CallingConvLower.cpp revision a50760f43bafbb46f72fc22426075204a69ce178 
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"
24using namespace llvm;
25
26CCState::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.
42void 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.
60void 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.
68void
69CCState::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.
88bool 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.
102void 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.
120void 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.
138void 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.
157void 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.
174void 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}
183