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author | Simon Atanasyan <simon@atanasyan.com> | 2014-05-16 16:01:00 +0000 |
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committer | Simon Atanasyan <simon@atanasyan.com> | 2014-05-16 16:01:00 +0000 |
commit | 19ab8f850f2937915598958b7c54957eed1a94c5 (patch) | |
tree | 9b58523f685b0ba1fdc815c7789cbd76eb67b74c /tools/yaml2obj | |
parent | b32cee560d91bb2ec4325ad348ee322a42a3a3cf (diff) | |
download | llvm-19ab8f850f2937915598958b7c54957eed1a94c5.tar.gz llvm-19ab8f850f2937915598958b7c54957eed1a94c5.tar.bz2 llvm-19ab8f850f2937915598958b7c54957eed1a94c5.tar.xz |
[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
Diffstat (limited to 'tools/yaml2obj')
-rw-r--r-- | tools/yaml2obj/yaml2elf.cpp | 9 |
1 files changed, 7 insertions, 2 deletions
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<ELFT>::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 <class ELFT> |