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//===- ObjectBuilder.cpp --------------------------------------------------===//
//
// The MCLinker Project
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "mcld/Object/ObjectBuilder.h"
#include "mcld/IRBuilder.h"
#include "mcld/LinkerScript.h"
#include "mcld/Module.h"
#include "mcld/Fragment/AlignFragment.h"
#include "mcld/Fragment/FillFragment.h"
#include "mcld/Fragment/NullFragment.h"
#include "mcld/LD/DebugString.h"
#include "mcld/LD/EhFrame.h"
#include "mcld/LD/LDSection.h"
#include "mcld/LD/SectionData.h"
#include "mcld/Object/SectionMap.h"
#include <llvm/Support/Casting.h>
namespace mcld {
//===----------------------------------------------------------------------===//
// ObjectBuilder
//===----------------------------------------------------------------------===//
ObjectBuilder::ObjectBuilder(Module& pTheModule) : m_Module(pTheModule) {
}
/// CreateSection - create an output section.
LDSection* ObjectBuilder::CreateSection(const std::string& pName,
LDFileFormat::Kind pKind,
uint32_t pType,
uint32_t pFlag,
uint32_t pAlign) {
// try to get one from output LDSection
SectionMap::const_mapping pair =
m_Module.getScript().sectionMap().find("*", pName);
std::string output_name = (pair.first == NULL) ? pName : pair.first->name();
LDSection* output_sect = m_Module.getSection(output_name);
if (output_sect == NULL) {
output_sect = LDSection::Create(pName, pKind, pType, pFlag);
output_sect->setAlign(pAlign);
m_Module.getSectionTable().push_back(output_sect);
}
return output_sect;
}
/// MergeSection - merge the pInput section to the pOutput section
LDSection* ObjectBuilder::MergeSection(const Input& pInputFile,
LDSection& pInputSection) {
SectionMap::mapping pair = m_Module.getScript().sectionMap().find(
pInputFile.path().native(), pInputSection.name());
if (pair.first != NULL && pair.first->isDiscard()) {
pInputSection.setKind(LDFileFormat::Ignore);
return NULL;
}
std::string output_name =
(pair.first == NULL) ? pInputSection.name() : pair.first->name();
LDSection* target = m_Module.getSection(output_name);
if (target == NULL) {
target = LDSection::Create(output_name,
pInputSection.kind(),
pInputSection.type(),
pInputSection.flag());
target->setAlign(pInputSection.align());
m_Module.getSectionTable().push_back(target);
}
switch (target->kind()) {
case LDFileFormat::EhFrame: {
EhFrame* eh_frame = NULL;
if (target->hasEhFrame())
eh_frame = target->getEhFrame();
else
eh_frame = IRBuilder::CreateEhFrame(*target);
eh_frame->merge(pInputFile, *pInputSection.getEhFrame());
UpdateSectionAlign(*target, pInputSection);
return target;
}
case LDFileFormat::DebugString: {
DebugString* debug_str = NULL;
if (target->hasDebugString())
debug_str = target->getDebugString();
else
debug_str = IRBuilder::CreateDebugString(*target);
debug_str->merge(pInputSection);
UpdateSectionAlign(*target, pInputSection);
return target;
}
default: {
if (!target->hasSectionData())
IRBuilder::CreateSectionData(*target);
SectionData* data = NULL;
if (pair.first != NULL) {
assert(pair.second != NULL);
data = pair.second->getSection()->getSectionData();
// force input alignment from ldscript if any
if (pair.first->prolog().hasSubAlign()) {
pInputSection.setAlign(pair.second->getSection()->align());
}
} else {
// orphan section
data = target->getSectionData();
}
if (MoveSectionData(*pInputSection.getSectionData(), *data)) {
UpdateSectionAlign(*target, pInputSection);
return target;
}
return NULL;
}
}
return target;
}
/// MoveSectionData - move the fragments of pTO section data to pTo
bool ObjectBuilder::MoveSectionData(SectionData& pFrom, SectionData& pTo) {
assert(&pFrom != &pTo && "Cannot move section data to itself!");
uint64_t offset = pTo.getSection().size();
AlignFragment* align = NULL;
if (pFrom.getSection().align() > 1) {
// if the align constraint is larger than 1, append an alignment
unsigned int alignment = pFrom.getSection().align();
align = new AlignFragment(/*alignment*/alignment,
/*the filled value*/0x0,
/*the size of filled value*/1u,
/*max bytes to emit*/alignment - 1);
align->setOffset(offset);
align->setParent(&pTo);
pTo.getFragmentList().push_back(align);
offset += align->size();
}
// move fragments from pFrom to pTO
SectionData::FragmentListType& from_list = pFrom.getFragmentList();
SectionData::FragmentListType& to_list = pTo.getFragmentList();
SectionData::FragmentListType::iterator frag, fragEnd = from_list.end();
for (frag = from_list.begin(); frag != fragEnd; ++frag) {
frag->setParent(&pTo);
frag->setOffset(offset);
offset += frag->size();
}
to_list.splice(to_list.end(), from_list);
// set up pTo's header
pTo.getSection().setSize(offset);
return true;
}
/// UpdateSectionAlign - update alignment for input section
void ObjectBuilder::UpdateSectionAlign(LDSection& pTo, const LDSection& pFrom) {
if (pFrom.align() > pTo.align())
pTo.setAlign(pFrom.align());
}
/// UpdateSectionAlign - update alignment for input section
void ObjectBuilder::UpdateSectionAlign(LDSection& pSection,
uint32_t pAlignConstraint) {
if (pSection.align() < pAlignConstraint)
pSection.setAlign(pAlignConstraint);
}
/// AppendFragment - To append pFrag to the given SectionData pSD.
uint64_t ObjectBuilder::AppendFragment(Fragment& pFrag,
SectionData& pSD,
uint32_t pAlignConstraint) {
// get initial offset.
uint64_t offset = 0;
if (!pSD.empty())
offset = pSD.back().getOffset() + pSD.back().size();
AlignFragment* align = NULL;
if (pAlignConstraint > 1) {
// if the align constraint is larger than 1, append an alignment
align = new AlignFragment(/*alignment*/pAlignConstraint,
/*the filled value*/0x0,
/*the size of filled value*/1u,
/*max bytes to emit*/pAlignConstraint - 1);
align->setOffset(offset);
align->setParent(&pSD);
pSD.getFragmentList().push_back(align);
offset += align->size();
}
// append the fragment
pFrag.setParent(&pSD);
pFrag.setOffset(offset);
pSD.getFragmentList().push_back(&pFrag);
// append the null fragment
offset += pFrag.size();
NullFragment* null = new NullFragment(&pSD);
null->setOffset(offset);
if (align != NULL)
return align->size() + pFrag.size();
else
return pFrag.size();
}
} // namespace mcld