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      1 //===-- SystemZCallingConv.h - Calling conventions for SystemZ --*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 
     10 #ifndef LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZCALLINGCONV_H
     11 #define LLVM_LIB_TARGET_SYSTEMZ_SYSTEMZCALLINGCONV_H
     12 
     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 NumArgGPRs = 5;
     20   extern const MCPhysReg ArgGPRs[NumArgGPRs];
     21 
     22   const unsigned NumArgFPRs = 4;
     23   extern const MCPhysReg ArgFPRs[NumArgFPRs];
     24 } // end namespace SystemZ
     25 
     26 class SystemZCCState : public CCState {
     27 private:
     28   /// Records whether the value was a fixed argument.
     29   /// See ISD::OutputArg::IsFixed.
     30   SmallVector<bool, 4> ArgIsFixed;
     31 
     32   /// Records whether the value was widened from a short vector type.
     33   SmallVector<bool, 4> ArgIsShortVector;
     34 
     35   // Check whether ArgVT is a short vector type.
     36   bool IsShortVectorType(EVT ArgVT) {
     37     return ArgVT.isVector() && ArgVT.getStoreSize() <= 8;
     38   }
     39 
     40 public:
     41   SystemZCCState(CallingConv::ID CC, bool isVarArg, MachineFunction &MF,
     42                  SmallVectorImpl<CCValAssign> &locs, LLVMContext &C)
     43       : CCState(CC, isVarArg, MF, locs, C) {}
     44 
     45   void AnalyzeFormalArguments(const SmallVectorImpl<ISD::InputArg> &Ins,
     46                               CCAssignFn Fn) {
     47     // Formal arguments are always fixed.
     48     ArgIsFixed.clear();
     49     for (unsigned i = 0; i < Ins.size(); ++i)
     50       ArgIsFixed.push_back(true);
     51     // Record whether the call operand was a short vector.
     52     ArgIsShortVector.clear();
     53     for (unsigned i = 0; i < Ins.size(); ++i)
     54       ArgIsShortVector.push_back(IsShortVectorType(Ins[i].ArgVT));
     55 
     56     CCState::AnalyzeFormalArguments(Ins, Fn);
     57   }
     58 
     59   void AnalyzeCallOperands(const SmallVectorImpl<ISD::OutputArg> &Outs,
     60                            CCAssignFn Fn) {
     61     // Record whether the call operand was a fixed argument.
     62     ArgIsFixed.clear();
     63     for (unsigned i = 0; i < Outs.size(); ++i)
     64       ArgIsFixed.push_back(Outs[i].IsFixed);
     65     // Record whether the call operand was a short vector.
     66     ArgIsShortVector.clear();
     67     for (unsigned i = 0; i < Outs.size(); ++i)
     68       ArgIsShortVector.push_back(IsShortVectorType(Outs[i].ArgVT));
     69 
     70     CCState::AnalyzeCallOperands(Outs, Fn);
     71   }
     72 
     73   // This version of AnalyzeCallOperands in the base class is not usable
     74   // since we must provide a means of accessing ISD::OutputArg::IsFixed.
     75   void AnalyzeCallOperands(const SmallVectorImpl<MVT> &Outs,
     76                            SmallVectorImpl<ISD::ArgFlagsTy> &Flags,
     77                            CCAssignFn Fn) = delete;
     78 
     79   bool IsFixed(unsigned ValNo) { return ArgIsFixed[ValNo]; }
     80   bool IsShortVector(unsigned ValNo) { return ArgIsShortVector[ValNo]; }
     81 };
     82 
     83 // Handle i128 argument types.  These need to be passed by implicit
     84 // reference.  This could be as simple as the following .td line:
     85 //    CCIfType<[i128], CCPassIndirect<i64>>,
     86 // except that i128 is not a legal type, and therefore gets split by
     87 // common code into a pair of i64 arguments.
     88 inline bool CC_SystemZ_I128Indirect(unsigned &ValNo, MVT &ValVT,
     89                                     MVT &LocVT,
     90                                     CCValAssign::LocInfo &LocInfo,
     91                                     ISD::ArgFlagsTy &ArgFlags,
     92                                     CCState &State) {
     93   SmallVectorImpl<CCValAssign> &PendingMembers = State.getPendingLocs();
     94 
     95   // ArgFlags.isSplit() is true on the first part of a i128 argument;
     96   // PendingMembers.empty() is false on all subsequent parts.
     97   if (!ArgFlags.isSplit() && PendingMembers.empty())
     98     return false;
     99 
    100   // Push a pending Indirect value location for each part.
    101   LocVT = MVT::i64;
    102   LocInfo = CCValAssign::Indirect;
    103   PendingMembers.push_back(CCValAssign::getPending(ValNo, ValVT,
    104                                                    LocVT, LocInfo));
    105   if (!ArgFlags.isSplitEnd())
    106     return true;
    107 
    108   // OK, we've collected all parts in the pending list.  Allocate
    109   // the location (register or stack slot) for the indirect pointer.
    110   // (This duplicates the usual i64 calling convention rules.)
    111   unsigned Reg = State.AllocateReg(SystemZ::ArgGPRs);
    112   unsigned Offset = Reg ? 0 : State.AllocateStack(8, 8);
    113 
    114   // Use that same location for all the pending parts.
    115   for (auto &It : PendingMembers) {
    116     if (Reg)
    117       It.convertToReg(Reg);
    118     else
    119       It.convertToMem(Offset);
    120     State.addLoc(It);
    121   }
    122 
    123   PendingMembers.clear();
    124 
    125   return true;
    126 }
    127 
    128 } // end namespace llvm
    129 
    130 #endif
    131