[clang][darwin] Add support for the -mtargetos= option to the driver

clang/include/clang/Basic/DiagnosticDriverKinds.td

@@ -235,6 +235,7 @@ def warn_invalid_ios_deployment_target : Warning<
   DefaultError;
 def err_invalid_macos_32bit_deployment_target : Error<
   "32-bit targets are not supported when building for Mac Catalyst">;
+def err_drv_invalid_os_in_arg : Error<"invalid OS value '%0' in '%1'">;
 def err_drv_conflicting_deployment_targets : Error<
   "conflicting deployment targets, both '%0' and '%1' are present in environment">;
 def err_arc_unsupported_on_runtime : Error<

clang/include/clang/Driver/Options.td

@@ -3193,6 +3193,8 @@ def meabi : Separate<["-"], "meabi">, Group<m_Group>, Flags<[CC1Option]>,
   MarshallingInfoEnum<TargetOpts<"EABIVersion">, "Default">,
   NormalizedValuesScope<"llvm::EABI">,
   NormalizedValues<["Default", "EABI4", "EABI5", "GNU"]>;
+def mtargetos_EQ : Joined<["-"], "mtargetos=">, Group<m_Group>,
+  HelpText<"Set the deployment target to be the specified OS and OS version">;
 
 def mno_constant_cfstrings : Flag<["-"], "mno-constant-cfstrings">, Group<m_Group>;
 def mno_global_merge : Flag<["-"], "mno-global-merge">, Group<m_Group>, Flags<[CC1Option]>,

clang/lib/Driver/ToolChains/Darwin.cpp

@@ -1418,6 +1418,8 @@ struct DarwinPlatform {
   enum SourceKind {
     /// The OS was specified using the -target argument.
     TargetArg,
+    /// The OS was specified using the -mtargetos= argument.
+    MTargetOSArg,
     /// The OS was specified using the -m<os>-version-min argument.
     OSVersionArg,
     /// The OS was specified using the OS_DEPLOYMENT_TARGET environment.
@@ -1469,7 +1471,8 @@ struct DarwinPlatform {
   void addOSVersionMinArgument(DerivedArgList &Args, const OptTable &Opts) {
     if (Argument)
       return;
-    assert(Kind != TargetArg && Kind != OSVersionArg && "Invalid kind");
+    assert(Kind != TargetArg && Kind != MTargetOSArg && Kind != OSVersionArg &&
+           "Invalid kind");
     options::ID Opt;
     switch (Platform) {
     case DarwinPlatformKind::MacOS:
@@ -1494,6 +1497,7 @@ struct DarwinPlatform {
   std::string getAsString(DerivedArgList &Args, const OptTable &Opts) {
     switch (Kind) {
     case TargetArg:
+    case MTargetOSArg:
     case OSVersionArg:
     case InferredFromSDK:
     case InferredFromArch:
@@ -1505,40 +1509,54 @@ struct DarwinPlatform {
     llvm_unreachable("Unsupported Darwin Source Kind");
   }
 
-  static DarwinPlatform
-  createFromTarget(const llvm::Triple &TT, StringRef OSVersion, Arg *A,
-                   const Optional<DarwinSDKInfo> &SDKInfo) {
-    DarwinPlatform Result(TargetArg, getPlatformFromOS(TT.getOS()), OSVersion,
-                          A);
-    unsigned Major, Minor, Micro;
-    TT.getOSVersion(Major, Minor, Micro);
-    if (Major == 0)
-      Result.HasOSVersion = false;
-
-    switch (TT.getEnvironment()) {
+  void setEnvironment(llvm::Triple::EnvironmentType EnvType,
+                      const VersionTuple &OSVersion,
+                      const Optional<DarwinSDKInfo> &SDKInfo) {
+    switch (EnvType) {
     case llvm::Triple::Simulator:
-      Result.Environment = DarwinEnvironmentKind::Simulator;
+      Environment = DarwinEnvironmentKind::Simulator;
       break;
     case llvm::Triple::MacABI: {
+      Environment = DarwinEnvironmentKind::MacCatalyst;
       // The minimum native macOS target for MacCatalyst is macOS 10.15.
-      auto NativeTargetVersion = VersionTuple(10, 15);
-      if (Result.HasOSVersion && SDKInfo) {
+      NativeTargetVersion = VersionTuple(10, 15);
+      if (HasOSVersion && SDKInfo) {
         if (const auto *MacCatalystToMacOSMapping = SDKInfo->getVersionMapping(
                 DarwinSDKInfo::OSEnvPair::macCatalystToMacOSPair())) {
           if (auto MacOSVersion = MacCatalystToMacOSMapping->map(
-                  VersionTuple(Major, Minor, Micro), NativeTargetVersion,
-                  None)) {
+                  OSVersion, NativeTargetVersion, None)) {
             NativeTargetVersion = *MacOSVersion;
           }
         }
       }
-      Result.Environment = DarwinEnvironmentKind::MacCatalyst;
-      Result.NativeTargetVersion = NativeTargetVersion;
       break;
     }
     default:
       break;
     }
+  }
+
+  static DarwinPlatform
+  createFromTarget(const llvm::Triple &TT, StringRef OSVersion, Arg *A,
+                   const Optional<DarwinSDKInfo> &SDKInfo) {
+    DarwinPlatform Result(TargetArg, getPlatformFromOS(TT.getOS()), OSVersion,
+                          A);
+    unsigned Major, Minor, Micro;
+    TT.getOSVersion(Major, Minor, Micro);
+    if (Major == 0)
+      Result.HasOSVersion = false;
+    Result.setEnvironment(TT.getEnvironment(),
+                          VersionTuple(Major, Minor, Micro), SDKInfo);
+    return Result;
+  }
+  static DarwinPlatform
+  createFromMTargetOS(llvm::Triple::OSType OS, VersionTuple OSVersion,
+                      llvm::Triple::EnvironmentType Environment, Arg *A,
+                      const Optional<DarwinSDKInfo> &SDKInfo) {
+    DarwinPlatform Result(MTargetOSArg, getPlatformFromOS(OS),
+                          OSVersion.getAsString(), A);
+    Result.InferSimulatorFromArch = false;
+    Result.setEnvironment(Environment, OSVersion, SDKInfo);
     return Result;
   }
   static DarwinPlatform createOSVersionArg(DarwinPlatformKind Platform,
@@ -1852,6 +1870,39 @@ Optional<DarwinPlatform> getDeploymentTargetFromTargetArg(
       Triple, OSVersion, Args.getLastArg(options::OPT_target), SDKInfo);
 }
 
+/// Returns the deployment target that's specified using the -mtargetos option.
+Optional<DarwinPlatform>
+getDeploymentTargetFromMTargetOSArg(DerivedArgList &Args,
+                                    const Driver &TheDriver,
+                                    const Optional<DarwinSDKInfo> &SDKInfo) {
+  auto *A = Args.getLastArg(options::OPT_mtargetos_EQ);
+  if (!A)
+    return None;
+  llvm::Triple TT(llvm::Twine("unknown-apple-") + A->getValue());
+  switch (TT.getOS()) {
+  case llvm::Triple::MacOSX:
+  case llvm::Triple::IOS:
+  case llvm::Triple::TvOS:
+  case llvm::Triple::WatchOS:
+    break;
+  default:
+    TheDriver.Diag(diag::err_drv_invalid_os_in_arg)
+        << TT.getOSName() << A->getAsString(Args);
+    return None;
+  }
+
+  unsigned Major, Minor, Micro;
+  TT.getOSVersion(Major, Minor, Micro);
+  if (!Major) {
+    TheDriver.Diag(diag::err_drv_invalid_version_number)
+        << A->getAsString(Args);
+    return None;
+  }
+  return DarwinPlatform::createFromMTargetOS(TT.getOS(),
+                                             VersionTuple(Major, Minor, Micro),
+                                             TT.getEnvironment(), A, SDKInfo);
+}
+
 Optional<DarwinSDKInfo> parseSDKSettings(llvm::vfs::FileSystem &VFS,
                                          const ArgList &Args,
                                          const Driver &TheDriver) {
@@ -1900,6 +1951,13 @@ void Darwin::AddDeploymentTarget(DerivedArgList &Args) const {
   Optional<DarwinPlatform> OSTarget =
       getDeploymentTargetFromTargetArg(Args, getTriple(), getDriver(), SDKInfo);
   if (OSTarget) {
+    // Disallow mixing -target and -mtargetos=.
+    if (const auto *MTargetOSArg = Args.getLastArg(options::OPT_mtargetos_EQ)) {
+      std::string TargetArgStr = OSTarget->getAsString(Args, Opts);
+      std::string MTargetOSArgStr = MTargetOSArg->getAsString(Args);
+      getDriver().Diag(diag::err_drv_cannot_mix_options)
+          << TargetArgStr << MTargetOSArgStr;
+    }
     Optional<DarwinPlatform> OSVersionArgTarget =
         getDeploymentTargetFromOSVersionArg(Args, getDriver());
     if (OSVersionArgTarget) {
@@ -1931,6 +1989,18 @@ void Darwin::AddDeploymentTarget(DerivedArgList &Args) const {
         }
       }
     }
+  } else if ((OSTarget = getDeploymentTargetFromMTargetOSArg(Args, getDriver(),
+                                                             SDKInfo))) {
+    // The OS target can be specified using the -mtargetos= argument.
+    // Disallow mixing -mtargetos= and -m<os>version-min=.
+    Optional<DarwinPlatform> OSVersionArgTarget =
+        getDeploymentTargetFromOSVersionArg(Args, getDriver());
+    if (OSVersionArgTarget) {
+      std::string MTargetOSArgStr = OSTarget->getAsString(Args, Opts);
+      std::string OSVersionArgStr = OSVersionArgTarget->getAsString(Args, Opts);
+      getDriver().Diag(diag::err_drv_cannot_mix_options)
+          << MTargetOSArgStr << OSVersionArgStr;
+    }
   } else {
     // The OS target can be specified using the -m<os>version-min argument.
     OSTarget = getDeploymentTargetFromOSVersionArg(Args, getDriver());

clang/test/Driver/mtargetos-darwin.c

@@ -0,0 +1,26 @@
+// RUN: %clang -mtargetos=macos11 -arch arm64 -arch x86_64 -c %s -o %t.o -### 2>&1 | FileCheck --check-prefix=MACOS %s
+// RUN: %clang -mtargetos=ios14 -arch arm64 -c %s -o %t.o -### 2>&1 | FileCheck --check-prefix=IOS %s
+// RUN: %clang -mtargetos=ios14-simulator -arch arm64 -c %s -o %t.o -### 2>&1 | FileCheck --check-prefix=IOS_SIM %s
+// RUN: %clang -mtargetos=ios14-macabi -arch arm64 -c %s -o %t.o -### 2>&1 | FileCheck --check-prefix=MACCATALYST %s
+// RUN: %clang -mtargetos=tvos14 -arch arm64 -c %s -o %t.o -### 2>&1 | FileCheck --check-prefix=TVOS %s
+// RUN: %clang -mtargetos=watchos7.1 -arch arm64 -c %s -o %t.o -### 2>&1 | FileCheck --check-prefix=WATCHOS %s
+
+// RUN: %clang -target arm64-apple-ios14 -mtargetos=ios14 -arch arm64 -c %s -o %t.o -### 2>&1 | FileCheck --check-prefix=NOMIX1 %s
+// RUN: %clang -mtargetos=ios14 -arch arm64 -miphoneos-version-min=14 -c %s -o %t.o -### 2>&1 | FileCheck --check-prefix=NOMIX2 %s
+// RUN: %clang -mtargetos=darwin20 -arch arm64 -c %s -o %t.o -### 2>&1 | FileCheck --check-prefix=INVALIDOS %s
+// RUN: %clang -mtargetos=ios -arch arm64 -c %s -o %t.o -### 2>&1 | FileCheck --check-prefix=NOVERSION %s
+
+// REQUIRES: darwin
+
+// MACOS: "-cc1" "-triple" "arm64-apple-macosx11.0.0"
+// MACOS-NEXT: "-cc1" "-triple" "x86_64-apple-macosx11.0.0"
+// IOS: "-cc1" "-triple" "arm64-apple-ios14.0.0"
+// IOS_SIM: "-cc1" "-triple" "arm64-apple-ios14.0.0-simulator"
+// MACCATALYST: "-cc1" "-triple" "arm64-apple-ios14.0.0-macabi"
+// TVOS: "-cc1" "-triple" "arm64-apple-tvos14.0.0"
+// WATCHOS: "-cc1" "-triple" "arm64-apple-watchos7.1.0"
+
+// NOMIX1: error: cannot specify '-mtargetos=ios14' along with '-target arm64-apple-ios14'
+// NOMIX2: error: cannot specify '-miphoneos-version-min=14' along with '-mtargetos=ios14'
+// INVALIDOS: error: invalid OS value 'darwin20' in '-mtargetos=darwin20'
+// NOVERSION: error: invalid version number in '-mtargetos=ios'