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Fix for issue #119.

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Instead of creating individual stores to the array elements an constant
array is created and assigned to the destination memory. This is much
less IR than before. With -O it is optimized to a memset.
This commit is contained in:
kai
2013-08-18 13:32:04 +02:00
parent e24c76ec70
commit f769406216
1 changed files with 68 additions and 12 deletions
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80
gen/toir.cpp
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@@ -2876,20 +2876,76 @@ DValue* ArrayLiteralExp::toElem(IRState* p)
else
dstMem = DtoRawAlloca(llStoType, 0, "arrayliteral");
// store elements
for (size_t i=0; i<len; ++i)
// Check for const'ness
bool isAllConst = true;
for (size_t i = 0; i < len && isAllConst; ++i)
{
Expression* expr = static_cast<Expression*>(elements->data[i]);
LLValue* elemAddr;
if(dyn)
elemAddr = DtoGEPi1(dstMem, i, "tmp", p->scopebb());
else
elemAddr = DtoGEPi(dstMem,0,i,"tmp",p->scopebb());
Expression *expr = static_cast<Expression *>(elements->data[i]);
isAllConst = expr->isConst() == 1;
}
// emulate assignment
DVarValue* vv = new DVarValue(expr->type, elemAddr);
DValue* e = expr->toElem(p);
DtoAssign(loc, vv, e);
if (isAllConst)
{
// allocate room for initializers
std::vector<LLConstant *> initvals(len, NULL);
// true if array elements differ in type
bool mismatch = false;
// store elements
for (size_t i = 0; i < len; ++i)
{
Expression *expr = static_cast<Expression *>(elements->data[i]);
llvm::Constant *c = expr->toConstElem(gIR);
if (llElemType != c->getType())
mismatch = true;
initvals[i] = c;
}
LLConstant *constarr;
if (mismatch)
constarr = LLConstantStruct::getAnon(gIR->context(), initvals); // FIXME should this pack?;
else
constarr = LLConstantArray::get(LLArrayType::get(llElemType, len), initvals);
#if LDC_LLVM_VER == 301
// Simply storing the constant array triggers a problem in LLVM 3.1.
// With -O3 the statement
// void[0] sa0 = (void[0]).init;
// is compiled to
// tail call void @llvm.trap()
// which is not what we want!
// Therefore a global variable is always used.
LLGlobalVariable *gvar = new LLGlobalVariable(*gIR->module, constarr->getType(), true, LLGlobalValue::InternalLinkage, constarr, ".constarrayliteral_init");
DtoMemCpy(dstMem, gvar, DtoConstSize_t(getTypePaddedSize(constarr->getType())));
#else
// If the type pointed to by dstMem is different from the array type
// then we must assign the value to a global variable.
if (constarr->getType() != dstMem->getType()->getPointerElementType())
{
LLGlobalVariable *gvar = new LLGlobalVariable(*gIR->module, constarr->getType(), true, LLGlobalValue::InternalLinkage, constarr, ".constarrayliteral_init");
DtoMemCpy(dstMem, gvar, DtoConstSize_t(getTypePaddedSize(constarr->getType())));
}
else
DtoStore(constarr, dstMem);
#endif
}
else
{
// store elements
for (size_t i = 0; i < len; ++i)
{
Expression *expr = static_cast<Expression *>(elements->data[i]);
LLValue *elemAddr;
if(dyn)
elemAddr = DtoGEPi1(dstMem, i, "tmp", p->scopebb());
else
elemAddr = DtoGEPi(dstMem, 0, i, "tmp", p->scopebb());
// emulate assignment
DVarValue *vv = new DVarValue(expr->type, elemAddr);
DValue *e = expr->toElem(p);
DtoAssign(loc, vv, e);
}
}
// return storage directly ?