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 --- lib/Object/ELFYAML.cpp | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'lib/Object') diff --git a/lib/Object/ELFYAML.cpp b/lib/Object/ELFYAML.cpp index c396f66ee6..547720ddc3 100644 --- a/lib/Object/ELFYAML.cpp +++ b/lib/Object/ELFYAML.cpp @@ -658,6 +658,7 @@ static void commonSectionMapping(IO &IO, ELFYAML::Section &Section) { static void sectionMapping(IO &IO, ELFYAML::RawContentSection &Section) { commonSectionMapping(IO, Section); IO.mapOptional("Content", Section.Content); + IO.mapOptional("Size", Section.Size, Hex64(Section.Content.binary_size())); } static void sectionMapping(IO &IO, ELFYAML::RelocationSection &Section) { @@ -687,6 +688,14 @@ void MappingTraits>::mapping( } } +StringRef MappingTraits>::validate( + IO &io, std::unique_ptr &Section) { + const auto *RawSection = dyn_cast(Section.get()); + if (!RawSection || RawSection->Size >= RawSection->Content.binary_size()) + return StringRef(); + return "Section size must be greater or equal to the content size"; +} + void MappingTraits::mapping(IO &IO, ELFYAML::Relocation &Rel) { IO.mapRequired("Offset", Rel.Offset); -- cgit v1.2.3