Add support for aws-crt-swift and complex C dependencies

codeman9 · codeman9 · commit 70627a32fedc · 2025-11-03T08:30:11.000-08:00
- Add umbrella directory modulemap generation to match SPM behavior
- Add framework detection: scan C source files for framework imports and auto-link
- Add default include/ path handling when publicHeadersPath is not specified
- Add header collection from excluded directories (SPM excludes only affect compilation)
- Add aws_crt_example demonstrating aws-crt-swift building successfully

Fixes enable building Swift packages with complex C dependencies that have:
- Inline implementation files (.inl) that should be conditionally included
- Default public header paths (include/)
- Excluded directories containing needed headers
- System framework dependencies not declared in Package.swift

The umbrella directory approach prevents atomics redefinition errors by only
processing headers when explicitly included, rather than importing all headers
upfront when listed individually in the modulemap.
diff --git a/examples/aws_crt_example/.bazelrc b/examples/aws_crt_example/.bazelrc
@@ -0,0 +1,4 @@
+build --enable_bzlmod
+build --lockfile_mode=update
+build --macos_minimum_os=15.0
+build --host_macos_minimum_os=15.0
diff --git a/examples/aws_crt_example/BUILD.bazel b/examples/aws_crt_example/BUILD.bazel
@@ -0,0 +1,9 @@
+load("@build_bazel_rules_swift//swift:swift_test.bzl", "swift_test")
+
+swift_test(
+    name = "AwsCrtTests",
+    srcs = ["Tests/AwsCrtTests/AwsCrtTests.swift"],
+    deps = [
+        "@swiftpkg_aws_crt_swift//:AwsCommonRuntimeKit",
+    ],
+)
diff --git a/examples/aws_crt_example/MODULE.bazel b/examples/aws_crt_example/MODULE.bazel
@@ -0,0 +1,36 @@
+module(name = "aws_crt_example")
+
+bazel_dep(name = "rules_swift_package_manager", version = "")
+local_path_override(
+    module_name = "rules_swift_package_manager",
+    path = "../..",
+)
+
+bazel_dep(name = "apple_support", version = "1.24.2")
+bazel_dep(name = "rules_swift", version = "3.1.2", repo_name = "build_bazel_rules_swift")
+bazel_dep(name = "rules_apple", version = "4.2.0", repo_name = "build_bazel_rules_apple")
+
+apple_cc_configure = use_extension(
+    "@apple_support//crosstool:setup.bzl",
+    "apple_cc_configure_extension",
+)
+use_repo(apple_cc_configure, "local_config_apple_cc")
+
+swift_deps = use_extension(
+    "@rules_swift_package_manager//:extensions.bzl",
+    "swift_deps",
+)
+swift_deps.from_package(
+    resolved = "//:Package.resolved",
+    swift = "//:Package.swift",
+)
+swift_deps.configure_package(
+    name = "aws-crt-swift",
+    init_submodules = True,
+    recursive_init_submodules = True,
+)
+use_repo(
+    swift_deps,
+    "swift_package",
+    "swiftpkg_aws_crt_swift",
+)
diff --git a/examples/aws_crt_example/Package.resolved b/examples/aws_crt_example/Package.resolved
diff --git a/examples/aws_crt_example/Package.swift b/examples/aws_crt_example/Package.swift
@@ -0,0 +1,10 @@
+// swift-tools-version: 5.9
+
+import PackageDescription
+
+let package = Package(
+    name: "AwsCrtExample",
+    dependencies: [
+        .package(url: "https://github.com/awslabs/aws-crt-swift.git", from: "0.54.0"),
+    ]
+)
diff --git a/examples/aws_crt_example/README.md b/examples/aws_crt_example/README.md
@@ -0,0 +1,3 @@
+# AWS CRT Swift Example
+
+This example demonstrates using [aws-crt-swift](https://github.com/awslabs/aws-crt-swift) with Bazel.
diff --git a/examples/aws_crt_example/Tests/AwsCrtTests/AwsCrtTests.swift b/examples/aws_crt_example/Tests/AwsCrtTests/AwsCrtTests.swift
@@ -0,0 +1,10 @@
+import XCTest
+import AwsCommonRuntimeKit
+
+final class AwsCrtTests: XCTestCase {
+    func testCrtTypes() throws {
+        // Test that we can use types from AwsCommonRuntimeKit
+        let logLevel = LogLevel.info
+        XCTAssertEqual(logLevel, LogLevel.info)
+    }
+}
diff --git a/examples/aws_crt_example/WORKSPACE b/examples/aws_crt_example/WORKSPACE
@@ -0,0 +1 @@
+# Intentionally blank. Using bzlmod.
diff --git a/examples/aws_crt_example/WORKSPACE.bzlmod b/examples/aws_crt_example/WORKSPACE.bzlmod
@@ -0,0 +1 @@
+# Intentionally blank. The content for this workspace is generated by bzlmod.
diff --git a/examples/aws_crt_example/do_test b/examples/aws_crt_example/do_test
@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+bazel test //...
diff --git a/swiftpkg/internal/generate_modulemap.bzl b/swiftpkg/internal/generate_modulemap.bzl
@@ -38,12 +38,32 @@ def _generate_modulemap_impl(ctx):
     if len(hdrs) == 0:
         fail("No header files were provided.")
 
+    # Use umbrella directory if all headers share a common root
+    umbrella_dir = None
+    if len(hdrs) > 0:
+        # Find the longest common directory prefix
+        dirs = [h.dirname for h in hdrs]
+        if len(dirs) > 0:
+            common_parts = dirs[0].split("/")
+            for d in dirs[1:]:
+                d_parts = d.split("/")
+                new_common = []
+                for i in range(min(len(common_parts), len(d_parts))):
+                    if common_parts[i] == d_parts[i]:
+                        new_common.append(common_parts[i])
+                    else:
+                        break
+                common_parts = new_common
+            if len(common_parts) > 0:
+                umbrella_dir = "/".join(common_parts)
+
     write_module_map(
         actions = ctx.actions,
         module_map_file = modulemap_file,
         module_name = module_name,
         dependent_module_names = uses,
-        public_headers = hdrs,
+        umbrella_directory = umbrella_dir,
+        public_headers = hdrs if not umbrella_dir else [],
     )
     provider_hdr = [modulemap_file]
 
diff --git a/swiftpkg/internal/module_maps.bzl b/swiftpkg/internal/module_maps.bzl
@@ -32,6 +32,7 @@ def write_module_map(
         private_headers = [],
         private_textual_headers = [],
         umbrella_header = None,
+        umbrella_directory = None,
         workspace_relative = False):
     """Writes the content of the module map to a file.
 
@@ -60,6 +61,8 @@ def write_module_map(
         umbrella_header: A `File` representing an umbrella header that, if
             present, will be written into the module map instead of the list of
             headers in the compilation context.
+        umbrella_directory: A path string representing an umbrella directory that, if
+            present, will be written into the module map instead of individual headers.
         workspace_relative: A Boolean value indicating whether the header paths
             written in the module map file should be relative to the workspace
             or relative to the module map file.
@@ -105,6 +108,10 @@ def write_module_map(
 
     if umbrella_header:
         _add_headers(headers = [umbrella_header], kind = "umbrella header")
+    elif umbrella_directory:
+        # Umbrella directory must be absolute path
+        abs_umbrella = back_to_root_path + umbrella_directory if back_to_root_path else umbrella_directory
+        content.add(abs_umbrella, format = '    umbrella "%s"')
     else:
         _add_headers(headers = public_headers, kind = "header")
         _add_headers(headers = private_headers, kind = "private header")
diff --git a/swiftpkg/internal/pkginfos.bzl b/swiftpkg/internal/pkginfos.bzl
@@ -11,6 +11,7 @@ load(
     "//config_settings/spm/platform:platforms.bzl",
     spm_platforms = "platforms",
 )
+load(":apple_builtin.bzl", "apple_builtin")
 load(":clang_files.bzl", "clang_files")
 load(":objc_files.bzl", "objc_files")
 load(":pkginfo_dependencies.bzl", "pkginfo_dependencies")
@@ -1173,6 +1174,38 @@ def _new_swift_src_info(
 
 # MARK: - Clang Source Info
 
+def _detect_frameworks_from_sources(repository_ctx, srcs):
+    """Detect Apple frameworks from #include <Framework/Header.h> patterns in C source files."""
+    frameworks_set = sets.make()
+    
+    for src in srcs:
+        # Only scan C/C++/ObjC source and header files
+        if not (src.endswith(".c") or src.endswith(".cc") or src.endswith(".cpp") or 
+                src.endswith(".m") or src.endswith(".mm") or src.endswith(".h") or 
+                src.endswith(".hpp")):
+            continue
+        
+        # Read the file and look for framework includes
+        content = repository_ctx.read(src)
+        lines = content.split("\n")
+        for line in lines:
+            line = line.strip()
+            # Look for #include <Framework/Header.h> or #import <Framework/Header.h>
+            if line.startswith("#include") or line.startswith("#import"):
+                # Extract the include path
+                if "<" in line and ">" in line:
+                    start = line.index("<") + 1
+                    end = line.index(">")
+                    include_path = line[start:end]
+                    # Check if it's a framework include (has a slash)
+                    if "/" in include_path:
+                        framework = include_path.split("/")[0]
+                        # Check if it's a known Apple framework
+                        if sets.contains(apple_builtin.frameworks.all, framework):
+                            sets.insert(frameworks_set, framework)
+    
+    return sorted(sets.to_list(frameworks_set))
+
 def _new_clang_src_info_from_sources(
         repository_ctx,
         pkg_path,
@@ -1188,6 +1221,20 @@ def _new_clang_src_info_from_sources(
         paths.join(pkg_path, target_path),
     )
 
+    # If no explicit public headers path is specified, default to "include"
+    # if it exists. This matches Swift Package Manager's behavior for C targets.
+    # Also remove any exclude patterns that would exclude the include directory,
+    # since SPM doesn't exclude public headers even if they're in the exclude list.
+    if public_hdrs_path == None:
+        default_include_path = paths.normalize(paths.join(abs_target_path, "include"))
+        if repository_files.is_directory(repository_ctx, default_include_path):
+            public_hdrs_path = "include"
+            # Remove any exclude paths that start with "include/"
+            exclude_paths = [
+                ep for ep in exclude_paths
+                if not ep.startswith("include/") and ep != "include"
+            ]
+
     public_includes = []
     if public_hdrs_path != None:
         public_includes.append(
@@ -1234,6 +1281,25 @@ def _new_clang_src_info_from_sources(
             exclude_paths = abs_exclude_paths,
         ))
 
+    # SPM's exclude list only excludes files from being compiled as sources,
+    # but headers in excluded directories are still available for inclusion.
+    # We need to find all header files in excluded directories and add them
+    # to all_srcs so they can be discovered and added to the BUILD file.
+    for ep in exclude_paths:
+        abs_exclude_path = paths.normalize(paths.join(abs_target_path, ep))
+        if repository_files.is_directory(repository_ctx, abs_exclude_path):
+            # Get all files in the excluded directory
+            excluded_files = repository_files.list_files_under(
+                repository_ctx,
+                abs_exclude_path,
+                exclude_paths = [],
+            )
+            # Filter to only header files
+            for f in excluded_files:
+                _, ext = paths.split_extension(f)
+                if ext in [".h", ".hpp", ".hh", ".hxx", ".inc", ".inl", ".modulemap"]:
+                    all_srcs.append(f)
+
     # Organize the source files
     # Be sure that the all_srcs and the public_includes that are passed to
     # `collect_files` are all absolute paths.  The relative_to option will
@@ -1304,6 +1370,9 @@ def _new_clang_src_info_from_sources(
 
     # GH1290: Can I remove explicit_srcs? I believe that it is obsolete.
 
+    # Detect Apple frameworks used by C source files
+    frameworks = _detect_frameworks_from_sources(repository_ctx, all_srcs)
+
     return _new_clang_src_info(
         srcs = srcs,
         explicit_srcs = explicit_srcs,
@@ -1312,6 +1381,7 @@ def _new_clang_src_info_from_sources(
         public_includes = public_includes,
         private_includes = private_includes,
         modulemap_path = organized_files.modulemap,
+        frameworks = frameworks,
     )
 
 def _new_clang_src_info(
@@ -1321,7 +1391,8 @@ def _new_clang_src_info(
         textual_hdrs = [],
         public_includes = [],
         private_includes = [],
-        modulemap_path = None):
+        modulemap_path = None,
+        frameworks = []):
     return struct(
         organized_srcs = clang_files.organize_srcs(srcs),
         explicit_srcs = explicit_srcs,
@@ -1330,6 +1401,7 @@ def _new_clang_src_info(
         public_includes = public_includes,
         private_includes = private_includes,
         modulemap_path = modulemap_path,
+        frameworks = frameworks,
     )
 
 # MARK: - Objc Source Info
diff --git a/swiftpkg/internal/swiftpkg_build_files.bzl b/swiftpkg/internal/swiftpkg_build_files.bzl
@@ -395,6 +395,19 @@ def _clang_target_build_file(repository_ctx, pkg_ctx, target):
             for bs in target.linker_settings.linked_frameworks
         ]))
 
+    # Add frameworks detected from source files as linkopts
+    # cc_library doesn't support sdk_frameworks, so we use -framework flags
+    if clang_src_info.frameworks:
+        for framework in clang_src_info.frameworks:
+            platform_conditions = bazel_apple_platforms.for_framework(framework)
+            for pc in platform_conditions:
+                linkopts.append(
+                    bzl_selects.new(
+                        value = "-framework {}".format(framework),
+                        condition = pc,
+                    ),
+                )
+
     # Assemble attributes
 
     attrs = {

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+# AWS CRT Swift Example`
	`2`	`+`
	`3`	`+This example demonstrates using [aws-crt-swift](https://github.com/awslabs/aws-crt-swift) with Bazel.`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+# Intentionally blank. The content for this workspace is generated by bzlmod.`