zig/src/link/Elf/file.zig
2025-07-07 22:43:52 -07:00

301 lines
11 KiB
Zig

pub const File = union(enum) {
zig_object: *ZigObject,
linker_defined: *LinkerDefined,
object: *Object,
shared_object: *SharedObject,
pub fn index(file: File) Index {
return switch (file) {
inline else => |x| x.index,
};
}
pub fn fmtPath(file: File) std.fmt.Formatter(File, formatPath) {
return .{ .data = file };
}
fn formatPath(file: File, writer: *std.io.Writer) std.io.Writer.Error!void {
switch (file) {
.zig_object => |zo| try writer.writeAll(zo.basename),
.linker_defined => try writer.writeAll("(linker defined)"),
.object => |x| try writer.print("{f}", .{x.fmtPath()}),
.shared_object => |x| try writer.print("{f}", .{@as(Path, x.path)}),
}
}
pub fn isAlive(file: File) bool {
return switch (file) {
.zig_object => true,
.linker_defined => true,
inline else => |x| x.alive,
};
}
/// Encodes symbol rank so that the following ordering applies:
/// * strong defined
/// * weak defined
/// * strong in lib (dso/archive)
/// * weak in lib (dso/archive)
/// * common
/// * common in lib (archive)
/// * unclaimed
pub fn symbolRank(file: File, sym: elf.Elf64_Sym, in_archive: bool) u32 {
const base: u3 = blk: {
if (sym.st_shndx == elf.SHN_COMMON) break :blk if (in_archive) 6 else 5;
if (file == .shared_object or in_archive) break :blk switch (sym.st_bind()) {
elf.STB_GLOBAL => 3,
else => 4,
};
break :blk switch (sym.st_bind()) {
elf.STB_GLOBAL => 1,
else => 2,
};
};
return (@as(u32, base) << 24) + file.index();
}
pub fn resolveSymbols(file: File, elf_file: *Elf) !void {
return switch (file) {
inline else => |x| x.resolveSymbols(elf_file),
};
}
pub fn setAlive(file: File) void {
switch (file) {
.zig_object, .linker_defined => {},
inline else => |x| x.alive = true,
}
}
pub fn markLive(file: File, elf_file: *Elf) void {
switch (file) {
.linker_defined => {},
inline else => |x| x.markLive(elf_file),
}
}
pub fn scanRelocs(file: File, elf_file: *Elf, undefs: anytype) !void {
switch (file) {
.linker_defined, .shared_object => unreachable,
inline else => |x| try x.scanRelocs(elf_file, undefs),
}
}
pub fn createSymbolIndirection(file: File, elf_file: *Elf) !void {
const impl = struct {
fn impl(sym: *Symbol, ref: Elf.Ref, ef: *Elf) !void {
if (!sym.isLocal(ef) and !sym.flags.has_dynamic) {
log.debug("'{s}' is non-local", .{sym.name(ef)});
try ef.dynsym.addSymbol(ref, ef);
}
if (sym.flags.needs_got and !sym.flags.has_got) {
log.debug("'{s}' needs GOT", .{sym.name(ef)});
_ = try ef.got.addGotSymbol(ref, ef);
}
if (sym.flags.needs_plt) {
if (sym.flags.is_canonical and !sym.flags.has_plt) {
log.debug("'{s}' needs CPLT", .{sym.name(ef)});
sym.flags.@"export" = true;
try ef.plt.addSymbol(ref, ef);
} else if (sym.flags.needs_got and !sym.flags.has_pltgot) {
log.debug("'{s}' needs PLTGOT", .{sym.name(ef)});
try ef.plt_got.addSymbol(ref, ef);
} else if (!sym.flags.has_plt) {
log.debug("'{s}' needs PLT", .{sym.name(ef)});
try ef.plt.addSymbol(ref, ef);
}
}
if (sym.flags.needs_copy_rel and !sym.flags.has_copy_rel) {
log.debug("'{s}' needs COPYREL", .{sym.name(ef)});
try ef.copy_rel.addSymbol(ref, ef);
}
if (sym.flags.needs_tlsgd and !sym.flags.has_tlsgd) {
log.debug("'{s}' needs TLSGD", .{sym.name(ef)});
try ef.got.addTlsGdSymbol(ref, ef);
}
if (sym.flags.needs_gottp and !sym.flags.has_gottp) {
log.debug("'{s}' needs GOTTP", .{sym.name(ef)});
try ef.got.addGotTpSymbol(ref, ef);
}
if (sym.flags.needs_tlsdesc and !sym.flags.has_tlsdesc) {
log.debug("'{s}' needs TLSDESC", .{sym.name(ef)});
try ef.got.addTlsDescSymbol(ref, ef);
}
}
}.impl;
switch (file) {
.zig_object => |x| {
for (x.local_symbols.items, 0..) |idx, i| {
const sym = &x.symbols.items[idx];
const ref = x.resolveSymbol(@intCast(i), elf_file);
const ref_sym = elf_file.symbol(ref) orelse continue;
if (ref_sym.file(elf_file).?.index() != x.index) continue;
try impl(sym, ref, elf_file);
}
for (x.global_symbols.items, 0..) |idx, i| {
const sym = &x.symbols.items[idx];
const ref = x.resolveSymbol(@intCast(i | ZigObject.global_symbol_bit), elf_file);
const ref_sym = elf_file.symbol(ref) orelse continue;
if (ref_sym.file(elf_file).?.index() != x.index) continue;
try impl(sym, ref, elf_file);
}
},
inline else => |x| {
for (x.symbols.items, 0..) |*sym, i| {
const ref = x.resolveSymbol(@intCast(i), elf_file);
const ref_sym = elf_file.symbol(ref) orelse continue;
if (ref_sym.file(elf_file).?.index() != x.index) continue;
try impl(sym, ref, elf_file);
}
},
}
}
pub fn atom(file: File, atom_index: Atom.Index) ?*Atom {
return switch (file) {
.shared_object => unreachable,
.linker_defined => null,
inline else => |x| x.atom(atom_index),
};
}
pub fn atoms(file: File) []const Atom.Index {
return switch (file) {
.shared_object => unreachable,
.linker_defined => &[0]Atom.Index{},
.zig_object => |x| x.atoms_indexes.items,
.object => |x| x.atoms_indexes.items,
};
}
pub fn atomExtra(file: File, extra_index: u32) Atom.Extra {
return switch (file) {
.shared_object, .linker_defined => unreachable,
inline else => |x| x.atomExtra(extra_index),
};
}
pub fn setAtomExtra(file: File, extra_index: u32, extra: Atom.Extra) void {
return switch (file) {
.shared_object, .linker_defined => unreachable,
inline else => |x| x.setAtomExtra(extra_index, extra),
};
}
pub fn cies(file: File) []const Cie {
return switch (file) {
.zig_object => &[0]Cie{},
.object => |x| x.cies.items,
inline else => unreachable,
};
}
pub fn group(file: File, ind: Elf.Group.Index) *Elf.Group {
return switch (file) {
.linker_defined, .shared_object, .zig_object => unreachable,
.object => |x| x.group(ind),
};
}
pub fn resolveSymbol(file: File, ind: Symbol.Index, elf_file: *Elf) Elf.Ref {
return switch (file) {
inline else => |x| x.resolveSymbol(ind, elf_file),
};
}
pub fn symbol(file: File, ind: Symbol.Index) *Symbol {
return switch (file) {
.zig_object => |x| x.symbol(ind),
inline else => |x| &x.symbols.items[ind],
};
}
pub fn getString(file: File, off: u32) [:0]const u8 {
return switch (file) {
inline else => |x| x.getString(off),
};
}
pub fn updateSymtabSize(file: File, elf_file: *Elf) !void {
return switch (file) {
inline else => |x| x.updateSymtabSize(elf_file),
};
}
pub fn writeSymtab(file: File, elf_file: *Elf) void {
return switch (file) {
inline else => |x| x.writeSymtab(elf_file),
};
}
pub fn updateArSymtab(file: File, ar_symtab: *Archive.ArSymtab, elf_file: *Elf) !void {
return switch (file) {
.zig_object => |x| x.updateArSymtab(ar_symtab, elf_file),
.object => |x| x.updateArSymtab(ar_symtab, elf_file),
else => unreachable,
};
}
pub fn updateArStrtab(file: File, allocator: Allocator, ar_strtab: *Archive.ArStrtab) !void {
switch (file) {
.zig_object => |zo| {
const basename = zo.basename;
if (basename.len <= Archive.max_member_name_len) return;
zo.output_ar_state.name_off = try ar_strtab.insert(allocator, basename);
},
.object => |o| {
const basename = std.fs.path.basename(o.path.sub_path);
if (basename.len <= Archive.max_member_name_len) return;
o.output_ar_state.name_off = try ar_strtab.insert(allocator, basename);
},
else => unreachable,
}
}
pub fn updateArSize(file: File, elf_file: *Elf) !void {
return switch (file) {
.zig_object => |x| x.updateArSize(),
.object => |x| x.updateArSize(elf_file),
else => unreachable,
};
}
pub fn writeAr(file: File, elf_file: *Elf, writer: anytype) !void {
return switch (file) {
.zig_object => |x| x.writeAr(writer),
.object => |x| x.writeAr(elf_file, writer),
else => unreachable,
};
}
pub const Index = u32;
pub const Entry = union(enum) {
null,
zig_object,
linker_defined: LinkerDefined,
object: Object,
shared_object: SharedObject,
};
pub const Handle = std.fs.File;
pub const HandleIndex = Index;
};
const std = @import("std");
const elf = std.elf;
const log = std.log.scoped(.link);
const Path = std.Build.Cache.Path;
const Allocator = std.mem.Allocator;
const Archive = @import("Archive.zig");
const Atom = @import("Atom.zig");
const Cie = @import("eh_frame.zig").Cie;
const Elf = @import("../Elf.zig");
const LinkerDefined = @import("LinkerDefined.zig");
const Object = @import("Object.zig");
const SharedObject = @import("SharedObject.zig");
const Symbol = @import("Symbol.zig");
const ZigObject = @import("ZigObject.zig");