Update the Bazel build files (#4190)

* Add license function to Bazel build files.

* Patch up the P4Tools build files.

* Update Bazelisk version.

* Remove Bazel version restriction for the indirect build.

* Fix up IR Extension for example project.

* Restore removed comment.

Author: fruffy-g

.bazelignore

@@ -2,3 +2,4 @@
 control-plane/p4runtime
 test/frameworks/gtest
 bazel/example
+build

.github/workflows/ci-bazel.yml

@@ -34,7 +34,7 @@ jobs:
 
     - name: Install bazelisk
       run: |
-        curl -LO "https://github.com/bazelbuild/bazelisk/releases/download/v1.7.1/$BAZEL"
+        curl -LO "https://github.com/bazelbuild/bazelisk/releases/download/v1.18.0/$BAZEL"
         chmod +x $BAZEL
         sudo mv $BAZEL /usr/local/bin/bazel
 
@@ -66,7 +66,7 @@ jobs:
 
     - name: Install bazelisk
       run: |
-        curl -LO "https://github.com/bazelbuild/bazelisk/releases/download/v1.4.0/$BAZEL"
+        curl -LO "https://github.com/bazelbuild/bazelisk/releases/download/v1.18.0/$BAZEL"
         chmod +x $BAZEL
         sudo mv $BAZEL /usr/local/bin/bazel
 

BUILD.bazel

@@ -1,9 +1,19 @@
+load("@rules_license//rules:license.bzl", "license")
 load("//:bazel/flex.bzl", "genlex")
 load("//:bazel/bison.bzl", "genyacc")
 
 package(
+    default_applicable_licenses = ["//:license"],
     default_visibility = ["//visibility:public"],
-    licenses = ["notice"],
+)
+
+license(
+    name = "license",
+    package_name = "com_github_p4lang_p4c",
+    license_kinds = [
+        "@rules_license//licenses/spdx:Apache-2.0",
+    ],
+    license_text = "LICENSE",
 )
 
 filegroup(
@@ -146,10 +156,10 @@ filegroup(
         "frontends/p4-14/ir-v1.def",
         "backends/bmv2/bmv2.def",
         "backends/dpdk/dpdk.def",
-        "//backends/p4tools:p4tools.def",
+        "//backends/p4tools:ir_extension",
         # p4c extensions may set this target to a `filegroup` containing
         # additional .def files.
-        "@com_github_p4lang_p4c_extension//:ir_extensions",
+        "@com_github_p4lang_p4c_extension//:ir_extension",
     ],
 )
 

backends/p4tools/BUILD.bazel

@@ -1,15 +1,20 @@
 # The BUILD file for p4testgen, inspired by the tool's cmake build rules.
 
-exports_files(["p4tools.def"])
+load("@bazel_skylib//rules:build_test.bzl", "build_test")
 
 package(
+    default_applicable_licenses = ["//:license"],
     licenses = ["notice"],
 )
 
 # Extend the list with the name of the desired targets (in "modules/testgen/targets/).
-TESTGEN_TARGETS = [
-    "bmv2",
-]
+TESTGEN_TARGETS = ["bmv2"]
+
+filegroup(
+    name = "ir_extension",
+    srcs = ["p4tools.def"],
+    visibility = ["//visibility:public"],  # So p4c can compile these.
+)
 
 genrule(
     name = "version",
@@ -72,10 +77,14 @@ genrule(
 filegroup(
     name = "testgen_targets_src",
     srcs =
-        glob(["modules/testgen/targets/%s/**/*.h" % target for target in TESTGEN_TARGETS],
-             exclude = ["modules/testgen/targets/%s/test/**" % target for target in TESTGEN_TARGETS]) +
-        glob(["modules/testgen/targets/%s/**/*.cpp" % target for target in TESTGEN_TARGETS],
-             exclude = ["modules/testgen/targets/%s/test/**" % target for target in TESTGEN_TARGETS]),
+        glob(
+            ["modules/testgen/targets/%s/**/*.h" % target for target in TESTGEN_TARGETS],
+            exclude = ["modules/testgen/targets/%s/test/**" % target for target in TESTGEN_TARGETS],
+        ) +
+        glob(
+            ["modules/testgen/targets/%s/**/*.cpp" % target for target in TESTGEN_TARGETS],
+            exclude = ["modules/testgen/targets/%s/test/**" % target for target in TESTGEN_TARGETS],
+        ),
 )
 
 cc_library(
@@ -133,3 +142,10 @@ cc_binary(
         "//:lib",
     ],
 )
+
+build_test(
+    name = "p4testgen_build_test",
+    targets = [
+        ":p4testgen",
+    ],
+)

bazel/example/.bazelversion

@@ -1 +0,0 @@
-5.4.0

bazel/example/BUILD.bazel

@@ -1,5 +1,5 @@
 filegroup(
-  name = "ir_extensions",
+  name = "ir_extension",
   srcs = glob(["*.def"]),
   visibility = ["//visibility:public"],  # So p4c can compile these.
 )

bazel/example/WORKSPACE.bazel

@@ -6,7 +6,7 @@ local_repository(
   path = "../..",
   # This part is optional: only needed for custom backends with IR extensions.
   repo_mapping = {
-    # Tells p4c where to look for `:ir_extensions` target: in this project.
+    # Tells p4c where to look for `:ir_extension` target: in this project.
     "@com_github_p4lang_p4c_extension" : "@example_p4_project",
   },
 )

bazel/p4c_deps.bzl

@@ -6,7 +6,7 @@ load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
 def p4c_deps():
     """Loads dependencies need to compile p4c."""
     # Third party projects can define the target
-    # @com_github_p4lang_p4c_extension:ir_extensions with a `filegroup`
+    # @com_github_p4lang_p4c_extension:ir_extension with a `filegroup`
     # containing their custom .def files.
     if not native.existing_rule("com_github_p4lang_p4c_extension"):
         # By default, no IR extensions.
@@ -15,7 +15,7 @@ def p4c_deps():
             path = ".",
             build_file_content = """
 filegroup(
-    name = "ir_extensions",
+    name = "ir_extension",
     srcs = [],
     visibility = ["//visibility:public"],
 )