Skip oatdata and oatexec symbols in system@[e-mail]

[tberghammer]

Summary

Skip oatdata and oatexec symbols in system@[e-mail]

On Android the oatdata and the oatexec symbols in system@[e-mail] covers the full .text
section what causes issues with displaying unusable symbol name to the user and very slow unwinding
speed because the instruction emulation based unwind plans try to emulate all instructions in these
symbols. Don't add these symbols to the symbol list as they have no use for the debugger and they
are causing a lot of trouble.

[ovyalov]

LGTM

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

ObjectFileELF::ParseSymbols (Symtab *symtab,
 
     static ConstString data_section_name(".data");
     static ConstString rodata_section_name(".rodata");
     static ConstString rodata1_section_name(".rodata1");
     static ConstString data2_section_name(".data1");
     static ConstString bss_section_name(".bss");
     static ConstString opd_section_name(".opd");    // For ppc64
 
-    //StreamFile strm(stdout, false);
+    // On Android the oatdata and the oatexec symbols in system@[e-mail] covers the full
+    // .text section what causes issues with displaying unusable symbol name to the user and very
+    // slow unwinding speed because the instruction emulation based unwind plans try to emulate all
+    // instructions in these symbols. Don't add these symbols to the symbol list as they have no
+    // use for the debugger and they are causing a lot of trouble.
+    // Filtering can't be restricted to Android because this special object file don't contain the
+    // note section specifying the environment to Android but the custom extension and file name
+    // makes it highly unlikely that this will collide with anything else.
+    bool skip_oatdata_oatexec = m_file.GetFilename() == ConstString("system@[e-mail]");
+
     unsigned i;
     for (i = 0; i < num_symbols; ++i)
     {
         if (symbol.Parse(symtab_data, &offset) == false)
             break;
         
         const char *symbol_name = strtab_data.PeekCStr(symbol.st_name);
 
         // No need to add non-section symbols that have no names
         if (symbol.getType() != STT_SECTION &&
             (symbol_name == NULL || symbol_name[0] == '\0'))
             continue;
 
-        //symbol.Dump (&strm, i, &strtab_data, section_list);
+        // Skipping oatdata and oatexec sections if it is requested. See details above the
+        // definition of skip_oatdata_oatexec for the reasons.
+        if (skip_oatdata_oatexec && (::strcmp(symbol_name, "oatdata") == 0 || ::strcmp(symbol_name, "oatexec") == 0))
+            continue;
 
         SectionSP symbol_section_sp;
         SymbolType symbol_type = eSymbolTypeInvalid;
         Elf64_Half symbol_idx = symbol.st_shndx;
 
         switch (symbol_idx)
         {
         case SHN_ABS: