Pass.h/cpp - cleanup includes and forward declaration. NFC.

Remove unused BasicBlock forward declaration from Pass.h and Attributes/BasicBlock includes from Pass.cpp
Add BasicBlock forward declaration to UnifyFunctionExitNodes.h which was relying on Pass.h

llvm/include/llvm/Pass.h

@@ -34,7 +34,6 @@ namespace llvm {
 
 class AnalysisResolver;
 class AnalysisUsage;
-class BasicBlock;
 class Function;
 class ImmutablePass;
 class Module;

llvm/include/llvm/Transforms/Utils/UnifyFunctionExitNodes.h

@@ -22,6 +22,8 @@
 
 namespace llvm {
 
+class BasicBlock;
+
 struct UnifyFunctionExitNodes : public FunctionPass {
   BasicBlock *ReturnBlock = nullptr;
   BasicBlock *UnwindBlock = nullptr;

llvm/lib/IR/Pass.cpp

@@ -14,8 +14,6 @@
 
 #include "llvm/Pass.h"
 #include "llvm/Config/llvm-config.h"
-#include "llvm/IR/Attributes.h"
-#include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/Function.h"
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/LLVMContext.h"