LLVM: lib/Transforms/IPO/FunctionAttrs.cpp File Reference (original) (raw)

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

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

Definition in file FunctionAttrs.cpp.

◆ DEBUG_TYPE

#define DEBUG_TYPE "function-attrs"

◆ addAccessAttr()

◆ addArgLocs()

◆ addArgumentAttrs()

Deduce nocapture attributes for the SCC.

Definition at line 1239 of file FunctionAttrs.cpp.

References A(), addAccessAttr(), addArgumentAttrsFromCallsites(), addCapturesStat(), B(), llvm::capturesAll(), llvm::capturesAnyProvenance(), llvm::capturesNothing(), Changed, llvm::SmallPtrSetImpl< PtrType >::count(), determinePointerAccessAttrs(), F, llvm::Attribute::getWithCaptureInfo(), I, inferInitializes(), llvm::SmallPtrSetImpl< PtrType >::insert(), N, llvm::Attribute::None, llvm::None, llvm::CaptureInfo::none(), llvm::PointerMayBeCaptured(), llvm::scc_begin(), and Uses.

Referenced by deriveAttrsInPostOrder().

◆ addArgumentAttrsFromCallsites()

◆ addArgumentReturnedAttrs()

◆ addCapturesStat()

◆ addColdAttrs()

◆ addLocAccess()

◆ addMemoryAttrs()

template

◆ addNoAliasAttrs()

◆ addNonNullAttrs()

◆ addNoRecurseAttrs()

◆ addNoRecurseAttrsTopDown()

◆ addNoReturnAttrs()

◆ addNoUndefAttrs()

Deduce noundef attributes for the SCC.

Definition at line 1681 of file FunctionAttrs.cpp.

References llvm::all_of(), Changed, llvm::computeConstantRange(), llvm::ConstantRange::contains(), DL, llvm::dyn_cast(), F, llvm::Value::getPointerAlignment(), llvm::Attribute::getRange(), llvm::BasicBlock::getTerminator(), llvm::isGuaranteedNotToBeUndefOrPoison(), llvm::isKnownNonZero(), and llvm::Attribute::isValid().

Referenced by deriveAttrsInPostOrder().

◆ addWillReturn()

◆ allPathsGoThroughCold()

Definition at line 2136 of file FunctionAttrs.cpp.

References llvm::any_of(), llvm::dyn_cast(), llvm::SmallVectorTemplateCommon< T, typename >::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().

◆ calculatePrevailingSummary()

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 315 of file FunctionAttrs.cpp.

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

Referenced by llvm::thinLTOPropagateFunctionAttrs().

◆ checkFunctionMemoryAccess()

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 172 of file FunctionAttrs.cpp.

References addArgLocs(), addLocAccess(), llvm::ArgMem, llvm::MemoryEffectsBase< IRMemLocation >::argMemOnly(), Call, llvm::MemoryEffectsBase< LocationEnum >::doesNotAccessMemory(), llvm::dyn_cast(), F, llvm::AAResults::getMemoryEffects(), llvm::MemoryEffectsBase< LocationEnum >::getModRef(), llvm::MemoryLocation::getOrNone(), llvm::MemoryEffectsBase< LocationEnum >::getWithoutLoc(), I, llvm::MemoryEffectsBase< IRMemLocation >::inaccessibleMemOnly(), instructions, llvm::isa(), llvm::Mod, llvm::ModRef, llvm::NoModRef, llvm::MemoryEffectsBase< IRMemLocation >::none(), llvm::Other, and llvm::Ref.

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

◆ createSCCNodeSet()

◆ deduceFunctionAttributeInRPO()

◆ deriveAttrsInPostOrder()

template

Definition at line 2258 of file FunctionAttrs.cpp.

References addArgumentAttrs(), addArgumentReturnedAttrs(), addColdAttrs(), addMemoryAttrs(), addNoAliasAttrs(), addNonNullAttrs(), addNoRecurseAttrs(), addNoReturnAttrs(), addNoUndefAttrs(), addWillReturn(), Changed, createSCCNodeSet(), F, llvm::inferAttributesFromOthers(), inferAttrsFromFunctionBodies(), and inferConvergent().

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

◆ determinePointerAccessAttrs()

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

Definition at line 861 of file FunctionAttrs.cpp.

References A(), llvm::ArgMem, llvm::capturesAnyProvenance(), llvm::cast(), llvm::SmallPtrSetImpl< PtrType >::count(), llvm::CallBase::dataOperandHasImpliedAttr(), llvm::CallBase::doesNotAccessMemory(), llvm::SmallVectorTemplateCommon< T, typename >::empty(), F, llvm::CallBase::getCalledFunction(), llvm::CallBase::getCaptureInfo(), 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()

◆ inferAttrsFromFunctionBodies()

◆ inferConvergent()

◆ inferInitializes()

Definition at line 1119 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()

◆ InstrBreaksNonConvergent()

◆ InstrBreaksNonThrowing()

◆ InstrBreaksNoSync()

◆ isFunctionMallocLike()

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 1448 of file FunctionAttrs.cpp.

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

Referenced by addNoAliasAttrs().

◆ isOrderedAtomic()

◆ isReturnNonNull()

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 1553 of file FunctionAttrs.cpp.

References assert(), llvm::cast(), DL, llvm::dyn_cast(), 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().

◆ mayHaveRecursiveCallee()

◆ runImpl()

template

◆ STATISTIC() [1/18]

◆ STATISTIC() [2/18]

◆ STATISTIC() [3/18]

◆ STATISTIC() [4/18]

◆ STATISTIC() [5/18]

◆ STATISTIC() [6/18]

◆ STATISTIC() [7/18]

◆ STATISTIC() [8/18]

◆ STATISTIC() [9/18]

◆ STATISTIC() [10/18]

◆ STATISTIC() [11/18]

◆ STATISTIC() [12/18]

◆ STATISTIC() [13/18]

◆ STATISTIC() [14/18]

◆ STATISTIC() [15/18]

◆ STATISTIC() [16/18]

◆ STATISTIC() [17/18]

◆ STATISTIC() [18/18]

◆ DisableNoFreeInference

◆ DisableNoUnwindInference

◆ DisableThinLTOPropagation

◆ EnableNonnullArgPropagation