[ORC] Rename VSO to JITDylib.

VSO was a little close to VDSO (an acronym on Linux for Virtual Dynamic Shared
Object) for comfort. It also risks giving the impression that instances of this
class could be shared between ExecutionSessions, which they can not.

JITDylib seems moderately less confusing, while still hinting at how this
class is intended to be used, i.e. as a JIT-compiled stand-in for a dynamic
library (code that would have been a dynamic library if you had wanted to
compile it ahead of time).

llvm-svn: 340084
diff --git a/llvm/lib/ExecutionEngine/Orc/ExecutionUtils.cpp b/llvm/lib/ExecutionEngine/Orc/ExecutionUtils.cpp
index 6157677..bb32b3d 100644
--- a/llvm/lib/ExecutionEngine/Orc/ExecutionUtils.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/ExecutionUtils.cpp
@@ -131,7 +131,7 @@
     return;
 
   MangleAndInterner Mangle(
-      V.getExecutionSession(),
+      JD.getExecutionSession(),
       (*CtorDtors.begin()).Func->getParent()->getDataLayout());
 
   for (const auto &CtorDtor : CtorDtors) {
@@ -161,7 +161,7 @@
     }
   }
 
-  if (auto CtorDtorMap = lookup({&V}, std::move(Names))) {
+  if (auto CtorDtorMap = lookup({&JD}, std::move(Names))) {
     for (auto &KV : CtorDtorsByPriority) {
       for (auto &Name : KV.second) {
         assert(CtorDtorMap->count(Name) && "No entry for Name");
@@ -195,7 +195,8 @@
   return 0;
 }
 
-Error LocalCXXRuntimeOverrides2::enable(VSO &V, MangleAndInterner &Mangle) {
+Error LocalCXXRuntimeOverrides2::enable(JITDylib &JD,
+                                        MangleAndInterner &Mangle) {
   SymbolMap RuntimeInterposes(
       {{Mangle("__dso_handle"),
         JITEvaluatedSymbol(toTargetAddress(&DSOHandleOverride),
@@ -204,7 +205,7 @@
         JITEvaluatedSymbol(toTargetAddress(&CXAAtExitOverride),
                            JITSymbolFlags::Exported)}});
 
-  return V.define(absoluteSymbols(std::move(RuntimeInterposes)));
+  return JD.define(absoluteSymbols(std::move(RuntimeInterposes)));
 }
 
 DynamicLibraryFallbackGenerator::DynamicLibraryFallbackGenerator(
@@ -213,7 +214,7 @@
       GlobalPrefix(DL.getGlobalPrefix()) {}
 
 SymbolNameSet DynamicLibraryFallbackGenerator::
-operator()(VSO &V, const SymbolNameSet &Names) {
+operator()(JITDylib &JD, const SymbolNameSet &Names) {
   orc::SymbolNameSet Added;
   orc::SymbolMap NewSymbols;
 
@@ -235,11 +236,11 @@
     }
   }
 
-  // Add any new symbols to V. Since the fallback generator is only called for
+  // Add any new symbols to JD. Since the fallback generator is only called for
   // symbols that are not already defined, this will never trigger a duplicate
   // definition error, so we can wrap this call in a 'cantFail'.
   if (!NewSymbols.empty())
-    cantFail(V.define(absoluteSymbols(std::move(NewSymbols))));
+    cantFail(JD.define(absoluteSymbols(std::move(NewSymbols))));
 
   return Added;
 }