llvm-6502/lib/Analysis/AliasSetTracker.cpp
Chandler Carruth d04a8d4b33 Use the new script to sort the includes of every file under lib.
Sooooo many of these had incorrect or strange main module includes.
I have manually inspected all of these, and fixed the main module
include to be the nearest plausible thing I could find. If you own or
care about any of these source files, I encourage you to take some time
and check that these edits were sensible. I can't have broken anything
(I strictly added headers, and reordered them, never removed), but they
may not be the headers you'd really like to identify as containing the
API being implemented.

Many forward declarations and missing includes were added to a header
files to allow them to parse cleanly when included first. The main
module rule does in fact have its merits. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169131 91177308-0d34-0410-b5e6-96231b3b80d8
2012-12-03 16:50:05 +00:00

656 lines
22 KiB
C++

//===- AliasSetTracker.cpp - Alias Sets Tracker implementation-------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements the AliasSetTracker and AliasSet classes.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/AliasSetTracker.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/DataLayout.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/LLVMContext.h"
#include "llvm/Pass.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/InstIterator.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Type.h"
using namespace llvm;
/// mergeSetIn - Merge the specified alias set into this alias set.
///
void AliasSet::mergeSetIn(AliasSet &AS, AliasSetTracker &AST) {
assert(!AS.Forward && "Alias set is already forwarding!");
assert(!Forward && "This set is a forwarding set!!");
// Update the alias and access types of this set...
AccessTy |= AS.AccessTy;
AliasTy |= AS.AliasTy;
Volatile |= AS.Volatile;
if (AliasTy == MustAlias) {
// Check that these two merged sets really are must aliases. Since both
// used to be must-alias sets, we can just check any pointer from each set
// for aliasing.
AliasAnalysis &AA = AST.getAliasAnalysis();
PointerRec *L = getSomePointer();
PointerRec *R = AS.getSomePointer();
// If the pointers are not a must-alias pair, this set becomes a may alias.
if (AA.alias(AliasAnalysis::Location(L->getValue(),
L->getSize(),
L->getTBAAInfo()),
AliasAnalysis::Location(R->getValue(),
R->getSize(),
R->getTBAAInfo()))
!= AliasAnalysis::MustAlias)
AliasTy = MayAlias;
}
if (UnknownInsts.empty()) { // Merge call sites...
if (!AS.UnknownInsts.empty())
std::swap(UnknownInsts, AS.UnknownInsts);
} else if (!AS.UnknownInsts.empty()) {
UnknownInsts.insert(UnknownInsts.end(), AS.UnknownInsts.begin(), AS.UnknownInsts.end());
AS.UnknownInsts.clear();
}
AS.Forward = this; // Forward across AS now...
addRef(); // AS is now pointing to us...
// Merge the list of constituent pointers...
if (AS.PtrList) {
*PtrListEnd = AS.PtrList;
AS.PtrList->setPrevInList(PtrListEnd);
PtrListEnd = AS.PtrListEnd;
AS.PtrList = 0;
AS.PtrListEnd = &AS.PtrList;
assert(*AS.PtrListEnd == 0 && "End of list is not null?");
}
}
void AliasSetTracker::removeAliasSet(AliasSet *AS) {
if (AliasSet *Fwd = AS->Forward) {
Fwd->dropRef(*this);
AS->Forward = 0;
}
AliasSets.erase(AS);
}
void AliasSet::removeFromTracker(AliasSetTracker &AST) {
assert(RefCount == 0 && "Cannot remove non-dead alias set from tracker!");
AST.removeAliasSet(this);
}
void AliasSet::addPointer(AliasSetTracker &AST, PointerRec &Entry,
uint64_t Size, const MDNode *TBAAInfo,
bool KnownMustAlias) {
assert(!Entry.hasAliasSet() && "Entry already in set!");
// Check to see if we have to downgrade to _may_ alias.
if (isMustAlias() && !KnownMustAlias)
if (PointerRec *P = getSomePointer()) {
AliasAnalysis &AA = AST.getAliasAnalysis();
AliasAnalysis::AliasResult Result =
AA.alias(AliasAnalysis::Location(P->getValue(), P->getSize(),
P->getTBAAInfo()),
AliasAnalysis::Location(Entry.getValue(), Size, TBAAInfo));
if (Result != AliasAnalysis::MustAlias)
AliasTy = MayAlias;
else // First entry of must alias must have maximum size!
P->updateSizeAndTBAAInfo(Size, TBAAInfo);
assert(Result != AliasAnalysis::NoAlias && "Cannot be part of must set!");
}
Entry.setAliasSet(this);
Entry.updateSizeAndTBAAInfo(Size, TBAAInfo);
// Add it to the end of the list...
assert(*PtrListEnd == 0 && "End of list is not null?");
*PtrListEnd = &Entry;
PtrListEnd = Entry.setPrevInList(PtrListEnd);
assert(*PtrListEnd == 0 && "End of list is not null?");
addRef(); // Entry points to alias set.
}
void AliasSet::addUnknownInst(Instruction *I, AliasAnalysis &AA) {
UnknownInsts.push_back(I);
if (!I->mayWriteToMemory()) {
AliasTy = MayAlias;
AccessTy |= Refs;
return;
}
// FIXME: This should use mod/ref information to make this not suck so bad
AliasTy = MayAlias;
AccessTy = ModRef;
}
/// aliasesPointer - Return true if the specified pointer "may" (or must)
/// alias one of the members in the set.
///
bool AliasSet::aliasesPointer(const Value *Ptr, uint64_t Size,
const MDNode *TBAAInfo,
AliasAnalysis &AA) const {
if (AliasTy == MustAlias) {
assert(UnknownInsts.empty() && "Illegal must alias set!");
// If this is a set of MustAliases, only check to see if the pointer aliases
// SOME value in the set.
PointerRec *SomePtr = getSomePointer();
assert(SomePtr && "Empty must-alias set??");
return AA.alias(AliasAnalysis::Location(SomePtr->getValue(),
SomePtr->getSize(),
SomePtr->getTBAAInfo()),
AliasAnalysis::Location(Ptr, Size, TBAAInfo));
}
// If this is a may-alias set, we have to check all of the pointers in the set
// to be sure it doesn't alias the set...
for (iterator I = begin(), E = end(); I != E; ++I)
if (AA.alias(AliasAnalysis::Location(Ptr, Size, TBAAInfo),
AliasAnalysis::Location(I.getPointer(), I.getSize(),
I.getTBAAInfo())))
return true;
// Check the unknown instructions...
if (!UnknownInsts.empty()) {
for (unsigned i = 0, e = UnknownInsts.size(); i != e; ++i)
if (AA.getModRefInfo(UnknownInsts[i],
AliasAnalysis::Location(Ptr, Size, TBAAInfo)) !=
AliasAnalysis::NoModRef)
return true;
}
return false;
}
bool AliasSet::aliasesUnknownInst(Instruction *Inst, AliasAnalysis &AA) const {
if (!Inst->mayReadOrWriteMemory())
return false;
for (unsigned i = 0, e = UnknownInsts.size(); i != e; ++i) {
CallSite C1 = getUnknownInst(i), C2 = Inst;
if (!C1 || !C2 ||
AA.getModRefInfo(C1, C2) != AliasAnalysis::NoModRef ||
AA.getModRefInfo(C2, C1) != AliasAnalysis::NoModRef)
return true;
}
for (iterator I = begin(), E = end(); I != E; ++I)
if (AA.getModRefInfo(Inst, AliasAnalysis::Location(I.getPointer(),
I.getSize(),
I.getTBAAInfo())) !=
AliasAnalysis::NoModRef)
return true;
return false;
}
void AliasSetTracker::clear() {
// Delete all the PointerRec entries.
for (PointerMapType::iterator I = PointerMap.begin(), E = PointerMap.end();
I != E; ++I)
I->second->eraseFromList();
PointerMap.clear();
// The alias sets should all be clear now.
AliasSets.clear();
}
/// findAliasSetForPointer - Given a pointer, find the one alias set to put the
/// instruction referring to the pointer into. If there are multiple alias sets
/// that may alias the pointer, merge them together and return the unified set.
///
AliasSet *AliasSetTracker::findAliasSetForPointer(const Value *Ptr,
uint64_t Size,
const MDNode *TBAAInfo) {
AliasSet *FoundSet = 0;
for (iterator I = begin(), E = end(); I != E; ++I) {
if (I->Forward || !I->aliasesPointer(Ptr, Size, TBAAInfo, AA)) continue;
if (FoundSet == 0) { // If this is the first alias set ptr can go into.
FoundSet = I; // Remember it.
} else { // Otherwise, we must merge the sets.
FoundSet->mergeSetIn(*I, *this); // Merge in contents.
}
}
return FoundSet;
}
/// containsPointer - Return true if the specified location is represented by
/// this alias set, false otherwise. This does not modify the AST object or
/// alias sets.
bool AliasSetTracker::containsPointer(Value *Ptr, uint64_t Size,
const MDNode *TBAAInfo) const {
for (const_iterator I = begin(), E = end(); I != E; ++I)
if (!I->Forward && I->aliasesPointer(Ptr, Size, TBAAInfo, AA))
return true;
return false;
}
AliasSet *AliasSetTracker::findAliasSetForUnknownInst(Instruction *Inst) {
AliasSet *FoundSet = 0;
for (iterator I = begin(), E = end(); I != E; ++I) {
if (I->Forward || !I->aliasesUnknownInst(Inst, AA))
continue;
if (FoundSet == 0) // If this is the first alias set ptr can go into.
FoundSet = I; // Remember it.
else if (!I->Forward) // Otherwise, we must merge the sets.
FoundSet->mergeSetIn(*I, *this); // Merge in contents.
}
return FoundSet;
}
/// getAliasSetForPointer - Return the alias set that the specified pointer
/// lives in.
AliasSet &AliasSetTracker::getAliasSetForPointer(Value *Pointer, uint64_t Size,
const MDNode *TBAAInfo,
bool *New) {
AliasSet::PointerRec &Entry = getEntryFor(Pointer);
// Check to see if the pointer is already known.
if (Entry.hasAliasSet()) {
Entry.updateSizeAndTBAAInfo(Size, TBAAInfo);
// Return the set!
return *Entry.getAliasSet(*this)->getForwardedTarget(*this);
}
if (AliasSet *AS = findAliasSetForPointer(Pointer, Size, TBAAInfo)) {
// Add it to the alias set it aliases.
AS->addPointer(*this, Entry, Size, TBAAInfo);
return *AS;
}
if (New) *New = true;
// Otherwise create a new alias set to hold the loaded pointer.
AliasSets.push_back(new AliasSet());
AliasSets.back().addPointer(*this, Entry, Size, TBAAInfo);
return AliasSets.back();
}
bool AliasSetTracker::add(Value *Ptr, uint64_t Size, const MDNode *TBAAInfo) {
bool NewPtr;
addPointer(Ptr, Size, TBAAInfo, AliasSet::NoModRef, NewPtr);
return NewPtr;
}
bool AliasSetTracker::add(LoadInst *LI) {
if (LI->getOrdering() > Monotonic) return addUnknown(LI);
AliasSet::AccessType ATy = AliasSet::Refs;
if (!LI->isUnordered()) ATy = AliasSet::ModRef;
bool NewPtr;
AliasSet &AS = addPointer(LI->getOperand(0),
AA.getTypeStoreSize(LI->getType()),
LI->getMetadata(LLVMContext::MD_tbaa),
ATy, NewPtr);
if (LI->isVolatile()) AS.setVolatile();
return NewPtr;
}
bool AliasSetTracker::add(StoreInst *SI) {
if (SI->getOrdering() > Monotonic) return addUnknown(SI);
AliasSet::AccessType ATy = AliasSet::Mods;
if (!SI->isUnordered()) ATy = AliasSet::ModRef;
bool NewPtr;
Value *Val = SI->getOperand(0);
AliasSet &AS = addPointer(SI->getOperand(1),
AA.getTypeStoreSize(Val->getType()),
SI->getMetadata(LLVMContext::MD_tbaa),
ATy, NewPtr);
if (SI->isVolatile()) AS.setVolatile();
return NewPtr;
}
bool AliasSetTracker::add(VAArgInst *VAAI) {
bool NewPtr;
addPointer(VAAI->getOperand(0), AliasAnalysis::UnknownSize,
VAAI->getMetadata(LLVMContext::MD_tbaa),
AliasSet::ModRef, NewPtr);
return NewPtr;
}
bool AliasSetTracker::addUnknown(Instruction *Inst) {
if (isa<DbgInfoIntrinsic>(Inst))
return true; // Ignore DbgInfo Intrinsics.
if (!Inst->mayReadOrWriteMemory())
return true; // doesn't alias anything
AliasSet *AS = findAliasSetForUnknownInst(Inst);
if (AS) {
AS->addUnknownInst(Inst, AA);
return false;
}
AliasSets.push_back(new AliasSet());
AS = &AliasSets.back();
AS->addUnknownInst(Inst, AA);
return true;
}
bool AliasSetTracker::add(Instruction *I) {
// Dispatch to one of the other add methods.
if (LoadInst *LI = dyn_cast<LoadInst>(I))
return add(LI);
if (StoreInst *SI = dyn_cast<StoreInst>(I))
return add(SI);
if (VAArgInst *VAAI = dyn_cast<VAArgInst>(I))
return add(VAAI);
return addUnknown(I);
}
void AliasSetTracker::add(BasicBlock &BB) {
for (BasicBlock::iterator I = BB.begin(), E = BB.end(); I != E; ++I)
add(I);
}
void AliasSetTracker::add(const AliasSetTracker &AST) {
assert(&AA == &AST.AA &&
"Merging AliasSetTracker objects with different Alias Analyses!");
// Loop over all of the alias sets in AST, adding the pointers contained
// therein into the current alias sets. This can cause alias sets to be
// merged together in the current AST.
for (const_iterator I = AST.begin(), E = AST.end(); I != E; ++I) {
if (I->Forward) continue; // Ignore forwarding alias sets
AliasSet &AS = const_cast<AliasSet&>(*I);
// If there are any call sites in the alias set, add them to this AST.
for (unsigned i = 0, e = AS.UnknownInsts.size(); i != e; ++i)
add(AS.UnknownInsts[i]);
// Loop over all of the pointers in this alias set.
bool X;
for (AliasSet::iterator ASI = AS.begin(), E = AS.end(); ASI != E; ++ASI) {
AliasSet &NewAS = addPointer(ASI.getPointer(), ASI.getSize(),
ASI.getTBAAInfo(),
(AliasSet::AccessType)AS.AccessTy, X);
if (AS.isVolatile()) NewAS.setVolatile();
}
}
}
/// remove - Remove the specified (potentially non-empty) alias set from the
/// tracker.
void AliasSetTracker::remove(AliasSet &AS) {
// Drop all call sites.
AS.UnknownInsts.clear();
// Clear the alias set.
unsigned NumRefs = 0;
while (!AS.empty()) {
AliasSet::PointerRec *P = AS.PtrList;
Value *ValToRemove = P->getValue();
// Unlink and delete entry from the list of values.
P->eraseFromList();
// Remember how many references need to be dropped.
++NumRefs;
// Finally, remove the entry.
PointerMap.erase(ValToRemove);
}
// Stop using the alias set, removing it.
AS.RefCount -= NumRefs;
if (AS.RefCount == 0)
AS.removeFromTracker(*this);
}
bool
AliasSetTracker::remove(Value *Ptr, uint64_t Size, const MDNode *TBAAInfo) {
AliasSet *AS = findAliasSetForPointer(Ptr, Size, TBAAInfo);
if (!AS) return false;
remove(*AS);
return true;
}
bool AliasSetTracker::remove(LoadInst *LI) {
uint64_t Size = AA.getTypeStoreSize(LI->getType());
const MDNode *TBAAInfo = LI->getMetadata(LLVMContext::MD_tbaa);
AliasSet *AS = findAliasSetForPointer(LI->getOperand(0), Size, TBAAInfo);
if (!AS) return false;
remove(*AS);
return true;
}
bool AliasSetTracker::remove(StoreInst *SI) {
uint64_t Size = AA.getTypeStoreSize(SI->getOperand(0)->getType());
const MDNode *TBAAInfo = SI->getMetadata(LLVMContext::MD_tbaa);
AliasSet *AS = findAliasSetForPointer(SI->getOperand(1), Size, TBAAInfo);
if (!AS) return false;
remove(*AS);
return true;
}
bool AliasSetTracker::remove(VAArgInst *VAAI) {
AliasSet *AS = findAliasSetForPointer(VAAI->getOperand(0),
AliasAnalysis::UnknownSize,
VAAI->getMetadata(LLVMContext::MD_tbaa));
if (!AS) return false;
remove(*AS);
return true;
}
bool AliasSetTracker::removeUnknown(Instruction *I) {
if (!I->mayReadOrWriteMemory())
return false; // doesn't alias anything
AliasSet *AS = findAliasSetForUnknownInst(I);
if (!AS) return false;
remove(*AS);
return true;
}
bool AliasSetTracker::remove(Instruction *I) {
// Dispatch to one of the other remove methods...
if (LoadInst *LI = dyn_cast<LoadInst>(I))
return remove(LI);
if (StoreInst *SI = dyn_cast<StoreInst>(I))
return remove(SI);
if (VAArgInst *VAAI = dyn_cast<VAArgInst>(I))
return remove(VAAI);
return removeUnknown(I);
}
// deleteValue method - This method is used to remove a pointer value from the
// AliasSetTracker entirely. It should be used when an instruction is deleted
// from the program to update the AST. If you don't use this, you would have
// dangling pointers to deleted instructions.
//
void AliasSetTracker::deleteValue(Value *PtrVal) {
// Notify the alias analysis implementation that this value is gone.
AA.deleteValue(PtrVal);
// If this is a call instruction, remove the callsite from the appropriate
// AliasSet (if present).
if (Instruction *Inst = dyn_cast<Instruction>(PtrVal)) {
if (Inst->mayReadOrWriteMemory()) {
// Scan all the alias sets to see if this call site is contained.
for (iterator I = begin(), E = end(); I != E; ++I) {
if (I->Forward) continue;
I->removeUnknownInst(Inst);
}
}
}
// First, look up the PointerRec for this pointer.
PointerMapType::iterator I = PointerMap.find_as(PtrVal);
if (I == PointerMap.end()) return; // Noop
// If we found one, remove the pointer from the alias set it is in.
AliasSet::PointerRec *PtrValEnt = I->second;
AliasSet *AS = PtrValEnt->getAliasSet(*this);
// Unlink and delete from the list of values.
PtrValEnt->eraseFromList();
// Stop using the alias set.
AS->dropRef(*this);
PointerMap.erase(I);
}
// copyValue - This method should be used whenever a preexisting value in the
// program is copied or cloned, introducing a new value. Note that it is ok for
// clients that use this method to introduce the same value multiple times: if
// the tracker already knows about a value, it will ignore the request.
//
void AliasSetTracker::copyValue(Value *From, Value *To) {
// Notify the alias analysis implementation that this value is copied.
AA.copyValue(From, To);
// First, look up the PointerRec for this pointer.
PointerMapType::iterator I = PointerMap.find_as(From);
if (I == PointerMap.end())
return; // Noop
assert(I->second->hasAliasSet() && "Dead entry?");
AliasSet::PointerRec &Entry = getEntryFor(To);
if (Entry.hasAliasSet()) return; // Already in the tracker!
// Add it to the alias set it aliases...
I = PointerMap.find_as(From);
AliasSet *AS = I->second->getAliasSet(*this);
AS->addPointer(*this, Entry, I->second->getSize(),
I->second->getTBAAInfo(),
true);
}
//===----------------------------------------------------------------------===//
// AliasSet/AliasSetTracker Printing Support
//===----------------------------------------------------------------------===//
void AliasSet::print(raw_ostream &OS) const {
OS << " AliasSet[" << (const void*)this << ", " << RefCount << "] ";
OS << (AliasTy == MustAlias ? "must" : "may") << " alias, ";
switch (AccessTy) {
case NoModRef: OS << "No access "; break;
case Refs : OS << "Ref "; break;
case Mods : OS << "Mod "; break;
case ModRef : OS << "Mod/Ref "; break;
default: llvm_unreachable("Bad value for AccessTy!");
}
if (isVolatile()) OS << "[volatile] ";
if (Forward)
OS << " forwarding to " << (void*)Forward;
if (!empty()) {
OS << "Pointers: ";
for (iterator I = begin(), E = end(); I != E; ++I) {
if (I != begin()) OS << ", ";
WriteAsOperand(OS << "(", I.getPointer());
OS << ", " << I.getSize() << ")";
}
}
if (!UnknownInsts.empty()) {
OS << "\n " << UnknownInsts.size() << " Unknown instructions: ";
for (unsigned i = 0, e = UnknownInsts.size(); i != e; ++i) {
if (i) OS << ", ";
WriteAsOperand(OS, UnknownInsts[i]);
}
}
OS << "\n";
}
void AliasSetTracker::print(raw_ostream &OS) const {
OS << "Alias Set Tracker: " << AliasSets.size() << " alias sets for "
<< PointerMap.size() << " pointer values.\n";
for (const_iterator I = begin(), E = end(); I != E; ++I)
I->print(OS);
OS << "\n";
}
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
void AliasSet::dump() const { print(dbgs()); }
void AliasSetTracker::dump() const { print(dbgs()); }
#endif
//===----------------------------------------------------------------------===//
// ASTCallbackVH Class Implementation
//===----------------------------------------------------------------------===//
void AliasSetTracker::ASTCallbackVH::deleted() {
assert(AST && "ASTCallbackVH called with a null AliasSetTracker!");
AST->deleteValue(getValPtr());
// this now dangles!
}
void AliasSetTracker::ASTCallbackVH::allUsesReplacedWith(Value *V) {
AST->copyValue(getValPtr(), V);
}
AliasSetTracker::ASTCallbackVH::ASTCallbackVH(Value *V, AliasSetTracker *ast)
: CallbackVH(V), AST(ast) {}
AliasSetTracker::ASTCallbackVH &
AliasSetTracker::ASTCallbackVH::operator=(Value *V) {
return *this = ASTCallbackVH(V, AST);
}
//===----------------------------------------------------------------------===//
// AliasSetPrinter Pass
//===----------------------------------------------------------------------===//
namespace {
class AliasSetPrinter : public FunctionPass {
AliasSetTracker *Tracker;
public:
static char ID; // Pass identification, replacement for typeid
AliasSetPrinter() : FunctionPass(ID) {
initializeAliasSetPrinterPass(*PassRegistry::getPassRegistry());
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<AliasAnalysis>();
}
virtual bool runOnFunction(Function &F) {
Tracker = new AliasSetTracker(getAnalysis<AliasAnalysis>());
for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
Tracker->add(&*I);
Tracker->print(errs());
delete Tracker;
return false;
}
};
}
char AliasSetPrinter::ID = 0;
INITIALIZE_PASS_BEGIN(AliasSetPrinter, "print-alias-sets",
"Alias Set Printer", false, true)
INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
INITIALIZE_PASS_END(AliasSetPrinter, "print-alias-sets",
"Alias Set Printer", false, true)