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 "llvm/ADT/FoldingSet.h"
19#include "llvm/Value.h"
20#include "clang/AST/Type.h"
21#include "clang/AST/CanonicalType.h"
22
23#include "CGValue.h"
24
25// FIXME: Restructure so we don't have to expose so much stuff.
26#include "ABIInfo.h"
27
28namespace llvm {
29  struct AttributeWithIndex;
30  class Function;
31  class Type;
32  class Value;
33
34  template<typename T, unsigned> class SmallVector;
35}
36
37namespace clang {
38  class ASTContext;
39  class Decl;
40  class FunctionDecl;
41  class ObjCMethodDecl;
42  class VarDecl;
43
44namespace CodeGen {
45  typedef SmallVector<llvm::AttributeWithIndex, 8> AttributeListType;
46
47  struct CallArg {
48    RValue RV;
49    QualType Ty;
50    bool NeedsCopy;
51    CallArg(RValue rv, QualType ty, bool needscopy)
52    : RV(rv), Ty(ty), NeedsCopy(needscopy)
53    { }
54  };
55
56  /// CallArgList - Type for representing both the value and type of
57  /// arguments in a call.
58  class CallArgList :
59    public SmallVector<CallArg, 16> {
60  public:
61    struct Writeback {
62      /// The original argument.
63      llvm::Value *Address;
64
65      /// The pointee type of the original argument.
66      QualType AddressType;
67
68      /// The temporary alloca.
69      llvm::Value *Temporary;
70    };
71
72    void add(RValue rvalue, QualType type, bool needscopy = false) {
73      push_back(CallArg(rvalue, type, needscopy));
74    }
75
76    void addFrom(const CallArgList &other) {
77      insert(end(), other.begin(), other.end());
78      Writebacks.insert(Writebacks.end(),
79                        other.Writebacks.begin(), other.Writebacks.end());
80    }
81
82    void addWriteback(llvm::Value *address, QualType addressType,
83                      llvm::Value *temporary) {
84      Writeback writeback;
85      writeback.Address = address;
86      writeback.AddressType = addressType;
87      writeback.Temporary = temporary;
88      Writebacks.push_back(writeback);
89    }
90
91    bool hasWritebacks() const { return !Writebacks.empty(); }
92
93    typedef SmallVectorImpl<Writeback>::const_iterator writeback_iterator;
94    writeback_iterator writeback_begin() const { return Writebacks.begin(); }
95    writeback_iterator writeback_end() const { return Writebacks.end(); }
96
97  private:
98    SmallVector<Writeback, 1> Writebacks;
99  };
100
101  /// A class for recording the number of arguments that a function
102  /// signature requires.
103  class RequiredArgs {
104    /// The number of required arguments, or ~0 if the signature does
105    /// not permit optional arguments.
106    unsigned NumRequired;
107  public:
108    enum All_t { All };
109
110    RequiredArgs(All_t _) : NumRequired(~0U) {}
111    explicit RequiredArgs(unsigned n) : NumRequired(n) {
112      assert(n != ~0U);
113    }
114
115    /// Compute the arguments required by the given formal prototype,
116    /// given that there may be some additional, non-formal arguments
117    /// in play.
118    static RequiredArgs forPrototypePlus(const FunctionProtoType *prototype,
119                                         unsigned additional) {
120      if (!prototype->isVariadic()) return All;
121      return RequiredArgs(prototype->getNumArgs() + additional);
122    }
123
124    static RequiredArgs forPrototype(const FunctionProtoType *prototype) {
125      return forPrototypePlus(prototype, 0);
126    }
127
128    static RequiredArgs forPrototype(CanQual<FunctionProtoType> prototype) {
129      return forPrototype(prototype.getTypePtr());
130    }
131
132    static RequiredArgs forPrototypePlus(CanQual<FunctionProtoType> prototype,
133                                         unsigned additional) {
134      return forPrototypePlus(prototype.getTypePtr(), additional);
135    }
136
137    bool allowsOptionalArgs() const { return NumRequired != ~0U; }
138    bool getNumRequiredArgs() const {
139      assert(allowsOptionalArgs());
140      return NumRequired;
141    }
142
143    unsigned getOpaqueData() const { return NumRequired; }
144    static RequiredArgs getFromOpaqueData(unsigned value) {
145      if (value == ~0U) return All;
146      return RequiredArgs(value);
147    }
148  };
149
150  /// FunctionArgList - Type for representing both the decl and type
151  /// of parameters to a function. The decl must be either a
152  /// ParmVarDecl or ImplicitParamDecl.
153  class FunctionArgList : public SmallVector<const VarDecl*, 16> {
154  };
155
156  /// CGFunctionInfo - Class to encapsulate the information about a
157  /// function definition.
158  class CGFunctionInfo : public llvm::FoldingSetNode {
159    struct ArgInfo {
160      CanQualType type;
161      ABIArgInfo info;
162    };
163
164    /// The LLVM::CallingConv to use for this function (as specified by the
165    /// user).
166    unsigned CallingConvention : 8;
167
168    /// The LLVM::CallingConv to actually use for this function, which may
169    /// depend on the ABI.
170    unsigned EffectiveCallingConvention : 8;
171
172    /// The clang::CallingConv that this was originally created with.
173    unsigned ASTCallingConvention : 8;
174
175    /// Whether this function is noreturn.
176    unsigned NoReturn : 1;
177
178    /// Whether this function is returns-retained.
179    unsigned ReturnsRetained : 1;
180
181    /// How many arguments to pass inreg.
182    unsigned HasRegParm : 1;
183    unsigned RegParm : 4;
184
185    RequiredArgs Required;
186
187    unsigned NumArgs;
188    ArgInfo *getArgsBuffer() {
189      return reinterpret_cast<ArgInfo*>(this+1);
190    }
191    const ArgInfo *getArgsBuffer() const {
192      return reinterpret_cast<const ArgInfo*>(this + 1);
193    }
194
195    CGFunctionInfo() : Required(RequiredArgs::All) {}
196
197  public:
198    static CGFunctionInfo *create(unsigned llvmCC,
199                                  const FunctionType::ExtInfo &extInfo,
200                                  CanQualType resultType,
201                                  ArrayRef<CanQualType> argTypes,
202                                  RequiredArgs required);
203
204    typedef const ArgInfo *const_arg_iterator;
205    typedef ArgInfo *arg_iterator;
206
207    const_arg_iterator arg_begin() const { return getArgsBuffer() + 1; }
208    const_arg_iterator arg_end() const { return getArgsBuffer() + 1 + NumArgs; }
209    arg_iterator arg_begin() { return getArgsBuffer() + 1; }
210    arg_iterator arg_end() { return getArgsBuffer() + 1 + NumArgs; }
211
212    unsigned  arg_size() const { return NumArgs; }
213
214    bool isVariadic() const { return Required.allowsOptionalArgs(); }
215    RequiredArgs getRequiredArgs() const { return Required; }
216
217    bool isNoReturn() const { return NoReturn; }
218
219    /// In ARC, whether this function retains its return value.  This
220    /// is not always reliable for call sites.
221    bool isReturnsRetained() const { return ReturnsRetained; }
222
223    /// getASTCallingConvention() - Return the AST-specified calling
224    /// convention.
225    CallingConv getASTCallingConvention() const {
226      return CallingConv(ASTCallingConvention);
227    }
228
229    /// getCallingConvention - Return the user specified calling
230    /// convention, which has been translated into an LLVM CC.
231    unsigned getCallingConvention() const { return CallingConvention; }
232
233    /// getEffectiveCallingConvention - Return the actual calling convention to
234    /// use, which may depend on the ABI.
235    unsigned getEffectiveCallingConvention() const {
236      return EffectiveCallingConvention;
237    }
238    void setEffectiveCallingConvention(unsigned Value) {
239      EffectiveCallingConvention = Value;
240    }
241
242    bool getHasRegParm() const { return HasRegParm; }
243    unsigned getRegParm() const { return RegParm; }
244
245    FunctionType::ExtInfo getExtInfo() const {
246      return FunctionType::ExtInfo(isNoReturn(),
247                                   getHasRegParm(), getRegParm(),
248                                   getASTCallingConvention(),
249                                   isReturnsRetained());
250    }
251
252    CanQualType getReturnType() const { return getArgsBuffer()[0].type; }
253
254    ABIArgInfo &getReturnInfo() { return getArgsBuffer()[0].info; }
255    const ABIArgInfo &getReturnInfo() const { return getArgsBuffer()[0].info; }
256
257    void Profile(llvm::FoldingSetNodeID &ID) {
258      ID.AddInteger(getASTCallingConvention());
259      ID.AddBoolean(NoReturn);
260      ID.AddBoolean(ReturnsRetained);
261      ID.AddBoolean(HasRegParm);
262      ID.AddInteger(RegParm);
263      ID.AddInteger(Required.getOpaqueData());
264      getReturnType().Profile(ID);
265      for (arg_iterator it = arg_begin(), ie = arg_end(); it != ie; ++it)
266        it->type.Profile(ID);
267    }
268    static void Profile(llvm::FoldingSetNodeID &ID,
269                        const FunctionType::ExtInfo &info,
270                        RequiredArgs required,
271                        CanQualType resultType,
272                        ArrayRef<CanQualType> argTypes) {
273      ID.AddInteger(info.getCC());
274      ID.AddBoolean(info.getNoReturn());
275      ID.AddBoolean(info.getProducesResult());
276      ID.AddBoolean(info.getHasRegParm());
277      ID.AddInteger(info.getRegParm());
278      ID.AddInteger(required.getOpaqueData());
279      resultType.Profile(ID);
280      for (ArrayRef<CanQualType>::iterator
281             i = argTypes.begin(), e = argTypes.end(); i != e; ++i) {
282        i->Profile(ID);
283      }
284    }
285  };
286
287  /// ReturnValueSlot - Contains the address where the return value of a
288  /// function can be stored, and whether the address is volatile or not.
289  class ReturnValueSlot {
290    llvm::PointerIntPair<llvm::Value *, 1, bool> Value;
291
292  public:
293    ReturnValueSlot() {}
294    ReturnValueSlot(llvm::Value *Value, bool IsVolatile)
295      : Value(Value, IsVolatile) {}
296
297    bool isNull() const { return !getValue(); }
298
299    bool isVolatile() const { return Value.getInt(); }
300    llvm::Value *getValue() const { return Value.getPointer(); }
301  };
302
303}  // end namespace CodeGen
304}  // end namespace clang
305
306#endif
307