// compute stub buffer size for the given section
unsigned RuntimeDyldImpl::computeSectionStubBufSize(ObjectImage &Obj,
const SectionRef &Section) {
unsigned StubSize = getMaxStubSize();
if (StubSize == 0) {
return 0;
}
// FIXME: this is an inefficient way to handle this. We should computed the
// necessary section allocation size in loadObject by walking all the sections
// once.
unsigned StubBufSize = 0;
for (section_iterator SI = Obj.begin_sections(), SE = Obj.end_sections();
SI != SE; ++SI) {
section_iterator RelSecI = SI->getRelocatedSection();
if (!(RelSecI == Section))
continue;
for (const RelocationRef &Reloc : SI->relocations()) {
(void)Reloc;
StubBufSize += StubSize;
}
}
// Get section data size and alignment
uint64_t Alignment64;
uint64_t DataSize;
Check(Section.getSize(DataSize));
Check(Section.getAlignment(Alignment64));
// Add stubbuf size alignment
unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
unsigned StubAlignment = getStubAlignment();
unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
if (StubAlignment > EndAlignment)
StubBufSize += StubAlignment - EndAlignment;
return StubBufSize;
}
unsigned RuntimeDyldImpl::emitSection(ObjectImage &Obj,
const SectionRef &Section,
bool IsCode) {
unsigned StubBufSize = 0,
StubSize = getMaxStubSize();
error_code err;
const ObjectFile *ObjFile = Obj.getObjectFile();
// FIXME: this is an inefficient way to handle this. We should computed the
// necessary section allocation size in loadObject by walking all the sections
// once.
if (StubSize > 0) {
for (section_iterator SI = ObjFile->begin_sections(),
SE = ObjFile->end_sections();
SI != SE; SI.increment(err), Check(err)) {
section_iterator RelSecI = SI->getRelocatedSection();
if (!(RelSecI == Section))
continue;
for (relocation_iterator I = SI->begin_relocations(),
E = SI->end_relocations(); I != E; I.increment(err), Check(err)) {
StubBufSize += StubSize;
}
}
}
StringRef data;
uint64_t Alignment64;
Check(Section.getContents(data));
Check(Section.getAlignment(Alignment64));
unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
bool IsRequired;
bool IsVirtual;
bool IsZeroInit;
bool IsReadOnly;
uint64_t DataSize;
StringRef Name;
Check(Section.isRequiredForExecution(IsRequired));
Check(Section.isVirtual(IsVirtual));
Check(Section.isZeroInit(IsZeroInit));
Check(Section.isReadOnlyData(IsReadOnly));
Check(Section.getSize(DataSize));
Check(Section.getName(Name));
if (StubSize > 0) {
unsigned StubAlignment = getStubAlignment();
unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
if (StubAlignment > EndAlignment)
StubBufSize += StubAlignment - EndAlignment;
}
unsigned Allocate;
unsigned SectionID = Sections.size();
uint8_t *Addr;
const char *pData = 0;
// Some sections, such as debug info, don't need to be loaded for execution.
// Leave those where they are.
if (IsRequired) {
Allocate = DataSize + StubBufSize;
Addr = IsCode
? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID)
: MemMgr->allocateDataSection(Allocate, Alignment, SectionID, IsReadOnly);
if (!Addr)
report_fatal_error("Unable to allocate section memory!");
// Virtual sections have no data in the object image, so leave pData = 0
if (!IsVirtual)
pData = data.data();
// Zero-initialize or copy the data from the image
if (IsZeroInit || IsVirtual)
memset(Addr, 0, DataSize);
else
memcpy(Addr, pData, DataSize);
DEBUG(dbgs() << "emitSection SectionID: " << SectionID
<< " Name: " << Name
<< " obj addr: " << format("%p", pData)
<< " new addr: " << format("%p", Addr)
<< " DataSize: " << DataSize
<< " StubBufSize: " << StubBufSize
<< " Allocate: " << Allocate
<< "\n");
Obj.updateSectionAddress(Section, (uint64_t)Addr);
}
else {
// Even if we didn't load the section, we need to record an entry for it
// to handle later processing (and by 'handle' I mean don't do anything
// with these sections).
Allocate = 0;
Addr = 0;
DEBUG(dbgs() << "emitSection SectionID: " << SectionID
<< " Name: " << Name
<< " obj addr: " << format("%p", data.data())
<< " new addr: 0"
<< " DataSize: " << DataSize
<< " StubBufSize: " << StubBufSize
<< " Allocate: " << Allocate
<< "\n");
}
Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
return SectionID;
}
