[lld] r249955 - ELF2: Remove ProgramHeader class and use Elf_Phdr directly. NFC.
Rafael Espíndola via llvm-commits
llvm-commits at lists.llvm.org
Sun Oct 11 06:58:18 PDT 2015
The change to use a std::unordered_set is hilly questionable. You
could have kept just a pair of Elf_Phdr and bool, no?
On 11 October 2015 at 09:48, Rafael Espíndola
<rafael.espindola at gmail.com> wrote:
> Functions names normally start with a verb. So it should probably be
> copyPhdr and setPhdr.
>
> On 10 October 2015 at 18:34, Rui Ueyama via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
>> Author: ruiu
>> Date: Sat Oct 10 17:34:30 2015
>> New Revision: 249955
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=249955&view=rev
>> Log:
>> ELF2: Remove ProgramHeader class and use Elf_Phdr directly. NFC.
>>
>> Modified:
>> lld/trunk/ELF/Writer.cpp
>>
>> Modified: lld/trunk/ELF/Writer.cpp
>> URL: http://llvm.org/viewvc/llvm-project/lld/trunk/ELF/Writer.cpp?rev=249955&r1=249954&r2=249955&view=diff
>> ==============================================================================
>> --- lld/trunk/ELF/Writer.cpp (original)
>> +++ lld/trunk/ELF/Writer.cpp Sat Oct 10 17:34:30 2015
>> @@ -14,6 +14,7 @@
>> #include "Target.h"
>>
>> #include "llvm/Support/FileOutputBuffer.h"
>> +#include <unordered_set>
>>
>> using namespace llvm;
>> using namespace llvm::ELF;
>> @@ -24,7 +25,7 @@ using namespace lld::elf2;
>>
>> namespace {
>>
>> -static uint32_t toPHDRFlags(uint64_t Flags) {
>> +static uint32_t toPhdrFlags(uint64_t Flags) {
>> uint32_t Ret = PF_R;
>> if (Flags & SHF_WRITE)
>> Ret |= PF_W;
>> @@ -33,34 +34,6 @@ static uint32_t toPHDRFlags(uint64_t Fla
>> return Ret;
>> }
>>
>> -template <class ELFT> struct ProgramHeader {
>> - typedef typename ELFFile<ELFT>::uintX_t uintX_t;
>> - typedef typename ELFFile<ELFT>::Elf_Phdr Elf_Phdr;
>> -
>> - ProgramHeader(uintX_t Type, uintX_t Flags, uintX_t FileOff, uintX_t VA) {
>> - std::memset(&Header, 0, sizeof(Elf_Phdr));
>> - Header.p_type = Type;
>> - Header.p_flags = Flags;
>> - Header.p_align = Target->getPageSize();
>> - Header.p_offset = FileOff;
>> - Header.p_vaddr = VA;
>> - Header.p_paddr = VA;
>> - }
>> -
>> - void setValuesFromSection(OutputSectionBase<ELFT::Is64Bits> *Sec) {
>> - Header.p_flags = toPHDRFlags(Sec->getFlags());
>> - Header.p_offset = Sec->getFileOff();
>> - Header.p_vaddr = Sec->getVA();
>> - Header.p_paddr = Header.p_vaddr;
>> - Header.p_filesz = Sec->getSize();
>> - Header.p_memsz = Header.p_filesz;
>> - Header.p_align = Sec->getAlign();
>> - }
>> -
>> - Elf_Phdr Header;
>> - bool Closed = false;
>> -};
>> -
>> // The writer writes a SymbolTable result to a file.
>> template <class ELFT> class Writer {
>> public:
>> @@ -100,13 +73,17 @@ private:
>> std::vector<OutputSectionBase<ELFT::Is64Bits> *> OutputSections;
>> unsigned getNumSections() const { return OutputSections.size() + 1; }
>>
>> + void phdrSet(Elf_Phdr *PH, uint32_t Type, uint32_t Flags, uintX_t FileOff,
>> + uintX_t VA, uintX_t Align);
>> + void phdrCopy(Elf_Phdr *PH, OutputSectionBase<ELFT::Is64Bits> *From);
>> +
>> llvm::BumpPtrAllocator PAlloc;
>> SymbolTable<ELFT> &Symtab;
>> - std::vector<ProgramHeader<ELFT> *> PHDRs;
>> - ProgramHeader<ELFT> PhdrPHDR{PT_PHDR, PF_R, 0, 0};
>> - ProgramHeader<ELFT> FileHeaderPHDR{PT_LOAD, PF_R, 0, 0};
>> - ProgramHeader<ELFT> InterpPHDR{PT_INTERP, 0, 0, 0};
>> - ProgramHeader<ELFT> DynamicPHDR{PT_DYNAMIC, 0, 0, 0};
>> + std::vector<Elf_Phdr *> Phdrs;
>> + Elf_Phdr PhdrPhdr;
>> + Elf_Phdr FileHeaderPhdr;
>> + Elf_Phdr InterpPhdr;
>> + Elf_Phdr DynamicPhdr;
>>
>> uintX_t FileSize;
>> uintX_t ProgramHeaderOff;
>> @@ -473,7 +450,7 @@ template <class ELFT> void Writer<ELFT>:
>> }
>>
>> template <class ELFT>
>> -static bool needsPHDR(OutputSectionBase<ELFT::Is64Bits> *Sec) {
>> +static bool needsPhdr(OutputSectionBase<ELFT::Is64Bits> *Sec) {
>> return Sec->getFlags() & SHF_ALLOC;
>> }
>>
>> @@ -481,50 +458,44 @@ static bool needsPHDR(OutputSectionBase<
>> // file offsets.
>> template <class ELFT> void Writer<ELFT>::assignAddresses() {
>> assert(!OutputSections.empty() && "No output sections to layout!");
>> - uintX_t VA = getVAStart();
>> - uintX_t FileOff = 0;
>> -
>> - FileOff += sizeof(Elf_Ehdr);
>> - VA += sizeof(Elf_Ehdr);
>> + uintX_t VA = getVAStart() + sizeof(Elf_Ehdr);
>> + uintX_t FileOff = sizeof(Elf_Ehdr);
>>
>> - // The first PHDR entry is PT_PHDR which describes the program header itself.
>> - PHDRs.push_back(&PhdrPHDR);
>> - PhdrPHDR.Header.p_align = 8;
>> - PhdrPHDR.Header.p_offset = FileOff;
>> - PhdrPHDR.Header.p_vaddr = VA;
>> - PhdrPHDR.Header.p_paddr = VA;
>> + // The first Phdr entry is PT_PHDR which describes the program header itself.
>> + Phdrs.push_back(&PhdrPhdr);
>> + phdrSet(&PhdrPhdr, PT_PHDR, PF_R, FileOff, VA, /*Align=*/8);
>>
>> - // Reserve space for PHDRs.
>> + // Reserve space for Phdrs.
>> ProgramHeaderOff = FileOff;
>> FileOff = RoundUpToAlignment(FileOff, Target->getPageSize());
>> VA = RoundUpToAlignment(VA, Target->getPageSize());
>>
>> if (needsInterpSection())
>> - PHDRs.push_back(&InterpPHDR);
>> + Phdrs.push_back(&InterpPhdr);
>>
>> - // Create a PHDR for the file header.
>> - PHDRs.push_back(&FileHeaderPHDR);
>> - FileHeaderPHDR.Header.p_vaddr = getVAStart();
>> - FileHeaderPHDR.Header.p_paddr = getVAStart();
>> - FileHeaderPHDR.Header.p_align = Target->getPageSize();
>> + // Create a Phdr for the file header.
>> + Phdrs.push_back(&FileHeaderPhdr);
>> + phdrSet(&FileHeaderPhdr, PT_LOAD, PF_R, 0, getVAStart(),
>> + Target->getPageSize());
>>
>> + std::unordered_set<Elf_Phdr *> Closed;
>> for (OutputSectionBase<ELFT::Is64Bits> *Sec : OutputSections) {
>> if (Sec->getSize()) {
>> - uintX_t Flags = toPHDRFlags(Sec->getFlags());
>> - ProgramHeader<ELFT> *Last = PHDRs.back();
>> - if (Last->Header.p_flags != Flags || !needsPHDR<ELFT>(Sec)) {
>> - // Flags changed. End current PHDR and potentially create a new one.
>> - if (!Last->Closed) {
>> - Last->Header.p_filesz = FileOff - Last->Header.p_offset;
>> - Last->Header.p_memsz = VA - Last->Header.p_vaddr;
>> - Last->Closed = true;
>> + uintX_t Flags = toPhdrFlags(Sec->getFlags());
>> + Elf_Phdr *Last = Phdrs.back();
>> + if (Last->p_flags != Flags || !needsPhdr<ELFT>(Sec)) {
>> + // Flags changed. End current Phdr and potentially create a new one.
>> + if (Closed.insert(Last).second) {
>> + Last->p_filesz = FileOff - Last->p_offset;
>> + Last->p_memsz = VA - Last->p_vaddr;
>> }
>>
>> - if (needsPHDR<ELFT>(Sec)) {
>> + if (needsPhdr<ELFT>(Sec)) {
>> VA = RoundUpToAlignment(VA, Target->getPageSize());
>> FileOff = RoundUpToAlignment(FileOff, Target->getPageSize());
>> - PHDRs.push_back(new (PAlloc)
>> - ProgramHeader<ELFT>(PT_LOAD, Flags, FileOff, VA));
>> + auto *PH = new (PAlloc) Elf_Phdr;
>> + phdrSet(PH, PT_LOAD, Flags, FileOff, VA, Target->getPageSize());
>> + Phdrs.push_back(PH);
>> }
>> }
>> }
>> @@ -542,17 +513,22 @@ template <class ELFT> void Writer<ELFT>:
>> FileOff += Size;
>> }
>>
>> - // Add a PHDR for the dynamic table.
>> - if (needsDynamicSections())
>> - PHDRs.push_back(&DynamicPHDR);
>> -
>> - FileOff += OffsetToAlignment(FileOff, ELFT::Is64Bits ? 8 : 4);
>> + if (needsInterpSection()) {
>> + InterpPhdr.p_type = PT_INTERP;
>> + phdrCopy(&InterpPhdr, Out<ELFT>::Interp);
>> + }
>> + if (needsDynamicSections()) {
>> + Phdrs.push_back(&DynamicPhdr);
>> + DynamicPhdr.p_type = PT_DYNAMIC;
>> + phdrCopy(&DynamicPhdr, Out<ELFT>::Dynamic);
>> + }
>>
>> // Fix up the first entry's size.
>> - PhdrPHDR.Header.p_filesz = sizeof(Elf_Phdr) * PHDRs.size();
>> - PhdrPHDR.Header.p_memsz = sizeof(Elf_Phdr) * PHDRs.size();
>> + PhdrPhdr.p_filesz = sizeof(Elf_Phdr) * Phdrs.size();
>> + PhdrPhdr.p_memsz = sizeof(Elf_Phdr) * Phdrs.size();
>>
>> // Add space for section headers.
>> + FileOff = RoundUpToAlignment(FileOff, ELFT::Is64Bits ? 8 : 4);
>> SectionHeaderOff = FileOff;
>> FileOff += getNumSections() * sizeof(Elf_Shdr);
>> FileSize = FileOff;
>> @@ -587,26 +563,21 @@ template <class ELFT> void Writer<ELFT>:
>> EHdr->e_shoff = SectionHeaderOff;
>> EHdr->e_ehsize = sizeof(Elf_Ehdr);
>> EHdr->e_phentsize = sizeof(Elf_Phdr);
>> - EHdr->e_phnum = PHDRs.size();
>> + EHdr->e_phnum = Phdrs.size();
>> EHdr->e_shentsize = sizeof(Elf_Shdr);
>> EHdr->e_shnum = getNumSections();
>> EHdr->e_shstrndx = Out<ELFT>::StrTab->getSectionIndex();
>>
>> // If nothing was merged into the file header PT_LOAD, set the size correctly.
>> - if (FileHeaderPHDR.Header.p_filesz == Target->getPageSize()) {
>> - uint64_t Size = sizeof(Elf_Ehdr) + sizeof(Elf_Phdr) * PHDRs.size();
>> - FileHeaderPHDR.Header.p_filesz = Size;
>> - FileHeaderPHDR.Header.p_memsz = Size;
>> + if (FileHeaderPhdr.p_filesz == Target->getPageSize()) {
>> + uint64_t Size = sizeof(Elf_Ehdr) + sizeof(Elf_Phdr) * Phdrs.size();
>> + FileHeaderPhdr.p_filesz = Size;
>> + FileHeaderPhdr.p_memsz = Size;
>> }
>>
>> - if (needsInterpSection())
>> - InterpPHDR.setValuesFromSection(Out<ELFT>::Interp);
>> - if (needsDynamicSections())
>> - DynamicPHDR.setValuesFromSection(Out<ELFT>::Dynamic);
>> -
>> auto PHdrs = reinterpret_cast<Elf_Phdr *>(Buf + EHdr->e_phoff);
>> - for (ProgramHeader<ELFT> *PHDR : PHDRs)
>> - *PHdrs++ = PHDR->Header;
>> + for (Elf_Phdr *PH : Phdrs)
>> + *PHdrs++ = *PH;
>>
>> auto SHdrs = reinterpret_cast<Elf_Shdr *>(Buf + EHdr->e_shoff);
>> // First entry is null.
>> @@ -631,6 +602,29 @@ template <class ELFT> void Writer<ELFT>:
>> Sec->writeTo(Buf + Sec->getFileOff());
>> }
>>
>> +template <class ELFT>
>> +void Writer<ELFT>::phdrSet(Elf_Phdr *PH, uint32_t Type, uint32_t Flags,
>> + uintX_t FileOff, uintX_t VA, uintX_t Align) {
>> + PH->p_type = Type;
>> + PH->p_flags = Flags;
>> + PH->p_offset = FileOff;
>> + PH->p_vaddr = VA;
>> + PH->p_paddr = VA;
>> + PH->p_align = Align;
>> +}
>> +
>> +template <class ELFT>
>> +void Writer<ELFT>::phdrCopy(Elf_Phdr *PH,
>> + OutputSectionBase<ELFT::Is64Bits> *From) {
>> + PH->p_flags = toPhdrFlags(From->getFlags());
>> + PH->p_offset = From->getFileOff();
>> + PH->p_vaddr = From->getVA();
>> + PH->p_paddr = From->getVA();
>> + PH->p_filesz = From->getSize();
>> + PH->p_memsz = From->getSize();
>> + PH->p_align = From->getAlign();
>> +}
>> +
>> template void lld::elf2::writeResult<ELF32LE>(SymbolTable<ELF32LE> *Symtab);
>> template void lld::elf2::writeResult<ELF32BE>(SymbolTable<ELF32BE> *Symtab);
>> template void lld::elf2::writeResult<ELF64LE>(SymbolTable<ELF64LE> *Symtab);
>>
>>
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