[IRGen] Add a CMake option to configure direct retain/release enablement.

The SWIFT_ENABLE_DIRECT_RETAIN_RELEASE option controls the default value of the option to enable direct retain/release. It's off by default, meaning direct RR is off by default. Setting SWIFT_ENABLE_DIRECT_RETAIN_RELEASE to true will build a compiler where direct RR is on by default.

rdar://163568311

Author: mikeash

CMakeLists.txt

@@ -804,6 +804,10 @@ option(SWIFT_ENABLE_EXPERIMENTAL_PARSER_VALIDATION
   "Enable experimental SwiftParser validation by default"
   FALSE)
 
+option(SWIFT_ENABLE_DIRECT_RETAIN_RELEASE
+  "Enable use of direct refcounting calls by default"
+  FALSE)
+
 cmake_dependent_option(SWIFT_BUILD_SOURCEKIT
   "Build SourceKit" TRUE
   "SWIFT_ENABLE_DISPATCH" FALSE)

include/swift/AST/IRGenOptions.h

@@ -560,7 +560,7 @@ class IRGenOptions {
   unsigned MergeableTraps : 1;
 
   /// Enable the use of swift_retain/releaseDirect functions.
-  unsigned EnableSwiftDirectRuntime : 1;
+  unsigned EnableSwiftDirectRetainRelease : 1;
 
   /// The number of threads for multi-threaded code generation.
   unsigned NumThreads = 0;
@@ -689,7 +689,7 @@ class IRGenOptions {
         EmitAsyncFramePushPopMetadata(true), EmitTypeMallocForCoroFrame(true),
         AsyncFramePointerAll(false), UseProfilingMarkerThunks(false),
         UseCoroCCX8664(false), UseCoroCCArm64(false), MergeableTraps(false),
-        EnableSwiftDirectRuntime(false),
+        EnableSwiftDirectRetainRelease(SWIFT_ENABLE_DIRECT_RETAIN_RELEASE),
         DebugInfoForProfiling(false), CmdArgs(),
         SanitizeCoverage(llvm::SanitizerCoverageOptions()),
         TypeInfoFilter(TypeInfoDumpFilter::All),

include/swift/Config.h.in

@@ -16,4 +16,6 @@
 
 #cmakedefine01 SWIFT_ENABLE_EXPERIMENTAL_PARSER_VALIDATION
 
+#cmakedefine01 SWIFT_ENABLE_DIRECT_RETAIN_RELEASE
+
 #endif // SWIFT_CONFIG_H

lib/Frontend/CompilerInvocation.cpp

@@ -4034,10 +4034,10 @@ static bool ParseIRGenArgs(IRGenOptions &Opts, ArgList &Args,
 
   Opts.MergeableTraps = Args.hasArg(OPT_mergeable_traps);
 
-  Opts.EnableSwiftDirectRuntime =
+  Opts.EnableSwiftDirectRetainRelease =
     Args.hasFlag(OPT_enable_direct_retain_release,
                  OPT_disable_direct_retain_release,
-                 Opts.EnableSwiftDirectRuntime);
+                 Opts.EnableSwiftDirectRetainRelease);
 
   Opts.EnableObjectiveCProtocolSymbolicReferences =
     Args.hasFlag(OPT_enable_objective_c_protocol_symbolic_references,

lib/IRGen/GenHeap.cpp

@@ -1000,7 +1000,7 @@ void IRGenFunction::emitNativeStrongRetain(llvm::Value *value,
   FunctionPointer function;
   if (atomicity == Atomicity::Atomic &&
       IGM.TargetInfo.HasSwiftSwiftDirectRuntimeLibrary &&
-      getOptions().EnableSwiftDirectRuntime)
+      getOptions().EnableSwiftDirectRetainRelease)
     function = IGM.getNativeStrongRetainDirectFunctionPointer();
   else if (atomicity == Atomicity::Atomic)
     function = IGM.getNativeStrongRetainFunctionPointer();
@@ -1265,7 +1265,7 @@ void IRGenFunction::emitNativeStrongRelease(llvm::Value *value,
   llvm::Constant *function;
   if (atomicity == Atomicity::Atomic &&
       IGM.TargetInfo.HasSwiftSwiftDirectRuntimeLibrary &&
-      getOptions().EnableSwiftDirectRuntime)
+      getOptions().EnableSwiftDirectRetainRelease)
     function = IGM.getNativeStrongReleaseDirectFn();
   else if (atomicity == Atomicity::Atomic)
     function = IGM.getNativeStrongReleaseFn();
@@ -1373,7 +1373,7 @@ void IRGenFunction::emitBridgeStrongRetain(llvm::Value *value,
   llvm::Constant *function;
   if (atomicity == Atomicity::Atomic &&
       IGM.TargetInfo.HasSwiftSwiftDirectRuntimeLibrary &&
-      getOptions().EnableSwiftDirectRuntime)
+      getOptions().EnableSwiftDirectRetainRelease)
     function = IGM.getBridgeObjectStrongRetainDirectFn();
   else if (atomicity == Atomicity::Atomic)
     function = IGM.getBridgeObjectStrongRetainFn();
@@ -1387,7 +1387,7 @@ void IRGenFunction::emitBridgeStrongRelease(llvm::Value *value,
   llvm::Constant *function;
   if (atomicity == Atomicity::Atomic &&
       IGM.TargetInfo.HasSwiftSwiftDirectRuntimeLibrary &&
-      getOptions().EnableSwiftDirectRuntime)
+      getOptions().EnableSwiftDirectRetainRelease)
     function = IGM.getBridgeObjectStrongReleaseDirectFn();
   else if (atomicity == Atomicity::Atomic)
     function = IGM.getBridgeObjectStrongReleaseFn();

lib/IRGen/IRGenModule.cpp

@@ -1743,7 +1743,7 @@ void IRGenModule::addLinkLibraries() {
         LinkLibrary{"objc", LibraryKind::Library, /*static=*/false});
 
   if (TargetInfo.HasSwiftSwiftDirectRuntimeLibrary &&
-      getOptions().EnableSwiftDirectRuntime)
+      getOptions().EnableSwiftDirectRetainRelease)
     registerLinkLibrary(LinkLibrary{"swiftSwiftDirectRuntime",
                                     LibraryKind::Library, /*static=*/true});