Stopgap fix for finding module for a file mapped in the VFS

If we lookup a path using its 'real' path first, we need to ensure that
when we run header search we still use the VFS-mapped path or we will
not be able to find the corresponding module for the header.

The real problem is that we tie the name of a file to its underlying
FileEntry, which is uniqued by inode, so we only ever get the first name
it is looked up by. This doesn't work with modules, which rely on a
specific file system structure.  I'm hoping to have time to write up a
proposal for fixing this more permanently soon, but as a stopgap this
patch updates the name of the file's directory if it comes from a VFS
mapping.

llvm-svn: 209534

clang/include/clang/Basic/FileSystemStatCache.h

@@ -38,6 +38,10 @@ struct FileData {
   bool IsDirectory;
   bool IsNamedPipe;
   bool InPCH;
+  bool IsVFSMapped; // FIXME: remove this when files support multiple names
+  FileData()
+      : Size(0), ModTime(0), IsDirectory(false), IsNamedPipe(false),
+        InPCH(false), IsVFSMapped(false) {}
 };
 
 /// \brief Abstract interface for introducing a FileManager cache for 'stat'

clang/include/clang/Basic/VirtualFileSystem.h

@@ -39,6 +39,9 @@ class Status {
   llvm::sys::fs::file_type Type;
   llvm::sys::fs::perms Perms;
 
+public:
+  bool IsVFSMapped; // FIXME: remove when files support multiple names
+
 public:
   Status() : Type(llvm::sys::fs::file_type::status_error) {}
   Status(const llvm::sys::fs::file_status &Status);

clang/lib/Basic/FileManager.cpp

@@ -274,6 +274,16 @@ const FileEntry *FileManager::getFile(StringRef Filename, bool openFile,
 
   NamedFileEnt.setValue(&UFE);
   if (UFE.isValid()) { // Already have an entry with this inode, return it.
+
+    // FIXME: this hack ensures that if we look up a file by a virtual path in
+    // the VFS that the getDir() will have the virtual path, even if we found
+    // the file by a 'real' path first. This is required in order to find a
+    // module's structure when its headers/module map are mapped in the VFS.
+    // We should remove this as soon as we can properly support a file having
+    // multiple names.
+    if (DirInfo != UFE.Dir && Data.IsVFSMapped)
+      UFE.Dir = DirInfo;
+
     // If the stat process opened the file, close it to avoid a FD leak.
     if (F)
       delete F;

clang/lib/Basic/FileSystemStatCache.cpp

@@ -39,6 +39,7 @@ static void copyStatusToFileData(const vfs::Status &Status,
   Data.IsDirectory = Status.isDirectory();
   Data.IsNamedPipe = Status.getType() == llvm::sys::fs::file_type::fifo_file;
   Data.InPCH = false;
+  Data.IsVFSMapped = Status.IsVFSMapped;
 }
 
 /// FileSystemStatCache::get - Get the 'stat' information for the specified

clang/lib/Basic/VirtualFileSystem.cpp

@@ -31,13 +31,13 @@ using llvm::sys::fs::UniqueID;
 Status::Status(const file_status &Status)
     : UID(Status.getUniqueID()), MTime(Status.getLastModificationTime()),
       User(Status.getUser()), Group(Status.getGroup()), Size(Status.getSize()),
-      Type(Status.type()), Perms(Status.permissions()) {}
+      Type(Status.type()), Perms(Status.permissions()), IsVFSMapped(false)  {}
 
 Status::Status(StringRef Name, StringRef ExternalName, UniqueID UID,
                sys::TimeValue MTime, uint32_t User, uint32_t Group,
                uint64_t Size, file_type Type, perms Perms)
     : Name(Name), UID(UID), MTime(MTime), User(User), Group(Group), Size(Size),
-      Type(Type), Perms(Perms) {}
+      Type(Type), Perms(Perms), IsVFSMapped(false) {}
 
 bool Status::equivalent(const Status &Other) const {
   return getUniqueID() == Other.getUniqueID();
@@ -801,6 +801,8 @@ ErrorOr<Status> VFSFromYAML::status(const Twine &Path) {
     assert(!S || S->getName() == F->getExternalContentsPath());
     if (S && !F->useExternalName(UseExternalNames))
       S->setName(PathStr);
+    if (S)
+      S->IsVFSMapped = true;
     return S;
   } else { // directory
     DirectoryEntry *DE = cast<DirectoryEntry>(*Result);

clang/test/VFS/Inputs/actual_module.map

@@ -2,3 +2,7 @@ module not_real {
   header "not_real.h"
   export *
 }
+module import_some_frame {
+  header "import_some_frame.h"
+  export *
+}

clang/test/VFS/Inputs/import_some_frame.h

@@ -0,0 +1,2 @@
+#import <SomeFramework/public_header.h>
+#import <SomeFramework/public_header2.h>

clang/test/VFS/Inputs/public_header.h

@@ -1 +1,2 @@
+#import <SomeFramework/public_header2.h>
 void from_framework(void);

clang/test/VFS/Inputs/public_header2.h

@@ -0,0 +1 @@
+// public_header2.h

clang/test/VFS/Inputs/some_frame_module.map

@@ -0,0 +1,5 @@
+framework module SomeFramework {
+  umbrella header "public_header.h"
+  export *
+  module * { export * }
+}

clang/test/VFS/Inputs/vfsoverlay.yaml

@@ -6,14 +6,26 @@
         { 'name': 'not_real.h', 'type': 'file',
           'external-contents': 'INPUT_DIR/actual_header.h'
         },
+        { 'name': 'import_some_frame.h', 'type': 'file',
+          'external-contents': 'INPUT_DIR/import_some_frame.h'
+        },
         { 'name': 'module.map', 'type': 'file',
           'external-contents': 'INPUT_DIR/actual_module.map'
         },
         { 'name': 'include_real.h', 'type': 'file',
           'external-contents': 'INPUT_DIR/include_real.h'
         },
-        { 'name': 'SomeFramework.framework/Headers/public_header.h', 'type': 'file',
-          'external-contents': 'INPUT_DIR/public_header.h'
+        { 'name': 'SomeFramework.framework', 'type': 'directory',
+          'contents': [
+            { 'name': 'Headers', 'type': 'directory',
+              'contents': [
+                { 'name': 'public_header.h', 'type': 'file',
+                  'external-contents': 'INPUT_DIR/public_header.h' },
+                { 'name': 'public_header2.h', 'type': 'file',
+                  'external-contents': 'INPUT_DIR/public_header2.h' }
+              ]
+            }
+          ]
         },
         { 'name': 'Foo.framework/Headers/Foo.h', 'type': 'file',
           'external-contents': 'INPUT_DIR/Foo.h'

clang/test/VFS/real-path-found-first.m

@@ -0,0 +1,74 @@
+// This test is for cases where we lookup a file by its 'real' path before we
+// use its VFS-mapped path. If we accidentally use the real path in header
+// search, we will not find a module for the headers.  To test that we
+// intentionally rebuild modules, since the precompiled module file refers to
+// the dependency files by real path.
+
+// REQUIRES: shell
+// RUN: rm -rf %t %t-cache %t.pch
+// RUN: mkdir -p %t/SomeFramework.framework/Modules
+// RUN: cp %S/Inputs/some_frame_module.map %t/SomeFramework.framework/Modules/module.modulemap
+// RUN: sed -e "s:INPUT_DIR:%S/Inputs:g" -e "s:OUT_DIR:%t:g" %S/Inputs/vfsoverlay.yaml > %t.yaml
+
+// Build
+// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t-cache -F %t \
+// RUN:     -ivfsoverlay %t.yaml -fsyntax-only %s -verify -Wauto-import \
+// RUN:     -Werror=non-modular-include-in-framework-module
+
+// Rebuild
+// RUN: echo ' ' >> %t/SomeFramework.framework/Modules/module.modulemap
+// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t-cache -F %t \
+// RUN:     -ivfsoverlay %t.yaml -fsyntax-only %s -verify -Wauto-import \
+// RUN:     -Werror=non-modular-include-in-framework-module
+
+// Load from PCH
+// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t-cache -F %t \
+// RUN:     -ivfsoverlay %t.yaml -emit-pch  %s -o %t.pch \
+// RUN:     -Werror=non-modular-include-in-framework-module \
+// RUN:     -fmodules-ignore-macro=WITH_PREFIX
+// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t-cache -F %t \
+// RUN:     -ivfsoverlay %t.yaml -include-pch %t.pch -fsyntax-only  %s \
+// RUN:     -Werror=non-modular-include-in-framework-module -DWITH_PREFIX \
+// RUN:     -fmodules-ignore-macro=WITH_PREFIX
+
+// While indexing
+// RUN: c-index-test -index-file %s -fmodules -fmodules-cache-path=%t-cache -F %t \
+// RUN:     -ivfsoverlay %t.yaml -fsyntax-only -Wauto-import \
+// RUN:     -Werror=non-modular-include-in-framework-module | FileCheck %s
+// RUN: echo ' ' >> %t/SomeFramework.framework/Modules/module.modulemap
+// RUN: c-index-test -index-file %s -fmodules -fmodules-cache-path=%t-cache -F %t \
+// RUN:     -ivfsoverlay %t.yaml -fsyntax-only -Wauto-import \
+// RUN:     -Werror=non-modular-include-in-framework-module | FileCheck %s
+// CHECK: warning: treating
+// CHECK-NOT: error
+
+// With a VFS-mapped module map file
+// RUN: mv %t/SomeFramework.framework/Modules/module.modulemap %t/hide_module.map
+// RUN: echo "{ 'version': 0, 'roots': [ { " > %t2.yaml
+// RUN: echo "'name': '%t/SomeFramework.framework/Modules/module.modulemap'," >> %t2.yaml
+// RUN: echo "'type': 'file', 'external-contents': '%t/hide_module.map' } ] }" >> %t2.yaml
+
+// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t-cache -F %t \
+// RUN:     -ivfsoverlay %t.yaml -ivfsoverlay %t2.yaml -fsyntax-only %s -verify \
+// RUN:     -Wauto-import -Werror=non-modular-include-in-framework-module
+// RUN: echo ' ' >> %t/hide_module.map
+// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t-cache -F %t \
+// RUN:     -ivfsoverlay %t.yaml -ivfsoverlay %t2.yaml -fsyntax-only %s -verify \
+// RUN:     -Wauto-import -Werror=non-modular-include-in-framework-module
+
+// Within a module build
+// RUN: echo '@import import_some_frame;' | \
+// RUN:   %clang_cc1 -fmodules -fmodules-cache-path=%t-cache -F %t \
+// RUN:      -ivfsoverlay %t.yaml -ivfsoverlay %t2.yaml -fsyntax-only - \
+// RUN:      -Werror=non-modular-include-in-framework-module -x objective-c -I %t
+// RUN: echo ' ' >> %t/hide_module.map
+// RUN: echo '@import import_some_frame;' | \
+// RUN:   %clang_cc1 -fmodules -fmodules-cache-path=%t-cache -F %t \
+// RUN:      -ivfsoverlay %t.yaml -ivfsoverlay %t2.yaml -fsyntax-only - \
+// RUN:      -Werror=non-modular-include-in-framework-module -x objective-c -I %t
+
+#ifndef WITH_PREFIX
+#import <SomeFramework/public_header.h> // expected-warning{{treating}}
+#import <SomeFramework/public_header2.h> // expected-warning{{treating}}
+@import SomeFramework.public_header2;
+#endif