R600 -> AMDGPU rename

[oota-llvm.git] / lib / Target / AMDGPU / AMDGPUFrameLowering.cpp

diff --git a/lib/Target/AMDGPU/AMDGPUFrameLowering.cpp b/lib/Target/AMDGPU/AMDGPUFrameLowering.cpp
new file mode 100644 (file)
index 0000000..8175786
--- /dev/null
+++ b/lib/Target/AMDGPU/AMDGPUFrameLowering.cpp
@@ -0,0 +1,112 @@
+//===----------------------- AMDGPUFrameLowering.cpp ----------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//==-----------------------------------------------------------------------===//
+//
+// Interface to describe a layout of a stack frame on a AMDIL target machine
+//
+//===----------------------------------------------------------------------===//
+#include "AMDGPUFrameLowering.h"
+#include "AMDGPURegisterInfo.h"
+#include "R600MachineFunctionInfo.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/IR/Instructions.h"
+
+using namespace llvm;
+AMDGPUFrameLowering::AMDGPUFrameLowering(StackDirection D, unsigned StackAl,
+    int LAO, unsigned TransAl)
+  : TargetFrameLowering(D, StackAl, LAO, TransAl) { }
+
+AMDGPUFrameLowering::~AMDGPUFrameLowering() { }
+
+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;
+}
+
+/// \returns The number of registers allocated for \p FI.
+int AMDGPUFrameLowering::getFrameIndexOffset(const MachineFunction &MF,
+                                         int FI) const {
+  const MachineFrameInfo *MFI = MF.getFrameInfo();
+  // Start the offset at 2 so we don't overwrite work group information.
+  // XXX: 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 = RoundUpToAlignment(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 = RoundUpToAlignment(OffsetBytes, 4);
+  }
+
+  if (FI != -1)
+    OffsetBytes = RoundUpToAlignment(OffsetBytes, MFI->getObjectAlignment(FI));
+
+  return OffsetBytes / (getStackWidth(MF) * 4);
+}
+
+const TargetFrameLowering::SpillSlot *
+AMDGPUFrameLowering::getCalleeSavedSpillSlots(unsigned &NumEntries) const {
+  NumEntries = 0;
+  return nullptr;
+}
+void AMDGPUFrameLowering::emitPrologue(MachineFunction &MF,
+                                       MachineBasicBlock &MBB) const {}
+void
+AMDGPUFrameLowering::emitEpilogue(MachineFunction &MF,
+                                  MachineBasicBlock &MBB) const {
+}
+
+bool
+AMDGPUFrameLowering::hasFP(const MachineFunction &MF) const {
+  return false;
+}