[clang][module] Improve incomplete-umbrella warning

Change the warning message for -Wincomplete-umbrella to report the location of the umbrella header;

Differential Revision: https://reviews.llvm.org/D82118

Author: zixu-w

clang/lib/Lex/PPLexerChange.cpp

@@ -263,10 +263,12 @@ static void collectAllSubModulesWithUmbrellaHeader(
 }
 
 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))
+  const Module::Header &UmbrellaHeader = Mod.getUmbrellaHeader();
+  assert(UmbrellaHeader.Entry && "Module must use umbrella header");
+  const FileID &File = SourceMgr.translateFile(UmbrellaHeader.Entry);
+  SourceLocation ExpectedHeadersLoc = SourceMgr.getLocForEndOfFile(File);
+  if (getDiagnostics().isIgnored(diag::warn_uncovered_module_header,
+                                 ExpectedHeadersLoc))
     return;
 
   ModuleMap &ModMap = getHeaderSearchInfo().getModuleMap();
@@ -291,7 +293,7 @@ void Preprocessor::diagnoseMissingHeaderInUmbrellaDir(const Module &Mod) {
           // Find the relative path that would access this header.
           SmallString<128> RelativePath;
           computeRelativePath(FileMgr, Dir, *Header, RelativePath);
-          Diag(StartLoc, diag::warn_uncovered_module_header)
+          Diag(ExpectedHeadersLoc, diag::warn_uncovered_module_header)
               << Mod.getFullModuleName() << RelativePath;
         }
       }

clang/test/Modules/incomplete-umbrella.m

@@ -6,8 +6,12 @@
 #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'
+// CHECK: While building module 'Foo' imported from {{.*[/\]}}incomplete-umbrella.m:4:
+// CHECK-NEXT: In file included from <module-includes>:1:
+// CHECK-NEXT: {{.*Foo[.]framework[/\]Headers[/\]}}FooPublic.h:2:1: warning: umbrella header for module 'Foo' does not include header 'Bar.h'
+// CHECK: While building module 'Foo' imported from {{.*[/\]}}incomplete-umbrella.m:4:
+// CHECK-NEXT: In file included from <module-includes>:2:
+// CHECK-NEXT: {{.*Foo[.]framework[/\]PrivateHeaders[/\]}}Foo.h:2:1: warning: umbrella header for module 'Foo.Private' does not include header 'Baz.h'
 int foo() {
   int a = BAR_PUBLIC;
   int b = BAZ_PRIVATE;