Support both dynamic and static framworks in ios C library

PiperOrigin-RevId: 357516469
Change-Id: I8a3933a1a3e2c3742201b1b571b208eca5efb34c

tensorflow/lite/g3doc/guide/build_ios.md

@@ -10,8 +10,9 @@ details on how to use them in your iOS projects.
 
 In some cases, you might wish to use a local build of TensorFlow Lite, for
 example when you want to make local changes to TensorFlow Lite and test those
-changes in your iOS app. To create a universal iOS framework for TensorFlow Lite
+changes in your iOS app or you prefer using static framework to our provided
-locally, you need to build it using Bazel on a macOS machine.
+dynamic one. To create a universal iOS framework for TensorFlow Lite locally,
+you need to build it using Bazel on a macOS machine.
 
 ### Install Xcode
 
@@ -42,7 +43,7 @@ Run the `./configure` script in the root TensorFlow checkout directory, and
 answer "Yes" when the script asks if you wish to build TensorFlow with iOS
 support.
 
-### Build TensorFlowLiteC framework
+### Build TensorFlowLiteC dynamic framework (recommended)
 
 Note: This step is not necessary if (1) you are using Bazel for your app, or (2)
 you only want to test local changes to the Swift or Objective-C APIs. In these
@@ -64,6 +65,22 @@ arm64, and x86_64 (but no i386). To see the full list of build flags used when
 you specify `--config=ios_fat`, please refer to the iOS configs section in the
 [`.bazelrc` file][bazelrc].
 
+### Build TensorFlowLiteC static framework
+
+By default, we only distribute the dynamic framework via Cocoapods. If you want
+to use the static framework instead, you can build the `TensorFlowLiteC` static
+framework with the following command:
+
+```
+bazel build --config=ios_fat -c opt \
+  //tensorflow/lite/ios:TensorFlowLiteC_static_framework
+```
+
+The command will generate a file named `TensorFlowLiteC_static_framework.zip`
+under `bazel-bin/tensorflow/lite/ios/` directory under your TensorFlow root
+directory. This static framework can be used in the exact same way as the
+dynamic one.
+
 ## Use in your own application
 
 ### CocoaPods developers

tensorflow/lite/ios/BUILD.apple

@@ -5,7 +5,7 @@ load(
     "//tensorflow/lite/ios:ios.bzl",
     "TFL_MINIMUM_OS_VERSION",
     "strip_common_include_path_prefix",
-    "tflite_ios_static_framework",
+    "tflite_ios_framework",
 )
 load("@build_bazel_rules_apple//apple:ios.bzl", "ios_static_framework")
 
@@ -99,7 +99,7 @@ strip_common_include_path_prefix(
 )
 
 # bazel build -c opt --config=ios_fat //tensorflow/lite/ios:TensorFlowLiteC_framework
-tflite_ios_static_framework(
+tflite_ios_framework(
     name = "TensorFlowLiteC_framework",
     hdrs = [
         ":c_api.h",
@@ -115,6 +115,23 @@ tflite_ios_static_framework(
     ],
 )
 
+# Similar to TensorFlowLiteC_framework but this is a static framework and symbol
+# hiding is not applied. Note both have the same bundle name.
+ios_static_framework(
+    name = "TensorFlowLiteC_static_framework",
+    hdrs = [
+        ":c_api.h",
+        ":common.h",
+        ":xnnpack_delegate.h",
+        "//tensorflow/lite/c:c_api_types.h",
+    ],
+    bundle_name = "TensorFlowLiteC",
+    minimum_os_version = TFL_MINIMUM_OS_VERSION,
+    deps = [
+        ":tensorflow_lite_c",
+    ],
+)
+
 # This target builds the flex delegate as a separate static framework, which
 # does not include the TensorFlow Lite runtime. As this target does not contain
 # TensorFlow Lite runtime, it is intended to be linked along with the
@@ -140,7 +157,7 @@ ios_static_framework(
 # TensorFlowLiteC framework above in a composable way.
 #
 # bazel build -c opt --config=ios_fat //tensorflow/lite/ios:TensorFlowLiteCCoreML_framework
-tflite_ios_static_framework(
+tflite_ios_framework(
     name = "TensorFlowLiteCCoreML_framework",
     hdrs = [
         ":coreml_delegate.h",
@@ -159,7 +176,7 @@ tflite_ios_static_framework(
 # TensorFlowLiteC framework above in a composable way.
 #
 # bazel build -c opt --config=ios_fat //tensorflow/lite/ios:TensorFlowLiteCMetal_framework
-tflite_ios_static_framework(
+tflite_ios_framework(
     name = "TensorFlowLiteCMetal_framework",
     hdrs = [
         ":metal_delegate.h",
@@ -208,5 +225,6 @@ build_test(
         ":TensorFlowLiteCMetal_framework",
         ":TensorFlowLiteC_framework",
         ":TensorFlowLiteSelectTfOps_framework",
+        ":TensorFlowLiteC_static_framework",
     ],
 )

tensorflow/lite/ios/ios.bzl

@@ -17,17 +17,17 @@ TFL_DISABLED_SANITIZER_TAGS = [
     "notsan",
 ]
 
-# iOS static framework with symbol allowlist. Exported C++ symbols might cause
+# iOS framework with symbol allowlist. Exported C++ symbols might cause symbol
-# symbol collision with other libraries. List of symbols to allowlist can be
+# collision with other libraries. List of symbols to allowlist can be
 # generated by running `nm -m -g FRAMEWORK_LIBRARY | grep _TfLite` for framework
 # built with `ios_static_framework` rule.
-def tflite_ios_static_framework(
+def tflite_ios_framework(
         name,
         bundle_name,
         allowlist_symbols_file,
         exclude_resources = True,
         **kwargs):
-    """TFLite variant of ios_static_framework with symbol hiding.
+    """Apply symbol hiding to the output of ios_static_framework.
 
     Args:
       name: The name of the target.