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      1 //===----------------------- R600FrameLowering.cpp ------------------------===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //==-----------------------------------------------------------------------===//
      8 
      9 #include "R600FrameLowering.h"
     10 #include "R600Subtarget.h"
     11 
     12 using namespace llvm;
     13 
     14 R600FrameLowering::~R600FrameLowering() = default;
     15 
     16 /// \returns The number of registers allocated for \p FI.
     17 StackOffset
     18 R600FrameLowering::getFrameIndexReference(const MachineFunction &MF, int FI,
     19                                           Register &FrameReg) const {
     20   const MachineFrameInfo &MFI = MF.getFrameInfo();
     21   const R600RegisterInfo *RI
     22     = MF.getSubtarget<R600Subtarget>().getRegisterInfo();
     23 
     24   // Fill in FrameReg output argument.
     25   FrameReg = RI->getFrameRegister(MF);
     26 
     27   // Start the offset at 2 so we don't overwrite work group information.
     28   // FIXME: We should only do this when the shader actually uses this
     29   // information.
     30   unsigned OffsetBytes = 2 * (getStackWidth(MF) * 4);
     31   int UpperBound = FI == -1 ? MFI.getNumObjects() : FI;
     32 
     33   for (int i = MFI.getObjectIndexBegin(); i < UpperBound; ++i) {
     34     OffsetBytes = alignTo(OffsetBytes, MFI.getObjectAlign(i));
     35     OffsetBytes += MFI.getObjectSize(i);
     36     // Each register holds 4 bytes, so we must always align the offset to at
     37     // least 4 bytes, so that 2 frame objects won't share the same register.
     38     OffsetBytes = alignTo(OffsetBytes, Align(4));
     39   }
     40 
     41   if (FI != -1)
     42     OffsetBytes = alignTo(OffsetBytes, MFI.getObjectAlign(FI));
     43 
     44   return StackOffset::getFixed(OffsetBytes / (getStackWidth(MF) * 4));
     45 }
     46