Add MTIA and META to triple (#150236)

Ref:
https://ai.meta.com/blog/next-generation-meta-training-inference-accelerator-AI-MTIA/
This PR contains 
1. MTIA: Meta Training and Inference Accelerator as Environment.
2. Meta as the vendor.


### Testing 
Added a unittest for the relevant changes

### Reviewers
@clayborg , @jeffreytan81 , @Jlalond

Author: satyajanga

llvm/include/llvm/TargetParser/Triple.h

@@ -199,7 +199,8 @@ class Triple {
     SUSE,
     OpenEmbedded,
     Intel,
-    LastVendorType = Intel
+    Meta,
+    LastVendorType = Meta
   };
   enum OSType {
     UnknownOS,
@@ -307,8 +308,8 @@ class Triple {
     Mlibc,
 
     PAuthTest,
-
-    LastEnvironmentType = PAuthTest
+    MTIA,
+    LastEnvironmentType = MTIA
   };
   enum ObjectFormatType {
     UnknownObjectFormat,

llvm/lib/TargetParser/Triple.cpp

@@ -277,6 +277,8 @@ StringRef Triple::getVendorTypeName(VendorType Kind) {
   case PC: return "pc";
   case SCEI: return "scei";
   case SUSE: return "suse";
+  case Meta:
+    return "meta";
   }
 
   llvm_unreachable("Invalid VendorType!");
@@ -390,6 +392,8 @@ StringRef Triple::getEnvironmentTypeName(EnvironmentType Kind) {
   case OpenHOS: return "ohos";
   case PAuthTest:
     return "pauthtest";
+  case MTIA:
+    return "mtia";
   case LLVM:
     return "llvm";
   case Mlibc:
@@ -677,6 +681,7 @@ static Triple::VendorType parseVendor(StringRef VendorName) {
       .Case("suse", Triple::SUSE)
       .Case("oe", Triple::OpenEmbedded)
       .Case("intel", Triple::Intel)
+      .Case("meta", Triple::Meta)
       .Default(Triple::UnknownVendor);
 }
 
@@ -780,6 +785,7 @@ static Triple::EnvironmentType parseEnvironment(StringRef EnvironmentName) {
       .StartsWith("pauthtest", Triple::PAuthTest)
       .StartsWith("llvm", Triple::LLVM)
       .StartsWith("mlibc", Triple::Mlibc)
+      .StartsWith("mtia", Triple::MTIA)
       .Default(Triple::UnknownEnvironment);
 }
 

llvm/unittests/TargetParser/TripleTest.cpp

@@ -758,6 +758,12 @@ TEST(TripleTest, ParsedIDs) {
   EXPECT_EQ(Triple::UnknownOS, T.getOS());
   EXPECT_EQ(Triple::UnknownEnvironment, T.getEnvironment());
 
+  T = Triple("riscv64-meta-unknown-mtia");
+  EXPECT_EQ(Triple::riscv64, T.getArch());
+  EXPECT_EQ(Triple::Meta, T.getVendor());
+  EXPECT_EQ(Triple::UnknownOS, T.getOS());
+  EXPECT_EQ(Triple::MTIA, T.getEnvironment());
+
   T = Triple("riscv64-unknown-linux");
   EXPECT_EQ(Triple::riscv64, T.getArch());
   EXPECT_EQ(Triple::UnknownVendor, T.getVendor());