From d53951d2ef7e3883a51680958b95d35a360c6562 Mon Sep 17 00:00:00 2001 From: Petr Hosek Date: Fri, 4 Aug 2017 23:18:18 +0000 Subject: [llvm][llvm-objcopy] When outputting to binary don't output segments that cover no sections Sometimes LLD will produce a PT_LOAD segment that only covers the headers (and covers no sections). GNU objcopy does not output the segment contents for these sections. In particular this is an issue in building magenta because the final link step for the kernel would produce just such a PT_LOAD segment. This change is to support this case and to match what GNU objcopy does in this case. Patch by Jake Ehrlich Differential Revision: https://reviews.llvm.org/D36196 llvm-svn: 310149 --- llvm/tools/llvm-objcopy/Object.cpp | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) (limited to 'llvm/tools/llvm-objcopy') diff --git a/llvm/tools/llvm-objcopy/Object.cpp b/llvm/tools/llvm-objcopy/Object.cpp index 576f660bd98..adb25435a5b 100644 --- a/llvm/tools/llvm-objcopy/Object.cpp +++ b/llvm/tools/llvm-objcopy/Object.cpp @@ -354,7 +354,10 @@ template size_t BinaryObject::totalSize() const { template void BinaryObject::write(FileOutputBuffer &Out) const { for (auto &Segment : this->Segments) { - if (Segment->Type == llvm::ELF::PT_LOAD) { + // GNU objcopy does not output segments that do not cover a section. Such + // segments can sometimes be produced by LLD due to how LLD handles PT_PHDR. + if (Segment->Type == llvm::ELF::PT_LOAD && + Segment->firstSection() != nullptr) { Segment->writeSegment(Out); } } @@ -373,7 +376,8 @@ template void BinaryObject::finalize() { uint64_t Offset = 0; for (auto &Segment : this->Segments) { - if (Segment->Type == llvm::ELF::PT_LOAD) { + if (Segment->Type == llvm::ELF::PT_LOAD && + Segment->firstSection() != nullptr) { Offset = alignTo(Offset, Segment->Align); Segment->Offset = Offset; Offset += Segment->FileSize; -- cgit v1.2.3