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losslessCastableTypes is moved to Type class

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getStructOffsetType supports array indexing


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1343 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2001-11-26 16:59:47 +00:00
parent 12739d9f87
commit 89a1c806ea
1 changed files with 131 additions and 48 deletions
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179
lib/Transforms/TransformInternals.cpp
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@ -9,6 +9,8 @@
#include "llvm/Method.h"
#include "llvm/Type.h"
#include "llvm/ConstPoolVals.h"
#include "llvm/Analysis/Expressions.h"
#include "llvm/iOther.h"
// TargetData Hack: Eventually we will have annotations given to us by the
// backend so that we know stuff about type size and alignments. For now
@ -16,36 +18,6 @@
//
const TargetData TD("LevelRaise: Should be GCC though!");
// losslessCastableTypes - Return true if the types are bitwise equivalent.
// This predicate returns true if it is possible to cast from one type to
// another without gaining or losing precision, or altering the bits in any way.
//
bool losslessCastableTypes(const Type *T1, const Type *T2) {
if (!T1->isPrimitiveType() && !T1->isPointerType()) return false;
if (!T2->isPrimitiveType() && !T2->isPointerType()) return false;
if (T1->getPrimitiveID() == T2->getPrimitiveID())
return true; // Handles identity cast, and cast of differing pointer types
// Now we know that they are two differing primitive or pointer types
switch (T1->getPrimitiveID()) {
case Type::UByteTyID: return T2 == Type::SByteTy;
case Type::SByteTyID: return T2 == Type::UByteTy;
case Type::UShortTyID: return T2 == Type::ShortTy;
case Type::ShortTyID: return T2 == Type::UShortTy;
case Type::UIntTyID: return T2 == Type::IntTy;
case Type::IntTyID: return T2 == Type::UIntTy;
case Type::ULongTyID:
case Type::LongTyID:
case Type::PointerTyID:
return T2 == Type::ULongTy || T2 == Type::LongTy ||
T2->getPrimitiveID() == Type::PointerTyID;
default:
return false; // Other types have no identity values
}
}
// ReplaceInstWithValue - Replace all uses of an instruction (specified by BI)
// with a value, then remove and delete the original instruction.
//
@ -100,32 +72,143 @@ void ReplaceInstWithInst(BasicBlock::InstListType &BIL,
// false if you want a leaf
//
const Type *getStructOffsetType(const Type *Ty, unsigned &Offset,
vector<ConstPoolVal*> &Offsets,
vector<Value*> &Offsets,
bool StopEarly = true) {
if (!isa<StructType>(Ty) || (Offset == 0 && StopEarly && !Offsets.empty())) {
if (!isa<CompositeType>(Ty) ||
(Offset == 0 && StopEarly && !Offsets.empty())) {
Offset = 0; // Return the offset that we were able to acheive
return Ty; // Return the leaf type
}
assert(Offset < TD.getTypeSize(Ty) && "Offset not in struct!");
const StructType *STy = cast<StructType>(Ty);
const StructLayout *SL = TD.getStructLayout(STy);
unsigned ThisOffset;
const Type *NextType;
if (const StructType *STy = dyn_cast<StructType>(Ty)) {
assert(Offset < TD.getTypeSize(Ty) && "Offset not in composite!");
const StructLayout *SL = TD.getStructLayout(STy);
// This loop terminates always on a 0 <= i < MemberOffsets.size()
unsigned i;
for (i = 0; i < SL->MemberOffsets.size()-1; ++i)
if (Offset >= SL->MemberOffsets[i] && Offset < SL->MemberOffsets[i+1])
break;
// This loop terminates always on a 0 <= i < MemberOffsets.size()
unsigned i;
for (i = 0; i < SL->MemberOffsets.size()-1; ++i)
if (Offset >= SL->MemberOffsets[i] && Offset < SL->MemberOffsets[i+1])
break;
assert(Offset >= SL->MemberOffsets[i] &&
(i == SL->MemberOffsets.size()-1 || Offset < SL->MemberOffsets[i+1]));
assert(Offset >= SL->MemberOffsets[i] &&
(i == SL->MemberOffsets.size()-1 || Offset <SL->MemberOffsets[i+1]));
// Make sure to save the current index...
Offsets.push_back(ConstPoolUInt::get(Type::UByteTy, i));
ThisOffset = SL->MemberOffsets[i];
NextType = STy->getElementTypes()[i];
} else {
const ArrayType *ATy = cast<ArrayType>(Ty);
assert(ATy->isUnsized() || Offset < TD.getTypeSize(Ty) &&
"Offset not in composite!");
// Make sure to save the current index...
Offsets.push_back(ConstPoolUInt::get(Type::UByteTy, i));
NextType = ATy->getElementType();
unsigned ChildSize = TD.getTypeSize(NextType);
Offsets.push_back(ConstPoolUInt::get(Type::UIntTy, Offset/ChildSize));
ThisOffset = (Offset/ChildSize)*ChildSize;
}
unsigned SubOffs = Offset - SL->MemberOffsets[i];
const Type *LeafTy = getStructOffsetType(STy->getElementTypes()[i], SubOffs,
Offsets);
Offset = SL->MemberOffsets[i] + SubOffs;
unsigned SubOffs = Offset - ThisOffset;
const Type *LeafTy = getStructOffsetType(NextType, SubOffs, Offsets);
Offset = ThisOffset + SubOffs;
return LeafTy;
}
// ConvertableToGEP - This function returns true if the specified value V is
// a valid index into a pointer of type Ty. If it is valid, Idx is filled in
// with the values that would be appropriate to make this a getelementptr
// instruction. The type returned is the root type that the GEP would point to
//
const Type *ConvertableToGEP(const Type *Ty, Value *OffsetVal,
vector<Value*> &Indices,
BasicBlock::iterator *BI = 0) {
const CompositeType *CompTy = getPointedToComposite(Ty);
if (CompTy == 0) return 0;
// See if the cast is of an integer expression that is either a constant,
// or a value scaled by some amount with a possible offset.
//
analysis::ExprType Expr = analysis::ClassifyExpression(OffsetVal);
// The expression must either be a constant, or a scaled index to be useful
if (!Expr.Offset && !Expr.Scale)
return 0;
// Get the offset and scale now...
unsigned Offset = 0, Scale = Expr.Var != 0;
// Get the offset value if it exists...
if (Expr.Offset) {
int Val = getConstantValue(Expr.Offset);
if (Val < 0) return false; // Don't mess with negative offsets
Offset = (unsigned)Val;
}
// Get the scale value if it exists...
if (Expr.Scale) {
int Val = getConstantValue(Expr.Scale);
if (Val < 0) return false; // Don't mess with negative scales
Scale = (unsigned)Val;
}
// Check to make sure the offset is not negative or really large, outside the
// scope of this structure...
//
if (!isa<ArrayType>(CompTy) || cast<ArrayType>(CompTy)->isSized())
if (Offset >= TD.getTypeSize(CompTy))
return 0;
// Loop over the Scale and Offset values, filling in the Indices vector for
// our final getelementptr instruction.
//
const Type *NextTy = CompTy;
do {
if (!isa<CompositeType>(NextTy))
return 0; // Type must not be ready for processing...
CompTy = cast<CompositeType>(NextTy);
if (const StructType *StructTy = dyn_cast<StructType>(CompTy)) {
const StructLayout *SL = TD.getStructLayout(StructTy);
unsigned ActualOffset = Offset;
NextTy = getStructOffsetType(StructTy, ActualOffset, Indices);
Offset -= ActualOffset;
} else {
const ArrayType *AT = cast<ArrayType>(CompTy);
const Type *ElTy = AT->getElementType();
unsigned ElSize = TD.getTypeSize(ElTy);
// See if the user is indexing into a different cell of this array...
if (Offset >= ElSize) {
// Calculate the index that we are entering into the array cell with
unsigned Index = Offset/ElSize;
Indices.push_back(ConstPoolUInt::get(Type::UIntTy, Index));
Offset -= Index*ElSize; // Consume part of the offset
} else if (Scale && Scale != 1) {
// Must be indexing into this element with a variable...
if (Scale != ElSize)
return 0; // Type must not be finished yet...
if (Expr.Var->getType() != Type::UIntTy && BI) {
BasicBlock *BB = (**BI)->getParent();
CastInst *IdxCast = new CastInst(Expr.Var, Type::UIntTy);
*BI = BB->getInstList().insert(*BI, IdxCast)+1;
Expr.Var = IdxCast;
}
Indices.push_back(Expr.Var);
Scale = 0; // Consume scale factor!
} else {
// Must be indexing a small amount into the first cell of the array
// Just index into element zero of the array here.
//
Indices.push_back(ConstPoolUInt::get(Type::UIntTy, 0));
}
NextTy = ElTy;
}
} while (Offset || Scale); // Go until we're done!
return NextTy;
}