CallingConvLower.cpp revision af52ee40fb60099ddec2b896aa4c759ef05b70c8 
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"
22using namespace llvm;
23
24CCState::CCState(CallingConv::ID CC, bool isVarArg, const TargetMachine &tm,
25                 SmallVector<CCValAssign, 16> &locs, LLVMContext &C)
26  : CallingConv(CC), IsVarArg(isVarArg), TM(tm),
27    TRI(*TM.getRegisterInfo()), Locs(locs), Context(C) {
28  // No stack is used.
29  StackOffset = 0;
30
31  UsedRegs.resize((TRI.getNumRegs()+31)/32);
32}
33
34// HandleByVal - Allocate a stack slot large enough to pass an argument by
35// value. The size and alignment information of the argument is encoded in its
36// parameter attribute.
37void CCState::HandleByVal(unsigned ValNo, EVT ValVT,
38                          EVT LocVT, CCValAssign::LocInfo LocInfo,
39                          int MinSize, int MinAlign,
40                          ISD::ArgFlagsTy ArgFlags) {
41  unsigned Align = ArgFlags.getByValAlign();
42  unsigned Size  = ArgFlags.getByValSize();
43  if (MinSize > (int)Size)
44    Size = MinSize;
45  if (MinAlign > (int)Align)
46    Align = MinAlign;
47  unsigned Offset = AllocateStack(Size, Align);
48
49  addLoc(CCValAssign::getMem(ValNo, ValVT, Offset, LocVT, LocInfo));
50}
51
52/// MarkAllocated - Mark a register and all of its aliases as allocated.
53void CCState::MarkAllocated(unsigned Reg) {
54  UsedRegs[Reg/32] |= 1 << (Reg&31);
55
56  if (const unsigned *RegAliases = TRI.getAliasSet(Reg))
57    for (; (Reg = *RegAliases); ++RegAliases)
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.
63void
64CCState::AnalyzeFormalArguments(const SmallVectorImpl<ISD::InputArg> &Ins,
65                                CCAssignFn Fn) {
66  unsigned NumArgs = Ins.size();
67
68  for (unsigned i = 0; i != NumArgs; ++i) {
69    EVT 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             << 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.
83bool CCState::CheckReturn(const SmallVectorImpl<EVT> &OutTys,
84                          const SmallVectorImpl<ISD::ArgFlagsTy> &ArgsFlags,
85                          CCAssignFn Fn) {
86  // Determine which register each value should be copied into.
87  for (unsigned i = 0, e = OutTys.size(); i != e; ++i) {
88    EVT VT = OutTys[i];
89    ISD::ArgFlagsTy ArgFlags = ArgsFlags[i];
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.
98void 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    EVT 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             << 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.
116void CCState::AnalyzeCallOperands(const SmallVectorImpl<ISD::OutputArg> &Outs,
117                                  CCAssignFn Fn) {
118  unsigned NumOps = Outs.size();
119  for (unsigned i = 0; i != NumOps; ++i) {
120    EVT 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             << 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.
134void CCState::AnalyzeCallOperands(SmallVectorImpl<EVT> &ArgVTs,
135                                  SmallVectorImpl<ISD::ArgFlagsTy> &Flags,
136                                  CCAssignFn Fn) {
137  unsigned NumOps = ArgVTs.size();
138  for (unsigned i = 0; i != NumOps; ++i) {
139    EVT 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             << 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.
153void CCState::AnalyzeCallResult(const SmallVectorImpl<ISD::InputArg> &Ins,
154                                CCAssignFn Fn) {
155  for (unsigned i = 0, e = Ins.size(); i != e; ++i) {
156    EVT 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             << VT.getEVTString();
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.
170void CCState::AnalyzeCallResult(EVT 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           << VT.getEVTString();
175#endif
176    llvm_unreachable(0);
177  }
178}
179