[Pass] Ensure we don't include PassSupport.h/PassAnalysisSupport.h directly

[RKSimon]

Summary

Both PassSupport.h and PassAnalysisSupport.h are only supposed to be included via Pass.h.

This patch fixes the case where PassRegistry.cpp was including PassSupport.h and adds #ifndef error checks to help ensure it doesn't happen again.

[thegameg]

There are still a bunch of other users of the headers in tree, but the error doesn't trigger since Pass.h gets included before. Is that worth changing as well?

[RKSimon]

In D78815#2002411, @thegameg wrote:

There are still a bunch of other users of the headers in tree, but the error doesn't trigger since Pass.h gets included before. Is that worth changing as well?

Sure, I'll take a look

[RKSimon]

Add check that PassSupport.h/PassAnalysisSupport.h aren't included again after Pass.h has been included.

Many of the additional file changes have implicit Pass.h includes but since the PassSupport.h/PassAnalysisSupport.h include was explicit I've added a Pass.h include.

[RKSimon]

llvm/include/llvm/PassAnalysisSupport.h

22

Technically these include guards are now redundant but I've kept them for clarity

[thegameg]

LGTM, thanks!

llvm/include/llvm/PassAnalysisSupport.h

 // This file is automatically #included by Pass.h, so:
 //
 //           NO .CPP FILES SHOULD INCLUDE THIS FILE DIRECTLY
 //
 // Instead, #include Pass.h
 //
 //===----------------------------------------------------------------------===//
 
+#ifndef LLVM_PASS_H
+#error "Do not include <PassAnalysisSupport.h>; include <Pass.h> instead"
+#endif 
+
 #ifndef LLVM_PASSANALYSISSUPPORT_H
 #define LLVM_PASSANALYSISSUPPORT_H
 
-#include "Pass.h"
 #include "llvm/ADT/SmallVector.h"
 #include <cassert>
 #include <utility>
 #include <vector>
 
 namespace llvm {
 
 class Function;

llvm/include/llvm/PassSupport.h

 //           NO .CPP FILES SHOULD INCLUDE THIS FILE DIRECTLY
 //
 // Instead, #include Pass.h.
 //
 // This file defines Pass registration code and classes used for it.
 //
 //===----------------------------------------------------------------------===//
 
+#ifndef LLVM_PASS_H
+#error "Do not include <PassSupport.h>; include <Pass.h> instead"
+#endif
+
 #ifndef LLVM_PASSSUPPORT_H
 #define LLVM_PASSSUPPORT_H
 
 #include "llvm/ADT/StringRef.h"
 #include "llvm/PassInfo.h"
 #include "llvm/PassRegistry.h"
 #include "llvm/Support/Threading.h"
 #include <functional>

llvm/lib/IR/PassRegistry.cpp

 //===- PassRegistry.cpp - Pass Registration Implementation ----------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
 // This file implements the PassRegistry, with which passes are registered on
 // initialization, and supports the PassManager in dependency resolution.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/PassRegistry.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/PassInfo.h"
-#include "llvm/PassSupport.h"
+#include "llvm/Pass.h"
 #include "llvm/Support/ManagedStatic.h"
 #include <cassert>
 #include <memory>
 #include <utility>
 
 using namespace llvm;
 
 // FIXME: We use ManagedStatic to erase the pass registrar on shutdown.