diff --git a/lib/std/build.zig b/lib/std/build.zig index fcaa115ccb..6ac592cb7e 100644 --- a/lib/std/build.zig +++ b/lib/std/build.zig @@ -17,6 +17,7 @@ const fmt_lib = std.fmt; const File = std.fs.File; const CrossTarget = std.zig.CrossTarget; const NativeTargetInfo = std.zig.system.NativeTargetInfo; +const Sha256 = std.crypto.hash.sha2.Sha256; pub const FmtStep = @import("build/FmtStep.zig"); pub const TranslateCStep = @import("build/TranslateCStep.zig"); @@ -2888,6 +2889,48 @@ pub const LibExeObjStep = struct { try zig_args.append("--enable-cache"); + const is_build = switch (self.kind) { + .lib => true, + .exe => true, + .obj => true, + else => false, + }; + if (is_build) { + // Windows has an argument length limit of 32,766 characters, macOS 262,144 and Linux + // 2,097,152. If our args exceed 30 KiB, we instead write them to a "response file" and + // pass that to zig, e.g. via 'zig build-lib @args.rsp' + var args_length: usize = 0; + for (zig_args.items) |arg| { + args_length += arg.len; + } + if (args_length >= 30 * 1024) { + const args_dir = try fs.path.join( + builder.allocator, + &[_][]const u8{ builder.pathFromRoot("zig-cache"), "args" }, + ); + try std.fs.cwd().makePath(args_dir); + + // Write the args to zig-cache/args/ to avoid conflicts with + // other zig build commands running in parallel. + const partially_quoted = try std.mem.join(builder.allocator, "\" \"", zig_args.items[2..]); + const args = try std.mem.concat(builder.allocator, u8, &[_][]const u8{ "\"", partially_quoted, "\"" }); + + var args_hash: [Sha256.digest_length]u8 = undefined; + Sha256.hash(args, &args_hash, .{}); + var args_hex_hash: [Sha256.digest_length * 2]u8 = undefined; + _ = try std.fmt.bufPrint( + &args_hex_hash, + "{s}", + .{std.fmt.fmtSliceHexLower(&args_hash)}, + ); + + const args_file = try fs.path.join(builder.allocator, &[_][]const u8{ args_dir, args_hex_hash[0..] }); + try std.fs.cwd().writeFile(args_file, args); + + zig_args.shrinkRetainingCapacity(2); + try zig_args.append(try std.mem.concat(builder.allocator, u8, &[_][]const u8{ "@", args_file })); + } + } const output_dir_nl = try builder.execFromStep(zig_args.items, &self.step); const build_output_dir = mem.trimRight(u8, output_dir_nl, "\r\n");