Address review feedback.

- Use `IDENTIFIER_(Differentiation)` macro.
- Add `differentiable_programming` lit support.

Author: dan-zheng

include/swift/AST/KnownIdentifiers.def

@@ -53,7 +53,7 @@ IDENTIFIER(decode)
 IDENTIFIER(decodeIfPresent)
 IDENTIFIER(Decoder)
 IDENTIFIER(decoder)
-IDENTIFIER_WITH_NAME(Differentiation, "_Differentiation")
+IDENTIFIER_(Differentiation)
 IDENTIFIER(dynamicallyCall)
 IDENTIFIER(dynamicMember)
 IDENTIFIER(Element)

test/CMakeLists.txt

@@ -134,6 +134,7 @@ normalize_boolean_spelling(SWIFT_AST_VERIFIER)
 normalize_boolean_spelling(SWIFT_ASAN_BUILD)
 normalize_boolean_spelling(SWIFT_BUILD_SYNTAXPARSERLIB)
 normalize_boolean_spelling(SWIFT_ENABLE_SOURCEKIT_TESTS)
+normalize_boolean_spelling(SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING)
 is_build_type_optimized("${SWIFT_STDLIB_BUILD_TYPE}" SWIFT_OPTIMIZED)
 
 set(profdata_merge_worker
@@ -305,6 +306,10 @@ _Block_release(void) { }\n")
 
       list(APPEND LIT_ARGS "--xunit-xml-output=${SWIFT_TEST_RESULTS_DIR}/lit-tests.xml")
 
+      if(SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING)
+        list(APPEND LIT_ARGS "--param" "differentiable_programming")
+      endif()
+
       foreach(test_subset ${TEST_SUBSETS})
         set(directories)
         set(dependencies ${test_dependencies})

test/Differentiation/differentiable_protocol.swift

@@ -1,4 +1,5 @@
 // RUN: %target-typecheck-verify-swift
+// REQUIRES: differentiable_programming
 
 import _Differentiation
 

test/lit.cfg

@@ -345,6 +345,10 @@ swift_version = lit_config.params.get('swift-version',
 lit_config.note('Compiling with -swift-version ' + swift_version)
 config.swift_test_options = '-swift-version ' + swift_version
 
+differentiable_programming = lit_config.params.get('differentiable_programming', None)
+if differentiable_programming is not None:
+    config.available_features.add('differentiable_programming')
+
 test_options = os.environ.get('SWIFT_TEST_OPTIONS')
 if test_options:
     config.swift_test_options += ' '

test/lit.site.cfg.in

@@ -118,6 +118,9 @@ else:
 if '@SWIFT_INCLUDE_TOOLS@' == 'TRUE':
     config.available_features.add('swift_tools_extra')
 
+if "@SWIFT_ENABLE_EXPERIMENTAL_DIFFERENTIABLE_PROGRAMMING@" == "TRUE":
+    config.available_features.add('differentiable_programming')
+
 # Let the main config do the real work.
 if config.test_exec_root is None:
     config.test_exec_root = os.path.dirname(os.path.realpath(__file__))