[ARM] Add 'fillValidCPUArchList' to ARM targets

This is a support change for a CFE change (https://reviews.llvm.org/D42978)
that allows march and -target-cpu to list the valid targets in a note. The changes
are limited to the ARM/AArch64, since this is the only target that gets the CPU
list from LLVM.

llvm-svn: 324623
diff --git a/llvm/lib/Support/TargetParser.cpp b/llvm/lib/Support/TargetParser.cpp
index 5f288ff..e38121d 100644
--- a/llvm/lib/Support/TargetParser.cpp
+++ b/llvm/lib/Support/TargetParser.cpp
@@ -689,6 +689,20 @@
   return ARM::ArchKind::INVALID;
 }
 
+void llvm::ARM::fillValidCPUArchList(SmallVectorImpl<StringRef> &Values) {
+  for (const CpuNames<ARM::ArchKind> &Arch : CPUNames) {
+    if (Arch.ArchID != ARM::ArchKind::INVALID)
+      Values.push_back(Arch.getName());
+  }
+}
+
+void llvm::AArch64::fillValidCPUArchList(SmallVectorImpl<StringRef> &Values) {
+  for (const CpuNames<AArch64::ArchKind> &Arch : AArch64CPUNames) {
+    if (Arch.ArchID != AArch64::ArchKind::INVALID)
+      Values.push_back(Arch.getName());
+  }
+}
+
 // ARM, Thumb, AArch64
 ARM::ISAKind ARM::parseArchISA(StringRef Arch) {
   return StringSwitch<ARM::ISAKind>(Arch)