[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 06:18:55 PDT 2015
Hi,
There are a few style changes in this patch that make it hard to
review. For example, it would have been very nice to have the PHDR ->
Phdr change in one patch.
Cheers,
Rafael
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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