[Apple Silicon] Baseline arm64 macOS at Swift 5.3 / macOS 10.16

Author: shahmishal

lib/AST/Availability.cpp

@@ -246,6 +246,9 @@ AvailabilityContext ASTContext::getSwift50Availability() {
     return AvailabilityContext::alwaysAvailable();
 
   if (target.isMacOSX()) {
+    if (target.isAArch64())
+      return AvailabilityContext::alwaysAvailable();
+
     return AvailabilityContext(
                             VersionRange::allGTE(llvm::VersionTuple(10,14,4)));
   } else if (target.isiOS()) {
@@ -274,6 +277,9 @@ AvailabilityContext ASTContext::getSwift51Availability() {
     return AvailabilityContext::alwaysAvailable();
 
   if (target.isMacOSX()) {
+    if (target.isAArch64())
+      return AvailabilityContext::alwaysAvailable();
+
     return AvailabilityContext(
                             VersionRange::allGTE(llvm::VersionTuple(10,15,0)));
   } else if (target.isiOS()) {
@@ -302,6 +308,9 @@ AvailabilityContext ASTContext::getSwift52Availability() {
     return AvailabilityContext::alwaysAvailable();
 
   if (target.isMacOSX() ) {
+    if (target.isAArch64())
+      return AvailabilityContext::alwaysAvailable();
+
     return AvailabilityContext(
         VersionRange::allGTE(llvm::VersionTuple(10, 99, 0)));
   } else if (target.isiOS()) {
@@ -322,6 +331,9 @@ AvailabilityContext ASTContext::getSwift53Availability() {
     return AvailabilityContext::alwaysAvailable();
 
   if (target.isMacOSX() ) {
+    if (target.isAArch64())
+      return AvailabilityContext::alwaysAvailable();
+
     return AvailabilityContext(
         VersionRange::allGTE(llvm::VersionTuple(10, 99, 0)));
   } else if (target.isiOS()) {

lib/Basic/Platform.cpp

@@ -387,6 +387,9 @@ swift::getSwiftRuntimeCompatibilityVersionForTarget(
   if (Triple.isMacOSX()) {
     Triple.getMacOSXVersion(Major, Minor, Micro);
     if (Major == 10) {
+      if (Triple.isAArch64() && Minor <= 16)
+        return llvm::VersionTuple(5, 3);
+
       if (Minor <= 14) {
         return llvm::VersionTuple(5, 0);
       } else if (Minor <= 15) {

lib/Driver/DarwinToolChains.cpp

@@ -602,6 +602,14 @@ toolchains::Darwin::addDeploymentTargetArgs(ArgStringList &Arguments,
       switch (getDarwinPlatformKind((triple))) {
       case DarwinPlatformKind::MacOS:
         triple.getMacOSXVersion(major, minor, micro);
+
+        // The first deployment of arm64 for macOS is version 10.16;
+        if (triple.isAArch64() && major <= 10 && minor < 16) {
+          major = 10;
+          minor = 16;
+          micro = 0;
+        }
+
         break;
       case DarwinPlatformKind::IPhoneOS:
       case DarwinPlatformKind::IPhoneOSSimulator:

test/Driver/linker.swift

@@ -106,6 +106,9 @@
 // RUN: %swiftc_driver -driver-print-jobs -target x86_64-apple-macosx10.9 -sdk %S/Inputs/MacOSX10.15.4.versioned.sdk %s 2>&1 | %FileCheck -check-prefix MACOS_10_15_4 %s
 // RUN: %swiftc_driver -driver-print-jobs -target x86_64-apple-macosx10.9 -sdk %S/Inputs/MacOSX10.15.sdk %s 2>&1 | %FileCheck -check-prefix MACOS_UNVERSIONED %s
 
+// Check arm64 macOS first deployment version adjustment.
+// RUN: %swiftc_driver -driver-print-jobs -target arm64-apple-macosx10.15.1 %s 2>&1 | %FileCheck -check-prefix ARM64E_MACOS_LINKER %s
+
 // MACOS_10_15: -platform_version macos 10.9.0 10.15.0
 // MACOS_10_15_4: -platform_version macos 10.9.0 10.15.4
 // MACOS_UNVERSIONED: -platform_version macos 10.9.0 0.0.0

test/IRGen/autolink-runtime-compatibility-arm64-macos.swift

@@ -0,0 +1,13 @@
+// REQUIRES: CPU=arm64,OS=macosx
+
+// Doesn't autolink compatibility library because target OS doesn't need it
+// RUN: %target-swift-frontend -target arm64-apple-macosx10.14  -emit-ir -parse-stdlib %s | %FileCheck -check-prefix=NO-FORCE-LOAD %s
+
+public func foo() {}
+
+// NO-FORCE-LOAD-NOT: FORCE_LOAD
+// NO-FORCE-LOAD-NOT: !{!"-lswiftCompatibility50"}
+// NO-FORCE-LOAD-NOT: !{!"-lswiftCompatibility51"}
+// NO-FORCE-LOAD-NOT: !{!"-lswiftCompatibility52"}
+// NO-FORCE-LOAD-NOT: !{!"-lswiftCompatibility53"}
+// NO-FORCE-LOAD-NOT: !{!"-lswiftCompatibilityDynamicReplacements"}