feat: add bazel support

Author: GuillaumeLagrange

.bazelrc

@@ -0,0 +1 @@
+build --//core:codspeed_mode=instrumentation

.bazelversion

@@ -0,0 +1 @@
+7.6.1

.github/workflows/ci.yml

@@ -39,6 +39,26 @@ jobs:
       with:
         name: test_results
         path: ${{runner.workspace}}/core/build-tests/test/test-results/**/*.json
+
+  bazel-build:
+    name: Build Bazel benchmarks
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up Bazel
+        uses: bazel-contrib/setup-bazel@0.14.0
+        with:
+          # Avoid downloading Bazel every time.
+          bazelisk-cache: true
+          # Store build cache per workflow.
+          disk-cache: ${{ github.workflow }}
+          # Share repository cache between workflows.
+          repository-cache: true
+
+      - name: Build and run benchmarks
+        run: |
+          bazel run //examples/google_benchmar:my_benchmark
   
   instrumentation:
     runs-on: ubuntu-latest

.gitignore

@@ -7,3 +7,6 @@ build/
 
 # Clangd cache
 .cache/
+
+# Bazel output
+/bazel-*

MODULE.bazel

@@ -0,0 +1 @@
+bazel_dep(name = "rules_cc", version = "0.0.17")

MODULE.bazel.lock

@@ -0,0 +1,41 @@
+load("@bazel_skylib//rules:common_settings.bzl", "string_flag")
+load("@rules_cc//cc:defs.bzl", "cc_library")
+
+CODSPEED_VERSION = "1.0.0"
+
+# Define the codspeed library
+cc_library(
+    name = "codspeed",
+    srcs = glob(["src/**/*.cpp"] + ["src/**/*.h"] + ["src/**/*.hpp"]),
+    hdrs = ["include/codspeed.h"],
+    includes = ["include"],
+    defines = [
+        "CODSPEED_VERSION=\\\"{}\\\"".format(CODSPEED_VERSION),
+    ] + select({
+        ":instrumentation_mode": ["CODSPEED_ENABLED", "CODSPEED_INSTRUMENTATION"],
+        ":walltime_mode": ["CODSPEED_ENABLED", "CODSPEED_WALLTIME"],
+        "//conditions:default": [],
+    }),
+    visibility = ["//visibility:public"],
+)
+
+# Codspeed mode
+string_flag(
+    name = "codspeed_mode",
+    build_setting_default = "off",
+    values = [
+        "off",
+        "instrumentation",
+        "walltime",
+    ],
+)
+
+config_setting(
+    name = "instrumentation_mode",
+    flag_values = {":codspeed_mode": "instrumentation"},
+)
+
+config_setting(
+    name = "walltime_mode",
+    flag_values = {":codspeed_mode": "walltime"},
+)

core/BUILD

@@ -12,7 +12,13 @@ set(CMAKE_CXX_STANDARD_REQUIRED True)
 include_directories(include)
 
 # Add the library
-add_library(codspeed src/codspeed.cpp src/walltime.cpp src/uri.cpp)
+add_library(
+    codspeed
+    src/codspeed.cpp
+    src/walltime.cpp
+    src/uri.cpp
+    src/workspace.cpp
+)
 
 # Version
 add_compile_definitions(CODSPEED_VERSION="${CODSPEED_VERSION}")
@@ -31,7 +37,7 @@ endif()
 
 execute_process(
     COMMAND git rev-parse --show-toplevel
-    OUTPUT_VARIABLE GIT_ROOT_DIR
+    OUTPUT_VARIABLE CODSPEED_ROOT_DIR
     OUTPUT_STRIP_TRAILING_WHITESPACE
     RESULT_VARIABLE GIT_COMMAND_RESULT
 )
@@ -44,13 +50,14 @@ if(NOT GIT_COMMAND_RESULT EQUAL 0)
         Continuing, but codspeed features will not be useable"
     )
     # Default to user's cmake source directory
-    set(GIT_ROOT_DIR ${CMAKE_SOURCE_DIR})
+    set(CODSPEED_ROOT_DIR ${CMAKE_SOURCE_DIR})
 endif()
 
 target_compile_definitions(
     codspeed
-    INTERFACE -DCODSPEED_GIT_ROOT_DIR="${GIT_ROOT_DIR}"
+    PRIVATE -DCODSPEED_ROOT_DIR="${CODSPEED_ROOT_DIR}"
 )
+message(STATUS "Using codspeed root directory: ${CODSPEED_ROOT_DIR}")
 
 set(CODSPEED_MODE_ALLOWED_VALUES "OFF" "instrumentation" "walltime")
 set(CODSPEED_MODE "OFF" CACHE STRING "Build mode for Codspeed")

core/CMakeLists.txt

@@ -46,6 +46,10 @@ void generate_codspeed_walltime_report(
 std::string extract_lambda_namespace(const std::string &pretty_func);
 std::string sanitize_bench_args(std::string &text);
 
+// Gets path relative to workspace root, expected to be called with __FILE__ as
+// an argument
+std::string get_path_relative_to_workspace(const std::string &path);
+
 } // namespace codspeed
 
 #endif // CODSPEED_H

core/include/codspeed.h

@@ -0,0 +1,25 @@
+// Implementation
+#include "codspeed.h"
+#include <cstdlib>
+#include <filesystem>
+
+namespace codspeed {
+
+std::string get_path_relative_to_workspace(const std::string &path) {
+  // 1. Check for bazel usage, through the BUILD_WORKSPACE_DIRECTORY env var
+  // If so, __FILE__ will already be relative to the bazel workspace root
+  if (std::getenv("BUILD_WORKSPACE_DIRECTORY") != NULL) {
+    return path;
+  }
+
+  // 2. If defined, use the specificed value directly
+#ifdef CODSPEED_ROOT_DIR
+  return std::filesystem::relative(path, CODSPEED_ROOT_DIR).string();
+#endif
+
+  // 3. Fallback to bath relative to PWD
+  return std::filesystem::relative(path, std::filesystem::current_path())
+      .string();
+}
+
+} // namespace codspeed

core/src/workspace.cpp

@@ -0,0 +1,7 @@
+cc_binary(
+    name = "my_benchmark",
+    srcs = glob(["*.cpp", "*.hpp"]),
+    deps = [
+        "//google_benchmark:benchmark",
+    ],
+)

examples/google_benchmark/BUILD.bazel

@@ -20,8 +20,11 @@
         # Common build inputs for both shells
         commonBuildInputs = with pkgs; [
           gcc
-          cmake
           pkg-config
+
+          # Build systems
+          cmake
+          bazelisk
         ];
 
       in

flake.nix

@@ -77,7 +77,7 @@ cc_library(
         "_LARGEFILE_SOURCE",
     ],
     visibility = ["//visibility:public"],
-    deps = select({
+    deps = ["//core:codspeed"] + select({
         ":perfcounters": ["@libpfm"],
         "//conditions:default": [],
     }),

google_benchmark/BUILD.bazel

@@ -1444,7 +1444,7 @@ class Fixture : public internal::Benchmark {
 #include <filesystem>
 
 #define CUR_FILE \
-  std::filesystem::relative(__FILE__, CODSPEED_GIT_ROOT_DIR).string() + "::"
+  codspeed::get_path_relative_to_workspace(__FILE__) + "::"
 #define NAMESPACE \
   (([]() { return codspeed::extract_lambda_namespace(__PRETTY_FUNCTION__); })())
 #define STATIC_NAMESPACE_STRING(name) static std::string name = NAMESPACE;