Revert "Merge pull request #60368 from etcwilde/ewilde/backdeploy56"

This reverts commit a3941bf, reversing
changes made to b39302a.

Author: etcwilde

include/swift/Frontend/BackDeploymentLibs.def

@@ -28,6 +28,5 @@ BACK_DEPLOYMENT_LIB((5, 0), all, "swiftCompatibility50")
 BACK_DEPLOYMENT_LIB((5, 1), all, "swiftCompatibility51")
 BACK_DEPLOYMENT_LIB((5, 0), executable, "swiftCompatibilityDynamicReplacements")
 BACK_DEPLOYMENT_LIB((5, 4), all, "swiftCompatibilityConcurrency")
-BACK_DEPLOYMENT_LIB((5, 6), all, "swiftCompatibility56")
 
 #undef BACK_DEPLOYMENT_LIB

lib/Driver/DarwinToolChains.cpp

@@ -411,8 +411,6 @@ toolchains::Darwin::addArgsToLinkStdlib(ArgStringList &Arguments,
       runtimeCompatibilityVersion = llvm::VersionTuple(5, 1);
     } else if (value.equals("5.5")) {
       runtimeCompatibilityVersion = llvm::VersionTuple(5, 5);
-    } else if (value.equals("5.6")) {
-      runtimeCompatibilityVersion = llvm::VersionTuple(5, 6);
     } else if (value.equals("none")) {
       runtimeCompatibilityVersion = None;
     } else {

lib/Frontend/CompilerInvocation.cpp

@@ -2292,8 +2292,6 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
         runtimeCompatibilityVersion = llvm::VersionTuple(5, 1);
       } else if (version.equals("5.5")) {
         runtimeCompatibilityVersion = llvm::VersionTuple(5, 5);
-      } else if (version.equals("5.6")) {
-        runtimeCompatibilityVersion = llvm::VersionTuple(5, 6);
       } else {
         Diags.diagnose(SourceLoc(), diag::error_invalid_arg_value,
                        versionArg->getAsString(Args), version);

stdlib/CMakeLists.txt

@@ -39,8 +39,6 @@ include(StdlibOptions)
 # End of user-configurable options.
 #
 
-set(SWIFT_STDLIB_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}")
-
 # Remove llvm-project/llvm/include directory from -I search part when building
 # the stdlib. We have our own fork of LLVM includes (Support, ADT) in
 # stdlib/include/llvm and we don't want to silently use headers from LLVM.

stdlib/toolchain/CMakeLists.txt

@@ -50,7 +50,6 @@ if(SWIFT_STDLIB_SUPPORT_BACK_DEPLOYMENT)
   add_subdirectory(legacy_layouts)
   add_subdirectory(Compatibility50)
   add_subdirectory(Compatibility51)
-  add_subdirectory(Compatibility56)
   add_subdirectory(CompatibilityDynamicReplacements)
   add_subdirectory(CompatibilityConcurrency)
 endif()