[Modules] Improve diagnostics for incomplete umbrella

[bruno]

Summary

One of the -Wincomplete-umbrella warnings diagnoses when a header is present in the directory but it's not present in the umbrella header. Currently, this warning only happens on top level modules; any submodule using an umbrella header does not get this warning. Fix that by also considering the submodules.

[dexonsmith]

LGTM after a couple of changes inline.

lib/Lex/PPLexerChange.cpp

290–292 ↗

(On Diff #96857)

I think you can take Mod by reference.

Also: I'm not sure if it can be const, but please check (also, SmallVectorImpl<const Module*>) and use const if possible.

299 ↗

(On Diff #96857)

Seems better to take Mod by reference here. Also, const if possible.

[dexonsmith]

Oh, and it would be nice to split out Preprocessor::diagnoseMissingHeaderInUmbrellaDir in a separate NFC commit ahead of time.

cfe/trunk/lib/Lex/PPLexerChange.cpp

if (EndPos != CurLexer->BufferStart &&
         (EndPos[-1] == '\n' || EndPos[-1] == '\r') &&
         EndPos[-1] != EndPos[0])
       --EndPos;
   }
 
   return EndPos;
 }
 
+static void collectAllSubModulesWithUmbrellaHeader(
+    const Module &Mod, SmallVectorImpl<const Module *> &SubMods) {
+  if (Mod.getUmbrellaHeader())
+    SubMods.push_back(&Mod);
+  for (auto *M : Mod.submodules())
+    collectAllSubModulesWithUmbrellaHeader(*M, SubMods);
+}
+
 void Preprocessor::diagnoseMissingHeaderInUmbrellaDir(const Module &Mod) {
   assert(Mod.getUmbrellaHeader() && "Module must use umbrella header");
   SourceLocation StartLoc =
       SourceMgr.getLocForStartOfFile(SourceMgr.getMainFileID());
   if (getDiagnostics().isIgnored(diag::warn_uncovered_module_header, StartLoc))
     return;
 
   ModuleMap &ModMap = getHeaderSearchInfo().getModuleMap();
if (TUKind == TU_Complete) {
     // used.
     for (WarnUnusedMacroLocsTy::iterator
            I=WarnUnusedMacroLocs.begin(), E=WarnUnusedMacroLocs.end();
            I!=E; ++I)
       Diag(*I, diag::pp_macro_not_used);
   }
 
   // If we are building a module that has an umbrella header, make sure that
-  // each of the headers within the directory covered by the umbrella header
-  // was actually included by the umbrella header.
-  if (Module *Mod = getCurrentModule())
-    diagnoseMissingHeaderInUmbrellaDir(*Mod);
+  // each of the headers within the directory, including all submodules, is
+  // covered by the umbrella header was actually included by the umbrella
+  // header.
+  if (Module *Mod = getCurrentModule()) {
+    llvm::SmallVector<const Module *, 4> AllMods;
+    collectAllSubModulesWithUmbrellaHeader(*Mod, AllMods);
+    for (auto *M : AllMods)
+      diagnoseMissingHeaderInUmbrellaDir(*M);
+  }
 
   return true;
 }
 
 /// HandleEndOfTokenLexer - This callback is invoked when the current TokenLexer
 /// hits the end of its token stream.
 bool Preprocessor::HandleEndOfTokenLexer(Token &Result) {
   assert(CurTokenLexer && !CurPPLexer &&

cfe/trunk/test/Modules/Inputs/incomplete-umbrella/Foo.framework/Headers/Bar.h

+#define BAR_PUBLIC 1

cfe/trunk/test/Modules/Inputs/incomplete-umbrella/Foo.framework/Headers/FooPublic.h

+// FooPublic.h

cfe/trunk/test/Modules/Inputs/incomplete-umbrella/Foo.framework/Modules/module.modulemap

+framework module Foo {
+    umbrella header "FooPublic.h"
+    requires objc
+    export *
+}

cfe/trunk/test/Modules/Inputs/incomplete-umbrella/Foo.framework/Modules/module.private.modulemap

+explicit module Foo.Private {
+    umbrella header "Foo.h"
+    requires objc
+    export *
+}

cfe/trunk/test/Modules/Inputs/incomplete-umbrella/Foo.framework/PrivateHeaders/Baz.h

+#define BAZ_PRIVATE 1

cfe/trunk/test/Modules/Inputs/incomplete-umbrella/Foo.framework/PrivateHeaders/Foo.h

+// Foo.h

cfe/trunk/test/Modules/incomplete-umbrella.m

+// RUN: rm -rf %t
+// RUN: not %clang_cc1 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -F%S/Inputs/incomplete-umbrella -fsyntax-only %s 2>&1 | FileCheck %s
+
+#import <Foo/Foo.h>
+#import <Foo/Bar.h>
+#import <Foo/Baz.h>
+@import Foo.Private;
+
+// CHECK: warning: umbrella header for module 'Foo' does not include header 'Bar.h'
+// CHECK: warning: umbrella header for module 'Foo.Private' does not include header 'Baz.h'
+int foo() {
+  int a = BAR_PUBLIC;
+  int b = BAZ_PRIVATE;
+  return 0;
+}