llvm/lib/Target/SystemZ/SystemZCallingConv.h

   1 //===-- SystemZCallingConv.h - Calling conventions for SystemZ --*- C++ -*-===//
   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 #ifndef LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZCALLINGCONV_H
  10 #define LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZCALLINGCONV_H
  11
  12 #include "SystemZSubtarget.h"
  13 #include "llvm/ADT/SmallVector.h"
  14 #include "llvm/CodeGen/CallingConvLower.h"
  15 #include "llvm/MC/MCRegisterInfo.h"
  16
  17 namespace llvm {
  18 namespace SystemZ {
  19   const unsigned ELFNumArgGPRs = 5;
  20   extern const MCPhysReg ELFArgGPRs[ELFNumArgGPRs];
  21
  22   const unsigned ELFNumArgFPRs = 4;
  23   extern const MCPhysReg ELFArgFPRs[ELFNumArgFPRs];
  24
  25   const unsigned XPLINK64NumArgGPRs = 3;
  26   extern const MCPhysReg XPLINK64ArgGPRs[XPLINK64NumArgGPRs];
  27
  28   const unsigned XPLINK64NumArgFPRs = 4;
  29   extern const MCPhysReg XPLINK64ArgFPRs[XPLINK64NumArgFPRs];
  30 } // end namespace SystemZ
  31
  32 class SystemZCCState : public CCState {
  33 private:
  34   /// Records whether the value was a fixed argument.
  35   /// See ISD::OutputArg::IsFixed.
  36   SmallVector<bool, 4> ArgIsFixed;
  37
  38   /// Records whether the value was widened from a short vector type.
  39   SmallVector<bool, 4> ArgIsShortVector;
  40
  41   // Check whether ArgVT is a short vector type.
  42   bool IsShortVectorType(EVT ArgVT) {
  43     return ArgVT.isVector() && ArgVT.getStoreSize() <= 8;
  44   }
  45
  46 public:
  47   SystemZCCState(CallingConv::ID CC, bool isVarArg, MachineFunction &MF,
  48                  SmallVectorImpl<CCValAssign> &locs, LLVMContext &C)
  49       : CCState(CC, isVarArg, MF, locs, C) {}
  50
  51   void AnalyzeFormalArguments(const SmallVectorImpl<ISD::InputArg> &Ins,
  52                               CCAssignFn Fn) {
  53     // Formal arguments are always fixed.
  54     ArgIsFixed.clear();
  55     for (unsigned i = 0; i < Ins.size(); ++i)
  56       ArgIsFixed.push_back(true);
  57     // Record whether the call operand was a short vector.
  58     ArgIsShortVector.clear();
  59     for (unsigned i = 0; i < Ins.size(); ++i)
  60       ArgIsShortVector.push_back(IsShortVectorType(Ins[i].ArgVT));
  61
  62     CCState::AnalyzeFormalArguments(Ins, Fn);
  63   }
  64
  65   void AnalyzeCallOperands(const SmallVectorImpl<ISD::OutputArg> &Outs,
  66                            CCAssignFn Fn) {
  67     // Record whether the call operand was a fixed argument.
  68     ArgIsFixed.clear();
  69     for (unsigned i = 0; i < Outs.size(); ++i)
  70       ArgIsFixed.push_back(Outs[i].IsFixed);
  71     // Record whether the call operand was a short vector.
  72     ArgIsShortVector.clear();
  73     for (unsigned i = 0; i < Outs.size(); ++i)
  74       ArgIsShortVector.push_back(IsShortVectorType(Outs[i].ArgVT));
  75
  76     CCState::AnalyzeCallOperands(Outs, Fn);
  77   }
  78
  79   // This version of AnalyzeCallOperands in the base class is not usable
  80   // since we must provide a means of accessing ISD::OutputArg::IsFixed.
  81   void AnalyzeCallOperands(const SmallVectorImpl<MVT> &Outs,
  82                            SmallVectorImpl<ISD::ArgFlagsTy> &Flags,
  83                            CCAssignFn Fn) = delete;
  84
  85   bool IsFixed(unsigned ValNo) { return ArgIsFixed[ValNo]; }
  86   bool IsShortVector(unsigned ValNo) { return ArgIsShortVector[ValNo]; }
  87 };
  88
  89 // Handle i128 argument types.  These need to be passed by implicit
  90 // reference.  This could be as simple as the following .td line:
  91 //    CCIfType<[i128], CCPassIndirect<i64>>,
  92 // except that i128 is not a legal type, and therefore gets split by
  93 // common code into a pair of i64 arguments.
  94 inline bool CC_SystemZ_I128Indirect(unsigned &ValNo, MVT &ValVT,
  95                                     MVT &LocVT,
  96                                     CCValAssign::LocInfo &LocInfo,
  97                                     ISD::ArgFlagsTy &ArgFlags,
  98                                     CCState &State) {
  99   SmallVectorImpl<CCValAssign> &PendingMembers = State.getPendingLocs();
 100
 101   // ArgFlags.isSplit() is true on the first part of a i128 argument;
 102   // PendingMembers.empty() is false on all subsequent parts.
 103   if (!ArgFlags.isSplit() && PendingMembers.empty())
 104     return false;
 105
 106   // Push a pending Indirect value location for each part.
 107   LocVT = MVT::i64;
 108   LocInfo = CCValAssign::Indirect;
 109   PendingMembers.push_back(CCValAssign::getPending(ValNo, ValVT,
 110                                                    LocVT, LocInfo));
 111   if (!ArgFlags.isSplitEnd())
 112     return true;
 113
 114   // OK, we've collected all parts in the pending list.  Allocate
 115   // the location (register or stack slot) for the indirect pointer.
 116   // (This duplicates the usual i64 calling convention rules.)
 117   unsigned Reg;
 118   const SystemZSubtarget &Subtarget =
 119       State.getMachineFunction().getSubtarget<SystemZSubtarget>();
 120   if (Subtarget.isTargetELF())
 121     Reg = State.AllocateReg(SystemZ::ELFArgGPRs);
 122   else if (Subtarget.isTargetXPLINK64())
 123     Reg = State.AllocateReg(SystemZ::XPLINK64ArgGPRs);
 124   else
 125     llvm_unreachable("Unknown Calling Convention!");
 126
 127   unsigned Offset = Reg && !Subtarget.isTargetXPLINK64()
 128                         ? 0
 129                         : State.AllocateStack(8, Align(8));
 130
 131   // Use that same location for all the pending parts.
 132   for (auto &It : PendingMembers) {
 133     if (Reg)
 134       It.convertToReg(Reg);
 135     else
 136       It.convertToMem(Offset);
 137     State.addLoc(It);
 138   }
 139
 140   PendingMembers.clear();
 141
 142   return true;
 143 }
 144
 145 // A pointer in 64bit mode is always passed as 64bit.
 146 inline bool CC_XPLINK64_Pointer(unsigned &ValNo, MVT &ValVT, MVT &LocVT,
 147                                 CCValAssign::LocInfo &LocInfo,
 148                                 ISD::ArgFlagsTy &ArgFlags, CCState &State) {
 149   if (LocVT != MVT::i64) {
 150     LocVT = MVT::i64;
 151     LocInfo = CCValAssign::ZExt;
 152   }
 153   return false;
 154 }
 155
 156 inline bool CC_XPLINK64_Shadow_Reg(unsigned &ValNo, MVT &ValVT, MVT &LocVT,
 157                                    CCValAssign::LocInfo &LocInfo,
 158                                    ISD::ArgFlagsTy &ArgFlags, CCState &State) {
 159   if (LocVT == MVT::f32 || LocVT == MVT::f64) {
 160     State.AllocateReg(SystemZ::XPLINK64ArgGPRs);
 161   }
 162   if (LocVT == MVT::f128 || LocVT.is128BitVector()) {
 163     // Shadow next two GPRs, if available.
 164     State.AllocateReg(SystemZ::XPLINK64ArgGPRs);
 165     State.AllocateReg(SystemZ::XPLINK64ArgGPRs);
 166
 167     // Quad precision floating point needs to
 168     // go inside pre-defined FPR pair.
 169     if (LocVT == MVT::f128) {
 170       for (unsigned I = 0; I < SystemZ::XPLINK64NumArgFPRs; I += 2)
 171         if (State.isAllocated(SystemZ::XPLINK64ArgFPRs[I]))
 172           State.AllocateReg(SystemZ::XPLINK64ArgFPRs[I + 1]);
 173     }
 174   }
 175   return false;
 176 }
 177
 178 inline bool CC_XPLINK64_Allocate128BitVararg(unsigned &ValNo, MVT &ValVT,
 179                                              MVT &LocVT,
 180                                              CCValAssign::LocInfo &LocInfo,
 181                                              ISD::ArgFlagsTy &ArgFlags,
 182                                              CCState &State) {
 183   // For any C or C++ program, this should always be
 184   // false, since it is illegal to have a function
 185   // where the first argument is variadic. Therefore
 186   // the first fixed argument should already have
 187   // allocated GPR1 either through shadowing it or
 188   // using it for parameter passing.
 189   State.AllocateReg(SystemZ::R1D);
 190
 191   bool AllocGPR2 = State.AllocateReg(SystemZ::R2D);
 192   bool AllocGPR3 = State.AllocateReg(SystemZ::R3D);
 193
 194   // If GPR2 and GPR3 are available, then we may pass vararg in R2Q.
 195   // If only GPR3 is available, we need to set custom handling to copy
 196   // hi bits into GPR3.
 197   // Either way, we allocate on the stack.
 198   if (AllocGPR3) {
 199     // For f128 and vector var arg case, set the bitcast flag to bitcast to
 200     // i128.
 201     LocVT = MVT::i128;
 202     LocInfo = CCValAssign::BCvt;
 203     auto Offset = State.AllocateStack(16, Align(8));
 204     if (AllocGPR2)
 205       State.addLoc(
 206           CCValAssign::getReg(ValNo, ValVT, SystemZ::R2Q, LocVT, LocInfo));
 207     else
 208       State.addLoc(
 209           CCValAssign::getCustomMem(ValNo, ValVT, Offset, LocVT, LocInfo));
 210     return true;
 211   }
 212
 213   return false;
 214 }
 215
 216 inline bool RetCC_SystemZ_Error(unsigned &, MVT &, MVT &,
 217                                 CCValAssign::LocInfo &, ISD::ArgFlagsTy &,
 218                                 CCState &) {
 219   llvm_unreachable("Return value calling convention currently unsupported.");
 220 }
 221
 222 inline bool CC_SystemZ_Error(unsigned &, MVT &, MVT &, CCValAssign::LocInfo &,
 223                              ISD::ArgFlagsTy &, CCState &) {
 224   llvm_unreachable("Argument calling convention currently unsupported.");
 225 }
 226
 227 inline bool CC_SystemZ_GHC_Error(unsigned &, MVT &, MVT &,
 228                                  CCValAssign::LocInfo &, ISD::ArgFlagsTy &,
 229                                  CCState &) {
 230   report_fatal_error("No registers left in GHC calling convention");
 231   return false;
 232 }
 233
 234 } // end namespace llvm
 235
 236 #endif