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Refactor struct initializers codegen.

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This not only reduces code duplication, but the unification
also enables code a la StructLiteralExp to handle classes
(for CTFE class constant support in 2.063).
This commit is contained in:
David Nadlinger
2013-06-12 15:36:15 +02:00
parent 2cebe6408c
commit 9a016a1002
7 changed files with 280 additions and 417 deletions
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408
ir/iraggr.cpp
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@@ -82,26 +82,12 @@ llvm::Constant * IrAggr::getDefaultInit()
if (constInit)
return constInit;
std::vector<LLConstant*> constants = type->ty == Tstruct ?
createStructDefaultInitializer() :
createClassDefaultInitializer();
// set initializer type body
std::vector<LLType*> types;
std::vector<LLConstant*>::iterator itr = constants.begin(), end = constants.end();
for (; itr != end; ++itr)
types.push_back((*itr)->getType());
init_type->setBody(types, packed);
// Whatever type we end up with due to unions, ..., it should match the
// the LLVM type corresponding to the D struct type in size.
assert(getTypeStoreSize(DtoType(type)) <= getTypeStoreSize(init_type) &&
"Struct initializer type mismatch, encountered type too small.");
// build constant struct
constInit = LLConstantStruct::get(init_type, constants);
IF_LOG Logger::cout() << "final default initializer: " << *constInit << std::endl;
IF_LOG Logger::println("Building default initializer for %s", aggrdecl->toPrettyChars());
LOG_SCOPE;
DtoType(type);
VarInitMap noExplicitInitializers;
constInit = createInitializerConstant(noExplicitInitializers, init_type);
return constInit;
}
@@ -109,25 +95,8 @@ llvm::Constant * IrAggr::getDefaultInit()
//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
// helper function that returns the static default initializer of a variable
LLConstant* get_default_initializer(VarDeclaration* vd, Initializer* init)
{
if (init)
{
return DtoConstInitializer(init->loc, vd->type, init);
}
else if (vd->init)
{
return DtoConstInitializer(vd->init->loc, vd->type, vd->init);
}
else
{
return DtoConstExpInit(vd->loc, vd->type, vd->type->defaultInit(vd->loc));
}
}
// helper function that adds zero bytes to a vector of constants
size_t add_zeros(std::vector<llvm::Constant*>& constants, size_t diff)
size_t add_zeros(llvm::SmallVectorImpl<llvm::Constant*>& constants, size_t diff)
{
size_t n = constants.size();
while (diff)
@@ -156,65 +125,6 @@ size_t add_zeros(std::vector<llvm::Constant*>& constants, size_t diff)
return constants.size() - n;
}
// Matches the way the type is built in IrTypeStruct
// maybe look at unifying the interface.
std::vector<llvm::Constant*> IrAggr::createStructDefaultInitializer()
{
IF_LOG Logger::println("Building default initializer for %s", aggrdecl->toPrettyChars());
LOG_SCOPE;
assert(type->ty == Tstruct && "cannot build struct default initializer for non struct type");
DtoType(type);
IrTypeStruct* ts = stripModifiers(type)->irtype->isStruct();
assert(ts);
// start at offset zero
size_t offset = 0;
// vector of constants
std::vector<llvm::Constant*> constants;
// go through fields
IrTypeAggr::iterator it;
for (it = ts->def_begin(); it != ts->def_end(); ++it)
{
VarDeclaration* vd = *it;
assert(vd->offset >= offset && "default fields not sorted by offset");
IF_LOG Logger::println("using field: %s %s (+%u)", vd->type->toChars(), vd->toChars(), vd->offset);
// get next aligned offset for this field
size_t alignedoffset = offset;
if (!packed)
{
alignedoffset = realignOffset(alignedoffset, vd->type);
}
// insert explicit padding?
if (alignedoffset < vd->offset)
{
add_zeros(constants, vd->offset - alignedoffset);
}
// add initializer
constants.push_back(get_default_initializer(vd, NULL));
// advance offset to right past this field
offset = vd->offset + vd->type->size();
}
// tail padding?
if (offset < aggrdecl->structsize)
{
add_zeros(constants, aggrdecl->structsize - offset);
}
return constants;
}
//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
@@ -229,97 +139,220 @@ LLConstant * IrAggr::createStructInitializer(StructInitializer * si)
assert(si->vars.dim == si->value.dim && "inconsistent StructInitializer");
// array of things to build
llvm::SmallVector<IrTypeStruct::VarInitConst, 16> data(aggrdecl->fields.dim);
// start by creating a map from initializer indices to field indices.
// I have no fucking clue why dmd represents it like this :/
size_t n = si->vars.dim;
LLSmallVector<int, 16> datamap(n, 0);
for (size_t i = 0; i < n; i++)
{
for (size_t j = 0; 1; j++)
{
assert(j < aggrdecl->fields.dim);
if (aggrdecl->fields.data[j] == si->vars.data[i])
{
datamap[i] = j;
break;
}
}
}
VarInitMap initConsts;
// fill in explicit initializers
n = si->vars.dim;
const size_t n = si->vars.dim;
for (size_t i = 0; i < n; i++)
{
VarDeclaration* vd = static_cast<VarDeclaration*>(si->vars.data[i]);
Initializer* ini = static_cast<Initializer*>(si->value.data[i]);
Loc loc = ini ? ini->loc : si->loc;
size_t idx = datamap[i];
// check for duplicate initialization
if (data[idx].first != NULL)
VarDeclaration* vd = si->vars[i];
Initializer* ini = si->value[i];
if (!ini)
{
Loc l = ini ? ini->loc : si->loc;
error(l, "duplicate initialization of %s", vd->toChars());
// Unclear when this occurs - createInitializerConstant will just
// fill in default initializer.
continue;
}
// check for overlapping initialization
for (size_t j = 0; j < i; j++)
VarInitMap::iterator it, end = initConsts.end();
for (it = initConsts.begin(); it != end; ++it)
{
size_t idx2 = datamap[j];
assert(data[idx2].first);
VarDeclarationIter it(aggrdecl->fields, idx2);
unsigned f_begin = it->offset;
unsigned f_end = f_begin + it->type->size();
if (vd->offset >= f_end || (vd->offset + vd->type->size()) <= f_begin)
if (it->first == vd)
{
error(ini->loc, "duplicate initialization of %s", vd->toChars());
continue;
}
error(loc, "initializer for %s overlaps previous initialization of %s", vd->toChars(), it->toChars());
const unsigned f_begin = it->first->offset;
const unsigned f_end = f_begin + it->first->type->size();
if (vd->offset < f_end && (vd->offset + vd->type->size()) > f_begin)
{
error(ini->loc, "initializer for %s overlaps previous initialization of %s",
vd->toChars(), it->first->toChars());
}
}
IF_LOG Logger::println("Explicit initializer: %s @+%u", vd->toChars(), vd->offset);
LOG_SCOPE;
data[idx].first = vd;
data[idx].second = get_default_initializer(vd, ini);
initConsts[vd] = DtoConstInitializer(ini->loc, vd->type, ini);
}
// stop if there were errors
if (global.errors)
{
fatal();
}
// fill in implicit initializers
n = data.size();
llvm::Constant* init = createInitializerConstant(initConsts, si->ltype);
si->ltype = static_cast<llvm::StructType*>(init->getType());
return init;
}
//////////////////////////////////////////////////////////////////////////////
typedef std::pair<VarDeclaration*, llvm::Constant*> VarInitConst;
static bool struct_init_data_sort(const VarInitConst& a, const VarInitConst& b)
{
return (a.first && b.first)
? a.first->offset < b.first->offset
: false;
}
// helper function that returns the static default initializer of a variable
LLConstant* get_default_initializer(VarDeclaration* vd, Initializer* init)
{
if (init)
{
return DtoConstInitializer(init->loc, vd->type, init);
}
else if (vd->init)
{
return DtoConstInitializer(vd->init->loc, vd->type, vd->init);
}
else
{
return DtoConstExpInit(vd->loc, vd->type, vd->type->defaultInit(vd->loc));
}
}
// return a constant array of type arrTypeD initialized with a constant value, or that constant value
static llvm::Constant* FillSArrayDims(Type* arrTypeD, llvm::Constant* init)
{
// Check whether we actually need to expand anything.
// KLUDGE: We don't have the initializer type here, so we can only check
// the size without doing an expensive recursive D <-> LLVM type comparison.
// The better way to solve this would be to just fix the initializer
// codegen in any place where a scalar initializer might still be generated.
if (gDataLayout->getTypeStoreSize(init->getType()) >= arrTypeD->size())
return init;
if (arrTypeD->ty == Tsarray)
{
init = FillSArrayDims(arrTypeD->nextOf(), init);
size_t dim = static_cast<TypeSArray*>(arrTypeD)->dim->toUInteger();
llvm::ArrayType* arrty = llvm::ArrayType::get(init->getType(), dim);
return llvm::ConstantArray::get(arrty,
std::vector<llvm::Constant*>(dim, init));
}
return init;
}
llvm::Constant* IrAggr::createInitializerConstant(
const VarInitMap& explicitInitializers,
llvm::StructType* initializerType)
{
IF_LOG Logger::println("Creating initializer constant for %s", aggrdecl->toChars());
llvm::SmallVector<llvm::Constant*, 16> constants;
unsigned offset = 0;
if (type->ty == Tclass)
{
// add vtbl
constants.push_back(getVtblSymbol());
// add monitor
constants.push_back(getNullValue(DtoType(Type::tvoid->pointerTo())));
// we start right after the vtbl and monitor
offset = PTRSIZE * 2;
}
addFieldInitializers(constants, explicitInitializers, aggrdecl, offset);
// tail padding?
const size_t structsize = type->size();
if (offset < structsize)
{
size_t diff = structsize - offset;
IF_LOG Logger::println("adding %zu bytes zero padding", diff);
add_zeros(constants, diff);
}
// get initializer type
if (!initializerType || initializerType->isOpaque())
{
llvm::SmallVector<llvm::Constant*, 16>::iterator itr, end = constants.end();
llvm::SmallVector<llvm::Type*, 16> types;
types.reserve(constants.size());
for (itr = constants.begin(); itr != end; ++itr)
types.push_back((*itr)->getType());
if (!initializerType)
initializerType = LLStructType::get(gIR->context(), types, packed);
else
initializerType->setBody(types, packed);
}
// build constant
assert(!constants.empty());
llvm::Constant* c = LLConstantStruct::get(initializerType, constants);
IF_LOG Logger::cout() << "final initializer: " << *c << std::endl;
return c;
}
void IrAggr::addFieldInitializers(
llvm::SmallVectorImpl<llvm::Constant*>& constants,
const VarInitMap& explicitInitializers,
AggregateDeclaration* decl,
unsigned& offset)
{
if (ClassDeclaration* cd = decl->isClassDeclaration())
{
if (cd->baseClass)
{
addFieldInitializers(constants, explicitInitializers,
cd->baseClass, offset);
}
}
const bool packed = (type->ty == Tstruct)
? type->alignsize() == 1
: false;
// Build up vector with one-to-one mapping to field indices.
const size_t n = decl->fields.dim;
llvm::SmallVector<VarInitConst, 16> data(n);
// Fill in explicit initializers.
for (size_t i = 0; i < n; ++i)
{
VarDeclaration* vd = decl->fields[i];
VarInitMap::const_iterator expl = explicitInitializers.find(vd);
if (expl != explicitInitializers.end())
data[i] = *expl;
}
// Fill in implicit initializers
for (size_t i = 0; i < n; i++)
{
VarDeclaration* vd = data[i].first;
if (vd)
continue;
if (data[i].first) continue;
vd = static_cast<VarDeclaration*>(aggrdecl->fields.data[i]);
VarDeclaration* vd = decl->fields[i];
unsigned vd_begin = vd->offset;
unsigned vd_end = vd_begin + vd->type->size();
// make sure it doesn't overlap any explicit initializers.
VarDeclarationIter it(aggrdecl->fields);
bool overlaps = false;
size_t j = 0;
for (; it.more(); it.next(), j++)
if (type->ty == Tstruct)
{
if (i == j || !data[j].first)
continue;
// Only structs and unions can have overlapping fields.
for (size_t j = 0; j < n; ++j)
{
if (i == j || !data[j].first)
continue;
unsigned f_begin = it->offset;
unsigned f_end = f_begin + it->type->size();
VarDeclaration* it = decl->fields[j];
unsigned f_begin = it->offset;
unsigned f_end = f_begin + it->type->size();
if (vd_begin >= f_end || vd_end <= f_begin)
continue;
if (vd_begin >= f_end || vd_end <= f_begin)
continue;
overlaps = true;
break;
overlaps = true;
break;
}
}
// add if no overlap found
if (!overlaps)
@@ -332,14 +365,63 @@ LLConstant * IrAggr::createStructInitializer(StructInitializer * si)
}
}
// stop if there were errors
if (global.errors)
// Sort data array by offset.
// TODO: Figure out whether this is really necessary, fields should already
// be in offset order. Not having do do this would mean we could use a plain
// llvm::Constant* vector for initializers and avoid all the VarInitConst business.
std::sort(data.begin(), data.end(), struct_init_data_sort);
// build array of constants and make sure explicit zero padding is inserted when necessary.
for (size_t i = 0; i < n; i++)
{
fatal();
VarDeclaration* vd = data[i].first;
if (vd == NULL)
continue;
// get next aligned offset for this field
size_t alignedoffset = offset;
if (!packed)
{
alignedoffset = realignOffset(alignedoffset, vd->type);
}
// insert explicit padding?
if (alignedoffset < vd->offset)
{
size_t diff = vd->offset - alignedoffset;
IF_LOG Logger::println("adding %zu bytes zero padding", diff);
add_zeros(constants, diff);
}
IF_LOG Logger::println("adding field %s", vd->toChars());
constants.push_back(FillSArrayDims(vd->type, data[i].second));
offset = vd->offset + vd->type->size();
}
llvm::Constant* init =
type->irtype->isStruct()->createInitializerConstant(data, si->ltype);
si->ltype = static_cast<llvm::StructType*>(init->getType());
return init;
if (ClassDeclaration* cd = decl->isClassDeclaration())
{
// has interface vtbls?
if (cd->vtblInterfaces && cd->vtblInterfaces->dim > 0)
{
// false when it's not okay to use functions from super classes
bool newinsts = (cd == aggrdecl->isClassDeclaration());
size_t inter_idx = interfacesWithVtbls.size();
offset = (offset + PTRSIZE - 1) & ~(PTRSIZE - 1);
ArrayIter<BaseClass> it2(*cd->vtblInterfaces);
for (; !it2.done(); it2.next())
{
BaseClass* b = it2.get();
constants.push_back(getInterfaceVtbl(b, newinsts, inter_idx));
offset += PTRSIZE;
// add to the interface list
interfacesWithVtbls.push_back(b);
inter_idx++;
}
}
}
}