r193815 - Clang modules: collect exports recursively

[Richard Smith]

Please add a testcase!


On Thu, Oct 31, 2013 at 3:24 PM, Dmitri Gribenko <gribozavr at gmail.com>wrote:

> Author: gribozavr
> Date: Thu Oct 31 17:24:10 2013
> New Revision: 193815
>
> URL: http://llvm.org/viewvc/llvm-project?rev=193815&view=rev
> Log:
> Clang modules: collect exports recursively
>
> This change makes Module::buildVisibleModulesCache() collect exported
> modules
> recursively.
>
> While computing a set of exports, getExportedModules() iterates over the
> set of
> imported modules and filters it.  But it does not consider the set of
> exports
> of those modules -- it is the responsibility of the caller to do this.
>
> Here is a certain instance of this issue.  Module::isModuleVisible says
> that
> CoreFoundation.CFArray submodule is not visible from Cocoa.  Why?
>
> - Cocoa imports Foundation.
> - Foundation has an export restriction: "export *".
> - Foundation imports CoreFoundation.  (Just the top-level module.)
> - CoreFoundation exports CoreFoundation.CFArray.
>
> To decide which modules are visible from Cocoa, we collect all exported
> modules
> from immediate imports in Cocoa:
>
> > visibleModulesFro(Cocoa) = exported(Foundation) + exported(CoreData) +
> exported(AppKit)
>
> To find out which modules are exported, we filter imports according to
> restrictions:
>
> > exported(Foundation) = filterByModuleMapRestrictions(imports(Foundation))
>
> Because Foundation imports CoreFoundation (not CoreFoundation.CFArray), the
> CFArray submodule is considered not exported from Foundation, and is not
> visible from Cocoa (according to Module::isModuleVisible).
>
> Modified:
>     cfe/trunk/include/clang/Basic/Module.h
>     cfe/trunk/lib/Basic/Module.cpp
>
> Modified: cfe/trunk/include/clang/Basic/Module.h
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/Module.h?rev=193815&r1=193814&r2=193815&view=diff
>
> ==============================================================================
> --- cfe/trunk/include/clang/Basic/Module.h (original)
> +++ cfe/trunk/include/clang/Basic/Module.h Thu Oct 31 17:24:10 2013
> @@ -404,6 +404,9 @@ public:
>    submodule_const_iterator submodule_end() const { return
> SubModules.end(); }
>
>    /// \brief Returns the exported modules based on the wildcard
> restrictions.
> +  ///
> +  /// This returns a subset of immediately imported modules (the ones
> that are
> +  /// exported), not the complete set of exported modules.
>    void getExportedModules(SmallVectorImpl<Module *> &Exported) const;
>
>    static StringRef getModuleInputBufferName() {
>
> Modified: cfe/trunk/lib/Basic/Module.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Basic/Module.cpp?rev=193815&r1=193814&r2=193815&view=diff
>
> ==============================================================================
> --- cfe/trunk/lib/Basic/Module.cpp (original)
> +++ cfe/trunk/lib/Basic/Module.cpp Thu Oct 31 17:24:10 2013
> @@ -252,15 +252,23 @@ void Module::buildVisibleModulesCache()
>    // This module is visible to itself.
>    VisibleModulesCache.insert(this);
>
> -  llvm::SmallVector<Module*, 4> Exported;
> -  for (unsigned I = 0, N = Imports.size(); I != N; ++I) {
> -    // Every imported module is visible.
> -    VisibleModulesCache.insert(Imports[I]);
> +  // Every imported module is visible.
> +  // Every module exported by an imported module is visible.
> +  llvm::SmallPtrSet<Module *, 4> Visited;
> +  llvm::SmallVector<Module *, 4> Exports;
> +  SmallVector<Module *, 4> Stack(Imports.begin(), Imports.end());
> +  while (!Stack.empty()) {
> +    Module *CurrModule = Stack.pop_back_val();
> +    VisibleModulesCache.insert(CurrModule);
>
> -    // Every module exported by an imported module is visible.
> -    Imports[I]->getExportedModules(Exported);
> -    VisibleModulesCache.insert(Exported.begin(), Exported.end());
> -    Exported.clear();
> +    CurrModule->getExportedModules(Exports);
> +    for (SmallVectorImpl<Module *>::iterator I = Exports.begin(),
> +                                             E = Exports.end();
> +         I != E; ++I) {
> +      Module *Exported = *I;
> +      if (Visited.insert(Exported))
> +        Stack.push_back(Exported);
> +    }
>    }
>  }
>
>
>
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