Make sure we use symbol flags to detect thumbness.

[sas]

Summary

This was GetAddressClass' behavior before. This is required when
debugging binaries that don't have mapping symbols ($a, $t, etc). These
binaries will only have the lower bit of the address set in the symbol
table.

[clayborg]

You should populate the m_address_class_map in ObjectFileELF::ParseSymbols() as this is where the m_address_class_map is already being populated. For ARM symbols, just check the flags and add an appropriate entry. Then this code doesn't need to exist here, but be moved into ObjectFileELF::ParseSymbols().

[clayborg]

See Inlined comment.

source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

975–997

Remove this and move it to ObjectFileELF::ParseSymbols()

[tberghammer]

source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

2191–2213

The function you are looking for is already implemented here (in the way Greg suggested). If it isn't working in your case then you should try to figure out why it isn't working in the way it is intended.

[sas]

Ok I'll integrate that with the code that uses m_address_class_map.

[sas]

Not required anymore.

source/Plugins/ObjectFile/ELF/ObjectFileELF.cpp

ObjectFileELF::GetAddressClass (addr_t file_addr)
 
     auto res = ObjectFile::GetAddressClass (file_addr);
     if (res != eAddressClassCode)
         return res;
 
     auto ub = m_address_class_map.upper_bound(file_addr);
     if (ub == m_address_class_map.begin())
     {
-        // No entry in the address class map before the address. Return
-        // default address class for an address in a code section.
-        return eAddressClassCode;
+        // No entry in the address class map before the address. Try finding
+        // the address class by using symbol flags, otherwise return default
+        // address class for an address in a code section.
+
+        ArchSpec arch_spec;
+        GetArchitecture(arch_spec);
+        if (arch_spec.GetMachine() != llvm::Triple::arm)
+            return res;
+
+        auto symtab = GetSymtab();
+        if (symtab == nullptr)
+            return res;
+
+        auto symbol = symtab->FindSymbolContainingFileAddress(file_addr);
+        if (symbol == nullptr)
+            return res;
+
+        // Thumb symbols have the lower bit set in the flags field so we just check
+        // for that.
+        if (symbol->GetFlags() & ARM_ELF_SYM_IS_THUMB)
+            res = eAddressClassCodeAlternateISA;
+
+        return res;
     }
 
     // Move iterator to the address class entry preceding address
     --ub;
 
     return ub->second;
 }
 
for (i = 0; i < num_symbols; ++i)
                                 break;
                         }
                     }
                     if (mapping_symbol)
                         continue;
                 }
             }
 
             if (arch.GetMachine() == llvm::Triple::arm)
             {
                 if (symbol_type == eSymbolTypeCode)
                 {
                     if (symbol.st_value & 1)
                     {
                         // Subtracting 1 from the address effectively unsets
                         // the low order bit, which results in the address
                         // actually pointing to the beginning of the symbol.
                         // This delta will be used below in conjunction with
                         // symbol.st_value to produce the final symbol_value
                         // that we store in the symtab.
                         symbol_value_offset = -1;
                         additional_flags = ARM_ELF_SYM_IS_THUMB;
                         m_address_class_map[symbol.st_value^1] = eAddressClassCodeAlternateISA;
                     }
                     else
                     {
                         // This address is ARM
                         m_address_class_map[symbol.st_value] = eAddressClassCode;
                     }
                 }
             }
 
             /*
              * MIPS:
              * The bit #0 of an address is used for ISA mode (1 for microMIPS, 0 for MIPS).
              * This allows processer to switch between microMIPS and MIPS without any need
              * for special mode-control register. However, apart from .debug_line, none of
              * the ELF/DWARF sections set the ISA bit (for symbol or section). Use st_other
              * flag to check whether the symbol is microMIPS and then set the address class