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Several changes: 

* Simplify handling of byval, making it easier to understand and more 
    consistent.  This fixes PR2065.
  * Clean up and simplify handling of GEPs.  I can actually understand it now!
  * Implement support for GEP'ing into vectors, this fixes
    SingleSource/UnitTests/Vector/build2 among others.

llvm-svn: 47818
This commit is contained in:
Chris Lattner 2008-03-02 08:07:24 +00:00
parent e8338e52ed
commit 051709436e
1 changed files with 108 additions and 81 deletions
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189
llvm/lib/Target/CBackend/CBackend.cpp
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@ -87,7 +87,7 @@ namespace {
std::map<const Type *, std::string> TypeNames;
std::map<const ConstantFP *, unsigned> FPConstantMap;
std::set<Function*> intrinsicPrototypesAlreadyGenerated;
std::set<const Value*> ByValParams;
std::set<const Argument*> ByValParams;
public:
static char ID;
@ -122,8 +122,8 @@ namespace {
delete Mang;
FPConstantMap.clear();
TypeNames.clear();
intrinsicPrototypesAlreadyGenerated.clear();
ByValParams.clear();
intrinsicPrototypesAlreadyGenerated.clear();
return false;
}
@ -139,6 +139,20 @@ namespace {
void printStructReturnPointerFunctionType(std::ostream &Out,
const ParamAttrsList *PAL,
const PointerType *Ty);
/// writeOperandDeref - Print the result of dereferencing the specified
/// operand with '*'. This is equivalent to printing '*' then using
/// writeOperand, but avoids excess syntax in some cases.
void writeOperandDeref(Value *Operand) {
if (isAddressExposed(Operand)) {
// Already something with an address exposed.
writeOperandInternal(Operand);
} else {
Out << "*(";
writeOperand(Operand);
Out << ")";
}
}
void writeOperand(Value *Operand);
void writeOperandRaw(Value *Operand);
@ -170,8 +184,17 @@ namespace {
void printConstantWithCast(Constant *CPV, unsigned Opcode);
bool printConstExprCast(const ConstantExpr *CE);
void printConstantArray(ConstantArray *CPA);
void printConstantVector(ConstantVector *CP);
void printConstantVector(ConstantVector *CV);
/// isAddressExposed - Return true if the specified value's name needs to
/// have its address taken in order to get a C value of the correct type.
/// This happens for global variables, byval parameters, and direct allocas.
bool isAddressExposed(const Value *V) const {
if (const Argument *A = dyn_cast<Argument>(V))
return ByValParams.count(A);
return isa<GlobalVariable>(V) || isDirectAlloca(V);
}
// isInlinableInst - Attempt to inline instructions into their uses to build
// trees as much as possible. To do this, we have to consistently decide
// what is acceptable to inline, so that variable declarations don't get
@ -275,8 +298,8 @@ namespace {
BasicBlock *Successor, unsigned Indent);
void printBranchToBlock(BasicBlock *CurBlock, BasicBlock *SuccBlock,
unsigned Indent);
void printIndexingExpression(Value *Ptr, gep_type_iterator I,
gep_type_iterator E);
void printGEPExpression(Value *Ptr, gep_type_iterator I,
gep_type_iterator E);
std::string GetValueName(const Value *Operand);
};
@ -772,10 +795,10 @@ void CWriter::printConstant(Constant *CPV) {
return;
case Instruction::GetElementPtr:
Out << "(&(";
printIndexingExpression(CE->getOperand(0), gep_type_begin(CPV),
gep_type_end(CPV));
Out << "))";
Out << "(";
printGEPExpression(CE->getOperand(0), gep_type_begin(CPV),
gep_type_end(CPV));
Out << ")";
return;
case Instruction::Select:
Out << '(';
@ -1214,12 +1237,13 @@ void CWriter::writeOperandRaw(Value *Operand) {
}
void CWriter::writeOperand(Value *Operand) {
if (isa<GlobalVariable>(Operand) || isDirectAlloca(Operand))
bool isAddressImplicit = isAddressExposed(Operand);
if (isAddressImplicit)
Out << "(&"; // Global variables are referenced as their addresses by llvm
writeOperandInternal(Operand);
if (isa<GlobalVariable>(Operand) || isDirectAlloca(Operand))
if (isAddressImplicit)
Out << ')';
}
@ -1920,10 +1944,8 @@ void CWriter::printFunctionSignature(const Function *F, bool Prototype) {
ArgName = "";
const Type *ArgTy = I->getType();
if (PAL && PAL->paramHasAttr(Idx, ParamAttr::ByVal)) {
assert(isa<PointerType>(ArgTy));
ArgTy = cast<PointerType>(ArgTy)->getElementType();
const Value *Arg = &(*I);
ByValParams.insert(Arg);
ByValParams.insert(I);
}
printType(FunctionInnards, ArgTy,
/*isSigned=*/PAL && PAL->paramHasAttr(Idx, ParamAttr::SExt),
@ -2430,13 +2452,6 @@ void CWriter::visitCastInst(CastInst &I) {
// Make sure we really get a sext from bool by subtracing the bool from 0
Out << "0-";
}
// If it's a byval parameter being casted, then takes its address.
bool isByVal = ByValParams.count(I.getOperand(0));
if (isByVal) {
assert(I.getOpcode() == Instruction::BitCast &&
"ByVal aggregate parameter must ptr type");
Out << '&';
}
writeOperand(I.getOperand(0));
if (DstTy == Type::Int1Ty &&
(I.getOpcode() == Instruction::Trunc ||
@ -2666,10 +2681,7 @@ void CWriter::visitCallInst(CallInst &I) {
bool hasByVal = I.hasByValArgument();
bool isStructRet = I.isStructReturn();
if (isStructRet) {
bool isByVal = ByValParams.count(I.getOperand(1));
if (!isByVal) Out << "*(";
writeOperand(I.getOperand(1));
if (!isByVal) Out << ")";
writeOperandDeref(I.getOperand(1));
Out << " = ";
}
@ -2737,16 +2749,10 @@ void CWriter::visitCallInst(CallInst &I) {
Out << ')';
}
// Check if the argument is expected to be passed by value.
bool isOutByVal = PAL && PAL->paramHasAttr(ArgNo+1, ParamAttr::ByVal);
// Check if this argument itself is passed in by reference.
bool isInByVal = ByValParams.count(*AI);
if (isOutByVal && !isInByVal)
Out << "*(";
else if (!isOutByVal && isInByVal)
Out << "&(";
writeOperand(*AI);
if (isOutByVal ^ isInByVal)
Out << ")";
if (I.paramHasAttr(ArgNo+1, ParamAttr::ByVal))
writeOperandDeref(*AI);
else
writeOperand(*AI);
PrintedArg = true;
}
Out << ')';
@ -2858,7 +2864,7 @@ void CWriter::visitInlineAsm(CallInst &CI) {
Out << "__asm__ volatile (\"" << asmstr << "\"\n";
Out << " :";
for (std::vector<std::pair<std::string, Value*> >::iterator I = Output.begin(),
for (std::vector<std::pair<std::string, Value*> >::iterator I =Output.begin(),
E = Output.end(); I != E; ++I) {
Out << "\"" << I->first << "\"(";
writeOperandRaw(I->second);
@ -2901,61 +2907,85 @@ void CWriter::visitFreeInst(FreeInst &I) {
assert(0 && "lowerallocations pass didn't work!");
}
void CWriter::printIndexingExpression(Value *Ptr, gep_type_iterator I,
gep_type_iterator E) {
bool HasImplicitAddress = false;
// If accessing a global value with no indexing, avoid *(&GV) syndrome
if (isa<GlobalValue>(Ptr)) {
HasImplicitAddress = true;
} else if (isDirectAlloca(Ptr)) {
HasImplicitAddress = true;
}
void CWriter::printGEPExpression(Value *Ptr, gep_type_iterator I,
gep_type_iterator E) {
// If there are no indices, just print out the pointer.
if (I == E) {
if (!HasImplicitAddress)
Out << '*'; // Implicit zero first argument: '*x' is equivalent to 'x[0]'
writeOperandInternal(Ptr);
writeOperand(Ptr);
return;
}
const Constant *CI = dyn_cast<Constant>(I.getOperand());
if (HasImplicitAddress && (!CI || !CI->isNullValue()))
Out << "(&";
writeOperandInternal(Ptr);
if (HasImplicitAddress && (!CI || !CI->isNullValue())) {
Out << ')';
HasImplicitAddress = false; // HIA is only true if we haven't addressed yet
// Find out if the last index is into a vector. If so, we have to print this
// specially. Since vectors can't have elements of indexable type, only the
// last index could possibly be of a vector element.
const VectorType *LastIndexIsVector = 0;
{
for (gep_type_iterator TmpI = I; TmpI != E; ++TmpI)
LastIndexIsVector = dyn_cast<VectorType>(*TmpI);
}
Out << "(";
// If the last index is into a vector, we can't print it as &a[i][j] because
// we can't index into a vector with j in GCC. Instead, emit this as
// (((float*)&a[i])+j)
if (LastIndexIsVector) {
Out << "((";
printType(Out, PointerType::getUnqual(LastIndexIsVector->getElementType()));
Out << ")(";
}
Out << '&';
assert((!HasImplicitAddress || (CI && CI->isNullValue())) &&
"Can only have implicit address with direct accessing");
// If the first index is 0 (very typical) we can do a number of
// simplifications to clean up the code.
Value *FirstOp = I.getOperand();
if (!isa<Constant>(FirstOp) || !cast<Constant>(FirstOp)->isNullValue()) {
// First index isn't simple, print it the hard way.
writeOperand(Ptr);
} else {
++I; // Skip the zero index.
if (HasImplicitAddress) {
++I;
} else if (CI && CI->isNullValue()) {
gep_type_iterator TmpI = I; ++TmpI;
// Print out the -> operator if possible...
if (TmpI != E && isa<StructType>(*TmpI)) {
// Check if it's actually an aggregate parameter passed by value.
bool isByVal = ByValParams.count(Ptr);
Out << ((HasImplicitAddress || isByVal) ? "." : "->");
Out << "field" << cast<ConstantInt>(TmpI.getOperand())->getZExtValue();
I = ++TmpI;
// Okay, emit the first operand. If Ptr is something that is already address
// exposed, like a global, avoid emitting (&foo)[0], just emit foo instead.
if (isAddressExposed(Ptr)) {
writeOperandInternal(Ptr);
} else if (I != E && isa<StructType>(*I)) {
// If we didn't already emit the first operand, see if we can print it as
// P->f instead of "P[0].f"
writeOperand(Ptr);
Out << "->field" << cast<ConstantInt>(I.getOperand())->getZExtValue();
++I; // eat the struct index as well.
} else {
// Instead of emitting P[0][1], emit (*P)[1], which is more idiomatic.
Out << "(*";
writeOperand(Ptr);
Out << ")";
}
}
for (; I != E; ++I)
for (; I != E; ++I) {
if (isa<StructType>(*I)) {
Out << ".field" << cast<ConstantInt>(I.getOperand())->getZExtValue();
} else {
} else if (!isa<VectorType>(*I)) {
Out << '[';
writeOperandWithCast(I.getOperand(), Instruction::GetElementPtr);
Out << ']';
} else {
// If the last index is into a vector, then print it out as "+j)". This
// works with the 'LastIndexIsVector' code above.
if (isa<Constant>(I.getOperand()) &&
cast<Constant>(I.getOperand())->isNullValue()) {
Out << "))"; // avoid "+0".
} else {
Out << ")+(";
writeOperandWithCast(I.getOperand(), Instruction::GetElementPtr);
Out << "))";
}
}
}
Out << ")";
}
void CWriter::writeMemoryAccess(Value *Operand, const Type *OperandType,
@ -2989,14 +3019,12 @@ void CWriter::writeMemoryAccess(Value *Operand, const Type *OperandType,
}
void CWriter::visitLoadInst(LoadInst &I) {
writeMemoryAccess(I.getOperand(0), I.getType(), I.isVolatile(),
I.getAlignment());
}
void CWriter::visitStoreInst(StoreInst &I) {
writeMemoryAccess(I.getPointerOperand(), I.getOperand(0)->getType(),
I.isVolatile(), I.getAlignment());
Out << " = ";
@ -3018,9 +3046,8 @@ void CWriter::visitStoreInst(StoreInst &I) {
}
void CWriter::visitGetElementPtrInst(GetElementPtrInst &I) {
Out << '&';
printIndexingExpression(I.getPointerOperand(), gep_type_begin(I),
gep_type_end(I));
printGEPExpression(I.getPointerOperand(), gep_type_begin(I),
gep_type_end(I));
}
void CWriter::visitVAArgInst(VAArgInst &I) {