ARM target now also recognize triplets like thumbv6-apple-darwin and set thumb mode and arch subversion. Eventually thumb triplets will go way and replaced with function notes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@66435 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMSubtarget.cpp b/lib/Target/ARM/ARMSubtarget.cpp
index f5a1840..2415a85 100644
--- a/lib/Target/ARM/ARMSubtarget.cpp
+++ b/lib/Target/ARM/ARMSubtarget.cpp
@@ -36,23 +36,30 @@
   // if one cannot be determined, to true.
   const std::string& TT = M.getTargetTriple();
   unsigned Len = TT.length();
-  if (Len >= 5) {
-    if (TT.substr(0, 4) == "armv") {
-      unsigned SubVer = TT[4];
-      if (SubVer > '4' && SubVer <= '9') {
-        if (SubVer >= '6')
-          ARMArchVersion = V6;
-        else if (SubVer == '5') {
-          ARMArchVersion = V5T;
-          if (Len >= 7 && TT[5] == 't' && TT[6] == 'e')
-            ARMArchVersion = V5TE;
-        }
+  unsigned Idx = 0;
+  if (Len >= 5 && TT.substr(0, 4) == "armv")
+    Idx = 4;
+  else if (Len >= 6 && TT.substr(0, 6) == "thumb") {
+    IsThumb = true;
+    if (Len >= 7 && TT[5] == 'v')
+      Idx = 6;
+  }
+  if (Idx) {
+    unsigned SubVer = TT[Idx];
+    if (SubVer > '4' && SubVer <= '9') {
+      if (SubVer >= '6')
+        ARMArchVersion = V6;
+      else if (SubVer == '5') {
+        ARMArchVersion = V5T;
+        if (Len >= Idx+3 && TT[Idx+1] == 't' && TT[Idx+2] == 'e')
+          ARMArchVersion = V5TE;
       }
     }
   }
 
-  if (Len > 5) {
+  if (Len >= 10) {
     if (TT.find("-darwin") != std::string::npos)
+      // arm-darwin
       TargetType = isDarwin;
   } else if (TT.empty()) {
 #if defined(__APPLE__)