1 files changed, 124 insertions, 0 deletions
diff --git a/lib/Target/Blackfin/BlackfinFrameLowering.cpp b/lib/Target/Blackfin/BlackfinFrameLowering.cpp
new file mode 100644
index 0000000000..594325f95c
--- /dev/null
+++ b/lib/Target/Blackfin/BlackfinFrameLowering.cpp
@@ -0,0 +1,124 @@
+//====- BlackfinFrameLowering.cpp - Blackfin Frame Information --*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains the Blackfin implementation of TargetFrameLowering class.
+//
+//===----------------------------------------------------------------------===//
+
+#include "BlackfinFrameLowering.h"
+#include "BlackfinInstrInfo.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineInstrBuilder.h"
+#include "llvm/CodeGen/RegisterScavenging.h"
+#include "llvm/Target/TargetOptions.h"
+
+using namespace llvm;
+
+
+// hasFP - Return true if the specified function should have a dedicated frame
+// pointer register.  This is true if the function has variable sized allocas or
+// if frame pointer elimination is disabled.
+bool BlackfinFrameLowering::hasFP(const MachineFunction &MF) const {
+  const MachineFrameInfo *MFI = MF.getFrameInfo();
+  return DisableFramePointerElim(MF) ||
+    MFI->adjustsStack() || MFI->hasVarSizedObjects();
+}
+
+// Emit a prologue that sets up a stack frame.
+// On function entry, R0-R2 and P0 may hold arguments.
+// R3, P1, and P2 may be used as scratch registers
+void BlackfinFrameLowering::emitPrologue(MachineFunction &MF) const {
+  MachineBasicBlock &MBB = MF.front();   // Prolog goes in entry BB
+  MachineBasicBlock::iterator MBBI = MBB.begin();
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  const BlackfinRegisterInfo *RegInfo =
+    static_cast<const BlackfinRegisterInfo*>(MF.getTarget().getRegisterInfo());
+  const BlackfinInstrInfo &TII =
+    *static_cast<const BlackfinInstrInfo*>(MF.getTarget().getInstrInfo());
+
+  DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();
+
+  int FrameSize = MFI->getStackSize();
+  if (FrameSize%4) {
+    FrameSize = (FrameSize+3) & ~3;
+    MFI->setStackSize(FrameSize);
+  }
+
+  if (!hasFP(MF)) {
+    assert(!MFI->adjustsStack() &&
+           "FP elimination on a non-leaf function is not supported");
+    RegInfo->adjustRegister(MBB, MBBI, dl, BF::SP, BF::P1, -FrameSize);
+    return;
+  }
+
+  // emit a LINK instruction
+  if (FrameSize <= 0x3ffff) {
+    BuildMI(MBB, MBBI, dl, TII.get(BF::LINK)).addImm(FrameSize);
+    return;
+  }
+
+  // Frame is too big, do a manual LINK:
+  // [--SP] = RETS;
+  // [--SP] = FP;
+  // FP = SP;
+  // P1 = -FrameSize;
+  // SP = SP + P1;
+  BuildMI(MBB, MBBI, dl, TII.get(BF::PUSH))
+    .addReg(BF::RETS, RegState::Kill);
+  BuildMI(MBB, MBBI, dl, TII.get(BF::PUSH))
+    .addReg(BF::FP, RegState::Kill);
+  BuildMI(MBB, MBBI, dl, TII.get(BF::MOVE), BF::FP)
+    .addReg(BF::SP);
+  RegInfo->loadConstant(MBB, MBBI, dl, BF::P1, -FrameSize);
+  BuildMI(MBB, MBBI, dl, TII.get(BF::ADDpp), BF::SP)
+    .addReg(BF::SP, RegState::Kill)
+    .addReg(BF::P1, RegState::Kill);
+
+}
+
+void BlackfinFrameLowering::emitEpilogue(MachineFunction &MF,
+                                     MachineBasicBlock &MBB) const {
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  const BlackfinRegisterInfo *RegInfo =
+    static_cast<const BlackfinRegisterInfo*>(MF.getTarget().getRegisterInfo());
+  const BlackfinInstrInfo &TII =
+    *static_cast<const BlackfinInstrInfo*>(MF.getTarget().getInstrInfo());
+  MachineBasicBlock::iterator MBBI = prior(MBB.end());
+  DebugLoc dl = MBBI->getDebugLoc();
+
+  int FrameSize = MFI->getStackSize();
+  assert(FrameSize%4 == 0 && "Misaligned frame size");
+
+  if (!hasFP(MF)) {
+    assert(!MFI->adjustsStack() &&
+           "FP elimination on a non-leaf function is not supported");
+    RegInfo->adjustRegister(MBB, MBBI, dl, BF::SP, BF::P1, FrameSize);
+    return;
+  }
+
+  // emit an UNLINK instruction
+  BuildMI(MBB, MBBI, dl, TII.get(BF::UNLINK));
+}
+
+void BlackfinFrameLowering::
+processFunctionBeforeCalleeSavedScan(MachineFunction &MF,
+                                     RegScavenger *RS) const {
+  MachineFrameInfo *MFI = MF.getFrameInfo();
+  const BlackfinRegisterInfo *RegInfo =
+    static_cast<const BlackfinRegisterInfo*>(MF.getTarget().getRegisterInfo());
+  const TargetRegisterClass *RC = BF::DPRegisterClass;
+
+  if (RegInfo->requiresRegisterScavenging(MF)) {
+    // Reserve a slot close to SP or frame pointer.
+    RS->setScavengingFrameIndex(MFI->CreateStackObject(RC->getSize(),
+                                                       RC->getAlignment(),
+                                                       false));
+  }
+}