SuccessChanges

Summary

  1. [yaml2obj] - Add a support for defining null sections in YAMLs. ELF spec shows (Figure 4-10: Section Header Table Entry:Index 0, http://www.sco.com/developers/gabi/latest/ch4.sheader.html) that section header at index 0 (null section) can have sh_size and sh_link fields set to non-zero values. It says (https://docs.oracle.com/cd/E19683-01/817-3677/6mj8mbtc9/index.html): "If the number of sections is greater than or equal to SHN_LORESERVE (0xff00), this member has the value zero and the actual number of section header table entries is contained in the sh_size field of the section header at index 0. Otherwise, the sh_size member of the initial entry contains 0." and: "If the section name string table section index is greater than or equal to SHN_LORESERVE (0xff00), this member has the value SHN_XINDEX (0xffff) and the actual index of the section name string table section is contained in the sh_link field of the section header at index 0. Otherwise, the sh_link member of the initial entry contains 0." At this moment it is not possible to create custom section headers at index 0 using yaml2obj. This patch implements this. Differential revision: https://reviews.llvm.org/D64913
Revision 366794 by grimar:
[yaml2obj] - Add a support for defining null sections in YAMLs.

ELF spec shows (Figure 4-10: Section Header Table Entry:Index 0,
http://www.sco.com/developers/gabi/latest/ch4.sheader.html)
that section header at index 0 (null section) can have sh_size and
sh_link fields set to non-zero values.

It says (https://docs.oracle.com/cd/E19683-01/817-3677/6mj8mbtc9/index.html):

"If the number of sections is greater than or equal to SHN_LORESERVE (0xff00),
this member has the value zero and the actual number of section header table
entries is contained in the sh_size field of the section header at index 0.
Otherwise, the sh_size member of the initial entry contains 0."

and:

"If the section name string table section index is greater than or equal to SHN_LORESERVE
(0xff00), this member has the value SHN_XINDEX (0xffff) and the actual index of the section
name string table section is contained in the sh_link field of the section header at index 0.
Otherwise, the sh_link member of the initial entry contains 0."

At this moment it is not possible to create custom section headers at index 0 using yaml2obj.

This patch implements this.

Differential revision: https://reviews.llvm.org/D64913
Change TypePath in RepositoryPath in Workspace
The file was added/llvm/trunk/test/tools/yaml2obj/elf-custom-null-section.yamlllvm.src/test/tools/yaml2obj/elf-custom-null-section.yaml
The file was modified/llvm/trunk/tools/yaml2obj/yaml2elf.cpp (diff)llvm.src/tools/yaml2obj/yaml2elf.cpp