Commit 0f9cf42f authored by Zachary Henkel's avatar Zachary Henkel Committed by Reid Kleckner
Browse files

Allow /D flags absent during PCH creation under msvc-compat 

Summary:
Before this patch adding a new /D flag when compiling a source file that consumed a PCH with clang-cl would issue a diagnostic and then fail.  With the patch, the diagnostic is still issued but the definition is accepted.  This matches the msvc behavior.  The fuzzy-pch-msvc.c is a clone of the existing fuzzy-pch.c tests with some msvc specific rework.

msvc diagnostic:
  warning C4605: '/DBAR=int' specified on current command line, but was not specified when precompiled header was built

Output of the CHECK-BAR test prior to the code change:
  <built-in>(1,9): warning: definition of macro 'BAR' does not match definition in precompiled header [-Wclang-cl-pch]
  #define BAR int
          ^
  D:\repos\llvm\llvm-project\clang\test\PCH\fuzzy-pch-msvc.c(12,1): error: unknown type name 'BAR'
  BAR bar = 17;
  ^
  D:\repos\llvm\llvm-project\clang\test\PCH\fuzzy-pch-msvc.c(23,4): error: BAR was not defined
  #  error BAR was not defined
     ^
  1 warning and 2 errors generated.

Reviewers: rnk, thakis, hans, zturner

Subscribers: mikerice, aganea, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D72405
parent 40cd26c7

clang/lib/Lex/PPDirectives.cpp

+3 −1
Original line number Diff line number Diff line
@@ -2727,6 +2727,8 @@ void Preprocessor::HandleDefineDirective( 
                             /*Syntactic=*/LangOpts.MicrosoftExt))

      Diag(MI->getDefinitionLoc(), diag::warn_pp_macro_def_mismatch_with_pch)

          << MacroNameTok.getIdentifierInfo();

    // Issue the diagnostic but allow the change if msvc extensions are enabled

    if (!LangOpts.MicrosoftExt)

      return;

  }

clang/test/PCH/ms-pch-macro.c

0 → 100644
+39 −0
Original line number Diff line number Diff line 
// Test -D and -U interaction with a PCH when -fms-extensions is enabled.



// RUN: %clang_cc1 -DFOO %S/variables.h -emit-pch -o %t1.pch



// RUN: not %clang_cc1 -DFOO=blah -DBAR=int -include-pch %t1.pch -pch-through-header=%S/variables.h %s 2> %t.err

// RUN: FileCheck -check-prefix=CHECK-FOO %s < %t.err



// RUN: not %clang_cc1 -UFOO -DBAR=int -include-pch %t1.pch %s -pch-through-header=%S/variables.h 2> %t.err

// RUN: FileCheck -check-prefix=CHECK-NOFOO %s < %t.err



// RUN: %clang_cc1 -include-pch %t1.pch -DBAR=int -pch-through-header=%S/variables.h -verify %s 2> %t.err



// Enabling MS extensions should allow us to add BAR definitions.

// RUN: %clang_cc1 -fms-extensions -DFOO %S/variables.h -emit-pch -o %t1.pch

// RUN: %clang_cc1 -fms-extensions -include-pch %t1.pch -DBAR=int -pch-through-header=%S/variables.h -verify %s 2> %t.err



#include "variables.h"



BAR bar = 17;

#ifndef _MSC_EXTENSIONS

// expected-error@-2 {{unknown type name 'BAR'}}

#endif



#ifndef FOO

#  error FOO was not defined

#endif



#if FOO != 1

#  error FOO has the wrong definition

#endif



#if defined(_MSC_EXTENSIONS) && !defined(BAR)

#  error BAR was not defined

#endif



// CHECK-FOO: definition of macro 'FOO' differs between the precompiled header ('1') and the command line ('blah')

// CHECK-NOFOO: macro 'FOO' was defined in the precompiled header but undef'd on the command line



// expected-warning@1 {{definition of macro 'BAR' does not match definition in precompiled header}}