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/IR/DataLayout.h"
18#include "llvm/Support/Debug.h"
19#include "llvm/Support/ErrorHandling.h"
20#include "llvm/Support/raw_ostream.h"
21#include "llvm/Target/TargetLowering.h"
22#include "llvm/Target/TargetMachine.h"
23#include "llvm/Target/TargetRegisterInfo.h"
24using namespace llvm;
25
26CCState::CCState(CallingConv::ID CC, bool isVarArg, MachineFunction &mf,
27                 const TargetMachine &tm, SmallVectorImpl<CCValAssign> &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  clearByValRegsInfo();
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  MF.getFrameInfo()->ensureMaxAlignment(Align);
53  TM.getTargetLowering()->HandleByVal(this, Size, Align);
54  unsigned Offset = AllocateStack(Size, Align);
55  addLoc(CCValAssign::getMem(ValNo, ValVT, Offset, LocVT, LocInfo));
56}
57
58/// MarkAllocated - Mark a register and all of its aliases as allocated.
59void CCState::MarkAllocated(unsigned Reg) {
60  for (MCRegAliasIterator AI(Reg, &TRI, true); AI.isValid(); ++AI)
61    UsedRegs[*AI/32] |= 1 << (*AI&31);
62}
63
64/// AnalyzeFormalArguments - Analyze an array of argument values,
65/// incorporating info about the formals into this state.
66void
67CCState::AnalyzeFormalArguments(const SmallVectorImpl<ISD::InputArg> &Ins,
68                                CCAssignFn Fn) {
69  unsigned NumArgs = Ins.size();
70
71  for (unsigned i = 0; i != NumArgs; ++i) {
72    MVT ArgVT = Ins[i].VT;
73    ISD::ArgFlagsTy ArgFlags = Ins[i].Flags;
74    if (Fn(i, ArgVT, ArgVT, CCValAssign::Full, ArgFlags, *this)) {
75#ifndef NDEBUG
76      dbgs() << "Formal argument #" << i << " has unhandled type "
77             << EVT(ArgVT).getEVTString() << '\n';
78#endif
79      llvm_unreachable(nullptr);
80    }
81  }
82}
83
84/// CheckReturn - Analyze the return values of a function, returning true if
85/// the return can be performed without sret-demotion, and false otherwise.
86bool CCState::CheckReturn(const SmallVectorImpl<ISD::OutputArg> &Outs,
87                          CCAssignFn Fn) {
88  // Determine which register each value should be copied into.
89  for (unsigned i = 0, e = Outs.size(); i != e; ++i) {
90    MVT VT = Outs[i].VT;
91    ISD::ArgFlagsTy ArgFlags = Outs[i].Flags;
92    if (Fn(i, VT, VT, CCValAssign::Full, ArgFlags, *this))
93      return false;
94  }
95  return true;
96}
97
98/// AnalyzeReturn - Analyze the returned values of a return,
99/// incorporating info about the result values into this state.
100void CCState::AnalyzeReturn(const SmallVectorImpl<ISD::OutputArg> &Outs,
101                            CCAssignFn Fn) {
102  // Determine which register each value should be copied into.
103  for (unsigned i = 0, e = Outs.size(); i != e; ++i) {
104    MVT VT = Outs[i].VT;
105    ISD::ArgFlagsTy ArgFlags = Outs[i].Flags;
106    if (Fn(i, VT, VT, CCValAssign::Full, ArgFlags, *this)) {
107#ifndef NDEBUG
108      dbgs() << "Return operand #" << i << " has unhandled type "
109             << EVT(VT).getEVTString() << '\n';
110#endif
111      llvm_unreachable(nullptr);
112    }
113  }
114}
115
116/// AnalyzeCallOperands - Analyze the outgoing arguments to a call,
117/// incorporating info about the passed values into this state.
118void CCState::AnalyzeCallOperands(const SmallVectorImpl<ISD::OutputArg> &Outs,
119                                  CCAssignFn Fn) {
120  unsigned NumOps = Outs.size();
121  for (unsigned i = 0; i != NumOps; ++i) {
122    MVT ArgVT = Outs[i].VT;
123    ISD::ArgFlagsTy ArgFlags = Outs[i].Flags;
124    if (Fn(i, ArgVT, ArgVT, CCValAssign::Full, ArgFlags, *this)) {
125#ifndef NDEBUG
126      dbgs() << "Call operand #" << i << " has unhandled type "
127             << EVT(ArgVT).getEVTString() << '\n';
128#endif
129      llvm_unreachable(nullptr);
130    }
131  }
132}
133
134/// AnalyzeCallOperands - Same as above except it takes vectors of types
135/// and argument flags.
136void CCState::AnalyzeCallOperands(SmallVectorImpl<MVT> &ArgVTs,
137                                  SmallVectorImpl<ISD::ArgFlagsTy> &Flags,
138                                  CCAssignFn Fn) {
139  unsigned NumOps = ArgVTs.size();
140  for (unsigned i = 0; i != NumOps; ++i) {
141    MVT ArgVT = ArgVTs[i];
142    ISD::ArgFlagsTy ArgFlags = Flags[i];
143    if (Fn(i, ArgVT, ArgVT, CCValAssign::Full, ArgFlags, *this)) {
144#ifndef NDEBUG
145      dbgs() << "Call operand #" << i << " has unhandled type "
146             << EVT(ArgVT).getEVTString() << '\n';
147#endif
148      llvm_unreachable(nullptr);
149    }
150  }
151}
152
153/// AnalyzeCallResult - Analyze the return values of a call,
154/// incorporating info about the passed values into this state.
155void CCState::AnalyzeCallResult(const SmallVectorImpl<ISD::InputArg> &Ins,
156                                CCAssignFn Fn) {
157  for (unsigned i = 0, e = Ins.size(); i != e; ++i) {
158    MVT VT = Ins[i].VT;
159    ISD::ArgFlagsTy Flags = Ins[i].Flags;
160    if (Fn(i, VT, VT, CCValAssign::Full, Flags, *this)) {
161#ifndef NDEBUG
162      dbgs() << "Call result #" << i << " has unhandled type "
163             << EVT(VT).getEVTString() << '\n';
164#endif
165      llvm_unreachable(nullptr);
166    }
167  }
168}
169
170/// AnalyzeCallResult - Same as above except it's specialized for calls which
171/// produce a single value.
172void CCState::AnalyzeCallResult(MVT VT, CCAssignFn Fn) {
173  if (Fn(0, VT, VT, CCValAssign::Full, ISD::ArgFlagsTy(), *this)) {
174#ifndef NDEBUG
175    dbgs() << "Call result has unhandled type "
176           << EVT(VT).getEVTString() << '\n';
177#endif
178    llvm_unreachable(nullptr);
179  }
180}
181