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Merge pull request #17141 from ziglang/elf-linker

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elf: enable Zig's ELF linker on non-incremental codepaths (LLVM, clang)
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Jakub Konka 2023-09-13 21:49:10 +02:00 committed by GitHub
commit 10a99f8f64
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1 changed files with 53 additions and 15 deletions
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68
src/link/Elf.zig
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@ -164,13 +164,21 @@ pub const PtrWidth = enum { p32, p64 };
pub fn openPath(allocator: Allocator, sub_path: []const u8, options: link.Options) !*Elf {
assert(options.target.ofmt == .elf);
if (options.use_llvm) {
return createEmpty(allocator, options);
}
const self = try createEmpty(allocator, options);
errdefer self.base.destroy();
if (options.use_llvm) {
const use_lld = build_options.have_llvm and self.base.options.use_lld;
if (use_lld) return self;
if (options.module != null) {
self.base.intermediary_basename = try std.fmt.allocPrint(allocator, "{s}{s}", .{
sub_path, options.target.ofmt.fileExt(options.target.cpu.arch),
});
}
}
errdefer if (self.base.intermediary_basename) |path| allocator.free(path);
self.base.file = try options.emit.?.directory.handle.createFile(sub_path, .{
.truncate = false,
.read = true,
@ -389,8 +397,6 @@ pub fn findFreeSpace(self: *Elf, object_size: u64, min_alignment: u32) u64 {
}
pub fn populateMissingMetadata(self: *Elf) !void {
assert(self.llvm_object == null);
const gpa = self.base.allocator;
const small_ptr = switch (self.ptr_width) {
.p32 => true,
@ -962,7 +968,7 @@ pub fn markDirty(self: *Elf, shdr_index: u16, phdr_index: ?u16) void {
pub fn flush(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node) link.File.FlushError!void {
if (self.base.options.emit == null) {
if (self.llvm_object) |llvm_object| {
return try llvm_object.flushModule(comp, prog_node);
try llvm_object.flushModule(comp, prog_node);
}
return;
}
@ -981,7 +987,10 @@ pub fn flushModule(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node
defer tracy.end();
if (self.llvm_object) |llvm_object| {
return try llvm_object.flushModule(comp, prog_node);
try llvm_object.flushModule(comp, prog_node);
const use_lld = build_options.have_llvm and self.base.options.use_lld;
if (use_lld) return;
}
const gpa = self.base.allocator;
@ -989,9 +998,12 @@ pub fn flushModule(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node
sub_prog_node.activate();
defer sub_prog_node.end();
// TODO This linker code currently assumes there is only 1 compilation unit and it
// corresponds to the Zig source code.
const module = self.base.options.module orelse return error.LinkingWithoutZigSourceUnimplemented;
var arena_allocator = std.heap.ArenaAllocator.init(self.base.allocator);
defer arena_allocator.deinit();
const arena = arena_allocator.allocator();
const directory = self.base.options.emit.?.directory; // Just an alias to make it shorter to type.
const full_out_path = try directory.join(arena, &[_][]const u8{self.base.options.emit.?.sub_path});
const compiler_rt_path: ?[]const u8 = blk: {
if (comp.compiler_rt_lib) |x| break :blk x.full_object_path;
@ -1002,8 +1014,19 @@ pub fn flushModule(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node
// Here we will parse input positional and library files (if referenced).
// This will roughly match in any linker backend we support.
var positionals = std.ArrayList(Compilation.LinkObject).init(gpa);
defer positionals.deinit();
var positionals = std.ArrayList(Compilation.LinkObject).init(arena);
if (self.base.intermediary_basename) |path| {
const full_path = blk: {
if (fs.path.dirname(full_out_path)) |dirname| {
break :blk try fs.path.join(arena, &.{ dirname, path });
} else {
break :blk path;
}
};
try positionals.append(.{ .path = full_path });
}
try positionals.ensureUnusedCapacity(self.base.options.objects.len);
positionals.appendSliceAssumeCapacity(self.base.options.objects);
@ -1025,6 +1048,8 @@ pub fn flushModule(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node
// Handle any lazy symbols that were emitted by incremental compilation.
if (self.lazy_syms.getPtr(.none)) |metadata| {
const module = self.base.options.module.?;
// Most lazy symbols can be updated on first use, but
// anyerror needs to wait for everything to be flushed.
if (metadata.text_state != .unused) self.updateLazySymbol(
@ -1051,7 +1076,7 @@ pub fn flushModule(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node
const foreign_endian = target_endian != builtin.cpu.arch.endian();
if (self.dwarf) |*dw| {
try dw.flushModule(module);
try dw.flushModule(self.base.options.module.?);
}
// If we haven't already, create a linker-generated input file comprising of
@ -1099,6 +1124,19 @@ pub fn flushModule(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node
}
try self.writeObjects();
// Look for entry address in objects if not set by the incremental compiler.
if (self.entry_addr == null) {
const entry: ?[]const u8 = entry: {
if (self.base.options.entry) |entry| break :entry entry;
if (!self.isDynLib()) break :entry "_start";
break :entry null;
};
self.entry_addr = if (entry) |name| entry_addr: {
const global_index = self.globalByName(name) orelse break :entry_addr null;
break :entry_addr self.symbol(global_index).value;
} else null;
}
// Generate and emit the symbol table.
try self.updateSymtabSize();
try self.writeSymtab();
@ -1125,7 +1163,7 @@ pub fn flushModule(self: *Elf, comp: *Compilation, prog_node: *std.Progress.Node
const text_phdr = &self.phdrs.items[self.phdr_load_re_index.?];
const low_pc = text_phdr.p_vaddr;
const high_pc = text_phdr.p_vaddr + text_phdr.p_memsz;
try dw.writeDbgInfoHeader(module, low_pc, high_pc);
try dw.writeDbgInfoHeader(self.base.options.module.?, low_pc, high_pc);
self.debug_info_header_dirty = false;
}