Add a new Simulator entry for the target triple environment

[bob.wilson]

Summary

Apple's iOS, tvOS and watchOS simulator platforms have never been clearly distinguished in the target triples. Even though they are intended to behave similarly to the corresponding device platforms, they have separate SDKs and are really separate platforms from the compiler's perspective. Clang now defines a macro when building for one of these simulator platforms (r297866) but that relies on the very indirect mechanism of checking to see which option was used to specify the minimum deployment target. That is not so great. Swift would also like to distinguish these simulator platforms in a similar way, but unlike Clang, Swift does not use a separate option to specify the minimum deployment target -- it uses a -target option to specify the target triple directly, including the OS version number. Using a different target triple for the simulator platforms is a much more direct and obvious way to specify this. Putting the "simulator" in the environment component of the triple means the OS values can stay the same and existing code the looks at the OS field will not be affected.

[echristo]

No objections here.

-eric

[bob.wilson]

Thanks, Eric!
r316380

ADT/TripleTest.cpp

TEST(TripleTest, getOSVersion) {
   T.getMacOSXVersion(Major, Minor, Micro);
   EXPECT_EQ((unsigned)10, Major);
   EXPECT_EQ((unsigned)4, Minor);
   EXPECT_EQ((unsigned)0, Micro);
   T.getiOSVersion(Major, Minor, Micro);
   EXPECT_EQ((unsigned)7, Major);
   EXPECT_EQ((unsigned)0, Minor);
   EXPECT_EQ((unsigned)0, Micro);
+  EXPECT_FALSE(T.isSimulatorEnvironment());
+
+  T = Triple("x86_64-apple-ios10.3-simulator");
+  EXPECT_TRUE(T.isiOS());
+  T.getiOSVersion(Major, Minor, Micro);
+  EXPECT_EQ((unsigned)10, Major);
+  EXPECT_EQ((unsigned)3, Minor);
+  EXPECT_EQ((unsigned)0, Micro);
+  EXPECT_TRUE(T.isSimulatorEnvironment());
 }
 
 TEST(TripleTest, FileFormat) {
   EXPECT_EQ(Triple::ELF, Triple("i686-unknown-linux-gnu").getObjectFormat());
   EXPECT_EQ(Triple::ELF, Triple("i686-unknown-freebsd").getObjectFormat());
   EXPECT_EQ(Triple::ELF, Triple("i686-unknown-netbsd").getObjectFormat());
   EXPECT_EQ(Triple::ELF, Triple("i686--win32-elf").getObjectFormat());
   EXPECT_EQ(Triple::ELF, Triple("i686---elf").getObjectFormat());

Support/Triple.cpp

StringRef Triple::getEnvironmentTypeName(EnvironmentType Kind) {
   case MuslEABI: return "musleabi";
   case MuslEABIHF: return "musleabihf";
   case MSVC: return "msvc";
   case Itanium: return "itanium";
   case Cygnus: return "cygnus";
   case AMDOpenCL: return "amdopencl";
   case CoreCLR: return "coreclr";
   case OpenCL: return "opencl";
+  case Simulator: return "simulator";
   }
 
   llvm_unreachable("Invalid EnvironmentType!");
 }
 
 static Triple::ArchType parseBPFArch(StringRef ArchName) {
   if (ArchName.equals("bpf")) {
     if (sys::IsLittleEndianHost)
return StringSwitch<Triple::EnvironmentType>(EnvironmentName)
     .StartsWith("musleabi", Triple::MuslEABI)
     .StartsWith("musl", Triple::Musl)
     .StartsWith("msvc", Triple::MSVC)
     .StartsWith("itanium", Triple::Itanium)
     .StartsWith("cygnus", Triple::Cygnus)
     .StartsWith("amdopencl", Triple::AMDOpenCL)
     .StartsWith("coreclr", Triple::CoreCLR)
     .StartsWith("opencl", Triple::OpenCL)
+    .StartsWith("simulator", Triple::Simulator)
     .Default(Triple::UnknownEnvironment);
 }
 
 static Triple::ObjectFormatType parseFormat(StringRef EnvironmentName) {
   return StringSwitch<Triple::ObjectFormatType>(EnvironmentName)
     .EndsWith("coff", Triple::COFF)
     .EndsWith("elf", Triple::ELF)
     .EndsWith("macho", Triple::MachO)

llvm/ADT/Triple.h

enum EnvironmentType {
     MuslEABIHF,
 
     MSVC,
     Itanium,
     Cygnus,
     AMDOpenCL,
     CoreCLR,
     OpenCL,
-    LastEnvironmentType = OpenCL
+    Simulator,  // Simulator variants of other systems, e.g., Apple's iOS
+    LastEnvironmentType = Simulator
   };
   enum ObjectFormatType {
     UnknownObjectFormat,
 
     COFF,
     ELF,
     MachO,
     Wasm,
bool isWatchABI() const {
     return getSubArch() == Triple::ARMSubArch_v7k;
   }
 
   /// isOSDarwin - Is this a "Darwin" OS (OS X, iOS, or watchOS).
   bool isOSDarwin() const {
     return isMacOSX() || isiOS() || isWatchOS();
   }
 
+  bool isSimulatorEnvironment() const {
+    return getEnvironment() == Triple::Simulator;
+  }
+
   bool isOSNetBSD() const {
     return getOS() == Triple::NetBSD;
   }
 
   bool isOSOpenBSD() const {
     return getOS() == Triple::OpenBSD;
   }