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1 //===-- llvm/Support/CallSite.h - Abstract Call & Invoke instrs -*- 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 // This file defines the CallSite class, which is a handy wrapper for code that
11 // wants to treat Call and Invoke instructions in a generic way. When in non-
12 // mutation context (e.g. an analysis) ImmutableCallSite should be used.
13 // Finally, when some degree of customization is necessary between these two
14 // extremes, CallSiteBase<> can be supplied with fine-tuned parameters.
15 //
16 // NOTE: These classes are supposed to have "value semantics". So they should be
17 // passed by value, not by reference; they should not be "new"ed or "delete"d.
18 // They are efficiently copyable, assignable and constructable, with cost
19 // equivalent to copying a pointer (notice that they have only a single data
20 // member). The internal representation carries a flag which indicates which of
21 // the two variants is enclosed. This allows for cheaper checks when various
22 // accessors of CallSite are employed.
23 //
24 //===----------------------------------------------------------------------===//
25 
26 #ifndef LLVM_SUPPORT_CALLSITE_H
27 #define LLVM_SUPPORT_CALLSITE_H
28 
29 #include "llvm/Attributes.h"
30 #include "llvm/ADT/PointerIntPair.h"
31 #include "llvm/BasicBlock.h"
32 #include "llvm/CallingConv.h"
33 #include "llvm/Instructions.h"
34 
35 namespace llvm {
36 
37 class CallInst;
38 class InvokeInst;
39 
40 template <typename FunTy = const Function,
41           typename ValTy = const Value,
42           typename UserTy = const User,
43           typename InstrTy = const Instruction,
44           typename CallTy = const CallInst,
45           typename InvokeTy = const InvokeInst,
46           typename IterTy = User::const_op_iterator>
47 class CallSiteBase {
48 protected:
49   PointerIntPair<InstrTy*, 1, bool> I;
50 public:
CallSiteBase()51   CallSiteBase() : I(0, false) {}
CallSiteBase(CallTy * CI)52   CallSiteBase(CallTy *CI) : I(CI, true) { assert(CI); }
CallSiteBase(InvokeTy * II)53   CallSiteBase(InvokeTy *II) : I(II, false) { assert(II); }
CallSiteBase(ValTy * II)54   CallSiteBase(ValTy *II) { *this = get(II); }
55 protected:
56   /// CallSiteBase::get - This static method is sort of like a constructor.  It
57   /// will create an appropriate call site for a Call or Invoke instruction, but
58   /// it can also create a null initialized CallSiteBase object for something
59   /// which is NOT a call site.
60   ///
get(ValTy * V)61   static CallSiteBase get(ValTy *V) {
62     if (InstrTy *II = dyn_cast<InstrTy>(V)) {
63       if (II->getOpcode() == Instruction::Call)
64         return CallSiteBase(static_cast<CallTy*>(II));
65       else if (II->getOpcode() == Instruction::Invoke)
66         return CallSiteBase(static_cast<InvokeTy*>(II));
67     }
68     return CallSiteBase();
69   }
70 public:
71   /// isCall - true if a CallInst is enclosed.
72   /// Note that !isCall() does not mean it is an InvokeInst enclosed,
73   /// it also could signify a NULL Instruction pointer.
isCall()74   bool isCall() const { return I.getInt(); }
75 
76   /// isInvoke - true if a InvokeInst is enclosed.
77   ///
isInvoke()78   bool isInvoke() const { return getInstruction() && !I.getInt(); }
79 
getInstruction()80   InstrTy *getInstruction() const { return I.getPointer(); }
81   InstrTy *operator->() const { return I.getPointer(); }
82   operator bool() const { return I.getPointer(); }
83 
84   /// getCalledValue - Return the pointer to function that is being called...
85   ///
getCalledValue()86   ValTy *getCalledValue() const {
87     assert(getInstruction() && "Not a call or invoke instruction!");
88     return *getCallee();
89   }
90 
91   /// getCalledFunction - Return the function being called if this is a direct
92   /// call, otherwise return null (if it's an indirect call).
93   ///
getCalledFunction()94   FunTy *getCalledFunction() const {
95     return dyn_cast<FunTy>(getCalledValue());
96   }
97 
98   /// setCalledFunction - Set the callee to the specified value...
99   ///
setCalledFunction(Value * V)100   void setCalledFunction(Value *V) {
101     assert(getInstruction() && "Not a call or invoke instruction!");
102     *getCallee() = V;
103   }
104 
105   /// isCallee - Determine whether the passed iterator points to the
106   /// callee operand's Use.
107   ///
isCallee(value_use_iterator<UserTy> UI)108   bool isCallee(value_use_iterator<UserTy> UI) const {
109     return getCallee() == &UI.getUse();
110   }
111 
getArgument(unsigned ArgNo)112   ValTy *getArgument(unsigned ArgNo) const {
113     assert(arg_begin() + ArgNo < arg_end() && "Argument # out of range!");
114     return *(arg_begin() + ArgNo);
115   }
116 
setArgument(unsigned ArgNo,Value * newVal)117   void setArgument(unsigned ArgNo, Value* newVal) {
118     assert(getInstruction() && "Not a call or invoke instruction!");
119     assert(arg_begin() + ArgNo < arg_end() && "Argument # out of range!");
120     getInstruction()->setOperand(ArgNo, newVal);
121   }
122 
123   /// Given a value use iterator, returns the argument that corresponds to it.
124   /// Iterator must actually correspond to an argument.
getArgumentNo(value_use_iterator<UserTy> I)125   unsigned getArgumentNo(value_use_iterator<UserTy> I) const {
126     assert(getInstruction() && "Not a call or invoke instruction!");
127     assert(arg_begin() <= &I.getUse() && &I.getUse() < arg_end()
128            && "Argument # out of range!");
129     return &I.getUse() - arg_begin();
130   }
131 
132   /// arg_iterator - The type of iterator to use when looping over actual
133   /// arguments at this call site...
134   typedef IterTy arg_iterator;
135 
136   /// arg_begin/arg_end - Return iterators corresponding to the actual argument
137   /// list for a call site.
arg_begin()138   IterTy arg_begin() const {
139     assert(getInstruction() && "Not a call or invoke instruction!");
140     // Skip non-arguments
141     return (*this)->op_begin();
142   }
143 
arg_end()144   IterTy arg_end() const { return (*this)->op_end() - getArgumentEndOffset(); }
arg_empty()145   bool arg_empty() const { return arg_end() == arg_begin(); }
arg_size()146   unsigned arg_size() const { return unsigned(arg_end() - arg_begin()); }
147 
148   /// getType - Return the type of the instruction that generated this call site
149   ///
getType()150   Type *getType() const { return (*this)->getType(); }
151 
152   /// getCaller - Return the caller function for this call site
153   ///
getCaller()154   FunTy *getCaller() const { return (*this)->getParent()->getParent(); }
155 
156 #define CALLSITE_DELEGATE_GETTER(METHOD) \
157   InstrTy *II = getInstruction();    \
158   return isCall()                        \
159     ? cast<CallInst>(II)->METHOD         \
160     : cast<InvokeInst>(II)->METHOD
161 
162 #define CALLSITE_DELEGATE_SETTER(METHOD) \
163   InstrTy *II = getInstruction();    \
164   if (isCall())                          \
165     cast<CallInst>(II)->METHOD;          \
166   else                                   \
167     cast<InvokeInst>(II)->METHOD
168 
169   /// getCallingConv/setCallingConv - get or set the calling convention of the
170   /// call.
getCallingConv()171   CallingConv::ID getCallingConv() const {
172     CALLSITE_DELEGATE_GETTER(getCallingConv());
173   }
setCallingConv(CallingConv::ID CC)174   void setCallingConv(CallingConv::ID CC) {
175     CALLSITE_DELEGATE_SETTER(setCallingConv(CC));
176   }
177 
178   /// getAttributes/setAttributes - get or set the parameter attributes of
179   /// the call.
getAttributes()180   const AttrListPtr &getAttributes() const {
181     CALLSITE_DELEGATE_GETTER(getAttributes());
182   }
setAttributes(const AttrListPtr & PAL)183   void setAttributes(const AttrListPtr &PAL) {
184     CALLSITE_DELEGATE_SETTER(setAttributes(PAL));
185   }
186 
187   /// paramHasAttr - whether the call or the callee has the given attribute.
paramHasAttr(uint16_t i,Attributes attr)188   bool paramHasAttr(uint16_t i, Attributes attr) const {
189     CALLSITE_DELEGATE_GETTER(paramHasAttr(i, attr));
190   }
191 
192   /// @brief Extract the alignment for a call or parameter (0=unknown).
getParamAlignment(uint16_t i)193   uint16_t getParamAlignment(uint16_t i) const {
194     CALLSITE_DELEGATE_GETTER(getParamAlignment(i));
195   }
196 
197   /// @brief Return true if the call should not be inlined.
isNoInline()198   bool isNoInline() const {
199     CALLSITE_DELEGATE_GETTER(isNoInline());
200   }
201   void setIsNoInline(bool Value = true) {
202     CALLSITE_DELEGATE_SETTER(setIsNoInline(Value));
203   }
204 
205   /// @brief Determine if the call does not access memory.
doesNotAccessMemory()206   bool doesNotAccessMemory() const {
207     CALLSITE_DELEGATE_GETTER(doesNotAccessMemory());
208   }
209   void setDoesNotAccessMemory(bool doesNotAccessMemory = true) {
210     CALLSITE_DELEGATE_SETTER(setDoesNotAccessMemory(doesNotAccessMemory));
211   }
212 
213   /// @brief Determine if the call does not access or only reads memory.
onlyReadsMemory()214   bool onlyReadsMemory() const {
215     CALLSITE_DELEGATE_GETTER(onlyReadsMemory());
216   }
217   void setOnlyReadsMemory(bool onlyReadsMemory = true) {
218     CALLSITE_DELEGATE_SETTER(setOnlyReadsMemory(onlyReadsMemory));
219   }
220 
221   /// @brief Determine if the call cannot return.
doesNotReturn()222   bool doesNotReturn() const {
223     CALLSITE_DELEGATE_GETTER(doesNotReturn());
224   }
225   void setDoesNotReturn(bool doesNotReturn = true) {
226     CALLSITE_DELEGATE_SETTER(setDoesNotReturn(doesNotReturn));
227   }
228 
229   /// @brief Determine if the call cannot unwind.
doesNotThrow()230   bool doesNotThrow() const {
231     CALLSITE_DELEGATE_GETTER(doesNotThrow());
232   }
233   void setDoesNotThrow(bool doesNotThrow = true) {
234     CALLSITE_DELEGATE_SETTER(setDoesNotThrow(doesNotThrow));
235   }
236 
237 #undef CALLSITE_DELEGATE_GETTER
238 #undef CALLSITE_DELEGATE_SETTER
239 
240   /// hasArgument - Returns true if this CallSite passes the given Value* as an
241   /// argument to the called function.
hasArgument(const Value * Arg)242   bool hasArgument(const Value *Arg) const {
243     for (arg_iterator AI = this->arg_begin(), E = this->arg_end(); AI != E;
244          ++AI)
245       if (AI->get() == Arg)
246         return true;
247     return false;
248   }
249 
250 private:
getArgumentEndOffset()251   unsigned getArgumentEndOffset() const {
252     if (isCall())
253       return 1; // Skip Callee
254     else
255       return 3; // Skip BB, BB, Callee
256   }
257 
getCallee()258   IterTy getCallee() const {
259     if (isCall()) // Skip Callee
260       return cast<CallInst>(getInstruction())->op_end() - 1;
261     else // Skip BB, BB, Callee
262       return cast<InvokeInst>(getInstruction())->op_end() - 3;
263   }
264 };
265 
266 class CallSite : public CallSiteBase<Function, Value, User, Instruction,
267                                      CallInst, InvokeInst, User::op_iterator> {
268   typedef CallSiteBase<Function, Value, User, Instruction,
269                        CallInst, InvokeInst, User::op_iterator> Base;
270 public:
CallSite()271   CallSite() {}
CallSite(Base B)272   CallSite(Base B) : Base(B) {}
CallSite(Value * V)273   CallSite(Value* V) : Base(V) {}
CallSite(CallInst * CI)274   CallSite(CallInst *CI) : Base(CI) {}
CallSite(InvokeInst * II)275   CallSite(InvokeInst *II) : Base(II) {}
CallSite(Instruction * II)276   CallSite(Instruction *II) : Base(II) {}
277 
278   bool operator==(const CallSite &CS) const { return I == CS.I; }
279   bool operator!=(const CallSite &CS) const { return I != CS.I; }
280   bool operator<(const CallSite &CS) const {
281     return getInstruction() < CS.getInstruction();
282   }
283 
284 private:
285   User::op_iterator getCallee() const;
286 };
287 
288 /// ImmutableCallSite - establish a view to a call site for examination
289 class ImmutableCallSite : public CallSiteBase<> {
290   typedef CallSiteBase<> Base;
291 public:
ImmutableCallSite(const Value * V)292   ImmutableCallSite(const Value* V) : Base(V) {}
ImmutableCallSite(const CallInst * CI)293   ImmutableCallSite(const CallInst *CI) : Base(CI) {}
ImmutableCallSite(const InvokeInst * II)294   ImmutableCallSite(const InvokeInst *II) : Base(II) {}
ImmutableCallSite(const Instruction * II)295   ImmutableCallSite(const Instruction *II) : Base(II) {}
ImmutableCallSite(CallSite CS)296   ImmutableCallSite(CallSite CS) : Base(CS.getInstruction()) {}
297 };
298 
299 } // End llvm namespace
300 
301 #endif
302