llvm-project/llvm/lib/Analysis/AliasSetTracker.cpp

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//===- 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/Instructions.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Pass.h"
#include "llvm/Type.h"
#include "llvm/Target/TargetData.h"
#include "llvm/Assembly/Writer.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/InstIterator.h"
#include "llvm/Support/Streams.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;
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(L->getValue(), L->getSize(), R->getValue(), R->getSize())
!= AliasAnalysis::MustAlias)
AliasTy = MayAlias;
}
if (CallSites.empty()) { // Merge call sites...
if (!AS.CallSites.empty())
std::swap(CallSites, AS.CallSites);
} else if (!AS.CallSites.empty()) {
CallSites.insert(CallSites.end(), AS.CallSites.begin(), AS.CallSites.end());
AS.CallSites.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;
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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,
unsigned Size, 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()) {
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AliasAnalysis &AA = AST.getAliasAnalysis();
AliasAnalysis::AliasResult Result =
AA.alias(P->getValue(), P->getSize(), Entry.getValue(), Size);
if (Result == AliasAnalysis::MayAlias)
AliasTy = MayAlias;
else // First entry of must alias must have maximum size!
P->updateSize(Size);
assert(Result != AliasAnalysis::NoAlias && "Cannot be part of must set!");
}
Entry.setAliasSet(this);
Entry.updateSize(Size);
// Add it to the end of the list...
assert(*PtrListEnd == 0 && "End of list is not null?");
*PtrListEnd = &Entry;
PtrListEnd = Entry.setPrevInList(PtrListEnd);
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assert(*PtrListEnd == 0 && "End of list is not null?");
addRef(); // Entry points to alias set...
}
void AliasSet::addCallSite(CallSite CS, AliasAnalysis &AA) {
CallSites.push_back(CS);
AliasAnalysis::ModRefBehavior Behavior = AA.getModRefBehavior(CS);
if (Behavior == AliasAnalysis::DoesNotAccessMemory)
return;
else if (Behavior == AliasAnalysis::OnlyReadsMemory) {
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, unsigned Size,
AliasAnalysis &AA) const {
if (AliasTy == MustAlias) {
assert(CallSites.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(SomePtr->getValue(), SomePtr->getSize(), Ptr, Size);
}
// 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(Ptr, Size, I.getPointer(), I.getSize()))
return true;
// Check the call sites list and invoke list...
if (!CallSites.empty()) {
if (AA.hasNoModRefInfoForCalls())
return true;
for (unsigned i = 0, e = CallSites.size(); i != e; ++i)
if (AA.getModRefInfo(CallSites[i], const_cast<Value*>(Ptr), Size)
!= AliasAnalysis::NoModRef)
return true;
}
return false;
}
bool AliasSet::aliasesCallSite(CallSite CS, AliasAnalysis &AA) const {
if (AA.doesNotAccessMemory(CS))
return false;
if (AA.hasNoModRefInfoForCalls())
return true;
for (unsigned i = 0, e = CallSites.size(); i != e; ++i)
if (AA.getModRefInfo(CallSites[i], CS) != AliasAnalysis::NoModRef ||
AA.getModRefInfo(CS, CallSites[i]) != AliasAnalysis::NoModRef)
return true;
for (iterator I = begin(), E = end(); I != E; ++I)
if (AA.getModRefInfo(CS, I.getPointer(), I.getSize()) !=
AliasAnalysis::NoModRef)
return true;
return false;
}
void AliasSetTracker::clear() {
// Delete all the PointerRec entries.
for (DenseMap<Value*, AliasSet::PointerRec*>::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,
unsigned Size) {
AliasSet *FoundSet = 0;
for (iterator I = begin(), E = end(); I != E; ++I)
if (!I->Forward && I->aliasesPointer(Ptr, Size, AA)) {
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;
}
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/// 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, unsigned Size) const {
for (const_iterator I = begin(), E = end(); I != E; ++I)
if (!I->Forward && I->aliasesPointer(Ptr, Size, AA))
return true;
return false;
}
AliasSet *AliasSetTracker::findAliasSetForCallSite(CallSite CS) {
AliasSet *FoundSet = 0;
for (iterator I = begin(), E = end(); I != E; ++I)
if (!I->Forward && I->aliasesCallSite(CS, AA)) {
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, unsigned Size,
bool *New) {
AliasSet::PointerRec &Entry = getEntryFor(Pointer);
// Check to see if the pointer is already known...
if (Entry.hasAliasSet()) {
Entry.updateSize(Size);
// Return the set!
return *Entry.getAliasSet(*this)->getForwardedTarget(*this);
} else if (AliasSet *AS = findAliasSetForPointer(Pointer, Size)) {
// Add it to the alias set it aliases...
AS->addPointer(*this, Entry, Size);
return *AS;
} else {
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);
return AliasSets.back();
}
}
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bool AliasSetTracker::add(Value *Ptr, unsigned Size) {
bool NewPtr;
addPointer(Ptr, Size, AliasSet::NoModRef, NewPtr);
return NewPtr;
}
bool AliasSetTracker::add(LoadInst *LI) {
bool NewPtr;
AliasSet &AS = addPointer(LI->getOperand(0),
Executive summary: getTypeSize -> getTypeStoreSize / getABITypeSize. The meaning of getTypeSize was not clear - clarifying it is important now that we have x86 long double and arbitrary precision integers. The issue with long double is that it requires 80 bits, and this is not a multiple of its alignment. This gives a primitive type for which getTypeSize differed from getABITypeSize. For arbitrary precision integers it is even worse: there is the minimum number of bits needed to hold the type (eg: 36 for an i36), the maximum number of bits that will be overwriten when storing the type (40 bits for i36) and the ABI size (i.e. the storage size rounded up to a multiple of the alignment; 64 bits for i36). This patch removes getTypeSize (not really - it is still there but deprecated to allow for a gradual transition). Instead there is: (1) getTypeSizeInBits - a number of bits that suffices to hold all values of the type. For a primitive type, this is the minimum number of bits. For an i36 this is 36 bits. For x86 long double it is 80. This corresponds to gcc's TYPE_PRECISION. (2) getTypeStoreSizeInBits - the maximum number of bits that is written when storing the type (or read when reading it). For an i36 this is 40 bits, for an x86 long double it is 80 bits. This is the size alias analysis is interested in (getTypeStoreSize returns the number of bytes). There doesn't seem to be anything corresponding to this in gcc. (3) getABITypeSizeInBits - this is getTypeStoreSizeInBits rounded up to a multiple of the alignment. For an i36 this is 64, for an x86 long double this is 96 or 128 depending on the OS. This is the spacing between consecutive elements when you form an array out of this type (getABITypeSize returns the number of bytes). This is TYPE_SIZE in gcc. Since successive elements in a SequentialType (arrays, pointers and vectors) need to be aligned, the spacing between them will be given by getABITypeSize. This means that the size of an array is the length times the getABITypeSize. It also means that GEP computations need to use getABITypeSize when computing offsets. Furthermore, if an alloca allocates several elements at once then these too need to be aligned, so the size of the alloca has to be the number of elements multiplied by getABITypeSize. Logically speaking this doesn't have to be the case when allocating just one element, but it is simpler to also use getABITypeSize in this case. So alloca's and mallocs should use getABITypeSize. Finally, since gcc's only notion of size is that given by getABITypeSize, if you want to output assembler etc the same as gcc then getABITypeSize is the size you want. Since a store will overwrite no more than getTypeStoreSize bytes, and a read will read no more than that many bytes, this is the notion of size appropriate for alias analysis calculations. In this patch I have corrected all type size uses except some of those in ScalarReplAggregates, lib/Codegen, lib/Target (the hard cases). I will get around to auditing these too at some point, but I could do with some help. Finally, I made one change which I think wise but others might consider pointless and suboptimal: in an unpacked struct the amount of space allocated for a field is now given by the ABI size rather than getTypeStoreSize. I did this because every other place that reserves memory for a type (eg: alloca) now uses getABITypeSize, and I didn't want to make an exception for unpacked structs, i.e. I did it to make things more uniform. This only effects structs containing long doubles and arbitrary precision integers. If someone wants to pack these types more tightly they can always use a packed struct. llvm-svn: 43620
2007-11-02 04:53:16 +08:00
AA.getTargetData().getTypeStoreSize(LI->getType()),
AliasSet::Refs, NewPtr);
if (LI->isVolatile()) AS.setVolatile();
return NewPtr;
}
bool AliasSetTracker::add(StoreInst *SI) {
bool NewPtr;
Value *Val = SI->getOperand(0);
AliasSet &AS = addPointer(SI->getOperand(1),
Executive summary: getTypeSize -> getTypeStoreSize / getABITypeSize. The meaning of getTypeSize was not clear - clarifying it is important now that we have x86 long double and arbitrary precision integers. The issue with long double is that it requires 80 bits, and this is not a multiple of its alignment. This gives a primitive type for which getTypeSize differed from getABITypeSize. For arbitrary precision integers it is even worse: there is the minimum number of bits needed to hold the type (eg: 36 for an i36), the maximum number of bits that will be overwriten when storing the type (40 bits for i36) and the ABI size (i.e. the storage size rounded up to a multiple of the alignment; 64 bits for i36). This patch removes getTypeSize (not really - it is still there but deprecated to allow for a gradual transition). Instead there is: (1) getTypeSizeInBits - a number of bits that suffices to hold all values of the type. For a primitive type, this is the minimum number of bits. For an i36 this is 36 bits. For x86 long double it is 80. This corresponds to gcc's TYPE_PRECISION. (2) getTypeStoreSizeInBits - the maximum number of bits that is written when storing the type (or read when reading it). For an i36 this is 40 bits, for an x86 long double it is 80 bits. This is the size alias analysis is interested in (getTypeStoreSize returns the number of bytes). There doesn't seem to be anything corresponding to this in gcc. (3) getABITypeSizeInBits - this is getTypeStoreSizeInBits rounded up to a multiple of the alignment. For an i36 this is 64, for an x86 long double this is 96 or 128 depending on the OS. This is the spacing between consecutive elements when you form an array out of this type (getABITypeSize returns the number of bytes). This is TYPE_SIZE in gcc. Since successive elements in a SequentialType (arrays, pointers and vectors) need to be aligned, the spacing between them will be given by getABITypeSize. This means that the size of an array is the length times the getABITypeSize. It also means that GEP computations need to use getABITypeSize when computing offsets. Furthermore, if an alloca allocates several elements at once then these too need to be aligned, so the size of the alloca has to be the number of elements multiplied by getABITypeSize. Logically speaking this doesn't have to be the case when allocating just one element, but it is simpler to also use getABITypeSize in this case. So alloca's and mallocs should use getABITypeSize. Finally, since gcc's only notion of size is that given by getABITypeSize, if you want to output assembler etc the same as gcc then getABITypeSize is the size you want. Since a store will overwrite no more than getTypeStoreSize bytes, and a read will read no more than that many bytes, this is the notion of size appropriate for alias analysis calculations. In this patch I have corrected all type size uses except some of those in ScalarReplAggregates, lib/Codegen, lib/Target (the hard cases). I will get around to auditing these too at some point, but I could do with some help. Finally, I made one change which I think wise but others might consider pointless and suboptimal: in an unpacked struct the amount of space allocated for a field is now given by the ABI size rather than getTypeStoreSize. I did this because every other place that reserves memory for a type (eg: alloca) now uses getABITypeSize, and I didn't want to make an exception for unpacked structs, i.e. I did it to make things more uniform. This only effects structs containing long doubles and arbitrary precision integers. If someone wants to pack these types more tightly they can always use a packed struct. llvm-svn: 43620
2007-11-02 04:53:16 +08:00
AA.getTargetData().getTypeStoreSize(Val->getType()),
AliasSet::Mods, NewPtr);
if (SI->isVolatile()) AS.setVolatile();
return NewPtr;
}
bool AliasSetTracker::add(FreeInst *FI) {
bool NewPtr;
addPointer(FI->getOperand(0), ~0, AliasSet::Mods, NewPtr);
return NewPtr;
}
bool AliasSetTracker::add(VAArgInst *VAAI) {
bool NewPtr;
addPointer(VAAI->getOperand(0), ~0, AliasSet::ModRef, NewPtr);
return NewPtr;
}
bool AliasSetTracker::add(CallSite CS) {
if (isa<DbgInfoIntrinsic>(CS.getInstruction()))
return true; // Ignore DbgInfo Intrinsics.
if (AA.doesNotAccessMemory(CS))
return true; // doesn't alias anything
AliasSet *AS = findAliasSetForCallSite(CS);
if (!AS) {
AliasSets.push_back(new AliasSet());
AS = &AliasSets.back();
AS->addCallSite(CS, AA);
return true;
} else {
AS->addCallSite(CS, AA);
return false;
}
}
bool AliasSetTracker::add(Instruction *I) {
// Dispatch to one of the other add methods...
if (LoadInst *LI = dyn_cast<LoadInst>(I))
return add(LI);
else if (StoreInst *SI = dyn_cast<StoreInst>(I))
return add(SI);
else if (CallInst *CI = dyn_cast<CallInst>(I))
return add(CI);
else if (InvokeInst *II = dyn_cast<InvokeInst>(I))
return add(II);
else if (FreeInst *FI = dyn_cast<FreeInst>(I))
return add(FI);
else if (VAArgInst *VAAI = dyn_cast<VAArgInst>(I))
return add(VAAI);
return true;
}
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) { // 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.CallSites.size(); i != e; ++i)
add(AS.CallSites[i]);
// Loop over all of the pointers in this alias set...
AliasSet::iterator I = AS.begin(), E = AS.end();
bool X;
for (; I != E; ++I) {
AliasSet &NewAS = addPointer(I.getPointer(), I.getSize(),
(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.CallSites.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);
}
2004-07-26 13:50:23 +08:00
bool AliasSetTracker::remove(Value *Ptr, unsigned Size) {
AliasSet *AS = findAliasSetForPointer(Ptr, Size);
if (!AS) return false;
remove(*AS);
return true;
}
bool AliasSetTracker::remove(LoadInst *LI) {
Executive summary: getTypeSize -> getTypeStoreSize / getABITypeSize. The meaning of getTypeSize was not clear - clarifying it is important now that we have x86 long double and arbitrary precision integers. The issue with long double is that it requires 80 bits, and this is not a multiple of its alignment. This gives a primitive type for which getTypeSize differed from getABITypeSize. For arbitrary precision integers it is even worse: there is the minimum number of bits needed to hold the type (eg: 36 for an i36), the maximum number of bits that will be overwriten when storing the type (40 bits for i36) and the ABI size (i.e. the storage size rounded up to a multiple of the alignment; 64 bits for i36). This patch removes getTypeSize (not really - it is still there but deprecated to allow for a gradual transition). Instead there is: (1) getTypeSizeInBits - a number of bits that suffices to hold all values of the type. For a primitive type, this is the minimum number of bits. For an i36 this is 36 bits. For x86 long double it is 80. This corresponds to gcc's TYPE_PRECISION. (2) getTypeStoreSizeInBits - the maximum number of bits that is written when storing the type (or read when reading it). For an i36 this is 40 bits, for an x86 long double it is 80 bits. This is the size alias analysis is interested in (getTypeStoreSize returns the number of bytes). There doesn't seem to be anything corresponding to this in gcc. (3) getABITypeSizeInBits - this is getTypeStoreSizeInBits rounded up to a multiple of the alignment. For an i36 this is 64, for an x86 long double this is 96 or 128 depending on the OS. This is the spacing between consecutive elements when you form an array out of this type (getABITypeSize returns the number of bytes). This is TYPE_SIZE in gcc. Since successive elements in a SequentialType (arrays, pointers and vectors) need to be aligned, the spacing between them will be given by getABITypeSize. This means that the size of an array is the length times the getABITypeSize. It also means that GEP computations need to use getABITypeSize when computing offsets. Furthermore, if an alloca allocates several elements at once then these too need to be aligned, so the size of the alloca has to be the number of elements multiplied by getABITypeSize. Logically speaking this doesn't have to be the case when allocating just one element, but it is simpler to also use getABITypeSize in this case. So alloca's and mallocs should use getABITypeSize. Finally, since gcc's only notion of size is that given by getABITypeSize, if you want to output assembler etc the same as gcc then getABITypeSize is the size you want. Since a store will overwrite no more than getTypeStoreSize bytes, and a read will read no more than that many bytes, this is the notion of size appropriate for alias analysis calculations. In this patch I have corrected all type size uses except some of those in ScalarReplAggregates, lib/Codegen, lib/Target (the hard cases). I will get around to auditing these too at some point, but I could do with some help. Finally, I made one change which I think wise but others might consider pointless and suboptimal: in an unpacked struct the amount of space allocated for a field is now given by the ABI size rather than getTypeStoreSize. I did this because every other place that reserves memory for a type (eg: alloca) now uses getABITypeSize, and I didn't want to make an exception for unpacked structs, i.e. I did it to make things more uniform. This only effects structs containing long doubles and arbitrary precision integers. If someone wants to pack these types more tightly they can always use a packed struct. llvm-svn: 43620
2007-11-02 04:53:16 +08:00
unsigned Size = AA.getTargetData().getTypeStoreSize(LI->getType());
AliasSet *AS = findAliasSetForPointer(LI->getOperand(0), Size);
if (!AS) return false;
remove(*AS);
return true;
}
bool AliasSetTracker::remove(StoreInst *SI) {
Executive summary: getTypeSize -> getTypeStoreSize / getABITypeSize. The meaning of getTypeSize was not clear - clarifying it is important now that we have x86 long double and arbitrary precision integers. The issue with long double is that it requires 80 bits, and this is not a multiple of its alignment. This gives a primitive type for which getTypeSize differed from getABITypeSize. For arbitrary precision integers it is even worse: there is the minimum number of bits needed to hold the type (eg: 36 for an i36), the maximum number of bits that will be overwriten when storing the type (40 bits for i36) and the ABI size (i.e. the storage size rounded up to a multiple of the alignment; 64 bits for i36). This patch removes getTypeSize (not really - it is still there but deprecated to allow for a gradual transition). Instead there is: (1) getTypeSizeInBits - a number of bits that suffices to hold all values of the type. For a primitive type, this is the minimum number of bits. For an i36 this is 36 bits. For x86 long double it is 80. This corresponds to gcc's TYPE_PRECISION. (2) getTypeStoreSizeInBits - the maximum number of bits that is written when storing the type (or read when reading it). For an i36 this is 40 bits, for an x86 long double it is 80 bits. This is the size alias analysis is interested in (getTypeStoreSize returns the number of bytes). There doesn't seem to be anything corresponding to this in gcc. (3) getABITypeSizeInBits - this is getTypeStoreSizeInBits rounded up to a multiple of the alignment. For an i36 this is 64, for an x86 long double this is 96 or 128 depending on the OS. This is the spacing between consecutive elements when you form an array out of this type (getABITypeSize returns the number of bytes). This is TYPE_SIZE in gcc. Since successive elements in a SequentialType (arrays, pointers and vectors) need to be aligned, the spacing between them will be given by getABITypeSize. This means that the size of an array is the length times the getABITypeSize. It also means that GEP computations need to use getABITypeSize when computing offsets. Furthermore, if an alloca allocates several elements at once then these too need to be aligned, so the size of the alloca has to be the number of elements multiplied by getABITypeSize. Logically speaking this doesn't have to be the case when allocating just one element, but it is simpler to also use getABITypeSize in this case. So alloca's and mallocs should use getABITypeSize. Finally, since gcc's only notion of size is that given by getABITypeSize, if you want to output assembler etc the same as gcc then getABITypeSize is the size you want. Since a store will overwrite no more than getTypeStoreSize bytes, and a read will read no more than that many bytes, this is the notion of size appropriate for alias analysis calculations. In this patch I have corrected all type size uses except some of those in ScalarReplAggregates, lib/Codegen, lib/Target (the hard cases). I will get around to auditing these too at some point, but I could do with some help. Finally, I made one change which I think wise but others might consider pointless and suboptimal: in an unpacked struct the amount of space allocated for a field is now given by the ABI size rather than getTypeStoreSize. I did this because every other place that reserves memory for a type (eg: alloca) now uses getABITypeSize, and I didn't want to make an exception for unpacked structs, i.e. I did it to make things more uniform. This only effects structs containing long doubles and arbitrary precision integers. If someone wants to pack these types more tightly they can always use a packed struct. llvm-svn: 43620
2007-11-02 04:53:16 +08:00
unsigned Size =
AA.getTargetData().getTypeStoreSize(SI->getOperand(0)->getType());
AliasSet *AS = findAliasSetForPointer(SI->getOperand(1), Size);
if (!AS) return false;
remove(*AS);
return true;
}
bool AliasSetTracker::remove(FreeInst *FI) {
AliasSet *AS = findAliasSetForPointer(FI->getOperand(0), ~0);
if (!AS) return false;
remove(*AS);
return true;
}
bool AliasSetTracker::remove(VAArgInst *VAAI) {
AliasSet *AS = findAliasSetForPointer(VAAI->getOperand(0), ~0);
if (!AS) return false;
remove(*AS);
return true;
}
bool AliasSetTracker::remove(CallSite CS) {
if (AA.doesNotAccessMemory(CS))
return false; // doesn't alias anything
AliasSet *AS = findAliasSetForCallSite(CS);
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);
else if (StoreInst *SI = dyn_cast<StoreInst>(I))
return remove(SI);
else if (CallInst *CI = dyn_cast<CallInst>(I))
return remove(CI);
else if (FreeInst *FI = dyn_cast<FreeInst>(I))
return remove(FI);
else if (VAArgInst *VAAI = dyn_cast<VAArgInst>(I))
return remove(VAAI);
return true;
}
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// 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.
//
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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.
CallSite CS = CallSite::get(PtrVal);
if (CS.getInstruction())
if (!AA.doesNotAccessMemory(CS))
if (AliasSet *AS = findAliasSetForCallSite(CS))
AS->removeCallSite(CS);
// First, look up the PointerRec for this pointer.
DenseMap<Value*, AliasSet::PointerRec*>::iterator I = PointerMap.find(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.
DenseMap<Value*, AliasSet::PointerRec*>::iterator I = PointerMap.find(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(From);
AliasSet *AS = I->second->getAliasSet(*this);
AS->addPointer(*this, Entry, I->second->getSize(), true);
}
//===----------------------------------------------------------------------===//
// AliasSet/AliasSetTracker Printing Support
//===----------------------------------------------------------------------===//
void AliasSet::print(std::ostream &OS) const {
OS << " AliasSet[" << (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: assert(0 && "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 (!CallSites.empty()) {
OS << "\n " << CallSites.size() << " Call Sites: ";
for (unsigned i = 0, e = CallSites.size(); i != e; ++i) {
if (i) OS << ", ";
WriteAsOperand(OS, CallSites[i].getCalledValue());
}
}
OS << "\n";
}
void AliasSetTracker::print(std::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";
}
void AliasSet::dump() const { print (cerr); }
void AliasSetTracker::dump() const { print(cerr); }
//===----------------------------------------------------------------------===//
// AliasSetPrinter Pass
//===----------------------------------------------------------------------===//
namespace {
class VISIBILITY_HIDDEN AliasSetPrinter : public FunctionPass {
AliasSetTracker *Tracker;
public:
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static char ID; // Pass identification, replacement for typeid
AliasSetPrinter() : FunctionPass(&ID) {}
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(cerr);
delete Tracker;
return false;
}
};
}
char AliasSetPrinter::ID = 0;
static RegisterPass<AliasSetPrinter>
X("print-alias-sets", "Alias Set Printer", false, true);