<rdar://problem/10796651> Introduce configuration macros into module maps.

Configuration macros are macros that are intended to alter how a
module works, such that we need to build different module variants
for different values of these macros. A module can declare its
configuration macros, in which case we will complain if the definition
of a configation macro on the command line (or lack thereof) differs
from the current preprocessor state at the point where the module is
imported. This should eliminate some surprises when enabling modules,
because "#define CONFIG_MACRO ..." followed by "#include
<module/header.h>" would silently ignore the CONFIG_MACRO setting. At
least it will no longer be silent about it.

Configuration macros are eventually intended to help reduce the number
of module variants that need to be built. When the list of
configuration macros for a module is exhaustive, we only need to
consider the settings for those macros when building/finding the
module, which can help isolate modules for various project-specific -D
flags that should never affect how modules are build (but currently do).



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@177466 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 3 deletions

diff --git a/include/clang/Basic/Module.h b/include/clang/Basic/Module.h
index 5f081e0f56..2add58019f 100644
--- a/include/clang/Basic/Module.h
+++ b/include/clang/Basic/Module.h
@@ -119,7 +119,14 @@ public:
   /// \brief Whether, when inferring submodules, the inferr submodules should
   /// export all modules they import (e.g., the equivalent of "export *").
   unsigned InferExportWildcard : 1;
-  
+
+  /// \brief Whether the set of configuration macros is exhaustive.
+  ///
+  /// When the set of configuration macros is exhaustive, meaning
+  /// that no identifier not in this list should affect how the module is
+  /// built.
+  unsigned ConfigMacrosExhaustive : 1;
+
   /// \brief Describes the visibility of the various names within a
   /// particular module.
   enum NameVisibilityKind {
@@ -190,6 +197,10 @@ public:
   /// an entity from this module is used.
   llvm::SmallVector<LinkLibrary, 2> LinkLibraries;
 
+  /// \brief The set of "configuration macros", which are macros that
+  /// (intentionally) change how this module is built.
+  std::vector<std::string> ConfigMacros;
+
   /// \brief Construct a top-level module.
   explicit Module(StringRef Name, SourceLocation DefinitionLoc,
                   bool IsFramework)
@@ -197,7 +208,8 @@ public:
       IsAvailable(true), IsFromModuleFile(false), IsFramework(IsFramework), 
       IsExplicit(false), IsSystem(false),
       InferSubmodules(false), InferExplicitSubmodules(false),
-      InferExportWildcard(false), NameVisibility(Hidden) { }
+      InferExportWildcard(false), ConfigMacrosExhaustive(false),
+      NameVisibility(Hidden) { }
   
   /// \brief Construct a new module or submodule.
   Module(StringRef Name, SourceLocation DefinitionLoc, Module *Parent, 
@@ -328,7 +340,7 @@ public:
   ///
   /// \returns The submodule if found, or NULL otherwise.
   Module *findSubmodule(StringRef Name) const;
-  
+
   typedef std::vector<Module *>::iterator submodule_iterator;
   typedef std::vector<Module *>::const_iterator submodule_const_iterator;