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elf: report undefined symbols in objects

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This commit is contained in:
Jakub Konka 2023-09-12 00:10:54 +02:00
parent 67d458370d
commit 00787885f4
4 changed files with 87 additions and 51 deletions
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114
src/link/Elf.zig
View File

@ -843,6 +843,7 @@ pub fn populateMissingMetadata(self: *Elf) !void {
sym.name_offset = name_off;
esym.st_name = name_off;
esym.st_info |= elf.STT_FILE;
esym.st_shndx = elf.SHN_ABS;
}
}
}
@ -1299,22 +1300,19 @@ fn parseObject(self: *Elf, in_file: std.fs.File, path: []const u8, ctx: *ParseEr
const gpa = self.base.allocator;
const data = try in_file.readToEndAlloc(gpa, std.math.maxInt(u32));
const index = @as(File.Index, @intCast(self.files.slice().len));
var object = Object{
const index = @as(File.Index, @intCast(try self.files.addOne(gpa)));
self.files.set(index, .{ .object = .{
.path = path,
.data = data,
.index = index,
};
errdefer object.deinit(gpa);
} });
try self.objects.append(gpa, index);
const object = self.file(index).?.object;
try object.parse(self);
ctx.detected_cpu_arch = object.header.?.e_machine.toTargetCpuArch().?;
if (ctx.detected_cpu_arch != self.base.options.target.cpu.arch) return error.InvalidCpuArch;
_ = try self.files.addOne(gpa);
self.files.set(index, .{ .object = object });
try self.objects.append(gpa, index);
}
fn linkWithLLD(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node) !void {
@ -2690,12 +2688,14 @@ pub fn updateDeclExports(
break :blk sym_index;
};
const sym = self.symbol(sym_index);
sym.flags.@"export" = true;
sym.value = decl_sym.value;
sym.atom_index = decl_sym.atom_index;
sym.output_section_index = decl_sym.output_section_index;
const esym = zig_module.sourceSymbol(sym_index, self);
esym.* = decl_esym;
esym.st_info = (stb_bits << 4) | stt_bits;
_ = self.unresolved.swapRemove(sym_index);
}
}
@ -3468,13 +3468,8 @@ pub fn globalByName(self: *Elf, name: []const u8) ?Symbol.Index {
pub fn getGlobalSymbol(self: *Elf, name: []const u8, lib_name: ?[]const u8) !u32 {
_ = lib_name;
const gpa = self.base.allocator;
const name_off = try self.strtab.insert(gpa, name);
const gop = try self.getOrPutGlobal(name_off);
if (!gop.found_existing) {
try self.unresolved.putNoClobber(gpa, gop.index, {});
}
return gop.index;
const zig_module = self.file(self.zig_module_index.?).?.zig_module;
return zig_module.addGlobal(name, self);
}
const GetOrCreateComdatGroupOwnerResult = struct {
@ -3519,42 +3514,83 @@ fn reportUndefined(self: *Elf) !void {
try self.misc_errors.ensureUnusedCapacity(gpa, self.unresolved.keys().len);
for (self.unresolved.keys()) |sym_index| {
const undef_sym = self.symbol(sym_index);
const CollectStruct = struct {
notes: [max_notes]link.File.ErrorMsg = [_]link.File.ErrorMsg{.{ .msg = undefined }} ** max_notes,
notes_len: u3 = 0,
notes_count: usize = 0,
};
var all_notes: usize = 0;
var notes = try std.ArrayList(link.File.ErrorMsg).initCapacity(gpa, max_notes + 1);
defer notes.deinit();
const collect: []CollectStruct = try gpa.alloc(CollectStruct, self.unresolved.keys().len);
defer gpa.free(collect);
@memset(collect, .{});
// Collect all references across all input files
if (self.zig_module_index) |index| {
const zig_module = self.file(index).?.zig_module;
for (zig_module.atoms.keys()) |atom_index| {
const atom_ptr = self.atom(atom_index).?;
if (!atom_ptr.alive) continue;
// Collect all references across all input files
if (self.zig_module_index) |index| {
const zig_module = self.file(index).?.zig_module;
for (zig_module.atoms.keys()) |atom_index| {
const atom_ptr = self.atom(atom_index).?;
if (!atom_ptr.alive) continue;
for (atom_ptr.relocs(self)) |rel| {
if (sym_index == rel.r_sym()) {
const note = try std.fmt.allocPrint(gpa, "referenced by {s}:{s}", .{
zig_module.path,
atom_ptr.name(self),
});
notes.appendAssumeCapacity(.{ .msg = note });
all_notes += 1;
break;
for (atom_ptr.relocs(self)) |rel| {
if (self.unresolved.getIndex(rel.r_sym())) |bin_index| {
const note = try std.fmt.allocPrint(gpa, "referenced by {s}:{s}", .{
zig_module.path,
atom_ptr.name(self),
});
const bin = &collect[bin_index];
if (bin.notes_len < max_notes) {
bin.notes[bin.notes_len] = .{ .msg = note };
bin.notes_len += 1;
}
bin.notes_count += 1;
}
}
}
}
if (all_notes > max_notes) {
const remaining = all_notes - max_notes;
for (self.objects.items) |index| {
const object = self.file(index).?.object;
for (object.atoms.items) |atom_index| {
const atom_ptr = self.atom(atom_index) orelse continue;
if (!atom_ptr.alive) continue;
for (atom_ptr.relocs(self)) |rel| {
const sym_index = object.symbols.items[rel.r_sym()];
if (self.unresolved.getIndex(sym_index)) |bin_index| {
const note = try std.fmt.allocPrint(gpa, "referenced by {}:{s}", .{
object.fmtPath(),
atom_ptr.name(self),
});
const bin = &collect[bin_index];
if (bin.notes_len < max_notes) {
bin.notes[bin.notes_len] = .{ .msg = note };
bin.notes_len += 1;
}
bin.notes_count += 1;
}
}
}
}
// Generate error notes
for (self.unresolved.keys(), 0..) |sym_index, bin_index| {
const collected = &collect[bin_index];
var notes = try std.ArrayList(link.File.ErrorMsg).initCapacity(gpa, max_notes + 1);
defer notes.deinit();
for (collected.notes[0..collected.notes_len]) |note| {
notes.appendAssumeCapacity(note);
}
if (collected.notes_count > max_notes) {
const remaining = collected.notes_count - max_notes;
const note = try std.fmt.allocPrint(gpa, "referenced {d} more times", .{remaining});
notes.appendAssumeCapacity(.{ .msg = note });
}
var err_msg = link.File.ErrorMsg{
.msg = try std.fmt.allocPrint(gpa, "undefined symbol: {s}", .{undef_sym.name(self)}),
.msg = try std.fmt.allocPrint(gpa, "undefined symbol: {s}", .{self.symbol(sym_index).name(self)}),
};
err_msg.notes = try notes.toOwnedSlice();

9
src/link/Elf/LinkerDefined.zig
View File

@ -46,15 +46,6 @@ pub fn resolveSymbols(self: *LinkerDefined, elf_file: *Elf) void {
}
}
// pub fn resetGlobals(self: *LinkerDefined, elf_file: *Elf) void {
// for (self.symbols.items) |index| {
// const global = elf_file.getSymbol(index);
// const name = global.name;
// global.* = .{};
// global.name = name;
// }
// }
pub fn updateSymtabSize(self: *LinkerDefined, elf_file: *Elf) void {
for (self.globals()) |global_index| {
const global = elf_file.symbol(global_index);

9
src/link/Elf/Object.zig
View File

@ -187,6 +187,7 @@ fn addAtom(self: *Object, shdr: elf.Elf64_Shdr, shndx: u16, name: [:0]const u8,
atom.name_offset = try elf_file.strtab.insert(elf_file.base.allocator, name);
atom.file_index = self.index;
atom.input_section_index = shndx;
atom.alive = true;
self.atoms.items[shndx] = atom_index;
if (shdr.sh_flags & elf.SHF_COMPRESSED != 0) {
@ -244,6 +245,10 @@ fn initSymtab(self: *Object, elf_file: *Elf) !void {
const off = try elf_file.strtab.insert(gpa, name);
const gop = try elf_file.getOrPutGlobal(off);
self.symbols.addOneAssumeCapacity().* = gop.index;
if (sym.st_shndx == elf.SHN_UNDEF) {
try elf_file.unresolved.put(gpa, gop.index, {});
}
}
}
@ -394,6 +399,8 @@ pub fn resolveSymbols(self: *Object, elf_file: *Elf) void {
if (!atom.alive) continue;
}
_ = elf_file.unresolved.swapRemove(index);
const global = elf_file.symbol(index);
if (self.asFile().symbolRank(this_sym, !self.alive) < global.symbolRank(elf_file)) {
const atom = switch (this_sym.st_shndx) {
@ -598,7 +605,7 @@ pub fn globals(self: *Object) []const u32 {
return self.symbols.items[start..];
}
pub inline fn shdrContents(self: *Object, index: u32) []const u8 {
pub fn shdrContents(self: *Object, index: u32) []const u8 {
assert(index < self.shdrs.items.len);
const shdr = self.shdrs.items[index];
return self.data[shdr.sh_offset..][0..shdr.sh_size];

6
src/link/Elf/ZigModule.zig
View File

@ -58,7 +58,7 @@ pub fn addLocal(self: *ZigModule, elf_file: *Elf) !Symbol.Index {
return symbol_index;
}
pub fn addGlobal(self: *ZigModule, name: [:0]const u8, elf_file: *Elf) !Symbol.Index {
pub fn addGlobal(self: *ZigModule, name: []const u8, elf_file: *Elf) !Symbol.Index {
const gpa = elf_file.base.allocator;
try self.elf_global_symbols.ensureUnusedCapacity(gpa, 1);
try self.global_symbols.ensureUnusedCapacity(gpa, 1);
@ -69,10 +69,12 @@ pub fn addGlobal(self: *ZigModule, name: [:0]const u8, elf_file: *Elf) !Symbol.I
esym.st_name = off;
esym.st_info = elf.STB_GLOBAL << 4;
const gop = try elf_file.getOrPutGlobal(off);
if (!gop.found_existing) {
try elf_file.unresolved.putNoClobber(gpa, gop.index, {});
}
const sym = elf_file.symbol(gop.index);
sym.file_index = self.index;
sym.esym_index = esym_index;
sym.flags.@"export" = true;
self.global_symbols.putAssumeCapacityNoClobber(gop.index, {});
return gop.index;
}