/// Create - create a fragment reference for a given fragment.
///
/// @param pFrag - the given fragment
/// @param pOffset - the offset, can be larger than the fragment, but can not
/// be larger than the section size.
/// @return if the offset is legal, return the fragment reference. Otherwise,
/// return NULL.
FragmentRef* FragmentRef::Create(Fragment& pFrag, uint64_t pOffset) {
int64_t offset = pOffset;
Fragment* frag = &pFrag;
while (frag != NULL) {
offset -= frag->size();
if (offset <= 0)
break;
frag = frag->getNextNode();
}
if ((frag != NULL) && (frag->size() != 0)) {
if (offset == 0)
frag = frag->getNextNode();
else
offset += frag->size();
}
if (frag == NULL)
return Null();
FragmentRef* result = g_FragRefFactory->allocate();
new (result) FragmentRef(*frag, offset);
return result;
}
BranchIsland::BranchIsland(Fragment& pEntryFrag,
size_t pMaxSize,
size_t pIndex)
: m_Entry(pEntryFrag),
m_pExit(pEntryFrag.getNextNode()),
m_pRear(NULL),
m_MaxSize(pMaxSize),
m_Name("island-")
{
// island name
std::ostringstream index;
index << pIndex;
m_Name.append(index.str());
}
/// produce - produce a island for the given fragment
/// @param pFragment - the fragment needs a branch island
BranchIsland* BranchIslandFactory::produce(Fragment& pFragment)
{
assert(NULL == find(pFragment));
uint64_t island_offset = pFragment.getOffset() + m_MaxBranchRange -
(pFragment.getOffset() % m_MaxBranchRange);
// find out the last fragment whose offset is smaller than the calculated
// offset of the island
Fragment* frag = &pFragment;
while (NULL != frag->getNextNode()) {
if (frag->getNextNode()->getOffset() > island_offset)
break;
frag = frag->getNextNode();
}
// fall back one step if needed
if (NULL != frag &&
(frag->getOffset() + frag->size()) > island_offset)
frag = frag->getPrevNode();
// check not to break the alignment constraint in the target section
// (i.e., do not insert the island after a Alignment fragment)
while (NULL != frag &&
Fragment::Alignment == frag->getKind()) {
frag = frag->getPrevNode();
}
// can not find an entry fragment to bridge the island
if (NULL == frag)
return NULL;
BranchIsland *island = allocate();
new (island) BranchIsland(*frag, // entry fragment to the island
m_MaxIslandSize, // the max size of the island
size() - 1u); // index in the island factory
return island;
}
bool MipsGNULDBackend::doRelax(Module& pModule,
IRBuilder& pBuilder,
bool& pFinished) {
assert(getStubFactory() != NULL && getBRIslandFactory() != NULL);
bool isRelaxed = false;
for (Module::obj_iterator input = pModule.obj_begin();
input != pModule.obj_end();
++input) {
LDContext* context = (*input)->context();
for (LDContext::sect_iterator rs = context->relocSectBegin();
rs != context->relocSectEnd();
++rs) {
LDSection* sec = *rs;
if (LDFileFormat::Ignore == sec->kind() || !sec->hasRelocData())
continue;
for (RelocData::iterator reloc = sec->getRelocData()->begin();
reloc != sec->getRelocData()->end();
++reloc) {
if (llvm::ELF::R_MIPS_26 != reloc->type())
continue;
if (relaxRelocation(pBuilder, *llvm::cast<Relocation>(reloc)))
isRelaxed = true;
}
}
}
SectionData* textData = getOutputFormat()->getText().getSectionData();
// find the first fragment w/ invalid offset due to stub insertion
Fragment* invalid = NULL;
pFinished = true;
for (BranchIslandFactory::iterator ii = getBRIslandFactory()->begin(),
ie = getBRIslandFactory()->end();
ii != ie;
++ii) {
BranchIsland& island = *ii;
if (island.end() == textData->end())
break;
Fragment* exit = island.end();
if ((island.offset() + island.size()) > exit->getOffset()) {
invalid = exit;
pFinished = false;
break;
}
}
// reset the offset of invalid fragments
while (invalid != NULL) {
invalid->setOffset(invalid->getPrevNode()->getOffset() +
invalid->getPrevNode()->size());
invalid = invalid->getNextNode();
}
// reset the size of .text
if (isRelaxed)
getOutputFormat()->getText().setSize(textData->back().getOffset() +
textData->back().size());
return isRelaxed;
}
bool AArch64GNULDBackend::doRelax(Module& pModule,
IRBuilder& pBuilder,
bool& pFinished) {
assert(getStubFactory() != NULL && getBRIslandFactory() != NULL);
// Number of new stubs added
size_t num_new_stubs = 0;
// String lengh to hold new stub symbols
size_t stubs_strlen = 0;
if (config().targets().fixCA53Erratum835769() ||
config().targets().fixCA53Erratum843419()) {
scanErrata(pModule, pBuilder, num_new_stubs, stubs_strlen);
}
ELFFileFormat* file_format = getOutputFormat();
// check branch relocs and create the related stubs if needed
Module::obj_iterator input, inEnd = pModule.obj_end();
for (input = pModule.obj_begin(); input != inEnd; ++input) {
LDContext::sect_iterator rs, rsEnd = (*input)->context()->relocSectEnd();
for (rs = (*input)->context()->relocSectBegin(); rs != rsEnd; ++rs) {
if (LDFileFormat::Ignore == (*rs)->kind() || !(*rs)->hasRelocData())
continue;
RelocData::iterator reloc, rEnd = (*rs)->getRelocData()->end();
for (reloc = (*rs)->getRelocData()->begin(); reloc != rEnd; ++reloc) {
Relocation* relocation = llvm::cast<Relocation>(reloc);
switch (relocation->type()) {
case llvm::ELF::R_AARCH64_CALL26:
case llvm::ELF::R_AARCH64_JUMP26: {
// calculate the possible symbol value
uint64_t sym_value = 0x0;
LDSymbol* symbol = relocation->symInfo()->outSymbol();
if (symbol->hasFragRef()) {
uint64_t value = symbol->fragRef()->getOutputOffset();
uint64_t addr =
symbol->fragRef()->frag()->getParent()->getSection().addr();
sym_value = addr + value;
}
if ((relocation->symInfo()->reserved() &
AArch64Relocator::ReservePLT) != 0x0) {
// FIXME: we need to find out the address of the specific plt
// entry
assert(file_format->hasPLT());
sym_value = file_format->getPLT().addr();
}
Stub* stub = getStubFactory()->create(*relocation, // relocation
sym_value, // symbol value
pBuilder,
*getBRIslandFactory());
if (stub != NULL) {
// a stub symbol should be local
assert(stub->symInfo() != NULL && stub->symInfo()->isLocal());
// reset the branch target of the reloc to this stub instead
relocation->setSymInfo(stub->symInfo());
++num_new_stubs;
stubs_strlen += stub->symInfo()->nameSize() + 1;
}
break;
}
default: {
break;
}
} // end of switch
} // for all relocations
} // for all relocation section
} // for all inputs
// Find the first fragment w/ invalid offset due to stub insertion.
std::vector<Fragment*> invalid_frags;
pFinished = true;
for (BranchIslandFactory::iterator island = getBRIslandFactory()->begin(),
island_end = getBRIslandFactory()->end();
island != island_end;
++island) {
if ((*island).size() > stubGroupSize()) {
error(diag::err_no_space_to_place_stubs) << stubGroupSize();
return false;
}
if ((*island).numOfStubs() == 0) {
continue;
}
Fragment* exit = &*(*island).end();
if (exit == (*island).begin()->getParent()->end()) {
continue;
}
if (((*island).offset() + (*island).size()) > exit->getOffset()) {
if (invalid_frags.empty() ||
(invalid_frags.back()->getParent() != (*island).getParent())) {
invalid_frags.push_back(exit);
pFinished = false;
}
continue;
}
}
// Reset the offset of invalid fragments.
for (auto it = invalid_frags.begin(), ie = invalid_frags.end(); it != ie;
++it) {
Fragment* invalid = *it;
while (invalid != NULL) {
invalid->setOffset(invalid->getPrevNode()->getOffset() +
invalid->getPrevNode()->size());
invalid = invalid->getNextNode();
}
}
// Fix up the size of .symtab, .strtab, and TEXT sections
if (num_new_stubs == 0) {
return false;
} else {
switch (config().options().getStripSymbolMode()) {
case GeneralOptions::StripSymbolMode::StripAllSymbols:
case GeneralOptions::StripSymbolMode::StripLocals:
break;
default: {
LDSection& symtab = file_format->getSymTab();
LDSection& strtab = file_format->getStrTab();
symtab.setSize(symtab.size() +
sizeof(llvm::ELF::Elf64_Sym) * num_new_stubs);
symtab.setInfo(symtab.getInfo() + num_new_stubs);
strtab.setSize(strtab.size() + stubs_strlen);
}
} // switch (config().options().getStripSymbolMode())
SectionData* prev = NULL;
for (BranchIslandFactory::iterator island = getBRIslandFactory()->begin(),
island_end = getBRIslandFactory()->end();
island != island_end;
++island) {
SectionData* sd = (*island).begin()->getParent();
if ((*island).numOfStubs() != 0) {
if (sd != prev) {
sd->getSection().setSize(sd->back().getOffset() + sd->back().size());
}
}
prev = sd;
}
return true;
} // if (num_new_stubs == 0)
}
bool HexagonLDBackend::doRelax(Module& pModule, IRBuilder& pBuilder,
bool& pFinished)
{
assert(NULL != getStubFactory() && NULL != getBRIslandFactory());
bool isRelaxed = false;
ELFFileFormat* file_format = getOutputFormat();
// check branch relocs and create the related stubs if needed
Module::obj_iterator input, inEnd = pModule.obj_end();
for (input = pModule.obj_begin(); input != inEnd; ++input) {
LDContext::sect_iterator rs, rsEnd = (*input)->context()->relocSectEnd();
for (rs = (*input)->context()->relocSectBegin(); rs != rsEnd; ++rs) {
if (LDFileFormat::Ignore == (*rs)->kind() || !(*rs)->hasRelocData())
continue;
RelocData::iterator reloc, rEnd = (*rs)->getRelocData()->end();
for (reloc = (*rs)->getRelocData()->begin(); reloc != rEnd; ++reloc) {
switch (reloc->type()) {
case llvm::ELF::R_HEX_B22_PCREL:
case llvm::ELF::R_HEX_B15_PCREL:
case llvm::ELF::R_HEX_B7_PCREL:
case llvm::ELF::R_HEX_B13_PCREL:
case llvm::ELF::R_HEX_B9_PCREL: {
Relocation* relocation = llvm::cast<Relocation>(reloc);
uint64_t sym_value = 0x0;
LDSymbol* symbol = relocation->symInfo()->outSymbol();
if (symbol->hasFragRef()) {
uint64_t value = symbol->fragRef()->getOutputOffset();
uint64_t addr =
symbol->fragRef()->frag()->getParent()->getSection().addr();
sym_value = addr + value;
}
Stub* stub = getStubFactory()->create(*relocation, // relocation
sym_value, //symbol value
pBuilder,
*getBRIslandFactory());
if (NULL != stub) {
assert(NULL != stub->symInfo());
// increase the size of .symtab and .strtab
LDSection& symtab = file_format->getSymTab();
LDSection& strtab = file_format->getStrTab();
symtab.setSize(symtab.size() + sizeof(llvm::ELF::Elf32_Sym));
strtab.setSize(strtab.size() + stub->symInfo()->nameSize() + 1);
isRelaxed = true;
}
}
break;
default:
break;
}
}
}
}
// find the first fragment w/ invalid offset due to stub insertion
Fragment* invalid = NULL;
pFinished = true;
for (BranchIslandFactory::iterator island = getBRIslandFactory()->begin(),
island_end = getBRIslandFactory()->end(); island != island_end; ++island)
{
if ((*island).end() == file_format->getText().getSectionData()->end())
break;
Fragment* exit = (*island).end();
if (((*island).offset() + (*island).size()) > exit->getOffset()) {
invalid = exit;
pFinished = false;
break;
}
}
// reset the offset of invalid fragments
while (NULL != invalid) {
invalid->setOffset(invalid->getPrevNode()->getOffset() +
invalid->getPrevNode()->size());
invalid = invalid->getNextNode();
}
// reset the size of .text
if (isRelaxed) {
file_format->getText().setSize(
file_format->getText().getSectionData()->back().getOffset() +
file_format->getText().getSectionData()->back().size());
}
return isRelaxed;
}
/// doRelax
bool
ARMGNULDBackend::doRelax(Module& pModule, IRBuilder& pBuilder, bool& pFinished)
{
assert(NULL != getStubFactory() && NULL != getBRIslandFactory());
bool isRelaxed = false;
ELFFileFormat* file_format = getOutputFormat();
// check branch relocs and create the related stubs if needed
Module::obj_iterator input, inEnd = pModule.obj_end();
for (input = pModule.obj_begin(); input != inEnd; ++input) {
LDContext::sect_iterator rs, rsEnd = (*input)->context()->relocSectEnd();
for (rs = (*input)->context()->relocSectBegin(); rs != rsEnd; ++rs) {
if (LDFileFormat::Ignore == (*rs)->kind() || !(*rs)->hasRelocData())
continue;
RelocData::iterator reloc, rEnd = (*rs)->getRelocData()->end();
for (reloc = (*rs)->getRelocData()->begin(); reloc != rEnd; ++reloc) {
Relocation* relocation = llvm::cast<Relocation>(reloc);
switch (relocation->type()) {
case llvm::ELF::R_ARM_PC24:
case llvm::ELF::R_ARM_CALL:
case llvm::ELF::R_ARM_JUMP24:
case llvm::ELF::R_ARM_PLT32:
case llvm::ELF::R_ARM_THM_CALL:
case llvm::ELF::R_ARM_THM_XPC22:
case llvm::ELF::R_ARM_THM_JUMP24:
case llvm::ELF::R_ARM_THM_JUMP19: {
// calculate the possible symbol value
uint64_t sym_value = 0x0;
LDSymbol* symbol = relocation->symInfo()->outSymbol();
if (symbol->hasFragRef()) {
uint64_t value = symbol->fragRef()->getOutputOffset();
uint64_t addr =
symbol->fragRef()->frag()->getParent()->getSection().addr();
sym_value = addr + value;
}
if (relocation->symInfo()->isGlobal() &&
(relocation->symInfo()->reserved() & ARMRelocator::ReservePLT) != 0x0) {
// FIXME: we need to find out the address of the specific plt entry
assert(file_format->hasPLT());
sym_value = file_format->getPLT().addr();
}
Stub* stub = getStubFactory()->create(*relocation, // relocation
sym_value, // symbol value
pBuilder,
*getBRIslandFactory());
if (NULL != stub) {
switch (config().options().getStripSymbolMode()) {
case GeneralOptions::StripAllSymbols:
case GeneralOptions::StripLocals:
break;
default: {
// a stub symbol should be local
assert(NULL != stub->symInfo() && stub->symInfo()->isLocal());
LDSection& symtab = file_format->getSymTab();
LDSection& strtab = file_format->getStrTab();
// increase the size of .symtab and .strtab if needed
if (config().targets().is32Bits())
symtab.setSize(symtab.size() + sizeof(llvm::ELF::Elf32_Sym));
else
symtab.setSize(symtab.size() + sizeof(llvm::ELF::Elf64_Sym));
symtab.setInfo(symtab.getInfo() + 1);
strtab.setSize(strtab.size() + stub->symInfo()->nameSize() + 1);
}
} // end of switch
isRelaxed = true;
}
break;
}
case llvm::ELF::R_ARM_V4BX:
/* FIXME: bypass R_ARM_V4BX relocation now */
break;
default:
break;
} // end of switch
} // for all relocations
} // for all relocation section
} // for all inputs
// find the first fragment w/ invalid offset due to stub insertion
Fragment* invalid = NULL;
pFinished = true;
for (BranchIslandFactory::iterator island = getBRIslandFactory()->begin(),
island_end = getBRIslandFactory()->end(); island != island_end; ++island) {
if ((*island).end() == file_format->getText().getSectionData()->end())
break;
Fragment* exit = (*island).end();
if (((*island).offset() + (*island).size()) > exit->getOffset()) {
invalid = exit;
pFinished = false;
break;
}
}
// reset the offset of invalid fragments
while (NULL != invalid) {
invalid->setOffset(invalid->getPrevNode()->getOffset() +
invalid->getPrevNode()->size());
invalid = invalid->getNextNode();
}
// reset the size of .text
if (isRelaxed) {
file_format->getText().setSize(
file_format->getText().getSectionData()->back().getOffset() +
file_format->getText().getSectionData()->back().size());
}
return isRelaxed;
}
