[semantic-arc] Use BaseModRef effects from LLVMSwift.def in LLVMSwiftAA instead of a switch.

Author: gottesmm

lib/LLVMPasses/LLVMSwiftAA.cpp

@@ -17,42 +17,28 @@
 #include "llvm/IR/Module.h"
 
 using namespace llvm;
-using swift::SwiftAAResult;
-using swift::SwiftAAWrapperPass;
+using namespace swift;
 
 //===----------------------------------------------------------------------===//
 //                           Alias Analysis Result
 //===----------------------------------------------------------------------===//
 
-llvm::ModRefInfo SwiftAAResult::getModRefInfo(llvm::ImmutableCallSite CS,
-                                              const llvm::MemoryLocation &Loc) {
-  // We know the mod-ref behavior of various runtime functions.
-  switch (classifyInstruction(*CS.getInstruction())) {
-  case RT_AllocObject:
-  case RT_NoMemoryAccessed:
-  case RT_Retain:
-  case RT_RetainUnowned:
-  case RT_CheckUnowned:
-  case RT_ObjCRetain:
-  case RT_BridgeRetain:
-  case RT_UnknownRetain:
-  case RT_RetainN:
-  case RT_UnknownRetainN:
-  case RT_BridgeRetainN:
-  case RT_FixLifetime:
-    // These entrypoints don't modify any compiler-visible state.
-    return MRI_NoModRef;
-  case RT_ReleaseN:
-  case RT_UnknownReleaseN:
-  case RT_BridgeReleaseN:
-  case RT_Release:
-  case RT_ObjCRelease:
-  case RT_BridgeRelease:
-  case RT_UnknownRelease:
-  case RT_Unknown:
-    break;
+static ModRefInfo getConservativeModRefForKind(const llvm::Instruction &I) {
+  switch (classifyInstruction(I)) {
+#define KIND(Name, MemBehavior) case RT_ ## Name: return MRI_ ## MemBehavior;
+#include "LLVMSwift.def"
   }
+}
+
+ModRefInfo SwiftAAResult::getModRefInfo(llvm::ImmutableCallSite CS,
+                                        const llvm::MemoryLocation &Loc) {
+  // We know at compile time that certain entry points do not modify any
+  // compiler-visible state ever. Quickly check if we have one of those
+  // instructions and return if so.
+  if (MRI_NoModRef == getConservativeModRefForKind(*CS.getInstruction()))
+    return MRI_NoModRef;
 
+  // Otherwise, delegate to the rest of the AA ModRefInfo machinery.
   return AAResultBase::getModRefInfo(CS, Loc);
 }