zig/src-self-hosted/link.zig
Alexandros Naskos e9807418e7 Added .pe ObjectFormat
MachO linker no longer collects unused dwarf debug information
2020-09-04 05:22:26 +03:00

280 lines
11 KiB
Zig

const std = @import("std");
const Allocator = std.mem.Allocator;
const Module = @import("Module.zig");
const fs = std.fs;
const trace = @import("tracy.zig").trace;
const Package = @import("Package.zig");
const Type = @import("type.zig").Type;
const build_options = @import("build_options");
pub const producer_string = if (std.builtin.is_test) "zig test" else "zig " ++ build_options.version;
pub const Options = struct {
target: std.Target,
output_mode: std.builtin.OutputMode,
link_mode: std.builtin.LinkMode,
object_format: std.builtin.ObjectFormat,
optimize_mode: std.builtin.Mode,
root_name: []const u8,
root_pkg: *const Package,
/// Used for calculating how much space to reserve for symbols in case the binary file
/// does not already have a symbol table.
symbol_count_hint: u64 = 32,
/// Used for calculating how much space to reserve for executable program code in case
/// the binary file deos not already have such a section.
program_code_size_hint: u64 = 256 * 1024,
entry_addr: ?u64 = null,
};
pub const File = struct {
tag: Tag,
options: Options,
file: ?fs.File,
allocator: *Allocator,
pub const LinkBlock = union {
elf: Elf.TextBlock,
coff: Coff.TextBlock,
macho: MachO.TextBlock,
c: void,
wasm: void,
};
pub const LinkFn = union {
elf: Elf.SrcFn,
coff: Coff.SrcFn,
macho: MachO.SrcFn,
c: void,
wasm: ?Wasm.FnData,
};
/// For DWARF .debug_info.
pub const DbgInfoTypeRelocsTable = std.HashMapUnmanaged(Type, DbgInfoTypeReloc, Type.hash, Type.eql, std.hash_map.DefaultMaxLoadPercentage);
/// For DWARF .debug_info.
pub const DbgInfoTypeReloc = struct {
/// Offset from `TextBlock.dbg_info_off` (the buffer that is local to a Decl).
/// This is where the .debug_info tag for the type is.
off: u32,
/// Offset from `TextBlock.dbg_info_off` (the buffer that is local to a Decl).
/// List of DW.AT_type / DW.FORM_ref4 that points to the type.
relocs: std.ArrayListUnmanaged(u32),
};
/// Attempts incremental linking, if the file already exists. If
/// incremental linking fails, falls back to truncating the file and
/// rewriting it. A malicious file is detected as incremental link failure
/// and does not cause Illegal Behavior. This operation is not atomic.
pub fn openPath(allocator: *Allocator, dir: fs.Dir, sub_path: []const u8, options: Options) !*File {
switch (options.object_format) {
.unknown => unreachable,
.coff, .pe => return Coff.openPath(allocator, dir, sub_path, options),
.elf => return Elf.openPath(allocator, dir, sub_path, options),
.macho => return MachO.openPath(allocator, dir, sub_path, options),
.wasm => return Wasm.openPath(allocator, dir, sub_path, options),
.c => return C.openPath(allocator, dir, sub_path, options),
.hex => return error.TODOImplementHex,
.raw => return error.TODOImplementRaw,
}
}
pub fn cast(base: *File, comptime T: type) ?*T {
if (base.tag != T.base_tag)
return null;
return @fieldParentPtr(T, "base", base);
}
pub fn makeWritable(base: *File, dir: fs.Dir, sub_path: []const u8) !void {
switch (base.tag) {
.coff, .elf, .macho => {
if (base.file != null) return;
base.file = try dir.createFile(sub_path, .{
.truncate = false,
.read = true,
.mode = determineMode(base.options),
});
},
.c, .wasm => {},
}
}
pub fn makeExecutable(base: *File) !void {
switch (base.tag) {
.c => unreachable,
.wasm => {},
else => if (base.file) |f| {
f.close();
base.file = null;
},
}
}
/// May be called before or after updateDeclExports but must be called
/// after allocateDeclIndexes for any given Decl.
pub fn updateDecl(base: *File, module: *Module, decl: *Module.Decl) !void {
switch (base.tag) {
.coff => return @fieldParentPtr(Coff, "base", base).updateDecl(module, decl),
.elf => return @fieldParentPtr(Elf, "base", base).updateDecl(module, decl),
.macho => return @fieldParentPtr(MachO, "base", base).updateDecl(module, decl),
.c => return @fieldParentPtr(C, "base", base).updateDecl(module, decl),
.wasm => return @fieldParentPtr(Wasm, "base", base).updateDecl(module, decl),
}
}
pub fn updateDeclLineNumber(base: *File, module: *Module, decl: *Module.Decl) !void {
switch (base.tag) {
.coff => return @fieldParentPtr(Coff, "base", base).updateDeclLineNumber(module, decl),
.elf => return @fieldParentPtr(Elf, "base", base).updateDeclLineNumber(module, decl),
.macho => return @fieldParentPtr(MachO, "base", base).updateDeclLineNumber(module, decl),
.c, .wasm => {},
}
}
/// Must be called before any call to updateDecl or updateDeclExports for
/// any given Decl.
pub fn allocateDeclIndexes(base: *File, decl: *Module.Decl) !void {
switch (base.tag) {
.coff => return @fieldParentPtr(Coff, "base", base).allocateDeclIndexes(decl),
.elf => return @fieldParentPtr(Elf, "base", base).allocateDeclIndexes(decl),
.macho => return @fieldParentPtr(MachO, "base", base).allocateDeclIndexes(decl),
.c, .wasm => {},
}
}
pub fn deinit(base: *File) void {
if (base.file) |f| f.close();
switch (base.tag) {
.coff => @fieldParentPtr(Coff, "base", base).deinit(),
.elf => @fieldParentPtr(Elf, "base", base).deinit(),
.macho => @fieldParentPtr(MachO, "base", base).deinit(),
.c => @fieldParentPtr(C, "base", base).deinit(),
.wasm => @fieldParentPtr(Wasm, "base", base).deinit(),
}
}
pub fn destroy(base: *File) void {
switch (base.tag) {
.coff => {
const parent = @fieldParentPtr(Coff, "base", base);
parent.deinit();
base.allocator.destroy(parent);
},
.elf => {
const parent = @fieldParentPtr(Elf, "base", base);
parent.deinit();
base.allocator.destroy(parent);
},
.macho => {
const parent = @fieldParentPtr(MachO, "base", base);
parent.deinit();
base.allocator.destroy(parent);
},
.c => {
const parent = @fieldParentPtr(C, "base", base);
parent.deinit();
base.allocator.destroy(parent);
},
.wasm => {
const parent = @fieldParentPtr(Wasm, "base", base);
parent.deinit();
base.allocator.destroy(parent);
},
}
}
pub fn flush(base: *File, module: *Module) !void {
const tracy = trace(@src());
defer tracy.end();
try switch (base.tag) {
.coff => @fieldParentPtr(Coff, "base", base).flush(module),
.elf => @fieldParentPtr(Elf, "base", base).flush(module),
.macho => @fieldParentPtr(MachO, "base", base).flush(module),
.c => @fieldParentPtr(C, "base", base).flush(module),
.wasm => @fieldParentPtr(Wasm, "base", base).flush(module),
};
}
pub fn freeDecl(base: *File, decl: *Module.Decl) void {
switch (base.tag) {
.coff => @fieldParentPtr(Coff, "base", base).freeDecl(decl),
.elf => @fieldParentPtr(Elf, "base", base).freeDecl(decl),
.macho => @fieldParentPtr(MachO, "base", base).freeDecl(decl),
.c => unreachable,
.wasm => @fieldParentPtr(Wasm, "base", base).freeDecl(decl),
}
}
pub fn errorFlags(base: *File) ErrorFlags {
return switch (base.tag) {
.coff => @fieldParentPtr(Coff, "base", base).error_flags,
.elf => @fieldParentPtr(Elf, "base", base).error_flags,
.macho => @fieldParentPtr(MachO, "base", base).error_flags,
.c => return .{ .no_entry_point_found = false },
.wasm => return ErrorFlags{},
};
}
/// May be called before or after updateDecl, but must be called after
/// allocateDeclIndexes for any given Decl.
pub fn updateDeclExports(
base: *File,
module: *Module,
decl: *const Module.Decl,
exports: []const *Module.Export,
) !void {
switch (base.tag) {
.coff => return @fieldParentPtr(Coff, "base", base).updateDeclExports(module, decl, exports),
.elf => return @fieldParentPtr(Elf, "base", base).updateDeclExports(module, decl, exports),
.macho => return @fieldParentPtr(MachO, "base", base).updateDeclExports(module, decl, exports),
.c => return {},
.wasm => return @fieldParentPtr(Wasm, "base", base).updateDeclExports(module, decl, exports),
}
}
pub fn getDeclVAddr(base: *File, decl: *const Module.Decl) u64 {
switch (base.tag) {
.coff => return @fieldParentPtr(Coff, "base", base).getDeclVAddr(decl),
.elf => return @fieldParentPtr(Elf, "base", base).getDeclVAddr(decl),
.macho => return @fieldParentPtr(MachO, "base", base).getDeclVAddr(decl),
.c => unreachable,
.wasm => unreachable,
}
}
pub const Tag = enum {
coff,
elf,
macho,
c,
wasm,
};
pub const ErrorFlags = struct {
no_entry_point_found: bool = false,
};
pub const C = @import("link/C.zig");
pub const Coff = @import("link/Coff.zig");
pub const Elf = @import("link/Elf.zig");
pub const MachO = @import("link/MachO.zig");
pub const Wasm = @import("link/Wasm.zig");
};
pub fn determineMode(options: Options) fs.File.Mode {
// On common systems with a 0o022 umask, 0o777 will still result in a file created
// with 0o755 permissions, but it works appropriately if the system is configured
// more leniently. As another data point, C's fopen seems to open files with the
// 666 mode.
const executable_mode = if (std.Target.current.os.tag == .windows) 0 else 0o777;
switch (options.output_mode) {
.Lib => return switch (options.link_mode) {
.Dynamic => executable_mode,
.Static => fs.File.default_mode,
},
.Exe => return executable_mode,
.Obj => return fs.File.default_mode,
}
}