Support multiple execution platforms with system_cxx_toolchain

examples/visual_studio/.buckconfig

@@ -11,7 +11,14 @@ fbsource = none
 buck = none
 
 [parser]
-target_platform_detector_spec = target:root//...->toolchains//:default
+target_platform_detector_spec = target:root//...->root//buck2_utils/platforms:windows_debug
 
 [build]
-execution_platforms = prelude//platforms:default
+execution_platforms = root//buck2_utils/platforms:default
+
+[buck2_re_client]
+action_cache_address = grpc://localhost:8980
+engine_address = grpc://localhost:8980
+cas_address = grpc://localhost:8980
+tls = false
+instance_name = fuse

examples/visual_studio/buck2_utils/create_compile_commands.bxl

@@ -85,7 +85,7 @@ def gen_compilation_database_impl(ctx):
 
         if not "write" in actions_by_category:
             continue
-        if not "cxx_compile" in actions_by_category:
+        if not "cxx_compile" in actions_by_category and not "c_compile" in actions_by_category:
             continue
 
         argsfiles = {}
@@ -111,7 +111,7 @@ def gen_compilation_database_impl(ctx):
                 argsfiles[identifier] = arguments
 
         # Now walk each compilation action and generate a compilation database entry for it.
-        for action in actions_by_category["cxx_compile"]:
+        for action in actions_by_category.get("cxx_compile", []) + actions_by_category.get("c_compile", []):
             entry = create_compilation_database_entry(ctx.cli_args.directory, buildfile_folder, argsfiles, action)
             is_pic = entry["file"].endswith(" (pic)")
             file_name = entry["file"].removesuffix(" (pic)")

examples/visual_studio/buck2_utils/install.ps1

@@ -29,7 +29,8 @@ begin
 			[parameter(Mandatory=$true)] [String] $SourcePath,
 			[parameter(Mandatory=$true)] [String] $TargetPath
 		)
-		Copy-Item $SourcePath -Destination $TargetPath
+		New-Item -ItemType File -Path $TargetPath -Force | Out-Null
+		Copy-Item $SourcePath -Destination $TargetPath | Out-Null
 	}
 }
 process

examples/visual_studio/buck2_utils/platforms/BUCK

@@ -0,0 +1,38 @@
+load(":defs.bzl", "execution_platforms")
+
+execution_platforms(
+    name = "default",
+    visibility = ["PUBLIC"],
+)
+
+platform(
+    name = "windows_debug",
+    constraint_values = [
+        "config//os/constraints:windows",
+        "root//buck2_utils/configuration:debug",
+    ],
+)
+
+platform(
+    name = "windows_release",
+    constraint_values = [
+        "config//os/constraints:windows",
+        "root//buck2_utils/configuration:release",
+    ],
+)
+
+platform(
+    name = "linux_debug",
+    constraint_values = [
+        "config//os/constraints:linux",
+        "root//buck2_utils/configuration:debug",
+    ],
+)
+
+platform(
+    name = "linux_release",
+    constraint_values = [
+        "config//os/constraints:linux",
+        "root//buck2_utils/configuration:release",
+    ],
+)

examples/visual_studio/buck2_utils/platforms/defs.bzl

@@ -0,0 +1,61 @@
+def is_remote_enabled() -> bool:
+    re_enabled = read_config("buck2_re_client", "enabled", "false")
+    return re_enabled == "true"
+
+def _execution_platforms_impl(ctx: AnalysisContext) -> list[Provider]:
+    is_re_enabled = is_remote_enabled()
+
+    name = ctx.label.raw_target()
+
+    constraints_windows = dict()
+    constraints_windows.update(ctx.attrs.os_configuration_windows[ConfigurationInfo].constraints)
+    constraints_linux = dict()
+    constraints_linux.update(ctx.attrs.os_configuration_linux[ConfigurationInfo].constraints)
+
+    platforms_details = [
+        ("windows", host_info().os.is_windows, constraints_windows),
+        ("linux", host_info().os.is_linux, constraints_linux),
+    ]
+
+    platforms = []
+    for platform_name, is_local_enabled, constraints in platforms_details:
+        if is_re_enabled or is_local_enabled:
+            platforms.append(
+                ExecutionPlatformInfo(
+                    label = name,
+                    configuration = ConfigurationInfo(
+                        constraints = constraints,
+                        values = {},
+                    ),
+                    executor_config = CommandExecutorConfig(
+                        local_enabled = is_local_enabled,
+                        remote_enabled = is_re_enabled,
+                        use_limited_hybrid = True,
+                        remote_execution_properties = {
+                            "OSFamily": platform_name,
+                            "container-image": "docker://" + platform_name + "_build",
+                        },
+                        remote_execution_use_case = "buck2-default",
+                        use_windows_path_separators = platform_name == "windows",
+                    ),
+                )
+            )
+
+    return [
+        DefaultInfo(),
+        ExecutionPlatformRegistrationInfo(platforms = platforms),
+    ]
+
+execution_platforms = rule(
+    impl = _execution_platforms_impl,
+    attrs = {
+        "os_configuration_windows": attrs.dep(
+            providers = [ConfigurationInfo],
+            default = "config//os:windows",
+        ),
+        "os_configuration_linux": attrs.dep(
+            providers = [ConfigurationInfo],
+            default = "config//os:linux",
+        ),
+    },
+)

examples/visual_studio/library.hpp

@@ -13,6 +13,8 @@
 #else
 #define DLL_API __declspec(dllimport)
 #endif
+#else
+#define DLL_API
 #endif
 
 #ifdef __cplusplus

examples/visual_studio/toolchains/BUCK

@@ -1,8 +1,29 @@
 load("@prelude//toolchains:cxx.bzl", "system_cxx_toolchain")
+load("@prelude//toolchains/cxx/clang:tools.bzl", "path_clang_tools")
+load("@prelude//toolchains/msvc:tools.bzl", "find_msvc_tools")
 load("@prelude//toolchains:python.bzl", "system_python_bootstrap_toolchain")
+load("@root//buck2_utils/platforms:defs.bzl", "is_remote_enabled")
+
+find_msvc_tools(
+    name = "msvc_tools",
+    use_path_compilers = is_remote_enabled(),
+    use_path_linkers = is_remote_enabled() and not host_info().os.is_windows,
+    target_compatible_with = ["config//os:windows"],
+    visibility = ["PUBLIC"],
+)
+
+path_clang_tools(
+    name = "clang_tools",
+    target_compatible_with = ["config//os:linux"],
+    visibility = ["PUBLIC"],
+)
 
 system_cxx_toolchain(
     name = "cxx",
+    toolchain_info = select({
+        "config//os:windows": ":msvc_tools",
+        "config//os:linux": ":clang_tools",
+    }),
     #The flags in the below attributes' Windows config are copied from Visual Studio's project "Console App", with some changes listed in each attribute
     c_flags = select({
         "config//os:linux": [],
@@ -111,11 +132,3 @@ system_python_bootstrap_toolchain(
     name = "python_bootstrap",
     visibility = ["PUBLIC"],
 )
-
-configuration = read_config("cxx", "configuration", "debug")
-
-platform(
-    name = "default",
-    constraint_values = ["root//buck2_utils/configuration:release"] if configuration == "release" else ["root//buck2_utils/configuration:debug"],
-    deps = ["prelude//platforms:default"],
-)