void Stub::applyFixup(Relocation& pSrcReloc,
IRBuilder& pBuilder,
BranchIsland& pIsland) {
// build a name for stub symbol
std::string sym_name("__");
sym_name.append(pSrcReloc.symInfo()->name())
.append("_")
.append(name())
.append("@")
.append(pIsland.name());
// create LDSymbol for the stub
LDSymbol* symbol =
pBuilder.AddSymbol<IRBuilder::Force, IRBuilder::Unresolve>(
sym_name,
ResolveInfo::Function,
ResolveInfo::Define,
ResolveInfo::Local,
size(),
initSymValue(),
FragmentRef::Create(*this, initSymValue()),
ResolveInfo::Default);
setSymInfo(symbol->resolveInfo());
// add relocations of this stub (i.e., set the branch target of the stub)
for (fixup_iterator it = fixup_begin(), ie = fixup_end(); it != ie; ++it) {
Relocation* reloc =
Relocation::Create((*it)->type(),
*(FragmentRef::Create(*this, (*it)->offset())),
(*it)->addend());
reloc->setSymInfo(pSrcReloc.symInfo());
pIsland.addRelocation(*reloc);
}
}
void GarbageCollection::getEntrySections(SectionVecTy& pEntry)
{
// all the KEEP sections defined in ldscript are entries, traverse all the
// input sections and check the SectionMap to find the KEEP sections
Module::obj_iterator obj, objEnd = m_Module.obj_end();
SectionMap& sect_map = m_Module.getScript().sectionMap();
for (obj = m_Module.obj_begin(); obj != objEnd; ++obj) {
const std::string input_name = (*obj)->name();
LDContext::sect_iterator sect, sectEnd = (*obj)->context()->sectEnd();
for (sect = (*obj)->context()->sectBegin(); sect != sectEnd; ++sect) {
LDSection* section = *sect;
if (LDFileFormat::Regular != section->kind() &&
LDFileFormat::BSS != section->kind())
continue;
SectionMap::Input* sm_input =
sect_map.find(input_name, section->name()).second;
if ((sm_input != NULL) && (InputSectDesc::Keep == sm_input->policy()))
pEntry.push_back(section);
}
}
// get the sections those the entry symbols defined in
Module::SymbolTable& sym_tab = m_Module.getSymbolTable();
if (LinkerConfig::Exec == m_Config.codeGenType()) {
assert(NULL != m_pEntry);
pEntry.push_back(&m_pEntry->fragRef()->frag()->getParent()->getSection());
}
else {
// when building shared objects, the global define symbols are entries
SymbolCategory::iterator it, end = sym_tab.regularEnd();
for (it = sym_tab.dynamicBegin(); it != end; ++it) {
LDSymbol* sym = *it;
if (!sym->resolveInfo()->isDefine() || !sym->hasFragRef())
continue;
// only the target symbols defined in the concerned sections can make
// the reference
const LDSection* sect =
&sym->fragRef()->frag()->getParent()->getSection();
if (sect->kind() != LDFileFormat::Regular &&
sect->kind() != LDFileFormat::BSS)
continue;
pEntry.push_back(sect);
}
}
}
/// create - create a stub if needed, otherwise return NULL
Stub* StubFactory::create(Relocation& pReloc,
uint64_t pTargetSymValue,
IRBuilder& pBuilder,
BranchIslandFactory& pBRIslandFactory)
{
// find if there is a prototype stub for the input relocation
Stub* prototype = findPrototype(pReloc,
pReloc.place(),
pTargetSymValue);
if (NULL != prototype) {
// find the island for the input relocation
BranchIsland* island = pBRIslandFactory.find(*(pReloc.targetRef().frag()));
if (NULL == island) {
island = pBRIslandFactory.produce(*(pReloc.targetRef().frag()));
}
// find if there is such a stub in the island already
assert(NULL != island);
Stub* stub = island->findStub(prototype, pReloc);
if (NULL != stub) {
// reset the branch target to the stub instead!
pReloc.setSymInfo(stub->symInfo());
}
else {
// create a stub from the prototype
stub = prototype->clone();
// build a name for stub symbol
std::string name("__");
name.append(pReloc.symInfo()->name());
name.append("_");
name.append(stub->name());
name.append("@");
name.append(island->name());
// create LDSymbol for the stub
LDSymbol* symbol =
pBuilder.AddSymbol<IRBuilder::Force, IRBuilder::Resolve>(
name,
ResolveInfo::Function,
ResolveInfo::Define,
ResolveInfo::Local,
stub->size(), // size
stub->initSymValue(), // value
FragmentRef::Create(*stub, stub->initSymValue()),
ResolveInfo::Default);
stub->setSymInfo(symbol->resolveInfo());
// add relocations of this stub (i.e., set the branch target of the stub)
for (Stub::fixup_iterator it = stub->fixup_begin(),
ie = stub->fixup_end(); it != ie; ++it) {
Relocation* reloc = Relocation::Create((*it)->type(),
*(FragmentRef::Create(*stub, (*it)->offset())),
(*it)->addend());
reloc->setSymInfo(pReloc.symInfo());
island->addRelocation(*reloc);
}
// add stub to the branch island
island->addStub(prototype, pReloc, *stub);
// reset the branch target of the input reloc to this stub instead!
pReloc.setSymInfo(stub->symInfo());
return stub;
}
}
return NULL;
}
/// create - create a stub if needed, otherwise return NULL
Stub* StubFactory::create(Relocation& pReloc,
uint64_t pTargetSymValue,
IRBuilder& pBuilder,
BranchIslandFactory& pBRIslandFactory) {
// find if there is a prototype stub for the input relocation
Stub* stub = NULL;
Stub* prototype = findPrototype(pReloc, pReloc.place(), pTargetSymValue);
if (prototype != NULL) {
const Fragment* frag = pReloc.targetRef().frag();
// find the islands for the input relocation
std::pair<BranchIsland*, BranchIsland*> islands =
pBRIslandFactory.getIslands(*frag);
if (islands.first == NULL) {
// early exit if we can not find the forward island.
return NULL;
}
// find if there is such a stub in the backward island first.
if (islands.second != NULL) {
stub = islands.second->findStub(prototype, pReloc);
}
if (stub != NULL) {
// reset the branch target to the stub instead!
pReloc.setSymInfo(stub->symInfo());
} else {
// find if there is such a stub in the forward island.
stub = islands.first->findStub(prototype, pReloc);
if (stub != NULL) {
// reset the branch target to the stub instead!
pReloc.setSymInfo(stub->symInfo());
} else {
// create a stub from the prototype
stub = prototype->clone();
// build a name for stub symbol
std::string name("__");
name.append(pReloc.symInfo()->name())
.append("_")
.append(stub->name())
.append("@")
.append(islands.first->name());
// create LDSymbol for the stub
LDSymbol* symbol =
pBuilder.AddSymbol<IRBuilder::Force, IRBuilder::Unresolve>(
name,
ResolveInfo::Function,
ResolveInfo::Define,
ResolveInfo::Local,
stub->size(), // size
stub->initSymValue(), // value
FragmentRef::Create(*stub, stub->initSymValue()),
ResolveInfo::Default);
stub->setSymInfo(symbol->resolveInfo());
// add relocations of this stub (i.e., set the branch target of the
// stub)
for (Stub::fixup_iterator it = stub->fixup_begin(),
ie = stub->fixup_end();
it != ie;
++it) {
Relocation* reloc =
Relocation::Create((*it)->type(),
*(FragmentRef::Create(*stub, (*it)->offset())),
(*it)->addend());
reloc->setSymInfo(pReloc.symInfo());
islands.first->addRelocation(*reloc);
}
// add stub to the forward branch island
islands.first->addStub(prototype, pReloc, *stub);
// reset the branch target of the input reloc to this stub instead!
pReloc.setSymInfo(stub->symInfo());
}
}
}
return stub;
}
