LLVM  4.0.0
Macros | Functions | Variables
BasicAliasAnalysis.cpp File Reference
#include "llvm/Analysis/BasicAliasAnalysis.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/CaptureTracking.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/MemoryBuiltins.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Operator.h"
#include "llvm/Pass.h"
#include "llvm/Support/ErrorHandling.h"
#include <algorithm>
Include dependency graph for BasicAliasAnalysis.cpp:

Go to the source code of this file.

Macros

#define DEBUG_TYPE   "basicaa"
 

Functions

 STATISTIC (SearchLimitReached,"Number of times the limit to ""decompose GEPs is reached")
 SearchLimitReached / SearchTimes shows how often the limit of to decompose GEPs is reached. More...
 
 STATISTIC (SearchTimes,"Number of times a GEP is decomposed")
 
static bool isNonEscapingLocalObject (const Value *V)
 Returns true if the pointer is to a function-local object that never escapes from the function. More...
 
static bool isEscapeSource (const Value *V)
 Returns true if the pointer is one which would have been considered an escape by isNonEscapingLocalObject. More...
 
static uint64_t getObjectSize (const Value *V, const DataLayout &DL, const TargetLibraryInfo &TLI, bool RoundToAlign=false)
 Returns the size of the object specified by V or UnknownSize if unknown. More...
 
static bool isObjectSmallerThan (const Value *V, uint64_t Size, const DataLayout &DL, const TargetLibraryInfo &TLI)
 Returns true if we can prove that the object specified by V is smaller than Size. More...
 
static bool isObjectSize (const Value *V, uint64_t Size, const DataLayout &DL, const TargetLibraryInfo &TLI)
 Returns true if we can prove that the object specified by V has size Size. More...
 
static int64_t adjustToPointerSize (int64_t Offset, unsigned PointerSize)
 To ensure a pointer offset fits in an integer of size PointerSize (in bits) when that size is smaller than 64. More...
 
static bool isWriteOnlyParam (ImmutableCallSite CS, unsigned ArgIdx, const TargetLibraryInfo &TLI)
 Returns true if this is a writeonly (i.e Mod only) parameter. More...
 
static bool isIntrinsicCall (ImmutableCallSite CS, Intrinsic::ID IID)
 
static const FunctiongetParent (const Value *V)
 
static bool notDifferentParent (const Value *O1, const Value *O2)
 
static AliasResult aliasSameBasePointerGEPs (const GEPOperator *GEP1, uint64_t V1Size, const GEPOperator *GEP2, uint64_t V2Size, const DataLayout &DL)
 Provide ad-hoc rules to disambiguate accesses through two GEP operators, both having the exact same pointer operand. More...
 
static AliasResult MergeAliasResults (AliasResult A, AliasResult B)
 
 INITIALIZE_PASS_BEGIN (BasicAAWrapperPass,"basicaa","Basic Alias Analysis (stateless AA impl)", true, true) INITIALIZE_PASS_END(BasicAAWrapperPass
 
Basic Alias Analysis (stateless AA impl)"
 

Variables

static cl::opt< boolEnableRecPhiAnalysis ("basicaa-recphi", cl::Hidden, cl::init(false))
 Enable analysis of recursive PHI nodes. More...
 
const unsigned MaxNumPhiBBsValueReachabilityCheck = 20
 Cutoff after which to stop analysing a set of phi nodes potentially involved in a cycle. More...
 
static const unsigned MaxLookupSearchDepth = 6
 
 basicaa
 
Basic Alias true
 

Macro Definition Documentation

#define DEBUG_TYPE   "basicaa"

Definition at line 41 of file BasicAliasAnalysis.cpp.

Function Documentation

static int64_t adjustToPointerSize ( int64_t  Offset,
unsigned  PointerSize 
)
static

To ensure a pointer offset fits in an integer of size PointerSize (in bits) when that size is smaller than 64.

This is an issue in particular for 32b programs with negative indices that rely on two's complement wrap-arounds for precise alias information.

Definition at line 342 of file BasicAliasAnalysis.cpp.

References assert().

static AliasResult aliasSameBasePointerGEPs ( const GEPOperator GEP1,
uint64_t  V1Size,
const GEPOperator GEP2,
uint64_t  V2Size,
const DataLayout DL 
)
static
Basic Alias Analysis ( stateless AA  impl)
static uint64_t getObjectSize ( const Value V,
const DataLayout DL,
const TargetLibraryInfo TLI,
bool  RoundToAlign = false 
)
static

Returns the size of the object specified by V or UnknownSize if unknown.

Definition at line 126 of file BasicAliasAnalysis.cpp.

References llvm::getObjectSize(), and llvm::MemoryLocation::UnknownSize.

static const Function* getParent ( const Value V)
static
INITIALIZE_PASS_BEGIN ( BasicAAWrapperPass  ,
"basicaa"  ,
"Basic Alias Analysis (stateless AA impl)"  ,
true  ,
true   
)
static bool isEscapeSource ( const Value V)
static

Returns true if the pointer is one which would have been considered an escape by isNonEscapingLocalObject.

Definition at line 112 of file BasicAliasAnalysis.cpp.

static bool isIntrinsicCall ( ImmutableCallSite  CS,
Intrinsic::ID  IID 
)
static
static bool isNonEscapingLocalObject ( const Value V)
static

Returns true if the pointer is to a function-local object that never escapes from the function.

Definition at line 87 of file BasicAliasAnalysis.cpp.

References A, llvm::isNoAliasCall(), and llvm::PointerMayBeCaptured().

Referenced by llvm::BasicAAResult::getModRefInfo().

static bool isObjectSize ( const Value V,
uint64_t  Size,
const DataLayout DL,
const TargetLibraryInfo TLI 
)
static

Returns true if we can prove that the object specified by V has size Size.

Definition at line 177 of file BasicAliasAnalysis.cpp.

References llvm::getObjectSize(), and llvm::MemoryLocation::UnknownSize.

static bool isObjectSmallerThan ( const Value V,
uint64_t  Size,
const DataLayout DL,
const TargetLibraryInfo TLI 
)
static

Returns true if we can prove that the object specified by V is smaller than Size.

Definition at line 137 of file BasicAliasAnalysis.cpp.

References llvm::getObjectSize(), llvm::isIdentifiedObject(), and llvm::MemoryLocation::UnknownSize.

static bool isWriteOnlyParam ( ImmutableCallSite  CS,
unsigned  ArgIdx,
const TargetLibraryInfo TLI 
)
static
static AliasResult MergeAliasResults ( AliasResult  A,
AliasResult  B 
)
static

Definition at line 1315 of file BasicAliasAnalysis.cpp.

References A, llvm::MayAlias, llvm::MustAlias, and llvm::PartialAlias.

static bool notDifferentParent ( const Value O1,
const Value O2 
)
static
STATISTIC ( SearchLimitReached  ,
"Number of times the limit to ""decompose GEPs is reached"   
)

SearchLimitReached / SearchTimes shows how often the limit of to decompose GEPs is reached.

It will affect the precision of basic alias analysis.

STATISTIC ( SearchTimes  ,
"Number of times a GEP is decomposed"   
)

Variable Documentation

basicaa

Definition at line 1781 of file BasicAliasAnalysis.cpp.

cl::opt<bool> EnableRecPhiAnalysis("basicaa-recphi", cl::Hidden, cl::init(false))
static

Enable analysis of recursive PHI nodes.

const unsigned MaxLookupSearchDepth = 6
static

Definition at line 64 of file BasicAliasAnalysis.cpp.

const unsigned MaxNumPhiBBsValueReachabilityCheck = 20

Cutoff after which to stop analysing a set of phi nodes potentially involved in a cycle.

Because we are analysing 'through' phi nodes, we need to be careful with value equivalence. We use reachability to make sure a value cannot be involved in a cycle.

Definition at line 59 of file BasicAliasAnalysis.cpp.

dot regions Print regions of function to dot true view regions View regions of true

Definition at line 1782 of file BasicAliasAnalysis.cpp.