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