1 files changed, 293 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/CallingConvLower.cpp b/llvm/lib/CodeGen/CallingConvLower.cpp
new file mode 100644
index 000000000000..a397039180a4
--- /dev/null
+++ b/llvm/lib/CodeGen/CallingConvLower.cpp
@@ -0,0 +1,293 @@
+//===-- CallingConvLower.cpp - Calling Conventions ------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the CCState class, used for lowering and implementing
+// calling conventions.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/CodeGen/CallingConvLower.h"
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineRegisterInfo.h"
+#include "llvm/CodeGen/TargetLowering.h"
+#include "llvm/CodeGen/TargetRegisterInfo.h"
+#include "llvm/CodeGen/TargetSubtargetInfo.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/SaveAndRestore.h"
+#include "llvm/Support/raw_ostream.h"
+#include <algorithm>
+
+using namespace llvm;
+
+CCState::CCState(CallingConv::ID CC, bool isVarArg, MachineFunction &mf,
+                 SmallVectorImpl<CCValAssign> &locs, LLVMContext &C)
+    : CallingConv(CC), IsVarArg(isVarArg), MF(mf),
+      TRI(*MF.getSubtarget().getRegisterInfo()), Locs(locs), Context(C) {
+  // No stack is used.
+  StackOffset = 0;
+
+  clearByValRegsInfo();
+  UsedRegs.resize((TRI.getNumRegs()+31)/32);
+}
+
+/// Allocate space on the stack large enough to pass an argument by value.
+/// The size and alignment information of the argument is encoded in
+/// its parameter attribute.
+void CCState::HandleByVal(unsigned ValNo, MVT ValVT, MVT LocVT,
+                          CCValAssign::LocInfo LocInfo, int MinSize,
+                          int MinAlignment, ISD::ArgFlagsTy ArgFlags) {
+  Align MinAlign(MinAlignment);
+  Align Alignment(ArgFlags.getByValAlign());
+  unsigned Size  = ArgFlags.getByValSize();
+  if (MinSize > (int)Size)
+    Size = MinSize;
+  if (MinAlign > Alignment)
+    Alignment = MinAlign;
+  ensureMaxAlignment(Alignment);
+  MF.getSubtarget().getTargetLowering()->HandleByVal(this, Size,
+                                                     Alignment.value());
+  Size = unsigned(alignTo(Size, MinAlign));
+  unsigned Offset = AllocateStack(Size, Alignment.value());
+  addLoc(CCValAssign::getMem(ValNo, ValVT, Offset, LocVT, LocInfo));
+}
+
+/// Mark a register and all of its aliases as allocated.
+void CCState::MarkAllocated(unsigned Reg) {
+  for (MCRegAliasIterator AI(Reg, &TRI, true); AI.isValid(); ++AI)
+    UsedRegs[*AI/32] |= 1 << (*AI&31);
+}
+
+bool CCState::IsShadowAllocatedReg(unsigned Reg) const {
+  if (!isAllocated(Reg))
+    return false;
+
+  for (auto const &ValAssign : Locs) {
+    if (ValAssign.isRegLoc()) {
+      for (MCRegAliasIterator AI(ValAssign.getLocReg(), &TRI, true);
+           AI.isValid(); ++AI) {
+        if (*AI == Reg)
+          return false;
+      }
+    }
+  }
+  return true;
+}
+
+/// Analyze an array of argument values,
+/// incorporating info about the formals into this state.
+void
+CCState::AnalyzeFormalArguments(const SmallVectorImpl<ISD::InputArg> &Ins,
+                                CCAssignFn Fn) {
+  unsigned NumArgs = Ins.size();
+
+  for (unsigned i = 0; i != NumArgs; ++i) {
+    MVT ArgVT = Ins[i].VT;
+    ISD::ArgFlagsTy ArgFlags = Ins[i].Flags;
+    if (Fn(i, ArgVT, ArgVT, CCValAssign::Full, ArgFlags, *this))
+      report_fatal_error("unable to allocate function argument #" + Twine(i));
+  }
+}
+
+/// Analyze the return values of a function, returning true if the return can
+/// be performed without sret-demotion and false otherwise.
+bool CCState::CheckReturn(const SmallVectorImpl<ISD::OutputArg> &Outs,
+                          CCAssignFn Fn) {
+  // Determine which register each value should be copied into.
+  for (unsigned i = 0, e = Outs.size(); i != e; ++i) {
+    MVT VT = Outs[i].VT;
+    ISD::ArgFlagsTy ArgFlags = Outs[i].Flags;
+    if (Fn(i, VT, VT, CCValAssign::Full, ArgFlags, *this))
+      return false;
+  }
+  return true;
+}
+
+/// Analyze the returned values of a return,
+/// incorporating info about the result values into this state.
+void CCState::AnalyzeReturn(const SmallVectorImpl<ISD::OutputArg> &Outs,
+                            CCAssignFn Fn) {
+  // Determine which register each value should be copied into.
+  for (unsigned i = 0, e = Outs.size(); i != e; ++i) {
+    MVT VT = Outs[i].VT;
+    ISD::ArgFlagsTy ArgFlags = Outs[i].Flags;
+    if (Fn(i, VT, VT, CCValAssign::Full, ArgFlags, *this))
+      report_fatal_error("unable to allocate function return #" + Twine(i));
+  }
+}
+
+/// Analyze the outgoing arguments to a call,
+/// incorporating info about the passed values into this state.
+void CCState::AnalyzeCallOperands(const SmallVectorImpl<ISD::OutputArg> &Outs,
+                                  CCAssignFn Fn) {
+  unsigned NumOps = Outs.size();
+  for (unsigned i = 0; i != NumOps; ++i) {
+    MVT ArgVT = Outs[i].VT;
+    ISD::ArgFlagsTy ArgFlags = Outs[i].Flags;
+    if (Fn(i, ArgVT, ArgVT, CCValAssign::Full, ArgFlags, *this)) {
+#ifndef NDEBUG
+      dbgs() << "Call operand #" << i << " has unhandled type "
+             << EVT(ArgVT).getEVTString() << '\n';
+#endif
+      llvm_unreachable(nullptr);
+    }
+  }
+}
+
+/// Same as above except it takes vectors of types and argument flags.
+void CCState::AnalyzeCallOperands(SmallVectorImpl<MVT> &ArgVTs,
+                                  SmallVectorImpl<ISD::ArgFlagsTy> &Flags,
+                                  CCAssignFn Fn) {
+  unsigned NumOps = ArgVTs.size();
+  for (unsigned i = 0; i != NumOps; ++i) {
+    MVT ArgVT = ArgVTs[i];
+    ISD::ArgFlagsTy ArgFlags = Flags[i];
+    if (Fn(i, ArgVT, ArgVT, CCValAssign::Full, ArgFlags, *this)) {
+#ifndef NDEBUG
+      dbgs() << "Call operand #" << i << " has unhandled type "
+             << EVT(ArgVT).getEVTString() << '\n';
+#endif
+      llvm_unreachable(nullptr);
+    }
+  }
+}
+
+/// Analyze the return values of a call, incorporating info about the passed
+/// values into this state.
+void CCState::AnalyzeCallResult(const SmallVectorImpl<ISD::InputArg> &Ins,
+                                CCAssignFn Fn) {
+  for (unsigned i = 0, e = Ins.size(); i != e; ++i) {
+    MVT VT = Ins[i].VT;
+    ISD::ArgFlagsTy Flags = Ins[i].Flags;
+    if (Fn(i, VT, VT, CCValAssign::Full, Flags, *this)) {
+#ifndef NDEBUG
+      dbgs() << "Call result #" << i << " has unhandled type "
+             << EVT(VT).getEVTString() << '\n';
+#endif
+      llvm_unreachable(nullptr);
+    }
+  }
+}
+
+/// Same as above except it's specialized for calls that produce a single value.
+void CCState::AnalyzeCallResult(MVT VT, CCAssignFn Fn) {
+  if (Fn(0, VT, VT, CCValAssign::Full, ISD::ArgFlagsTy(), *this)) {
+#ifndef NDEBUG
+    dbgs() << "Call result has unhandled type "
+           << EVT(VT).getEVTString() << '\n';
+#endif
+    llvm_unreachable(nullptr);
+  }
+}
+
+static bool isValueTypeInRegForCC(CallingConv::ID CC, MVT VT) {
+  if (VT.isVector())
+    return true; // Assume -msse-regparm might be in effect.
+  if (!VT.isInteger())
+    return false;
+  if (CC == CallingConv::X86_VectorCall || CC == CallingConv::X86_FastCall)
+    return true;
+  return false;
+}
+
+void CCState::getRemainingRegParmsForType(SmallVectorImpl<MCPhysReg> &Regs,
+                                          MVT VT, CCAssignFn Fn) {
+  unsigned SavedStackOffset = StackOffset;
+  Align SavedMaxStackArgAlign = MaxStackArgAlign;
+  unsigned NumLocs = Locs.size();
+
+  // Set the 'inreg' flag if it is used for this calling convention.
+  ISD::ArgFlagsTy Flags;
+  if (isValueTypeInRegForCC(CallingConv, VT))
+    Flags.setInReg();
+
+  // Allocate something of this value type repeatedly until we get assigned a
+  // location in memory.
+  bool HaveRegParm = true;
+  while (HaveRegParm) {
+    if (Fn(0, VT, VT, CCValAssign::Full, Flags, *this)) {
+#ifndef NDEBUG
+      dbgs() << "Call has unhandled type " << EVT(VT).getEVTString()
+             << " while computing remaining regparms\n";
+#endif
+      llvm_unreachable(nullptr);
+    }
+    HaveRegParm = Locs.back().isRegLoc();
+  }
+
+  // Copy all the registers from the value locations we added.
+  assert(NumLocs < Locs.size() && "CC assignment failed to add location");
+  for (unsigned I = NumLocs, E = Locs.size(); I != E; ++I)
+    if (Locs[I].isRegLoc())
+      Regs.push_back(MCPhysReg(Locs[I].getLocReg()));
+
+  // Clear the assigned values and stack memory. We leave the registers marked
+  // as allocated so that future queries don't return the same registers, i.e.
+  // when i64 and f64 are both passed in GPRs.
+  StackOffset = SavedStackOffset;
+  MaxStackArgAlign = SavedMaxStackArgAlign;
+  Locs.resize(NumLocs);
+}
+
+void CCState::analyzeMustTailForwardedRegisters(
+    SmallVectorImpl<ForwardedRegister> &Forwards, ArrayRef<MVT> RegParmTypes,
+    CCAssignFn Fn) {
+  // Oftentimes calling conventions will not user register parameters for
+  // variadic functions, so we need to assume we're not variadic so that we get
+  // all the registers that might be used in a non-variadic call.
+  SaveAndRestore<bool> SavedVarArg(IsVarArg, false);
+  SaveAndRestore<bool> SavedMustTail(AnalyzingMustTailForwardedRegs, true);
+
+  for (MVT RegVT : RegParmTypes) {
+    SmallVector<MCPhysReg, 8> RemainingRegs;
+    getRemainingRegParmsForType(RemainingRegs, RegVT, Fn);
+    const TargetLowering *TL = MF.getSubtarget().getTargetLowering();
+    const TargetRegisterClass *RC = TL->getRegClassFor(RegVT);
+    for (MCPhysReg PReg : RemainingRegs) {
+      unsigned VReg = MF.addLiveIn(PReg, RC);
+      Forwards.push_back(ForwardedRegister(VReg, PReg, RegVT));
+    }
+  }
+}
+
+bool CCState::resultsCompatible(CallingConv::ID CalleeCC,
+                                CallingConv::ID CallerCC, MachineFunction &MF,
+                                LLVMContext &C,
+                                const SmallVectorImpl<ISD::InputArg> &Ins,
+                                CCAssignFn CalleeFn, CCAssignFn CallerFn) {
+  if (CalleeCC == CallerCC)
+    return true;
+  SmallVector<CCValAssign, 4> RVLocs1;
+  CCState CCInfo1(CalleeCC, false, MF, RVLocs1, C);
+  CCInfo1.AnalyzeCallResult(Ins, CalleeFn);
+
+  SmallVector<CCValAssign, 4> RVLocs2;
+  CCState CCInfo2(CallerCC, false, MF, RVLocs2, C);
+  CCInfo2.AnalyzeCallResult(Ins, CallerFn);
+
+  if (RVLocs1.size() != RVLocs2.size())
+    return false;
+  for (unsigned I = 0, E = RVLocs1.size(); I != E; ++I) {
+    const CCValAssign &Loc1 = RVLocs1[I];
+    const CCValAssign &Loc2 = RVLocs2[I];
+    if (Loc1.getLocInfo() != Loc2.getLocInfo())
+      return false;
+    bool RegLoc1 = Loc1.isRegLoc();
+    if (RegLoc1 != Loc2.isRegLoc())
+      return false;
+    if (RegLoc1) {
+      if (Loc1.getLocReg() != Loc2.getLocReg())
+        return false;
+    } else {
+      if (Loc1.getLocMemOffset() != Loc2.getLocMemOffset())
+        return false;
+    }
+  }
+  return true;
+}