Merge pull request #167 from haberman/bazel25

Fixes to make upb and upb_proto_library() work with Blaze inside Google

13 files changed, 483 insertions, 428 deletions

diff --git a/BUILD b/BUILD
index 6ad365e..362417a 100644
--- a/BUILD
+++ b/BUILD
@@ -7,11 +7,13 @@ load(
     "lua_library",
     "lua_test",
     "make_shell_script",
-    "map_dep",
     "upb_amalgamation",
+)
+
+load(
+    ":upb_proto_library.bzl",
     "upb_proto_library",
     "upb_proto_reflection_library",
-    "upb_proto_srcs",
 )
 
 licenses(["notice"])  # BSD (Google-authored w/ possible external contributions)
@@ -49,8 +51,6 @@ cc_library(
         "upb/decode.c",
         "upb/encode.c",
         "upb/msg.c",
-        "upb/port_def.inc",
-        "upb/port_undef.inc",
         "upb/table.c",
         "upb/table.int.h",
         "upb/upb.c",
@@ -63,12 +63,18 @@ cc_library(
         "upb/upb.h",
     ],
     copts = COPTS,
+    # Internal-only, but we have to make them public for generated code.
+    textual_hdrs = [
+        "upb/port_def.inc",
+        "upb/port_undef.inc",
+    ],
     visibility = ["//visibility:public"],
 )
 
 upb_proto_library(
     name = "descriptor_upbproto",
     deps = ["@com_google_protobuf//:descriptor_proto"],
+    visibility = ["//visibility:public"],
 )
 
 cc_library(
@@ -85,7 +91,8 @@ cc_library(
     visibility = ["//visibility:public"],
     deps = [
         ":descriptor_upbproto",
-        ":upb"
+        ":table",
+        ":upb",
     ],
 )
 
@@ -105,8 +112,11 @@ cc_library(
         "upb/legacy_msg_reflection.c",
     ],
     hdrs = ["upb/legacy_msg_reflection.h"],
-    deps = [":upb"],
     copts = COPTS,
+    deps = [
+        ":table",
+        ":upb",
+    ],
 )
 
 cc_library(
@@ -123,6 +133,7 @@ cc_library(
     copts = COPTS,
     deps = [
         ":reflection",
+        ":table",
         ":upb",
     ],
 )
@@ -145,12 +156,15 @@ cc_library(
     ],
     copts = COPTS,
     deps = [
+        ":descriptor_upbproto",
         ":handlers",
+        ":reflection",
         ":table",
         ":upb",
     ],
 )
 
+# copybara:strip_for_google3_begin
 cc_library(
     name = "upb_json",
     srcs = [
@@ -167,13 +181,18 @@ cc_library(
         ":upb_pb",
     ],
 )
+# copybara:strip_end
 
 cc_library(
     name = "upb_cc_bindings",
     hdrs = [
         "upb/bindings/stdc++/string.h",
     ],
-    deps = [":upb"],
+    deps = [
+        ":descriptor_upbproto",
+        ":handlers",
+        ":upb",
+    ],
 )
 
 # upb compiler #################################################################
@@ -186,31 +205,30 @@ cc_library(
         "upbc/message_layout.h",
     ],
     hdrs = ["upbc/generator.h"],
+    copts = CPPOPTS,
     deps = [
-        map_dep("@absl//absl/base:core_headers"),
-        map_dep("@absl//absl/strings"),
-        map_dep("@com_google_protobuf//:protobuf"),
-        map_dep("@com_google_protobuf//:protoc_lib"),
+        "@absl//absl/base:core_headers",
+        "@absl//absl/container:flat_hash_map",
+        "@absl//absl/strings",
+        "@com_google_protobuf//:protobuf",
+        "@com_google_protobuf//:protoc_lib",
     ],
-    copts = CPPOPTS,
 )
 
 cc_binary(
     name = "protoc-gen-upb",
     srcs = ["upbc/main.cc"],
+    copts = CPPOPTS,
+    visibility = ["//visibility:public"],
     deps = [
         ":upbc_generator",
-        map_dep("@com_google_protobuf//:protoc_lib"),
+        "@com_google_protobuf//:protoc_lib",
     ],
-    copts = CPPOPTS,
-    visibility = ["//visibility:public"],
 )
 
 # We strip the tests and remaining rules from google3 until the upb_proto_library()
 # and upb_proto_reflection_library() rules are fixed.
 
-# copybara:strip_for_google3_begin
-
 # C/C++ tests ##################################################################
 
 cc_library(
@@ -224,16 +242,24 @@ cc_library(
         "tests/upb_test.h",
     ],
     copts = CPPOPTS,
+    deps = [
+        ":handlers",
+        ":upb",
+    ],
 )
 
 cc_test(
     name = "test_varint",
-    srcs = ["tests/pb/test_varint.c"],
+    srcs = [
+        "tests/pb/test_varint.c",
+        "upb/pb/varint.int.h",
+    ],
+    copts = COPTS,
     deps = [
+        ":upb",
         ":upb_pb",
         ":upb_test",
     ],
-    copts = COPTS,
 )
 
 proto_library(
@@ -245,35 +271,23 @@ proto_library(
 
 upb_proto_reflection_library(
     name = "test_decoder_upbproto",
-    deps = ["test_decoder_proto"],
+    deps = [":test_decoder_proto"],
 )
 
 cc_test(
     name = "test_decoder",
-    srcs = ["tests/pb/test_decoder.cc"],
-    deps = [
-        ":test_decoder_upbproto",
-        ":upb_pb",
-        ":upb_test",
+    srcs = [
+        "tests/pb/test_decoder.cc",
+        "upb/pb/varint.int.h",
     ],
     copts = CPPOPTS,
-)
-
-upb_proto_reflection_library(
-    name = "descriptor_upbreflection",
-    deps = ["@com_google_protobuf//:descriptor_proto"],
-)
-
-cc_test(
-    name = "test_encoder",
-    srcs = ["tests/pb/test_encoder.cc"],
     deps = [
-        "descriptor_upbreflection",
-        ":upb_cc_bindings",
+        ":handlers",
+        ":test_decoder_upbproto",
+        ":upb",
         ":upb_pb",
         ":upb_test",
     ],
-    copts = CPPOPTS,
 )
 
 proto_library(
@@ -291,23 +305,46 @@ upb_proto_reflection_library(
 cc_test(
     name = "test_cpp",
     srcs = ["tests/test_cpp.cc"],
+    copts = CPPOPTS,
     deps = [
+        ":handlers",
+        ":reflection",
         ":test_cpp_upbproto",
         ":upb",
         ":upb_pb",
         ":upb_test",
     ],
-    copts = CPPOPTS,
 )
 
 cc_test(
     name = "test_table",
     srcs = ["tests/test_table.cc"],
+    copts = CPPOPTS,
     deps = [
+        ":table",
         ":upb",
         ":upb_test",
     ],
+)
+
+# copybara:strip_for_google3_begin
+upb_proto_reflection_library(
+    name = "descriptor_upbreflection",
+    deps = ["@com_google_protobuf//:descriptor_proto"],
+)
+
+cc_test(
+    name = "test_encoder",
+    srcs = ["tests/pb/test_encoder.cc"],
     copts = CPPOPTS,
+    deps = [
+        ":descriptor_upbproto",
+        ":descriptor_upbreflection",
+        ":upb",
+        ":upb_cc_bindings",
+        ":upb_pb",
+        ":upb_test",
+    ],
 )
 
 proto_library(
@@ -341,27 +378,31 @@ cc_test(
     srcs = [
         "tests/json/test_json.cc",
     ],
+    copts = CPPOPTS,
     deps = [
-        ":test_json_upbprotoreflection",
         ":test_json_upbproto",
+        ":test_json_upbprotoreflection",
         ":upb_json",
         ":upb_test",
     ],
-    copts = CPPOPTS,
 )
+# copybara:strip_end
 
 upb_proto_library(
     name = "conformance_proto_upb",
+    testonly = 1,
     deps = ["@com_google_protobuf//:conformance_proto"],
 )
 
 upb_proto_library(
     name = "test_messages_proto3_proto_upb",
+    testonly = 1,
     deps = ["@com_google_protobuf//:test_messages_proto3_proto"],
 )
 
 cc_binary(
     name = "conformance_upb",
+    testonly = 1,
     srcs = [
         "tests/conformance_upb.c",
     ],
@@ -376,7 +417,7 @@ cc_binary(
 make_shell_script(
     name = "gen_test_conformance_upb",
     out = "test_conformance_upb.sh",
-    contents = "$(rlocation com_google_protobuf/conformance_test_runner) $(rlocation upb/conformance_upb)",
+    contents = "external/com_google_protobuf/conformance_test_runner ./conformance_upb",
 )
 
 sh_test(
@@ -385,11 +426,12 @@ sh_test(
     data = [
         "tests/conformance_upb_failures.txt",
         ":conformance_upb",
-        "@bazel_tools//tools/bash/runfiles",
         "@com_google_protobuf//:conformance_test_runner",
     ],
 )
 
+# copybara:strip_for_google3_begin
+
 # Amalgamation #################################################################
 
 py_binary(
@@ -397,11 +439,6 @@ py_binary(
     srcs = ["tools/amalgamate.py"],
 )
 
-upb_proto_srcs(
-    name = "descriptor_upbproto_srcs",
-    deps = ["@com_google_protobuf//:descriptor_proto"],
-)
-
 upb_amalgamation(
     name = "gen_amalgamation",
     outs = [
@@ -411,7 +448,7 @@ upb_amalgamation(
     amalgamator = ":amalgamate",
     libs = [
         ":upb",
-        ":descriptor_upbproto_srcs",
+        ":descriptor_upbproto",
         ":reflection",
         ":handlers",
         ":upb_pb",
@@ -494,7 +531,7 @@ filegroup(
         "upbc/**/*",
         "upb/**/*",
         "tests/**/*",
-    ])
+    ]),
 )
 
 make_shell_script(
@@ -506,10 +543,7 @@ make_shell_script(
 sh_test(
     name = "cmake_build",
     srcs = ["run_cmake_build.sh"],
-    data = [
-        ":cmake_files",
-        "@bazel_tools//tools/bash/runfiles",
-    ],
+    data = [":cmake_files"],
 )
 
 # Generated files ##############################################################
@@ -556,7 +590,7 @@ genrule(
 
 genrule(
     name = "copy_protos",
-    srcs = [":descriptor_upbproto_srcs"],
+    srcs = [":descriptor_upbproto"],
     outs = [
         "generated-in/generated_for_cmake/google/protobuf/descriptor.upb.c",
         "generated-in/generated_for_cmake/google/protobuf/descriptor.upb.h",
@@ -568,9 +602,9 @@ generated_file_staleness_test(
     name = "test_generated_files",
     outs = [
         "CMakeLists.txt",
-        "generated_for_cmake/upb/json/parser.c",
         "generated_for_cmake/google/protobuf/descriptor.upb.c",
         "generated_for_cmake/google/protobuf/descriptor.upb.h",
+        "generated_for_cmake/upb/json/parser.c",
     ],
     generated_pattern = "generated-in/%s",
 )
diff --git a/CMakeLists.txt b/CMakeLists.txt
index e6bc5b4..2573173 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -64,8 +64,6 @@ add_library(upb
   upb/decode.c
   upb/encode.c
   upb/msg.c
-  upb/port_def.inc
-  upb/port_undef.inc
   upb/table.c
   upb/table.int.h
   upb/upb.c
@@ -81,6 +79,7 @@ add_library(reflection
   upb/msgfactory.h)
 target_link_libraries(reflection
   descriptor_upbproto
+  table
   upb)
 add_library(table INTERFACE)
 target_link_libraries(table INTERFACE
@@ -89,6 +88,7 @@ add_library(legacy_msg_reflection
   upb/legacy_msg_reflection.c
   upb/legacy_msg_reflection.h)
 target_link_libraries(legacy_msg_reflection
+  table
   upb)
 add_library(handlers
   upb/handlers.c
@@ -98,6 +98,7 @@ add_library(handlers
   upb/sink.h)
 target_link_libraries(handlers
   reflection
+  table
   upb)
 add_library(upb_pb
   upb/pb/compile_decoder.c
@@ -111,7 +112,9 @@ add_library(upb_pb
   upb/pb/encoder.h
   upb/pb/textprinter.h)
 target_link_libraries(upb_pb
+  descriptor_upbproto
   handlers
+  reflection
   table
   upb)
 add_library(upb_json
@@ -124,10 +127,15 @@ target_link_libraries(upb_json
   upb_pb)
 add_library(upb_cc_bindings INTERFACE)
 target_link_libraries(upb_cc_bindings INTERFACE
+  descriptor_upbproto
+  handlers
   upb)
 add_library(upb_test
   tests/testmain.cc
   tests/test_util.h
   tests/upb_test.h)
+target_link_libraries(upb_test
+  handlers
+  upb)
 
 
diff --git a/WORKSPACE b/WORKSPACE
index bcb00f0..74c41c5 100644
--- a/WORKSPACE
+++ b/WORKSPACE
@@ -1,4 +1,3 @@
-
 workspace(name = "upb")
 
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
@@ -6,7 +5,7 @@ load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
 load(":repository_defs.bzl", "bazel_version_repository")
 
 bazel_version_repository(
-    name = "bazel_version"
+    name = "bazel_version",
 )
 
 http_archive(
@@ -23,7 +22,7 @@ http_archive(
 git_repository(
     name = "com_google_protobuf",
     remote = "https://github.com/protocolbuffers/protobuf.git",
-    commit = "78ca77ac8799f67fda7b9a01cc691cd9fe526f25",
+    commit = "d41002663fd04325ead28439dfd5ce2822b0d6fb",
 )
 
 http_archive(
@@ -38,19 +37,19 @@ git_repository(
     name = "absl",
     commit = "070f6e47b33a2909d039e620c873204f78809492",
     remote = "https://github.com/abseil/abseil-cpp.git",
-    shallow_since = "1541627663 -0500"
+    shallow_since = "1541627663 -0500",
 )
 
 http_archive(
     name = "ragel",
-    sha256 = "5f156edb65d20b856d638dd9ee2dfb43285914d9aa2b6ec779dac0270cd56c3f",
     build_file = "//:ragel.BUILD",
+    sha256 = "5f156edb65d20b856d638dd9ee2dfb43285914d9aa2b6ec779dac0270cd56c3f",
     strip_prefix = "ragel-6.10",
     urls = ["http://www.colm.net/files/ragel/ragel-6.10.tar.gz"],
 )
 
 http_archive(
-   name = "bazel_skylib",
-   strip_prefix = "bazel-skylib-master",
-   urls = ["https://github.com/bazelbuild/bazel-skylib/archive/master.tar.gz"],
+    name = "bazel_skylib",
+    strip_prefix = "bazel-skylib-master",
+    urls = ["https://github.com/bazelbuild/bazel-skylib/archive/master.tar.gz"],
 )
diff --git a/build_defs.bzl b/build_defs.bzl
index 38df359..44ef0a3 100644
--- a/build_defs.bzl
+++ b/build_defs.bzl
@@ -1,37 +1,31 @@
+"""Internal rules for building upb."""
 
-load("@bazel_skylib//lib:paths.bzl", "paths")
-load("@bazel_skylib//lib:versions.bzl", "versions")
-load("@bazel_tools//tools/cpp:toolchain_utils.bzl", "find_cpp_toolchain")
-load("@bazel_version//:bazel_version.bzl", "bazel_version")
-
-_shell_find_runfiles = """
-  # --- begin runfiles.bash initialization ---
-  # Copy-pasted from Bazel's Bash runfiles library (tools/bash/runfiles/runfiles.bash).
-  set -euo pipefail
-  if [[ ! -d "${RUNFILES_DIR:-/dev/null}" && ! -f "${RUNFILES_MANIFEST_FILE:-/dev/null}" ]]; then
-    if [[ -f "$0.runfiles_manifest" ]]; then
-      export RUNFILES_MANIFEST_FILE="$0.runfiles_manifest"
-    elif [[ -f "$0.runfiles/MANIFEST" ]]; then
-      export RUNFILES_MANIFEST_FILE="$0.runfiles/MANIFEST"
-    elif [[ -f "$0.runfiles/bazel_tools/tools/bash/runfiles/runfiles.bash" ]]; then
-      export RUNFILES_DIR="$0.runfiles"
-    fi
-  fi
-  if [[ -f "${RUNFILES_DIR:-/dev/null}/bazel_tools/tools/bash/runfiles/runfiles.bash" ]]; then
-    source "${RUNFILES_DIR}/bazel_tools/tools/bash/runfiles/runfiles.bash"
-  elif [[ -f "${RUNFILES_MANIFEST_FILE:-/dev/null}" ]]; then
-    source "$(grep -m1 "^bazel_tools/tools/bash/runfiles/runfiles.bash " \
-              "$RUNFILES_MANIFEST_FILE" | cut -d ' ' -f 2-)"
-  else
-    echo >&2 "ERROR: cannot find @bazel_tools//tools/bash/runfiles:runfiles.bash"
-    exit 1
-  fi
-  # --- end runfiles.bash initialization ---
-"""
+load(":upb_proto_library.bzl", "GeneratedSrcs")
 
 def _librule(name):
     return name + "_lib"
 
+def _get_real_short_path(file):
+    # For some reason, files from other archives have short paths that look like:
+    #   ../com_google_protobuf/google/protobuf/descriptor.proto
+    short_path = file.short_path
+    if short_path.startswith("../"):
+        second_slash = short_path.index("/", 3)
+        short_path = short_path[second_slash + 1:]
+    return short_path
+
+def _get_real_root(file):
+    real_short_path = _get_real_short_path(file)
+    return file.path[:-len(real_short_path) - 1]
+
+def _get_real_roots(files):
+    roots = {}
+    for file in files:
+        real_root = _get_real_root(file)
+        if real_root:
+            roots[real_root] = True
+    return roots.keys()
+
 def lua_cclibrary(name, srcs, hdrs = [], deps = [], luadeps = []):
     lib_rule = name + "_lib"
     so_rule = "lib" + name + ".so"
@@ -93,11 +87,11 @@ def lua_library(name, srcs, strip_prefix, luadeps = []):
     )
 
 def make_shell_script(name, contents, out):
-    script_contents = (_shell_find_runfiles + contents).replace("$", "$$")
+    contents = contents.replace("$", "$$")
     native.genrule(
         name = "gen_" + name,
         outs = [out],
-        cmd = "(cat <<'HEREDOC'\n%s\nHEREDOC\n) > $@" % script_contents,
+        cmd = "(cat <<'HEREDOC'\n%s\nHEREDOC\n) > $@" % contents,
     )
 
 def _lua_binary_or_test(name, luamain, luadeps, rule):
@@ -117,7 +111,7 @@ $(rlocation lua/lua) $(rlocation upb/tools/upbc.lua) "$@"
     rule(
         name = name,
         srcs = [script],
-        data = ["@lua//:lua", "@bazel_tools//tools/bash/runfiles", luamain] + luadeps,
+        data = ["@lua//:lua", luamain] + luadeps,
     )
 
 def lua_binary(name, luamain, luadeps = []):
@@ -180,8 +174,9 @@ SrcList = provider(
 )
 
 def _file_list_aspect_impl(target, ctx):
-    if SrcList in target:
-        return []
+    if GeneratedSrcs in target:
+        srcs = target[GeneratedSrcs]
+        return [SrcList(srcs = srcs.srcs, hdrs = srcs.hdrs)]
 
     srcs = []
     hdrs = []
@@ -189,6 +184,8 @@ def _file_list_aspect_impl(target, ctx):
         srcs += src.files.to_list()
     for hdr in ctx.rule.attr.hdrs:
         hdrs += hdr.files.to_list()
+    for hdr in ctx.rule.attr.textual_hdrs:
+        hdrs += hdr.files.to_list()
     return [SrcList(srcs = srcs, hdrs = hdrs)]
 
 _file_list_aspect = aspect(
@@ -209,6 +206,7 @@ def _upb_amalgamation(ctx):
         progress_message = "Making amalgamation",
         executable = ctx.executable.amalgamator,
     )
+    return []
 
 upb_amalgamation = rule(
     attrs = {
@@ -222,259 +220,6 @@ upb_amalgamation = rule(
     implementation = _upb_amalgamation,
 )
 
-is_bazel = not hasattr(native, "genmpm")
-
-google3_dep_map = {
-    "@absl//absl/base:core_headers": "//third_party/absl/base:core_headers",
-    "@absl//absl/strings": "//third_party/absl/strings",
-    "@com_google_protobuf//:protoc": "//third_party/protobuf:protoc",
-    "@com_google_protobuf//:protobuf": "//third_party/protobuf:protobuf",
-    "@com_google_protobuf//:protoc_lib": "//third_party/protobuf:libprotoc",
-}
-
-def map_dep(dep):
-    if is_bazel:
-        return dep
-    else:
-        return google3_dep_map[dep]
-
-def _get_real_short_path(file):
-    # For some reason, files from other archives have short paths that look like:
-    #   ../com_google_protobuf/google/protobuf/descriptor.proto
-    short_path = file.short_path
-    if short_path.startswith("../"):
-        second_slash = short_path.index("/", 3)
-        short_path = short_path[second_slash + 1:]
-    return short_path
-
-def _get_real_root(file):
-    real_short_path = _get_real_short_path(file)
-    return file.path[:-len(real_short_path) - 1]
-
-def _get_real_roots(files):
-    roots = {}
-    for file in files:
-        real_root = _get_real_root(file)
-        if real_root:
-            roots[real_root] = True
-    return roots.keys()
-
-def _generate_output_file(ctx, src, extension):
-    real_short_path = _get_real_short_path(src)
-    output_filename = paths.replace_extension(real_short_path, extension)
-    ret = ctx.new_file(ctx.genfiles_dir, output_filename)
-    return ret
-
-def filter_none(elems):
-    out = []
-    for elem in elems:
-        if elem:
-            out.append(elem)
-    return out
-
-# upb_proto_library() rule
-
-def cc_library_func(ctx, name, hdrs, srcs, dep_ccinfos):
-    compilation_contexts = [info.compilation_context for info in dep_ccinfos]
-    linking_contexts = [info.linking_context for info in dep_ccinfos]
-    toolchain = find_cpp_toolchain(ctx)
-    feature_configuration = cc_common.configure_features(
-        cc_toolchain = toolchain,
-        requested_features = ctx.features,
-        unsupported_features = ctx.disabled_features,
-    )
-
-    if is_bazel:
-        if bazel_version == "0.24.1":
-            # Compatibility code until gRPC is on 0.25.2 or later.
-            compilation_info = cc_common.compile(
-                ctx = ctx,
-                feature_configuration = feature_configuration,
-                cc_toolchain = toolchain,
-                srcs = srcs,
-                hdrs = hdrs,
-                compilation_contexts = compilation_contexts,
-            )
-            linking_info = cc_common.link(
-                ctx = ctx,
-                feature_configuration = feature_configuration,
-                cc_toolchain = toolchain,
-                cc_compilation_outputs = compilation_info.cc_compilation_outputs,
-                linking_contexts = linking_contexts,
-            )
-            return CcInfo(
-                compilation_context = compilation_info.compilation_context,
-                linking_context = linking_info.linking_context,
-            )
-
-        if not versions.is_at_least("0.25.2", bazel_version):
-            fail("upb requires Bazel >=0.25.2 or 0.24.1")
-
-    (compilation_context, compilation_outputs) = cc_common.compile(
-        actions = ctx.actions,
-        feature_configuration = feature_configuration,
-        cc_toolchain = toolchain,
-        name = name,
-        srcs = srcs,
-        public_hdrs = hdrs,
-        compilation_contexts = compilation_contexts,
-    )
-    (linking_context, linking_outputs) = cc_common.create_linking_context_from_compilation_outputs(
-        actions = ctx.actions,
-        name = name,
-        feature_configuration = feature_configuration,
-        cc_toolchain = toolchain,
-        compilation_outputs = compilation_outputs,
-        linking_contexts = linking_contexts,
-    )
-
-    return CcInfo(
-        compilation_context = compilation_context,
-        linking_context = linking_context,
-    )
-
-def _compile_upb_protos(ctx, proto_info, proto_sources, ext):
-    srcs = [_generate_output_file(ctx, name, ext + ".c") for name in proto_sources]
-    hdrs = [_generate_output_file(ctx, name, ext + ".h") for name in proto_sources]
-    transitive_sets = list(proto_info.transitive_descriptor_sets)
-    ctx.actions.run(
-        inputs = depset(
-            direct = [ctx.executable._upbc, proto_info.direct_descriptor_set],
-            transitive = [proto_info.transitive_descriptor_sets],
-        ),
-        outputs = srcs + hdrs,
-        executable = ctx.executable._protoc,
-        arguments = [
-                        "--upb_out=" + _get_real_root(srcs[0]),
-                        "--plugin=protoc-gen-upb=" + ctx.executable._upbc.path,
-                        "--descriptor_set_in=" + ":".join([f.path for f in transitive_sets]),
-                    ] +
-                    [_get_real_short_path(file) for file in proto_sources],
-                    progress_message = "Generating upb protos for :" + ctx.label.name,
-    )
-    return SrcList(srcs = srcs, hdrs = hdrs)
-
-# upb_proto_library() shared code #############################################
-
-# Can share these with upb_proto_library() once cc_common.link() supports name
-# param.
-
-def _upb_proto_rule_impl(ctx):
-    if len(ctx.attr.deps) != 1:
-        fail("only one deps dependency allowed.")
-    dep = ctx.attr.deps[0]
-    if CcInfo not in dep:
-        fail("proto_library rule must generate CcInfo (aspect should have handled this).")
-    lib = dep[CcInfo].linking_context.libraries_to_link[0]
-    files = filter_none([
-        lib.static_library,
-        lib.pic_static_library,
-        lib.dynamic_library,
-    ])
-    return [
-        DefaultInfo(files = depset(files)),
-        dep[CcInfo],
-    ]
-
-def _upb_proto_aspect_impl(target, ctx):
-    proto_info = target[ProtoInfo]
-    files = _compile_upb_protos(ctx, proto_info, proto_info.direct_sources, ctx.attr._ext)
-    deps = ctx.rule.attr.deps + [ctx.attr._upb]
-    dep_ccinfos = [dep[CcInfo] for dep in deps if CcInfo in dep]
-    cc_info = cc_library_func(
-        ctx = ctx,
-        name = ctx.rule.attr.name,
-        hdrs = files.hdrs,
-        srcs = files.srcs,
-        dep_ccinfos = dep_ccinfos,
-    )
-    return [cc_info]
-
-# upb_proto_library() ##########################################################
-
-_upb_proto_library_aspect = aspect(
-    attrs = {
-        "_upbc": attr.label(
-            executable = True,
-            cfg = "host",
-            default = ":protoc-gen-upb",
-        ),
-        "_protoc": attr.label(
-            executable = True,
-            cfg = "host",
-            default = map_dep("@com_google_protobuf//:protoc"),
-        ),
-        "_cc_toolchain": attr.label(default = "@bazel_tools//tools/cpp:current_cc_toolchain"),
-        "_upb": attr.label(default = ":upb"),
-        "_ext": attr.string(default = ".upb"),
-    },
-    implementation = _upb_proto_aspect_impl,
-    attr_aspects = ["deps"],
-    fragments = ["cpp"],
-)
-
-upb_proto_library = rule(
-    output_to_genfiles = True,
-    implementation = _upb_proto_rule_impl,
-    attrs = {
-        "deps": attr.label_list(
-            aspects = [_upb_proto_library_aspect],
-            allow_rules = ["proto_library"],
-            providers = [ProtoInfo],
-        ),
-    },
-)
-
-# upb_proto_srcs() #############################################################
-
-def _upb_proto_srcs_impl(ctx):
-    srcs = []
-    hdrs = []
-    for dep in ctx.attr.deps:
-        if hasattr(dep, "proto"):
-            proto_info = dep[ProtoInfo]
-            files = _compile_upb_protos(ctx, proto_info, proto_info.transitive_sources, ctx.attr.ext)
-            srcs += files.srcs
-            hdrs += files.hdrs
-    return [
-        SrcList(srcs = srcs, hdrs = hdrs),
-        DefaultInfo(files = depset(srcs + hdrs)),
-    ]
-
-upb_proto_srcs = rule(
-    attrs = {
-        "_upbc": attr.label(
-            executable = True,
-            cfg = "host",
-            default = ":protoc-gen-upb",
-        ),
-        "_protoc": attr.label(
-            executable = True,
-            cfg = "host",
-            default = map_dep("@com_google_protobuf//:protoc"),
-        ),
-        "deps": attr.label_list(),
-        "ext": attr.string(default = ".upb")
-    },
-    implementation = _upb_proto_srcs_impl,
-)
-
-# upb_proto_reflection_library() ###############################################
-
-def upb_proto_reflection_library(name, deps):
-    srcs_rule = name + "_defsrcs.cc"
-    upb_proto_srcs(
-        name = srcs_rule,
-        deps = deps,
-        ext = ".upbdefs",
-    )
-    native.cc_library(
-        name = name,
-        srcs = [":" + srcs_rule],
-        deps = [":upb", ":reflection"],
-        copts = ["-Ibazel-out/k8-fastbuild/bin"],
-    )
-
 def licenses(*args):
     # No-op (for Google-internal usage).
     pass
diff --git a/generated_for_cmake/google/protobuf/descriptor.upb.h b/generated_for_cmake/google/protobuf/descriptor.upb.h
index 7f164fb..3016c91 100644
--- a/generated_for_cmake/google/protobuf/descriptor.upb.h
+++ b/generated_for_cmake/google/protobuf/descriptor.upb.h
@@ -10,12 +10,12 @@
 #define GOOGLE_PROTOBUF_DESCRIPTOR_PROTO_UPB_H_
 
 #include "upb/generated_util.h"
-
 #include "upb/msg.h"
-
 #include "upb/decode.h"
 #include "upb/encode.h"
+
 #include "upb/port_def.inc"
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -102,8 +102,6 @@ extern const upb_msglayout google_protobuf_SourceCodeInfo_Location_msginit;
 extern const upb_msglayout google_protobuf_GeneratedCodeInfo_msginit;
 extern const upb_msglayout google_protobuf_GeneratedCodeInfo_Annotation_msginit;
 
-/* Enums */
-
 typedef enum {
   google_protobuf_FieldDescriptorProto_LABEL_OPTIONAL = 1,
   google_protobuf_FieldDescriptorProto_LABEL_REQUIRED = 2,
@@ -186,7 +184,6 @@ UPB_INLINE struct google_protobuf_FileDescriptorProto* google_protobuf_FileDescr
   return sub;
 }
 
-
 /* google.protobuf.FileDescriptorProto */
 
 UPB_INLINE google_protobuf_FileDescriptorProto *google_protobuf_FileDescriptorProto_new(upb_arena *arena) {
@@ -340,7 +337,6 @@ UPB_INLINE void google_protobuf_FileDescriptorProto_set_syntax(google_protobuf_F
   UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(20, 40)) = value;
 }
 
-
 /* google.protobuf.DescriptorProto */
 
 UPB_INLINE google_protobuf_DescriptorProto *google_protobuf_DescriptorProto_new(upb_arena *arena) {
@@ -487,7 +483,6 @@ UPB_INLINE bool google_protobuf_DescriptorProto_add_reserved_name(google_protobu
       msg, UPB_SIZE(44, 88), UPB_SIZE(8, 16), UPB_TYPE_STRING, &val, arena);
 }
 
-
 /* google.protobuf.DescriptorProto.ExtensionRange */
 
 UPB_INLINE google_protobuf_DescriptorProto_ExtensionRange *google_protobuf_DescriptorProto_ExtensionRange_new(upb_arena *arena) {
@@ -531,7 +526,6 @@ UPB_INLINE struct google_protobuf_ExtensionRangeOptions* google_protobuf_Descrip
   return sub;
 }
 
-
 /* google.protobuf.DescriptorProto.ReservedRange */
 
 UPB_INLINE google_protobuf_DescriptorProto_ReservedRange *google_protobuf_DescriptorProto_ReservedRange_new(upb_arena *arena) {
@@ -560,7 +554,6 @@ UPB_INLINE void google_protobuf_DescriptorProto_ReservedRange_set_end(google_pro
   UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)) = value;
 }
 
-
 /* google.protobuf.ExtensionRangeOptions */
 
 UPB_INLINE google_protobuf_ExtensionRangeOptions *google_protobuf_ExtensionRangeOptions_new(upb_arena *arena) {
@@ -591,7 +584,6 @@ UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_Extension
   return sub;
 }
 
-
 /* google.protobuf.FieldDescriptorProto */
 
 UPB_INLINE google_protobuf_FieldDescriptorProto *google_protobuf_FieldDescriptorProto_new(upb_arena *arena) {
@@ -677,7 +669,6 @@ UPB_INLINE void google_protobuf_FieldDescriptorProto_set_json_name(google_protob
   UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(64, 96)) = value;
 }
 
-
 /* google.protobuf.OneofDescriptorProto */
 
 UPB_INLINE google_protobuf_OneofDescriptorProto *google_protobuf_OneofDescriptorProto_new(upb_arena *arena) {
@@ -715,7 +706,6 @@ UPB_INLINE struct google_protobuf_OneofOptions* google_protobuf_OneofDescriptorP
   return sub;
 }
 
-
 /* google.protobuf.EnumDescriptorProto */
 
 UPB_INLINE google_protobuf_EnumDescriptorProto *google_protobuf_EnumDescriptorProto_new(upb_arena *arena) {
@@ -792,7 +782,6 @@ UPB_INLINE bool google_protobuf_EnumDescriptorProto_add_reserved_name(google_pro
       msg, UPB_SIZE(24, 48), UPB_SIZE(8, 16), UPB_TYPE_STRING, &val, arena);
 }
 
-
 /* google.protobuf.EnumDescriptorProto.EnumReservedRange */
 
 UPB_INLINE google_protobuf_EnumDescriptorProto_EnumReservedRange *google_protobuf_EnumDescriptorProto_EnumReservedRange_new(upb_arena *arena) {
@@ -821,7 +810,6 @@ UPB_INLINE void google_protobuf_EnumDescriptorProto_EnumReservedRange_set_end(go
   UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)) = value;
 }
 
-
 /* google.protobuf.EnumValueDescriptorProto */
 
 UPB_INLINE google_protobuf_EnumValueDescriptorProto *google_protobuf_EnumValueDescriptorProto_new(upb_arena *arena) {
@@ -865,7 +853,6 @@ UPB_INLINE struct google_protobuf_EnumValueOptions* google_protobuf_EnumValueDes
   return sub;
 }
 
-
 /* google.protobuf.ServiceDescriptorProto */
 
 UPB_INLINE google_protobuf_ServiceDescriptorProto *google_protobuf_ServiceDescriptorProto_new(upb_arena *arena) {
@@ -917,7 +904,6 @@ UPB_INLINE struct google_protobuf_ServiceOptions* google_protobuf_ServiceDescrip
   return sub;
 }
 
-
 /* google.protobuf.MethodDescriptorProto */
 
 UPB_INLINE google_protobuf_MethodDescriptorProto *google_protobuf_MethodDescriptorProto_new(upb_arena *arena) {
@@ -979,7 +965,6 @@ UPB_INLINE void google_protobuf_MethodDescriptorProto_set_server_streaming(googl
   UPB_FIELD_AT(msg, bool, UPB_SIZE(2, 2)) = value;
 }
 
-
 /* google.protobuf.FileOptions */
 
 UPB_INLINE google_protobuf_FileOptions *google_protobuf_FileOptions_new(upb_arena *arena) {
@@ -1130,7 +1115,6 @@ UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_FileOptio
   return sub;
 }
 
-
 /* google.protobuf.MessageOptions */
 
 UPB_INLINE google_protobuf_MessageOptions *google_protobuf_MessageOptions_new(upb_arena *arena) {
@@ -1185,7 +1169,6 @@ UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_MessageOp
   return sub;
 }
 
-
 /* google.protobuf.FieldOptions */
 
 UPB_INLINE google_protobuf_FieldOptions *google_protobuf_FieldOptions_new(upb_arena *arena) {
@@ -1252,7 +1235,6 @@ UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_FieldOpti
   return sub;
 }
 
-
 /* google.protobuf.OneofOptions */
 
 UPB_INLINE google_protobuf_OneofOptions *google_protobuf_OneofOptions_new(upb_arena *arena) {
@@ -1283,7 +1265,6 @@ UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_OneofOpti
   return sub;
 }
 
-
 /* google.protobuf.EnumOptions */
 
 UPB_INLINE google_protobuf_EnumOptions *google_protobuf_EnumOptions_new(upb_arena *arena) {
@@ -1326,7 +1307,6 @@ UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_EnumOptio
   return sub;
 }
 
-
 /* google.protobuf.EnumValueOptions */
 
 UPB_INLINE google_protobuf_EnumValueOptions *google_protobuf_EnumValueOptions_new(upb_arena *arena) {
@@ -1363,7 +1343,6 @@ UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_EnumValue
   return sub;
 }
 
-
 /* google.protobuf.ServiceOptions */
 
 UPB_INLINE google_protobuf_ServiceOptions *google_protobuf_ServiceOptions_new(upb_arena *arena) {
@@ -1400,7 +1379,6 @@ UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_ServiceOp
   return sub;
 }
 
-
 /* google.protobuf.MethodOptions */
 
 UPB_INLINE google_protobuf_MethodOptions *google_protobuf_MethodOptions_new(upb_arena *arena) {
@@ -1443,7 +1421,6 @@ UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_MethodOpt
   return sub;
 }
 
-
 /* google.protobuf.UninterpretedOption */
 
 UPB_INLINE google_protobuf_UninterpretedOption *google_protobuf_UninterpretedOption_new(upb_arena *arena) {
@@ -1510,7 +1487,6 @@ UPB_INLINE void google_protobuf_UninterpretedOption_set_aggregate_value(google_p
   UPB_FIELD_AT(msg, upb_strview, UPB_SIZE(48, 64)) = value;
 }
 
-
 /* google.protobuf.UninterpretedOption.NamePart */
 
 UPB_INLINE google_protobuf_UninterpretedOption_NamePart *google_protobuf_UninterpretedOption_NamePart_new(upb_arena *arena) {
@@ -1539,7 +1515,6 @@ UPB_INLINE void google_protobuf_UninterpretedOption_NamePart_set_is_extension(go
   UPB_FIELD_AT(msg, bool, UPB_SIZE(1, 1)) = value;
 }
 
-
 /* google.protobuf.SourceCodeInfo */
 
 UPB_INLINE google_protobuf_SourceCodeInfo *google_protobuf_SourceCodeInfo_new(upb_arena *arena) {
@@ -1570,7 +1545,6 @@ UPB_INLINE struct google_protobuf_SourceCodeInfo_Location* google_protobuf_Sourc
   return sub;
 }
 
-
 /* google.protobuf.SourceCodeInfo.Location */
 
 UPB_INLINE google_protobuf_SourceCodeInfo_Location *google_protobuf_SourceCodeInfo_Location_new(upb_arena *arena) {
@@ -1632,7 +1606,6 @@ UPB_INLINE bool google_protobuf_SourceCodeInfo_Location_add_leading_detached_com
       msg, UPB_SIZE(28, 56), UPB_SIZE(8, 16), UPB_TYPE_STRING, &val, arena);
 }
 
-
 /* google.protobuf.GeneratedCodeInfo */
 
 UPB_INLINE google_protobuf_GeneratedCodeInfo *google_protobuf_GeneratedCodeInfo_new(upb_arena *arena) {
@@ -1663,7 +1636,6 @@ UPB_INLINE struct google_protobuf_GeneratedCodeInfo_Annotation* google_protobuf_
   return sub;
 }
 
-
 /* google.protobuf.GeneratedCodeInfo.Annotation */
 
 UPB_INLINE google_protobuf_GeneratedCodeInfo_Annotation *google_protobuf_GeneratedCodeInfo_Annotation_new(upb_arena *arena) {
@@ -1709,7 +1681,6 @@ UPB_INLINE void google_protobuf_GeneratedCodeInfo_Annotation_set_end(google_prot
   UPB_FIELD_AT(msg, int32_t, UPB_SIZE(8, 8)) = value;
 }
 
-
 #ifdef __cplusplus
 }  /* extern "C" */
 #endif
diff --git a/repository_defs.bzl b/repository_defs.bzl
index 5bbc9cb..7b6e78e 100644
--- a/repository_defs.bzl
+++ b/repository_defs.bzl
@@ -1,4 +1,3 @@
-
 # A hacky way to work around the fact that native.bazel_version is only
 # available from WORKSPACE macros, not BUILD macros or rules.
 #
@@ -11,6 +10,6 @@ def _impl(repository_ctx):
     repository_ctx.file("BUILD", "")
 
 bazel_version_repository = repository_rule(
-    implementation=_impl,
-    local=True,
+    implementation = _impl,
+    local = True,
 )
diff --git a/tests/conformance_upb.c b/tests/conformance_upb.c
index 782346f..36e550e 100644
--- a/tests/conformance_upb.c
+++ b/tests/conformance_upb.c
@@ -75,21 +75,16 @@ void DoTest(
       break;
     }
 
-    case conformance_ConformanceRequest_payload_json_payload: {
-      static const char msg[] = "JSON support not yet implemented.";
-      conformance_ConformanceResponse_set_skipped(
-          response, upb_strview_make(msg, sizeof(msg)));
-      return;
-    }
-
     case conformance_ConformanceRequest_payload_NOT_SET:
       fprintf(stderr, "conformance_upb: Request didn't have payload.\n");
       return;
 
-    default:
-      fprintf(stderr, "conformance_upb: Unexpected case: %d\n",
-              conformance_ConformanceRequest_payload_case(request));
-      exit(1);
+    default: {
+      static const char msg[] = "Unsupported input format.";
+      conformance_ConformanceResponse_set_skipped(
+          response, upb_strview_make(msg, sizeof(msg)));
+      return;
+    }
   }
 
   switch (conformance_ConformanceRequest_requested_output_format(request)) {
@@ -113,17 +108,12 @@ void DoTest(
       break;
     }
 
-    case conformance_JSON: {
-      static const char msg[] = "JSON support not yet implemented.";
+    default: {
+      static const char msg[] = "Unsupported output format.";
       conformance_ConformanceResponse_set_skipped(
           response, upb_strview_make(msg, sizeof(msg)));
-      break;
+      return;
     }
-
-    default:
-      fprintf(stderr, "conformance_upb: Unknown output format: %d\n",
-              conformance_ConformanceRequest_requested_output_format(request));
-      exit(1);
   }
 
   return;
diff --git a/tests/test_cpp.cc b/tests/test_cpp.cc
index 8feb6e2..abbafda 100644
--- a/tests/test_cpp.cc
+++ b/tests/test_cpp.cc
@@ -12,14 +12,13 @@
 #include <sstream>
 
 #include "tests/test_cpp.upbdefs.h"
+#include "tests/upb_test.h"
 #include "upb/def.h"
 #include "upb/handlers.h"
 #include "upb/pb/decoder.h"
 #include "upb/pb/textprinter.h"
-#include "upb/upb.h"
-#include "upb_test.h"
-
 #include "upb/port_def.inc"
+#include "upb/upb.h"
 
 template <class T>
 void AssertInsert(T* const container, const typename T::value_type& val) {
diff --git a/upb/handlers-inl.h b/upb/handlers-inl.h
index 40a0047..8f8634b 100644
--- a/upb/handlers-inl.h
+++ b/upb/handlers-inl.h
@@ -10,6 +10,8 @@
 #include <stddef.h>
 #include "upb/handlers.h"
 
+#include "upb/port_def.inc"
+
 #ifdef __cplusplus
 
 /* Type detection and typedefs for integer types.
@@ -916,4 +918,6 @@ inline void Handler<T>::AddCleanup(upb_handlers* h) const {
 #undef UPB_INT64ALT_T
 #undef UPB_UINT64ALT_T
 
+#include "upb/port_undef.inc"
+
 #endif  /* UPB_HANDLERS_INL_H_ */
diff --git a/upb/handlers.h b/upb/handlers.h
index 856be31..2d2380b 100644
--- a/upb/handlers.h
+++ b/upb/handlers.h
@@ -725,8 +725,8 @@ bool upb_msg_getscalarhandlerdata(const upb_handlers *h,
 }  /* extern "C" */
 #endif
 
-#include "upb/handlers-inl.h"
-
 #include "upb/port_undef.inc"
 
+#include "upb/handlers-inl.h"
+
 #endif  /* UPB_HANDLERS_H */
diff --git a/upb_proto_library.bzl b/upb_proto_library.bzl
new file mode 100644
index 0000000..962facd
--- /dev/null
+++ b/upb_proto_library.bzl
@@ -0,0 +1,291 @@
+"""Public rules for using upb protos:
+  - upb_proto_library()
+  - upb_proto_reflection_library()
+"""
+
+load("@bazel_skylib//lib:paths.bzl", "paths")
+load("@bazel_tools//tools/cpp:toolchain_utils.bzl", "find_cpp_toolchain")
+
+# copybara:strip_for_google3_begin
+load("@bazel_skylib//lib:versions.bzl", "versions")
+load("@bazel_version//:bazel_version.bzl", "bazel_version")
+# copybara:strip_end
+
+# Generic support code #########################################################
+
+_is_bazel = not hasattr(native, "genmpm")
+
+def _get_real_short_path(file):
+    # For some reason, files from other archives have short paths that look like:
+    #   ../com_google_protobuf/google/protobuf/descriptor.proto
+    short_path = file.short_path
+    if short_path.startswith("../"):
+        second_slash = short_path.index("/", 3)
+        short_path = short_path[second_slash + 1:]
+    return short_path
+
+def _get_real_root(file):
+    real_short_path = _get_real_short_path(file)
+    return file.path[:-len(real_short_path) - 1]
+
+def _get_real_roots(files):
+    roots = {}
+    for file in files:
+        real_root = _get_real_root(file)
+        if real_root:
+            roots[real_root] = True
+    return roots.keys()
+
+def _generate_output_file(ctx, src, extension):
+    if _is_bazel:
+        real_short_path = _get_real_short_path(src)
+    else:
+        real_short_path = paths.relativize(src.short_path, ctx.label.package)
+    output_filename = paths.replace_extension(real_short_path, extension)
+    ret = ctx.new_file(ctx.genfiles_dir, output_filename)
+    return ret
+
+def _filter_none(elems):
+    out = []
+    for elem in elems:
+        if elem:
+            out.append(elem)
+    return out
+
+def _cc_library_func(ctx, name, hdrs, srcs, dep_ccinfos):
+    """Like cc_library(), but callable from rules.
+
+    Args:
+      ctx: Rule context.
+      name: Unique name used to generate output files.
+      hdrs: Public headers that can be #included from other rules.
+      srcs: C/C++ source files.
+      dep_ccinfos: CcInfo providers of dependencies we should build/link against.
+
+    Returns:
+      CcInfo provider for this compilation.
+    """
+
+    compilation_contexts = [info.compilation_context for info in dep_ccinfos]
+    linking_contexts = [info.linking_context for info in dep_ccinfos]
+    toolchain = find_cpp_toolchain(ctx)
+    feature_configuration = cc_common.configure_features(
+        cc_toolchain = toolchain,
+        requested_features = ctx.features,
+        unsupported_features = ctx.disabled_features,
+    )
+
+    # copybara:strip_for_google3_begin
+    if bazel_version == "0.24.1":
+        # Compatibility code until gRPC is on 0.25.2 or later.
+        compilation_info = cc_common.compile(
+            ctx = ctx,
+            feature_configuration = feature_configuration,
+            cc_toolchain = toolchain,
+            srcs = srcs,
+            hdrs = hdrs,
+            compilation_contexts = compilation_contexts,
+        )
+        linking_info = cc_common.link(
+            ctx = ctx,
+            feature_configuration = feature_configuration,
+            cc_toolchain = toolchain,
+            cc_compilation_outputs = compilation_info.cc_compilation_outputs,
+            linking_contexts = linking_contexts,
+        )
+        return CcInfo(
+            compilation_context = compilation_info.compilation_context,
+            linking_context = linking_info.linking_context,
+        )
+
+    if not versions.is_at_least("0.25.2", bazel_version):
+        fail("upb requires Bazel >=0.25.2 or 0.24.1")
+
+    # copybara:strip_end
+
+    blaze_only_args = {}
+
+    if not _is_bazel:
+        blaze_only_args["grep_includes"] = ctx.file._grep_includes
+
+    (compilation_context, compilation_outputs) = cc_common.compile(
+        actions = ctx.actions,
+        feature_configuration = feature_configuration,
+        cc_toolchain = toolchain,
+        name = name,
+        srcs = srcs,
+        public_hdrs = hdrs,
+        compilation_contexts = compilation_contexts,
+        **blaze_only_args
+    )
+    (linking_context, linking_outputs) = cc_common.create_linking_context_from_compilation_outputs(
+        actions = ctx.actions,
+        name = name,
+        feature_configuration = feature_configuration,
+        cc_toolchain = toolchain,
+        compilation_outputs = compilation_outputs,
+        linking_contexts = linking_contexts,
+        **blaze_only_args
+    )
+
+    return CcInfo(
+        compilation_context = compilation_context,
+        linking_context = linking_context,
+    )
+
+# upb_proto_library / upb_proto_reflection_library shared code #################
+
+GeneratedSrcs = provider(
+    fields = {
+        "srcs": "list of srcs",
+        "hdrs": "list of hdrs",
+    },
+)
+
+_WrappedCcInfo = provider(fields = ["cc_info"])
+_WrappedGeneratedSrcs = provider(fields = ["srcs"])
+
+def _compile_upb_protos(ctx, proto_info, proto_sources, ext):
+    srcs = [_generate_output_file(ctx, name, ext + ".c") for name in proto_sources]
+    hdrs = [_generate_output_file(ctx, name, ext + ".h") for name in proto_sources]
+    transitive_sets = list(proto_info.transitive_descriptor_sets)
+    ctx.actions.run(
+        inputs = depset(
+            direct = [ctx.executable._upbc, proto_info.direct_descriptor_set],
+            transitive = [proto_info.transitive_descriptor_sets],
+        ),
+        outputs = srcs + hdrs,
+        executable = ctx.executable._protoc,
+        arguments = [
+                        "--upb_out=" + _get_real_root(srcs[0]),
+                        "--plugin=protoc-gen-upb=" + ctx.executable._upbc.path,
+                        "--descriptor_set_in=" + ":".join([f.path for f in transitive_sets]),
+                    ] +
+                    [_get_real_short_path(file) for file in proto_sources],
+        progress_message = "Generating upb protos for :" + ctx.label.name,
+    )
+    return GeneratedSrcs(srcs = srcs, hdrs = hdrs)
+
+def _upb_proto_rule_impl(ctx):
+    if len(ctx.attr.deps) != 1:
+        fail("only one deps dependency allowed.")
+    dep = ctx.attr.deps[0]
+    if _WrappedCcInfo not in dep or _WrappedGeneratedSrcs not in dep:
+        fail("proto_library rule must generate _WrappedCcInfo and " +
+             "_WrappedGeneratedSrcs (aspect should have handled this).")
+    cc_info = dep[_WrappedCcInfo].cc_info
+    srcs = dep[_WrappedGeneratedSrcs].srcs
+    lib = cc_info.linking_context.libraries_to_link[0]
+    files = _filter_none([
+        lib.static_library,
+        lib.pic_static_library,
+        lib.dynamic_library,
+    ])
+    return [
+        DefaultInfo(files = depset(files + srcs.hdrs + srcs.srcs)),
+        srcs,
+        cc_info,
+    ]
+
+def _upb_proto_aspect_impl(target, ctx):
+    proto_info = target[ProtoInfo]
+    files = _compile_upb_protos(ctx, proto_info, proto_info.direct_sources, ctx.attr._ext)
+    deps = ctx.rule.attr.deps + ctx.attr._upb
+    dep_ccinfos = [dep[CcInfo] for dep in deps if CcInfo in dep]
+    dep_ccinfos += [dep[_WrappedCcInfo].cc_info for dep in deps if _WrappedCcInfo in dep]
+    cc_info = _cc_library_func(
+        ctx = ctx,
+        name = ctx.rule.attr.name + ctx.attr._ext,
+        hdrs = files.hdrs,
+        srcs = files.srcs,
+        dep_ccinfos = dep_ccinfos,
+    )
+    return [_WrappedCcInfo(cc_info = cc_info), _WrappedGeneratedSrcs(srcs = files)]
+
+def _maybe_add(d):
+    if not _is_bazel:
+        d["_grep_includes"] = attr.label(
+            allow_single_file = True,
+            cfg = "host",
+            default = "//tools/cpp:grep-includes",
+        )
+    return d
+
+# upb_proto_library() ##########################################################
+
+_upb_proto_library_aspect = aspect(
+    attrs = _maybe_add({
+        "_upbc": attr.label(
+            executable = True,
+            cfg = "host",
+            default = ":protoc-gen-upb",
+        ),
+        "_protoc": attr.label(
+            executable = True,
+            cfg = "host",
+            default = "@com_google_protobuf//:protoc",
+        ),
+        "_cc_toolchain": attr.label(
+            default = "@bazel_tools//tools/cpp:current_cc_toolchain",
+        ),
+        "_upb": attr.label_list(default = [":upb"]),
+        "_ext": attr.string(default = ".upb"),
+    }),
+    implementation = _upb_proto_aspect_impl,
+    attr_aspects = ["deps"],
+    fragments = ["cpp"],
+)
+
+upb_proto_library = rule(
+    output_to_genfiles = True,
+    implementation = _upb_proto_rule_impl,
+    attrs = {
+        "deps": attr.label_list(
+            aspects = [_upb_proto_library_aspect],
+            allow_rules = ["proto_library"],
+            providers = [ProtoInfo],
+        ),
+    },
+)
+
+# upb_proto_reflection_library() ###############################################
+
+_upb_proto_reflection_library_aspect = aspect(
+    attrs = _maybe_add({
+        "_upbc": attr.label(
+            executable = True,
+            cfg = "host",
+            default = ":protoc-gen-upb",
+        ),
+        "_protoc": attr.label(
+            executable = True,
+            cfg = "host",
+            default = "@com_google_protobuf//:protoc",
+        ),
+        "_cc_toolchain": attr.label(
+            default = "@bazel_tools//tools/cpp:current_cc_toolchain",
+        ),
+        "_upb": attr.label_list(
+            default = [
+                ":upb",
+                ":reflection",
+            ],
+        ),
+        "_ext": attr.string(default = ".upbdefs"),
+    }),
+    implementation = _upb_proto_aspect_impl,
+    attr_aspects = ["deps"],
+    fragments = ["cpp"],
+)
+
+upb_proto_reflection_library = rule(
+    output_to_genfiles = True,
+    implementation = _upb_proto_rule_impl,
+    attrs = {
+        "deps": attr.label_list(
+            aspects = [_upb_proto_reflection_library_aspect],
+            allow_rules = ["proto_library"],
+            providers = [ProtoInfo],
+        ),
+    },
+)
diff --git a/upbc/generator.cc b/upbc/generator.cc
index 5843597..53d849e 100644
--- a/upbc/generator.cc
+++ b/upbc/generator.cc
@@ -1,8 +1,7 @@
 
-#include <unordered_map>
-#include <unordered_set>
 #include <memory>
 
+#include "absl/container/flat_hash_map.h"
 #include "absl/strings/ascii.h"
 #include "absl/strings/str_replace.h"
 #include "absl/strings/substitute.h"
@@ -488,7 +487,7 @@ void GenerateMessageInHeader(const protobuf::Descriptor* message, Output& output
     }
   }
 
-  output("\n\n");
+  output("\n");
 }
 
 void WriteHeader(const protobuf::FileDescriptor* file, Output& output) {
@@ -496,15 +495,30 @@ void WriteHeader(const protobuf::FileDescriptor* file, Output& output) {
   output(
       "#ifndef $0_UPB_H_\n"
       "#define $0_UPB_H_\n\n"
-      "#include \"upb/generated_util.h\"\n\n"
-      "#include \"upb/msg.h\"\n\n"
+      "#include \"upb/generated_util.h\"\n"
+      "#include \"upb/msg.h\"\n"
       "#include \"upb/decode.h\"\n"
-      "#include \"upb/encode.h\"\n"
+      "#include \"upb/encode.h\"\n\n",
+      ToPreproc(file->name()));
+
+  for (int i = 0; i < file->public_dependency_count(); i++) {
+    const auto& name = file->public_dependency(i)->name();
+    if (i == 0) {
+      output("/* Public Imports. */\n");
+    }
+    output("#include \"$0\"\n", HeaderFilename(name));
+    if (i == file->public_dependency_count() - 1) {
+      output("\n");
+    }
+  }
+
+  output(
       "#include \"upb/port_def.inc\"\n"
+      "\n"
       "#ifdef __cplusplus\n"
       "extern \"C\" {\n"
-      "#endif\n\n",
-      ToPreproc(file->name()));
+      "#endif\n"
+      "\n");
 
   std::vector<const protobuf::Descriptor*> this_file_messages =
       SortedMessages(file);
@@ -541,12 +555,13 @@ void WriteHeader(const protobuf::FileDescriptor* file, Output& output) {
     output("extern const upb_msglayout $0;\n", MessageInit(pair.second));
   }
 
+  if (!this_file_messages.empty()) {
+    output("\n");
+  }
+
   std::vector<const protobuf::EnumDescriptor*> this_file_enums =
       SortedEnums(file);
 
-  output(
-      "\n"
-      "/* Enums */\n\n");
   for (auto enumdesc : this_file_enums) {
     output("typedef enum {\n");
     DumpEnumValues(enumdesc, output);
@@ -594,7 +609,7 @@ void WriteSource(const protobuf::FileDescriptor* file, Output& output) {
     std::string fields_array_ref = "NULL";
     std::string submsgs_array_ref = "NULL";
     std::string oneofs_array_ref = "NULL";
-    std::unordered_map<const protobuf::Descriptor*, int> submsg_indexes;
+    absl::flat_hash_map<const protobuf::Descriptor*, int> submsg_indexes;
     MessageLayout layout(message);
     std::vector<const protobuf::FieldDescriptor*> sorted_submsgs =
         SortedSubmessages(message);
diff --git a/upbc/message_layout.h b/upbc/message_layout.h
index a4cb289..c2446a0 100644
--- a/upbc/message_layout.h
+++ b/upbc/message_layout.h
@@ -2,8 +2,8 @@
 #ifndef UPBC_MESSAGE_LAYOUT_H
 #define UPBC_MESSAGE_LAYOUT_H
 
-#include <unordered_map>
 #include "absl/base/macros.h"
+#include "absl/container/flat_hash_map.h"
 #include "google/protobuf/descriptor.h"
 
 namespace upbc {
@@ -70,7 +70,7 @@ class MessageLayout {
   Size Place(SizeAndAlign size_and_align);
 
   template <class K, class V>
-  static V GetMapValue(const std::unordered_map<K, V>& map, K key) {
+  static V GetMapValue(const absl::flat_hash_map<K, V>& map, K key) {
     auto iter = map.find(key);
     if (iter == map.end()) {
       fprintf(stderr, "No value for field.\n");
@@ -92,11 +92,11 @@ class MessageLayout {
   static int64_t FieldLayoutRank(
       const google::protobuf::FieldDescriptor* field);
 
-  std::unordered_map<const google::protobuf::FieldDescriptor*, Size>
+  absl::flat_hash_map<const google::protobuf::FieldDescriptor*, Size>
       field_offsets_;
-  std::unordered_map<const google::protobuf::FieldDescriptor*, int>
+  absl::flat_hash_map<const google::protobuf::FieldDescriptor*, int>
       hasbit_indexes_;
-  std::unordered_map<const google::protobuf::OneofDescriptor*, Size>
+  absl::flat_hash_map<const google::protobuf::OneofDescriptor*, Size>
       oneof_case_offsets_;
   Size maxalign_;
   Size size_;