Ejemplo n.º 1
0
        public void RunScript(binary_library.IBinaryFile output, IList <binary_library.IBinaryFile> inputs)
        {
            // First, identify the maximum sizes of common symbols
            Dictionary <string, SizeAlign> comm_syms = new Dictionary <string, SizeAlign>();

            foreach (var iput in inputs)
            {
                var comm = iput.GetCommonSection();
                if (comm != null)
                {
                    for (int i = 0; i < comm.GetSymbolCount(); i++)
                    {
                        var comm_sym = comm.GetSymbol(i);
                        if (comm_sym != null)
                        {
                            string name = comm_sym.Name;
                            if (comm_sym.Type == SymbolType.Local)
                            {
                                name = iput.Filename + "." + name;
                            }
                            if (!comm_syms.ContainsKey(name) ||
                                comm_syms[name].Size < comm_sym.Size)
                            {
                                comm_syms[name] = new SizeAlign {
                                    Size = (int)comm_sym.Size, Align = (int)comm_sym.Offset, Sym = comm_sym
                                }
                            }
                            ;
                        }
                    }
                }
            }
            int comm_len = 0;

            foreach (var k in comm_syms)
            {
                if ((comm_len % k.Value.Align) != 0)
                {
                    comm_len = (comm_len / k.Value.Align) * k.Value.Align + k.Value.Align;
                }
                comm_len += k.Value.Size;
            }

            // Run the script
            LinkerScriptState state = new LinkerScriptState();

            state.comm_length = comm_len;
            state.cur_section = output.GetGlobalSection();
            foreach (ScriptEntry se in Script)
            {
                se.DoCommand(output, inputs, state);
            }

            if (Program.is_reloc)
            {
                output.IsExecutable = false;
            }
            else
            {
                output.IsExecutable = true;
            }

            Dictionary <string, int> globl_syms = new Dictionary <string, int>();
            int sym_idx = 0;

            if (output.IsExecutable)
            {
                // Resolve weak symbols
                while (sym_idx < output.GetSymbolCount())
                {
                    ISymbol sym = output.GetSymbol(sym_idx);
                    if (sym.Type == SymbolType.Weak)
                    {
                        // Whether to promote to a global symbol
                        bool for_removal = false;

                        // Have we found the appropriate global symbol before?
                        if (globl_syms.ContainsKey(sym.Name))
                        {
                            for_removal = true;  // for removal
                        }
                        else
                        {
                            // Search from here onwards looking for a global
                            //  symbol with the same name
                            for (int sym_idx_2 = sym_idx; sym_idx_2 < output.GetSymbolCount(); sym_idx_2++)
                            {
                                ISymbol sym_2 = output.GetSymbol(sym_idx_2);
                                if (sym_2.Type == SymbolType.Global &&
                                    sym_2.Name == sym.Name)
                                {
                                    globl_syms[sym.Name] = sym_idx_2;
                                    for_removal          = true;
                                    break;
                                }
                            }
                        }

                        if (for_removal)
                        {
                            output.RemoveSymbol(sym_idx);
                            continue;
                        }
                        else
                        {
                            // Promote to a global symbol
                            sym.Type             = SymbolType.Global;
                            globl_syms[sym.Name] = sym_idx;
                        }
                    }
                    else if (sym.Type == SymbolType.Global)
                    {
                        globl_syms[sym.Name] = sym_idx;
                    }

                    sym_idx++;
                }

                // Resolve common symbols.  If a global symbol is defined for
                //  this, we use that, else we allocate a space in bss for it
                ulong cur_comm_sym_offset = state.comm_offset;
                foreach (var k in comm_syms.Keys)
                {
                    if (!globl_syms.ContainsKey(k))
                    {
                        // define a symbol in the common section for this
                        if (state.comm_sect == null)
                        {
                            throw new Exception("Common sections used but no common section defined in linker script");
                        }

                        uint align = (uint)comm_syms[k].Align;
                        if ((cur_comm_sym_offset % align) != 0)
                        {
                            cur_comm_sym_offset = (cur_comm_sym_offset / align) * align + align;
                        }

                        ISymbol comm_sym = comm_syms[k].Sym;
                        //comm_sym.DefinedIn = state.comm_sect;
                        comm_sym.Offset      = cur_comm_sym_offset;
                        comm_sym.Name        = k;
                        cur_comm_sym_offset += (uint)comm_syms[k].Size;
                    }
                }
            }

            // Now iterate through the data, saving to the appropriate sections
            foreach (KeyValuePair <binary_library.ISection, List <byte> > kvp in state.data)
            {
                if (kvp.Key != null)
                {
                    if (kvp.Key.HasData)
                    {
                        kvp.Key.Length = kvp.Value.Count;
                        for (int i = 0; i < kvp.Value.Count; i++)
                        {
                            kvp.Key.Data[i] = kvp.Value[i];
                        }
                    }
                }
            }

            // Resolve relocations
            foreach (IBinaryFile ifile in inputs)
            {
                int reloc_count = ifile.GetRelocationCount();
                for (int i = 0; i < reloc_count; i++)
                {
                    IRelocation reloc = ifile.GetRelocation(i);

                    // Is the location of the relocation included in the output?
                    if (state.included_sections.Contains(reloc.DefinedIn))
                    {
                        if (output.IsExecutable == false)
                        {
                            // Create a new relocation for the output file
                            IRelocation new_copy_reloc = output.CreateRelocation();
                            new_copy_reloc.DefinedIn  = state.input_section_locations[reloc.DefinedIn].OutputSection;
                            new_copy_reloc.Offset     = reloc.Offset + state.input_section_locations[reloc.DefinedIn].OutputSectionOffset;
                            new_copy_reloc.Addend     = reloc.Addend;
                            new_copy_reloc.References = reloc.References;
                            new_copy_reloc.Type       = reloc.Type;
                            output.AddRelocation(new_copy_reloc);
                            continue;
                        }
                        // Where is the value to be relocated?
                        LinkerScriptState.InputSectionLocation isl = state.input_section_locations[reloc.DefinedIn];

                        // Get the target of the relocation
                        ISymbol  reloc_target          = reloc.References;
                        ISection target_section        = null;
                        ulong    target_section_offset = 0;
                        if (reloc_target.DefinedIn == null)
                        {
                            // Try and find the requested symbol
                            ISymbol found_target = output.FindSymbol(reloc_target.Name);
                            if (found_target == null)
                            {
                                throw new Exception("Label '" + reloc_target.Name + "' not found");
                            }

                            target_section        = found_target.DefinedIn;
                            target_section_offset = found_target.Offset;
                        }
                        else if (reloc_target.DefinedIn == reloc_target.DefinedIn.File.GetCommonSection())
                        {
                            // Get full name of symbol
                            string name = reloc_target.Name;
                            if (reloc_target.Type == SymbolType.Local)
                            {
                                name = reloc_target.DefinedIn.File.Filename + "." + name;
                            }
                            target_section = state.comm_sect;

                            if (globl_syms.ContainsKey(name))
                            {
                                ISymbol found_target = output.FindSymbol(reloc_target.Name);
                                if (found_target == null)
                                {
                                    throw new Exception("Label '" + reloc_target.Name + "' not found");
                                }

                                target_section        = found_target.DefinedIn;
                                target_section_offset = found_target.Offset;
                            }
                            else
                            {
                                target_section        = state.comm_sect;
                                target_section_offset = reloc_target.Offset;
                            }
                        }
                        else
                        {
                            // Use the one stored in the relocation
                            // First find out where the input section is located in the output
                            if (!state.included_sections.Contains(reloc_target.DefinedIn))
                            {
                                throw new Exception();
                            }
                            LinkerScriptState.InputSectionLocation target_isl = state.input_section_locations[reloc_target.DefinedIn];
                            target_section        = target_isl.OutputSection;
                            target_section_offset = target_isl.OutputSectionOffset + reloc_target.Offset;
                        }

                        // Create a new relocation for the output file
                        IRelocation new_reloc = output.CreateRelocation();
                        new_reloc.DefinedIn         = isl.OutputSection;
                        new_reloc.Offset            = isl.OutputSectionOffset + reloc.Offset;
                        new_reloc.Addend            = reloc.Addend;
                        new_reloc.References        = output.CreateSymbol();
                        new_reloc.References.Offset = target_section_offset;
                        new_reloc.References.Size   = reloc_target.Size;
                        new_reloc.References.Name   = reloc_target.Name;
                        target_section.AddSymbol(new_reloc.References);
                        new_reloc.Type = reloc.Type;

                        // Evaluate the relocation
                        long val = new_reloc.Type.Evaluate(new_reloc);

                        // Does it fit in the provided space?
                        bool  fits     = true;
                        ulong uval     = BitConverter.ToUInt64(BitConverter.GetBytes(val), 0);
                        var   t        = new_reloc.Type;
                        ulong ext_mask = 0xffffffffffffffffUL << (t.BitLength + t.BitOffset);
                        if ((t.BitLength + t.BitOffset) >= 64)
                        {
                            ext_mask = 0;
                        }
                        if (new_reloc.Type.IsSigned)
                        {
                            var sign_bit = (uval >> (t.BitLength + t.BitOffset - 1)) & 0x1;
                            if (sign_bit == 1 && (uval & ext_mask) != ext_mask)
                            {
                                fits = false;
                            }
                            else if (sign_bit == 0 && (uval & ext_mask) != 0)
                            {
                                fits = false;
                            }
                        }
                        else if ((uval & ext_mask) != 0)
                        {
                            fits = false;
                        }
                        if (fits == false)
                        {
                            throw new Exception("Relocation truncated to fit: " +
                                                reloc_target.Name + " against " +
                                                t.Name);
                        }

                        // Build the new value to reinsert in the data stream
                        byte[] orig = new byte[8];
                        for (int idx = 0; idx < new_reloc.Type.Length; idx++)
                        {
                            orig[idx] = new_reloc.DefinedIn.Data[(int)new_reloc.Offset + idx];
                        }
                        ulong orig_val = BitConverter.ToUInt64(orig, 0);

                        // Mask out those bits we don't want
                        orig_val &= new_reloc.Type.KeepMask;

                        // Only set those bits we want
                        uval &= new_reloc.Type.SetMask;
                        uval |= orig_val;

                        byte[] uvalb = BitConverter.GetBytes(uval);
                        for (int idx = 0; idx < new_reloc.Type.Length; idx++)
                        {
                            new_reloc.DefinedIn.Data[(int)new_reloc.Offset + idx] = uvalb[idx];
                        }
                    }
                }
            }

            // Remove local and undefined symbols from the output file
            sym_idx = 0;
            while (sym_idx < output.GetSymbolCount())
            {
                ISymbol sym = output.GetSymbol(sym_idx);
                if (sym.Type == SymbolType.Local || sym.Type == SymbolType.Undefined)
                {
                    output.RemoveSymbol(sym_idx);
                }
                else
                {
                    sym_idx++;
                }
            }
        }