[Triple] Add target triple support for CheriotRTOS. (llvm#155374)

For context, CheriotRTOS is a custom RTOS co-designed for the CHERIoT
CHERI-enabled RISCV32E platform. It uses a custom ABI and linkage model,
necesitating representing it in the target triple.

Author: resistor

llvm/include/llvm/TargetParser/Triple.h

@@ -245,7 +245,8 @@ class Triple {
     LiteOS,
     Serenity,
     Vulkan, // Vulkan SPIR-V
-    LastOSType = Vulkan
+    CheriotRTOS,
+    LastOSType = CheriotRTOS
   };
   enum EnvironmentType {
     UnknownEnvironment,

llvm/lib/TargetParser/Triple.cpp

@@ -329,6 +329,8 @@ StringRef Triple::getOSTypeName(OSType Kind) {
   case LiteOS: return "liteos";
   case XROS: return "xros";
   case Vulkan: return "vulkan";
+  case CheriotRTOS:
+    return "cheriotrtos";
   }
 
   llvm_unreachable("Invalid OSType");
@@ -687,49 +689,50 @@ static Triple::VendorType parseVendor(StringRef VendorName) {
 
 static Triple::OSType parseOS(StringRef OSName) {
   return StringSwitch<Triple::OSType>(OSName)
-    .StartsWith("darwin", Triple::Darwin)
-    .StartsWith("dragonfly", Triple::DragonFly)
-    .StartsWith("freebsd", Triple::FreeBSD)
-    .StartsWith("fuchsia", Triple::Fuchsia)
-    .StartsWith("ios", Triple::IOS)
-    .StartsWith("kfreebsd", Triple::KFreeBSD)
-    .StartsWith("linux", Triple::Linux)
-    .StartsWith("lv2", Triple::Lv2)
-    .StartsWith("macos", Triple::MacOSX)
-    .StartsWith("managarm", Triple::Managarm)
-    .StartsWith("netbsd", Triple::NetBSD)
-    .StartsWith("openbsd", Triple::OpenBSD)
-    .StartsWith("solaris", Triple::Solaris)
-    .StartsWith("uefi", Triple::UEFI)
-    .StartsWith("win32", Triple::Win32)
-    .StartsWith("windows", Triple::Win32)
-    .StartsWith("zos", Triple::ZOS)
-    .StartsWith("haiku", Triple::Haiku)
-    .StartsWith("rtems", Triple::RTEMS)
-    .StartsWith("aix", Triple::AIX)
-    .StartsWith("cuda", Triple::CUDA)
-    .StartsWith("nvcl", Triple::NVCL)
-    .StartsWith("amdhsa", Triple::AMDHSA)
-    .StartsWith("ps4", Triple::PS4)
-    .StartsWith("ps5", Triple::PS5)
-    .StartsWith("elfiamcu", Triple::ELFIAMCU)
-    .StartsWith("tvos", Triple::TvOS)
-    .StartsWith("watchos", Triple::WatchOS)
-    .StartsWith("bridgeos", Triple::BridgeOS)
-    .StartsWith("driverkit", Triple::DriverKit)
-    .StartsWith("xros", Triple::XROS)
-    .StartsWith("visionos", Triple::XROS)
-    .StartsWith("mesa3d", Triple::Mesa3D)
-    .StartsWith("amdpal", Triple::AMDPAL)
-    .StartsWith("hermit", Triple::HermitCore)
-    .StartsWith("hurd", Triple::Hurd)
-    .StartsWith("wasi", Triple::WASI)
-    .StartsWith("emscripten", Triple::Emscripten)
-    .StartsWith("shadermodel", Triple::ShaderModel)
-    .StartsWith("liteos", Triple::LiteOS)
-    .StartsWith("serenity", Triple::Serenity)
-    .StartsWith("vulkan", Triple::Vulkan)
-    .Default(Triple::UnknownOS);
+      .StartsWith("darwin", Triple::Darwin)
+      .StartsWith("dragonfly", Triple::DragonFly)
+      .StartsWith("freebsd", Triple::FreeBSD)
+      .StartsWith("fuchsia", Triple::Fuchsia)
+      .StartsWith("ios", Triple::IOS)
+      .StartsWith("kfreebsd", Triple::KFreeBSD)
+      .StartsWith("linux", Triple::Linux)
+      .StartsWith("lv2", Triple::Lv2)
+      .StartsWith("macos", Triple::MacOSX)
+      .StartsWith("managarm", Triple::Managarm)
+      .StartsWith("netbsd", Triple::NetBSD)
+      .StartsWith("openbsd", Triple::OpenBSD)
+      .StartsWith("solaris", Triple::Solaris)
+      .StartsWith("uefi", Triple::UEFI)
+      .StartsWith("win32", Triple::Win32)
+      .StartsWith("windows", Triple::Win32)
+      .StartsWith("zos", Triple::ZOS)
+      .StartsWith("haiku", Triple::Haiku)
+      .StartsWith("rtems", Triple::RTEMS)
+      .StartsWith("aix", Triple::AIX)
+      .StartsWith("cuda", Triple::CUDA)
+      .StartsWith("nvcl", Triple::NVCL)
+      .StartsWith("amdhsa", Triple::AMDHSA)
+      .StartsWith("ps4", Triple::PS4)
+      .StartsWith("ps5", Triple::PS5)
+      .StartsWith("elfiamcu", Triple::ELFIAMCU)
+      .StartsWith("tvos", Triple::TvOS)
+      .StartsWith("watchos", Triple::WatchOS)
+      .StartsWith("bridgeos", Triple::BridgeOS)
+      .StartsWith("driverkit", Triple::DriverKit)
+      .StartsWith("xros", Triple::XROS)
+      .StartsWith("visionos", Triple::XROS)
+      .StartsWith("mesa3d", Triple::Mesa3D)
+      .StartsWith("amdpal", Triple::AMDPAL)
+      .StartsWith("hermit", Triple::HermitCore)
+      .StartsWith("hurd", Triple::Hurd)
+      .StartsWith("wasi", Triple::WASI)
+      .StartsWith("emscripten", Triple::Emscripten)
+      .StartsWith("shadermodel", Triple::ShaderModel)
+      .StartsWith("liteos", Triple::LiteOS)
+      .StartsWith("serenity", Triple::Serenity)
+      .StartsWith("vulkan", Triple::Vulkan)
+      .StartsWith("cheriotrtos", Triple::CheriotRTOS)
+      .Default(Triple::UnknownOS);
 }
 
 static Triple::EnvironmentType parseEnvironment(StringRef EnvironmentName) {

llvm/unittests/TargetParser/TripleTest.cpp

@@ -1381,6 +1381,11 @@ TEST(TripleTest, ParsedIDs) {
 
   T = Triple("huh");
   EXPECT_EQ(Triple::UnknownArch, T.getArch());
+
+  T = Triple("riscv32-unknown-cheriotrtos");
+  EXPECT_EQ(Triple::riscv32, T.getArch());
+  EXPECT_EQ(Triple::UnknownVendor, T.getVendor());
+  EXPECT_EQ(Triple::CheriotRTOS, T.getOS());
 }
 
 static std::string Join(StringRef A, StringRef B, StringRef C) {