1 files changed, 49 insertions, 0 deletions
diff --git a/llvm/lib/Target/AMDGPU/R600FrameLowering.cpp b/llvm/lib/Target/AMDGPU/R600FrameLowering.cpp
new file mode 100644
index 000000000000..d9aa9ebe878d
--- /dev/null
+++ b/llvm/lib/Target/AMDGPU/R600FrameLowering.cpp
@@ -0,0 +1,49 @@
+//===----------------------- R600FrameLowering.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
+//
+//==-----------------------------------------------------------------------===//
+
+#include "R600FrameLowering.h"
+#include "AMDGPUSubtarget.h"
+#include "R600RegisterInfo.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/Support/MathExtras.h"
+
+using namespace llvm;
+
+R600FrameLowering::~R600FrameLowering() = default;
+
+/// \returns The number of registers allocated for \p FI.
+int R600FrameLowering::getFrameIndexReference(const MachineFunction &MF,
+                                              int FI,
+                                              unsigned &FrameReg) const {
+  const MachineFrameInfo &MFI = MF.getFrameInfo();
+  const R600RegisterInfo *RI
+    = MF.getSubtarget<R600Subtarget>().getRegisterInfo();
+
+  // Fill in FrameReg output argument.
+  FrameReg = RI->getFrameRegister(MF);
+
+  // Start the offset at 2 so we don't overwrite work group information.
+  // FIXME: We should only do this when the shader actually uses this
+  // information.
+  unsigned OffsetBytes = 2 * (getStackWidth(MF) * 4);
+  int UpperBound = FI == -1 ? MFI.getNumObjects() : FI;
+
+  for (int i = MFI.getObjectIndexBegin(); i < UpperBound; ++i) {
+    OffsetBytes = alignTo(OffsetBytes, MFI.getObjectAlignment(i));
+    OffsetBytes += MFI.getObjectSize(i);
+    // Each register holds 4 bytes, so we must always align the offset to at
+    // least 4 bytes, so that 2 frame objects won't share the same register.
+    OffsetBytes = alignTo(OffsetBytes, 4);
+  }
+
+  if (FI != -1)
+    OffsetBytes = alignTo(OffsetBytes, MFI.getObjectAlignment(FI));
+
+  return OffsetBytes / (getStackWidth(MF) * 4);
+}