[llvm] r308821 - Reland "[LLVM][llvm-objcopy] Added basic plumbing to get things started"
David Blaikie via llvm-commits
llvm-commits at lists.llvm.org
Mon Jul 24 09:01:42 PDT 2017
Could you highlight what was changed/fixed to address the reason this was
originally reverted? (good to include/highlight that in the commit message
to make it easier to review the delta, etc)
On Fri, Jul 21, 2017 at 7:34 PM Petr Hosek via llvm-commits <
llvm-commits at lists.llvm.org> wrote:
> Author: phosek
> Date: Fri Jul 21 19:33:45 2017
> New Revision: 308821
>
> URL: http://llvm.org/viewvc/llvm-project?rev=308821&view=rev
> Log:
> Reland "[LLVM][llvm-objcopy] Added basic plumbing to get things started"
>
> As discussed on llvm-dev I've implemented the first basic steps towards
> llvm-objcopy/llvm-objtool (name pending).
>
> This change adds the ability to copy (without modification) 64-bit
> little endian ELF executables that have SHT_PROGBITS, SHT_NOBITS,
> SHT_NULL and SHT_STRTAB sections.
>
> Patch by Jake Ehrlich
>
> Differential Revision: https://reviews.llvm.org/D33964
>
> Added:
> llvm/trunk/test/tools/llvm-objcopy/basic-copy.test
> llvm/trunk/test/tools/llvm-objcopy/empty-section.test
> llvm/trunk/test/tools/llvm-objcopy/program-headers.test
> llvm/trunk/tools/llvm-objcopy/CMakeLists.txt
> llvm/trunk/tools/llvm-objcopy/LLVMBuild.txt
> - copied, changed from r308818, llvm/trunk/tools/LLVMBuild.txt
> llvm/trunk/tools/llvm-objcopy/Object.cpp
> llvm/trunk/tools/llvm-objcopy/Object.h
> llvm/trunk/tools/llvm-objcopy/llvm-objcopy.cpp
> llvm/trunk/tools/llvm-objcopy/llvm-objcopy.h
> Modified:
> llvm/trunk/test/CMakeLists.txt
> llvm/trunk/tools/LLVMBuild.txt
>
> Modified: llvm/trunk/test/CMakeLists.txt
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CMakeLists.txt?rev=308821&r1=308820&r2=308821&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/CMakeLists.txt (original)
> +++ llvm/trunk/test/CMakeLists.txt Fri Jul 21 19:33:45 2017
> @@ -61,6 +61,7 @@ set(LLVM_TEST_DEPENDS
> llvm-modextract
> llvm-mt
> llvm-nm
> + llvm-objcopy
> llvm-objdump
> llvm-opt-report
> llvm-pdbutil
>
> Added: llvm/trunk/test/tools/llvm-objcopy/basic-copy.test
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-objcopy/basic-copy.test?rev=308821&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/tools/llvm-objcopy/basic-copy.test (added)
> +++ llvm/trunk/test/tools/llvm-objcopy/basic-copy.test Fri Jul 21 19:33:45
> 2017
> @@ -0,0 +1,47 @@
> +# RUN: yaml2obj %s > %t
> +# RUN: llvm-objcopy %t %t2
> +# RUN: llvm-readobj -sections %t2 | FileCheck %s
> +
> +!ELF
> +FileHeader:
> + Class: ELFCLASS64
> + Data: ELFDATA2LSB
> + Type: ET_EXEC
> + Machine: EM_X86_64
> +Sections:
> + - Name: .bss
> + Type: SHT_NOBITS
> + Flags: [ SHF_ALLOC ]
> + AddressAlign: 0x0000000000000010
> + Size: 64
> + - Name: .text
> + Type: SHT_PROGBITS
> + Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
> + AddressAlign: 0x0000000000000010
> + Content: "00000000"
> +
> +# CHECK: Type: SHT_NULL
> +
> +# CHECK: Name: .bss
> +# CHECK-NEXT: Type: SHT_NOBITS
> +# CHECK-NEXT: Flags [
> +# CHECK-NEXT: SHF_ALLOC
> +# CHECK-NEXT: ]
> +# CHECK-NEXT: Address:
> +# CHECK-NEXT: Offset: [[OFFSET:0x[0-9A-F]+]]
> +# CHECK-NEXT: Size: 64
> +
> +# CHECK: Name: .text
> +# CHECK-NEXT: Type: SHT_PROGBITS
> +# CHECK-NEXT: Flags [
> +# CHECK-NEXT: SHF_ALLOC
> +# CHECK-NEXT: SHF_EXECINSTR
> +# CHECK-NEXT: ]
> +# CHECK-NEXT: Address:
> +# CHECK-NEXT: Offset: [[OFFSET]]
> +# CHECK-NEXT: Size: 4
> +
> +# CHECK: Name: .shstrtab
> +# CHECK-NEXT: Type: SHT_STRTAB
> +# CHECK-NEXT: Flags [
> +# CHECK-NEXT: ]
>
> Added: llvm/trunk/test/tools/llvm-objcopy/empty-section.test
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-objcopy/empty-section.test?rev=308821&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/tools/llvm-objcopy/empty-section.test (added)
> +++ llvm/trunk/test/tools/llvm-objcopy/empty-section.test Fri Jul 21
> 19:33:45 2017
> @@ -0,0 +1,55 @@
> +# RUN: yaml2obj %s > %t
> +# RUN: llvm-objcopy %t %t2
> +# RUN: llvm-readobj -sections %t2 | FileCheck %s
> +
> +!ELF
> +FileHeader:
> + Class: ELFCLASS64
> + Data: ELFDATA2LSB
> + Type: ET_EXEC
> + Machine: EM_X86_64
> +Sections:
> + - Name: .text
> + Type: SHT_PROGBITS
> + Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
> + Address: 0x0
> + AddressAlign: 0x0000000000001000
> + Content: "00000000"
> + - Name: .empty
> + Type: SHT_PROGBITS
> + Flags: [ SHF_ALLOC ]
> + Address: 0x1000
> + AddressAlign: 0x0000000000001000
> + Content: ""
> + - Name: .data
> + Type: SHT_PROGBITS
> + Flags: [ SHF_ALLOC ]
> + Address: 0x1000
> + AddressAlign: 0x0000000000001000
> + Content: "00000000"
> +
> +
> +# CHECK: Name: .text
> +# CHECK-NEXT: Type: SHT_PROGBITS
> +# CHECK-NEXT: Flags [
> +# CHECK-NEXT: SHF_ALLOC
> +# CHECK-NEXT: SHF_EXECINSTR
> +# CHECK-NEXT: ]
> +
> +# CHECK: Name: .empty
> +# CHECK-NEXT: Type: SHT_PROGBITS
> +# CHECK-NEXT: Flags [
> +# CHECK-NEXT: SHF_ALLOC
> +# CHECK-NEXT: ]
> +# CHECK-NEXT: Address: 0x1000
> +# CHECK-NEXT: Offset: 0x2000
> +# CHECK-NEXT: Size: 0
> +
> +# CHECK: Name: .data
> +# CHECK-NEXT: Type: SHT_PROGBITS
> +# CHECK-NEXT: Flags [
> +# CHECK-NEXT: SHF_ALLOC
> +# CHECK-NEXT: ]
> +# CHECK-NEXT: Address: 0x1000
> +# CHECK-NEXT: Offset: 0x2000
> +# CHECK-NEXT: Size: 4
>
> Added: llvm/trunk/test/tools/llvm-objcopy/program-headers.test
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-objcopy/program-headers.test?rev=308821&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/tools/llvm-objcopy/program-headers.test (added)
> +++ llvm/trunk/test/tools/llvm-objcopy/program-headers.test Fri Jul 21
> 19:33:45 2017
> @@ -0,0 +1,68 @@
> +# RUN: yaml2obj %s -o %t
> +# RUN: llvm-objcopy %t %t2
> +# RUN: llvm-readobj -program-headers %t2 | FileCheck %s
> +
> +!ELF
> +FileHeader:
> + Class: ELFCLASS64
> + Data: ELFDATA2LSB
> + Type: ET_EXEC
> + Machine: EM_X86_64
> +Sections:
> + - Name: .text
> + Type: SHT_PROGBITS
> + Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
> + AddressAlign: 0x0000000000001000
> + Content: "00000000"
> + - Name: .init
> + Type: SHT_PROGBITS
> + Flags: [ SHF_ALLOC, SHF_EXECINSTR ]
> + Content: "00000000"
> + AddressAlign: 0x0000000000000010
> + - Name: .data
> + Type: SHT_PROGBITS
> + Flags: [ SHF_ALLOC ]
> + Content: "00000000"
> + AddressAlign: 0x0000000000001000
> +ProgramHeaders:
> + - Type: PT_LOAD
> + Flags: [ PF_X, PF_R ]
> + VAddr: 0xAAAA1000
> + PAddr: 0xFFFF1000
> + Sections:
> + - Section: .text
> + - Section: .init
> + - Type: PT_LOAD
> + Flags: [ PF_R ]
> + VAddr: 0xAAAA2000
> + PAddr: 0xFFFF2000
> + Sections:
> + - Section: .data
> +
> +#CHECK: ProgramHeaders [
> +#CHECK-NEXT: ProgramHeader {
> +#CHECK-NEXT: Type: PT_LOAD
> +#CHECK-NEXT: Offset: 0x1000
> +#CHECK-NEXT: VirtualAddress: 0xAAAA1000
> +#CHECK-NEXT: PhysicalAddress: 0xFFFF1000
> +#CHECK-NEXT: FileSize: 20
> +#CHECK-NEXT: MemSize: 20
> +#CHECK-NEXT: Flags [
> +#CHECK-NEXT: PF_R
> +#CHECK-NEXT: PF_X
> +#CHECK-NEXT: ]
> +#CHECK-NEXT: Alignment: 4096
> +#CHECK-NEXT: }
> +#CHECK-NEXT: ProgramHeader {
> +#CHECK-NEXT: Type: PT_LOAD
> +#CHECK-NEXT: Offset: 0x2000
> +#CHECK-NEXT: VirtualAddress: 0xAAAA2000
> +#CHECK-NEXT: PhysicalAddress: 0xFFFF2000
> +#CHECK-NEXT: FileSize: 4
> +#CHECK-NEXT: MemSize: 4
> +#CHECK-NEXT: Flags [
> +#CHECK-NEXT: PF_R
> +#CHECK-NEXT: ]
> +#CHECK-NEXT: Alignment: 4096
> +#CHECK-NEXT: }
> +#CHECK-NEXT:]
>
> Modified: llvm/trunk/tools/LLVMBuild.txt
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/LLVMBuild.txt?rev=308821&r1=308820&r2=308821&view=diff
>
> ==============================================================================
> --- llvm/trunk/tools/LLVMBuild.txt (original)
> +++ llvm/trunk/tools/LLVMBuild.txt Fri Jul 21 19:33:45 2017
> @@ -40,6 +40,7 @@ subdirectories =
> llvm-modextract
> llvm-mt
> llvm-nm
> + llvm-objcopy
> llvm-objdump
> llvm-pdbutil
> llvm-profdata
>
> Added: llvm/trunk/tools/llvm-objcopy/CMakeLists.txt
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-objcopy/CMakeLists.txt?rev=308821&view=auto
>
> ==============================================================================
> --- llvm/trunk/tools/llvm-objcopy/CMakeLists.txt (added)
> +++ llvm/trunk/tools/llvm-objcopy/CMakeLists.txt Fri Jul 21 19:33:45 2017
> @@ -0,0 +1,9 @@
> +set(LLVM_LINK_COMPONENTS
> + Core
> + Object
> + Support
> + )
> +add_llvm_tool(llvm-objcopy
> + llvm-objcopy.cpp
> + Object.cpp
> + )
>
> Copied: llvm/trunk/tools/llvm-objcopy/LLVMBuild.txt (from r308818,
> llvm/trunk/tools/LLVMBuild.txt)
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-objcopy/LLVMBuild.txt?p2=llvm/trunk/tools/llvm-objcopy/LLVMBuild.txt&p1=llvm/trunk/tools/LLVMBuild.txt&r1=308818&r2=308821&rev=308821&view=diff
>
> ==============================================================================
> --- llvm/trunk/tools/LLVMBuild.txt (original)
> +++ llvm/trunk/tools/llvm-objcopy/LLVMBuild.txt Fri Jul 21 19:33:45 2017
> @@ -1,4 +1,4 @@
> -;===- ./tools/LLVMBuild.txt ------------------------------------*- Conf
> -*--===;
> +;===- ./tools/llvm-objcopy/LLVMBuild.txt -----------------------*- Conf
> -*--===;
> ;
> ; The LLVM Compiler Infrastructure
> ;
> @@ -14,42 +14,8 @@
> ; http://llvm.org/docs/LLVMBuild.html
> ;
>
> ;===------------------------------------------------------------------------===;
> -
> -[common]
> -subdirectories =
> - bugpoint
> - dsymutil
> - llc
> - lli
> - llvm-ar
> - llvm-as
> - llvm-bcanalyzer
> - llvm-cat
> - llvm-cov
> - llvm-cvtres
> - llvm-diff
> - llvm-dis
> - llvm-dwarfdump
> - llvm-dwp
> - llvm-extract
> - llvm-jitlistener
> - llvm-link
> - llvm-lto
> - llvm-mc
> - llvm-mcmarkup
> - llvm-modextract
> - llvm-mt
> - llvm-nm
> - llvm-objdump
> - llvm-pdbutil
> - llvm-profdata
> - llvm-rtdyld
> - llvm-size
> - llvm-split
> - opt
> - verify-uselistorder
> -
> [component_0]
> -type = Group
> -name = Tools
> -parent = $ROOT
> +type = Tool
> +name = llvm-objcopy
> +parent = Tools
> +required_libraries = Object
>
> Added: llvm/trunk/tools/llvm-objcopy/Object.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-objcopy/Object.cpp?rev=308821&view=auto
>
> ==============================================================================
> --- llvm/trunk/tools/llvm-objcopy/Object.cpp (added)
> +++ llvm/trunk/tools/llvm-objcopy/Object.cpp Fri Jul 21 19:33:45 2017
> @@ -0,0 +1,341 @@
> +//===- Object.cpp -----------------------------------------------*- C++
> -*-===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is distributed under the University of Illinois Open Source
> +// License. See LICENSE.TXT for details.
> +//
>
> +//===----------------------------------------------------------------------===//
> +#include "Object.h"
> +#include "llvm-objcopy.h"
> +
> +using namespace llvm;
> +using namespace object;
> +using namespace ELF;
> +
> +template <class ELFT> void Segment::writeHeader(FileOutputBuffer &Out)
> const {
> + typedef typename ELFT::Ehdr Elf_Ehdr;
> + typedef typename ELFT::Phdr Elf_Phdr;
> +
> + uint8_t *Buf = Out.getBufferStart();
> + Buf += sizeof(Elf_Ehdr) + Index * sizeof(Elf_Phdr);
> + Elf_Phdr &Phdr = *reinterpret_cast<Elf_Phdr *>(Buf);
> + Phdr.p_type = Type;
> + Phdr.p_flags = Flags;
> + Phdr.p_offset = Offset;
> + Phdr.p_vaddr = VAddr;
> + Phdr.p_paddr = PAddr;
> + Phdr.p_filesz = FileSize;
> + Phdr.p_memsz = MemSize;
> + Phdr.p_align = Align;
> +}
> +
> +void Segment::finalize() {
> + auto FirstSec = firstSection();
> + if (FirstSec) {
> + // It is possible for a gap to be at the begining of a segment.
> Because of
> + // this we need to compute the new offset based on how large this gap
> was
> + // in the source file. Section layout should have already ensured
> that this
> + // space is not used for something else.
> + uint64_t OriginalOffset = Offset;
> + Offset = FirstSec->Offset - (FirstSec->OriginalOffset -
> OriginalOffset);
> + }
> +}
> +
> +void SectionBase::finalize() {}
> +
> +template <class ELFT>
> +void SectionBase::writeHeader(FileOutputBuffer &Out) const {
> + uint8_t *Buf = Out.getBufferStart();
> + Buf += HeaderOffset;
> + typename ELFT::Shdr &Shdr = *reinterpret_cast<typename ELFT::Shdr
> *>(Buf);
> + Shdr.sh_name = NameIndex;
> + Shdr.sh_type = Type;
> + Shdr.sh_flags = Flags;
> + Shdr.sh_addr = Addr;
> + Shdr.sh_offset = Offset;
> + Shdr.sh_size = Size;
> + Shdr.sh_link = Link;
> + Shdr.sh_info = Info;
> + Shdr.sh_addralign = Align;
> + Shdr.sh_entsize = EntrySize;
> +}
> +
> +void Section::writeSection(FileOutputBuffer &Out) const {
> + if (Type == SHT_NOBITS)
> + return;
> + uint8_t *Buf = Out.getBufferStart() + Offset;
> + std::copy(std::begin(Contents), std::end(Contents), Buf);
> +}
> +
> +void StringTableSection::addString(StringRef Name) {
> + StrTabBuilder.add(Name);
> + Size = StrTabBuilder.getSize();
> +}
> +
> +uint32_t StringTableSection::findIndex(StringRef Name) const {
> + return StrTabBuilder.getOffset(Name);
> +}
> +
> +void StringTableSection::finalize() { StrTabBuilder.finalize(); }
> +
> +void StringTableSection::writeSection(FileOutputBuffer &Out) const {
> + StrTabBuilder.write(Out.getBufferStart() + Offset);
> +}
> +
> +// Returns true IFF a section is wholly inside the range of a segment
> +static bool sectionWithinSegment(const SectionBase &Section,
> + const Segment &Segment) {
> + // If a section is empty it should be treated like it has a size of 1.
> This is
> + // to clarify the case when an empty section lies on a boundary between
> two
> + // segments and ensures that the section "belongs" to the second
> segment and
> + // not the first.
> + uint64_t SecSize = Section.Size ? Section.Size : 1;
> + return Segment.Offset <= Section.OriginalOffset &&
> + Segment.Offset + Segment.FileSize >= Section.OriginalOffset +
> SecSize;
> +}
> +
> +template <class ELFT>
> +void Object<ELFT>::readProgramHeaders(const ELFFile<ELFT> &ElfFile) {
> + uint32_t Index = 0;
> + for (const auto &Phdr : unwrapOrError(ElfFile.program_headers())) {
> + Segments.emplace_back(make_unique<Segment>());
> + Segment &Seg = *Segments.back();
> + Seg.Type = Phdr.p_type;
> + Seg.Flags = Phdr.p_flags;
> + Seg.Offset = Phdr.p_offset;
> + Seg.VAddr = Phdr.p_vaddr;
> + Seg.PAddr = Phdr.p_paddr;
> + Seg.FileSize = Phdr.p_filesz;
> + Seg.MemSize = Phdr.p_memsz;
> + Seg.Align = Phdr.p_align;
> + Seg.Index = Index++;
> + for (auto &Section : Sections) {
> + if (sectionWithinSegment(*Section, Seg)) {
> + Seg.addSection(&*Section);
> + if (!Section->ParentSegment ||
> + Section->ParentSegment->Offset > Seg.Offset) {
> + Section->ParentSegment = &Seg;
> + }
> + }
> + }
> + }
> +}
> +
> +template <class ELFT>
> +std::unique_ptr<SectionBase>
> +Object<ELFT>::makeSection(const llvm::object::ELFFile<ELFT> &ElfFile,
> + const Elf_Shdr &Shdr) {
> + ArrayRef<uint8_t> Data;
> + switch (Shdr.sh_type) {
> + case SHT_STRTAB:
> + return make_unique<StringTableSection>();
> + case SHT_NOBITS:
> + return make_unique<Section>(Data);
> + default:
> + Data = unwrapOrError(ElfFile.getSectionContents(&Shdr));
> + return make_unique<Section>(Data);
> + };
> +}
> +
> +template <class ELFT>
> +void Object<ELFT>::readSectionHeaders(const ELFFile<ELFT> &ElfFile) {
> + uint32_t Index = 0;
> + for (const auto &Shdr : unwrapOrError(ElfFile.sections())) {
> + if (Index == 0) {
> + ++Index;
> + continue;
> + }
> + SecPtr Sec = makeSection(ElfFile, Shdr);
> + Sec->Name = unwrapOrError(ElfFile.getSectionName(&Shdr));
> + Sec->Type = Shdr.sh_type;
> + Sec->Flags = Shdr.sh_flags;
> + Sec->Addr = Shdr.sh_addr;
> + Sec->Offset = Shdr.sh_offset;
> + Sec->OriginalOffset = Shdr.sh_offset;
> + Sec->Size = Shdr.sh_size;
> + Sec->Link = Shdr.sh_link;
> + Sec->Info = Shdr.sh_info;
> + Sec->Align = Shdr.sh_addralign;
> + Sec->EntrySize = Shdr.sh_entsize;
> + Sec->Index = Index++;
> + Sections.push_back(std::move(Sec));
> + }
> +}
> +
> +template <class ELFT> size_t Object<ELFT>::totalSize() const {
> + // We already have the section header offset so we can calculate the
> total
> + // size by just adding up the size of each section header.
> + return SHOffset + Sections.size() * sizeof(Elf_Shdr) + sizeof(Elf_Shdr);
> +}
> +
> +template <class ELFT> Object<ELFT>::Object(const ELFObjectFile<ELFT>
> &Obj) {
> + const auto &ElfFile = *Obj.getELFFile();
> + const auto &Ehdr = *ElfFile.getHeader();
> +
> + std::copy(Ehdr.e_ident, Ehdr.e_ident + 16, Ident);
> + Type = Ehdr.e_type;
> + Machine = Ehdr.e_machine;
> + Version = Ehdr.e_version;
> + Entry = Ehdr.e_entry;
> + Flags = Ehdr.e_flags;
> +
> + readSectionHeaders(ElfFile);
> + readProgramHeaders(ElfFile);
> +
> + SectionNames =
> + dyn_cast<StringTableSection>(Sections[Ehdr.e_shstrndx - 1].get());
> +}
> +
> +template <class ELFT> void Object<ELFT>::sortSections() {
> + // Put all sections in offset order. Maintain the ordering as closely as
> + // possible while meeting that demand however.
> + auto CompareSections = [](const SecPtr &A, const SecPtr &B) {
> + return A->OriginalOffset < B->OriginalOffset;
> + };
> + std::stable_sort(std::begin(Sections), std::end(Sections),
> CompareSections);
> +}
> +
> +template <class ELFT> void Object<ELFT>::assignOffsets() {
> + // Decide file offsets and indexes.
> + size_t PhdrSize = Segments.size() * sizeof(Elf_Phdr);
> + // We can put section data after the ELF header and the program headers.
> + uint64_t Offset = sizeof(Elf_Ehdr) + PhdrSize;
> + uint64_t Index = 1;
> + for (auto &Section : Sections) {
> + // The segment can have a different alignment than the section. In
> the case
> + // that there is a parent segment then as long as we satisfy the
> alignment
> + // of the segment it should follow that that the section is aligned.
> + if (Section->ParentSegment) {
> + auto FirstInSeg = Section->ParentSegment->firstSection();
> + if (FirstInSeg == Section.get()) {
> + Offset = alignTo(Offset, Section->ParentSegment->Align);
> + // There can be gaps at the start of a segment before the first
> section.
> + // So first we assign the alignment of the segment and then
> assign the
> + // location of the section from there
> + Section->Offset =
> + Offset + Section->OriginalOffset -
> Section->ParentSegment->Offset;
> + }
> + // We should respect interstitial gaps of allocated sections. We
> *must*
> + // maintain the memory image so that addresses are preserved. As,
> with the
> + // exception of SHT_NOBITS sections at the end of segments, the
> memory
> + // image is a copy of the file image, we preserve the file image as
> well.
> + // There's a strange case where a thread local SHT_NOBITS can cause
> the
> + // memory image and file image to not be the same. This occurs, on
> some
> + // systems, when a thread local SHT_NOBITS is between two
> SHT_PROGBITS
> + // and the thread local SHT_NOBITS section is at the end of a TLS
> segment.
> + // In this case to faithfully copy the segment file image we must
> use
> + // relative offsets. In any other case this would be the same as
> using the
> + // relative addresses so this should maintian the memory image as
> desired.
> + Offset = FirstInSeg->Offset + Section->OriginalOffset -
> + FirstInSeg->OriginalOffset;
> + }
> + // Alignment should have already been handled by the above if
> statement if
> + // this if this section is in a segment. Technically this shouldn't do
> + // anything bad if the alignments of the sections are all correct and
> the
> + // file image isn't corrupted. Still in sticking with the motto
> "maintain
> + // the file image" we should avoid messing up the file image if the
> + // alignment disagrees with the file image.
> + if (!Section->ParentSegment && Section->Align)
> + Offset = alignTo(Offset, Section->Align);
> + Section->Offset = Offset;
> + Section->Index = Index++;
> + if (Section->Type != SHT_NOBITS)
> + Offset += Section->Size;
> + }
> + // 'offset' should now be just after all the section data so we should
> set the
> + // section header table offset to be exactly here. This spot might not
> be
> + // aligned properly however so we should align it as needed. For 32-bit
> ELF
> + // this needs to be 4-byte aligned and on 64-bit it needs to be 8-byte
> aligned
> + // so the size of ELFT::Addr is used to ensure this.
> + Offset = alignTo(Offset, sizeof(typename ELFT::Addr));
> + SHOffset = Offset;
> +}
> +
> +template <class ELFT> void Object<ELFT>::finalize() {
> + for (auto &Section : Sections)
> + SectionNames->addString(Section->Name);
> +
> + sortSections();
> + assignOffsets();
> +
> + // Finalize SectionNames first so that we can assign name indexes.
> + SectionNames->finalize();
> + // Finally now that all offsets and indexes have been set we can
> finalize any
> + // remaining issues.
> + uint64_t Offset = SHOffset + sizeof(Elf_Shdr);
> + for (auto &Section : Sections) {
> + Section->HeaderOffset = Offset;
> + Offset += sizeof(Elf_Shdr);
> + Section->NameIndex = SectionNames->findIndex(Section->Name);
> + Section->finalize();
> + }
> +
> + for (auto &Segment : Segments)
> + Segment->finalize();
> +}
> +
> +template <class ELFT>
> +void Object<ELFT>::writeHeader(FileOutputBuffer &Out) const {
> + uint8_t *Buf = Out.getBufferStart();
> + Elf_Ehdr &Ehdr = *reinterpret_cast<Elf_Ehdr *>(Buf);
> + std::copy(Ident, Ident + 16, Ehdr.e_ident);
> + Ehdr.e_type = Type;
> + Ehdr.e_machine = Machine;
> + Ehdr.e_version = Version;
> + Ehdr.e_entry = Entry;
> + Ehdr.e_phoff = sizeof(Elf_Ehdr);
> + Ehdr.e_shoff = SHOffset;
> + Ehdr.e_flags = Flags;
> + Ehdr.e_ehsize = sizeof(Elf_Ehdr);
> + Ehdr.e_phentsize = sizeof(Elf_Phdr);
> + Ehdr.e_phnum = Segments.size();
> + Ehdr.e_shentsize = sizeof(Elf_Shdr);
> + Ehdr.e_shnum = Sections.size() + 1;
> + Ehdr.e_shstrndx = SectionNames->Index;
> +}
> +
> +template <class ELFT>
> +void Object<ELFT>::writeProgramHeaders(FileOutputBuffer &Out) const {
> + for (auto &Phdr : Segments)
> + Phdr->template writeHeader<ELFT>(Out);
> +}
> +
> +template <class ELFT>
> +void Object<ELFT>::writeSectionHeaders(FileOutputBuffer &Out) const {
> + uint8_t *Buf = Out.getBufferStart() + SHOffset;
> + // This reference serves to write the dummy section header at the
> begining
> + // of the file.
> + Elf_Shdr &Shdr = *reinterpret_cast<Elf_Shdr *>(Buf);
> + Shdr.sh_name = 0;
> + Shdr.sh_type = SHT_NULL;
> + Shdr.sh_flags = 0;
> + Shdr.sh_addr = 0;
> + Shdr.sh_offset = 0;
> + Shdr.sh_size = 0;
> + Shdr.sh_link = 0;
> + Shdr.sh_info = 0;
> + Shdr.sh_addralign = 0;
> + Shdr.sh_entsize = 0;
> +
> + for (auto &Section : Sections)
> + Section->template writeHeader<ELFT>(Out);
> +}
> +
> +template <class ELFT>
> +void Object<ELFT>::writeSectionData(FileOutputBuffer &Out) const {
> + for (auto &Section : Sections)
> + Section->writeSection(Out);
> +}
> +
> +template <class ELFT> void Object<ELFT>::write(FileOutputBuffer &Out) {
> + writeHeader(Out);
> + writeProgramHeaders(Out);
> + writeSectionData(Out);
> + writeSectionHeaders(Out);
> +}
> +
> +template class Object<ELF64LE>;
> +template class Object<ELF64BE>;
> +template class Object<ELF32LE>;
> +template class Object<ELF32BE>;
>
> Added: llvm/trunk/tools/llvm-objcopy/Object.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-objcopy/Object.h?rev=308821&view=auto
>
> ==============================================================================
> --- llvm/trunk/tools/llvm-objcopy/Object.h (added)
> +++ llvm/trunk/tools/llvm-objcopy/Object.h Fri Jul 21 19:33:45 2017
> @@ -0,0 +1,150 @@
> +//===- Object.h -------------------------------------------------*- C++
> -*-===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is distributed under the University of Illinois Open Source
> +// License. See LICENSE.TXT for details.
> +//
>
> +//===----------------------------------------------------------------------===//
> +
> +#ifndef LLVM_OBJCOPY_OBJECT_H
> +#define LLVM_OBJCOPY_OBJECT_H
> +
> +#include "llvm/MC/StringTableBuilder.h"
> +#include "llvm/Object/ELFObjectFile.h"
> +#include "llvm/Support/FileOutputBuffer.h"
> +
> +#include <memory>
> +#include <set>
> +
> +class Segment;
> +
> +class SectionBase {
> +public:
> + llvm::StringRef Name;
> + Segment *ParentSegment = nullptr;
> + uint64_t HeaderOffset;
> + uint64_t OriginalOffset;
> + uint32_t Index;
> +
> + uint64_t Addr = 0;
> + uint64_t Align = 1;
> + uint32_t EntrySize = 0;
> + uint64_t Flags = 0;
> + uint64_t Info = 0;
> + uint64_t Link = llvm::ELF::SHN_UNDEF;
> + uint64_t NameIndex = 0;
> + uint64_t Offset = 0;
> + uint64_t Size = 0;
> + uint64_t Type = llvm::ELF::SHT_NULL;
> +
> + virtual ~SectionBase() {}
> + virtual void finalize();
> + template <class ELFT> void writeHeader(llvm::FileOutputBuffer &Out)
> const;
> + virtual void writeSection(llvm::FileOutputBuffer &Out) const = 0;
> +};
> +
> +class Segment {
> +private:
> + struct SectionCompare {
> + bool operator()(const SectionBase *Lhs, const SectionBase *Rhs) const
> {
> + // Some sections might have the same address if one of them is
> empty. To
> + // fix this we can use the lexicographic ordering on ->Addr and the
> + // address of the actully stored section.
> + if (Lhs->Addr == Rhs->Addr)
> + return Lhs < Rhs;
> + return Lhs->Addr < Rhs->Addr;
> + }
> + };
> +
> + std::set<const SectionBase *, SectionCompare> Sections;
> +
> +public:
> + uint64_t Align;
> + uint64_t FileSize;
> + uint32_t Flags;
> + uint32_t Index;
> + uint64_t MemSize;
> + uint64_t Offset;
> + uint64_t PAddr;
> + uint64_t Type;
> + uint64_t VAddr;
> +
> + void finalize();
> + const SectionBase *firstSection() const {
> + if (!Sections.empty())
> + return *Sections.begin();
> + return nullptr;
> + }
> + void addSection(const SectionBase *sec) { Sections.insert(sec); }
> + template <class ELFT> void writeHeader(llvm::FileOutputBuffer &Out)
> const;
> +};
> +
> +class Section : public SectionBase {
> +private:
> + llvm::ArrayRef<uint8_t> Contents;
> +
> +public:
> + Section(llvm::ArrayRef<uint8_t> Data) : Contents(Data) {}
> + void writeSection(llvm::FileOutputBuffer &Out) const override;
> +};
> +
> +// This is just a wraper around a StringTableBuilder that implements
> SectionBase
> +class StringTableSection : public SectionBase {
> +private:
> + llvm::StringTableBuilder StrTabBuilder;
> +
> +public:
> + StringTableSection() : StrTabBuilder(llvm::StringTableBuilder::ELF) {
> + Type = llvm::ELF::SHT_STRTAB;
> + }
> +
> + void addString(llvm::StringRef Name);
> + uint32_t findIndex(llvm::StringRef Name) const;
> + void finalize() override;
> + void writeSection(llvm::FileOutputBuffer &Out) const override;
> + static bool classof(const SectionBase *S) {
> + return S->Type == llvm::ELF::SHT_STRTAB;
> + }
> +};
> +
> +template <class ELFT> class Object {
> +private:
> + typedef std::unique_ptr<SectionBase> SecPtr;
> + typedef std::unique_ptr<Segment> SegPtr;
> +
> + typedef typename ELFT::Shdr Elf_Shdr;
> + typedef typename ELFT::Ehdr Elf_Ehdr;
> + typedef typename ELFT::Phdr Elf_Phdr;
> +
> + StringTableSection *SectionNames;
> + std::vector<SecPtr> Sections;
> + std::vector<SegPtr> Segments;
> +
> + void sortSections();
> + void assignOffsets();
> + SecPtr makeSection(const llvm::object::ELFFile<ELFT> &ElfFile,
> + const Elf_Shdr &Shdr);
> + void readProgramHeaders(const llvm::object::ELFFile<ELFT> &ElfFile);
> + void readSectionHeaders(const llvm::object::ELFFile<ELFT> &ElfFile);
> + void writeHeader(llvm::FileOutputBuffer &Out) const;
> + void writeProgramHeaders(llvm::FileOutputBuffer &Out) const;
> + void writeSectionData(llvm::FileOutputBuffer &Out) const;
> + void writeSectionHeaders(llvm::FileOutputBuffer &Out) const;
> +
> +public:
> + uint8_t Ident[16];
> + uint64_t Entry;
> + uint64_t SHOffset;
> + uint32_t Type;
> + uint32_t Machine;
> + uint32_t Version;
> + uint32_t Flags;
> +
> + Object(const llvm::object::ELFObjectFile<ELFT> &Obj);
> + size_t totalSize() const;
> + void finalize();
> + void write(llvm::FileOutputBuffer &Out);
> +};
> +
> +#endif
>
> Added: llvm/trunk/tools/llvm-objcopy/llvm-objcopy.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-objcopy/llvm-objcopy.cpp?rev=308821&view=auto
>
> ==============================================================================
> --- llvm/trunk/tools/llvm-objcopy/llvm-objcopy.cpp (added)
> +++ llvm/trunk/tools/llvm-objcopy/llvm-objcopy.cpp Fri Jul 21 19:33:45 2017
> @@ -0,0 +1,99 @@
> +//===- llvm-objcopy.cpp -----------------------------------------*- C++
> -*-===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is distributed under the University of Illinois Open Source
> +// License. See LICENSE.TXT for details.
> +//
>
> +//===----------------------------------------------------------------------===//
> +#include "llvm-objcopy.h"
> +#include "Object.h"
> +#include "llvm/Support/CommandLine.h"
> +#include "llvm/Support/FileOutputBuffer.h"
> +#include "llvm/Support/PrettyStackTrace.h"
> +#include "llvm/Support/Signals.h"
> +#include "llvm/Support/ToolOutputFile.h"
> +
> +#include <memory>
> +#include <string>
> +#include <system_error>
> +
> +using namespace llvm;
> +using namespace object;
> +using namespace ELF;
> +
> +// The name this program was invoked as.
> +static StringRef ToolName;
> +
> +namespace llvm {
> +
> +LLVM_ATTRIBUTE_NORETURN void error(Twine Message) {
> + errs() << ToolName << ": " << Message << ".\n";
> + errs().flush();
> + exit(1);
> +}
> +
> +LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, std::error_code
> EC) {
> + assert(EC);
> + errs() << ToolName << ": '" << File << "': " << EC.message() << ".\n";
> + exit(1);
> +}
> +
> +LLVM_ATTRIBUTE_NORETURN void reportError(StringRef File, llvm::Error E) {
> + assert(E);
> + std::string Buf;
> + raw_string_ostream OS(Buf);
> + logAllUnhandledErrors(std::move(E), OS, "");
> + OS.flush();
> + errs() << ToolName << ": '" << File << "': " << Buf;
> + exit(1);
> +}
> +}
> +
> +cl::opt<std::string> InputFilename(cl::Positional, cl::desc("<input>"));
> +cl::opt<std::string> OutputFilename(cl::Positional, cl::desc("<output>"),
> + cl::init("-"));
> +
> +void CopyBinary(const ELFObjectFile<ELF64LE> &ObjFile) {
> + std::unique_ptr<FileOutputBuffer> Buffer;
> + Object<ELF64LE> Obj{ObjFile};
> + Obj.finalize();
> + ErrorOr<std::unique_ptr<FileOutputBuffer>> BufferOrErr =
> + FileOutputBuffer::create(OutputFilename, Obj.totalSize(),
> + FileOutputBuffer::F_executable);
> + if (BufferOrErr.getError())
> + error("failed to open " + OutputFilename);
> + else
> + Buffer = std::move(*BufferOrErr);
> + std::error_code EC;
> + std::unique_ptr<tool_output_file> Out =
> + make_unique<tool_output_file>(OutputFilename.data(), EC,
> sys::fs::F_None);
> + if (EC)
> + report_fatal_error(EC.message());
> + Obj.write(*Buffer);
> + if (auto EC = Buffer->commit())
> + reportError(OutputFilename, EC);
> + Out->keep();
> +}
> +
> +int main(int argc, char **argv) {
> + // Print a stack trace if we signal out.
> + sys::PrintStackTraceOnErrorSignal(argv[0]);
> + PrettyStackTraceProgram X(argc, argv);
> + llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
> + cl::ParseCommandLineOptions(argc, argv, "llvm objcopy utility\n");
> + ToolName = argv[0];
> + if (InputFilename.empty()) {
> + cl::PrintHelpMessage();
> + return 2;
> + }
> + Expected<OwningBinary<Binary>> BinaryOrErr =
> createBinary(InputFilename);
> + if (!BinaryOrErr)
> + reportError(InputFilename, BinaryOrErr.takeError());
> + Binary &Binary = *BinaryOrErr.get().getBinary();
> + if (ELFObjectFile<ELF64LE> *o =
> dyn_cast<ELFObjectFile<ELF64LE>>(&Binary)) {
> + CopyBinary(*o);
> + return 0;
> + }
> + reportError(InputFilename, object_error::invalid_file_type);
> +}
>
> Added: llvm/trunk/tools/llvm-objcopy/llvm-objcopy.h
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-objcopy/llvm-objcopy.h?rev=308821&view=auto
>
> ==============================================================================
> --- llvm/trunk/tools/llvm-objcopy/llvm-objcopy.h (added)
> +++ llvm/trunk/tools/llvm-objcopy/llvm-objcopy.h Fri Jul 21 19:33:45 2017
> @@ -0,0 +1,32 @@
> +//===- llvm-objcopy.h -------------------------------------------*- C++
> -*-===//
> +//
> +// The LLVM Compiler Infrastructure
> +//
> +// This file is distributed under the University of Illinois Open Source
> +// License. See LICENSE.TXT for details.
> +//
>
> +//===----------------------------------------------------------------------===//
> +#ifndef LLVM_OBJCOPY_H
> +#define LLVM_OBJCOPY_H
> +
> +#include "llvm/ADT/Twine.h"
> +#include "llvm/Support/Error.h"
> +
> +namespace llvm {
> +
> +LLVM_ATTRIBUTE_NORETURN extern void error(Twine Message);
> +
> +// This is taken from llvm-readobj.
> +// [see here](llvm/tools/llvm-readobj/llvm-readobj.h:38)
> +template <class T> T unwrapOrError(Expected<T> EO) {
> + if (EO)
> + return *EO;
> + std::string Buf;
> + raw_string_ostream OS(Buf);
> + logAllUnhandledErrors(EO.takeError(), OS, "");
> + OS.flush();
> + error(Buf);
> +}
> +}
> +
> +#endif
>
>
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
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