1//===----- CGCall.h - Encapsulate calling convention details ----*- C++ -*-===//
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// These classes wrap the information about a call or function
11// definition used to handle ABI compliancy.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef CLANG_CODEGEN_CGCALL_H
16#define CLANG_CODEGEN_CGCALL_H
17
18#include "CGValue.h"
19#include "clang/AST/CanonicalType.h"
20#include "clang/AST/Type.h"
21#include "llvm/ADT/FoldingSet.h"
22#include "llvm/IR/Value.h"
23
24// FIXME: Restructure so we don't have to expose so much stuff.
25#include "ABIInfo.h"
26
27namespace llvm {
28  class AttributeSet;
29  class Function;
30  class Type;
31  class Value;
32}
33
34namespace clang {
35  class ASTContext;
36  class Decl;
37  class FunctionDecl;
38  class ObjCMethodDecl;
39  class VarDecl;
40
41namespace CodeGen {
42  typedef SmallVector<llvm::AttributeSet, 8> AttributeListType;
43
44  struct CallArg {
45    RValue RV;
46    QualType Ty;
47    bool NeedsCopy;
48    CallArg(RValue rv, QualType ty, bool needscopy)
49    : RV(rv), Ty(ty), NeedsCopy(needscopy)
50    { }
51  };
52
53  /// CallArgList - Type for representing both the value and type of
54  /// arguments in a call.
55  class CallArgList :
56    public SmallVector<CallArg, 16> {
57  public:
58    struct Writeback {
59      /// The original argument.
60      llvm::Value *Address;
61
62      /// The pointee type of the original argument.
63      QualType AddressType;
64
65      /// The temporary alloca.
66      llvm::Value *Temporary;
67    };
68
69    void add(RValue rvalue, QualType type, bool needscopy = false) {
70      push_back(CallArg(rvalue, type, needscopy));
71    }
72
73    void addFrom(const CallArgList &other) {
74      insert(end(), other.begin(), other.end());
75      Writebacks.insert(Writebacks.end(),
76                        other.Writebacks.begin(), other.Writebacks.end());
77    }
78
79    void addWriteback(llvm::Value *address, QualType addressType,
80                      llvm::Value *temporary) {
81      Writeback writeback;
82      writeback.Address = address;
83      writeback.AddressType = addressType;
84      writeback.Temporary = temporary;
85      Writebacks.push_back(writeback);
86    }
87
88    bool hasWritebacks() const { return !Writebacks.empty(); }
89
90    typedef SmallVectorImpl<Writeback>::const_iterator writeback_iterator;
91    writeback_iterator writeback_begin() const { return Writebacks.begin(); }
92    writeback_iterator writeback_end() const { return Writebacks.end(); }
93
94  private:
95    SmallVector<Writeback, 1> Writebacks;
96  };
97
98  /// A class for recording the number of arguments that a function
99  /// signature requires.
100  class RequiredArgs {
101    /// The number of required arguments, or ~0 if the signature does
102    /// not permit optional arguments.
103    unsigned NumRequired;
104  public:
105    enum All_t { All };
106
107    RequiredArgs(All_t _) : NumRequired(~0U) {}
108    explicit RequiredArgs(unsigned n) : NumRequired(n) {
109      assert(n != ~0U);
110    }
111
112    /// Compute the arguments required by the given formal prototype,
113    /// given that there may be some additional, non-formal arguments
114    /// in play.
115    static RequiredArgs forPrototypePlus(const FunctionProtoType *prototype,
116                                         unsigned additional) {
117      if (!prototype->isVariadic()) return All;
118      return RequiredArgs(prototype->getNumArgs() + additional);
119    }
120
121    static RequiredArgs forPrototype(const FunctionProtoType *prototype) {
122      return forPrototypePlus(prototype, 0);
123    }
124
125    static RequiredArgs forPrototype(CanQual<FunctionProtoType> prototype) {
126      return forPrototype(prototype.getTypePtr());
127    }
128
129    static RequiredArgs forPrototypePlus(CanQual<FunctionProtoType> prototype,
130                                         unsigned additional) {
131      return forPrototypePlus(prototype.getTypePtr(), additional);
132    }
133
134    bool allowsOptionalArgs() const { return NumRequired != ~0U; }
135    unsigned getNumRequiredArgs() const {
136      assert(allowsOptionalArgs());
137      return NumRequired;
138    }
139
140    unsigned getOpaqueData() const { return NumRequired; }
141    static RequiredArgs getFromOpaqueData(unsigned value) {
142      if (value == ~0U) return All;
143      return RequiredArgs(value);
144    }
145  };
146
147  /// FunctionArgList - Type for representing both the decl and type
148  /// of parameters to a function. The decl must be either a
149  /// ParmVarDecl or ImplicitParamDecl.
150  class FunctionArgList : public SmallVector<const VarDecl*, 16> {
151  };
152
153  /// CGFunctionInfo - Class to encapsulate the information about a
154  /// function definition.
155  class CGFunctionInfo : public llvm::FoldingSetNode {
156    struct ArgInfo {
157      CanQualType type;
158      ABIArgInfo info;
159    };
160
161    /// The LLVM::CallingConv to use for this function (as specified by the
162    /// user).
163    unsigned CallingConvention : 8;
164
165    /// The LLVM::CallingConv to actually use for this function, which may
166    /// depend on the ABI.
167    unsigned EffectiveCallingConvention : 8;
168
169    /// The clang::CallingConv that this was originally created with.
170    unsigned ASTCallingConvention : 8;
171
172    /// Whether this function is noreturn.
173    unsigned NoReturn : 1;
174
175    /// Whether this function is returns-retained.
176    unsigned ReturnsRetained : 1;
177
178    /// How many arguments to pass inreg.
179    unsigned HasRegParm : 1;
180    unsigned RegParm : 4;
181
182    RequiredArgs Required;
183
184    unsigned NumArgs;
185    ArgInfo *getArgsBuffer() {
186      return reinterpret_cast<ArgInfo*>(this+1);
187    }
188    const ArgInfo *getArgsBuffer() const {
189      return reinterpret_cast<const ArgInfo*>(this + 1);
190    }
191
192    CGFunctionInfo() : Required(RequiredArgs::All) {}
193
194  public:
195    static CGFunctionInfo *create(unsigned llvmCC,
196                                  const FunctionType::ExtInfo &extInfo,
197                                  CanQualType resultType,
198                                  ArrayRef<CanQualType> argTypes,
199                                  RequiredArgs required);
200
201    typedef const ArgInfo *const_arg_iterator;
202    typedef ArgInfo *arg_iterator;
203
204    const_arg_iterator arg_begin() const { return getArgsBuffer() + 1; }
205    const_arg_iterator arg_end() const { return getArgsBuffer() + 1 + NumArgs; }
206    arg_iterator arg_begin() { return getArgsBuffer() + 1; }
207    arg_iterator arg_end() { return getArgsBuffer() + 1 + NumArgs; }
208
209    unsigned  arg_size() const { return NumArgs; }
210
211    bool isVariadic() const { return Required.allowsOptionalArgs(); }
212    RequiredArgs getRequiredArgs() const { return Required; }
213
214    bool isNoReturn() const { return NoReturn; }
215
216    /// In ARC, whether this function retains its return value.  This
217    /// is not always reliable for call sites.
218    bool isReturnsRetained() const { return ReturnsRetained; }
219
220    /// getASTCallingConvention() - Return the AST-specified calling
221    /// convention.
222    CallingConv getASTCallingConvention() const {
223      return CallingConv(ASTCallingConvention);
224    }
225
226    /// getCallingConvention - Return the user specified calling
227    /// convention, which has been translated into an LLVM CC.
228    unsigned getCallingConvention() const { return CallingConvention; }
229
230    /// getEffectiveCallingConvention - Return the actual calling convention to
231    /// use, which may depend on the ABI.
232    unsigned getEffectiveCallingConvention() const {
233      return EffectiveCallingConvention;
234    }
235    void setEffectiveCallingConvention(unsigned Value) {
236      EffectiveCallingConvention = Value;
237    }
238
239    bool getHasRegParm() const { return HasRegParm; }
240    unsigned getRegParm() const { return RegParm; }
241
242    FunctionType::ExtInfo getExtInfo() const {
243      return FunctionType::ExtInfo(isNoReturn(),
244                                   getHasRegParm(), getRegParm(),
245                                   getASTCallingConvention(),
246                                   isReturnsRetained());
247    }
248
249    CanQualType getReturnType() const { return getArgsBuffer()[0].type; }
250
251    ABIArgInfo &getReturnInfo() { return getArgsBuffer()[0].info; }
252    const ABIArgInfo &getReturnInfo() const { return getArgsBuffer()[0].info; }
253
254    void Profile(llvm::FoldingSetNodeID &ID) {
255      ID.AddInteger(getASTCallingConvention());
256      ID.AddBoolean(NoReturn);
257      ID.AddBoolean(ReturnsRetained);
258      ID.AddBoolean(HasRegParm);
259      ID.AddInteger(RegParm);
260      ID.AddInteger(Required.getOpaqueData());
261      getReturnType().Profile(ID);
262      for (arg_iterator it = arg_begin(), ie = arg_end(); it != ie; ++it)
263        it->type.Profile(ID);
264    }
265    static void Profile(llvm::FoldingSetNodeID &ID,
266                        const FunctionType::ExtInfo &info,
267                        RequiredArgs required,
268                        CanQualType resultType,
269                        ArrayRef<CanQualType> argTypes) {
270      ID.AddInteger(info.getCC());
271      ID.AddBoolean(info.getNoReturn());
272      ID.AddBoolean(info.getProducesResult());
273      ID.AddBoolean(info.getHasRegParm());
274      ID.AddInteger(info.getRegParm());
275      ID.AddInteger(required.getOpaqueData());
276      resultType.Profile(ID);
277      for (ArrayRef<CanQualType>::iterator
278             i = argTypes.begin(), e = argTypes.end(); i != e; ++i) {
279        i->Profile(ID);
280      }
281    }
282  };
283
284  /// ReturnValueSlot - Contains the address where the return value of a
285  /// function can be stored, and whether the address is volatile or not.
286  class ReturnValueSlot {
287    llvm::PointerIntPair<llvm::Value *, 1, bool> Value;
288
289  public:
290    ReturnValueSlot() {}
291    ReturnValueSlot(llvm::Value *Value, bool IsVolatile)
292      : Value(Value, IsVolatile) {}
293
294    bool isNull() const { return !getValue(); }
295
296    bool isVolatile() const { return Value.getInt(); }
297    llvm::Value *getValue() const { return Value.getPointer(); }
298  };
299
300}  // end namespace CodeGen
301}  // end namespace clang
302
303#endif
304