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_IR_FUNCTION_H
19 #define LLVM_IR_FUNCTION_H
21 #include "llvm/IR/Argument.h"
22 #include "llvm/IR/Attributes.h"
23 #include "llvm/IR/BasicBlock.h"
24 #include "llvm/IR/CallingConv.h"
25 #include "llvm/IR/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 /// addFnAttr - Add function attributes to this function.
173 void addFnAttr(Attribute::AttrKind N) {
174 setAttributes(AttributeList.addAttribute(getContext(),
175 AttributeSet::FunctionIndex, N));
178 /// hasGC/getGC/setGC/clearGC - The name of the garbage collection algorithm
179 /// to use during code generation.
181 const char *getGC() const;
182 void setGC(const char *Str);
185 /// @brief adds the attribute to the list of attributes.
186 void addAttribute(unsigned i, Attribute::AttrKind attr);
188 /// @brief adds the attributes to the list of attributes.
189 void addAttributes(unsigned i, AttributeSet attrs);
191 /// @brief removes the attributes from the list of attributes.
192 void removeAttributes(unsigned i, AttributeSet attr);
194 /// @brief Extract the alignment for a call or parameter (0=unknown).
195 unsigned getParamAlignment(unsigned i) const {
196 return AttributeList.getParamAlignment(i);
199 /// @brief Determine if the function does not access memory.
200 bool doesNotAccessMemory() const {
201 return AttributeList.hasAttribute(AttributeSet::FunctionIndex,
202 Attribute::ReadNone);
204 void setDoesNotAccessMemory() {
205 addFnAttr(Attribute::ReadNone);
208 /// @brief Determine if the function does not access or only reads memory.
209 bool onlyReadsMemory() const {
210 return doesNotAccessMemory() ||
211 AttributeList.hasAttribute(AttributeSet::FunctionIndex,
212 Attribute::ReadOnly);
214 void setOnlyReadsMemory() {
215 addFnAttr(Attribute::ReadOnly);
218 /// @brief Determine if the function cannot return.
219 bool doesNotReturn() const {
220 return AttributeList.hasAttribute(AttributeSet::FunctionIndex,
221 Attribute::NoReturn);
223 void setDoesNotReturn() {
224 addFnAttr(Attribute::NoReturn);
227 /// @brief Determine if the function cannot unwind.
228 bool doesNotThrow() const {
229 return AttributeList.hasAttribute(AttributeSet::FunctionIndex,
230 Attribute::NoUnwind);
232 void setDoesNotThrow() {
233 addFnAttr(Attribute::NoUnwind);
236 /// @brief Determine if the call cannot be duplicated.
237 bool cannotDuplicate() const {
238 return AttributeList.hasAttribute(AttributeSet::FunctionIndex,
239 Attribute::NoDuplicate);
241 void setCannotDuplicate() {
242 addFnAttr(Attribute::NoDuplicate);
245 /// @brief True if the ABI mandates (or the user requested) that this
246 /// function be in a unwind table.
247 bool hasUWTable() const {
248 return AttributeList.hasAttribute(AttributeSet::FunctionIndex,
251 void setHasUWTable() {
252 addFnAttr(Attribute::UWTable);
255 /// @brief True if this function needs an unwind table.
256 bool needsUnwindTableEntry() const {
257 return hasUWTable() || !doesNotThrow();
260 /// @brief Determine if the function returns a structure through first
261 /// pointer argument.
262 bool hasStructRetAttr() const {
263 return AttributeList.hasAttribute(1, Attribute::StructRet);
266 /// @brief Determine if the parameter does not alias other parameters.
267 /// @param n The parameter to check. 1 is the first parameter, 0 is the return
268 bool doesNotAlias(unsigned n) const {
269 return AttributeList.hasAttribute(n, Attribute::NoAlias);
271 void setDoesNotAlias(unsigned n) {
272 addAttribute(n, Attribute::NoAlias);
275 /// @brief Determine if the parameter can be captured.
276 /// @param n The parameter to check. 1 is the first parameter, 0 is the return
277 bool doesNotCapture(unsigned n) const {
278 return AttributeList.hasAttribute(n, Attribute::NoCapture);
280 void setDoesNotCapture(unsigned n) {
281 addAttribute(n, Attribute::NoCapture);
284 /// copyAttributesFrom - copy all additional attributes (those not needed to
285 /// create a Function) from the Function Src to this one.
286 void copyAttributesFrom(const GlobalValue *Src);
288 /// deleteBody - This method deletes the body of the function, and converts
289 /// the linkage to external.
293 setLinkage(ExternalLinkage);
296 /// removeFromParent - This method unlinks 'this' from the containing module,
297 /// but does not delete it.
299 virtual void removeFromParent();
301 /// eraseFromParent - This method unlinks 'this' from the containing module
304 virtual void eraseFromParent();
307 /// Get the underlying elements of the Function... the basic block list is
308 /// empty for external functions.
310 const ArgumentListType &getArgumentList() const {
311 CheckLazyArguments();
314 ArgumentListType &getArgumentList() {
315 CheckLazyArguments();
318 static iplist<Argument> Function::*getSublistAccess(Argument*) {
319 return &Function::ArgumentList;
322 const BasicBlockListType &getBasicBlockList() const { return BasicBlocks; }
323 BasicBlockListType &getBasicBlockList() { return BasicBlocks; }
324 static iplist<BasicBlock> Function::*getSublistAccess(BasicBlock*) {
325 return &Function::BasicBlocks;
328 const BasicBlock &getEntryBlock() const { return front(); }
329 BasicBlock &getEntryBlock() { return front(); }
331 //===--------------------------------------------------------------------===//
332 // Symbol Table Accessing functions...
334 /// getSymbolTable() - Return the symbol table...
336 inline ValueSymbolTable &getValueSymbolTable() { return *SymTab; }
337 inline const ValueSymbolTable &getValueSymbolTable() const { return *SymTab; }
340 //===--------------------------------------------------------------------===//
341 // BasicBlock iterator forwarding functions
343 iterator begin() { return BasicBlocks.begin(); }
344 const_iterator begin() const { return BasicBlocks.begin(); }
345 iterator end () { return BasicBlocks.end(); }
346 const_iterator end () const { return BasicBlocks.end(); }
348 size_t size() const { return BasicBlocks.size(); }
349 bool empty() const { return BasicBlocks.empty(); }
350 const BasicBlock &front() const { return BasicBlocks.front(); }
351 BasicBlock &front() { return BasicBlocks.front(); }
352 const BasicBlock &back() const { return BasicBlocks.back(); }
353 BasicBlock &back() { return BasicBlocks.back(); }
355 //===--------------------------------------------------------------------===//
356 // Argument iterator forwarding functions
358 arg_iterator arg_begin() {
359 CheckLazyArguments();
360 return ArgumentList.begin();
362 const_arg_iterator arg_begin() const {
363 CheckLazyArguments();
364 return ArgumentList.begin();
366 arg_iterator arg_end() {
367 CheckLazyArguments();
368 return ArgumentList.end();
370 const_arg_iterator arg_end() const {
371 CheckLazyArguments();
372 return ArgumentList.end();
375 size_t arg_size() const;
376 bool arg_empty() const;
378 /// viewCFG - This function is meant for use from the debugger. You can just
379 /// say 'call F->viewCFG()' and a ghostview window should pop up from the
380 /// program, displaying the CFG of the current function with the code for each
381 /// basic block inside. This depends on there being a 'dot' and 'gv' program
384 void viewCFG() const;
386 /// viewCFGOnly - This function is meant for use from the debugger. It works
387 /// just like viewCFG, but it does not include the contents of basic blocks
388 /// into the nodes, just the label. If you are only interested in the CFG
389 /// this can make the graph smaller.
391 void viewCFGOnly() const;
393 /// Methods for support type inquiry through isa, cast, and dyn_cast:
394 static inline bool classof(const Value *V) {
395 return V->getValueID() == Value::FunctionVal;
398 /// dropAllReferences() - This method causes all the subinstructions to "let
399 /// go" of all references that they are maintaining. This allows one to
400 /// 'delete' a whole module at a time, even though there may be circular
401 /// references... first all references are dropped, and all use counts go to
402 /// zero. Then everything is deleted for real. Note that no operations are
403 /// valid on an object that has "dropped all references", except operator
406 /// Since no other object in the module can have references into the body of a
407 /// function, dropping all references deletes the entire body of the function,
408 /// including any contained basic blocks.
410 void dropAllReferences();
412 /// hasAddressTaken - returns true if there are any uses of this function
413 /// other than direct calls or invokes to it, or blockaddress expressions.
414 /// Optionally passes back an offending user for diagnostic purposes.
416 bool hasAddressTaken(const User** = 0) const;
418 /// isDefTriviallyDead - Return true if it is trivially safe to remove
419 /// this function definition from the module (because it isn't externally
420 /// visible, does not have its address taken, and has no callers). To make
421 /// this more accurate, call removeDeadConstantUsers first.
422 bool isDefTriviallyDead() const;
424 /// callsFunctionThatReturnsTwice - Return true if the function has a call to
425 /// setjmp or other function that gcc recognizes as "returning twice".
426 bool callsFunctionThatReturnsTwice() const;
429 // Shadow Value::setValueSubclassData with a private forwarding method so that
430 // subclasses cannot accidentally use it.
431 void setValueSubclassData(unsigned short D) {
432 Value::setValueSubclassData(D);
436 inline ValueSymbolTable *
437 ilist_traits<BasicBlock>::getSymTab(Function *F) {
438 return F ? &F->getValueSymbolTable() : 0;
441 inline ValueSymbolTable *
442 ilist_traits<Argument>::getSymTab(Function *F) {
443 return F ? &F->getValueSymbolTable() : 0;
446 } // End llvm namespace