diff --git a/lib/Immediate/Immediate.cpp b/lib/Immediate/Immediate.cpp
index 27c4632245db8..d1cca84e85699 100644
--- a/lib/Immediate/Immediate.cpp
+++ b/lib/Immediate/Immediate.cpp
@@ -239,7 +239,7 @@ int swift::RunImmediately(CompilerInstance &CI,
   // This must be done here, before any library loading has been done, to avoid
   // racing with the static initializers in user code.
   // Setup interpreted process arguments.
-  using ArgOverride = void (*)(const char **, int);
+  using ArgOverride = void (* SWIFT_CC(swift))(const char **, int);
 #if defined(_WIN32)
   auto stdlib = loadSwiftRuntime(Context.SearchPathOpts.RuntimeLibraryPaths);
   if (!stdlib) {
diff --git a/stdlib/CMakeLists.txt b/stdlib/CMakeLists.txt
index 38c2b7f7827dc..a21db60bb1e40 100644
--- a/stdlib/CMakeLists.txt
+++ b/stdlib/CMakeLists.txt
@@ -127,6 +127,10 @@ option(SWIFT_STDLIB_PASSTHROUGH_METADATA_ALLOCATOR
        "Build stdlib without a custom implementation of MetadataAllocator, relying on malloc+free instead."
        FALSE)
 
+option(SWIFT_STDLIB_HAS_COMMANDLINE
+       "Build stdlib with the CommandLine enum and support for argv/argc."
+       TRUE)
+
 option(SWIFT_BUILD_TEST_SUPPORT_MODULES
        "Whether to build StdlibUnittest and other test support modules. Defaults to On when SWIFT_BUILD_SDK_OVERLAY is On, or when SWIFT_INCLUDE_TESTS is On."
        "${SWIFT_BUILD_TEST_SUPPORT_MODULES_default}")
diff --git a/stdlib/cmake/modules/SwiftSource.cmake b/stdlib/cmake/modules/SwiftSource.cmake
index f5ade74eab0e9..de4de4bc2c688 100644
--- a/stdlib/cmake/modules/SwiftSource.cmake
+++ b/stdlib/cmake/modules/SwiftSource.cmake
@@ -289,6 +289,10 @@ function(_add_target_variant_swift_compile_flags
     list(APPEND result "-D" "SWIFT_RUNTIME_OS_VERSIONING")
   endif()
 
+  if(SWIFT_STDLIB_HAS_COMMANDLINE)
+    list(APPEND result "-D" "SWIFT_STDLIB_HAS_COMMANDLINE")
+  endif()
+
   if(SWIFT_STDLIB_HAS_STDIN)
     list(APPEND result "-D" "SWIFT_STDLIB_HAS_STDIN")
   endif()
diff --git a/stdlib/private/SwiftPrivateLibcExtras/CMakeLists.txt b/stdlib/private/SwiftPrivateLibcExtras/CMakeLists.txt
index 5daf252fe7561..3c227afdc384a 100644
--- a/stdlib/private/SwiftPrivateLibcExtras/CMakeLists.txt
+++ b/stdlib/private/SwiftPrivateLibcExtras/CMakeLists.txt
@@ -3,6 +3,13 @@ if(SWIFT_STDLIB_HAS_ENVIRON)
   set(swift_private_libc_extras_flags "-D" "SWIFT_STDLIB_HAS_ENVIRON")
 endif()
 
+set(swift_private_libc_extras_incorporate_object_libraries)
+if(SWIFT_STDLIB_HAS_COMMANDLINE)
+  list(APPEND swift_private_libc_extras_flags "-D" "SWIFT_STDLIB_HAS_COMMANDLINE")
+else()
+  set(swift_private_libc_extras_incorporate_object_libraries "swiftCommandLineSupport")
+endif()
+
 add_swift_target_library(swiftSwiftPrivateLibcExtras ${SWIFT_STDLIB_LIBRARY_BUILD_TYPES} IS_STDLIB
   # This file should be listed the first.  Module name is inferred from the
   # filename.
@@ -25,5 +32,6 @@ add_swift_target_library(swiftSwiftPrivateLibcExtras ${SWIFT_STDLIB_LIBRARY_BUIL
   SWIFT_MODULE_DEPENDS_CYGWIN Glibc
   SWIFT_MODULE_DEPENDS_HAIKU Glibc
   SWIFT_MODULE_DEPENDS_WINDOWS CRT WinSDK
+  INCORPORATE_OBJECT_LIBRARIES ${swift_private_libc_extras_incorporate_object_libraries}
   INSTALL_IN_COMPONENT stdlib-experimental
   DARWIN_INSTALL_NAME_DIR "${SWIFT_DARWIN_STDLIB_PRIVATE_INSTALL_NAME_DIR}")
diff --git a/stdlib/private/SwiftPrivateLibcExtras/Subprocess.swift b/stdlib/private/SwiftPrivateLibcExtras/Subprocess.swift
index 11df099afdc38..07d1ebd7673bd 100644
--- a/stdlib/private/SwiftPrivateLibcExtras/Subprocess.swift
+++ b/stdlib/private/SwiftPrivateLibcExtras/Subprocess.swift
@@ -57,6 +57,18 @@ public enum ProcessTerminationStatus : CustomStringConvertible {
   }
 }
 
+#if !SWIFT_STDLIB_HAS_COMMANDLINE
+@_silgen_name("_swift_stdlib_getUnsafeArgvArgc")
+internal func _swift_stdlib_getUnsafeArgvArgc(_: UnsafeMutablePointer<Int32>) -> UnsafeMutablePointer<UnsafeMutablePointer<Int8>?>
+
+public enum CommandLine {
+  public static var arguments: [String] = {
+    var argc: Int32 = 0
+    var unsafeArgv = _swift_stdlib_getUnsafeArgvArgc(&argc)
+    return (0 ..< Int(argc)).map { String(cString: unsafeArgv[$0]!) }
+  }()
+}
+#endif // !SWIFT_STDLIB_HAS_COMMANDLINE
 
 #if os(Windows)
 public func spawnChild(_ args: [String])
diff --git a/stdlib/public/CMakeLists.txt b/stdlib/public/CMakeLists.txt
index 3c6fab55c9b0a..79e814e5804dd 100644
--- a/stdlib/public/CMakeLists.txt
+++ b/stdlib/public/CMakeLists.txt
@@ -55,6 +55,7 @@ if(CXX_SUPPORTS_EXIT_TIME_DESTRUCTORS_WARNING)
 endif()
 
 add_subdirectory(SwiftShims)
+add_subdirectory(CommandLineSupport)
 
 # This static library is shared across swiftCore and swiftReflection
 if(SWIFT_BUILD_STDLIB OR SWIFT_BUILD_REMOTE_MIRROR)
diff --git a/stdlib/public/CommandLineSupport/CMakeLists.txt b/stdlib/public/CommandLineSupport/CMakeLists.txt
new file mode 100644
index 0000000000000..697e0e21b8768
--- /dev/null
+++ b/stdlib/public/CommandLineSupport/CMakeLists.txt
@@ -0,0 +1,8 @@
+add_swift_target_library(swiftCommandLineSupport
+  STATIC DONT_EMBED_BITCODE NOSWIFTRT
+  CommandLine.cpp
+  C_COMPILE_FLAGS ${SWIFT_RUNTIME_CXX_FLAGS}
+  LINK_FLAGS ${SWIFT_RUNTIME_LINK_FLAGS}
+  SWIFT_COMPILE_FLAGS ${SWIFT_STANDARD_LIBRARY_SWIFT_FLAGS}
+  INSTALL_IN_COMPONENT never_install
+  )
diff --git a/stdlib/public/stubs/CommandLine.cpp b/stdlib/public/CommandLineSupport/CommandLine.cpp
similarity index 95%
rename from stdlib/public/stubs/CommandLine.cpp
rename to stdlib/public/CommandLineSupport/CommandLine.cpp
index b487b168939c0..09f75ac3bafb6 100644
--- a/stdlib/public/stubs/CommandLine.cpp
+++ b/stdlib/public/CommandLineSupport/CommandLine.cpp
@@ -39,7 +39,8 @@
 static char **_swift_stdlib_ProcessOverrideUnsafeArgv = nullptr;
 static int _swift_stdlib_ProcessOverrideUnsafeArgc = 0;
 
-SWIFT_RUNTIME_STDLIB_API
+// This needs to findable by dlopen() for JIT purposes (see Immediate.cpp).
+SWIFT_CC(swift) extern "C" SWIFT_ATTRIBUTE_FOR_EXPORTS
 void _swift_stdlib_overrideUnsafeArgvArgc(char **argv, int argc) {
   _swift_stdlib_ProcessOverrideUnsafeArgv = argv;
   _swift_stdlib_ProcessOverrideUnsafeArgc = argc;
@@ -51,7 +52,7 @@ void _swift_stdlib_overrideUnsafeArgvArgc(char **argv, int argc) {
 extern "C" char ***_NSGetArgv(void);
 extern "C" int *_NSGetArgc(void);
 
-SWIFT_RUNTIME_STDLIB_API
+SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL
 char **_swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
   assert(outArgLen != nullptr);
 
@@ -64,7 +65,7 @@ char **_swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
   return *_NSGetArgv();
 }
 #elif defined(__linux__) || defined(__CYGWIN__)
-SWIFT_RUNTIME_STDLIB_API
+SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL
 char **_swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
   assert(outArgLen != nullptr);
 
@@ -98,7 +99,7 @@ char **_swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
 #elif defined(_WIN32)
 #include <stdlib.h>
 
-SWIFT_RUNTIME_STDLIB_API
+SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL
 char **_swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
   assert(outArgLen != nullptr);
 
@@ -165,7 +166,7 @@ char **_swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
 #include <sys/types.h>
 #include <unistd.h>
 
-SWIFT_RUNTIME_STDLIB_API
+SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL
 char **_swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
   assert(outArgLen != nullptr);
 
@@ -216,7 +217,7 @@ char **_swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
 #include <wasi/api.h>
 #include <wasi/libc.h>
 
-SWIFT_RUNTIME_STDLIB_API
+SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL
 char **_swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
   assert(outArgLen != nullptr);
 
@@ -257,7 +258,7 @@ char **_swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
 #include <sys/sysctl.h>
 #include <sys/exec.h>
 
-SWIFT_RUNTIME_STDLIB_API
+SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL
 char ** _swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
   assert(outArgLen != nullptr);
   if (_swift_stdlib_ProcessOverrideUnsafeArgv) {
@@ -289,7 +290,7 @@ char ** _swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
   return argv_copy;
 }
 #else // Add your favorite OS's command line arg grabber here.
-SWIFT_RUNTIME_STDLIB_API
+SWIFT_CC(swift) SWIFT_RUNTIME_STDLIB_INTERNAL
 char **_swift_stdlib_getUnsafeArgvArgc(int *outArgLen) {
   if (_swift_stdlib_ProcessOverrideUnsafeArgv) {
     *outArgLen = _swift_stdlib_ProcessOverrideUnsafeArgc;
diff --git a/stdlib/public/SwiftShims/RuntimeStubs.h b/stdlib/public/SwiftShims/RuntimeStubs.h
index 96f73b3830d33..e17c3f766a30d 100644
--- a/stdlib/public/SwiftShims/RuntimeStubs.h
+++ b/stdlib/public/SwiftShims/RuntimeStubs.h
@@ -31,14 +31,6 @@ SWIFT_RUNTIME_STDLIB_API
 __swift_ssize_t
 swift_stdlib_readLine_stdin(unsigned char * _Nullable * _Nonnull LinePtr);
 
-SWIFT_RUNTIME_STDLIB_API
-char * _Nullable * _Nonnull
-_swift_stdlib_getUnsafeArgvArgc(int * _Nonnull outArgLen);
-  
-SWIFT_RUNTIME_STDLIB_API
-void
-_swift_stdlib_overrideUnsafeArgvArgc(char * _Nullable * _Nonnull argv, int argc);
-
 SWIFT_END_NULLABILITY_ANNOTATIONS
 
 #ifdef __cplusplus
diff --git a/stdlib/public/core/CMakeLists.txt b/stdlib/public/core/CMakeLists.txt
index c2ad36ab170a3..c7bf03eeca4f1 100644
--- a/stdlib/public/core/CMakeLists.txt
+++ b/stdlib/public/core/CMakeLists.txt
@@ -302,6 +302,15 @@ if(SWIFT_CHECK_ESSENTIAL_STDLIB)
   target_link_libraries(swift_stdlib_essential ${RUNTIME_DEPENDENCY})
 endif()
 
+set(swift_core_incorporate_object_libraries)
+list(APPEND swift_core_incorporate_object_libraries swiftRuntime)
+list(APPEND swift_core_incorporate_object_libraries swiftLLVMSupport)
+list(APPEND swift_core_incorporate_object_libraries swiftDemangling)
+list(APPEND swift_core_incorporate_object_libraries swiftStdlibStubs)
+if(SWIFT_STDLIB_HAS_COMMANDLINE)
+  list(APPEND swift_core_incorporate_object_libraries swiftCommandLineSupport)
+endif()
+
 set(swiftCore_common_options
                   IS_STDLIB IS_STDLIB_CORE
                     ${SWIFTLIB_SOURCES}
@@ -314,7 +323,7 @@ set(swiftCore_common_options
                   PRIVATE_LINK_LIBRARIES
                     ${swift_core_private_link_libraries}
                   INCORPORATE_OBJECT_LIBRARIES
-                    swiftRuntime swiftLLVMSupport swiftDemangling swiftStdlibStubs
+                    ${swift_core_incorporate_object_libraries}
                   FRAMEWORK_DEPENDS
                     ${swift_core_framework_depends})
 
diff --git a/stdlib/public/core/CommandLine.swift b/stdlib/public/core/CommandLine.swift
index 2d311097a3f47..cdfa7a71856cd 100644
--- a/stdlib/public/core/CommandLine.swift
+++ b/stdlib/public/core/CommandLine.swift
@@ -12,6 +12,12 @@
 
 import SwiftShims
 
+#if SWIFT_STDLIB_HAS_COMMANDLINE
+
+@_silgen_name("_swift_stdlib_getUnsafeArgvArgc")
+internal func _swift_stdlib_getUnsafeArgvArgc(_: UnsafeMutablePointer<Int32>)
+  -> UnsafeMutablePointer<UnsafeMutablePointer<Int8>?>
+
 /// Command-line arguments for the current process.
 @frozen // namespace
 public enum CommandLine {
@@ -49,3 +55,5 @@ public enum CommandLine {
   public static var arguments: [String]
     = (0..<Int(argc)).map { String(cString: _unsafeArgv[$0]!) }
 }
+
+#endif // SWIFT_STDLIB_HAS_COMMANDLINE
diff --git a/stdlib/public/stubs/CMakeLists.txt b/stdlib/public/stubs/CMakeLists.txt
index 54f164a7f61d8..909cfd537e79a 100644
--- a/stdlib/public/stubs/CMakeLists.txt
+++ b/stdlib/public/stubs/CMakeLists.txt
@@ -1,6 +1,5 @@
 set(swift_stubs_sources
     Assert.cpp
-    CommandLine.cpp
     GlobalObjects.cpp
     LibcShims.cpp
     Random.cpp
diff --git a/test/stdlib/POSIX.swift b/test/stdlib/POSIX.swift
index f0ca55a4bb913..a551de9f6afd9 100644
--- a/test/stdlib/POSIX.swift
+++ b/test/stdlib/POSIX.swift
@@ -4,6 +4,7 @@
 // UNSUPPORTED: OS=wasi
 
 import StdlibUnittest
+import SwiftPrivateLibcExtras
 #if canImport(Darwin)
   import Darwin
 #elseif canImport(Glibc)
diff --git a/test/stdlib/PrintFloat.swift.gyb b/test/stdlib/PrintFloat.swift.gyb
index 216216712b56e..e085db31e8d2a 100644
--- a/test/stdlib/PrintFloat.swift.gyb
+++ b/test/stdlib/PrintFloat.swift.gyb
@@ -10,6 +10,7 @@
 // UNSUPPORTED: CPU=arm64_32 && OS=watchos
 
 import StdlibUnittest
+import SwiftPrivateLibcExtras
 #if canImport(Darwin)
   import Darwin
 #elseif canImport(Glibc)
diff --git a/utils/build-presets.ini b/utils/build-presets.ini
index be4b20078e0ba..2bdadef0b787c 100644
--- a/utils/build-presets.ini
+++ b/utils/build-presets.ini
@@ -2473,6 +2473,7 @@ swift-stdlib-has-environ=0
 swift-runtime-static-image-inspection=1
 swift-stdlib-single-threaded-runtime=1
 swift-stdlib-os-versioning=0
+swift-stdlib-has-commandline=0
 swift-stdlib-lto=full
 extra-cmake-options=
     -DSWIFT_ENABLE_DISPATCH:BOOL=FALSE
diff --git a/utils/build-script-impl b/utils/build-script-impl
index 262b7d314f7e8..e42717bdf90ff 100755
--- a/utils/build-script-impl
+++ b/utils/build-script-impl
@@ -211,6 +211,7 @@ KNOWN_SETTINGS=(
     swift-runtime-static-image-inspection         "0"               "whether to build stdlib assuming the runtime environment only supports a single runtime image with Swift code"
     swift-stdlib-single-threaded-runtime          "0"               "whether to build stdlib as a single-threaded runtime only"
     swift-stdlib-os-versioning                    "1"               "whether to build stdlib with availability based on OS versions (Darwin only)"
+    swift-stdlib-has-commandline                  "1"               "whether to build stdlib with the CommandLine enum and support for argv/argc"
     swift-stdlib-stable-abi                       ""                "should stdlib be built with stable ABI, if not set defaults to true on Darwin, false otherwise"
     swift-stdlib-has-darwin-libmalloc             "1"               "whether the Darwin build of stdlib can use extended libmalloc APIs"
     swift-stdlib-has-asl                          ""                "whether the stdlib can use the asl_log API, defaults to true on Darwin, false otherwise"
@@ -1990,6 +1991,7 @@ for host in "${ALL_HOSTS[@]}"; do
                     -DSWIFT_STDLIB_HAS_DLADDR:BOOL=$(true_false "${SWIFT_STDLIB_HAS_DLADDR}")
                     -DSWIFT_RUNTIME_STATIC_IMAGE_INSPECTION:BOOL=$(true_false "${SWIFT_RUNTIME_STATIC_IMAGE_INSPECTION}")
                     -DSWIFT_STDLIB_OS_VERSIONING:BOOL=$(true_false "${SWIFT_STDLIB_OS_VERSIONING}")
+                    -DSWIFT_STDLIB_HAS_COMMANDLINE:BOOL=$(true_false "${SWIFT_STDLIB_HAS_COMMANDLINE}")
                     -DSWIFT_STDLIB_HAS_DARWIN_LIBMALLOC:BOOL=$(true_false "${SWIFT_STDLIB_HAS_DARWIN_LIBMALLOC}")
                     -DSWIFT_STDLIB_HAS_STDIN:BOOL=$(true_false "${SWIFT_STDLIB_HAS_STDIN}")
                     -DSWIFT_STDLIB_HAS_ENVIRON:BOOL=$(true_false "${SWIFT_STDLIB_HAS_ENVIRON}")