FunctionAttrs.cpp File Reference

This file implements interprocedural passes which walk the call-graph deducing and/or propagating function attributes. More...

#include "llvm/Transforms/IPO/FunctionAttrs.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/SCCIterator.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/BasicAliasAnalysis.h"
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/CGSCCPassManager.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Analysis/CallGraphSCCPass.h"
#include "llvm/Analysis/CaptureTracking.h"
#include "llvm/Analysis/LazyCallGraph.h"
#include "llvm/Analysis/MemoryLocation.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/Argument.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/ConstantRangeList.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Metadata.h"
#include "llvm/IR/ModuleSummaryIndex.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/Use.h"
#include "llvm/IR/User.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Utils/Local.h"
#include <cassert>
#include <iterator>
#include <map>
#include <optional>
#include <vector>

Go to the source code of this file.

Classes
struct	llvm::GraphTraits< ArgumentGraphNode * >
struct	llvm::GraphTraits< ArgumentGraph * >

Namespaces
namespace	llvm
	This is an optimization pass for GlobalISel generic memory operations.

Macros
#define	DEBUG_TYPE   "function-attrs"

Functions
	STATISTIC (NumMemoryAttr, "Number of functions with improved memory attribute")
	STATISTIC (NumNoCapture, "Number of arguments marked nocapture")
	STATISTIC (NumReturned, "Number of arguments marked returned")
	STATISTIC (NumReadNoneArg, "Number of arguments marked readnone")
	STATISTIC (NumReadOnlyArg, "Number of arguments marked readonly")
	STATISTIC (NumWriteOnlyArg, "Number of arguments marked writeonly")
	STATISTIC (NumNoAlias, "Number of function returns marked noalias")
	STATISTIC (NumNonNullReturn, "Number of function returns marked nonnull")
	STATISTIC (NumNoUndefReturn, "Number of function returns marked noundef")
	STATISTIC (NumNoRecurse, "Number of functions marked as norecurse")
	STATISTIC (NumNoUnwind, "Number of functions marked as nounwind")
	STATISTIC (NumNoFree, "Number of functions marked as nofree")
	STATISTIC (NumWillReturn, "Number of functions marked as willreturn")
	STATISTIC (NumNoSync, "Number of functions marked as nosync")
	STATISTIC (NumCold, "Number of functions marked as cold")
	STATISTIC (NumThinLinkNoRecurse, "Number of functions marked as norecurse during thinlink")
	STATISTIC (NumThinLinkNoUnwind, "Number of functions marked as nounwind during thinlink")
static void	addLocAccess (MemoryEffects &ME, const MemoryLocation &Loc, ModRefInfo MR, AAResults &AAR)
static void	addArgLocs (MemoryEffects &ME, const CallBase *Call, ModRefInfo ArgMR, AAResults &AAR)
static std::pair< MemoryEffects, MemoryEffects >	checkFunctionMemoryAccess (Function &F, bool ThisBody, AAResults &AAR, const SCCNodeSet &SCCNodes)
	Returns the memory access attribute for function F using AAR for AA results, where SCCNodes is the current SCC.
template<typename AARGetterT >
static void	addMemoryAttrs (const SCCNodeSet &SCCNodes, AARGetterT &&AARGetter, SmallSet< Function *, 8 > &Changed)
	Deduce readonly/readnone/writeonly attributes for the SCC.
static FunctionSummary *	calculatePrevailingSummary (ValueInfo VI, DenseMap< ValueInfo, FunctionSummary * > &CachedPrevailingSummary, function_ref< bool(GlobalValue::GUID, const GlobalValueSummary *)> IsPrevailing)
static Attribute::AttrKind	determinePointerAccessAttrs (Argument *A, const SmallPtrSet< Argument *, 8 > &SCCNodes)
	Returns Attribute::None, Attribute::ReadOnly or Attribute::ReadNone.
static void	addArgumentReturnedAttrs (const SCCNodeSet &SCCNodes, SmallSet< Function *, 8 > &Changed)
	Deduce returned attributes for the SCC.
static bool	addArgumentAttrsFromCallsites (Function &F)
	If a callsite has arguments that are also arguments to the parent function, try to propagate attributes from the callsite's arguments to the parent's arguments.
static bool	addAccessAttr (Argument *A, Attribute::AttrKind R)
static bool	inferInitializes (Argument &A, Function &F)
static void	addArgumentAttrs (const SCCNodeSet &SCCNodes, SmallSet< Function *, 8 > &Changed, bool SkipInitializes)
	Deduce nocapture attributes for the SCC.
static bool	isFunctionMallocLike (Function *F, const SCCNodeSet &SCCNodes)
	Tests whether a function is "malloc-like".
static void	addNoAliasAttrs (const SCCNodeSet &SCCNodes, SmallSet< Function *, 8 > &Changed)
	Deduce noalias attributes for the SCC.
static bool	isReturnNonNull (Function *F, const SCCNodeSet &SCCNodes, bool &Speculative)
	Tests whether this function is known to not return null.
static void	addNonNullAttrs (const SCCNodeSet &SCCNodes, SmallSet< Function *, 8 > &Changed)
	Deduce nonnull attributes for the SCC.
static void	addNoUndefAttrs (const SCCNodeSet &SCCNodes, SmallSet< Function *, 8 > &Changed)
	Deduce noundef attributes for the SCC.
static bool	InstrBreaksNonConvergent (Instruction &I, const SCCNodeSet &SCCNodes)
	Helper for non-Convergent inference predicate InstrBreaksAttribute.
static bool	InstrBreaksNonThrowing (Instruction &I, const SCCNodeSet &SCCNodes)
	Helper for NoUnwind inference predicate InstrBreaksAttribute.
static bool	InstrBreaksNoFree (Instruction &I, const SCCNodeSet &SCCNodes)
	Helper for NoFree inference predicate InstrBreaksAttribute.
static bool	isOrderedAtomic (Instruction *I)
static bool	InstrBreaksNoSync (Instruction &I, const SCCNodeSet &SCCNodes)
static void	inferConvergent (const SCCNodeSet &SCCNodes, SmallSet< Function *, 8 > &Changed)
	Attempt to remove convergent function attribute when possible.
static void	inferAttrsFromFunctionBodies (const SCCNodeSet &SCCNodes, SmallSet< Function *, 8 > &Changed)
	Infer attributes from all functions in the SCC by scanning every instruction for compliance to the attribute assumptions.
static void	addNoRecurseAttrs (const SCCNodeSet &SCCNodes, SmallSet< Function *, 8 > &Changed)
static bool	instructionDoesNotReturn (Instruction &I)
static bool	basicBlockCanReturn (BasicBlock &BB)
static bool	canReturn (Function &F)
static void	addNoReturnAttrs (const SCCNodeSet &SCCNodes, SmallSet< Function *, 8 > &Changed)
static bool	allPathsGoThroughCold (Function &F)
static void	addColdAttrs (const SCCNodeSet &SCCNodes, SmallSet< Function *, 8 > &Changed)
static bool	functionWillReturn (const Function &F)
static void	addWillReturn (const SCCNodeSet &SCCNodes, SmallSet< Function *, 8 > &Changed)
static SCCNodesResult	createSCCNodeSet (ArrayRef< Function * > Functions)
template<typename AARGetterT >
static SmallSet< Function *, 8 >	deriveAttrsInPostOrder (ArrayRef< Function * > Functions, AARGetterT &&AARGetter, bool ArgAttrsOnly)
template<typename AARGetterT >
static bool	runImpl (CallGraphSCC &SCC, AARGetterT AARGetter)
static bool	addNoRecurseAttrsTopDown (Function &F)
static bool	deduceFunctionAttributeInRPO (Module &M, LazyCallGraph &CG)

Variables
static cl::opt< bool >	EnableNonnullArgPropagation ("enable-nonnull-arg-prop", cl::init(true), cl::Hidden, cl::desc("Try to propagate nonnull argument attributes from callsites to " "caller functions."))
static cl::opt< bool >	DisableNoUnwindInference ("disable-nounwind-inference", cl::Hidden, cl::desc("Stop inferring nounwind attribute during function-attrs pass"))
static cl::opt< bool >	DisableNoFreeInference ("disable-nofree-inference", cl::Hidden, cl::desc("Stop inferring nofree attribute during function-attrs pass"))
static cl::opt< bool >	DisableThinLTOPropagation ("disable-thinlto-funcattrs", cl::init(true), cl::Hidden, cl::desc("Don't propagate function-attrs in thinLTO"))

Detailed Description

This file implements interprocedural passes which walk the call-graph deducing and/or propagating function attributes.

Definition in file FunctionAttrs.cpp.

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "function-attrs"

Definition at line 71 of file FunctionAttrs.cpp.

Function Documentation

addAccessAttr()

static bool addAccessAttr ( Argument *  A, Attribute::AttrKind  R  )

static

Definition at line 1040 of file FunctionAttrs.cpp.

References A, and assert().

Referenced by addArgumentAttrs().

addArgLocs()

static void addArgLocs ( MemoryEffects &  ME, const CallBase *  Call, ModRefInfo  ArgMR, AAResults &  AAR  )

static

Definition at line 138 of file FunctionAttrs.cpp.

References addLocAccess(), and llvm::MemoryLocation::getBeforeOrAfter().

Referenced by checkFunctionMemoryAccess().

addArgumentAttrs()

static void addArgumentAttrs ( const SCCNodeSet &  SCCNodes, SmallSet< Function *, 8 > &  Changed, bool  SkipInitializes  )

static

Deduce nocapture attributes for the SCC.

Definition at line 1188 of file FunctionAttrs.cpp.

References A, addAccessAttr(), addArgumentAttrsFromCallsites(), B, llvm::SmallPtrSetImpl< PtrType >::count(), determinePointerAccessAttrs(), F, I, inferInitializes(), llvm::SmallSet< T, N, C >::insert(), llvm::SmallPtrSetImpl< PtrType >::insert(), N, llvm::Attribute::None, llvm::PointerMayBeCaptured(), llvm::scc_begin(), and Uses.

Referenced by deriveAttrsInPostOrder().

addArgumentAttrsFromCallsites()

static bool addArgumentAttrsFromCallsites ( Function &  F )

static

If a callsite has arguments that are also arguments to the parent function, try to propagate attributes from the callsite's arguments to the parent's arguments.

This may be important because inlining can cause information loss when attribute knowledge disappears with the inlined call.

Definition at line 1001 of file FunctionAttrs.cpp.

References EnableNonnullArgPropagation, F, llvm::CallBase::getArgOperand(), llvm::CallBase::getCalledFunction(), I, and llvm::isGuaranteedToTransferExecutionToSuccessor().

Referenced by addArgumentAttrs().

addArgumentReturnedAttrs()

static void addArgumentReturnedAttrs ( const SCCNodeSet &  SCCNodes, SmallSet< Function *, 8 > &  Changed  )

static

Deduce returned attributes for the SCC.

Definition at line 952 of file FunctionAttrs.cpp.

References llvm::Argument::addAttr(), F, and llvm::SmallSet< T, N, C >::insert().

Referenced by deriveAttrsInPostOrder().

addColdAttrs()

static void addColdAttrs ( const SCCNodeSet &  SCCNodes, SmallSet< Function *, 8 > &  Changed  )

static

Definition at line 2134 of file FunctionAttrs.cpp.

References allPathsGoThroughCold(), F, and llvm::SmallSet< T, N, C >::insert().

Referenced by deriveAttrsInPostOrder().

addLocAccess()

static void addLocAccess ( MemoryEffects &  ME, const MemoryLocation &  Loc, ModRefInfo  MR, AAResults &  AAR  )

static

Definition at line 117 of file FunctionAttrs.cpp.

References llvm::MemoryEffectsBase< LocationEnum >::argMemOnly(), llvm::AAResults::getModRefInfoMask(), llvm::getUnderlyingObjectAggressive(), llvm::isIdentifiedObject(), llvm::isNoModRef(), and llvm::MemoryLocation::Ptr.

Referenced by addArgLocs(), and checkFunctionMemoryAccess().

addMemoryAttrs()

template<typename AARGetterT >

static void addMemoryAttrs ( const SCCNodeSet &  SCCNodes, AARGetterT &&  AARGetter, SmallSet< Function *, 8 > &  Changed  )

static

Deduce readonly/readnone/writeonly attributes for the SCC.

Definition at line 262 of file FunctionAttrs.cpp.

References A, checkFunctionMemoryAccess(), F, llvm::MemoryEffectsBase< LocationEnum >::getModRef(), llvm::SmallSet< T, N, C >::insert(), llvm::isModSet(), llvm::MemoryEffectsBase< LocationEnum >::none(), and llvm::MemoryEffectsBase< LocationEnum >::unknown().

Referenced by deriveAttrsInPostOrder().

addNoAliasAttrs()

static void addNoAliasAttrs ( const SCCNodeSet &  SCCNodes, SmallSet< Function *, 8 > &  Changed  )

static

Deduce noalias attributes for the SCC.

Definition at line 1442 of file FunctionAttrs.cpp.

References F, llvm::SmallSet< T, N, C >::insert(), and isFunctionMallocLike().

Referenced by deriveAttrsInPostOrder().

addNonNullAttrs()

static void addNonNullAttrs ( const SCCNodeSet &  SCCNodes, SmallSet< Function *, 8 > &  Changed  )

static

Deduce nonnull attributes for the SCC.

Definition at line 1555 of file FunctionAttrs.cpp.

References llvm::dbgs(), F, llvm::SmallSet< T, N, C >::insert(), isReturnNonNull(), and LLVM_DEBUG.

Referenced by deriveAttrsInPostOrder().

addNoRecurseAttrs()

static void addNoRecurseAttrs ( const SCCNodeSet &  SCCNodes, SmallSet< Function *, 8 > &  Changed  )

static

Definition at line 2002 of file FunctionAttrs.cpp.

References F, llvm::CallBase::getCalledFunction(), I, and llvm::SmallSet< T, N, C >::insert().

Referenced by deriveAttrsInPostOrder().

addNoRecurseAttrsTopDown()

static bool addNoRecurseAttrsTopDown ( Function &  F )

static

Definition at line 2350 of file FunctionAttrs.cpp.

References assert(), F, llvm::ilist_detail::node_parent_access< NodeTy, ParentTy >::getParent(), I, and llvm::CallBase::isCallee().

Referenced by deduceFunctionAttributeInRPO().

addNoReturnAttrs()

static void addNoReturnAttrs ( const SCCNodeSet &  SCCNodes, SmallSet< Function *, 8 > &  Changed  )

static

Definition at line 2073 of file FunctionAttrs.cpp.

References canReturn(), F, and llvm::SmallSet< T, N, C >::insert().

Referenced by deriveAttrsInPostOrder().

addNoUndefAttrs()

static void addNoUndefAttrs ( const SCCNodeSet &  SCCNodes, SmallSet< Function *, 8 > &  Changed  )

static

Deduce noundef attributes for the SCC.

Definition at line 1612 of file FunctionAttrs.cpp.

References llvm::all_of(), DL, F, llvm::BasicBlock::getTerminator(), and llvm::SmallSet< T, N, C >::insert().

Referenced by deriveAttrsInPostOrder().

addWillReturn()

static void addWillReturn ( const SCCNodeSet &  SCCNodes, SmallSet< Function *, 8 > &  Changed  )

static

Definition at line 2181 of file FunctionAttrs.cpp.

References F, functionWillReturn(), and llvm::SmallSet< T, N, C >::insert().

Referenced by deriveAttrsInPostOrder().

allPathsGoThroughCold()

static bool allPathsGoThroughCold ( Function &  F )

static

Definition at line 2087 of file FunctionAttrs.cpp.

References llvm::any_of(), llvm::SmallVectorBase< Size_T >::empty(), F, llvm::CallBase::hasFnAttr(), I, llvm::SmallVectorImpl< T >::pop_back_val(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::successors(), and llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::try_emplace().

Referenced by addColdAttrs().

basicBlockCanReturn()

static bool basicBlockCanReturn ( BasicBlock &  BB )

static

Definition at line 2045 of file FunctionAttrs.cpp.

References llvm::BasicBlock::getTerminator(), instructionDoesNotReturn(), and llvm::none_of().

Referenced by canReturn().

calculatePrevailingSummary()

static FunctionSummary * calculatePrevailingSummary ( ValueInfo  VI, DenseMap< ValueInfo, FunctionSummary * > &  CachedPrevailingSummary, function_ref< bool(GlobalValue::GUID, const GlobalValueSummary *)>  IsPrevailing  )

static

At this point, prevailing symbols have been resolved. The following leads to returning a conservative result:

• Multiple instances with local linkage. Normally local linkage would be unique per module as the GUID includes the module path. We could have a guid alias if there wasn't any distinguishing path when each file was compiled, but that should be rare so we'll punt on those.

These next 2 cases should not happen and will assert:

• Multiple instances with external linkage. This should be caught in symbol resolution
• Non-existent FunctionSummary for Aliasee. This presents a hole in our knowledge meaning we have to go conservative.

Otherwise, we calculate attributes for a function as:

1. If we have a local linkage, take its attributes. If there's somehow multiple, bail and go conservative.
2. If we have an external/WeakODR/LinkOnceODR linkage check that it is prevailing, take its attributes.
3. If we have a Weak/LinkOnce linkage the copies can have semantic differences. However, if the prevailing copy is known it will be used so take its attributes. If the prevailing copy is in a native file all IR copies will be dead and propagation will go conservative.
4. AvailableExternally summaries without a prevailing copy are known to occur in a couple of circumstances: a. An internal function gets imported due to its caller getting imported, it becomes AvailableExternally but no prevailing definition exists. Because it has to get imported along with its caller the attributes will be captured by propagating on its caller. b. C++11 [temp.explicit]p10 can generate AvailableExternally definitions of explicitly instanced template declarations for inlining which are ultimately dropped from the TU. Since this is localized to the TU the attributes will have already made it to the callers. These are edge cases and already captured by their callers so we ignore these for now. If they become relevant to optimize in the future this can be revisited.
5. Otherwise, go conservative.

Definition at line 303 of file FunctionAttrs.cpp.

References assert(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::count(), llvm::dbgs(), llvm::GlobalValue::isAvailableExternallyLinkage(), llvm::GlobalValue::isExternalLinkage(), llvm::GlobalValue::isLinkOnceAnyLinkage(), llvm::GlobalValue::isLinkOnceODRLinkage(), llvm::GlobalValue::isLocalLinkage(), llvm::GlobalValue::isWeakAnyLinkage(), llvm::GlobalValue::isWeakODRLinkage(), LLVM_DEBUG, and Local.

Referenced by llvm::thinLTOPropagateFunctionAttrs().

canReturn()

static bool canReturn ( Function &  F )

static

Definition at line 2052 of file FunctionAttrs.cpp.

References basicBlockCanReturn(), llvm::SmallVectorBase< Size_T >::empty(), F, llvm::SmallPtrSetImpl< PtrType >::insert(), llvm::SmallVectorImpl< T >::pop_back_val(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), and llvm::successors().

Referenced by addNoReturnAttrs().

checkFunctionMemoryAccess()

static std::pair< MemoryEffects, MemoryEffects > checkFunctionMemoryAccess ( Function &  F, bool  ThisBody, AAResults &  AAR, const SCCNodeSet &  SCCNodes  )

static

Returns the memory access attribute for function F using AAR for AA results, where SCCNodes is the current SCC.

If ThisBody is true, this function may examine the function body and will return a result pertaining to this copy of the function. If it is false, the result will be based only on AA results for the function declaration; it will be assumed that some other (perhaps less optimized) version of the function may be selected at link time.

The return value is split into two parts: Memory effects that always apply, and additional memory effects that apply if any of the functions in the SCC can access argmem.

Definition at line 163 of file FunctionAttrs.cpp.

References addArgLocs(), addLocAccess(), llvm::MemoryEffectsBase< LocationEnum >::argMemOnly(), llvm::MemoryEffectsBase< LocationEnum >::doesNotAccessMemory(), F, llvm::AAResults::getMemoryEffects(), llvm::MemoryEffectsBase< LocationEnum >::getModRef(), llvm::MemoryLocation::getOrNone(), llvm::MemoryEffectsBase< LocationEnum >::getWithoutLoc(), I, llvm::MemoryEffectsBase< LocationEnum >::inaccessibleMemOnly(), instructions, and llvm::MemoryEffectsBase< LocationEnum >::none().

Referenced by addMemoryAttrs(), and llvm::computeFunctionBodyMemoryAccess().

createSCCNodeSet()

static SCCNodesResult createSCCNodeSet ( ArrayRef< Function * >  Functions )

static

Definition at line 2193 of file FunctionAttrs.cpp.

References F, llvm::CallBase::getCalledFunction(), I, and instructions.

Referenced by deriveAttrsInPostOrder().

deduceFunctionAttributeInRPO()

static bool deduceFunctionAttributeInRPO ( Module &  M, LazyCallGraph &  CG  )

static

Definition at line 2382 of file FunctionAttrs.cpp.

References addNoRecurseAttrsTopDown(), llvm::LazyCallGraph::buildRefSCCs(), F, llvm::LazyCallGraph::postorder_ref_sccs(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), and llvm::reverse().

Referenced by llvm::ReversePostOrderFunctionAttrsPass::run().

deriveAttrsInPostOrder()

template<typename AARGetterT >

static SmallSet< Function *, 8 > deriveAttrsInPostOrder ( ArrayRef< Function * >  Functions, AARGetterT &&  AARGetter, bool  ArgAttrsOnly  )

static

Definition at line 2225 of file FunctionAttrs.cpp.

References addArgumentAttrs(), addArgumentReturnedAttrs(), addColdAttrs(), addMemoryAttrs(), addNoAliasAttrs(), addNonNullAttrs(), addNoRecurseAttrs(), addNoReturnAttrs(), addNoUndefAttrs(), addWillReturn(), createSCCNodeSet(), F, llvm::inferAttributesFromOthers(), inferAttrsFromFunctionBodies(), inferConvergent(), and llvm::SmallSet< T, N, C >::insert().

Referenced by llvm::PostOrderFunctionAttrsPass::run(), and runImpl().

determinePointerAccessAttrs()

static Attribute::AttrKind determinePointerAccessAttrs ( Argument *  A, const SmallPtrSet< Argument *, 8 > &  SCCNodes  )

static

Returns Attribute::None, Attribute::ReadOnly or Attribute::ReadNone.

Definition at line 810 of file FunctionAttrs.cpp.

References A, llvm::ArgMem, llvm::SmallPtrSetImpl< PtrType >::count(), llvm::CallBase::dataOperandHasImpliedAttr(), llvm::CallBase::doesNotAccessMemory(), llvm::CallBase::doesNotCapture(), llvm::SmallVectorBase< Size_T >::empty(), F, llvm::CallBase::getCalledFunction(), llvm::CallBase::getDataOperandNo(), llvm::CallBase::getMemoryEffects(), llvm::MemoryEffectsBase< LocationEnum >::getModRef(), I, llvm::SmallPtrSetImpl< PtrType >::insert(), llvm::CallBase::isArgOperand(), llvm::CallBase::isCallee(), llvm::isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(), llvm::isModSet(), llvm::isNoModRef(), llvm::isRefSet(), llvm::Attribute::None, llvm::CallBase::onlyReadsMemory(), llvm::SmallVectorImpl< T >::pop_back_val(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), and llvm::Value::uses().

Referenced by addArgumentAttrs().

functionWillReturn()

static bool functionWillReturn ( const Function &  F )

static

Definition at line 2151 of file FunctionAttrs.cpp.

References llvm::all_of(), llvm::SmallVectorBase< Size_T >::empty(), F, llvm::FindFunctionBackedges(), I, and instructions.

Referenced by addWillReturn().

inferAttrsFromFunctionBodies()

static void inferAttrsFromFunctionBodies ( const SCCNodeSet &  SCCNodes, SmallSet< Function *, 8 > &  Changed  )

static

Infer attributes from all functions in the SCC by scanning every instruction for compliance to the attribute assumptions.

Returns true if any changes to function attributes were made.

Definition at line 1933 of file FunctionAttrs.cpp.

References llvm::dbgs(), DisableNoFreeInference, DisableNoUnwindInference, F, I, InstrBreaksNoFree(), InstrBreaksNonThrowing(), InstrBreaksNoSync(), and LLVM_DEBUG.

Referenced by deriveAttrsInPostOrder().

inferConvergent()

static void inferConvergent ( const SCCNodeSet &  SCCNodes, SmallSet< Function *, 8 > &  Changed  )

static

Attempt to remove convergent function attribute when possible.

Returns true if any changes to function attributes were made.

Definition at line 1902 of file FunctionAttrs.cpp.

References llvm::dbgs(), F, I, InstrBreaksNonConvergent(), and LLVM_DEBUG.

Referenced by deriveAttrsInPostOrder().

inferInitializes()

static bool inferInitializes ( Argument &  A, Function &  F  )

static

Definition at line 1068 of file FunctionAttrs.cpp.

References _, A, llvm::append_range(), assert(), llvm::ConstantRangeList::empty(), llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::end(), F, llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::find(), llvm::Attribute::get(), Info, llvm::ConstantRangeList::intersectWith(), LHS, llvm::post_order(), llvm::ConstantRangeList::rangesRef(), llvm::reverse(), RHS, llvm::sort(), llvm::ConstantRangeList::subtract(), llvm::successors(), and llvm::ConstantRangeList::unionWith().

Referenced by addArgumentAttrs().

InstrBreaksNoFree()

static bool InstrBreaksNoFree ( Instruction &  I, const SCCNodeSet &  SCCNodes  )

static

Helper for NoFree inference predicate InstrBreaksAttribute.

Definition at line 1828 of file FunctionAttrs.cpp.

References llvm::CallBase::getCalledFunction(), llvm::CallBase::hasFnAttr(), and I.

Referenced by inferAttrsFromFunctionBodies().

InstrBreaksNonConvergent()

static bool InstrBreaksNonConvergent ( Instruction &  I, const SCCNodeSet &  SCCNodes  )

static

Helper for non-Convergent inference predicate InstrBreaksAttribute.

Definition at line 1802 of file FunctionAttrs.cpp.

References llvm::CallBase::getCalledFunction(), I, and llvm::CallBase::isConvergent().

Referenced by inferConvergent().

InstrBreaksNonThrowing()

static bool InstrBreaksNonThrowing ( Instruction &  I, const SCCNodeSet &  SCCNodes  )

static

Helper for NoUnwind inference predicate InstrBreaksAttribute.

Definition at line 1812 of file FunctionAttrs.cpp.

References I.

Referenced by inferAttrsFromFunctionBodies().

InstrBreaksNoSync()

static bool InstrBreaksNoSync ( Instruction &  I, const SCCNodeSet &  SCCNodes  )

static

Definition at line 1867 of file FunctionAttrs.cpp.

References llvm::CallBase::getCalledFunction(), llvm::CallBase::hasFnAttr(), I, isOrderedAtomic(), and MI.

Referenced by inferAttrsFromFunctionBodies().

instructionDoesNotReturn()

static bool instructionDoesNotReturn ( Instruction &  I )

static

Definition at line 2037 of file FunctionAttrs.cpp.

References llvm::CallBase::hasFnAttr(), and I.

Referenced by basicBlockCanReturn().

isFunctionMallocLike()

static bool isFunctionMallocLike ( Function *  F, const SCCNodeSet &  SCCNodes  )

static

Tests whether a function is "malloc-like".

A function is "malloc-like" if it returns either null or a pointer that doesn't alias any other pointer visible to the caller.

Definition at line 1378 of file FunctionAttrs.cpp.

References llvm::CallingConv::C, F, llvm::CallBase::getCalledFunction(), llvm::CallBase::hasRetAttr(), llvm::PHINode::incoming_values(), llvm::SetVector< T, Vector, Set, N >::insert(), llvm::PointerMayBeCaptured(), and llvm::SetVector< T, Vector, Set, N >::size().

Referenced by addNoAliasAttrs().

isOrderedAtomic()

static bool isOrderedAtomic ( Instruction *  I )

static

Definition at line 1849 of file FunctionAttrs.cpp.

References I, llvm_unreachable, and llvm::SyncScope::SingleThread.

Referenced by InstrBreaksNoSync().

isReturnNonNull()

static bool isReturnNonNull ( Function *  F, const SCCNodeSet &  SCCNodes, bool &  Speculative  )

static

Tests whether this function is known to not return null.

Requires that the function returns a pointer.

Returns true if it believes the function will not return a null, and sets Speculative based on whether the returned conclusion is a speculative conclusion due to SCC calls.

Definition at line 1484 of file FunctionAttrs.cpp.

References assert(), DL, F, llvm::CallBase::getCalledFunction(), llvm::PHINode::getIncomingValue(), llvm::PHINode::getNumIncomingValues(), llvm::Instruction::getOpcode(), llvm::User::getOperand(), llvm::SetVector< T, Vector, Set, N >::insert(), llvm::isKnownNonZero(), llvm_unreachable, and llvm::SetVector< T, Vector, Set, N >::size().

Referenced by addNonNullAttrs().

runImpl()

template<typename AARGetterT >

static bool runImpl ( CallGraphSCC &  SCC, AARGetterT  AARGetter  )

static

Definition at line 2341 of file FunctionAttrs.cpp.

References deriveAttrsInPostOrder(), I, and llvm::SmallVectorTemplateBase< T, bool >::push_back().

STATISTIC() [1/17]

STATISTIC	(	NumCold	,
		"Number of functions marked as cold"
	)

STATISTIC() [2/17]

STATISTIC	(	NumMemoryAttr	,
		"Number of functions with improved memory attribute"
	)

STATISTIC() [3/17]

STATISTIC	(	NumNoAlias	,
		"Number of function returns marked noalias"
	)

STATISTIC() [4/17]

STATISTIC	(	NumNoCapture	,
		"Number of arguments marked nocapture"
	)

STATISTIC() [5/17]

STATISTIC	(	NumNoFree	,
		"Number of functions marked as nofree"
	)

STATISTIC() [6/17]

STATISTIC	(	NumNonNullReturn	,
		"Number of function returns marked nonnull"
	)

STATISTIC() [7/17]

STATISTIC	(	NumNoRecurse	,
		"Number of functions marked as norecurse"
	)

STATISTIC() [8/17]

STATISTIC	(	NumNoSync	,
		"Number of functions marked as nosync"
	)

STATISTIC() [9/17]

STATISTIC	(	NumNoUndefReturn	,
		"Number of function returns marked noundef"
	)

STATISTIC() [10/17]

STATISTIC	(	NumNoUnwind	,
		"Number of functions marked as nounwind"
	)

STATISTIC() [11/17]

STATISTIC	(	NumReadNoneArg	,
		"Number of arguments marked readnone"
	)

STATISTIC() [12/17]

STATISTIC	(	NumReadOnlyArg	,
		"Number of arguments marked readonly"
	)

STATISTIC() [13/17]

STATISTIC	(	NumReturned	,
		"Number of arguments marked returned"
	)

STATISTIC() [14/17]

STATISTIC	(	NumThinLinkNoRecurse	,
		"Number of functions marked as norecurse during thinlink"
	)

STATISTIC() [15/17]

STATISTIC	(	NumThinLinkNoUnwind	,
		"Number of functions marked as nounwind during thinlink"
	)

STATISTIC() [16/17]

STATISTIC	(	NumWillReturn	,
		"Number of functions marked as willreturn"
	)

STATISTIC() [17/17]

STATISTIC	(	NumWriteOnlyArg	,
		"Number of arguments marked writeonly"
	)

Variable Documentation

DisableNoFreeInference

cl::opt< bool > DisableNoFreeInference("disable-nofree-inference", cl::Hidden, cl::desc("Stop inferring nofree attribute during function-attrs pass")) ( "disable-nofree-inference"  , cl::Hidden  , cl::desc("Stop inferring nofree attribute during function-attrs pass")    )

static

Referenced by inferAttrsFromFunctionBodies().

DisableNoUnwindInference

cl::opt< bool > DisableNoUnwindInference("disable-nounwind-inference", cl::Hidden, cl::desc("Stop inferring nounwind attribute during function-attrs pass")) ( "disable-nounwind-inference"  , cl::Hidden  , cl::desc("Stop inferring nounwind attribute during function-attrs pass")    )

static

Referenced by inferAttrsFromFunctionBodies().

DisableThinLTOPropagation

cl::opt< bool > DisableThinLTOPropagation("disable-thinlto-funcattrs", cl::init(true), cl::Hidden, cl::desc("Don't propagate function-attrs in thinLTO")) ( "disable-thinlto-funcattrs"  , cl::init(true)  , cl::Hidden  , cl::desc("Don't propagate function-attrs in thinLTO")    )

static

Referenced by llvm::thinLTOPropagateFunctionAttrs().

EnableNonnullArgPropagation

cl::opt< bool > EnableNonnullArgPropagation("enable-nonnull-arg-prop", cl::init(true), cl::Hidden, cl::desc("Try to propagate nonnull argument attributes from callsites to " "caller functions.")) ( "enable-nonnull-arg-prop"  , cl::init(true)  , cl::Hidden  , cl::desc("Try to propagate nonnull argument attributes from callsites to " "caller functions.")    )

static

Referenced by addArgumentAttrsFromCallsites().