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 AttributeSets; ///< 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 /// Do the actual lookup of an intrinsic ID when the query could not be
117 /// answered from the cache.
118 unsigned lookupIntrinsicID() const LLVM_READONLY;
120 /// Function ctor - If the (optional) Module argument is specified, the
121 /// function is automatically inserted into the end of the function list for
124 Function(FunctionType *Ty, LinkageTypes Linkage,
125 const Twine &N = "", Module *M = 0);
128 static Function *Create(FunctionType *Ty, LinkageTypes Linkage,
129 const Twine &N = "", Module *M = 0) {
130 return new(0) Function(Ty, Linkage, N, M);
135 Type *getReturnType() const; // Return the type of the ret val
136 FunctionType *getFunctionType() const; // Return the FunctionType for me
138 /// getContext - Return a pointer to the LLVMContext associated with this
139 /// function, or NULL if this function is not bound to a context yet.
140 LLVMContext &getContext() const;
142 /// isVarArg - Return true if this function takes a variable number of
144 bool isVarArg() const;
146 /// getIntrinsicID - This method returns the ID number of the specified
147 /// function, or Intrinsic::not_intrinsic if the function is not an
148 /// intrinsic, or if the pointer is null. This value is always defined to be
149 /// zero to allow easy checking for whether a function is intrinsic or not.
150 /// The particular intrinsic functions which correspond to this value are
151 /// defined in llvm/Intrinsics.h. Results are cached in the LLVM context,
152 /// subsequent requests for the same ID return results much faster from the
155 unsigned getIntrinsicID() const LLVM_READONLY;
156 bool isIntrinsic() const { return getName().startswith("llvm."); }
158 /// getCallingConv()/setCallingConv(CC) - These method get and set the
159 /// calling convention of this function. The enum values for the known
160 /// calling conventions are defined in CallingConv.h.
161 CallingConv::ID getCallingConv() const {
162 return static_cast<CallingConv::ID>(getSubclassDataFromValue() >> 1);
164 void setCallingConv(CallingConv::ID CC) {
165 setValueSubclassData((getSubclassDataFromValue() & 1) |
166 (static_cast<unsigned>(CC) << 1));
169 /// getAttributes - Return the attribute list for this Function.
171 AttributeSet getAttributes() const { return AttributeSets; }
173 /// setAttributes - Set the attribute list for this Function.
175 void setAttributes(AttributeSet attrs) { AttributeSets = attrs; }
177 /// addFnAttr - Add function attributes to this function.
179 void addFnAttr(Attribute::AttrKind N) {
180 setAttributes(AttributeSets.addAttribute(getContext(),
181 AttributeSet::FunctionIndex, N));
184 /// \brief Return true if the function has the attribute.
185 bool hasFnAttribute(Attribute::AttrKind Kind) const {
186 return AttributeSets.hasAttribute(AttributeSet::FunctionIndex, Kind);
188 bool hasFnAttribute(StringRef Kind) const {
189 return AttributeSets.hasAttribute(AttributeSet::FunctionIndex, Kind);
192 /// hasGC/getGC/setGC/clearGC - The name of the garbage collection algorithm
193 /// to use during code generation.
195 const char *getGC() const;
196 void setGC(const char *Str);
199 /// @brief adds the attribute to the list of attributes.
200 void addAttribute(unsigned i, Attribute::AttrKind attr);
202 /// @brief adds the attributes to the list of attributes.
203 void addAttributes(unsigned i, AttributeSet attrs);
205 /// @brief removes the attributes from the list of attributes.
206 void removeAttributes(unsigned i, AttributeSet attr);
208 /// @brief Extract the alignment for a call or parameter (0=unknown).
209 unsigned getParamAlignment(unsigned i) const {
210 return AttributeSets.getParamAlignment(i);
213 /// @brief Determine if the function does not access memory.
214 bool doesNotAccessMemory() const {
215 return AttributeSets.hasAttribute(AttributeSet::FunctionIndex,
216 Attribute::ReadNone);
218 void setDoesNotAccessMemory() {
219 addFnAttr(Attribute::ReadNone);
222 /// @brief Determine if the function does not access or only reads memory.
223 bool onlyReadsMemory() const {
224 return doesNotAccessMemory() ||
225 AttributeSets.hasAttribute(AttributeSet::FunctionIndex,
226 Attribute::ReadOnly);
228 void setOnlyReadsMemory() {
229 addFnAttr(Attribute::ReadOnly);
232 /// @brief Determine if the function cannot return.
233 bool doesNotReturn() const {
234 return AttributeSets.hasAttribute(AttributeSet::FunctionIndex,
235 Attribute::NoReturn);
237 void setDoesNotReturn() {
238 addFnAttr(Attribute::NoReturn);
241 /// @brief Determine if the function cannot unwind.
242 bool doesNotThrow() const {
243 return AttributeSets.hasAttribute(AttributeSet::FunctionIndex,
244 Attribute::NoUnwind);
246 void setDoesNotThrow() {
247 addFnAttr(Attribute::NoUnwind);
250 /// @brief Determine if the call cannot be duplicated.
251 bool cannotDuplicate() const {
252 return AttributeSets.hasAttribute(AttributeSet::FunctionIndex,
253 Attribute::NoDuplicate);
255 void setCannotDuplicate() {
256 addFnAttr(Attribute::NoDuplicate);
259 /// @brief True if the ABI mandates (or the user requested) that this
260 /// function be in a unwind table.
261 bool hasUWTable() const {
262 return AttributeSets.hasAttribute(AttributeSet::FunctionIndex,
265 void setHasUWTable() {
266 addFnAttr(Attribute::UWTable);
269 /// @brief True if this function needs an unwind table.
270 bool needsUnwindTableEntry() const {
271 return hasUWTable() || !doesNotThrow();
274 /// @brief Determine if the function returns a structure through first
275 /// pointer argument.
276 bool hasStructRetAttr() const {
277 return AttributeSets.hasAttribute(1, Attribute::StructRet);
280 /// @brief Determine if the parameter does not alias other parameters.
281 /// @param n The parameter to check. 1 is the first parameter, 0 is the return
282 bool doesNotAlias(unsigned n) const {
283 return AttributeSets.hasAttribute(n, Attribute::NoAlias);
285 void setDoesNotAlias(unsigned n) {
286 addAttribute(n, Attribute::NoAlias);
289 /// @brief Determine if the parameter can be captured.
290 /// @param n The parameter to check. 1 is the first parameter, 0 is the return
291 bool doesNotCapture(unsigned n) const {
292 return AttributeSets.hasAttribute(n, Attribute::NoCapture);
294 void setDoesNotCapture(unsigned n) {
295 addAttribute(n, Attribute::NoCapture);
298 /// copyAttributesFrom - copy all additional attributes (those not needed to
299 /// create a Function) from the Function Src to this one.
300 void copyAttributesFrom(const GlobalValue *Src);
302 /// deleteBody - This method deletes the body of the function, and converts
303 /// the linkage to external.
307 setLinkage(ExternalLinkage);
310 /// removeFromParent - This method unlinks 'this' from the containing module,
311 /// but does not delete it.
313 virtual void removeFromParent();
315 /// eraseFromParent - This method unlinks 'this' from the containing module
318 virtual void eraseFromParent();
321 /// Get the underlying elements of the Function... the basic block list is
322 /// empty for external functions.
324 const ArgumentListType &getArgumentList() const {
325 CheckLazyArguments();
328 ArgumentListType &getArgumentList() {
329 CheckLazyArguments();
332 static iplist<Argument> Function::*getSublistAccess(Argument*) {
333 return &Function::ArgumentList;
336 const BasicBlockListType &getBasicBlockList() const { return BasicBlocks; }
337 BasicBlockListType &getBasicBlockList() { return BasicBlocks; }
338 static iplist<BasicBlock> Function::*getSublistAccess(BasicBlock*) {
339 return &Function::BasicBlocks;
342 const BasicBlock &getEntryBlock() const { return front(); }
343 BasicBlock &getEntryBlock() { return front(); }
345 //===--------------------------------------------------------------------===//
346 // Symbol Table Accessing functions...
348 /// getSymbolTable() - Return the symbol table...
350 inline ValueSymbolTable &getValueSymbolTable() { return *SymTab; }
351 inline const ValueSymbolTable &getValueSymbolTable() const { return *SymTab; }
354 //===--------------------------------------------------------------------===//
355 // BasicBlock iterator forwarding functions
357 iterator begin() { return BasicBlocks.begin(); }
358 const_iterator begin() const { return BasicBlocks.begin(); }
359 iterator end () { return BasicBlocks.end(); }
360 const_iterator end () const { return BasicBlocks.end(); }
362 size_t size() const { return BasicBlocks.size(); }
363 bool empty() const { return BasicBlocks.empty(); }
364 const BasicBlock &front() const { return BasicBlocks.front(); }
365 BasicBlock &front() { return BasicBlocks.front(); }
366 const BasicBlock &back() const { return BasicBlocks.back(); }
367 BasicBlock &back() { return BasicBlocks.back(); }
369 //===--------------------------------------------------------------------===//
370 // Argument iterator forwarding functions
372 arg_iterator arg_begin() {
373 CheckLazyArguments();
374 return ArgumentList.begin();
376 const_arg_iterator arg_begin() const {
377 CheckLazyArguments();
378 return ArgumentList.begin();
380 arg_iterator arg_end() {
381 CheckLazyArguments();
382 return ArgumentList.end();
384 const_arg_iterator arg_end() const {
385 CheckLazyArguments();
386 return ArgumentList.end();
389 size_t arg_size() const;
390 bool arg_empty() const;
392 /// viewCFG - This function is meant for use from the debugger. You can just
393 /// say 'call F->viewCFG()' and a ghostview window should pop up from the
394 /// program, displaying the CFG of the current function with the code for each
395 /// basic block inside. This depends on there being a 'dot' and 'gv' program
398 void viewCFG() const;
400 /// viewCFGOnly - This function is meant for use from the debugger. It works
401 /// just like viewCFG, but it does not include the contents of basic blocks
402 /// into the nodes, just the label. If you are only interested in the CFG
403 /// this can make the graph smaller.
405 void viewCFGOnly() const;
407 /// Methods for support type inquiry through isa, cast, and dyn_cast:
408 static inline bool classof(const Value *V) {
409 return V->getValueID() == Value::FunctionVal;
412 /// dropAllReferences() - This method causes all the subinstructions to "let
413 /// go" of all references that they are maintaining. This allows one to
414 /// 'delete' a whole module at a time, even though there may be circular
415 /// references... first all references are dropped, and all use counts go to
416 /// zero. Then everything is deleted for real. Note that no operations are
417 /// valid on an object that has "dropped all references", except operator
420 /// Since no other object in the module can have references into the body of a
421 /// function, dropping all references deletes the entire body of the function,
422 /// including any contained basic blocks.
424 void dropAllReferences();
426 /// hasAddressTaken - returns true if there are any uses of this function
427 /// other than direct calls or invokes to it, or blockaddress expressions.
428 /// Optionally passes back an offending user for diagnostic purposes.
430 bool hasAddressTaken(const User** = 0) const;
432 /// isDefTriviallyDead - Return true if it is trivially safe to remove
433 /// this function definition from the module (because it isn't externally
434 /// visible, does not have its address taken, and has no callers). To make
435 /// this more accurate, call removeDeadConstantUsers first.
436 bool isDefTriviallyDead() const;
438 /// callsFunctionThatReturnsTwice - Return true if the function has a call to
439 /// setjmp or other function that gcc recognizes as "returning twice".
440 bool callsFunctionThatReturnsTwice() const;
443 // Shadow Value::setValueSubclassData with a private forwarding method so that
444 // subclasses cannot accidentally use it.
445 void setValueSubclassData(unsigned short D) {
446 Value::setValueSubclassData(D);
450 inline ValueSymbolTable *
451 ilist_traits<BasicBlock>::getSymTab(Function *F) {
452 return F ? &F->getValueSymbolTable() : 0;
455 inline ValueSymbolTable *
456 ilist_traits<Argument>::getSymTab(Function *F) {
457 return F ? &F->getValueSymbolTable() : 0;
460 } // End llvm namespace