void GarbageCollection::setUpReachedSections()
{
// traverse all the input relocations to setup the reached sections
Module::obj_iterator input, inEnd = m_Module.obj_end();
for (input = m_Module.obj_begin(); input != inEnd; ++input) {
LDContext::sect_iterator rs, rsEnd = (*input)->context()->relocSectEnd();
for (rs = (*input)->context()->relocSectBegin(); rs != rsEnd; ++rs) {
// bypass the discarded relocation section
// 1. its section kind is changed to Ignore. (The target section is a
// discarded group section.)
// 2. it has no reloc data. (All symbols in the input relocs are in the
// discarded group sections)
LDSection* reloc_sect = *rs;
LDSection* apply_sect = reloc_sect->getLink();
if ((LDFileFormat::Ignore == reloc_sect->kind()) ||
(!reloc_sect->hasRelocData()))
continue;
// bypass the apply target sections which are not handled by gc (currently
// we only handle the Regular and BSS sections)
if (apply_sect->kind() != LDFileFormat::Regular &&
apply_sect->kind() != LDFileFormat::BSS)
continue;
bool add_first = false;
SectionListTy* reached_sects = NULL;
RelocData::iterator reloc_it, rEnd = reloc_sect->getRelocData()->end();
for (reloc_it = reloc_sect->getRelocData()->begin(); reloc_it != rEnd;
++reloc_it) {
Relocation* reloc = llvm::cast<Relocation>(reloc_it);
ResolveInfo* sym = reloc->symInfo();
// only the target symbols defined in the input fragments can make the
// reference
if (NULL == sym)
continue;
if (!sym->isDefine() || !sym->outSymbol()->hasFragRef())
continue;
// only the target symbols defined in the concerned sections can make
// the reference
const LDSection* target_sect =
&sym->outSymbol()->fragRef()->frag()->getParent()->getSection();
if (target_sect->kind() != LDFileFormat::Regular &&
target_sect->kind() != LDFileFormat::BSS)
continue;
// setup the reached list, if we first add the element to reached list
// of this section, create an entry in ReachedSections map
if (!add_first) {
assert(NULL == reached_sects);
reached_sects = &m_ReachedSections[apply_sect];
add_first = true;
}
reached_sects->insert(target_sect);
}
reached_sects = NULL;
add_first = false;
}
}
}
TEST_F( StaticResolverTest, SetUpBinding)
{
ResolveInfo* sym = ResolveInfo::Create("abc");
sym->setIsSymbol(true);
// ASSERT_FALSE( sym->isSymbol() );
ASSERT_TRUE( sym->isSymbol() );
ASSERT_TRUE( sym->isGlobal() );
ASSERT_FALSE( sym->isWeak() );
ASSERT_FALSE( sym->isLocal() );
ASSERT_FALSE( sym->isDefine() );
ASSERT_TRUE( sym->isUndef() );
ASSERT_FALSE( sym->isDyn() );
ASSERT_FALSE( sym->isCommon() );
ASSERT_FALSE( sym->isIndirect() );
ASSERT_TRUE( ResolveInfo::NoType == sym->type());
ASSERT_TRUE( 0 == sym->desc() );
ASSERT_TRUE( 0 == sym->binding() );
ASSERT_TRUE( 0 == sym->other() );
sym->setBinding(ResolveInfo::Global);
ASSERT_TRUE( sym->isSymbol() );
ASSERT_TRUE( sym->isGlobal() );
ASSERT_FALSE( sym->isWeak() );
ASSERT_FALSE( sym->isLocal() );
ASSERT_FALSE( sym->isDefine() );
ASSERT_TRUE( sym->isUndef() );
ASSERT_FALSE( sym->isDyn() );
ASSERT_FALSE( sym->isCommon() );
ASSERT_FALSE( sym->isIndirect() );
ASSERT_TRUE( ResolveInfo::NoType == sym->type());
ASSERT_TRUE( 0 == sym->desc() );
ASSERT_TRUE( ResolveInfo::Global == sym->binding() );
ASSERT_TRUE( 0 == sym->other() );
sym->setBinding(ResolveInfo::Weak);
ASSERT_TRUE( sym->isSymbol() );
ASSERT_FALSE( sym->isGlobal() );
ASSERT_TRUE( sym->isWeak() );
ASSERT_FALSE( sym->isLocal() );
ASSERT_FALSE( sym->isDyn() );
ASSERT_FALSE( sym->isDefine() );
ASSERT_TRUE( sym->isUndef() );
ASSERT_FALSE( sym->isCommon() );
ASSERT_FALSE( sym->isIndirect() );
ASSERT_TRUE( ResolveInfo::NoType == sym->type());
ASSERT_TRUE( 0 == sym->desc() );
ASSERT_TRUE( ResolveInfo::Weak == sym->binding() );
ASSERT_TRUE( 0 == sym->other() );
sym->setBinding(ResolveInfo::Local);
ASSERT_TRUE( sym->isSymbol() );
ASSERT_FALSE( sym->isGlobal() );
ASSERT_FALSE( sym->isWeak() );
ASSERT_TRUE( sym->isLocal() );
ASSERT_FALSE( sym->isDyn() );
ASSERT_FALSE( sym->isDefine() );
ASSERT_TRUE( sym->isUndef() );
ASSERT_FALSE( sym->isCommon() );
ASSERT_FALSE( sym->isIndirect() );
ASSERT_TRUE( ResolveInfo::NoType == sym->type());
ASSERT_TRUE( 0 == sym->desc() );
ASSERT_TRUE( ResolveInfo::Local == sym->binding() );
ASSERT_TRUE( 0 == sym->other() );
}
TEST_F( StaticResolverTest, SetUpDesc)
{
ResolveInfo* sym = ResolveInfo::Create("abc");
sym->setIsSymbol(true);
// ASSERT_FALSE( sym->isSymbol() );
ASSERT_TRUE( sym->isSymbol() );
ASSERT_TRUE( sym->isGlobal() );
ASSERT_FALSE( sym->isWeak() );
ASSERT_FALSE( sym->isLocal() );
ASSERT_FALSE( sym->isDefine() );
ASSERT_TRUE( sym->isUndef() );
ASSERT_FALSE( sym->isDyn() );
ASSERT_FALSE( sym->isCommon() );
ASSERT_FALSE( sym->isIndirect() );
ASSERT_TRUE( ResolveInfo::NoType == sym->type());
ASSERT_TRUE( 0 == sym->desc() );
ASSERT_TRUE( 0 == sym->binding() );
ASSERT_TRUE( 0 == sym->other() );
sym->setIsSymbol(false);
ASSERT_FALSE( sym->isSymbol() );
// ASSERT_TRUE( sym->isSymbol() );
ASSERT_TRUE( sym->isGlobal() );
ASSERT_FALSE( sym->isWeak() );
ASSERT_FALSE( sym->isLocal() );
ASSERT_FALSE( sym->isDefine() );
ASSERT_TRUE( sym->isUndef() );
ASSERT_FALSE( sym->isDyn() );
ASSERT_FALSE( sym->isCommon() );
ASSERT_FALSE( sym->isIndirect() );
ASSERT_TRUE( ResolveInfo::NoType == sym->type());
ASSERT_TRUE( 0 == sym->desc() );
ASSERT_TRUE( 0 == sym->binding() );
ASSERT_TRUE( 0 == sym->other() );
sym->setDesc(ResolveInfo::Define);
ASSERT_FALSE( sym->isSymbol() );
// ASSERT_TRUE( sym->isSymbol() );
ASSERT_TRUE( sym->isGlobal() );
ASSERT_FALSE( sym->isWeak() );
ASSERT_FALSE( sym->isLocal() );
ASSERT_TRUE( sym->isDefine() );
ASSERT_FALSE( sym->isUndef() );
ASSERT_FALSE( sym->isDyn() );
ASSERT_FALSE( sym->isCommon() );
ASSERT_FALSE( sym->isIndirect() );
ASSERT_TRUE( ResolveInfo::NoType == sym->type());
ASSERT_TRUE( ResolveInfo::Define == sym->desc() );
ASSERT_TRUE( 0 == sym->binding() );
ASSERT_TRUE( 0 == sym->other() );
sym->setDesc(ResolveInfo::Common);
ASSERT_FALSE( sym->isSymbol() );
// ASSERT_TRUE( sym->isSymbol() );
ASSERT_TRUE( sym->isGlobal() );
ASSERT_FALSE( sym->isWeak() );
ASSERT_FALSE( sym->isLocal() );
ASSERT_FALSE( sym->isDyn() );
ASSERT_FALSE( sym->isDefine() );
ASSERT_FALSE( sym->isUndef() );
ASSERT_TRUE( sym->isCommon() );
ASSERT_FALSE( sym->isIndirect() );
ASSERT_TRUE( ResolveInfo::NoType == sym->type());
ASSERT_TRUE( ResolveInfo::Common == sym->desc() );
ASSERT_TRUE( 0 == sym->binding() );
ASSERT_TRUE( 0 == sym->other() );
sym->setDesc(ResolveInfo::Indirect);
ASSERT_FALSE( sym->isSymbol() );
ASSERT_TRUE( sym->isGlobal() );
ASSERT_FALSE( sym->isWeak() );
ASSERT_FALSE( sym->isLocal() );
ASSERT_FALSE( sym->isDyn() );
ASSERT_FALSE( sym->isDefine() );
ASSERT_FALSE( sym->isUndef() );
ASSERT_FALSE( sym->isCommon() );
ASSERT_TRUE( sym->isIndirect() );
ASSERT_TRUE( ResolveInfo::NoType == sym->type());
ASSERT_TRUE( ResolveInfo::Indirect == sym->desc() );
ASSERT_TRUE( 0 == sym->binding() );
ASSERT_TRUE( 0 == sym->other() );
sym->setDesc(ResolveInfo::Undefined);
ASSERT_FALSE( sym->isSymbol() );
ASSERT_TRUE( sym->isGlobal() );
ASSERT_FALSE( sym->isWeak() );
ASSERT_FALSE( sym->isLocal() );
ASSERT_FALSE( sym->isDyn() );
ASSERT_TRUE( sym->isUndef() );
ASSERT_FALSE( sym->isDefine() );
ASSERT_FALSE( sym->isCommon() );
ASSERT_FALSE( sym->isIndirect() );
ASSERT_TRUE( ResolveInfo::NoType == sym->type());
ASSERT_TRUE( 0 == sym->desc() );
ASSERT_TRUE( 0 == sym->binding() );
ASSERT_TRUE( 0 == sym->other() );
}
void ARMGNULDBackend::scanGlobalReloc(Relocation& pReloc,
const LDSymbol& pInputSym,
MCLinker& pLinker,
const MCLDInfo& pLDInfo,
const Output& pOutput)
{
// rsym - The relocation target symbol
ResolveInfo* rsym = pReloc.symInfo();
switch(pReloc.type()) {
// Set R_ARM_TARGET1 to R_ARM_ABS32
// Ref: GNU gold 1.11 arm.cc, line 9892
case llvm::ELF::R_ARM_TARGET1:
pReloc.setType(llvm::ELF::R_ARM_ABS32);
case llvm::ELF::R_ARM_ABS32:
case llvm::ELF::R_ARM_ABS16:
case llvm::ELF::R_ARM_ABS12:
case llvm::ELF::R_ARM_THM_ABS5:
case llvm::ELF::R_ARM_ABS8:
case llvm::ELF::R_ARM_BASE_ABS:
case llvm::ELF::R_ARM_MOVW_ABS_NC:
case llvm::ELF::R_ARM_MOVT_ABS:
case llvm::ELF::R_ARM_THM_MOVW_ABS_NC:
case llvm::ELF::R_ARM_THM_MOVT_ABS:
case llvm::ELF::R_ARM_ABS32_NOI: {
// Absolute relocation type, symbol may needs PLT entry or
// dynamic relocation entry
if(isSymbolNeedsPLT(*rsym, pLDInfo, pOutput)) {
// create plt for this symbol if it does not have one
if(!(rsym->reserved() & 0x8u)){
// Create .got section if it doesn't exist
if(NULL == m_pGOT)
createARMGOT(pLinker, pOutput);
// create .plt and .rel.plt if not exist
if(NULL == m_pPLT)
createARMPLTandRelPLT(pLinker, pOutput);
// Symbol needs PLT entry, we need to reserve a PLT entry
// and the corresponding GOT and dynamic relocation entry
// in .got and .rel.plt. (GOT entry will be reserved simultaneously
// when calling ARMPLT->reserveEntry())
m_pPLT->reserveEntry();
m_pRelPLT->reserveEntry(*m_pRelocFactory);
// set PLT bit
rsym->setReserved(rsym->reserved() | 0x8u);
}
}
if(isSymbolNeedsDynRel(*rsym, pOutput, true)) {
checkValidReloc(pReloc, pLDInfo, pOutput);
// symbol needs dynamic relocation entry, reserve an entry in .rel.dyn
// create .rel.dyn section if not exist
if(NULL == m_pRelDyn)
createARMRelDyn(pLinker, pOutput);
m_pRelDyn->reserveEntry(*m_pRelocFactory);
// set Rel bit
rsym->setReserved(rsym->reserved() | 0x1u);
}
return;
}
case llvm::ELF::R_ARM_GOTOFF32:
case llvm::ELF::R_ARM_GOTOFF12: {
// A GOT section is needed
if(NULL == m_pGOT)
createARMGOT(pLinker, pOutput);
return;
}
case llvm::ELF::R_ARM_BASE_PREL:
// FIXME: Currently we only support R_ARM_BASE_PREL against
// symbol _GLOBAL_OFFSET_TABLE_
if(rsym != m_pGOTSymbol->resolveInfo()) {
llvm::report_fatal_error(llvm::Twine("Do not support relocation '") +
llvm::Twine("R_ARM_BASE_PREL' against symbol '") +
llvm::Twine(rsym->name()) +
llvm::Twine(".'"));
}
case llvm::ELF::R_ARM_REL32:
case llvm::ELF::R_ARM_LDR_PC_G0:
case llvm::ELF::R_ARM_SBREL32:
case llvm::ELF::R_ARM_THM_PC8:
case llvm::ELF::R_ARM_MOVW_PREL_NC:
case llvm::ELF::R_ARM_MOVT_PREL:
case llvm::ELF::R_ARM_THM_MOVW_PREL_NC:
case llvm::ELF::R_ARM_THM_MOVT_PREL:
case llvm::ELF::R_ARM_THM_ALU_PREL_11_0:
case llvm::ELF::R_ARM_THM_PC12:
case llvm::ELF::R_ARM_REL32_NOI:
case llvm::ELF::R_ARM_ALU_PC_G0_NC:
case llvm::ELF::R_ARM_ALU_PC_G0:
case llvm::ELF::R_ARM_ALU_PC_G1_NC:
case llvm::ELF::R_ARM_ALU_PC_G1:
case llvm::ELF::R_ARM_ALU_PC_G2:
case llvm::ELF::R_ARM_LDR_PC_G1:
case llvm::ELF::R_ARM_LDR_PC_G2:
case llvm::ELF::R_ARM_LDRS_PC_G0:
case llvm::ELF::R_ARM_LDRS_PC_G1:
case llvm::ELF::R_ARM_LDRS_PC_G2:
case llvm::ELF::R_ARM_LDC_PC_G0:
case llvm::ELF::R_ARM_LDC_PC_G1:
case llvm::ELF::R_ARM_LDC_PC_G2:
case llvm::ELF::R_ARM_ALU_SB_G0_NC:
case llvm::ELF::R_ARM_ALU_SB_G0:
case llvm::ELF::R_ARM_ALU_SB_G1_NC:
case llvm::ELF::R_ARM_ALU_SB_G1:
case llvm::ELF::R_ARM_ALU_SB_G2:
case llvm::ELF::R_ARM_LDR_SB_G0:
case llvm::ELF::R_ARM_LDR_SB_G1:
case llvm::ELF::R_ARM_LDR_SB_G2:
case llvm::ELF::R_ARM_LDRS_SB_G0:
case llvm::ELF::R_ARM_LDRS_SB_G1:
case llvm::ELF::R_ARM_LDRS_SB_G2:
case llvm::ELF::R_ARM_LDC_SB_G0:
case llvm::ELF::R_ARM_LDC_SB_G1:
case llvm::ELF::R_ARM_LDC_SB_G2:
case llvm::ELF::R_ARM_MOVW_BREL_NC:
case llvm::ELF::R_ARM_MOVT_BREL:
case llvm::ELF::R_ARM_MOVW_BREL:
case llvm::ELF::R_ARM_THM_MOVW_BREL_NC:
case llvm::ELF::R_ARM_THM_MOVT_BREL:
case llvm::ELF::R_ARM_THM_MOVW_BREL: {
// Relative addressing relocation, may needs dynamic relocation
if(isSymbolNeedsDynRel(*rsym, pOutput, false)) {
checkValidReloc(pReloc, pLDInfo, pOutput);
// create .rel.dyn section if not exist
if(NULL == m_pRelDyn)
createARMRelDyn(pLinker, pOutput);
m_pRelDyn->reserveEntry(*m_pRelocFactory);
// set Rel bit
rsym->setReserved(rsym->reserved() | 0x1u);
}
return;
}
case llvm::ELF::R_ARM_THM_CALL:
case llvm::ELF::R_ARM_PLT32:
case llvm::ELF::R_ARM_CALL:
case llvm::ELF::R_ARM_JUMP24:
case llvm::ELF::R_ARM_THM_JUMP24:
case llvm::ELF::R_ARM_SBREL31:
case llvm::ELF::R_ARM_PREL31:
case llvm::ELF::R_ARM_THM_JUMP19:
case llvm::ELF::R_ARM_THM_JUMP6:
case llvm::ELF::R_ARM_THM_JUMP11:
case llvm::ELF::R_ARM_THM_JUMP8: {
// These are branch relocation (except PREL31)
// A PLT entry is needed when building shared library
// return if we already create plt for this symbol
if(rsym->reserved() & 0x8u)
return;
// if symbol is defined in the ouput file and it's not
// preemptible, no need plt
if(rsym->isDefine() && !rsym->isDyn() &&
!isSymbolPreemptible(*rsym, pLDInfo, pOutput)) {
return;
}
// Create .got section if it doesn't exist
if(NULL == m_pGOT)
createARMGOT(pLinker, pOutput);
// create .plt and .rel.plt if not exist
if(NULL == m_pPLT)
createARMPLTandRelPLT(pLinker, pOutput);
// Symbol needs PLT entry, we need to reserve a PLT entry
// and the corresponding GOT and dynamic relocation entry
// in .got and .rel.plt. (GOT entry will be reserved simultaneously
// when calling ARMPLT->reserveEntry())
m_pPLT->reserveEntry();
m_pRelPLT->reserveEntry(*m_pRelocFactory);
// set PLT bit
rsym->setReserved(rsym->reserved() | 0x8u);
return;
}
// Set R_ARM_TARGET2 to R_ARM_GOT_PREL
// Ref: GNU gold 1.11 arm.cc, line 9892
case llvm::ELF::R_ARM_TARGET2:
pReloc.setType(llvm::ELF::R_ARM_GOT_PREL);
case llvm::ELF::R_ARM_GOT_BREL:
case llvm::ELF::R_ARM_GOT_ABS:
case llvm::ELF::R_ARM_GOT_PREL: {
// Symbol needs GOT entry, reserve entry in .got
// return if we already create GOT for this symbol
if(rsym->reserved() & 0x6u)
return;
if(NULL == m_pGOT)
createARMGOT(pLinker, pOutput);
m_pGOT->reserveEntry();
// If building shared object or the symbol is undefined, a dynamic
// relocation is needed to relocate this GOT entry. Reserve an
// entry in .rel.dyn
if(Output::DynObj == pOutput.type() || rsym->isUndef() || rsym->isDyn()) {
// create .rel.dyn section if not exist
if(NULL == m_pRelDyn)
createARMRelDyn(pLinker, pOutput);
m_pRelDyn->reserveEntry(*m_pRelocFactory);
// set GOTRel bit
rsym->setReserved(rsym->reserved() | 0x4u);
return;
}
// set GOT bit
rsym->setReserved(rsym->reserved() | 0x2u);
return;
}
case llvm::ELF::R_ARM_COPY:
case llvm::ELF::R_ARM_GLOB_DAT:
case llvm::ELF::R_ARM_JUMP_SLOT:
case llvm::ELF::R_ARM_RELATIVE: {
// These are relocation type for dynamic linker, shold not
// appear in object file.
llvm::report_fatal_error(llvm::Twine("Unexpected reloc ") +
llvm::Twine((int)pReloc.type()) +
llvm::Twine(" in object file"));
break;
}
default: {
break;
}
} // end switch
}
void ARMGNULDBackend::setUpReachedSectionsForGC(const Module& pModule,
GarbageCollection::SectionReachedListMap& pSectReachedListMap) const
{
// traverse all the input relocations to find the relocation sections applying
// .ARM.exidx sections
Module::const_obj_iterator input, inEnd = pModule.obj_end();
for (input = pModule.obj_begin(); input != inEnd; ++input) {
LDContext::const_sect_iterator rs,
rsEnd = (*input)->context()->relocSectEnd();
for (rs = (*input)->context()->relocSectBegin(); rs != rsEnd; ++rs) {
// bypass the discarded relocation section
// 1. its section kind is changed to Ignore. (The target section is a
// discarded group section.)
// 2. it has no reloc data. (All symbols in the input relocs are in the
// discarded group sections)
LDSection* reloc_sect = *rs;
LDSection* apply_sect = reloc_sect->getLink();
if ((LDFileFormat::Ignore == reloc_sect->kind()) ||
(!reloc_sect->hasRelocData()))
continue;
if (llvm::ELF::SHT_ARM_EXIDX == apply_sect->type()) {
// 1. set up the reference according to relocations
bool add_first = false;
GarbageCollection::SectionListTy* reached_sects = NULL;
RelocData::iterator reloc_it, rEnd = reloc_sect->getRelocData()->end();
for (reloc_it = reloc_sect->getRelocData()->begin(); reloc_it != rEnd;
++reloc_it) {
Relocation* reloc = llvm::cast<Relocation>(reloc_it);
ResolveInfo* sym = reloc->symInfo();
// only the target symbols defined in the input fragments can make the
// reference
if (NULL == sym)
continue;
if (!sym->isDefine() || !sym->outSymbol()->hasFragRef())
continue;
// only the target symbols defined in the concerned sections can make
// the reference
const LDSection* target_sect =
&sym->outSymbol()->fragRef()->frag()->getParent()->getSection();
if (target_sect->kind() != LDFileFormat::TEXT &&
target_sect->kind() != LDFileFormat::DATA &&
target_sect->kind() != LDFileFormat::BSS)
continue;
// setup the reached list, if we first add the element to reached list
// of this section, create an entry in ReachedSections map
if (!add_first) {
reached_sects = &pSectReachedListMap.getReachedList(*apply_sect);
add_first = true;
}
reached_sects->insert(target_sect);
}
reached_sects = NULL;
add_first = false;
// 2. set up the reference from XXX to .ARM.exidx.XXX
assert(apply_sect->getLink() != NULL);
pSectReachedListMap.addReference(*apply_sect->getLink(), *apply_sect);
}
}
}
}