.X = stack[0].z
      50             :   // T1.Y = stack[0].w
      51             :   // T2.X = stack[1].x
      52             :   // T2.Y = stack[1].y
      53             :   // T3.X = stack[1].z
      54             :   // T3.Y = stack[1].w
      55             :   //
      56             :   // StackWidth = 4:
      57             :   // T0.X = stack[0].x
      58             :   // T0.Y = stack[0].y
      59             :   // T0.Z = stack[0].z
      60             :   // T0.W = stack[0].w
      61             :   // T1.X = stack[1].x
      62             :   // T1.Y = stack[1].y
      63             :   // T1.Z = stack[1].z
      64             :   // T1.W = stack[1].w
      65       11032 :   return 1;
      66             : }