Add arm64_32 support for Swift

Commit the platform definition and build script work necessary to
cross-compile for arm64_32.

arm64_32 is a variant of AARCH64 that supports an ILP32 architecture.

Author: CodaFi

benchmark/cmake/modules/AddSwiftBenchmarkSuite.cmake

@@ -108,7 +108,7 @@ macro(configure_sdks_darwin)
   set(macosx_arch "x86_64" "arm64")
   set(iphoneos_arch "arm64" "arm64e" "armv7")
   set(appletvos_arch "arm64")
-  set(watchos_arch "armv7k")
+  set(watchos_arch "armv7k" "arm64_32")
 
   set(macosx_ver "10.9")
   set(iphoneos_ver "8.0")

cmake/modules/DarwinSDKs.cmake

@@ -12,7 +12,7 @@ endif()
 
 set(SUPPORTED_TVOS_ARCHS "arm64")
 set(SUPPORTED_TVOS_SIMULATOR_ARCHS "x86_64;arm64")
-set(SUPPORTED_WATCHOS_ARCHS "armv7k")
+set(SUPPORTED_WATCHOS_ARCHS "armv7k;arm64_32")
 set(SUPPORTED_WATCHOS_SIMULATOR_ARCHS "i386;x86_64;arm64")
 set(SUPPORTED_OSX_ARCHS "x86_64;arm64;arm64e")
 

cmake/modules/SwiftSetIfArchBitness.cmake

@@ -12,6 +12,7 @@ function(set_if_arch_bitness var_name)
      "${SIA_ARCH}" STREQUAL "armv6" OR
      "${SIA_ARCH}" STREQUAL "armv7" OR
      "${SIA_ARCH}" STREQUAL "armv7k" OR
+     "${SIA_ARCH}" STREQUAL "arm64_32" OR
      "${SIA_ARCH}" STREQUAL "armv7s" OR
      "${SIA_ARCH}" STREQUAL "wasm32")
     set("${var_name}" "${SIA_CASE_32_BIT}" PARENT_SCOPE)

lib/Basic/LangOptions.cpp

@@ -58,6 +58,7 @@ static const SupportedConditionalValue SupportedConditionalCompilationOSs[] = {
 static const SupportedConditionalValue SupportedConditionalCompilationArches[] = {
   "arm",
   "arm64",
+  "arm64_32",
   "i386",
   "x86_64",
   "powerpc64",
@@ -303,7 +304,12 @@ std::pair<bool, bool> LangOptions::setTarget(llvm::Triple triple) {
     addPlatformConditionValue(PlatformConditionKind::Arch, "arm");
     break;
   case llvm::Triple::ArchType::aarch64:
-    addPlatformConditionValue(PlatformConditionKind::Arch, "arm64");
+  case llvm::Triple::ArchType::aarch64_32:
+    if (Target.getArchName() == "arm64_32") {
+      addPlatformConditionValue(PlatformConditionKind::Arch, "arm64_32");
+    } else {
+      addPlatformConditionValue(PlatformConditionKind::Arch, "arm64");
+    }
     break;
   case llvm::Triple::ArchType::ppc64:
     addPlatformConditionValue(PlatformConditionKind::Arch, "powerpc64");
@@ -336,6 +342,7 @@ std::pair<bool, bool> LangOptions::setTarget(llvm::Triple triple) {
   case llvm::Triple::ArchType::arm:
   case llvm::Triple::ArchType::thumb:
   case llvm::Triple::ArchType::aarch64:
+  case llvm::Triple::ArchType::aarch64_32:
   case llvm::Triple::ArchType::ppc64le:
   case llvm::Triple::ArchType::wasm32:
   case llvm::Triple::ArchType::x86:

lib/Basic/Platform.cpp

@@ -262,6 +262,7 @@ getArchForAppleTargetSpecificModuleTriple(const llvm::Triple &triple) {
   //          .Case ("armv7s", "armv7s")
   //          .Case ("armv7k", "armv7k")
   //          .Case ("armv7", "armv7")
+  //          .Case ("arm64_32", "arm64_32")
   //          .Case ("arm64e", "arm64e")
               .Default(tripleArchName);
 }

lib/ClangImporter/ClangImporter.cpp

@@ -635,6 +635,7 @@ importer::getNormalInvocationArguments(
         invocationArgStrs.insert(invocationArgStrs.end(), {"-D_ARM_"});
         break;
       case llvm::Triple::aarch64:
+      case llvm::Triple::aarch64_32:
         invocationArgStrs.insert(invocationArgStrs.end(), {"-D_ARM64_"});
         break;
       case llvm::Triple::x86:
@@ -765,6 +766,7 @@ importer::addCommonInvocationArguments(
              (triple.isiOS() || triple.isWatchOS()))
       invocationArgStrs.push_back("-mcpu=apple-a12");
     else if (triple.getArch() == llvm::Triple::aarch64 ||
+             triple.getArch() == llvm::Triple::aarch64_32 ||
              triple.getArch() == llvm::Triple::aarch64_be) {
       invocationArgStrs.push_back("-mcpu=apple-a7");
     }

lib/Driver/ToolChains.cpp

@@ -169,7 +169,8 @@ void ToolChain::addCommonFrontendArgs(const OutputInfo &OI,
   }
 
   // Enable address top-byte ignored in the ARM64 backend.
-  if (Triple.getArch() == llvm::Triple::aarch64) {
+  if (Triple.getArch() == llvm::Triple::aarch64 ||
+      Triple.getArch() == llvm::Triple::aarch64_32) {
     arguments.push_back("-Xllvm");
     arguments.push_back("-aarch64-use-tbi");
   }
@@ -968,7 +969,8 @@ ToolChain::constructInvocation(const BackendJobAction &job,
   Arguments.push_back(context.Args.MakeArgString(getTriple().str()));
 
   // Enable address top-byte ignored in the ARM64 backend.
-  if (getTriple().getArch() == llvm::Triple::aarch64) {
+  if (getTriple().getArch() == llvm::Triple::aarch64 ||
+      getTriple().getArch() == llvm::Triple::aarch64_32) {
     Arguments.push_back("-Xllvm");
     Arguments.push_back("-aarch64-use-tbi");
   }

lib/Driver/UnixToolChains.cpp

@@ -88,6 +88,7 @@ std::string toolchains::GenericUnix::getDefaultLinker() const {
   switch (getTriple().getArch()) {
   case llvm::Triple::arm:
   case llvm::Triple::aarch64:
+  case llvm::Triple::aarch64_32:
   case llvm::Triple::armeb:
   case llvm::Triple::thumb:
   case llvm::Triple::thumbeb:

lib/IRGen/GenType.cpp

@@ -1359,6 +1359,7 @@ static llvm::StringLiteral platformsWithLegacyLayouts[][2] = {
   {"iphonesimulator", "x86_64"},
   {"macosx", "x86_64"},
   {"watchos", "armv7k"},
+  {"watchos", "arm64_32"},
   {"watchsimulator", "i386"}
 };
 

lib/IRGen/SwiftTargetInfo.cpp

@@ -64,6 +64,24 @@ static void configureARM64(IRGenModule &IGM, const llvm::Triple &triple,
   target.UsableSwiftAsyncContextAddrIntrinsic = true;
 }
 
+/// Configures target-specific information for arm64_32 platforms.
+static void configureARM64_32(IRGenModule &IGM, const llvm::Triple &triple,
+                              SwiftTargetInfo &target) {
+  setToMask(target.PointerSpareBits, 32,
+            SWIFT_ABI_ARM_SWIFT_SPARE_BITS_MASK);
+
+  // arm64_32 has no special objc_msgSend variants, not even stret.
+  target.ObjCUseStret = false;
+
+  // arm64_32 requires marker assembly for objc_retainAutoreleasedReturnValue.
+  target.ObjCRetainAutoreleasedReturnValueMarker =
+    "mov\tfp, fp\t\t// marker for objc_retainAutoreleaseReturnValue";
+
+  setToMask(target.IsObjCPointerBit, 32, SWIFT_ABI_ARM_IS_OBJC_BIT);
+
+  target.ObjCHasOpaqueISAs = true;
+}
+
 /// Configures target-specific information for x86-64 platforms.
 static void configureX86_64(IRGenModule &IGM, const llvm::Triple &triple,
                             SwiftTargetInfo &target) {
@@ -196,7 +214,11 @@ SwiftTargetInfo SwiftTargetInfo::get(IRGenModule &IGM) {
     break;
 
   case llvm::Triple::aarch64:
-    configureARM64(IGM, triple, target);
+  case llvm::Triple::aarch64_32:
+    if (triple.getArchName() == "arm64_32")
+      configureARM64_32(IGM, triple, target);
+    else
+      configureARM64(IGM, triple, target);
     break;
 
   case llvm::Triple::ppc64: