[PATCH] D108720: Effectively revert 33c3d8a916c / D33782

[Reid Kleckner via Phabricator via cfe-commits]

rnk created this revision.
rnk added reviewers: zero9178, mibintc, erichkeane.
rnk requested review of this revision.
Herald added a project: clang.

This change would treat the token `or` in system headers as an
identifier, and elsewhere as an operator. As reported in
llvm.org/pr42427, many users classify their third party library headers
as "system" headers to suppress warnings. There's no clean way to
separate Windows SDK headers from user headers.

Since D103773 <https://reviews.llvm.org/D103773>, clang-cl's default mode completely disables C++ operator
names. That means that query.h compiles out of the box without this hack
in the pre-processor. For users who are using /permissive-, they must
set the QUERY_H_RESTRICTION_PERMISSIVE macro to rename this problematic
`or` field.

By reverting this change, we get to a consistent state: C++ operator
names are either enabled or disabled globally. If that breaks
compilation because legacy code is using `or` as an identifier, the user
has flags to work around the problem (`/permissive` or
`/clang:-fno-operator-names`).

Fixes PR42427


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D108720

Files:
  clang/lib/Lex/Preprocessor.cpp
  clang/test/Headers/ms-cppoperkey.cpp
  clang/test/Headers/ms-cppoperkey1.cpp
  clang/test/Headers/ms-cppoperkey2.cpp


Index: clang/test/Headers/ms-cppoperkey2.cpp
===================================================================
--- clang/test/Headers/ms-cppoperkey2.cpp
+++ /dev/null
@@ -1,11 +0,0 @@
-// RUN: %clang_cc1  -triple x86_64-pc-win32 -fms-compatibility \
-// RUN:     -ffreestanding -fsyntax-only -Werror  %s -verify
-// RUN: %clang_cc1 \
-// RUN:     -ffreestanding -fsyntax-only -Werror  %s -verify
-// expected-no-diagnostics
-int bb ( int x)
-{
-  // In user code, treat operator keyword as operator keyword.
-  if ( x>1 or x<0) return 1;
-  else return 0;  
-}
Index: clang/test/Headers/ms-cppoperkey1.cpp
===================================================================
--- clang/test/Headers/ms-cppoperkey1.cpp
+++ /dev/null
@@ -1,27 +0,0 @@
-// RUN: %clang_cc1 \
-// RUN:     -fms-compatibility -x c++-cpp-output \
-// RUN:     -ffreestanding -fsyntax-only -Werror \
-// RUN:     %s -verify
-
-
-# 1 "t.cpp"
-# 1 "query.h" 1 3 4
-// MS header <query.h> uses operator keyword as field name.  
-// Compile without syntax errors.
-struct tagRESTRICTION
-  {
-   union _URes 
-     {
-       int or; // Note use of cpp operator token
-     } res;
-  };
-   ;
-
-int aa ( int x)
-{
-  // In system header code, treat operator keyword as identifier.
-  if ( // expected-note{{to match this '('}}
-    x>1 or x<0) return 1; // expected-error{{expected ')'}}
-  else return 0;  
-}
-
Index: clang/test/Headers/ms-cppoperkey.cpp
===================================================================
--- clang/test/Headers/ms-cppoperkey.cpp
+++ /dev/null
@@ -1,16 +0,0 @@
-// RUN: %clang_cc1 \
-// RUN:     -fms-compatibility -x c++-cpp-output \
-// RUN:     -ffreestanding -fsyntax-only -Werror \
-// RUN:     %s -verify
-// expected-no-diagnostics
-# 1 "t.cpp"
-# 1 "query.h" 1 3
-// MS header <query.h> uses operator keyword as field name.  
-// Compile without syntax errors.
-struct tagRESTRICTION
-  {
-   union _URes 
-     {
-       int or; // Note use of cpp operator token
-     } res;
-  };
Index: clang/lib/Lex/Preprocessor.cpp
===================================================================
--- clang/lib/Lex/Preprocessor.cpp
+++ clang/lib/Lex/Preprocessor.cpp
@@ -723,11 +723,7 @@
   // is cleaned to tok::identifier "B". After cleaning the token's length is
   // still 3 and the SourceLocation refers to the location of the backslash.
   Identifier.setIdentifierInfo(II);
-  if (getLangOpts().MSVCCompat && II->isCPlusPlusOperatorKeyword() &&
-      getSourceManager().isInSystemHeader(Identifier.getLocation()))
-    Identifier.setKind(tok::identifier);
-  else
-    Identifier.setKind(II->getTokenID());
+  Identifier.setKind(II->getTokenID());
 
   return II;
 }


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