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 /// addFnAttr - Add function attributes to this function.
173 void addFnAttr(Attribute::AttrKind N) {
174 // Function Attribute are stored at ~0 index
175 addAttribute(AttributeSet::FunctionIndex, Attribute::get(getContext(), N));
178 /// removeFnAttr - Remove function attributes from this function.
180 void removeFnAttr(Attribute N) {
181 // Function Attribute are stored at ~0 index
182 removeAttribute(~0U, N);
185 /// hasGC/getGC/setGC/clearGC - The name of the garbage collection algorithm
186 /// to use during code generation.
188 const char *getGC() const;
189 void setGC(const char *Str);
192 /// getRetAttributes - Return the return attributes for querying.
193 Attribute getRetAttributes() const {
194 return AttributeList.getRetAttributes();
197 /// addAttribute - adds the attribute to the list of attributes.
198 void addAttribute(unsigned i, Attribute attr);
200 /// removeAttribute - removes the attribute from the list of attributes.
201 void removeAttribute(unsigned i, Attribute attr);
203 /// @brief Extract the alignment for a call or parameter (0=unknown).
204 unsigned getParamAlignment(unsigned i) const {
205 return AttributeList.getParamAlignment(i);
208 /// @brief Determine if the function does not access memory.
209 bool doesNotAccessMemory() const {
210 return AttributeList.hasAttribute(AttributeSet::FunctionIndex,
211 Attribute::ReadNone);
213 void setDoesNotAccessMemory() {
214 addFnAttr(Attribute::ReadNone);
217 /// @brief Determine if the function does not access or only reads memory.
218 bool onlyReadsMemory() const {
219 return doesNotAccessMemory() ||
220 AttributeList.hasAttribute(AttributeSet::FunctionIndex,
221 Attribute::ReadOnly);
223 void setOnlyReadsMemory() {
224 addFnAttr(Attribute::ReadOnly);
227 /// @brief Determine if the function cannot return.
228 bool doesNotReturn() const {
229 return AttributeList.hasAttribute(AttributeSet::FunctionIndex,
230 Attribute::NoReturn);
232 void setDoesNotReturn() {
233 addFnAttr(Attribute::NoReturn);
236 /// @brief Determine if the function cannot unwind.
237 bool doesNotThrow() const {
238 return AttributeList.hasAttribute(AttributeSet::FunctionIndex,
239 Attribute::NoUnwind);
241 void setDoesNotThrow() {
242 addFnAttr(Attribute::NoUnwind);
245 /// @brief Determine if the call cannot be duplicated.
246 bool cannotDuplicate() const {
247 return AttributeList.hasAttribute(AttributeSet::FunctionIndex,
248 Attribute::NoDuplicate);
250 void setCannotDuplicate() {
251 addFnAttr(Attribute::NoDuplicate);
254 /// @brief True if the ABI mandates (or the user requested) that this
255 /// function be in a unwind table.
256 bool hasUWTable() const {
257 return AttributeList.hasAttribute(AttributeSet::FunctionIndex,
260 void setHasUWTable() {
261 addFnAttr(Attribute::UWTable);
264 /// @brief True if this function needs an unwind table.
265 bool needsUnwindTableEntry() const {
266 return hasUWTable() || !doesNotThrow();
269 /// @brief Determine if the function returns a structure through first
270 /// pointer argument.
271 bool hasStructRetAttr() const {
272 return AttributeList.getParamAttributes(1).
273 hasAttribute(Attribute::StructRet);
276 /// @brief Determine if the parameter does not alias other parameters.
277 /// @param n The parameter to check. 1 is the first parameter, 0 is the return
278 bool doesNotAlias(unsigned n) const {
279 return AttributeList.getParamAttributes(n).
280 hasAttribute(Attribute::NoAlias);
282 void setDoesNotAlias(unsigned n) {
283 addAttribute(n, Attribute::get(getContext(), Attribute::NoAlias));
286 /// @brief Determine if the parameter can be captured.
287 /// @param n The parameter to check. 1 is the first parameter, 0 is the return
288 bool doesNotCapture(unsigned n) const {
289 return AttributeList.getParamAttributes(n).
290 hasAttribute(Attribute::NoCapture);
292 void setDoesNotCapture(unsigned n) {
293 addAttribute(n, Attribute::get(getContext(), Attribute::NoCapture));
296 /// copyAttributesFrom - copy all additional attributes (those not needed to
297 /// create a Function) from the Function Src to this one.
298 void copyAttributesFrom(const GlobalValue *Src);
300 /// deleteBody - This method deletes the body of the function, and converts
301 /// the linkage to external.
305 setLinkage(ExternalLinkage);
308 /// removeFromParent - This method unlinks 'this' from the containing module,
309 /// but does not delete it.
311 virtual void removeFromParent();
313 /// eraseFromParent - This method unlinks 'this' from the containing module
316 virtual void eraseFromParent();
319 /// Get the underlying elements of the Function... the basic block list is
320 /// empty for external functions.
322 const ArgumentListType &getArgumentList() const {
323 CheckLazyArguments();
326 ArgumentListType &getArgumentList() {
327 CheckLazyArguments();
330 static iplist<Argument> Function::*getSublistAccess(Argument*) {
331 return &Function::ArgumentList;
334 const BasicBlockListType &getBasicBlockList() const { return BasicBlocks; }
335 BasicBlockListType &getBasicBlockList() { return BasicBlocks; }
336 static iplist<BasicBlock> Function::*getSublistAccess(BasicBlock*) {
337 return &Function::BasicBlocks;
340 const BasicBlock &getEntryBlock() const { return front(); }
341 BasicBlock &getEntryBlock() { return front(); }
343 //===--------------------------------------------------------------------===//
344 // Symbol Table Accessing functions...
346 /// getSymbolTable() - Return the symbol table...
348 inline ValueSymbolTable &getValueSymbolTable() { return *SymTab; }
349 inline const ValueSymbolTable &getValueSymbolTable() const { return *SymTab; }
352 //===--------------------------------------------------------------------===//
353 // BasicBlock iterator forwarding functions
355 iterator begin() { return BasicBlocks.begin(); }
356 const_iterator begin() const { return BasicBlocks.begin(); }
357 iterator end () { return BasicBlocks.end(); }
358 const_iterator end () const { return BasicBlocks.end(); }
360 size_t size() const { return BasicBlocks.size(); }
361 bool empty() const { return BasicBlocks.empty(); }
362 const BasicBlock &front() const { return BasicBlocks.front(); }
363 BasicBlock &front() { return BasicBlocks.front(); }
364 const BasicBlock &back() const { return BasicBlocks.back(); }
365 BasicBlock &back() { return BasicBlocks.back(); }
367 //===--------------------------------------------------------------------===//
368 // Argument iterator forwarding functions
370 arg_iterator arg_begin() {
371 CheckLazyArguments();
372 return ArgumentList.begin();
374 const_arg_iterator arg_begin() const {
375 CheckLazyArguments();
376 return ArgumentList.begin();
378 arg_iterator arg_end() {
379 CheckLazyArguments();
380 return ArgumentList.end();
382 const_arg_iterator arg_end() const {
383 CheckLazyArguments();
384 return ArgumentList.end();
387 size_t arg_size() const;
388 bool arg_empty() const;
390 /// viewCFG - This function is meant for use from the debugger. You can just
391 /// say 'call F->viewCFG()' and a ghostview window should pop up from the
392 /// program, displaying the CFG of the current function with the code for each
393 /// basic block inside. This depends on there being a 'dot' and 'gv' program
396 void viewCFG() const;
398 /// viewCFGOnly - This function is meant for use from the debugger. It works
399 /// just like viewCFG, but it does not include the contents of basic blocks
400 /// into the nodes, just the label. If you are only interested in the CFG
401 /// this can make the graph smaller.
403 void viewCFGOnly() const;
405 /// Methods for support type inquiry through isa, cast, and dyn_cast:
406 static inline bool classof(const Value *V) {
407 return V->getValueID() == Value::FunctionVal;
410 /// dropAllReferences() - This method causes all the subinstructions to "let
411 /// go" of all references that they are maintaining. This allows one to
412 /// 'delete' a whole module at a time, even though there may be circular
413 /// references... first all references are dropped, and all use counts go to
414 /// zero. Then everything is deleted for real. Note that no operations are
415 /// valid on an object that has "dropped all references", except operator
418 /// Since no other object in the module can have references into the body of a
419 /// function, dropping all references deletes the entire body of the function,
420 /// including any contained basic blocks.
422 void dropAllReferences();
424 /// hasAddressTaken - returns true if there are any uses of this function
425 /// other than direct calls or invokes to it, or blockaddress expressions.
426 /// Optionally passes back an offending user for diagnostic purposes.
428 bool hasAddressTaken(const User** = 0) const;
430 /// isDefTriviallyDead - Return true if it is trivially safe to remove
431 /// this function definition from the module (because it isn't externally
432 /// visible, does not have its address taken, and has no callers). To make
433 /// this more accurate, call removeDeadConstantUsers first.
434 bool isDefTriviallyDead() const;
436 /// callsFunctionThatReturnsTwice - Return true if the function has a call to
437 /// setjmp or other function that gcc recognizes as "returning twice".
438 bool callsFunctionThatReturnsTwice() const;
441 // Shadow Value::setValueSubclassData with a private forwarding method so that
442 // subclasses cannot accidentally use it.
443 void setValueSubclassData(unsigned short D) {
444 Value::setValueSubclassData(D);
448 inline ValueSymbolTable *
449 ilist_traits<BasicBlock>::getSymTab(Function *F) {
450 return F ? &F->getValueSymbolTable() : 0;
453 inline ValueSymbolTable *
454 ilist_traits<Argument>::getSymTab(Function *F) {
455 return F ? &F->getValueSymbolTable() : 0;
458 } // End llvm namespace