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Add support for "physical subtyping", which fixes:

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DSGraph/2003-06-29-NodeCollapsing2.ll & DSGraph/PhysicalSubtyping.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@6982 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2003-06-29 20:27:45 +00:00
parent 889fb9de96
commit 5c5b10f46a
1 changed files with 140 additions and 5 deletions
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145
lib/Analysis/DataStructure/DataStructure.cpp
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@ -143,6 +143,121 @@ bool DSNode::isNodeCompletelyFolded() const {
}
namespace {
/// TypeElementWalker Class - Used for implementation of physical subtyping...
///
class TypeElementWalker {
struct StackState {
const Type *Ty;
unsigned Offset;
unsigned Idx;
StackState(const Type *T, unsigned Off = 0)
: Ty(T), Offset(Off), Idx(0) {}
};
std::vector<StackState> Stack;
public:
TypeElementWalker(const Type *T) {
Stack.push_back(T);
StepToLeaf();
}
bool isDone() const { return Stack.empty(); }
const Type *getCurrentType() const { return Stack.back().Ty; }
unsigned getCurrentOffset() const { return Stack.back().Offset; }
void StepToNextType() {
PopStackAndAdvance();
StepToLeaf();
}
private:
/// PopStackAndAdvance - Pop the current element off of the stack and
/// advance the underlying element to the next contained member.
void PopStackAndAdvance() {
assert(!Stack.empty() && "Cannot pop an empty stack!");
Stack.pop_back();
while (!Stack.empty()) {
StackState &SS = Stack.back();
if (const StructType *ST = dyn_cast<StructType>(SS.Ty)) {
++SS.Idx;
if (SS.Idx != ST->getElementTypes().size()) {
const StructLayout *SL = TD.getStructLayout(ST);
SS.Offset += SL->MemberOffsets[SS.Idx]-SL->MemberOffsets[SS.Idx-1];
return;
}
Stack.pop_back(); // At the end of the structure
} else {
const ArrayType *AT = cast<ArrayType>(SS.Ty);
++SS.Idx;
if (SS.Idx != AT->getNumElements()) {
SS.Offset += TD.getTypeSize(AT->getElementType());
return;
}
Stack.pop_back(); // At the end of the array
}
}
}
/// StepToLeaf - Used by physical subtyping to move to the first leaf node
/// on the type stack.
void StepToLeaf() {
if (Stack.empty()) return;
while (!Stack.empty() && !Stack.back().Ty->isFirstClassType()) {
StackState &SS = Stack.back();
if (const StructType *ST = dyn_cast<StructType>(SS.Ty)) {
if (ST->getElementTypes().empty()) {
assert(SS.Idx == 0);
PopStackAndAdvance();
} else {
// Step into the structure...
assert(SS.Idx < ST->getElementTypes().size());
const StructLayout *SL = TD.getStructLayout(ST);
Stack.push_back(StackState(ST->getElementTypes()[SS.Idx],
SS.Offset+SL->MemberOffsets[SS.Idx]));
}
} else {
const ArrayType *AT = cast<ArrayType>(SS.Ty);
if (AT->getNumElements() == 0) {
assert(SS.Idx == 0);
PopStackAndAdvance();
} else {
// Step into the array...
assert(SS.Idx < AT->getNumElements());
Stack.push_back(StackState(AT->getElementType(),
SS.Offset+SS.Idx*
TD.getTypeSize(AT->getElementType())));
}
}
}
}
};
}
/// ElementTypesAreCompatible - Check to see if the specified types are
/// "physically" compatible. If so, return true, else return false. We only
/// have to check the fields in T1: T2 may be larger than T1.
///
static bool ElementTypesAreCompatible(const Type *T1, const Type *T2) {
TypeElementWalker T1W(T1), T2W(T2);
while (!T1W.isDone() && !T2W.isDone()) {
if (T1W.getCurrentOffset() != T2W.getCurrentOffset())
return false;
const Type *T1 = T1W.getCurrentType();
const Type *T2 = T2W.getCurrentType();
if (T1 != T2 && !T1->isLosslesslyConvertibleTo(T2))
return false;
T1W.StepToNextType();
T2W.StepToNextType();
}
return T1W.isDone();
}
/// mergeTypeInfo - This method merges the specified type into the current node
/// at the specified offset. This may update the current node's type record if
/// this gives more information to the node, it may do nothing to the node if
@ -218,8 +333,8 @@ bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset,
}
if (Offset) { // We could handle this case, but we don't for now...
DEBUG(std::cerr << "UNIMP: Trying to merge a growth type into "
<< "offset != 0: Collapsing!\n");
std::cerr << "UNIMP: Trying to merge a growth type into "
<< "offset != 0: Collapsing!\n";
if (FoldIfIncompatible) foldNodeCompletely();
return true;
}
@ -287,12 +402,22 @@ bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset,
// If we found our type exactly, early exit
if (SubType == NewTy) return false;
unsigned SubTypeSize = SubType->isSized() ? TD.getTypeSize(SubType) : 0;
// Ok, we are getting desperate now. Check for physical subtyping, where we
// just require each element in the node to be compatible.
assert(NewTySize <= SubTypeSize &&
"Expected smaller type merging into this one!");
if (NewTySize && NewTySize < 256 &&
SubTypeSize && SubTypeSize < 256 &&
ElementTypesAreCompatible(NewTy, SubType))
return false;
// Okay, so we found the leader type at the offset requested. Search the list
// of types that starts at this offset. If SubType is currently an array or
// structure, the type desired may actually be the first element of the
// composite type...
//
unsigned SubTypeSize = SubType->isSized() ? TD.getTypeSize(SubType) : 0;
unsigned PadSize = SubTypeSize; // Size, including pad memory which is ignored
while (SubType != NewTy) {
const Type *NextSubType = 0;
@ -351,7 +476,6 @@ bool DSNode::mergeTypeInfo(const Type *NewTy, unsigned Offset,
return false;
}
DEBUG(std::cerr << "MergeTypeInfo Folding OrigTy: " << Ty
<< "\n due to:" << NewTy << " @ " << Offset << "!\n"
<< "SubType: " << SubType << "\n\n");
@ -444,7 +568,18 @@ void DSNode::MergeNodes(DSNodeHandle& CurNodeH, DSNodeHandle& NH) {
unsigned NOffset = CurNodeH.getOffset()-NH.getOffset();
unsigned NSize = NH.getNode()->getSize();
// Merge the type entries of the two nodes together...
// If the two nodes are of different size, and the smaller node has the array
// bit set, collapse!
if (NSize != CurNodeH.getNode()->getSize()) {
if (NSize < CurNodeH.getNode()->getSize()) {
if (NH.getNode()->isArray())
NH.getNode()->foldNodeCompletely();
} else if (CurNodeH.getNode()->isArray()) {
NH.getNode()->foldNodeCompletely();
}
}
// Merge the type entries of the two nodes together...
if (NH.getNode()->Ty != Type::VoidTy)
CurNodeH.getNode()->mergeTypeInfo(NH.getNode()->Ty, NOffset);
assert(!CurNodeH.getNode()->isDeadNode());