Commit fe0ad8d6e9
Changed files (1)
src-self-hosted
link
src-self-hosted/link/Coff.zig
@@ -1,6 +1,7 @@
const Coff = @This();
const std = @import("std");
+const log = std.log.scoped(.link);
const Allocator = std.mem.Allocator;
const assert = std.debug.assert;
const fs = std.fs;
@@ -9,12 +10,9 @@ const Module = @import("../Module.zig");
const codegen = @import("../codegen/wasm.zig");
const link = @import("../link.zig");
-
pub const base_tag: link.File.Tag = .coff;
const msdos_stub = @embedFile("msdos-stub.bin");
-const coff_file_header_offset = msdos_stub.len + 4;
-const optional_header_offset = coff_file_header_offset + 20;
base: link.File,
ptr_width: enum { p32, p64 },
@@ -70,8 +68,7 @@ fn openFile(allocator: *Allocator, file: fs.File, options: link.Options) !Coff {
/// Returns an error if `file` is not already open with +read +write +seek abilities.
fn createFile(allocator: *Allocator, file: fs.File, options: link.Options) !Coff {
switch (options.output_mode) {
- .Exe => {},
- .Obj => return error.TODOImplementWritingObjFiles, // @TODO DO OBJ FILES
+ .Exe, .Obj => {},
.Lib => return error.TODOImplementWritingLibFiles,
}
var self: Coff = .{
@@ -91,108 +88,205 @@ fn createFile(allocator: *Allocator, file: fs.File, options: link.Options) !Coff
};
errdefer self.deinit();
- var output = self.base.file.?.writer();
+ var coff_file_header_offset: u32 = 0;
+ if (options.output_mode == .Exe) {
+ // Write the MS-DOS stub and the PE signature
+ try self.base.file.?.pwriteAll(msdos_stub ++ "PE\x00\x00", 0);
+ coff_file_header_offset = msdos_stub.len + 4;
+ }
+
+ // COFF file header
+ const data_directory_count = 0;
+ var hdr_data: [112 + data_directory_count * 8 + 2 * 40]u8 = undefined;
+ var index: usize = 0;
- // MS-DOS stub + PE magic
- try output.writeAll(msdos_stub ++ "PE\x00\x00");
+ // @TODO Add an enum(u16) in std.coff, add .toCoffMachine to Arch
const machine_type: u16 = switch (self.base.options.target.cpu.arch) {
- .x86_64 => 0x8664,
- .i386 => 0x014c,
+ .x86_64 => 0x8664,
+ .i386 => 0x014c,
.riscv32 => 0x5032,
.riscv64 => 0x5064,
else => return error.UnsupportedCOFFArchitecture,
};
+ std.mem.writeIntLittle(u16, hdr_data[0..2], machine_type);
+ index += 2;
+
+ // Number of sections (we only use .got, .text)
+ std.mem.writeIntLittle(u16, hdr_data[index..][0..2], 2);
+ index += 2;
+ // TimeDateStamp (u32), PointerToSymbolTable (u32), NumberOfSymbols (u32)
+ std.mem.set(u8, hdr_data[index..][0..12], 0);
+ index += 12;
+
+ const optional_header_size = switch (options.output_mode) {
+ .Exe => data_directory_count * 8 + switch (self.ptr_width) {
+ .p32 => @as(u16, 96),
+ .p64 => 112,
+ },
+ else => 0,
+ };
+ std.mem.writeIntLittle(u16, hdr_data[index..][0..2], optional_header_size);
+ index += 2;
- // Start of COFF file header
- try output.writeIntLittle(u16, machine_type);
- try output.writeIntLittle(u16, switch (self.ptr_width) {
- .p32 => @as(u16, 98),
- .p64 => 114,
- });
- try output.writeAll("\x00" ** 14);
- // Characteristics - IMAGE_FILE_RELOCS_STRIPPED | IMAGE_FILE_EXECUTABLE_IMAGE | IMAGE_FILE_DEBUG_STRIPPED
- var characteristics: u16 = 0x0001 | 0x000 | 0x02002; // @TODO Remove debug info stripped flag when necessary
+ // Characteristics - IMAGE_FILE_DEBUG_STRIPPED
+ var characteristics: u16 = 0x200; // TODO Remove debug info stripped flag when necessary
+ if (options.output_mode == .Exe) {
+ // IMAGE_FILE_EXECUTABLE_IMAGE
+ characteristics |= 0x2;
+ }
switch (self.ptr_width) {
// IMAGE_FILE_32BIT_MACHINE
- .p32 => characteristics |= 0x0100,
+ .p32 => characteristics |= 0x100,
// IMAGE_FILE_LARGE_ADDRESS_AWARE
- .p64 => characteristics |= 0x0020,
- }
- try output.writeIntLittle(u16, characteristics);
- try output.writeIntLittle(u16, switch (self.ptr_width) {
- .p32 => @as(u16, 0x10b),
- .p64 => 0x20b,
- });
-
- // Start of optional header
- // TODO Linker version, use 0.0 for now.
- try output.writeAll("\x00" ** 2);
- // Zero out every field until "BaseOfCode"
- // @TODO Actually write entry point address, base of code address
- try output.writeAll("\x00" ** 20);
- switch (self.ptr_width) {
- .p32 => {
- // Zero out base of data
- try output.writeAll("\x00" ** 4);
- // Write image base
- try output.writeIntLittle(u32, 0x40000000);
- },
- .p64 => {
- // Write image base
- try output.writeIntLittle(u64, 0x40000000);
- },
+ .p64 => characteristics |= 0x20,
}
+ std.mem.writeIntLittle(u16, hdr_data[index..][0..2], characteristics);
+ index += 2;
- // Section alignment - default to 256
- try output.writeIntLittle(u32, 256);
- // File alignment - default to 512
- try output.writeIntLittle(u32, 512);
- // TODO - Minimum required windows version - use 6.0 (aka vista for now)
- try output.writeIntLittle(u16, 0x6);
- try output.writeIntLittle(u16, 0x0);
- // TODO - Image version - use 0.0 for now
- try output.writeIntLittle(u32, 0x0);
- // Subsystem version
- try output.writeIntLittle(u16, 0x6);
- try output.writeIntLittle(u16, 0x0);
- // Reserved zeroes
- try output.writeIntLittle(u32, 0x0);
- // Size of image - initialize to zero
- try output.writeIntLittle(u32, 0x0);
- // @TODO Size of headers - calculate this.
- try output.writeIntLittle(u32, 0x0);
- // Checksum
- try output.writeIntLittle(u32, 0x0);
- // Subsystem
- try output.writeIntLittle(u16, 0x3);
- // @TODO Dll characteristics, just using a value from a LLVM produced executable for now.
- try output.writeIntLittle(u16, 0x8160);
- switch (self.ptr_width) {
- .p32 => {
- // Stack reserve
- try output.writeIntLittle(u32, 0x1000000);
- // Stack commit
- try output.writeIntLittle(u32, 0x1000);
- // Heap reserve
- try output.writeIntLittle(u32, 0x100000);
- // Heap commit
- try output.writeIntLittle(u32, 0x100);
- },
- .p64 => {
- // Stack reserve
- try output.writeIntLittle(u64, 0x1000000);
- // Stack commit
- try output.writeIntLittle(u64, 0x1000);
- // Heap reserve
- try output.writeIntLittle(u64, 0x100000);
- // Heap commit
- try output.writeIntLittle(u64, 0x100);
- },
+ assert(index == 20);
+ try self.base.file.?.pwriteAll(hdr_data[0..index], coff_file_header_offset);
+
+ if (options.output_mode == .Exe) {
+ // Optional header
+ index = 0;
+ std.mem.writeIntLittle(u16, hdr_data[0..2], switch (self.ptr_width) {
+ .p32 => @as(u16, 0x10b),
+ .p64 => 0x20b,
+ });
+ index += 2;
+
+ // Linker version (u8 + u8), SizeOfCode (u32), SizeOfInitializedData (u32), SizeOfUninitializedData (u32), AddressOfEntryPoint (u32)
+ std.mem.set(u8, hdr_data[index..][0..18], 0);
+ index += 18;
+
+ // Base of code relative to the image base
+ // @TODO Check where to put this
+ std.mem.writeIntLittle(u32, hdr_data[index..][0..4], 0x1000);
+ index += 4;
+
+ if (self.ptr_width == .p32) {
+ // Base of data relative to the image base
+ std.mem.set(u8, hdr_data[index..][0..4], 0);
+ index += 4;
+
+ // Image base address
+ std.mem.writeIntLittle(u32, hdr_data[index..][0..4], 0x400_000);
+ index += 4;
+ } else {
+ // Image base address
+ std.mem.writeIntLittle(u64, hdr_data[index..][0..8], 0x140_000_000);
+ index += 8;
+ }
+
+ // Section alignment
+ std.mem.writeIntLittle(u32, hdr_data[index..][0..4], 4096);
+ index += 4;
+ // File alignment
+ std.mem.writeIntLittle(u32, hdr_data[index..][0..4], 512);
+ index += 4;
+ // Required OS version, 6.0 is vista
+ std.mem.writeIntLittle(u16, hdr_data[index..][0..2], 6);
+ index += 2;
+ std.mem.writeIntLittle(u16, hdr_data[index..][0..2], 0);
+ index += 2;
+ // Image version
+ std.mem.set(u8, hdr_data[index..][0..4], 0);
+ index += 4;
+ // Required subsystem version, same as OS version
+ std.mem.writeIntLittle(u16, hdr_data[index..][0..2], 6);
+ index += 2;
+ std.mem.writeIntLittle(u16, hdr_data[index..][0..2], 0);
+ index += 2;
+ // Reserved zeroes (u32), SizeOfImage (u32), SizeOfHeaders (u32), CheckSum (u32)
+ std.mem.set(u8, hdr_data[index..][0..16], 0);
+ index += 16;
+ // Subsystem, TODO: Let users specify the subsystem, always CUI for now
+ std.mem.writeIntLittle(u16, hdr_data[index..][0..2], 3);
+ index += 2;
+ // DLL characteristics, TODO: For now we are just using IMAGE_DLLCHARACTERISTICS_DYNAMIC_BASE
+ std.mem.writeIntLittle(u16, hdr_data[index..][0..2], 0x40);
+ index += 2;
+
+ switch (self.ptr_width) {
+ .p32 => {
+ // @TODO See llvm output for 32 bit executables
+ // Size of stack reserve + commit
+ std.mem.writeIntLittle(u32, hdr_data[index..][0..4], 0x1_000_000);
+ index += 4;
+ std.mem.writeIntLittle(u32, hdr_data[index..][0..4], 0x1_000);
+ index += 4;
+ // Size of heap reserve + commit
+ std.mem.writeIntLittle(u32, hdr_data[index..][0..4], 0x100_000);
+ index += 4;
+ std.mem.writeIntLittle(u32, hdr_data[index..][0..4], 0x1_000);
+ index += 4;
+ },
+ .p64 => {
+ // Size of stack reserve + commit
+ std.mem.writeIntLittle(u64, hdr_data[index..][0..8], 0x1_000_000);
+ index += 8;
+ std.mem.writeIntLittle(u64, hdr_data[index..][0..8], 0x1_000);
+ index += 8;
+ // Size of heap reserve + commit
+ std.mem.writeIntLittle(u64, hdr_data[index..][0..8], 0x100_000);
+ index += 8;
+ std.mem.writeIntLittle(u64, hdr_data[index..][0..8], 0x1_000);
+ index += 8;
+ },
+ }
+
+ // Reserved zeroes
+ std.mem.set(u8, hdr_data[index..][0..4], 0);
+ index += 4;
+
+ // Number of data directories
+ std.mem.writeIntLittle(u32, hdr_data[index..][0..4], data_directory_count);
+ index += 4;
+ // @TODO Write meaningful stuff here
+ // Initialize data directories to zero
+ std.mem.set(u8, hdr_data[index..][0..data_directory_count * 8], 0);
+ index += data_directory_count * 8;
+
+ assert(index == optional_header_size);
}
- // Reserved loader flags
- try output.writeIntLittle(u32, 0x0);
- // Number of RVA + sizes
- try output.writeIntLittle(u32, 0x0);
+
+ // @TODO Merge this write with the one above
+ const section_table_offset = coff_file_header_offset + 20 + optional_header_size;
+
+ // Write section table.
+ // First, the .got section
+ hdr_data[index..][0..8].* = ".got\x00\x00\x00\x00".*;
+ index += 8;
+ // Virtual size (u32) (@TODO Set to initial value in image files, zero otherwise), Virtual address (u32) (@TODO Set to value in image files, zero otherwise), Size of raw data (u32)
+ std.mem.set(u8, hdr_data[index..][0..12], 0);
+ index += 12;
+ // File pointer to the start of the section
+ std.mem.writeIntLittle(u32, hdr_data[index..][0..4], section_table_offset + 2 * 40);
+ index += 4;
+ // Pointer to relocations (u32) (@TODO Initialize this for object files), PointerToLinenumbers (u32), NumberOfRelocations (u16), (@TODO Initialize this for object files), NumberOfLinenumbers (u16)
+ std.mem.set(u8, hdr_data[index..][0..12], 0);
+ index += 12;
+ // Characteristics `IMAGE_SCN_CNT_INITIALIZED_DATA | IMAGE_SCN_MEM_READ = 0x40000040`
+ std.mem.writeIntLittle(u32, hdr_data[index..][0..4], 0x40000040);
+ index += 4;
+ // Then, the .text section
+ hdr_data[index..][0..8].* = ".text\x00\x00\x00".*;
+ index += 8;
+ // Virtual size (u32) (@TODO Set to initial value in image files, zero otherwise), Virtual address (u32) (@TODO Set to value in image files, zero otherwise), Size of raw data (u32)
+ std.mem.set(u8, hdr_data[index..][0..12], 0);
+ index += 12;
+ // File pointer to the start of the section (@TODO Add the initial size of .got)
+ std.mem.writeIntLittle(u32, hdr_data[index..][0..4], section_table_offset + 2 * 40);
+ index += 4;
+ // Pointer to relocations (u32) (@TODO Initialize this for object files), PointerToLinenumbers (u32), NumberOfRelocations (u16), (@TODO Initialize this for object files), NumberOfLinenumbers (u16)
+ std.mem.set(u8, hdr_data[index..][0..12], 0);
+ index += 12;
+ // Characteristics `IMAGE_SCN_CNT_CODE | IMAGE_SCN_MEM_EXECUTE | IMAGE_SCN_MEM_READ | IMAGE_SCN_MEM_WRITE = 0xE0000020`
+ std.mem.writeIntLittle(u32, hdr_data[index..][0..4], 0xE0000020);
+ index += 4;
+
+ assert(index == optional_header_size + 2 * 40);
+ try self.base.file.?.pwriteAll(hdr_data[0..index], coff_file_header_offset + 20);
return self;
}