Add an API to compile a .swiftinterface file into a .swiftmodule. (…

…#1085)

(cherry picked from commit 47b4648)

doc/api.md

@@ -135,6 +135,40 @@ A tuple containing three elements:
           will be `None`.
 
 
+<a id="swift_common.compile_module_interface"></a>
+
+## swift_common.compile_module_interface
+
+<pre>
+swift_common.compile_module_interface(<a href="#swift_common.compile_module_interface-actions">actions</a>, <a href="#swift_common.compile_module_interface-compilation_contexts">compilation_contexts</a>, <a href="#swift_common.compile_module_interface-feature_configuration">feature_configuration</a>,
+                                      <a href="#swift_common.compile_module_interface-module_name">module_name</a>, <a href="#swift_common.compile_module_interface-swiftinterface_file">swiftinterface_file</a>, <a href="#swift_common.compile_module_interface-swift_infos">swift_infos</a>, <a href="#swift_common.compile_module_interface-swift_toolchain">swift_toolchain</a>)
+</pre>
+
+Compiles a Swift module interface.
+
+**PARAMETERS**
+
+
+| Name  | Description | Default Value |
+| :------------- | :------------- | :------------- |
+| <a id="swift_common.compile_module_interface-actions"></a>actions |  The context's <code>actions</code> object.   |  none |
+| <a id="swift_common.compile_module_interface-compilation_contexts"></a>compilation_contexts |  A list of <code>CcCompilationContext</code>s that represent C/Objective-C requirements of the target being compiled, such as Swift-compatible preprocessor defines, header search paths, and so forth. These are typically retrieved from the <code>CcInfo</code> providers of a target's dependencies.   |  none |
+| <a id="swift_common.compile_module_interface-feature_configuration"></a>feature_configuration |  A feature configuration obtained from <code>swift_common.configure_features</code>.   |  none |
+| <a id="swift_common.compile_module_interface-module_name"></a>module_name |  The name of the Swift module being compiled. This must be present and valid; use <code>swift_common.derive_module_name</code> to generate a default from the target's label if needed.   |  none |
+| <a id="swift_common.compile_module_interface-swiftinterface_file"></a>swiftinterface_file |  The Swift module interface file to compile.   |  none |
+| <a id="swift_common.compile_module_interface-swift_infos"></a>swift_infos |  A list of <code>SwiftInfo</code> providers from dependencies of the target being compiled.   |  none |
+| <a id="swift_common.compile_module_interface-swift_toolchain"></a>swift_toolchain |  The <code>SwiftToolchainInfo</code> provider of the toolchain.   |  none |
+
+**RETURNS**
+
+A Swift module context (as returned by `swift_common.create_module`)
+  that contains the Swift (and potentially C/Objective-C) compilation
+  prerequisites of the compiled module. This should typically be
+  propagated by a `SwiftInfo` provider of the calling rule, and the
+  `CcCompilationContext` inside the Clang module substructure should be
+  propagated by the `CcInfo` provider of the calling rule.
+
+
 <a id="swift_common.configure_features"></a>
 
 ## swift_common.configure_features

doc/rules.md

@@ -242,10 +242,10 @@ swift_grpc_library(
 ## swift_import
 
 <pre>
-swift_import(<a href="#swift_import-name">name</a>, <a href="#swift_import-archives">archives</a>, <a href="#swift_import-data">data</a>, <a href="#swift_import-deps">deps</a>, <a href="#swift_import-module_name">module_name</a>, <a href="#swift_import-swiftdoc">swiftdoc</a>, <a href="#swift_import-swiftmodule">swiftmodule</a>)
+swift_import(<a href="#swift_import-name">name</a>, <a href="#swift_import-archives">archives</a>, <a href="#swift_import-data">data</a>, <a href="#swift_import-deps">deps</a>, <a href="#swift_import-module_name">module_name</a>, <a href="#swift_import-swiftdoc">swiftdoc</a>, <a href="#swift_import-swiftinterface">swiftinterface</a>, <a href="#swift_import-swiftmodule">swiftmodule</a>)
 </pre>
 
-Allows for the use of precompiled Swift modules as dependencies in other
+Allows for the use of Swift textual module interfaces and/or precompiled Swift modules as dependencies in other
 `swift_library` and `swift_binary` targets.
 
 
@@ -255,12 +255,13 @@ Allows for the use of precompiled Swift modules as dependencies in other
 | Name  | Description | Type | Mandatory | Default |
 | :------------- | :------------- | :------------- | :------------- | :------------- |
 | <a id="swift_import-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/concepts/labels#target-names">Name</a> | required |  |
-| <a id="swift_import-archives"></a>archives |  The list of <code>.a</code> files provided to Swift targets that depend on this target.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | required |  |
+| <a id="swift_import-archives"></a>archives |  The list of <code>.a</code> files provided to Swift targets that depend on this target.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | optional | <code>[]</code> |
 | <a id="swift_import-data"></a>data |  The list of files needed by this target at runtime.<br><br>Files and targets named in the <code>data</code> attribute will appear in the <code>*.runfiles</code> area of this target, if it has one. This may include data files needed by a binary or library, or other programs needed by it.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | optional | <code>[]</code> |
 | <a id="swift_import-deps"></a>deps |  A list of targets that are dependencies of the target being built, which will be linked into that target.<br><br>If the Swift toolchain supports implementation-only imports (<code>private_deps</code> on <code>swift_library</code>), then targets in <code>deps</code> are treated as regular (non-implementation-only) imports that are propagated both to their direct and indirect (transitive) dependents.<br><br>Allowed kinds of dependencies are:<br><br>*   <code>swift_c_module</code>, <code>swift_import</code> and <code>swift_library</code> (or anything     propagating <code>SwiftInfo</code>)<br><br>*   <code>cc_library</code> (or anything propagating <code>CcInfo</code>)<br><br>Additionally, on platforms that support Objective-C interop, <code>objc_library</code> targets (or anything propagating the <code>apple_common.Objc</code> provider) are allowed as dependencies. On platforms that do not support Objective-C interop (such as Linux), those dependencies will be **ignored.**   | <a href="https://bazel.build/concepts/labels">List of labels</a> | optional | <code>[]</code> |
 | <a id="swift_import-module_name"></a>module_name |  The name of the module represented by this target.   | String | required |  |
 | <a id="swift_import-swiftdoc"></a>swiftdoc |  The <code>.swiftdoc</code> file provided to Swift targets that depend on this target.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional | <code>None</code> |
-| <a id="swift_import-swiftmodule"></a>swiftmodule |  The <code>.swiftmodule</code> file provided to Swift targets that depend on this target.   | <a href="https://bazel.build/concepts/labels">Label</a> | required |  |
+| <a id="swift_import-swiftinterface"></a>swiftinterface |  The <code>.swiftinterface</code> file that defines the module interface for this target.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional | <code>None</code> |
+| <a id="swift_import-swiftmodule"></a>swiftmodule |  The <code>.swiftmodule</code> file provided to Swift targets that depend on this target.   | <a href="https://bazel.build/concepts/labels">Label</a> | optional | <code>None</code> |
 
 
 <a id="swift_library"></a>

swift/internal/BUILD

@@ -51,6 +51,7 @@ bzl_library(
         ":toolchain_config",
         ":utils",
         ":vfsoverlay",
+        "//swift/toolchains/config:compile_module_interface_config",
         "@bazel_skylib//lib:collections",
         "@bazel_skylib//lib:partial",
         "@bazel_skylib//lib:paths",

swift/internal/actions.bzl

@@ -30,6 +30,9 @@ swift_action_names = struct(
     # object files.
     COMPILE = "SwiftCompile",
 
+    # Compiles a `.swiftinterface` file into a `.swiftmodule` file.
+    COMPILE_MODULE_INTERFACE = "SwiftCompileModuleInterface",
+
     # Wraps a `.swiftmodule` in a `.o` file on ELF platforms so that it can be
     # linked into a binary for debugging.
     MODULEWRAP = "SwiftModuleWrap",