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 "AMDGPUSubtarget.h" 11 #include "R600RegisterInfo.h" 12 #include "llvm/CodeGen/MachineFrameInfo.h" 13 #include "llvm/CodeGen/MachineFunction.h" 14 #include "llvm/Support/MathExtras.h" 15 16 using namespace llvm; 17 18 R600FrameLowering::~R600FrameLowering() = default; 19 20 /// \returns The number of registers allocated for \p FI. 21 int R600FrameLowering::getFrameIndexReference(const MachineFunction &MF, 22 int FI, 23 unsigned &FrameReg) const { 24 const MachineFrameInfo &MFI = MF.getFrameInfo(); 25 const R600RegisterInfo *RI 26 = MF.getSubtarget<R600Subtarget>().getRegisterInfo(); 27 28 // Fill in FrameReg output argument. 29 FrameReg = RI->getFrameRegister(MF); 30 31 // Start the offset at 2 so we don't overwrite work group information. 32 // FIXME: We should only do this when the shader actually uses this 33 // information. 34 unsigned OffsetBytes = 2 * (getStackWidth(MF) * 4); 35 int UpperBound = FI == -1 ? MFI.getNumObjects() : FI; 36 37 for (int i = MFI.getObjectIndexBegin(); i < UpperBound; ++i) { 38 OffsetBytes = alignTo(OffsetBytes, MFI.getObjectAlignment(i)); 39 OffsetBytes += MFI.getObjectSize(i); 40 // Each register holds 4 bytes, so we must always align the offset to at 41 // least 4 bytes, so that 2 frame objects won't share the same register. 42 OffsetBytes = alignTo(OffsetBytes, 4); 43 } 44 45 if (FI != -1) 46 OffsetBytes = alignTo(OffsetBytes, MFI.getObjectAlignment(FI)); 47 48 return OffsetBytes / (getStackWidth(MF) * 4); 49 } 50