Modules: Make missing headers in a module.map a warning not an error.

Instead, mark the module as unavailable so that clang errors as soon as
someone tries to build this module.

A better long-term strategy might be to not stat the header files at all
while reading the module map and instead read them only when the module
is being built (there is a corresponding FIXME in parseHeaderDecl()).
However, it seems non-trivial to get there and this would be a temporary
solution to unblock us.

Also changed the implementation to reuse the same DiagnosticsEngine as
otherwise warnings can't be enabled or disabled with command-line flags.

llvm-svn: 197388

2 files changed, 11 insertions, 18 deletions

diff --git a/clang/lib/Lex/HeaderSearch.cpp b/clang/lib/Lex/HeaderSearch.cpp
index 5770aaadf40..254c0293df9 100644
--- a/clang/lib/Lex/HeaderSearch.cpp
+++ b/clang/lib/Lex/HeaderSearch.cpp
@@ -48,7 +48,7 @@ HeaderSearch::HeaderSearch(IntrusiveRefCntPtr<HeaderSearchOptions> HSOpts,
                            const LangOptions &LangOpts, 
                            const TargetInfo *Target)
   : HSOpts(HSOpts), FileMgr(SourceMgr.getFileManager()), FrameworkMap(64),
-    ModMap(SourceMgr, *Diags.getClient(), LangOpts, Target, *this)
+    ModMap(SourceMgr, Diags, LangOpts, Target, *this)
 {
   AngledDirIdx = 0;
   SystemDirIdx = 0;
diff --git a/clang/lib/Lex/ModuleMap.cpp b/clang/lib/Lex/ModuleMap.cpp
index 8a1fcaa69e7..59cb40151a3 100644
--- a/clang/lib/Lex/ModuleMap.cpp
+++ b/clang/lib/Lex/ModuleMap.cpp
@@ -59,7 +59,7 @@ Module *ModuleMap::resolveModuleId(const ModuleId &Id, Module *Mod,
   Module *Context = lookupModuleUnqualified(Id[0].first, Mod);
   if (!Context) {
     if (Complain)
-      Diags->Report(Id[0].second, diag::err_mmap_missing_module_unqualified)
+      Diags.Report(Id[0].second, diag::err_mmap_missing_module_unqualified)
       << Id[0].first << Mod->getFullModuleName();
 
     return 0;
@@ -70,7 +70,7 @@ Module *ModuleMap::resolveModuleId(const ModuleId &Id, Module *Mod,
     Module *Sub = lookupModuleQualified(Id[I].first, Context);
     if (!Sub) {
       if (Complain)
-        Diags->Report(Id[I].second, diag::err_mmap_missing_module_qualified)
+        Diags.Report(Id[I].second, diag::err_mmap_missing_module_qualified)
         << Id[I].first << Context->getFullModuleName()
         << SourceRange(Id[0].second, Id[I-1].second);
 
@@ -83,19 +83,12 @@ Module *ModuleMap::resolveModuleId(const ModuleId &Id, Module *Mod,
   return Context;
 }
 
-ModuleMap::ModuleMap(SourceManager &SourceMgr, DiagnosticConsumer &DC,
+ModuleMap::ModuleMap(SourceManager &SourceMgr, DiagnosticsEngine &Diags,
                      const LangOptions &LangOpts, const TargetInfo *Target,
                      HeaderSearch &HeaderInfo)
-    : SourceMgr(SourceMgr), LangOpts(LangOpts), Target(Target),
+    : SourceMgr(SourceMgr), Diags(Diags), LangOpts(LangOpts), Target(Target),
       HeaderInfo(HeaderInfo), BuiltinIncludeDir(0), CompilingModule(0),
-      SourceModule(0) {
-  IntrusiveRefCntPtr<DiagnosticIDs> DiagIDs(new DiagnosticIDs);
-  Diags = IntrusiveRefCntPtr<DiagnosticsEngine>(
-            new DiagnosticsEngine(DiagIDs, new DiagnosticOptions));
-  Diags->setClient(new ForwardingDiagnosticConsumer(DC),
-                   /*ShouldOwnClient=*/true);
-  Diags->setSourceManager(&SourceMgr);
-}
+      SourceModule(0) {}
 
 ModuleMap::~ModuleMap() {
   for (llvm::StringMap<Module *>::iterator I = Modules.begin(), 
@@ -1578,9 +1571,11 @@ void ModuleMapParser::parseHeaderDecl(MMToken::TokenKind LeadingToken,
   } else if (LeadingToken != MMToken::ExcludeKeyword) {
     // Ignore excluded header files. They're optional anyway.
     
-    Diags.Report(FileNameLoc, diag::err_mmap_header_not_found)
+    // If we find a module that has a missing header, we mark this module as
+    // unavailable. Layering warnings like -fmodules-decluse can still be used.
+    ActiveModule->IsAvailable = false;
+    Diags.Report(FileNameLoc, diag::warn_mmap_header_not_found)
       << (LeadingToken == MMToken::UmbrellaKeyword) << FileName;
-    HadError = true;
   }
 }
 
@@ -2119,11 +2114,9 @@ bool ModuleMap::parseModuleMapFile(const FileEntry *File, bool IsSystem) {
   
   // Parse this module map file.
   Lexer L(ID, SourceMgr.getBuffer(ID), SourceMgr, MMapLangOpts);
-  Diags->getClient()->BeginSourceFile(MMapLangOpts);
-  ModuleMapParser Parser(L, SourceMgr, Target, *Diags, *this, File->getDir(),
+  ModuleMapParser Parser(L, SourceMgr, Target, Diags, *this, File->getDir(),
                          BuiltinIncludeDir, IsSystem);
   bool Result = Parser.parseModuleMapFile();
-  Diags->getClient()->EndSourceFile();
   ParsedModuleMap[File] = Result;
   return Result;
 }