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//===- X86PLT.cpp ---------------------------------------------------------===//
//
// The MCLinker Project
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "X86GOTPLT.h"
#include "X86PLT.h"
#include "mcld/LD/LDSection.h"
#include "mcld/LinkerConfig.h"
#include "mcld/Support/MsgHandling.h"
#include <llvm/Support/ELF.h>
#include <llvm/Support/Casting.h>
namespace mcld {
//===----------------------------------------------------------------------===//
// PLT entry data
//===----------------------------------------------------------------------===//
X86_32DynPLT0::X86_32DynPLT0(SectionData& pParent)
: PLT::Entry<sizeof(x86_32_dyn_plt0)>(pParent) {
}
X86_32DynPLT1::X86_32DynPLT1(SectionData& pParent)
: PLT::Entry<sizeof(x86_32_dyn_plt1)>(pParent) {
}
X86_32ExecPLT0::X86_32ExecPLT0(SectionData& pParent)
: PLT::Entry<sizeof(x86_32_exec_plt0)>(pParent) {
}
X86_32ExecPLT1::X86_32ExecPLT1(SectionData& pParent)
: PLT::Entry<sizeof(x86_32_exec_plt1)>(pParent) {
}
X86_64PLT0::X86_64PLT0(SectionData& pParent)
: PLT::Entry<sizeof(x86_64_plt0)>(pParent) {
}
X86_64PLT1::X86_64PLT1(SectionData& pParent)
: PLT::Entry<sizeof(x86_64_plt1)>(pParent) {
}
//===----------------------------------------------------------------------===//
// X86PLT
//===----------------------------------------------------------------------===//
X86PLT::X86PLT(LDSection& pSection, const LinkerConfig& pConfig, int got_size)
: PLT(pSection), m_Config(pConfig) {
assert(LinkerConfig::DynObj == m_Config.codeGenType() ||
LinkerConfig::Exec == m_Config.codeGenType() ||
LinkerConfig::Binary == m_Config.codeGenType());
if (got_size == 32) {
if (LinkerConfig::DynObj == m_Config.codeGenType()) {
m_PLT0 = x86_32_dyn_plt0;
m_PLT1 = x86_32_dyn_plt1;
m_PLT0Size = sizeof(x86_32_dyn_plt0);
m_PLT1Size = sizeof(x86_32_dyn_plt1);
// create PLT0
new X86_32DynPLT0(*m_pSectionData);
} else {
m_PLT0 = x86_32_exec_plt0;
m_PLT1 = x86_32_exec_plt1;
m_PLT0Size = sizeof(x86_32_exec_plt0);
m_PLT1Size = sizeof(x86_32_exec_plt1);
// create PLT0
new X86_32ExecPLT0(*m_pSectionData);
}
} else {
assert(got_size == 64);
m_PLT0 = x86_64_plt0;
m_PLT1 = x86_64_plt1;
m_PLT0Size = sizeof(x86_64_plt0);
m_PLT1Size = sizeof(x86_64_plt1);
// create PLT0
new X86_64PLT0(*m_pSectionData);
}
}
X86PLT::~X86PLT() {
}
void X86PLT::finalizeSectionSize() {
uint64_t size = 0;
// plt0 size
size = getPLT0()->size();
// get first plt1 entry
X86PLT::iterator it = begin();
++it;
if (end() != it) {
// plt1 size
PLTEntryBase* plt1 = &(llvm::cast<PLTEntryBase>(*it));
size += (m_pSectionData->size() - 1) * plt1->size();
}
m_Section.setSize(size);
uint32_t offset = 0;
SectionData::iterator frag, fragEnd = m_pSectionData->end();
for (frag = m_pSectionData->begin(); frag != fragEnd; ++frag) {
frag->setOffset(offset);
offset += frag->size();
}
}
bool X86PLT::hasPLT1() const {
return (m_pSectionData->size() > 1);
}
PLTEntryBase* X86PLT::create() {
if (LinkerConfig::DynObj == m_Config.codeGenType())
return new X86_32DynPLT1(*m_pSectionData);
else
return new X86_32ExecPLT1(*m_pSectionData);
}
PLTEntryBase* X86PLT::getPLT0() const {
iterator first = m_pSectionData->getFragmentList().begin();
assert(first != m_pSectionData->getFragmentList().end() &&
"FragmentList is empty, getPLT0 failed!");
PLTEntryBase* plt0 = &(llvm::cast<PLTEntryBase>(*first));
return plt0;
}
//===----------------------------------------------------------------------===//
// X86_32PLT
//===----------------------------------------------------------------------===//
X86_32PLT::X86_32PLT(LDSection& pSection,
X86_32GOTPLT& pGOTPLT,
const LinkerConfig& pConfig)
: X86PLT(pSection, pConfig, 32), m_GOTPLT(pGOTPLT) {
}
// FIXME: It only works on little endian machine.
void X86_32PLT::applyPLT0() {
PLTEntryBase* plt0 = getPLT0();
unsigned char* data = 0;
data = static_cast<unsigned char*>(malloc(plt0->size()));
if (!data)
fatal(diag::fail_allocate_memory_plt);
memcpy(data, m_PLT0, plt0->size());
if (m_PLT0 == x86_32_exec_plt0) {
uint32_t* offset = reinterpret_cast<uint32_t*>(data + 2);
*offset = m_GOTPLT.addr() + 4;
offset = reinterpret_cast<uint32_t*>(data + 8);
*offset = m_GOTPLT.addr() + 8;
}
plt0->setValue(data);
}
// FIXME: It only works on little endian machine.
void X86_32PLT::applyPLT1() {
assert(m_Section.addr() && ".plt base address is NULL!");
X86PLT::iterator it = m_pSectionData->begin();
X86PLT::iterator ie = m_pSectionData->end();
assert(it != ie && "FragmentList is empty, applyPLT1 failed!");
uint64_t GOTEntrySize = X86_32GOTEntry::EntrySize;
// Skip GOT0
uint64_t GOTEntryOffset = GOTEntrySize * X86GOTPLT0Num;
if (LinkerConfig::Exec == m_Config.codeGenType())
GOTEntryOffset += m_GOTPLT.addr();
// skip PLT0
uint64_t PLTEntryOffset = m_PLT0Size;
++it;
PLTEntryBase* plt1 = 0;
uint64_t PLTRelOffset = 0;
while (it != ie) {
plt1 = &(llvm::cast<PLTEntryBase>(*it));
unsigned char* data;
data = static_cast<unsigned char*>(malloc(plt1->size()));
if (!data)
fatal(diag::fail_allocate_memory_plt);
memcpy(data, m_PLT1, plt1->size());
uint32_t* offset;
offset = reinterpret_cast<uint32_t*>(data + 2);
*offset = GOTEntryOffset;
GOTEntryOffset += GOTEntrySize;
offset = reinterpret_cast<uint32_t*>(data + 7);
*offset = PLTRelOffset;
PLTRelOffset += sizeof(llvm::ELF::Elf32_Rel);
offset = reinterpret_cast<uint32_t*>(data + 12);
*offset = -(PLTEntryOffset + 12 + 4);
PLTEntryOffset += m_PLT1Size;
plt1->setValue(data);
++it;
}
}
//===----------------------------------------------------------------------===//
// X86_64PLT
//===----------------------------------------------------------------------===//
X86_64PLT::X86_64PLT(LDSection& pSection,
X86_64GOTPLT& pGOTPLT,
const LinkerConfig& pConfig)
: X86PLT(pSection, pConfig, 64), m_GOTPLT(pGOTPLT) {
}
// FIXME: It only works on little endian machine.
void X86_64PLT::applyPLT0() {
PLTEntryBase* plt0 = getPLT0();
unsigned char* data = 0;
data = static_cast<unsigned char*>(malloc(plt0->size()));
if (!data)
fatal(diag::fail_allocate_memory_plt);
memcpy(data, m_PLT0, plt0->size());
// pushq GOT + 8(%rip)
uint32_t* offset = reinterpret_cast<uint32_t*>(data + 2);
*offset = m_GOTPLT.addr() - addr() + 8 - 6;
// jmq *GOT + 16(%rip)
offset = reinterpret_cast<uint32_t*>(data + 8);
*offset = m_GOTPLT.addr() - addr() + 16 - 12;
plt0->setValue(data);
}
// FIXME: It only works on little endian machine.
void X86_64PLT::applyPLT1() {
assert(m_Section.addr() && ".plt base address is NULL!");
X86PLT::iterator it = m_pSectionData->begin();
X86PLT::iterator ie = m_pSectionData->end();
assert(it != ie && "FragmentList is empty, applyPLT1 failed!");
uint64_t GOTEntrySize = X86_64GOTEntry::EntrySize;
// compute sym@GOTPCREL of the PLT1 entry.
uint64_t SymGOTPCREL = m_GOTPLT.addr();
// Skip GOT0
SymGOTPCREL += GOTEntrySize * X86GOTPLT0Num;
// skip PLT0
uint64_t PLTEntryOffset = m_PLT0Size;
++it;
// PC-relative to entry in PLT section.
SymGOTPCREL -= addr() + PLTEntryOffset + 6;
PLTEntryBase* plt1 = 0;
uint64_t PLTRelIndex = 0;
while (it != ie) {
plt1 = &(llvm::cast<PLTEntryBase>(*it));
unsigned char* data;
data = static_cast<unsigned char*>(malloc(plt1->size()));
if (!data)
fatal(diag::fail_allocate_memory_plt);
memcpy(data, m_PLT1, plt1->size());
uint32_t* offset;
// jmpq *sym@GOTPCREL(%rip)
offset = reinterpret_cast<uint32_t*>(data + 2);
*offset = SymGOTPCREL;
SymGOTPCREL += GOTEntrySize - m_PLT1Size;
// pushq $index
offset = reinterpret_cast<uint32_t*>(data + 7);
*offset = PLTRelIndex;
PLTRelIndex++;
// jmpq plt0
offset = reinterpret_cast<uint32_t*>(data + 12);
*offset = -(PLTEntryOffset + 12 + 4);
PLTEntryOffset += m_PLT1Size;
plt1->setValue(data);
++it;
}
}
} // namespace mcld