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//===-- llvm/Function.h - Class to represent a single function --*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the declaration of the Function class, which represents a
// single function/procedure in LLVM.
//
// A function basically consists of a list of basic blocks, a list of arguments,
// and a symbol table.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_IR_FUNCTION_H
#define LLVM_IR_FUNCTION_H
#include "llvm/ADT/ilist_node.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/IR/Argument.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/GlobalObject.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/OperandTraits.h"
#include "llvm/IR/SymbolTableListTraits.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/Compiler.h"
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <memory>
#include <string>
namespace llvm {
template <typename T> class Optional;
class AssemblyAnnotationWriter;
class FunctionType;
class LLVMContext;
class DISubprogram;
class Function : public GlobalObject, public ilist_node<Function> {
public:
typedef SymbolTableList<Argument> ArgumentListType;
typedef SymbolTableList<BasicBlock> BasicBlockListType;
// BasicBlock iterators...
typedef BasicBlockListType::iterator iterator;
typedef BasicBlockListType::const_iterator const_iterator;
typedef ArgumentListType::iterator arg_iterator;
typedef ArgumentListType::const_iterator const_arg_iterator;
private:
// Important things that make up a function!
BasicBlockListType BasicBlocks; ///< The basic blocks
mutable ArgumentListType ArgumentList; ///< The formal arguments
std::unique_ptr<ValueSymbolTable>
SymTab; ///< Symbol table of args/instructions
AttributeSet AttributeSets; ///< Parameter attributes
/*
* Value::SubclassData
*
* bit 0 : HasLazyArguments
* bit 1 : HasPrefixData
* bit 2 : HasPrologueData
* bit 3 : HasPersonalityFn
* bits 4-13 : CallingConvention
* bits 14 : HasGC
* bits 15 : [reserved]
*/
/// Bits from GlobalObject::GlobalObjectSubclassData.
enum {
/// Whether this function is materializable.
IsMaterializableBit = 0,
};
friend class SymbolTableListTraits<Function>;
/// hasLazyArguments/CheckLazyArguments - The argument list of a function is
/// built on demand, so that the list isn't allocated until the first client
/// needs it. The hasLazyArguments predicate returns true if the arg list
/// hasn't been set up yet.
public:
bool hasLazyArguments() const {
return getSubclassDataFromValue() & (1<<0);
}
private:
void CheckLazyArguments() const {
if (hasLazyArguments())
BuildLazyArguments();
}
void BuildLazyArguments() const;
/// Function ctor - If the (optional) Module argument is specified, the
/// function is automatically inserted into the end of the function list for
/// the module.
///
Function(FunctionType *Ty, LinkageTypes Linkage,
const Twine &N = "", Module *M = nullptr);
public:
Function(const Function&) = delete;
void operator=(const Function&) = delete;
~Function() override;
static Function *Create(FunctionType *Ty, LinkageTypes Linkage,
const Twine &N = "", Module *M = nullptr) {
return new Function(Ty, Linkage, N, M);
}
// Provide fast operand accessors.
DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Value);
/// Returns the type of the ret val.
Type *getReturnType() const;
/// Returns the FunctionType for me.
FunctionType *getFunctionType() const;
/// getContext - Return a reference to the LLVMContext associated with this
/// function.
LLVMContext &getContext() const;
/// isVarArg - Return true if this function takes a variable number of
/// arguments.
bool isVarArg() const;
bool isMaterializable() const;
void setIsMaterializable(bool V);
/// getIntrinsicID - This method returns the ID number of the specified
/// function, or Intrinsic::not_intrinsic if the function is not an
/// intrinsic, or if the pointer is null. This value is always defined to be
/// zero to allow easy checking for whether a function is intrinsic or not.
/// The particular intrinsic functions which correspond to this value are
/// defined in llvm/Intrinsics.h.
Intrinsic::ID getIntrinsicID() const LLVM_READONLY { return IntID; }
bool isIntrinsic() const { return getName().startswith("llvm."); }
static Intrinsic::ID lookupIntrinsicID(StringRef Name);
/// \brief Recalculate the ID for this function if it is an Intrinsic defined
/// in llvm/Intrinsics.h. Sets the intrinsic ID to Intrinsic::not_intrinsic
/// if the name of this function does not match an intrinsic in that header.
/// Note, this method does not need to be called directly, as it is called
/// from Value::setName() whenever the name of this function changes.
void recalculateIntrinsicID();
/// getCallingConv()/setCallingConv(CC) - These method get and set the
/// calling convention of this function. The enum values for the known
/// calling conventions are defined in CallingConv.h.
CallingConv::ID getCallingConv() const {
return static_cast<CallingConv::ID>((getSubclassDataFromValue() >> 4) &
CallingConv::MaxID);
}
void setCallingConv(CallingConv::ID CC) {
auto ID = static_cast<unsigned>(CC);
assert(!(ID & ~CallingConv::MaxID) && "Unsupported calling convention");
setValueSubclassData((getSubclassDataFromValue() & 0xc00f) | (ID << 4));
}
/// @brief Return the attribute list for this Function.
AttributeSet getAttributes() const { return AttributeSets; }
/// @brief Set the attribute list for this Function.
void setAttributes(AttributeSet Attrs) { AttributeSets = Attrs; }
/// @brief Add function attributes to this function.
void addFnAttr(Attribute::AttrKind Kind) {
addAttribute(AttributeSet::FunctionIndex, Kind);
}
/// @brief Add function attributes to this function.
void addFnAttr(StringRef Kind, StringRef Val = StringRef()) {
addAttribute(AttributeSet::FunctionIndex,
Attribute::get(getContext(), Kind, Val));
}
void addFnAttr(Attribute Attr) {
addAttribute(AttributeSet::FunctionIndex, Attr);
}
/// @brief Remove function attributes from this function.
void removeFnAttr(Attribute::AttrKind Kind) {
removeAttribute(AttributeSet::FunctionIndex, Kind);
}
/// @brief Remove function attribute from this function.
void removeFnAttr(StringRef Kind) {
setAttributes(AttributeSets.removeAttribute(
getContext(), AttributeSet::FunctionIndex, Kind));
}
/// \brief Set the entry count for this function.
///
/// Entry count is the number of times this function was executed based on
/// pgo data.
void setEntryCount(uint64_t Count);
/// \brief Get the entry count for this function.
///
/// Entry count is the number of times the function was executed based on
/// pgo data.
Optional<uint64_t> getEntryCount() const;
/// Set the section prefix for this function.
void setSectionPrefix(StringRef Prefix);
/// Get the section prefix for this function.
Optional<StringRef> getSectionPrefix() const;
/// @brief Return true if the function has the attribute.
bool hasFnAttribute(Attribute::AttrKind Kind) const {
return AttributeSets.hasFnAttribute(Kind);
}
bool hasFnAttribute(StringRef Kind) const {
return AttributeSets.hasFnAttribute(Kind);
}
/// @brief Return the attribute for the given attribute kind.
Attribute getFnAttribute(Attribute::AttrKind Kind) const {
return getAttribute(AttributeSet::FunctionIndex, Kind);
}
Attribute getFnAttribute(StringRef Kind) const {
return getAttribute(AttributeSet::FunctionIndex, Kind);
}
/// \brief Return the stack alignment for the function.
unsigned getFnStackAlignment() const {
if (!hasFnAttribute(Attribute::StackAlignment))
return 0;
return AttributeSets.getStackAlignment(AttributeSet::FunctionIndex);
}
/// hasGC/getGC/setGC/clearGC - The name of the garbage collection algorithm
/// to use during code generation.
bool hasGC() const {
return getSubclassDataFromValue() & (1<<14);
}
const std::string &getGC() const;
void setGC(std::string Str);
void clearGC();
/// @brief adds the attribute to the list of attributes.
void addAttribute(unsigned i, Attribute::AttrKind Kind);
/// @brief adds the attribute to the list of attributes.
void addAttribute(unsigned i, Attribute Attr);
/// @brief adds the attributes to the list of attributes.
void addAttributes(unsigned i, AttributeSet Attrs);
/// @brief removes the attribute from the list of attributes.
void removeAttribute(unsigned i, Attribute::AttrKind Kind);
/// @brief removes the attribute from the list of attributes.
void removeAttribute(unsigned i, StringRef Kind);
/// @brief removes the attributes from the list of attributes.
void removeAttributes(unsigned i, AttributeSet Attrs);
/// @brief check if an attributes is in the list of attributes.
bool hasAttribute(unsigned i, Attribute::AttrKind Kind) const {
return getAttributes().hasAttribute(i, Kind);
}
Attribute getAttribute(unsigned i, Attribute::AttrKind Kind) const {
return AttributeSets.getAttribute(i, Kind);
}
Attribute getAttribute(unsigned i, StringRef Kind) const {
return AttributeSets.getAttribute(i, Kind);
}
/// @brief adds the dereferenceable attribute to the list of attributes.
void addDereferenceableAttr(unsigned i, uint64_t Bytes);
/// @brief adds the dereferenceable_or_null attribute to the list of
/// attributes.
void addDereferenceableOrNullAttr(unsigned i, uint64_t Bytes);
/// @brief Extract the alignment for a call or parameter (0=unknown).
unsigned getParamAlignment(unsigned i) const {
return AttributeSets.getParamAlignment(i);
}
/// @brief Extract the number of dereferenceable bytes for a call or
/// parameter (0=unknown).
uint64_t getDereferenceableBytes(unsigned i) const {
return AttributeSets.getDereferenceableBytes(i);
}
/// @brief Extract the number of dereferenceable_or_null bytes for a call or
/// parameter (0=unknown).
uint64_t getDereferenceableOrNullBytes(unsigned i) const {
return AttributeSets.getDereferenceableOrNullBytes(i);
}
/// @brief Determine if the function does not access memory.
bool doesNotAccessMemory() const {
return hasFnAttribute(Attribute::ReadNone);
}
void setDoesNotAccessMemory() {
addFnAttr(Attribute::ReadNone);
}
/// @brief Determine if the function does not access or only reads memory.
bool onlyReadsMemory() const {
return doesNotAccessMemory() || hasFnAttribute(Attribute::ReadOnly);
}
void setOnlyReadsMemory() {
addFnAttr(Attribute::ReadOnly);
}
/// @brief Determine if the function does not access or only writes memory.
bool doesNotReadMemory() const {
return doesNotAccessMemory() || hasFnAttribute(Attribute::WriteOnly);
}
void setDoesNotReadMemory() {
addFnAttr(Attribute::WriteOnly);
}
/// @brief Determine if the call can access memmory only using pointers based
/// on its arguments.
bool onlyAccessesArgMemory() const {
return hasFnAttribute(Attribute::ArgMemOnly);
}
void setOnlyAccessesArgMemory() { addFnAttr(Attribute::ArgMemOnly); }
/// @brief Determine if the function may only access memory that is
/// inaccessible from the IR.
bool onlyAccessesInaccessibleMemory() const {
return hasFnAttribute(Attribute::InaccessibleMemOnly);
}
void setOnlyAccessesInaccessibleMemory() {
addFnAttr(Attribute::InaccessibleMemOnly);
}
/// @brief Determine if the function may only access memory that is
/// either inaccessible from the IR or pointed to by its arguments.
bool onlyAccessesInaccessibleMemOrArgMem() const {
return hasFnAttribute(Attribute::InaccessibleMemOrArgMemOnly);
}
void setOnlyAccessesInaccessibleMemOrArgMem() {
addFnAttr(Attribute::InaccessibleMemOrArgMemOnly);
}
/// @brief Determine if the function cannot return.
bool doesNotReturn() const {
return hasFnAttribute(Attribute::NoReturn);
}
void setDoesNotReturn() {
addFnAttr(Attribute::NoReturn);
}
/// @brief Determine if the function cannot unwind.
bool doesNotThrow() const {
return hasFnAttribute(Attribute::NoUnwind);
}
void setDoesNotThrow() {
addFnAttr(Attribute::NoUnwind);
}
/// @brief Determine if the call cannot be duplicated.
bool cannotDuplicate() const {
return hasFnAttribute(Attribute::NoDuplicate);
}
void setCannotDuplicate() {
addFnAttr(Attribute::NoDuplicate);
}
/// @brief Determine if the call is convergent.
bool isConvergent() const {
return hasFnAttribute(Attribute::Convergent);
}
void setConvergent() {
addFnAttr(Attribute::Convergent);
}
void setNotConvergent() {
removeFnAttr(Attribute::Convergent);
}
/// Determine if the function is known not to recurse, directly or
/// indirectly.
bool doesNotRecurse() const {
return hasFnAttribute(Attribute::NoRecurse);
}
void setDoesNotRecurse() {
addFnAttr(Attribute::NoRecurse);
}
/// @brief True if the ABI mandates (or the user requested) that this
/// function be in a unwind table.
bool hasUWTable() const {
return hasFnAttribute(Attribute::UWTable);
}
void setHasUWTable() {
addFnAttr(Attribute::UWTable);
}
/// @brief True if this function needs an unwind table.
bool needsUnwindTableEntry() const {
return hasUWTable() || !doesNotThrow();
}
/// @brief Determine if the function returns a structure through first
/// pointer argument.
bool hasStructRetAttr() const {
return AttributeSets.hasAttribute(1, Attribute::StructRet) ||
AttributeSets.hasAttribute(2, Attribute::StructRet);
}
/// @brief Determine if the parameter or return value is marked with NoAlias
/// attribute.
/// @param n The parameter to check. 1 is the first parameter, 0 is the return
bool doesNotAlias(unsigned n) const {
return AttributeSets.hasAttribute(n, Attribute::NoAlias);
}
void setDoesNotAlias(unsigned n) {
addAttribute(n, Attribute::NoAlias);
}
/// @brief Determine if the parameter can be captured.
/// @param n The parameter to check. 1 is the first parameter, 0 is the return
bool doesNotCapture(unsigned n) const {
return AttributeSets.hasAttribute(n, Attribute::NoCapture);
}
void setDoesNotCapture(unsigned n) {
addAttribute(n, Attribute::NoCapture);
}
bool doesNotAccessMemory(unsigned n) const {
return AttributeSets.hasAttribute(n, Attribute::ReadNone);
}
void setDoesNotAccessMemory(unsigned n) {
addAttribute(n, Attribute::ReadNone);
}
bool onlyReadsMemory(unsigned n) const {
return doesNotAccessMemory(n) ||
AttributeSets.hasAttribute(n, Attribute::ReadOnly);
}
void setOnlyReadsMemory(unsigned n) {
addAttribute(n, Attribute::ReadOnly);
}
/// Optimize this function for minimum size (-Oz).
bool optForMinSize() const { return hasFnAttribute(Attribute::MinSize); }
/// Optimize this function for size (-Os) or minimum size (-Oz).
bool optForSize() const {
return hasFnAttribute(Attribute::OptimizeForSize) || optForMinSize();
}
/// copyAttributesFrom - copy all additional attributes (those not needed to
/// create a Function) from the Function Src to this one.
void copyAttributesFrom(const GlobalValue *Src) override;
/// deleteBody - This method deletes the body of the function, and converts
/// the linkage to external.
///
void deleteBody() {
dropAllReferences();
setLinkage(ExternalLinkage);
}
/// removeFromParent - This method unlinks 'this' from the containing module,
/// but does not delete it.
///
void removeFromParent() override;
/// eraseFromParent - This method unlinks 'this' from the containing module
/// and deletes it.
///
void eraseFromParent() override;
/// Steal arguments from another function.
///
/// Drop this function's arguments and splice in the ones from \c Src.
/// Requires that this has no function body.
void stealArgumentListFrom(Function &Src);
/// Get the underlying elements of the Function... the basic block list is
/// empty for external functions.
///
const ArgumentListType &getArgumentList() const {
CheckLazyArguments();
return ArgumentList;
}
ArgumentListType &getArgumentList() {
CheckLazyArguments();
return ArgumentList;
}
static ArgumentListType Function::*getSublistAccess(Argument*) {
return &Function::ArgumentList;
}
const BasicBlockListType &getBasicBlockList() const { return BasicBlocks; }
BasicBlockListType &getBasicBlockList() { return BasicBlocks; }
static BasicBlockListType Function::*getSublistAccess(BasicBlock*) {
return &Function::BasicBlocks;
}
const BasicBlock &getEntryBlock() const { return front(); }
BasicBlock &getEntryBlock() { return front(); }
//===--------------------------------------------------------------------===//
// Symbol Table Accessing functions...
/// getSymbolTable() - Return the symbol table if any, otherwise nullptr.
///
inline ValueSymbolTable *getValueSymbolTable() { return SymTab.get(); }
inline const ValueSymbolTable *getValueSymbolTable() const {
return SymTab.get();
}
//===--------------------------------------------------------------------===//
// BasicBlock iterator forwarding functions
//
iterator begin() { return BasicBlocks.begin(); }
const_iterator begin() const { return BasicBlocks.begin(); }
iterator end () { return BasicBlocks.end(); }
const_iterator end () const { return BasicBlocks.end(); }
size_t size() const { return BasicBlocks.size(); }
bool empty() const { return BasicBlocks.empty(); }
const BasicBlock &front() const { return BasicBlocks.front(); }
BasicBlock &front() { return BasicBlocks.front(); }
const BasicBlock &back() const { return BasicBlocks.back(); }
BasicBlock &back() { return BasicBlocks.back(); }
/// @name Function Argument Iteration
/// @{
arg_iterator arg_begin() {
CheckLazyArguments();
return ArgumentList.begin();
}
const_arg_iterator arg_begin() const {
CheckLazyArguments();
return ArgumentList.begin();
}
arg_iterator arg_end() {
CheckLazyArguments();
return ArgumentList.end();
}
const_arg_iterator arg_end() const {
CheckLazyArguments();
return ArgumentList.end();
}
iterator_range<arg_iterator> args() {
return make_range(arg_begin(), arg_end());
}
iterator_range<const_arg_iterator> args() const {
return make_range(arg_begin(), arg_end());
}
/// @}
size_t arg_size() const;
bool arg_empty() const;
/// \brief Check whether this function has a personality function.
bool hasPersonalityFn() const {
return getSubclassDataFromValue() & (1<<3);
}
/// \brief Get the personality function associated with this function.
Constant *getPersonalityFn() const;
void setPersonalityFn(Constant *Fn);
/// \brief Check whether this function has prefix data.
bool hasPrefixData() const {
return getSubclassDataFromValue() & (1<<1);
}
/// \brief Get the prefix data associated with this function.
Constant *getPrefixData() const;
void setPrefixData(Constant *PrefixData);
/// \brief Check whether this function has prologue data.
bool hasPrologueData() const {
return getSubclassDataFromValue() & (1<<2);
}
/// \brief Get the prologue data associated with this function.
Constant *getPrologueData() const;
void setPrologueData(Constant *PrologueData);
/// Print the function to an output stream with an optional
/// AssemblyAnnotationWriter.
void print(raw_ostream &OS, AssemblyAnnotationWriter *AAW = nullptr,
bool ShouldPreserveUseListOrder = false,
bool IsForDebug = false) const;
/// viewCFG - This function is meant for use from the debugger. You can just
/// say 'call F->viewCFG()' and a ghostview window should pop up from the
/// program, displaying the CFG of the current function with the code for each
/// basic block inside. This depends on there being a 'dot' and 'gv' program
/// in your path.
///
void viewCFG() const;
/// viewCFGOnly - This function is meant for use from the debugger. It works
/// just like viewCFG, but it does not include the contents of basic blocks
/// into the nodes, just the label. If you are only interested in the CFG
/// this can make the graph smaller.
///
void viewCFGOnly() const;
/// Methods for support type inquiry through isa, cast, and dyn_cast:
static inline bool classof(const Value *V) {
return V->getValueID() == Value::FunctionVal;
}
/// dropAllReferences() - This method causes all the subinstructions to "let
/// go" of all references that they are maintaining. This allows one to
/// 'delete' a whole module at a time, even though there may be circular
/// references... first all references are dropped, and all use counts go to
/// zero. Then everything is deleted for real. Note that no operations are
/// valid on an object that has "dropped all references", except operator
/// delete.
///
/// Since no other object in the module can have references into the body of a
/// function, dropping all references deletes the entire body of the function,
/// including any contained basic blocks.
///
void dropAllReferences();
/// hasAddressTaken - returns true if there are any uses of this function
/// other than direct calls or invokes to it, or blockaddress expressions.
/// Optionally passes back an offending user for diagnostic purposes.
///
bool hasAddressTaken(const User** = nullptr) const;
/// isDefTriviallyDead - Return true if it is trivially safe to remove
/// this function definition from the module (because it isn't externally
/// visible, does not have its address taken, and has no callers). To make
/// this more accurate, call removeDeadConstantUsers first.
bool isDefTriviallyDead() const;
/// callsFunctionThatReturnsTwice - Return true if the function has a call to
/// setjmp or other function that gcc recognizes as "returning twice".
bool callsFunctionThatReturnsTwice() const;
/// \brief Set the attached subprogram.
///
/// Calls \a setMetadata() with \a LLVMContext::MD_dbg.
void setSubprogram(DISubprogram *SP);
/// \brief Get the attached subprogram.
///
/// Calls \a getMetadata() with \a LLVMContext::MD_dbg and casts the result
/// to \a DISubprogram.
DISubprogram *getSubprogram() const;
private:
void allocHungoffUselist();
template<int Idx> void setHungoffOperand(Constant *C);
/// Shadow Value::setValueSubclassData with a private forwarding method so
/// that subclasses cannot accidentally use it.
void setValueSubclassData(unsigned short D) {
Value::setValueSubclassData(D);
}
void setValueSubclassDataBit(unsigned Bit, bool On);
};
template <>
struct OperandTraits<Function> : public HungoffOperandTraits<3> {};
DEFINE_TRANSPARENT_OPERAND_ACCESSORS(Function, Value)
} // end namespace llvm
#endif // LLVM_IR_FUNCTION_H