diff --git a/src/link/Coff.zig b/src/link/Coff.zig index a87996001e..bcc507b02f 100644 --- a/src/link/Coff.zig +++ b/src/link/Coff.zig @@ -70,9 +70,10 @@ got_entries: std.ArrayListUnmanaged(Entry) = .{}, got_entries_free_list: std.ArrayListUnmanaged(u32) = .{}, got_entries_table: std.AutoHashMapUnmanaged(SymbolWithLoc, u32) = .{}, -imports: std.ArrayListUnmanaged(Entry) = .{}, -imports_free_list: std.ArrayListUnmanaged(u32) = .{}, -imports_table: std.AutoHashMapUnmanaged(SymbolWithLoc, u32) = .{}, +/// A table of ImportTables partitioned by the library name. +/// Key is an offset into the interning string table `temp_strtab`. +import_tables: std.AutoArrayHashMapUnmanaged(u32, ImportTable) = .{}, +imports_count_dirty: bool = true, /// Virtual address of the entry point procedure relative to image base. entry_addr: ?u32 = null, @@ -159,6 +160,92 @@ const Section = struct { free_list: std.ArrayListUnmanaged(Atom.Index) = .{}, }; +/// Represents an import table in the .idata section where each contained pointer +/// is to a symbol from the same DLL. +/// +/// The layout of .idata section is as follows: +/// +/// --- ADDR1 : IAT (all import tables concatenated together) +/// ptr +/// ptr +/// 0 sentinel +/// ptr +/// 0 sentinel +/// --- ADDR2: headers +/// ImportDirectoryEntry header +/// ImportDirectoryEntry header +/// sentinel +/// --- ADDR2: lookup tables +/// Lookup table +/// 0 sentinel +/// Lookup table +/// 0 sentinel +/// --- ADDR3: name hint tables +/// hint-symname +/// hint-symname +/// --- ADDR4: DLL names +/// DLL#1 name +/// DLL#2 name +/// --- END +const ImportTable = struct { + entries: std.ArrayListUnmanaged(SymbolWithLoc) = .{}, + free_list: std.ArrayListUnmanaged(u32) = .{}, + lookup: std.AutoHashMapUnmanaged(SymbolWithLoc, u32) = .{}, + index: u8, + + const ITable = @This(); + + fn deinit(itab: *ITable, allocator: Allocator) void { + itab.entries.deinit(allocator); + itab.free_list.deinit(allocator); + itab.lookup.deinit(allocator); + } + + fn size(itab: ITable) u32 { + return @intCast(u32, itab.entries.items.len) * @sizeOf(u64); + } + + fn addImport(itab: *ITable, allocator: Allocator, target: SymbolWithLoc) !u32 { + try itab.entries.ensureUnusedCapacity(allocator, 1); + const index: u32 = blk: { + if (itab.free_list.popOrNull()) |index| { + log.debug(" (reusing import entry index {d})", .{index}); + break :blk index; + } else { + log.debug(" (allocating import entry at index {d})", .{itab.entries.items.len}); + const index = @intCast(u32, itab.entries.items.len); + _ = itab.entries.addOneAssumeCapacity(); + break :blk index; + } + }; + itab.entries.items[index] = target; + try itab.lookup.putNoClobber(allocator, target, index); + return index; + } + + fn getBaseAddress(itab: *const ITable, coff_file: *const Coff) u32 { + const header = coff_file.sections.items(.header)[coff_file.idata_section_index.?]; + var addr = header.virtual_address; + for (coff_file.import_tables.values(), 0..) |other_itab, i| { + if (itab.index == i) break; + addr += @intCast(u32, other_itab.entries.items.len * @sizeOf(u64)) + 8; + } + return addr; + } + + pub fn getImportAddress(itab: *const ITable, coff_file: *const Coff, target: SymbolWithLoc) ?u32 { + const index = itab.lookup.get(target) orelse return null; + const base_vaddr = itab.getBaseAddress(coff_file); + return base_vaddr + index * @sizeOf(u64); + } + + pub fn write(itab: ITable, writer: anytype) !void { + for (itab.entries.items) |_| { + try writer.writeIntLittle(u64, 0); + } + } +}; + const DeclMetadata = struct { atom: Atom.Index, section: u16, @@ -315,9 +402,11 @@ pub fn deinit(self: *Coff) void { self.got_entries.deinit(gpa); self.got_entries_free_list.deinit(gpa); self.got_entries_table.deinit(gpa); - self.imports.deinit(gpa); - self.imports_free_list.deinit(gpa); - self.imports_table.deinit(gpa); + + for (self.import_tables.values()) |*itab| { + itab.deinit(gpa); + } + self.import_tables.deinit(gpa); { var it = self.decls.iterator(); @@ -730,28 +819,6 @@ pub fn allocateGotEntry(self: *Coff, target: SymbolWithLoc) !u32 { return index; } -pub fn allocateImportEntry(self: *Coff, target: SymbolWithLoc) !u32 { - const gpa = self.base.allocator; - try self.imports.ensureUnusedCapacity(gpa, 1); - - const index: u32 = blk: { - if (self.imports_free_list.popOrNull()) |index| { - log.debug(" (reusing import entry index {d})", .{index}); - break :blk index; - } else { - log.debug(" (allocating import entry at index {d})", .{self.imports.items.len}); - const index = @intCast(u32, self.imports.items.len); - _ = self.imports.addOneAssumeCapacity(); - break :blk index; - } - }; - - self.imports.items[index] = .{ .target = target, .sym_index = 0 }; - try self.imports_table.putNoClobber(gpa, target, index); - - return index; -} - pub fn createAtom(self: *Coff) !Atom.Index { const gpa = self.base.allocator; const atom_index = @intCast(Atom.Index, self.atoms.items.len); @@ -802,21 +869,6 @@ fn createGotAtom(self: *Coff, target: SymbolWithLoc) !Atom.Index { return atom_index; } -fn createImportAtom(self: *Coff) !Atom.Index { - const atom_index = try self.createAtom(); - const atom = self.getAtomPtr(atom_index); - atom.size = @sizeOf(u64); - atom.alignment = @alignOf(u64); - - const sym = atom.getSymbolPtr(self); - sym.section_number = @intToEnum(coff.SectionNumber, self.idata_section_index.? + 1); - sym.value = try self.allocateAtom(atom_index, atom.size, atom.alignment); - - log.debug("allocated import atom at 0x{x}", .{sym.value}); - - return atom_index; -} - fn growAtom(self: *Coff, atom_index: Atom.Index, new_atom_size: u32, alignment: u32) !u32 { const atom = self.getAtom(atom_index); const sym = atom.getSymbol(self); @@ -876,10 +928,8 @@ fn markRelocsDirtyByAddress(self: *Coff, addr: u32) void { var it = self.relocs.valueIterator(); while (it.next()) |relocs| { for (relocs.items) |*reloc| { - const target_atom_index = reloc.getTargetAtomIndex(self) orelse continue; - const target_atom = self.getAtom(target_atom_index); - const target_sym = target_atom.getSymbol(self); - if (target_sym.value < addr) continue; + const target_vaddr = reloc.getTargetAddress(self) orelse continue; + if (target_vaddr < addr) continue; reloc.dirty = true; } } @@ -1468,35 +1518,42 @@ pub fn flushModule(self: *Coff, comp: *Compilation, prog_node: *std.Progress.Nod sub_prog_node.activate(); defer sub_prog_node.end(); + const gpa = self.base.allocator; + while (self.unresolved.popOrNull()) |entry| { assert(entry.value); // We only expect imports generated by the incremental linker for now. const global = self.globals.items[entry.key]; - if (self.imports_table.contains(global)) continue; - - const import_index = try self.allocateImportEntry(global); - const import_atom_index = try self.createImportAtom(); - const import_atom = self.getAtom(import_atom_index); - self.imports.items[import_index].sym_index = import_atom.getSymbolIndex().?; - try self.writePtrWidthAtom(import_atom_index); - } - - if (build_options.enable_logging) { - self.logSymtab(); + const sym = self.getSymbol(global); + const res = try self.import_tables.getOrPut(gpa, sym.value); + const itable = res.value_ptr; + if (!res.found_existing) { + itable.* = .{ .index = @intCast(u8, self.import_tables.values().len - 1) }; + } + if (itable.lookup.contains(global)) continue; + // TODO: we could technically write the pointer placeholder for to-be-bound import here, + // but since this happens in flush, there is currently no point. + _ = try itable.addImport(gpa, global); + self.imports_count_dirty = true; } + try self.writeImportTables(); { var it = self.relocs.keyIterator(); while (it.next()) |atom| { try self.resolveRelocs(atom.*); } } - try self.writeImportTable(); try self.writeBaseRelocations(); if (self.getEntryPoint()) |entry_sym_loc| { self.entry_addr = self.getSymbol(entry_sym_loc).value; } + if (build_options.enable_logging) { + self.logSymtab(); + self.logImportTables(); + } + try self.writeStrtab(); try self.writeDataDirectoriesHeaders(); try self.writeSectionHeaders(); @@ -1660,53 +1717,36 @@ fn writeBaseRelocations(self: *Coff) !void { }; } -fn writeImportTable(self: *Coff) !void { +fn writeImportTables(self: *Coff) !void { if (self.idata_section_index == null) return; + if (!self.imports_count_dirty) return; const gpa = self.base.allocator; - const last_atom_index = self.sections.items(.last_atom_index)[self.idata_section_index.?] orelse return; + const ext = ".dll"; const header = &self.sections.items(.header)[self.idata_section_index.?]; - const last_atom = self.getAtom(last_atom_index); - const iat_rva = header.virtual_address; - const iat_size = last_atom.getSymbol(self).value + last_atom.size * 2 - iat_rva; // account for sentinel zero pointer - - const dll_name = "KERNEL32.dll"; - - var import_dir_entry = coff.ImportDirectoryEntry{ - .import_lookup_table_rva = @sizeOf(coff.ImportDirectoryEntry) * 2, - .time_date_stamp = 0, - .forwarder_chain = 0, - .name_rva = 0, - .import_address_table_rva = iat_rva, - }; - - // TODO: we currently assume there's only one (implicit) DLL - ntdll - var lookup_table = std.ArrayList(coff.ImportLookupEntry64.ByName).init(gpa); - defer lookup_table.deinit(); - - var names_table = std.ArrayList(u8).init(gpa); - defer names_table.deinit(); - - // TODO: check if import is still valid - for (self.imports.items) |entry| { - const target_name = self.getSymbolName(entry.target); - const start = names_table.items.len; - mem.writeIntLittle(u16, try names_table.addManyAsArray(2), 0); // TODO: currently, hint is set to 0 as we haven't yet parsed any DLL - try names_table.appendSlice(target_name); - try names_table.append(0); - const end = names_table.items.len; - if (!mem.isAlignedGeneric(usize, end - start, @sizeOf(u16))) { - try names_table.append(0); + // Calculate needed size + var iat_size: u32 = 0; + var dir_table_size: u32 = @sizeOf(coff.ImportDirectoryEntry); // sentinel + var lookup_table_size: u32 = 0; + var names_table_size: u32 = 0; + var dll_names_size: u32 = 0; + for (self.import_tables.keys(), 0..) |off, i| { + const lib_name = self.temp_strtab.getAssumeExists(off); + const itable = self.import_tables.values()[i]; + iat_size += itable.size() + 8; + dir_table_size += @sizeOf(coff.ImportDirectoryEntry); + lookup_table_size += @intCast(u32, itable.entries.items.len + 1) * @sizeOf(coff.ImportLookupEntry64.ByName); + for (itable.entries.items) |entry| { + const sym_name = self.getSymbolName(entry); + names_table_size += 2 + mem.alignForwardGeneric(u32, @intCast(u32, sym_name.len + 1), 2); } - try lookup_table.append(.{ .name_table_rva = @intCast(u31, start) }); + dll_names_size += @intCast(u32, lib_name.len + ext.len + 1); } - try lookup_table.append(.{ .name_table_rva = 0 }); // the sentinel - const dir_entry_size = @sizeOf(coff.ImportDirectoryEntry) + lookup_table.items.len * @sizeOf(coff.ImportLookupEntry64.ByName) + names_table.items.len + dll_name.len + 1; + const needed_size = iat_size + dir_table_size + lookup_table_size + names_table_size + dll_names_size; const sect_capacity = self.allocatedSize(header.pointer_to_raw_data); - const needed_size = @intCast(u32, iat_size + dir_entry_size + @sizeOf(coff.ImportDirectoryEntry)); if (needed_size > sect_capacity) { const new_offset = self.findFreeSpace(needed_size, default_file_alignment); log.debug("moving .idata from 0x{x} to 0x{x}", .{ header.pointer_to_raw_data, new_offset }); @@ -1716,41 +1756,105 @@ fn writeImportTable(self: *Coff) !void { if (needed_size > sect_vm_capacity) { try self.growSectionVM(self.idata_section_index.?, needed_size); } + + header.virtual_size = @max(header.virtual_size, needed_size); + header.size_of_raw_data = needed_size; } - // Fixup offsets - const base_rva = iat_rva + iat_size; - import_dir_entry.import_lookup_table_rva += base_rva; - import_dir_entry.name_rva = @intCast(u32, base_rva + dir_entry_size + @sizeOf(coff.ImportDirectoryEntry) - dll_name.len - 1); - - for (lookup_table.items[0 .. lookup_table.items.len - 1]) |*lk| { - lk.name_table_rva += @intCast(u31, base_rva + @sizeOf(coff.ImportDirectoryEntry) * 2 + lookup_table.items.len * @sizeOf(coff.ImportLookupEntry64.ByName)); - } - + // Do the actual writes var buffer = std.ArrayList(u8).init(gpa); defer buffer.deinit(); - try buffer.ensureTotalCapacity(dir_entry_size + @sizeOf(coff.ImportDirectoryEntry)); - buffer.appendSliceAssumeCapacity(mem.asBytes(&import_dir_entry)); - buffer.appendNTimesAssumeCapacity(0, @sizeOf(coff.ImportDirectoryEntry)); // the sentinel; TODO: I think doing all of the above on bytes directly might be cleaner - buffer.appendSliceAssumeCapacity(mem.sliceAsBytes(lookup_table.items)); - buffer.appendSliceAssumeCapacity(names_table.items); - buffer.appendSliceAssumeCapacity(dll_name); - buffer.appendAssumeCapacity(0); + try buffer.ensureTotalCapacityPrecise(needed_size); + buffer.resize(needed_size) catch unreachable; - try self.base.file.?.pwriteAll(buffer.items, header.pointer_to_raw_data + iat_size); - // Override the IAT atoms - // TODO: we should rewrite only dirtied atoms, but that's for way later - try self.base.file.?.pwriteAll(mem.sliceAsBytes(lookup_table.items), header.pointer_to_raw_data); + const dir_header_size = @sizeOf(coff.ImportDirectoryEntry); + const lookup_entry_size = @sizeOf(coff.ImportLookupEntry64.ByName); + + var iat_offset: u32 = 0; + var dir_table_offset = iat_size; + var lookup_table_offset = dir_table_offset + dir_table_size; + var names_table_offset = lookup_table_offset + lookup_table_size; + var dll_names_offset = names_table_offset + names_table_size; + for (self.import_tables.keys(), 0..) |off, i| { + const lib_name = self.temp_strtab.getAssumeExists(off); + const itable = self.import_tables.values()[i]; + + // Lookup table header + const lookup_header = coff.ImportDirectoryEntry{ + .import_lookup_table_rva = header.virtual_address + lookup_table_offset, + .time_date_stamp = 0, + .forwarder_chain = 0, + .name_rva = header.virtual_address + dll_names_offset, + .import_address_table_rva = header.virtual_address + iat_offset, + }; + mem.copy(u8, buffer.items[dir_table_offset..], mem.asBytes(&lookup_header)); + dir_table_offset += dir_header_size; + + for (itable.entries.items) |entry| { + const import_name = self.getSymbolName(entry); + + // IAT and lookup table entry + const lookup = coff.ImportLookupEntry64.ByName{ .name_table_rva = @intCast(u31, header.virtual_address + names_table_offset) }; + mem.copy(u8, buffer.items[iat_offset..], mem.asBytes(&lookup)); + iat_offset += lookup_entry_size; + mem.copy(u8, buffer.items[lookup_table_offset..], mem.asBytes(&lookup)); + lookup_table_offset += lookup_entry_size; + + // Names table entry + mem.writeIntLittle(u16, buffer.items[names_table_offset..][0..2], 0); // Hint set to 0 until we learn how to parse DLLs + names_table_offset += 2; + mem.copy(u8, buffer.items[names_table_offset..], import_name); + names_table_offset += @intCast(u32, import_name.len); + buffer.items[names_table_offset] = 0; + names_table_offset += 1; + if (!mem.isAlignedGeneric(usize, names_table_offset, @sizeOf(u16))) { + buffer.items[names_table_offset] = 0; + names_table_offset += 1; + } + } + + // IAT sentinel + mem.writeIntLittle(u64, buffer.items[iat_offset..][0..lookup_entry_size], 0); + iat_offset += 8; + + // Lookup table sentinel + mem.copy(u8, buffer.items[lookup_table_offset..], mem.asBytes(&coff.ImportLookupEntry64.ByName{ .name_table_rva = 0 })); + lookup_table_offset += lookup_entry_size; + + // DLL name + mem.copy(u8, buffer.items[dll_names_offset..], lib_name); + dll_names_offset += @intCast(u32, lib_name.len); + mem.copy(u8, buffer.items[dll_names_offset..], ext); + dll_names_offset += @intCast(u32, ext.len); + buffer.items[dll_names_offset] = 0; + dll_names_offset += 1; + } + + // Sentinel + const lookup_header = coff.ImportDirectoryEntry{ + .import_lookup_table_rva = 0, + .time_date_stamp = 0, + .forwarder_chain = 0, + .name_rva = 0, + .import_address_table_rva = 0, + }; + mem.copy(u8, buffer.items[dir_table_offset..], mem.asBytes(&lookup_header)); + dir_table_offset += dir_header_size; + + assert(dll_names_offset == needed_size); + + try self.base.file.?.pwriteAll(buffer.items, header.pointer_to_raw_data); self.data_directories[@enumToInt(coff.DirectoryEntry.IMPORT)] = .{ - .virtual_address = iat_rva + iat_size, - .size = @intCast(u32, @sizeOf(coff.ImportDirectoryEntry) * 2), + .virtual_address = header.virtual_address + iat_size, + .size = dir_table_size, }; - self.data_directories[@enumToInt(coff.DirectoryEntry.IAT)] = .{ - .virtual_address = iat_rva, + .virtual_address = header.virtual_address, .size = iat_size, }; + + self.imports_count_dirty = false; } fn writeStrtab(self: *Coff) !void { @@ -2139,14 +2243,6 @@ pub fn getGotAtomIndexForSymbol(self: *const Coff, sym_loc: SymbolWithLoc) ?Atom return self.getAtomIndexForSymbol(.{ .sym_index = got_entry.sym_index, .file = null }); } -/// Returns import atom that references `sym_loc` if one exists. -/// Returns null otherwise. -pub fn getImportAtomIndexForSymbol(self: *const Coff, sym_loc: SymbolWithLoc) ?Atom.Index { - const imports_index = self.imports_table.get(sym_loc) orelse return null; - const imports_entry = self.imports.items[imports_index]; - return self.getAtomIndexForSymbol(.{ .sym_index = imports_entry.sym_index, .file = null }); -} - fn setSectionName(self: *Coff, header: *coff.SectionHeader, name: []const u8) !void { if (name.len <= 8) { mem.copy(u8, &header.name, name); @@ -2267,3 +2363,19 @@ fn logSections(self: *Coff) void { }); } } + +fn logImportTables(self: *const Coff) void { + log.debug("import tables:", .{}); + for (self.import_tables.keys(), 0..) |off, i| { + const lib_name = self.temp_strtab.getAssumeExists(off); + const itable = self.import_tables.values()[i]; + log.debug("IAT({s}) @{x}:", .{ lib_name, itable.getBaseAddress(self) }); + for (itable.entries.items, 0..) |entry, j| { + log.debug(" {d}@{?x} => {s}", .{ + j, + itable.getImportAddress(self, entry), + self.getSymbolName(entry), + }); + } + } +} diff --git a/src/link/Coff/Relocation.zig b/src/link/Coff/Relocation.zig index 1ba1d7a1c1..5dcb0552fc 100644 --- a/src/link/Coff/Relocation.zig +++ b/src/link/Coff/Relocation.zig @@ -45,23 +45,25 @@ pcrel: bool, length: u2, dirty: bool = true, -/// Returns an Atom which is the target node of this relocation edge (if any). -pub fn getTargetAtomIndex(self: Relocation, coff_file: *const Coff) ?Atom.Index { +/// Returns address of the target if any. +pub fn getTargetAddress(self: Relocation, coff_file: *const Coff) ?u32 { switch (self.type) { - .got, - .got_page, - .got_pageoff, - => return coff_file.getGotAtomIndexForSymbol(self.target), + .got, .got_page, .got_pageoff, .direct, .page, .pageoff => { + const maybe_target_atom_index = switch (self.type) { + .got, .got_page, .got_pageoff => coff_file.getGotAtomIndexForSymbol(self.target), + .direct, .page, .pageoff => coff_file.getAtomIndexForSymbol(self.target), + else => unreachable, + }; + const target_atom_index = maybe_target_atom_index orelse return null; + const target_atom = coff_file.getAtom(target_atom_index); + return target_atom.getSymbol(coff_file).value; + }, - .direct, - .page, - .pageoff, - => return coff_file.getAtomIndexForSymbol(self.target), - - .import, - .import_page, - .import_pageoff, - => return coff_file.getImportAtomIndexForSymbol(self.target), + .import, .import_page, .import_pageoff => { + const sym = coff_file.getSymbol(self.target); + const itab = coff_file.import_tables.get(sym.value) orelse return null; + return itab.getImportAddress(coff_file, self.target); + }, } } @@ -73,9 +75,7 @@ pub fn resolve(self: *Relocation, atom_index: Atom.Index, coff_file: *Coff) !voi const file_offset = source_section.pointer_to_raw_data + source_sym.value - source_section.virtual_address; - const target_atom_index = self.getTargetAtomIndex(coff_file) orelse return; - const target_atom = coff_file.getAtom(target_atom_index); - const target_vaddr = target_atom.getSymbol(coff_file).value; + const target_vaddr = self.getTargetAddress(coff_file) orelse return; const target_vaddr_with_addend = target_vaddr + self.addend; log.debug(" ({x}: [() => 0x{x} ({s})) ({s}) (in file at 0x{x})", .{