link: Improve handling of --build-id when using LLD.

Author: alexrp

src/link/Coff.zig

@@ -1763,6 +1763,7 @@ fn linkWithLLD(coff: *Coff, arena: Allocator, tid: Zcu.PerThread.Id, prog_node:
         man.hash.addOptionalBytes(entry_name);
         man.hash.add(coff.base.stack_size);
         man.hash.add(coff.image_base);
+        man.hash.add(coff.base.build_id);
         {
             // TODO remove this, libraries must instead be resolved by the frontend.
             for (coff.lib_directories) |lib_directory| man.hash.addOptionalBytes(lib_directory.path);
@@ -1895,6 +1896,12 @@ fn linkWithLLD(coff: *Coff, arena: Allocator, tid: Zcu.PerThread.Id, prog_node:
         }
         try argv.append(try allocPrint(arena, "-BASE:{d}", .{coff.image_base}));
 
+        switch (coff.base.build_id) {
+            .none => try argv.append("-BUILD-ID:NO"),
+            .fast => try argv.append("-BUILD-ID"),
+            .uuid, .sha1, .md5, .hexstring => {},
+        }
+
         if (target.cpu.arch == .x86) {
             try argv.append("-MACHINE:X86");
         } else if (target.cpu.arch == .x86_64) {

src/link/Elf.zig

@@ -1596,8 +1596,8 @@ fn linkWithLLD(self: *Elf, arena: Allocator, tid: Zcu.PerThread.Id, prog_node: s
         man.hash.addListOfBytes(self.rpath_table.keys());
         if (output_mode == .Exe) {
             man.hash.add(self.base.stack_size);
-            man.hash.add(self.base.build_id);
         }
+        man.hash.add(self.base.build_id);
         man.hash.addListOfBytes(self.symbol_wrap_set.keys());
         man.hash.add(comp.skip_linker_dependencies);
         man.hash.add(self.z_nodelete);
@@ -1753,20 +1753,14 @@ fn linkWithLLD(self: *Elf, arena: Allocator, tid: Zcu.PerThread.Id, prog_node: s
             });
         }
 
-        if (is_exe_or_dyn_lib) {
-            switch (self.base.build_id) {
-                .none => {},
-                .fast, .uuid, .sha1, .md5 => {
-                    try argv.append(try std.fmt.allocPrint(arena, "--build-id={s}", .{
-                        @tagName(self.base.build_id),
-                    }));
-                },
-                .hexstring => |hs| {
-                    try argv.append(try std.fmt.allocPrint(arena, "--build-id=0x{s}", .{
-                        std.fmt.fmtSliceHexLower(hs.toSlice()),
-                    }));
-                },
-            }
+        switch (self.base.build_id) {
+            .none => try argv.append("--build-id=none"),
+            .fast, .uuid, .sha1, .md5 => try argv.append(try std.fmt.allocPrint(arena, "--build-id={s}", .{
+                @tagName(self.base.build_id),
+            })),
+            .hexstring => |hs| try argv.append(try std.fmt.allocPrint(arena, "--build-id=0x{s}", .{
+                std.fmt.fmtSliceHexLower(hs.toSlice()),
+            })),
         }
 
         try argv.append(try std.fmt.allocPrint(arena, "--image-base={d}", .{self.image_base}));

src/link/Wasm.zig

@@ -4078,6 +4078,17 @@ fn linkWithLLD(wasm: *Wasm, arena: Allocator, tid: Zcu.PerThread.Id, prog_node:
             try std.fmt.allocPrint(arena, "stack-size={d}", .{wasm.base.stack_size}),
         });
 
+        switch (wasm.base.build_id) {
+            .none => try argv.append("--build-id=none"),
+            .fast, .uuid, .sha1 => try argv.append(try std.fmt.allocPrint(arena, "--build-id={s}", .{
+                @tagName(wasm.base.build_id),
+            })),
+            .hexstring => |hs| try argv.append(try std.fmt.allocPrint(arena, "--build-id=0x{s}", .{
+                std.fmt.fmtSliceHexLower(hs.toSlice()),
+            })),
+            .md5 => {},
+        }
+
         if (wasm.import_symbols) {
             try argv.append("--allow-undefined");
         }
@@ -4089,11 +4100,6 @@ fn linkWithLLD(wasm: *Wasm, arena: Allocator, tid: Zcu.PerThread.Id, prog_node:
             try argv.append("--pie");
         }
 
-        // XXX - TODO: add when wasm-ld supports --build-id.
-        // if (wasm.base.build_id) {
-        //     try argv.append("--build-id=tree");
-        // }
-
         try argv.appendSlice(&.{ "-o", full_out_path });
 
         if (target.cpu.arch == .wasm64) {