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[llvm-objcopy] Use SHT_NOTE for added note sections. 

Summary:
Fix llvm-objcopy to add .note sections as SHT_NOTEs. GNU objcopy overrides section flags for special sections. For `.note` sections (with the exception of `.note.GNU-stack`), SHT_NOTE is used.

Many other sections are special cased by libbfd, but `.note` is the only special section I can seem to find being used with objcopy --add-section.

See `.note` in context of the full list of special sections here: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=blob;f=bfd/elf.c;h=eb3e1828e9c651678b95a1dcbc3b124783d1d2be;hb=HEAD#l2675

Reviewers: jhenderson, alexshap, jakehehrlich, espindola

Reviewed By: jhenderson

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D56570

llvm-svn: 351204
This commit is contained in:
Jordan Rupprecht 2019-01-15 16:57:23 +00:00
parent b8f08c8d7b
commit 17dd4a2c5e
3 changed files with 71 additions and 9 deletions
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36
llvm/test/tools/llvm-objcopy/ELF/add-note.test Normal file
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@ -0,0 +1,36 @@
# Verify that --add-section can be used to add a note section which is
# successfully interpreted by tools that read notes.
# Add [namesz, descsz, type, name, desc] for a build id.
# RUN: echo -e -n "\x04\x00\x00\x00" > %t-note.bin
# RUN: echo -e -n "\x10\x00\x00\x00" >> %t-note.bin
# RUN: echo -e -n "\x03\x00\x00\x00" >> %t-note.bin
# RUN: echo -e -n "GNU\x00" >> %t-note.bin
# RUN: echo -e -n "\x00\x01\x02\x03" >> %t-note.bin
# RUN: echo -e -n "\x04\x05\x06\x07" >> %t-note.bin
# RUN: echo -e -n "\x08\x09\x0a\x0b" >> %t-note.bin
# RUN: echo -e -n "\x0c\x0d\x0e\x0f" >> %t-note.bin
# RUN: yaml2obj %s > %t.o
# RUN: llvm-objcopy --add-section=.note.gnu.build-id=%t-note.bin %t.o %t-with-note.o
# RUN: llvm-readobj --notes %t-with-note.o | FileCheck %s
!ELF
FileHeader:
Class: ELFCLASS64
Data: ELFDATA2LSB
Type: ET_REL
Machine: EM_X86_64
# CHECK: Notes [
# CHECK-NEXT: NoteSection {
# CHECK-NEXT: Offset:
# CHECK-NEXT: Size:
# CHECK-NEXT: Note {
# CHECK-NEXT: Owner: GNU
# CHECK-NEXT: Data size: 0x10
# CHECK-NEXT: Type: NT_GNU_BUILD_ID
# CHECK-NEXT: Build ID: 000102030405060708090a0b0c0d0e0f
# CHECK-NEXT: }
# CHECK-NEXT: }
# CHECK-NEXT: ]

22
llvm/test/tools/llvm-objcopy/ELF/add-section-special.test Normal file
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@ -0,0 +1,22 @@
# Check the properties of added sections.
# By default, sections are SHT_PROGBITS, but .note sections (excluding
# .note.GNU-stack) are SHT_NOTE sections.
# RUN: yaml2obj %s > %t.o
# RUN: llvm-objcopy --add-section=.foo=/dev/null %t.o %t-foo.o
# RUN: llvm-objcopy --add-section=.note.foo=/dev/null %t.o %t-regular-note.o
# RUN: llvm-objcopy --add-section=.note.GNU-stack=/dev/null %t.o %t-gnu-stack.o
# RUN: llvm-readelf --sections %t-foo.o | FileCheck %s --check-prefix=NORMAL
# RUN: llvm-readelf --sections %t-regular-note.o | FileCheck %s --check-prefix=NOTE
# RUN: llvm-readelf --sections %t-gnu-stack.o | FileCheck %s --check-prefix=GNU-STACK
!ELF
FileHeader:
Class: ELFCLASS64
Data: ELFDATA2LSB
Type: ET_REL
Machine: EM_X86_64
# NORMAL: .foo PROGBITS
# NOTE: .note.foo NOTE
# GNU-STACK: .note.GNU-stack PROGBITS

22
llvm/tools/llvm-objcopy/ELF/ELFObjcopy.cpp
View File

@ -499,17 +499,21 @@ static void handleArgs(const CopyConfig &Config, Object &Obj,
if (!Config.AddSection.empty()) {
for (const auto &Flag : Config.AddSection) {
auto SecPair = Flag.split("=");
auto SecName = SecPair.first;
auto File = SecPair.second;
auto BufOrErr = MemoryBuffer::getFile(File);
std::pair<StringRef, StringRef> SecPair = Flag.split("=");
StringRef SecName = SecPair.first;
StringRef File = SecPair.second;
ErrorOr<std::unique_ptr<MemoryBuffer>> BufOrErr =
MemoryBuffer::getFile(File);
if (!BufOrErr)
reportError(File, BufOrErr.getError());
auto Buf = std::move(*BufOrErr);
auto BufPtr = reinterpret_cast<const uint8_t *>(Buf->getBufferStart());
auto BufSize = Buf->getBufferSize();
Obj.addSection<OwnedDataSection>(SecName,
ArrayRef<uint8_t>(BufPtr, BufSize));
std::unique_ptr<MemoryBuffer> Buf = std::move(*BufOrErr);
ArrayRef<uint8_t> Data(
reinterpret_cast<const uint8_t *>(Buf->getBufferStart()),
Buf->getBufferSize());
OwnedDataSection &NewSection =
Obj.addSection<OwnedDataSection>(SecName, Data);
if (SecName.startswith(".note") && SecName != ".note.GNU-stack")
NewSection.Type = SHT_NOTE;
}
}