From 19ab8f850f2937915598958b7c54957eed1a94c5 Mon Sep 17 00:00:00 2001 From: Simon Atanasyan Date: Fri, 16 May 2014 16:01:00 +0000 Subject: [yaml2obj][ELF] Add an optional `Size` field to the YAML section declaration. Now the only method to configure ELF section's content and size is to assign a hexadecimal string to the `Content` field. Unfortunately this way is completely useless when you need to declare a really large section. To solve this problem this patch adds one more optional field `Size` to the `RawContentSection` structure. When yaml2obj generates an ELF file it uses the following algorithm: 1. If both `Content` and `Size` fields are missed create an empty section. 2. If only `Content` field is missed take section length from the `Size` field and fill the section by zero. 3. If only `Size` field is missed create a section using data from the `Content` field. 4. If both `Content` and `Size` fields are provided validate that the `Size` value is not less than size of `Content` data. Than take section length from the `Size`, fill beginning of the section by `Content` and the rest by zero. Examples -------- * Create a section 0x10000 bytes long filled by zero Name: .data Type: SHT_PROGBITS Flags: [ SHF_ALLOC ] Size: 0x10000 * Create a section 0x10000 bytes long starting from 'CA' 'FE' 'BA' 'BE' Name: .data Type: SHT_PROGBITS Flags: [ SHF_ALLOC ] Content: CAFEBABE Size: 0x10000 The patch reviewed by Michael Spencer. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208995 91177308-0d34-0410-b5e6-96231b3b80d8 --- tools/yaml2obj/yaml2elf.cpp | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'tools/yaml2obj') diff --git a/tools/yaml2obj/yaml2elf.cpp b/tools/yaml2obj/yaml2elf.cpp index 3190b27d32..bb52cda7c1 100644 --- a/tools/yaml2obj/yaml2elf.cpp +++ b/tools/yaml2obj/yaml2elf.cpp @@ -314,9 +314,14 @@ void ELFState::writeSectionContent(Elf_Shdr &SHeader, const ELFYAML::RawContentSection &Section, ContiguousBlobAccumulator &CBA) { - Section.Content.writeAsBinary(CBA.getOSAndAlignedOffset(SHeader.sh_offset)); + assert(Section.Size >= Section.Content.binary_size() && + "Section size and section content are inconsistent"); + raw_ostream &OS = CBA.getOSAndAlignedOffset(SHeader.sh_offset); + Section.Content.writeAsBinary(OS); + for (auto i = Section.Content.binary_size(); i < Section.Size; ++i) + OS.write(0); SHeader.sh_entsize = 0; - SHeader.sh_size = Section.Content.binary_size(); + SHeader.sh_size = Section.Size; } template -- cgit v1.2.3