[Support/ELF] - Added few constants and structs relative to compressed sections.

Patch adds few constants and structs to support compressed sections.

SHF_COMPRESSED intersects with platform specific XCORE_SHF_CP_SECTION,
both has value of 0x800U.

Reference link:
http://www.sco.com/developers/gabi/latest/ch4.sheader.html

Differential revision: http://reviews.llvm.org/D20209

llvm-svn: 269404

1 files changed, 27 insertions, 0 deletions

diff --git a/llvm/include/llvm/Support/ELF.h b/llvm/include/llvm/Support/ELF.h
index ef868ef075d..352fd8a5cde 100644
--- a/llvm/include/llvm/Support/ELF.h
+++ b/llvm/include/llvm/Support/ELF.h
@@ -740,6 +740,9 @@ enum : unsigned {
   // This section holds Thread-Local Storage.
   SHF_TLS = 0x400U,
 
+  // Identifies a section containing compressed data.
+  SHF_COMPRESSED = 0x800U,
+
   // This section is excluded from the final executable or shared library.
   SHF_EXCLUDE = 0x80000000U,
 
@@ -1315,6 +1318,30 @@ enum {
   NT_GNU_BUILD_ID = 3
 };
 
+// Compressed section header for ELF32.
+struct Elf32_Chdr {
+  Elf32_Word ch_type;
+  Elf32_Word ch_size;
+  Elf32_Word ch_addralign;
+};
+
+// Compressed section header for ELF64.
+struct Elf64_Chdr {
+  Elf64_Word ch_type;
+  Elf64_Word ch_reserved;
+  Elf64_Xword ch_size;
+  Elf64_Xword ch_addralign;
+};
+
+// Legal values for ch_type field of compressed section header.
+enum {
+  ELFCOMPRESS_ZLIB = 1,            // ZLIB/DEFLATE algorithm.
+  ELFCOMPRESS_LOOS = 0x60000000,   // Start of OS-specific.
+  ELFCOMPRESS_HIOS = 0x6fffffff,   // End of OS-specific.
+  ELFCOMPRESS_LOPROC = 0x70000000, // Start of processor-specific.
+  ELFCOMPRESS_HIPROC = 0x7fffffff  // End of processor-specific.
+};
+
 } // end namespace ELF
 
 } // end namespace llvm