Allow a new syntax in a module requires-declaration:
requires ! feature
The purpose of this is to allow (for instance) the module map for /usr/include
to exclude <tgmath.h> and <complex.h> when building in C++ (these headers are
instead provided by the C++ standard library in this case, and the glibc C
<tgmath.h> header would otherwise try to include <complex.h>, resulting in a
module cycle).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193549 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/Modules.rst b/docs/Modules.rst
index bcb71c2..9fb4c77 100644
--- a/docs/Modules.rst
+++ b/docs/Modules.rst
@@ -320,9 +320,12 @@
``requires`` *feature-list*
*feature-list*:
- *identifier* (',' *identifier*)*
+ *feature* (',' *feature*)*
-The requirements clause allows specific modules or submodules to specify that they are only accessible with certain language dialects or on certain platforms. The feature list is a set of identifiers, defined below. If any of the features is not available in a given translation unit, that translation unit shall not import the module.
+ *feature*:
+ ``!``:sub:`opt` *identifier*
+
+The requirements clause allows specific modules or submodules to specify that they are only accessible with certain language dialects or on certain platforms. The feature list is a set of identifiers, defined below. If any of the features is not available in a given translation unit, that translation unit shall not import the module. The optional ``!`` indicates that a feature is incompatible with the module.
The following features are defined: