Remove StringMap::GetOrCreateValue in favor of StringMap::insert

Having two ways to do this doesn't seem terribly helpful and
consistently using the insert version (which we already has) seems like
it'll make the code easier to understand to anyone working with standard
data structures. (I also updated many references to the Entry's
key and value to use first() and second instead of getKey{Data,Length,}
and get/setValue - for similar consistency)

Also removes the GetOrCreateValue functions so there's less surface area
to StringMap to fix/improve/change/accommodate move semantics, etc.

llvm-svn: 222319
diff --git a/llvm/lib/IR/ValueSymbolTable.cpp b/llvm/lib/IR/ValueSymbolTable.cpp
index e9e979a..2b23f6d 100644
--- a/llvm/lib/IR/ValueSymbolTable.cpp
+++ b/llvm/lib/IR/ValueSymbolTable.cpp
@@ -56,11 +56,10 @@
     raw_svector_ostream(UniqueName) << ++LastUnique;
 
     // Try insert the vmap entry with this suffix.
-    ValueName &NewName = vmap.GetOrCreateValue(UniqueName);
-    if (!NewName.getValue()) {
+    auto IterBool = vmap.insert(std::make_pair(UniqueName, V));
+    if (IterBool.second) {
       // Newly inserted name.  Success!
-      NewName.setValue(V);
-      V->Name = &NewName;
+      V->Name = &*IterBool.first;
      //DEBUG(dbgs() << " Inserted value: " << UniqueName << ": " << *V << "\n");
       return;
     }
@@ -78,12 +77,11 @@
 /// auto-renames the name and returns that instead.
 ValueName *ValueSymbolTable::createValueName(StringRef Name, Value *V) {
   // In the common case, the name is not already in the symbol table.
-  ValueName &Entry = vmap.GetOrCreateValue(Name);
-  if (!Entry.getValue()) {
-    Entry.setValue(V);
+  auto IterBool = vmap.insert(std::make_pair(Name, V));
+  if (IterBool.second) {
     //DEBUG(dbgs() << " Inserted value: " << Entry.getKeyData() << ": "
     //           << *V << "\n");
-    return &Entry;
+    return &*IterBool.first;
   }
   
   // Otherwise, there is a naming conflict.  Rename this value.
@@ -95,12 +93,11 @@
     raw_svector_ostream(UniqueName) << ++LastUnique;
     
     // Try insert the vmap entry with this suffix.
-    ValueName &NewName = vmap.GetOrCreateValue(UniqueName);
-    if (!NewName.getValue()) {
-      // Newly inserted name.  Success!
-      NewName.setValue(V);
-     //DEBUG(dbgs() << " Inserted value: " << UniqueName << ": " << *V << "\n");
-      return &NewName;
+    auto IterBool = vmap.insert(std::make_pair(UniqueName, V));
+    if (IterBool.second) {
+      // DEBUG(dbgs() << " Inserted value: " << UniqueName << ": " << *V <<
+      //       "\n");
+      return &*IterBool.first;
     }
   }
 }