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/CodeGen/MachineFrameInfo.h"
  17 #include "llvm/Support/Debug.h"
  18 #include "llvm/Support/ErrorHandling.h"
  19 #include "llvm/Support/raw_ostream.h"
  20 #include "llvm/Target/TargetRegisterInfo.h"
  21 #include "llvm/Target/TargetData.h"
  22 #include "llvm/Target/TargetMachine.h"
  23 #include "llvm/Target/TargetLowering.h"
  24 using namespace llvm;
  25
  26 CCState::CCState(CallingConv::ID CC, bool isVarArg, MachineFunction &mf,
  27                  const TargetMachine &tm, SmallVector<CCValAssign, 16> &locs,
  28                  LLVMContext &C)
  29   : CallingConv(CC), IsVarArg(isVarArg), MF(mf), TM(tm),
  30     TRI(*TM.getRegisterInfo()), Locs(locs), Context(C),
  31     CallOrPrologue(Unknown) {
  32   // No stack is used.
  33   StackOffset = 0;
  34
  35   clearFirstByValReg();
  36   UsedRegs.resize((TRI.getNumRegs()+31)/32);
  37 }
  38
  39 // HandleByVal - Allocate space on the stack large enough to pass an argument
  40 // by value. The size and alignment information of the argument is encoded in
  41 // its parameter attribute.
  42 void CCState::HandleByVal(unsigned ValNo, MVT ValVT,
  43                           MVT LocVT, CCValAssign::LocInfo LocInfo,
  44                           int MinSize, int MinAlign,
  45                           ISD::ArgFlagsTy ArgFlags) {
  46   unsigned Align = ArgFlags.getByValAlign();
  47   unsigned Size  = ArgFlags.getByValSize();
  48   if (MinSize > (int)Size)
  49     Size = MinSize;
  50   if (MinAlign > (int)Align)
  51     Align = MinAlign;
  52   if (MF.getFrameInfo()->getMaxAlignment() < Align)
  53     MF.getFrameInfo()->setMaxAlignment(Align);
  54   TM.getTargetLowering()->HandleByVal(this, Size);
  55   unsigned Offset = AllocateStack(Size, Align);
  56   addLoc(CCValAssign::getMem(ValNo, ValVT, Offset, LocVT, LocInfo));
  57 }
  58
  59 /// MarkAllocated - Mark a register and all of its aliases as allocated.
  60 void CCState::MarkAllocated(unsigned Reg) {
  61   for (const unsigned *Alias = TRI.getOverlaps(Reg);
  62        unsigned Reg = *Alias; ++Alias)
  63     UsedRegs[Reg/32] |= 1 << (Reg&31);
  64 }
  65
  66 /// AnalyzeFormalArguments - Analyze an array of argument values,
  67 /// incorporating info about the formals into this state.
  68 void
  69 CCState::AnalyzeFormalArguments(const SmallVectorImpl<ISD::InputArg> &Ins,
  70                                 CCAssignFn Fn) {
  71   unsigned NumArgs = Ins.size();
  72
  73   for (unsigned i = 0; i != NumArgs; ++i) {
  74     MVT ArgVT = Ins[i].VT;
  75     ISD::ArgFlagsTy ArgFlags = Ins[i].Flags;
  76     if (Fn(i, ArgVT, ArgVT, CCValAssign::Full, ArgFlags, *this)) {
  77 #ifndef NDEBUG
  78       dbgs() << "Formal argument #" << i << " has unhandled type "
  79              << EVT(ArgVT).getEVTString();
  80 #endif
  81       llvm_unreachable(0);
  82     }
  83   }
  84 }
  85
  86 /// CheckReturn - Analyze the return values of a function, returning true if
  87 /// the return can be performed without sret-demotion, and false otherwise.
  88 bool CCState::CheckReturn(const SmallVectorImpl<ISD::OutputArg> &Outs,
  89                           CCAssignFn Fn) {
  90   // Determine which register each value should be copied into.
  91   for (unsigned i = 0, e = Outs.size(); i != e; ++i) {
  92     MVT VT = Outs[i].VT;
  93     ISD::ArgFlagsTy ArgFlags = Outs[i].Flags;
  94     if (Fn(i, VT, VT, CCValAssign::Full, ArgFlags, *this))
  95       return false;
  96   }
  97   return true;
  98 }
  99
 100 /// AnalyzeReturn - Analyze the returned values of a return,
 101 /// incorporating info about the result values into this state.
 102 void CCState::AnalyzeReturn(const SmallVectorImpl<ISD::OutputArg> &Outs,
 103                             CCAssignFn Fn) {
 104   // Determine which register each value should be copied into.
 105   for (unsigned i = 0, e = Outs.size(); i != e; ++i) {
 106     MVT VT = Outs[i].VT;
 107     ISD::ArgFlagsTy ArgFlags = Outs[i].Flags;
 108     if (Fn(i, VT, VT, CCValAssign::Full, ArgFlags, *this)) {
 109 #ifndef NDEBUG
 110       dbgs() << "Return operand #" << i << " has unhandled type "
 111              << EVT(VT).getEVTString();
 112 #endif
 113       llvm_unreachable(0);
 114     }
 115   }
 116 }
 117
 118 /// AnalyzeCallOperands - Analyze the outgoing arguments to a call,
 119 /// incorporating info about the passed values into this state.
 120 void CCState::AnalyzeCallOperands(const SmallVectorImpl<ISD::OutputArg> &Outs,
 121                                   CCAssignFn Fn) {
 122   unsigned NumOps = Outs.size();
 123   for (unsigned i = 0; i != NumOps; ++i) {
 124     MVT ArgVT = Outs[i].VT;
 125     ISD::ArgFlagsTy ArgFlags = Outs[i].Flags;
 126     if (Fn(i, ArgVT, ArgVT, CCValAssign::Full, ArgFlags, *this)) {
 127 #ifndef NDEBUG
 128       dbgs() << "Call operand #" << i << " has unhandled type "
 129              << EVT(ArgVT).getEVTString();
 130 #endif
 131       llvm_unreachable(0);
 132     }
 133   }
 134 }
 135
 136 /// AnalyzeCallOperands - Same as above except it takes vectors of types
 137 /// and argument flags.
 138 void CCState::AnalyzeCallOperands(SmallVectorImpl<MVT> &ArgVTs,
 139                                   SmallVectorImpl<ISD::ArgFlagsTy> &Flags,
 140                                   CCAssignFn Fn) {
 141   unsigned NumOps = ArgVTs.size();
 142   for (unsigned i = 0; i != NumOps; ++i) {
 143     MVT ArgVT = ArgVTs[i];
 144     ISD::ArgFlagsTy ArgFlags = Flags[i];
 145     if (Fn(i, ArgVT, ArgVT, CCValAssign::Full, ArgFlags, *this)) {
 146 #ifndef NDEBUG
 147       dbgs() << "Call operand #" << i << " has unhandled type "
 148              << EVT(ArgVT).getEVTString();
 149 #endif
 150       llvm_unreachable(0);
 151     }
 152   }
 153 }
 154
 155 /// AnalyzeCallResult - Analyze the return values of a call,
 156 /// incorporating info about the passed values into this state.
 157 void CCState::AnalyzeCallResult(const SmallVectorImpl<ISD::InputArg> &Ins,
 158                                 CCAssignFn Fn) {
 159   for (unsigned i = 0, e = Ins.size(); i != e; ++i) {
 160     MVT VT = Ins[i].VT;
 161     ISD::ArgFlagsTy Flags = Ins[i].Flags;
 162     if (Fn(i, VT, VT, CCValAssign::Full, Flags, *this)) {
 163 #ifndef NDEBUG
 164       dbgs() << "Call result #" << i << " has unhandled type "
 165              << EVT(VT).getEVTString() << "\n";
 166 #endif
 167       llvm_unreachable(0);
 168     }
 169   }
 170 }
 171
 172 /// AnalyzeCallResult - Same as above except it's specialized for calls which
 173 /// produce a single value.
 174 void CCState::AnalyzeCallResult(MVT VT, CCAssignFn Fn) {
 175   if (Fn(0, VT, VT, CCValAssign::Full, ISD::ArgFlagsTy(), *this)) {
 176 #ifndef NDEBUG
 177     dbgs() << "Call result has unhandled type "
 178            << EVT(VT).getEVTString();
 179 #endif
 180     llvm_unreachable(0);
 181   }
 182 }