lib/CodeGen/CallingConvLower.cpp

   1 //===-- CallingConvLower.cpp - Calling Conventions ------------------------===//
   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 // This file implements the CCState class, used for lowering and implementing
  11 // calling conventions.
  12 //
  13 //===----------------------------------------------------------------------===//
  14
  15 #include "llvm/CodeGen/CallingConvLower.h"
  16 #include "llvm/Support/Debug.h"
  17 #include "llvm/Support/ErrorHandling.h"
  18 #include "llvm/Support/raw_ostream.h"
  19 #include "llvm/Target/TargetRegisterInfo.h"
  20 #include "llvm/Target/TargetData.h"
  21 #include "llvm/Target/TargetMachine.h"
  22 #include "llvm/Target/TargetLowering.h"
  23 using namespace llvm;
  24
  25 CCState::CCState(CallingConv::ID CC, bool isVarArg, const TargetMachine &tm,
  26                  SmallVector<CCValAssign, 16> &locs, LLVMContext &C)
  27   : CallingConv(CC), IsVarArg(isVarArg), TM(tm),
  28     TRI(*TM.getRegisterInfo()), Locs(locs), Context(C) {
  29   // No stack is used.
  30   StackOffset = 0;
  31
  32   UsedRegs.resize((TRI.getNumRegs()+31)/32);
  33 }
  34
  35 // HandleByVal - Allocate a stack slot large enough to pass an argument by
  36 // value. The size and alignment information of the argument is encoded in its
  37 // parameter attribute.
  38 void CCState::HandleByVal(unsigned ValNo, MVT ValVT,
  39                           MVT LocVT, CCValAssign::LocInfo LocInfo,
  40                           int MinSize, int MinAlign,
  41                           ISD::ArgFlagsTy ArgFlags) {
  42   unsigned Align = ArgFlags.getByValAlign();
  43   unsigned Size  = ArgFlags.getByValSize();
  44   if (MinSize > (int)Size)
  45     Size = MinSize;
  46   if (MinAlign > (int)Align)
  47     Align = MinAlign;
  48   unsigned Offset = AllocateStack(Size, Align);
  49
  50   addLoc(CCValAssign::getMem(ValNo, ValVT, Offset, LocVT, LocInfo));
  51   TM.getTargetLowering()->HandleByVal(const_cast<CCState*>(this));
  52 }
  53
  54 /// MarkAllocated - Mark a register and all of its aliases as allocated.
  55 void CCState::MarkAllocated(unsigned Reg) {
  56   for (const unsigned *Alias = TRI.getOverlaps(Reg);
  57        unsigned Reg = *Alias; ++Alias)
  58     UsedRegs[Reg/32] |= 1 << (Reg&31);
  59 }
  60
  61 /// AnalyzeFormalArguments - Analyze an array of argument values,
  62 /// incorporating info about the formals into this state.
  63 void
  64 CCState::AnalyzeFormalArguments(const SmallVectorImpl<ISD::InputArg> &Ins,
  65                                 CCAssignFn Fn) {
  66   unsigned NumArgs = Ins.size();
  67
  68   for (unsigned i = 0; i != NumArgs; ++i) {
  69     MVT ArgVT = Ins[i].VT;
  70     ISD::ArgFlagsTy ArgFlags = Ins[i].Flags;
  71     if (Fn(i, ArgVT, ArgVT, CCValAssign::Full, ArgFlags, *this)) {
  72 #ifndef NDEBUG
  73       dbgs() << "Formal argument #" << i << " has unhandled type "
  74              << EVT(ArgVT).getEVTString();
  75 #endif
  76       llvm_unreachable(0);
  77     }
  78   }
  79 }
  80
  81 /// CheckReturn - Analyze the return values of a function, returning true if
  82 /// the return can be performed without sret-demotion, and false otherwise.
  83 bool CCState::CheckReturn(const SmallVectorImpl<ISD::OutputArg> &Outs,
  84                           CCAssignFn Fn) {
  85   // Determine which register each value should be copied into.
  86   for (unsigned i = 0, e = Outs.size(); i != e; ++i) {
  87     MVT VT = Outs[i].VT;
  88     ISD::ArgFlagsTy ArgFlags = Outs[i].Flags;
  89     if (Fn(i, VT, VT, CCValAssign::Full, ArgFlags, *this))
  90       return false;
  91   }
  92   return true;
  93 }
  94
  95 /// AnalyzeReturn - Analyze the returned values of a return,
  96 /// incorporating info about the result values into this state.
  97 void CCState::AnalyzeReturn(const SmallVectorImpl<ISD::OutputArg> &Outs,
  98                             CCAssignFn Fn) {
  99   // Determine which register each value should be copied into.
 100   for (unsigned i = 0, e = Outs.size(); i != e; ++i) {
 101     MVT VT = Outs[i].VT;
 102     ISD::ArgFlagsTy ArgFlags = Outs[i].Flags;
 103     if (Fn(i, VT, VT, CCValAssign::Full, ArgFlags, *this)) {
 104 #ifndef NDEBUG
 105       dbgs() << "Return operand #" << i << " has unhandled type "
 106              << EVT(VT).getEVTString();
 107 #endif
 108       llvm_unreachable(0);
 109     }
 110   }
 111 }
 112
 113 /// AnalyzeCallOperands - Analyze the outgoing arguments to a call,
 114 /// incorporating info about the passed values into this state.
 115 void CCState::AnalyzeCallOperands(const SmallVectorImpl<ISD::OutputArg> &Outs,
 116                                   CCAssignFn Fn) {
 117   unsigned NumOps = Outs.size();
 118   for (unsigned i = 0; i != NumOps; ++i) {
 119     MVT ArgVT = Outs[i].VT;
 120     ISD::ArgFlagsTy ArgFlags = Outs[i].Flags;
 121     if (Fn(i, ArgVT, ArgVT, CCValAssign::Full, ArgFlags, *this)) {
 122 #ifndef NDEBUG
 123       dbgs() << "Call operand #" << i << " has unhandled type "
 124              << EVT(ArgVT).getEVTString();
 125 #endif
 126       llvm_unreachable(0);
 127     }
 128   }
 129 }
 130
 131 /// AnalyzeCallOperands - Same as above except it takes vectors of types
 132 /// and argument flags.
 133 void CCState::AnalyzeCallOperands(SmallVectorImpl<MVT> &ArgVTs,
 134                                   SmallVectorImpl<ISD::ArgFlagsTy> &Flags,
 135                                   CCAssignFn Fn) {
 136   unsigned NumOps = ArgVTs.size();
 137   for (unsigned i = 0; i != NumOps; ++i) {
 138     MVT ArgVT = ArgVTs[i];
 139     ISD::ArgFlagsTy ArgFlags = Flags[i];
 140     if (Fn(i, ArgVT, ArgVT, CCValAssign::Full, ArgFlags, *this)) {
 141 #ifndef NDEBUG
 142       dbgs() << "Call operand #" << i << " has unhandled type "
 143              << EVT(ArgVT).getEVTString();
 144 #endif
 145       llvm_unreachable(0);
 146     }
 147   }
 148 }
 149
 150 /// AnalyzeCallResult - Analyze the return values of a call,
 151 /// incorporating info about the passed values into this state.
 152 void CCState::AnalyzeCallResult(const SmallVectorImpl<ISD::InputArg> &Ins,
 153                                 CCAssignFn Fn) {
 154   for (unsigned i = 0, e = Ins.size(); i != e; ++i) {
 155     MVT VT = Ins[i].VT;
 156     ISD::ArgFlagsTy Flags = Ins[i].Flags;
 157     if (Fn(i, VT, VT, CCValAssign::Full, Flags, *this)) {
 158 #ifndef NDEBUG
 159       dbgs() << "Call result #" << i << " has unhandled type "
 160              << EVT(VT).getEVTString() << "\n";
 161 #endif
 162       llvm_unreachable(0);
 163     }
 164   }
 165 }
 166
 167 /// AnalyzeCallResult - Same as above except it's specialized for calls which
 168 /// produce a single value.
 169 void CCState::AnalyzeCallResult(MVT VT, CCAssignFn Fn) {
 170   if (Fn(0, VT, VT, CCValAssign::Full, ISD::ArgFlagsTy(), *this)) {
 171 #ifndef NDEBUG
 172     dbgs() << "Call result has unhandled type "
 173            << EVT(VT).getEVTString();
 174 #endif
 175     llvm_unreachable(0);
 176   }
 177 }