void LTOModule::addPotentialUndefinedSymbol(GlobalValue* decl, Mangler &mangler)
{
const char* name = mangler.getValueName(decl).c_str();
// ignore all llvm.* symbols
if ( strncmp(name, "llvm.", 5) != 0 ) {
_undefines[name] = 1;
}
}
void LTOModule::addDefinedSymbol(GlobalValue* def, Mangler &mangler,
bool isFunction)
{
// string is owned by _defines
const char* symbolName = ::strdup(mangler.getValueName(def).c_str());
// set alignment part log2() can have rounding errors
uint32_t align = def->getAlignment();
uint32_t attr = align ? CountTrailingZeros_32(def->getAlignment()) : 0;
// set permissions part
if ( isFunction )
attr |= LTO_SYMBOL_PERMISSIONS_CODE;
else {
GlobalVariable* gv = dyn_cast<GlobalVariable>(def);
if ( (gv != NULL) && gv->isConstant() )
attr |= LTO_SYMBOL_PERMISSIONS_RODATA;
else
attr |= LTO_SYMBOL_PERMISSIONS_DATA;
}
// set definition part
if ( def->hasWeakLinkage() || def->hasLinkOnceLinkage() ) {
// lvm bitcode does not differenciate between weak def data
// and tentative definitions!
// HACK HACK HACK
// C++ does not use tentative definitions, but does use weak symbols
// so guess that anything that looks like a C++ symbol is weak and others
// are tentative definitions
if ( (strncmp(symbolName, "__Z", 3) == 0) )
attr |= LTO_SYMBOL_DEFINITION_WEAK;
else {
attr |= LTO_SYMBOL_DEFINITION_TENTATIVE;
}
}
else {
attr |= LTO_SYMBOL_DEFINITION_REGULAR;
}
// set scope part
if ( def->hasHiddenVisibility() )
attr |= LTO_SYMBOL_SCOPE_HIDDEN;
else if ( def->hasExternalLinkage() || def->hasWeakLinkage() )
attr |= LTO_SYMBOL_SCOPE_DEFAULT;
else
attr |= LTO_SYMBOL_SCOPE_INTERNAL;
// add to table of symbols
NameAndAttributes info;
info.name = symbolName;
info.attributes = (lto_symbol_attributes)attr;
_symbols.push_back(info);
_defines[info.name] = 1;
}
// Find exeternal symbols referenced by VALUE. This is a recursive function.
static void
findExternalRefs(Value *value, std::set<std::string> &references,
Mangler &mangler) {
if (GlobalValue *gv = dyn_cast<GlobalValue>(value)) {
LTOLinkageTypes lt = getLTOLinkageType(gv);
if (lt != LTOInternalLinkage && strncmp (gv->getName().c_str(), "llvm.", 5))
references.insert(mangler.getValueName(gv));
}
// GlobalValue, even with InternalLinkage type, may have operands with
// ExternalLinkage type. Do not ignore these operands.
if (Constant *c = dyn_cast<Constant>(value))
// Handle ConstantExpr, ConstantStruct, ConstantArry etc..
for (unsigned i = 0, e = c->getNumOperands(); i != e; ++i)
findExternalRefs(c->getOperand(i), references, mangler);
}
