Parse .note.android.ident header from elf files

[tberghammer]

Summary

Parse .note.android.ident header from elf files

In android a .note.android.ident section header is added to the elf
files to provide information for the debuggers that it is an android
specific module. This CL add logic to parse it out from the elf files
and set the module specification based on it.

[clayborg]

Looks good.

lldb/trunk/source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

 
 namespace {
 
 // ELF note owner definitions
 const char *const LLDB_NT_OWNER_FREEBSD = "FreeBSD";
 const char *const LLDB_NT_OWNER_GNU     = "GNU";
 const char *const LLDB_NT_OWNER_NETBSD  = "NetBSD";
 const char *const LLDB_NT_OWNER_CSR     = "csr";
+const char *const LLDB_NT_OWNER_ANDROID = "Android";
 
 // ELF note type definitions
 const elf_word LLDB_NT_FREEBSD_ABI_TAG  = 0x01;
 const elf_word LLDB_NT_FREEBSD_ABI_SIZE = 4;
 
 const elf_word LLDB_NT_GNU_ABI_TAG      = 0x01;
 const elf_word LLDB_NT_GNU_ABI_SIZE     = 16;
 
while (true)
             // It could provide a steer towards the kalimba variant which
             // this ELF targets.
             if(note.n_descsz)
             {
                 const char *cstr = data.GetCStr(&offset, llvm::RoundUpToAlignment (note.n_descsz, 4));
                 (void)cstr;
             }
         }
+        else if (note.n_name == LLDB_NT_OWNER_ANDROID)
+        {
+            arch_spec.GetTriple().setOS(llvm::Triple::OSType::Linux);
+            arch_spec.GetTriple().setEnvironment(llvm::Triple::EnvironmentType::Android);
+        }
 
         if (!processed)
             offset += llvm::RoundUpToAlignment(note.n_descsz, 4);
     }
 
     return error;
 }
 
if (strtab_idx && strtab_idx < section_headers.size())
                         lldb::offset_t gnu_debuglink_offset = 0;
                         gnu_debuglink_file = data.GetCStr (&gnu_debuglink_offset);
                         gnu_debuglink_offset = llvm::RoundUpToAlignment (gnu_debuglink_offset, 4);
                         data.GetU32 (&gnu_debuglink_offset, &gnu_debuglink_crc, 1);
                     }
                 }
 
                 // Process ELF note section entries.
-                if (header.sh_type == SHT_NOTE)
+                bool is_note_header = (header.sh_type == SHT_NOTE);
+
+                // The section header ".note.android.ident" is stored as a
+                // PROGBITS type header but it is actually a note header.
+                static ConstString g_sect_name_android_ident (".note.android.ident");
+                if (!is_note_header && name == g_sect_name_android_ident)
+                    is_note_header = true;
+
+                if (is_note_header)
                 {
                     // Allow notes to refine module info.
                     DataExtractor data;
                     if (section_size && (data.SetData (object_data, header.sh_offset, section_size) == section_size))
                     {
                         Error error = RefineModuleDetailsFromNote (data, arch_spec, uuid);
                         if (error.Fail ())
                         {