Refactor the code that erases sil functions into a new method, eraseFunction, and remember to clean the function table.

Swift SVN r11999

include/swift/SIL/SILModule.h

@@ -157,6 +157,12 @@ public:
     return Types.getTypeLowering(t);
   }
 
+  /// Erase a function from the module.
+  void eraseFunction(SILFunction *F) {
+    getFunctionList().erase(F);
+    FunctionTable.erase(F->getName());
+  }
+
   /// Construct a SIL module from an AST module.
   ///
   /// The module will be constructed in the Raw stage. The provided AST module

lib/SILPasses/SILCombine.cpp

@@ -786,7 +786,7 @@ bool tryToRemoveFunction(SILFunction *F) {
     return false;
 
   DEBUG(llvm::dbgs() << "SC: Erasing:" << F->getName() << "\n");
-  F->getModule().getFunctionList().erase(F);
+  F->getModule().eraseFunction(F);
   NumDeadFunc++;
   return true;
 }