fix ninja and sync simple examples

novas0x2a · novas0x2a · commit 8a86fdf2705e · 2026-03-07T01:14:36.000-08:00
ninja and make fit roughly into the same category of build system, but
we were only setting up the C build variables for make. This finishes
the ninja implementation to match make (more or less) and then syncs the
simple examples to match. The simple examples that don't already have
compiler integrations (i.e. make and ninja) now use the same wrapper,
which loads data from the configured toolchain instead of calling PATH
binaries.
diff --git a/.bazelci/config.yaml b/.bazelci/config.yaml
@@ -170,8 +170,6 @@ tasks:
       - "-//cmake_synthetic/..."
       # TODO: Fix `error LNK2019: unresolved external symbol hello_func`
       - "-//cmake_hello_world_lib/shared/..."
-      # TODO: Fix `CreateProcess failed: The system cannot find the file specified.`
-      - "-//ninja_simple/..."
       # TODO: The use of Visual Studio generator targets are broken. These should
       # be re-enabled pending a resolution to
       # https://github.com/bazelbuild/continuous-integration/issues/1204
diff --git a/examples/BUILD.bazel b/examples/BUILD.bazel
@@ -1,5 +1,9 @@
 load("@rules_python//python/pip_install:requirements.bzl", "compile_pip_requirements")
 
+exports_files([
+    "cc_wrapper.sh",
+])
+
 test_suite(
     name = "third_party_examples_linux_tests",
     tags = ["manual"],
diff --git a/examples/cc_wrapper.sh b/examples/cc_wrapper.sh
@@ -0,0 +1,92 @@
+#!/usr/bin/env bash
+
+# This wrapper exists to provide a simplified way to wrap the compiler to do
+# the simple examples (make/ninja) that don't have the capability of doing
+# their own compiler setup. This exists _just_ to demonstrate and test
+# functionality for these simple builds, and if you're doing something real,
+# for your sake, use a full cross-platform build system like cmake and _don't_
+# use this script :)
+
+set -euo pipefail
+set -x
+
+die() {
+    echo "$*" >&2
+    exit 42
+}
+
+ensure_absolute() {
+    local path="$1"
+
+    # Tool paths may be provided with surrounding quotes on Windows.
+    path="${path#\"}"
+    path="${path%\"}"
+
+    case "$path" in
+        /*|[A-Za-z]:[\\/]*)
+            # already absolute (maybe with a drive path)
+            echo "$path"
+            ;;
+        *)
+            echo "$EXT_BUILD_ROOT/$path"
+            ;;
+    esac
+}
+
+compile() {
+    if [[ -z "${CXX:-}" ]]; then
+        die "CXX is not set"
+    fi
+
+    local cxx
+    cxx="$(ensure_absolute "$CXX")"
+
+    case "$cxx" in
+        */cl.exe)
+            "$cxx" /c "$1" ${CXXFLAGS:-} "/Fo$2"
+            ;;
+        *)
+            "$cxx" -c "$1" ${CXXFLAGS:-} -o "$2"
+            ;;
+    esac
+}
+
+static_link() {
+    if [[ -z "${AR:-}" ]]; then
+        die "AR is not set"
+    fi
+
+    local ar
+    ar="$(ensure_absolute "$AR")"
+
+    case "$ar" in
+        */lib.exe)
+            "$ar" ${ARFLAGS:-/nologo} "/OUT:$2" "$1"
+            ;;
+        */libtool)
+            # Note that this is darwin libtool, not gnu.
+             "$ar" ${ARFLAGS:-} -static -o "$2" "$1"
+             ;;
+        *)
+            "$ar" ${ARFLAGS:-rcsD} "$2" "$1"
+            ;;
+    esac
+}
+
+if [[ -z "${EXT_BUILD_ROOT:-}" ]]; then
+    die "EXT_BUILD_ROOT is not set"
+fi
+
+if [[ "$#" -ne 3 ]]; then
+    die "Usage: $0 <verb> <input> <output>"
+fi
+
+verb=$1
+input=$2
+output=$3
+
+case "$verb" in
+    compile) compile "$input" "$output" ;;
+    static_link) static_link "$input" "$output" ;;
+    *) die "unknown verb: $verb" ;;
+esac
diff --git a/examples/make_simple/BUILD.bazel b/examples/make_simple/BUILD.bazel
@@ -4,14 +4,14 @@ load("@rules_foreign_cc//foreign_cc:defs.bzl", "make")
 make(
     name = "make_lib",
     build_data = [
-        "//make_simple/code:cxx_wrapper.sh",
+        "//:cc_wrapper.sh",
         "README.md",
     ],
     copts = [
         "-DREQUIRED_DEFINE",
     ],
     env = {
-        "CXX_WRAPPER": "$(execpath //make_simple/code:cxx_wrapper.sh)",
+        "CC_WRAPPER": "$(execpath //:cc_wrapper.sh)",
         "README_DIR": "$$(dirname $(execpath README.md))",
     },
     lib_source = "//make_simple/code:srcs",
diff --git a/examples/make_simple/code/BUILD.bazel b/examples/make_simple/code/BUILD.bazel
@@ -1,5 +1,3 @@
-exports_files(["cxx_wrapper.sh"])
-
 filegroup(
     name = "srcs",
     srcs = [
diff --git a/examples/make_simple/code/Makefile b/examples/make_simple/code/Makefile
@@ -1,19 +1,10 @@
 BUILD_DIR := build-out
 
-UNAME := $(shell uname)
-
-ifneq (,$(findstring NT, $(UNAME)))
-  # If Windows
-  CXXFLAGS := $(CXXFLAGS) /MD
-else
-  CXXFLAGS := $(CXXFLAGS) -fPIC
-endif
-
 default all $(BUILD_DIR)/lib/liba.a: liba.cpp liba.h
 	rm -rf $(BUILD_DIR)/lib
 	mkdir -p $(BUILD_DIR)/lib
-	$(CXX_WRAPPER) $(CXXFLAGS) -o $(BUILD_DIR)/lib/liba.o -c liba.cpp
-	ar rcs $(BUILD_DIR)/lib/liba.a $(BUILD_DIR)/lib/liba.o
+	bash $(CC_WRAPPER) compile liba.cpp $(BUILD_DIR)/lib/liba.o
+	bash $(CC_WRAPPER) static_link $(BUILD_DIR)/lib/liba.o  $(BUILD_DIR)/lib/liba.a
 
 .PHONY: all
 
diff --git a/examples/make_simple/code/cxx_wrapper.sh b/examples/make_simple/code/cxx_wrapper.sh
diff --git a/examples/meson_simple/BUILD.bazel b/examples/meson_simple/BUILD.bazel
@@ -4,17 +4,6 @@ load("@rules_shell//shell:sh_test.bzl", "sh_test")
 
 meson(
     name = "meson_lib",
-    build_data = ["//meson_simple/code:clang_wrapper.sh"],
-    env = select({
-        "@platforms//os:windows": {
-            "CLANG_WRAPPER": "$(execpath //meson_simple/code:clang_wrapper.sh)",
-            "CXX_FLAGS": "/MD",
-        },
-        "//conditions:default": {
-            "CLANG_WRAPPER": "$(execpath //meson_simple/code:clang_wrapper.sh)",
-            "CXX_FLAGS": "-fPIC",
-        },
-    }),
     lib_source = "//meson_simple/code:srcs",
     out_static_libs = ["liba.a"],
 )
diff --git a/examples/meson_simple/code/BUILD.bazel b/examples/meson_simple/code/BUILD.bazel
@@ -1,5 +1,3 @@
-exports_files(["clang_wrapper.sh"])
-
 filegroup(
     name = "srcs",
     srcs = [
diff --git a/examples/meson_simple/code/clang_wrapper.sh b/examples/meson_simple/code/clang_wrapper.sh
diff --git a/examples/ninja_simple/BUILD.bazel b/examples/ninja_simple/BUILD.bazel
@@ -3,17 +3,10 @@ load("@rules_foreign_cc//foreign_cc:defs.bzl", "ninja")
 
 ninja(
     name = "ninja_lib",
-    build_data = ["//ninja_simple/code:clang_wrapper.sh"],
-    env = select({
-        "@platforms//os:windows": {
-            "CLANG_WRAPPER": "$(execpath //ninja_simple/code:clang_wrapper.sh)",
-            "CXX_FLAGS": "/MD",
-        },
-        "//conditions:default": {
-            "CLANG_WRAPPER": "$(execpath //ninja_simple/code:clang_wrapper.sh)",
-            "CXX_FLAGS": "-fPIC",
-        },
-    }),
+    build_data = ["//:cc_wrapper.sh"],
+    env = {
+        "CC_WRAPPER": "$(execpath //:cc_wrapper.sh)",
+    },
     lib_source = "//ninja_simple/code:srcs",
     out_static_libs = ["liba.a"],
     targets = [
@@ -24,6 +17,7 @@ ninja(
 
 cc_test(
     name = "test_lib",
+    size = "small",
     srcs = [
         "test_libb.cpp",
     ],
diff --git a/examples/ninja_simple/README.md b/examples/ninja_simple/README.md
@@ -2,7 +2,7 @@
 
 ## Dependencies
 
-- clang
+- a working c++ toolchain
 - bazel
 
 ## Executing the Example
diff --git a/examples/ninja_simple/code/BUILD.bazel b/examples/ninja_simple/code/BUILD.bazel
@@ -1,5 +1,3 @@
-exports_files(["clang_wrapper.sh"])
-
 filegroup(
     name = "srcs",
     srcs = [
diff --git a/examples/ninja_simple/code/build.ninja b/examples/ninja_simple/code/build.ninja
@@ -6,27 +6,26 @@ ninja_required_version = 1.3
 
 builddir       = rules_foreign_cc_build
 rm             = rm -fr
-cxx            = $$CLANG_WRAPPER
-ar             = ar
 lib            = $builddir/liba.a
+ar_flags       = $$AR_FLAGS
 cxx_flags      = $$CXX_FLAGS
 
 # Rules
 
 rule compile
-  command = $cxx -c $in $cxx_flags -o $out
+  command = bash -c '"$$CC_WRAPPER" compile "$$1" "$$2"' -- "$in" "$out"
   description = Building C file $in
 
 rule ar
-  command = $rm $out && $ar crs $out $in
+  command = bash -c '"$$CC_WRAPPER" static_link "$$1" "$$2"' -- "$in" "$out"
   description = Creating archive $out
 
 rule clean
-  command = $rm $builddir
+  command = rm -fr $builddir
   description = Cleaning directory $builddir
 
 rule install
-  command = mkdir -p $$INSTALLDIR/lib $$INSTALLDIR/include && cp -rpv $builddir/*.a $$INSTALLDIR/lib/ && cp -p liba.h $$INSTALLDIR/include/
+  command = bash -c 'mkdir -p "$$INSTALLDIR/lib" "$$INSTALLDIR/include" && cp -p $lib "$$INSTALLDIR/lib/" && cp -p liba.h "$$INSTALLDIR/include/"'
   description = Installing compiled lib
 
 # Builds
diff --git a/examples/ninja_simple/code/clang_wrapper.sh b/examples/ninja_simple/code/clang_wrapper.sh
diff --git a/foreign_cc/BUILD.bazel b/foreign_cc/BUILD.bazel
@@ -117,8 +117,10 @@ bzl_library(
     srcs = ["ninja.bzl"],
     visibility = ["//visibility:public"],
     deps = [
+        "//foreign_cc/private:cc_toolchain_util",
         "//foreign_cc/private:detect_root",
         "//foreign_cc/private:framework",
+        "//foreign_cc/private:ninja_script",
         "//toolchains/native_tools:tool_access",
         "@rules_cc//cc:bzl_srcs",
         "@rules_cc//cc/common",
diff --git a/foreign_cc/ninja.bzl b/foreign_cc/ninja.bzl
@@ -1,6 +1,12 @@
 """A rule for building projects using the [Ninja](https://ninja-build.org/) build tool"""
 
+load("@bazel_tools//tools/cpp:toolchain_utils.bzl", "find_cpp_toolchain")
 load("@rules_cc//cc:defs.bzl", "CcInfo")
+load(
+    "//foreign_cc/private:cc_toolchain_util.bzl",
+    "get_flags_info",
+    "get_tools_info",
+)
 load(
     "//foreign_cc/private:detect_root.bzl",
     "detect_root",
@@ -13,6 +19,7 @@ load(
     "create_attrs",
     "expand_locations_and_make_variables",
 )
+load("//foreign_cc/private:ninja_script.bzl", "create_ninja_script")
 load("//toolchains/native_tools:tool_access.bzl", "get_ninja_data")
 
 def _ninja_impl(ctx):
@@ -48,11 +55,12 @@ def _create_ninja_script(configureParameters):
     """
     ctx = configureParameters.ctx
     attrs = configureParameters.attrs
-
-    script = []
+    inputs = configureParameters.inputs
 
     root = detect_root(ctx.attr.lib_source)
-    script.append("##symlink_contents_to_dir## $$EXT_BUILD_ROOT$$/{} $$BUILD_TMPDIR$$ False".format(root))
+
+    tools = get_tools_info(ctx)
+    flags = get_flags_info(ctx)
 
     data = ctx.attr.data + ctx.attr.build_data
 
@@ -67,22 +75,28 @@ def _create_ninja_script(configureParameters):
     if ctx.attr.directory:
         directory = ctx.expand_location(ctx.attr.directory, data)
 
+    user_env = expand_locations_and_make_variables(ctx, ctx.attr.env, "env", data)
+
     prefix = "{} ".format(expand_locations_and_make_variables(ctx, attrs.tool_prefix, "tool_prefix", data)) if attrs.tool_prefix else ""
 
-    # Generate commands for all the targets, ensuring there's
-    # always at least 1 call to the default target.
-    for target in ctx.attr.targets or [""]:
-        # Note that even though directory is always passed, the
-        # following arguments can take precedence.
-        script.append("{prefix}{ninja} -C {dir} {args} {target}".format(
-            prefix = prefix,
-            ninja = attrs.ninja_path,
-            dir = directory,
-            args = args,
-            target = target,
-        ))
-
-    return script
+    cc_toolchain = find_cpp_toolchain(ctx)
+    is_msvc = cc_toolchain.compiler == "msvc-cl"
+
+    return create_ninja_script(
+        workspace_name = ctx.workspace_name,
+        tools = tools,
+        flags = flags,
+        root = root,
+        deps = ctx.attr.deps,
+        inputs = inputs,
+        env_vars = user_env,
+        ninja_prefix = prefix,
+        ninja_path = attrs.ninja_path,
+        ninja_targets = ctx.attr.targets or [""],
+        ninja_args = args,
+        ninja_directory = directory,
+        is_msvc = is_msvc,
+    )
 
 def _attrs():
     """Modifies the common set of attributes used by rules_foreign_cc and sets Ninja specific attrs
diff --git a/foreign_cc/private/BUILD.bazel b/foreign_cc/private/BUILD.bazel
diff --git a/foreign_cc/private/ninja_script.bzl b/foreign_cc/private/ninja_script.bzl

Original file line number	Diff line number	Diff line change
`@@ -1,5 +1,3 @@`
`1`		`-exports_files(["cxx_wrapper.sh"])`
`2`		`-`
`3`	`1`	`filegroup(`
`4`	`2`	`name = "srcs",`
`5`	`3`	`srcs = [`
Original file line number	Diff line number	Diff line change
`@@ -1,5 +1,3 @@`
`1`		`-exports_files(["clang_wrapper.sh"])`
`2`		`-`
`3`	`1`	`filegroup(`
`4`	`2`	`name = "srcs",`
`5`	`3`	`srcs = [`