1 //===-- llvm/Function.h - Class to represent a single function --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file contains the declaration of the Function class, which represents a
11 // single function/procedure in LLVM.
13 // A function basically consists of a list of basic blocks, a list of arguments,
14 // and a symbol table.
16 //===----------------------------------------------------------------------===//
18 #ifndef LLVM_FUNCTION_H
19 #define LLVM_FUNCTION_H
21 #include "llvm/Argument.h"
22 #include "llvm/Attributes.h"
23 #include "llvm/BasicBlock.h"
24 #include "llvm/CallingConv.h"
25 #include "llvm/GlobalValue.h"
26 #include "llvm/Support/Compiler.h"
33 // Traits for intrusive list of basic blocks...
34 template<> struct ilist_traits<BasicBlock>
35 : public SymbolTableListTraits<BasicBlock, Function> {
37 // createSentinel is used to get hold of the node that marks the end of the
38 // list... (same trick used here as in ilist_traits<Instruction>)
39 BasicBlock *createSentinel() const {
40 return static_cast<BasicBlock*>(&Sentinel);
42 static void destroySentinel(BasicBlock*) {}
44 BasicBlock *provideInitialHead() const { return createSentinel(); }
45 BasicBlock *ensureHead(BasicBlock*) const { return createSentinel(); }
46 static void noteHead(BasicBlock*, BasicBlock*) {}
48 static ValueSymbolTable *getSymTab(Function *ItemParent);
50 mutable ilist_half_node<BasicBlock> Sentinel;
53 template<> struct ilist_traits<Argument>
54 : public SymbolTableListTraits<Argument, Function> {
56 Argument *createSentinel() const {
57 return static_cast<Argument*>(&Sentinel);
59 static void destroySentinel(Argument*) {}
61 Argument *provideInitialHead() const { return createSentinel(); }
62 Argument *ensureHead(Argument*) const { return createSentinel(); }
63 static void noteHead(Argument*, Argument*) {}
65 static ValueSymbolTable *getSymTab(Function *ItemParent);
67 mutable ilist_half_node<Argument> Sentinel;
70 class Function : public GlobalValue,
71 public ilist_node<Function> {
73 typedef iplist<Argument> ArgumentListType;
74 typedef iplist<BasicBlock> BasicBlockListType;
76 // BasicBlock iterators...
77 typedef BasicBlockListType::iterator iterator;
78 typedef BasicBlockListType::const_iterator const_iterator;
80 typedef ArgumentListType::iterator arg_iterator;
81 typedef ArgumentListType::const_iterator const_arg_iterator;
84 // Important things that make up a function!
85 BasicBlockListType BasicBlocks; ///< The basic blocks
86 mutable ArgumentListType ArgumentList; ///< The formal arguments
87 ValueSymbolTable *SymTab; ///< Symbol table of args/instructions
88 AttributeSet AttributeList; ///< Parameter attributes
90 // HasLazyArguments is stored in Value::SubclassData.
91 /*bool HasLazyArguments;*/
93 // The Calling Convention is stored in Value::SubclassData.
94 /*CallingConv::ID CallingConvention;*/
96 friend class SymbolTableListTraits<Function, Module>;
98 void setParent(Module *parent);
100 /// hasLazyArguments/CheckLazyArguments - The argument list of a function is
101 /// built on demand, so that the list isn't allocated until the first client
102 /// needs it. The hasLazyArguments predicate returns true if the arg list
103 /// hasn't been set up yet.
104 bool hasLazyArguments() const {
105 return getSubclassDataFromValue() & 1;
107 void CheckLazyArguments() const {
108 if (hasLazyArguments())
109 BuildLazyArguments();
111 void BuildLazyArguments() const;
113 Function(const Function&) LLVM_DELETED_FUNCTION;
114 void operator=(const Function&) LLVM_DELETED_FUNCTION;
116 /// Function ctor - If the (optional) Module argument is specified, the
117 /// function is automatically inserted into the end of the function list for
120 Function(FunctionType *Ty, LinkageTypes Linkage,
121 const Twine &N = "", Module *M = 0);
124 static Function *Create(FunctionType *Ty, LinkageTypes Linkage,
125 const Twine &N = "", Module *M = 0) {
126 return new(0) Function(Ty, Linkage, N, M);
131 Type *getReturnType() const; // Return the type of the ret val
132 FunctionType *getFunctionType() const; // Return the FunctionType for me
134 /// getContext - Return a pointer to the LLVMContext associated with this
135 /// function, or NULL if this function is not bound to a context yet.
136 LLVMContext &getContext() const;
138 /// isVarArg - Return true if this function takes a variable number of
140 bool isVarArg() const;
142 /// getIntrinsicID - This method returns the ID number of the specified
143 /// function, or Intrinsic::not_intrinsic if the function is not an
144 /// instrinsic, or if the pointer is null. This value is always defined to be
145 /// zero to allow easy checking for whether a function is intrinsic or not.
146 /// The particular intrinsic functions which correspond to this value are
147 /// defined in llvm/Intrinsics.h.
149 unsigned getIntrinsicID() const LLVM_READONLY;
150 bool isIntrinsic() const { return getName().startswith("llvm."); }
152 /// getCallingConv()/setCallingConv(CC) - These method get and set the
153 /// calling convention of this function. The enum values for the known
154 /// calling conventions are defined in CallingConv.h.
155 CallingConv::ID getCallingConv() const {
156 return static_cast<CallingConv::ID>(getSubclassDataFromValue() >> 1);
158 void setCallingConv(CallingConv::ID CC) {
159 setValueSubclassData((getSubclassDataFromValue() & 1) |
160 (static_cast<unsigned>(CC) << 1));
163 /// getAttributes - Return the attribute list for this Function.
165 const AttributeSet &getAttributes() const { return AttributeList; }
167 /// setAttributes - Set the attribute list for this Function.
169 void setAttributes(const AttributeSet &attrs) { AttributeList = attrs; }
171 /// getFnAttributes - Return the function attributes for querying.
173 Attribute getFnAttributes() const {
174 return AttributeList.getFnAttributes();
177 /// addFnAttr - Add function attributes to this function.
179 void addFnAttr(Attribute::AttrKind N) {
180 // Function Attribute are stored at ~0 index
181 addAttribute(AttributeSet::FunctionIndex, Attribute::get(getContext(), N));
184 /// removeFnAttr - Remove function attributes from this function.
186 void removeFnAttr(Attribute N) {
187 // Function Attribute are stored at ~0 index
188 removeAttribute(~0U, N);
191 /// hasGC/getGC/setGC/clearGC - The name of the garbage collection algorithm
192 /// to use during code generation.
194 const char *getGC() const;
195 void setGC(const char *Str);
199 /// getRetAttributes - Return the return attributes for querying.
200 Attribute getRetAttributes() const {
201 return AttributeList.getRetAttributes();
204 /// getParamAttributes - Return the parameter attributes for querying.
205 Attribute getParamAttributes(unsigned Idx) const {
206 return AttributeList.getParamAttributes(Idx);
209 /// addAttribute - adds the attribute to the list of attributes.
210 void addAttribute(unsigned i, Attribute attr);
212 /// removeAttribute - removes the attribute from the list of attributes.
213 void removeAttribute(unsigned i, Attribute attr);
215 /// @brief Extract the alignment for a call or parameter (0=unknown).
216 unsigned getParamAlignment(unsigned i) const {
217 return AttributeList.getParamAlignment(i);
220 /// @brief Determine if the function does not access memory.
221 bool doesNotAccessMemory() const {
222 return getFnAttributes().hasAttribute(Attribute::ReadNone);
224 void setDoesNotAccessMemory() {
225 addFnAttr(Attribute::ReadNone);
228 /// @brief Determine if the function does not access or only reads memory.
229 bool onlyReadsMemory() const {
230 return doesNotAccessMemory() ||
231 getFnAttributes().hasAttribute(Attribute::ReadOnly);
233 void setOnlyReadsMemory() {
234 addFnAttr(Attribute::ReadOnly);
237 /// @brief Determine if the function cannot return.
238 bool doesNotReturn() const {
239 return getFnAttributes().hasAttribute(Attribute::NoReturn);
241 void setDoesNotReturn() {
242 addFnAttr(Attribute::NoReturn);
245 /// @brief Determine if the function cannot unwind.
246 bool doesNotThrow() const {
247 return getFnAttributes().hasAttribute(Attribute::NoUnwind);
249 void setDoesNotThrow() {
250 addFnAttr(Attribute::NoUnwind);
253 /// @brief Determine if the call cannot be duplicated.
254 bool cannotDuplicate() const {
255 return getFnAttributes().hasAttribute(Attribute::NoDuplicate);
257 void setCannotDuplicate() {
258 addFnAttr(Attribute::NoDuplicate);
261 /// @brief True if the ABI mandates (or the user requested) that this
262 /// function be in a unwind table.
263 bool hasUWTable() const {
264 return getFnAttributes().hasAttribute(Attribute::UWTable);
266 void setHasUWTable() {
267 addFnAttr(Attribute::UWTable);
270 /// @brief True if this function needs an unwind table.
271 bool needsUnwindTableEntry() const {
272 return hasUWTable() || !doesNotThrow();
275 /// @brief Determine if the function returns a structure through first
276 /// pointer argument.
277 bool hasStructRetAttr() const {
278 return getParamAttributes(1).hasAttribute(Attribute::StructRet);
281 /// @brief Determine if the parameter does not alias other parameters.
282 /// @param n The parameter to check. 1 is the first parameter, 0 is the return
283 bool doesNotAlias(unsigned n) const {
284 return getParamAttributes(n).hasAttribute(Attribute::NoAlias);
286 void setDoesNotAlias(unsigned n) {
287 addAttribute(n, Attribute::get(getContext(), Attribute::NoAlias));
290 /// @brief Determine if the parameter can be captured.
291 /// @param n The parameter to check. 1 is the first parameter, 0 is the return
292 bool doesNotCapture(unsigned n) const {
293 return getParamAttributes(n).hasAttribute(Attribute::NoCapture);
295 void setDoesNotCapture(unsigned n) {
296 addAttribute(n, Attribute::get(getContext(), Attribute::NoCapture));
299 /// copyAttributesFrom - copy all additional attributes (those not needed to
300 /// create a Function) from the Function Src to this one.
301 void copyAttributesFrom(const GlobalValue *Src);
303 /// deleteBody - This method deletes the body of the function, and converts
304 /// the linkage to external.
308 setLinkage(ExternalLinkage);
311 /// removeFromParent - This method unlinks 'this' from the containing module,
312 /// but does not delete it.
314 virtual void removeFromParent();
316 /// eraseFromParent - This method unlinks 'this' from the containing module
319 virtual void eraseFromParent();
322 /// Get the underlying elements of the Function... the basic block list is
323 /// empty for external functions.
325 const ArgumentListType &getArgumentList() const {
326 CheckLazyArguments();
329 ArgumentListType &getArgumentList() {
330 CheckLazyArguments();
333 static iplist<Argument> Function::*getSublistAccess(Argument*) {
334 return &Function::ArgumentList;
337 const BasicBlockListType &getBasicBlockList() const { return BasicBlocks; }
338 BasicBlockListType &getBasicBlockList() { return BasicBlocks; }
339 static iplist<BasicBlock> Function::*getSublistAccess(BasicBlock*) {
340 return &Function::BasicBlocks;
343 const BasicBlock &getEntryBlock() const { return front(); }
344 BasicBlock &getEntryBlock() { return front(); }
346 //===--------------------------------------------------------------------===//
347 // Symbol Table Accessing functions...
349 /// getSymbolTable() - Return the symbol table...
351 inline ValueSymbolTable &getValueSymbolTable() { return *SymTab; }
352 inline const ValueSymbolTable &getValueSymbolTable() const { return *SymTab; }
355 //===--------------------------------------------------------------------===//
356 // BasicBlock iterator forwarding functions
358 iterator begin() { return BasicBlocks.begin(); }
359 const_iterator begin() const { return BasicBlocks.begin(); }
360 iterator end () { return BasicBlocks.end(); }
361 const_iterator end () const { return BasicBlocks.end(); }
363 size_t size() const { return BasicBlocks.size(); }
364 bool empty() const { return BasicBlocks.empty(); }
365 const BasicBlock &front() const { return BasicBlocks.front(); }
366 BasicBlock &front() { return BasicBlocks.front(); }
367 const BasicBlock &back() const { return BasicBlocks.back(); }
368 BasicBlock &back() { return BasicBlocks.back(); }
370 //===--------------------------------------------------------------------===//
371 // Argument iterator forwarding functions
373 arg_iterator arg_begin() {
374 CheckLazyArguments();
375 return ArgumentList.begin();
377 const_arg_iterator arg_begin() const {
378 CheckLazyArguments();
379 return ArgumentList.begin();
381 arg_iterator arg_end() {
382 CheckLazyArguments();
383 return ArgumentList.end();
385 const_arg_iterator arg_end() const {
386 CheckLazyArguments();
387 return ArgumentList.end();
390 size_t arg_size() const;
391 bool arg_empty() const;
393 /// viewCFG - This function is meant for use from the debugger. You can just
394 /// say 'call F->viewCFG()' and a ghostview window should pop up from the
395 /// program, displaying the CFG of the current function with the code for each
396 /// basic block inside. This depends on there being a 'dot' and 'gv' program
399 void viewCFG() const;
401 /// viewCFGOnly - This function is meant for use from the debugger. It works
402 /// just like viewCFG, but it does not include the contents of basic blocks
403 /// into the nodes, just the label. If you are only interested in the CFG
404 /// this can make the graph smaller.
406 void viewCFGOnly() const;
408 /// Methods for support type inquiry through isa, cast, and dyn_cast:
409 static inline bool classof(const Value *V) {
410 return V->getValueID() == Value::FunctionVal;
413 /// dropAllReferences() - This method causes all the subinstructions to "let
414 /// go" of all references that they are maintaining. This allows one to
415 /// 'delete' a whole module at a time, even though there may be circular
416 /// references... first all references are dropped, and all use counts go to
417 /// zero. Then everything is deleted for real. Note that no operations are
418 /// valid on an object that has "dropped all references", except operator
421 /// Since no other object in the module can have references into the body of a
422 /// function, dropping all references deletes the entire body of the function,
423 /// including any contained basic blocks.
425 void dropAllReferences();
427 /// hasAddressTaken - returns true if there are any uses of this function
428 /// other than direct calls or invokes to it, or blockaddress expressions.
429 /// Optionally passes back an offending user for diagnostic purposes.
431 bool hasAddressTaken(const User** = 0) const;
433 /// isDefTriviallyDead - Return true if it is trivially safe to remove
434 /// this function definition from the module (because it isn't externally
435 /// visible, does not have its address taken, and has no callers). To make
436 /// this more accurate, call removeDeadConstantUsers first.
437 bool isDefTriviallyDead() const;
439 /// callsFunctionThatReturnsTwice - Return true if the function has a call to
440 /// setjmp or other function that gcc recognizes as "returning twice".
441 bool callsFunctionThatReturnsTwice() const;
444 // Shadow Value::setValueSubclassData with a private forwarding method so that
445 // subclasses cannot accidentally use it.
446 void setValueSubclassData(unsigned short D) {
447 Value::setValueSubclassData(D);
451 inline ValueSymbolTable *
452 ilist_traits<BasicBlock>::getSymTab(Function *F) {
453 return F ? &F->getValueSymbolTable() : 0;
456 inline ValueSymbolTable *
457 ilist_traits<Argument>::getSymTab(Function *F) {
458 return F ? &F->getValueSymbolTable() : 0;
461 } // End llvm namespace