Cleanup the new dependencies and our tooling setup. (#943)

I didn't fully configure the new dependencies correctly or fully get
them working with our tooling rigging for compilation databases.

- I needed to fix the sha256 of the benchmark. I pasted the wrong
  one, but didn't test it effectively.

- Didn't successfully enable the use of Abseil from GoogleTest
  (including nice things like its symbolization, etc). Doing this is
  a bit awkward as it needs to go into our `.bazelrc`, but it works.

- Didn't add libraries other that GoogleTest to the compile flags.

- Didn't teach the compilation database creation step to cause these
  external repositories to be linked in and populated nicely.

All of these are fixed. As I was making changes to the Python script
here, I've added a test to at least type check it and fixed the type
errors reported.

.bazelrc

@@ -45,6 +45,9 @@ build --force_pic
 # crashes. Optimized builds already avoid using debug information by default.
 build --strip=never
 
+# Enable Abseil for GoogleTest.
+build --define=absl=1
+
 # Configuration for enabling Address Sanitizer. Note that this is enabled by
 # default for fastbuild. The config is provided to enable ASan even in
 # optimized or other build configurations.

WORKSPACE

@@ -123,7 +123,7 @@ benchmark_version = "0baacde3618ca617da95375e0af13ce1baadea47"
 
 http_archive(
     name = "com_github_google_benchmark",
-    sha256 = "19949c33e795197dbb8610672c18bff447dc31faef3257665d69d1bf0884d67b",
+    sha256 = "62e2f2e6d8a744d67e4bbc212fcfd06647080de4253c97ad5c6749e09faf2cb0",
     strip_prefix = "benchmark-%s" % benchmark_version,
     urls = ["https://github.com/google/benchmark/archive/%s.zip" % benchmark_version],
 )

compile_flags.txt

@@ -34,7 +34,7 @@
 -DLLVM_DEFAULT_TARGET_TRIPLE="x86_64-unknown-linux-gnu"
 -DLLVM_ENABLE_TERMINFO=1
 -DLLVM_ENABLE_ZLIB=1
--DGTEST_HAS_RTTI=0
+-DGTEST_HAS_ABSL=1
 -D__STDC_LIMIT_MACROS
 -D__STDC_CONSTANT_MACROS
 -iquote
@@ -58,9 +58,22 @@ bazel-execroot/external/llvm_zlib
 -iquote
 bazel-bin/external/llvm_zlib
 -iquote
+bazel-execroot/external/com_github_google_benchmark
+-iquote
+bazel-bin/external/com_github_google_benchmark
+-iquote
+bazel-execroot/external/com_google_absl
+-iquote
+bazel-bin/external/com_google_absl
+-iquote
+bazel-execroot/external/com_google_googletest
+-iquote
+bazel-bin/external/com_google_googletest
+-iquote
 bazel-execroot/external/bazel_tools
 -iquote
 bazel-bin/external/bazel_tools
+-Ibazel-bin/external/com_github_google_benchmark/_virtual_includes/benchmark
 -isystem
 bazel-execroot/external/llvm-project/llvm/include
 -isystem

scripts/BUILD

@@ -0,0 +1,18 @@
+# Part of the Carbon Language project, under the Apache License v2.0 with LLVM
+# Exceptions. See /LICENSE for license information.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+load("@mypy_integration//:mypy.bzl", "mypy_test")
+
+# Note that this Python script is intended to be run directly, and not through
+# Bazel. We have a rule for it so we can type check it.
+py_binary(
+    name = "create_compdb",
+    srcs = ["create_compdb.py"],
+)
+
+mypy_test(
+    name = "create_compdb_mypy_test",
+    include_imports = True,
+    deps = [":create_compdb"],
+)

scripts/create_compdb.py

@@ -129,10 +129,25 @@ print("Found %d generated files..." % (len(generated_file_labels),))
 print("Building the generated files so that tools can find them...")
 subprocess.run([bazel, "build", "--keep_going"] + generated_file_labels)
 
+# Also build some specific targets that depend on external packages so those are
+# fetched and linked into the Bazel execution root. We try to use cheap files
+# where possible, but in some cases need to create a virtual include directory.
+subprocess.run(
+    [
+        bazel,
+        "build",
+        "--keep_going",
+        "@llvm-project//llvm:LICENSE.TXT",
+        "@com_google_absl//:LICENSE",
+        "@com_google_googletest//:LICENSE",
+        "@com_github_google_benchmark//:benchmark",
+    ]
+)
+
 
 # Manually translate the label to a user friendly path into the Bazel output
 # symlinks.
-def _label_to_path(s):
+def _label_to_path(s: str) -> Path:
     # Map external repositories to their part of the output tree.
     s = re.sub(r"^@([^/]+)//", r"bazel-bin/external/\1/", s)
     # Map this repository to the root of the output tree.