MemorySSA.cpp File Reference

#include "llvm/Analysis/MemorySSA.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/ADT/iterator.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/CFGPrinter.h"
#include "llvm/Analysis/IteratedDominanceFrontier.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/MemoryLocation.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/IR/AssemblyAnnotationWriter.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/Use.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/AtomicOrdering.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/FormattedStream.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <iterator>
#include <memory>
#include <utility>

Go to the source code of this file.

Classes
struct	llvm::DenseMapInfo< MemoryLocOrCall >
class	llvm::MemorySSA::ClobberWalkerBase
class	llvm::MemorySSA::CachingWalker
	A MemorySSAWalker that does AA walks to disambiguate accesses. More...
class	llvm::MemorySSA::SkipSelfWalker
class	llvm::MemorySSA::OptimizeUses
	This class is a batch walker of all MemoryUse's in the program, and points their defining access at the thing that actually clobbers them. More...
class	DOTFuncMSSAInfo
struct	llvm::GraphTraits< DOTFuncMSSAInfo * >
struct	llvm::DOTGraphTraits< DOTFuncMSSAInfo * >

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

Macros
#define	DEBUG_TYPE   "memoryssa"

Functions
	INITIALIZE_PASS_BEGIN (MemorySSAWrapperPass, "memoryssa", "Memory SSA", false, true) INITIALIZE_PASS_END(MemorySSAWrapperPass
Memory static true cl::opt< unsigned >	MaxCheckLimit ("memssa-check-limit", cl::Hidden, cl::init(100), cl::desc("The maximum number of stores/phis MemorySSA" "will consider trying to walk past (default = 100)"))
static bool	areLoadsReorderable (const LoadInst *Use, const LoadInst *MayClobber)
	This does one-way checks to see if Use could theoretically be hoisted above MayClobber.
template<typename AliasAnalysisType >
static bool	instructionClobbersQuery (const MemoryDef *MD, const MemoryLocation &UseLoc, const Instruction *UseInst, AliasAnalysisType &AA)
template<typename AliasAnalysisType >
static bool	instructionClobbersQuery (MemoryDef *MD, const MemoryUseOrDef *MU, const MemoryLocOrCall &UseMLOC, AliasAnalysisType &AA)
template<typename AliasAnalysisType >
static bool	isUseTriviallyOptimizableToLiveOnEntry (AliasAnalysisType &AA, const Instruction *I)
static LLVM_ATTRIBUTE_UNUSED void	checkClobberSanity (const MemoryAccess *Start, MemoryAccess *ClobberAt, const MemoryLocation &StartLoc, const MemorySSA &MSSA, const UpwardsMemoryQuery &Query, BatchAAResults &AA, bool AllowImpreciseClobber=false)
	Verifies that Start is clobbered by ClobberAt, and that nothing inbetween Start and ClobberAt can clobbers Start.
static bool	isOrdered (const Instruction *I)
static const Instruction *	getInvariantGroupClobberingInstruction (Instruction &I, DominatorTree &DT)

Variables
static cl::opt< std::string >	DotCFGMSSA ("dot-cfg-mssa", cl::value_desc("file name for generated dot file"), cl::desc("file name for generated dot file"), cl::init(""))
	memoryssa
Memory	SSA
Memory	false
static cl::opt< bool, true >	VerifyMemorySSAX ("verify-memoryssa", cl::location(VerifyMemorySSA), cl::Hidden, cl::desc("Enable verification of MemorySSA."))
static const char	LiveOnEntryStr [] = "liveOnEntry"

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "memoryssa"

Definition at line 61 of file MemorySSA.cpp.

Function Documentation

areLoadsReorderable()

static bool areLoadsReorderable ( const LoadInst *  Use, const LoadInst *  MayClobber  )

static

This does one-way checks to see if Use could theoretically be hoisted above MayClobber.

This will not check the other way around.

This assumes that, for the purposes of MemorySSA, Use comes directly after MayClobber, with no potentially clobbering operations in between them. (Where potentially clobbering ops are memory barriers, aliased stores, etc.)

Definition at line 256 of file MemorySSA.cpp.

References llvm::LoadInst::getOrdering(), llvm::isAtLeastOrStrongerThan(), and llvm::LoadInst::isVolatile().

Referenced by instructionClobbersQuery().

checkClobberSanity()

static LLVM_ATTRIBUTE_UNUSED void checkClobberSanity ( const MemoryAccess *  Start, MemoryAccess *  ClobberAt, const MemoryLocation &  StartLoc, const MemorySSA &  MSSA, const UpwardsMemoryQuery &  Query, BatchAAResults &  AA, bool  AllowImpreciseClobber = false  )

static

Verifies that Start is clobbered by ClobberAt, and that nothing inbetween Start and ClobberAt can clobbers Start.

This is meant to be as simple and self-contained as possible. Because it uses no cache, etc., it can be relatively expensive.

Parameters

Start	The MemoryAccess that we want to walk from.
ClobberAt	A clobber for Start.
StartLoc	The MemoryLocation for Start.
MSSA	The MemorySSA instance that Start and ClobberAt belong to.
Query	The UpwardsMemoryQuery we used for our search.
AA	The AliasAnalysis we used for our search.
AllowImpreciseClobber	Always false, unless we do relaxed verify.

Definition at line 397 of file MemorySSA.cpp.

References assert(), llvm::def_chain(), llvm::MemorySSA::dominates(), llvm::SmallVectorImpl< T >::emplace_back(), llvm::SmallVectorBase< Size_T >::empty(), llvm::MemorySSA::getDomTree(), llvm::detail::DenseSetImpl< ValueT, MapTy, ValueInfoT >::insert(), instructionClobbersQuery(), llvm::MemorySSA::isLiveOnEntryDef(), llvm::DominatorTree::isReachableFromEntry(), MAP, llvm::SmallVectorImpl< T >::pop_back_val(), llvm::upward_defs_begin(), and llvm::upward_defs_end().

getInvariantGroupClobberingInstruction()

static const Instruction * getInvariantGroupClobberingInstruction ( Instruction &  I, DominatorTree &  DT  )

static

Definition at line 2494 of file MemorySSA.cpp.

References llvm::DominatorTree::dominates(), llvm::getLoadStorePointerOperand(), I, llvm::Value::stripPointerCasts(), and llvm::Value::users().

Referenced by llvm::MemorySSA::ClobberWalkerBase::getClobberingMemoryAccessBase().

INITIALIZE_PASS_BEGIN()

INITIALIZE_PASS_BEGIN	(	MemorySSAWrapperPass	,
		"memoryssa"	,
		"Memory SSA"	,
		false	,
		true
	)

instructionClobbersQuery() [1/2]

template<typename AliasAnalysisType >

static bool instructionClobbersQuery ( const MemoryDef *  MD, const MemoryLocation &  UseLoc, const Instruction *  UseInst, AliasAnalysisType &  AA  )

static

Definition at line 282 of file MemorySSA.cpp.

References areLoadsReorderable(), assert(), llvm::MemoryUseOrDef::getMemoryInst(), I, II, llvm::isModOrRefSet(), llvm::isModSet(), and llvm_unreachable.

Referenced by checkClobberSanity(), llvm::MemorySSAUtil::defClobbersUseOrDef(), and instructionClobbersQuery().

instructionClobbersQuery() [2/2]

template<typename AliasAnalysisType >

static bool instructionClobbersQuery ( MemoryDef *  MD, const MemoryUseOrDef *  MU, const MemoryLocOrCall &  UseMLOC, AliasAnalysisType &  AA  )

static

Definition at line 327 of file MemorySSA.cpp.

References llvm::MemoryUseOrDef::getMemoryInst(), and instructionClobbersQuery().

isOrdered()

static bool isOrdered ( const Instruction *  I )

inlinestatic

Definition at line 1745 of file MemorySSA.cpp.

References I.

Referenced by llvm::MemoryDependenceResults::getNonLocalPointerDependency().

isUseTriviallyOptimizableToLiveOnEntry()

template<typename AliasAnalysisType >

static bool isUseTriviallyOptimizableToLiveOnEntry ( AliasAnalysisType &  AA, const Instruction *  I  )

static

Definition at line 371 of file MemorySSA.cpp.

References llvm::MemoryLocation::get(), I, and llvm::isModSet().

Referenced by llvm::MemorySSA::ClobberWalkerBase::getClobberingMemoryAccessBase().

MaxCheckLimit()

Memory static true cl::opt< unsigned > MaxCheckLimit ( "memssa-check-limit"  , cl::Hidden  , cl::init(100)  , cl::desc("The maximum number of stores/phis MemorySSA" "will consider trying to walk past (default = 100)")    )

static

Referenced by llvm::MemorySSA::CachingWalker::getClobberingMemoryAccess(), and llvm::MemorySSA::SkipSelfWalker::getClobberingMemoryAccess().

Variable Documentation

DotCFGMSSA

cl::opt< std::string > DotCFGMSSA("dot-cfg-mssa", cl::value_desc("file name for generated dot file"), cl::desc("file name for generated dot file"), cl::init("")) ( "dot-cfg-mssa"  , cl::value_desc("file name for generated dot file")  , cl::desc("file name for generated dot file")  , cl::init("")    )

static

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

false

Memory false

Definition at line 72 of file MemorySSA.cpp.

LiveOnEntryStr

const char LiveOnEntryStr[] = "liveOnEntry"

static

Definition at line 91 of file MemorySSA.cpp.

Referenced by llvm::MemoryUse::print(), llvm::MemoryDef::print(), and llvm::MemoryPhi::print().

memoryssa

memoryssa

Definition at line 72 of file MemorySSA.cpp.

SSA

Memory SSA

Definition at line 72 of file MemorySSA.cpp.

Referenced by llvm::promoteLoopAccessesToScalars(), and RewriteUsesOfClonedInstructions().

VerifyMemorySSAX

cl::opt< bool, true > VerifyMemorySSAX("verify-memoryssa", cl::location(VerifyMemorySSA), cl::Hidden, cl::desc("Enable verification of MemorySSA.")) ( "verify-memoryssa"  , cl::location(VerifyMemorySSA)  , cl::Hidden  , cl::desc("Enable verification of MemorySSA.")    )

static