[IncludeTree] Support DepScan using IncludeTree and ModuleName

Teach IncludeTreeDepScanning to support ModuleName inputs.

(cherry picked from commit d1caf7e)

Author: cachemeifyoucan

clang/lib/Frontend/FrontendActions.cpp

@@ -1195,6 +1195,7 @@ void GetDependenciesByModuleNameAction::ExecuteAction() {
   Preprocessor &PP = CI.getPreprocessor();
   SourceManager &SM = PP.getSourceManager();
   FileID MainFileID = SM.getMainFileID();
+  PP.EnterSourceFile(MainFileID, nullptr, SourceLocation());
   SourceLocation FileStart = SM.getLocForStartOfFile(MainFileID);
   SmallVector<std::pair<IdentifierInfo *, SourceLocation>, 2> Path;
   IdentifierInfo *ModuleID = PP.getIdentifierInfo(ModuleName);

clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp

@@ -27,6 +27,7 @@
 #include "clang/Tooling/DependencyScanning/ModuleDepCollector.h"
 #include "clang/Tooling/DependencyScanning/ScanAndUpdateArgs.h"
 #include "clang/Tooling/Tooling.h"
+#include "llvm/CAS/CASProvidingFileSystem.h"
 #include "llvm/CAS/CachingOnDiskFileSystem.h"
 #include "llvm/CAS/ObjectStore.h"
 #include "llvm/Support/Allocator.h"
@@ -641,8 +642,6 @@ bool DependencyScanningWorker::computeDependencies(
     auto InMemoryFS =
         llvm::makeIntrusiveRefCnt<llvm::vfs::InMemoryFileSystem>();
     InMemoryFS->setCurrentWorkingDirectory(WorkingDirectory);
-    OverlayFS->pushOverlay(InMemoryFS);
-    ModifiedFS = OverlayFS;
 
     SmallString<128> FakeInputPath;
     // TODO: We should retry the creation if the path already exists.
@@ -651,6 +650,16 @@ bool DependencyScanningWorker::computeDependencies(
                                     /*MakeAbsolute=*/false);
     InMemoryFS->addFile(FakeInputPath, 0, llvm::MemoryBuffer::getMemBuffer(""));
 
+    llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> InMemoryOverlay =
+        InMemoryFS;
+    // If we are using a CAS but not dependency CASFS, we need to provide the
+    // fake input file in a CASProvidingFS for include-tree.
+    if (CAS && !DepCASFS)
+      InMemoryOverlay =
+          llvm::cas::createCASProvidingFileSystem(CAS, std::move(InMemoryFS));
+
+    OverlayFS->pushOverlay(InMemoryOverlay);
+    ModifiedFS = OverlayFS;
     ModifiedCommandLine = CommandLine;
     ModifiedCommandLine->emplace_back(FakeInputPath);
   }

clang/test/ClangScanDeps/modules-include-tree-by-mod-name.c

@@ -0,0 +1,98 @@
+// UNSUPPORTED: target=powerpc64-ibm-aix{{.*}}
+// REQUIRES: ondisk_cas
+
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+
+//--- module.modulemap
+module root { header "root.h" }
+module direct { header "direct.h" }
+module transitive { header "transitive.h" }
+//--- root.h
+#include "direct.h"
+#include "root/textual.h"
+//--- direct.h
+#include "transitive.h"
+//--- transitive.h
+// empty
+
+//--- root/textual.h
+// This is here to verify that the "root" directory doesn't clash with name of
+// the "root" module.
+
+//--- cdb.json.template
+[{
+  "file": "",
+  "directory": "DIR",
+  "command": "clang -fmodules -fmodules-cache-path=DIR/cache -I DIR -x c"
+}]
+
+// RUN: sed "s|DIR|%/t|g" %t/cdb.json.template > %t/cdb.json
+// RUN: clang-scan-deps -compilation-database %t/cdb.json \
+// RUN:   -cas-path %t/cas -format experimental-include-tree-full -module-name=root > %t/result.json
+// RUN: cat %t/result.json | sed 's:\\\\\?:/:g' | FileCheck -DPREFIX=%/t %s
+
+// CHECK:      {
+// CHECK-NEXT:   "modules": [
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "cache-key": "[[DIRECT_CACHE_KEY:llvmcas://[[:xdigit:]]+]]"
+// CHECK-NEXT:       "cas-include-tree-id": "[[LEFT_ROOT_ID:llvmcas://[[:xdigit:]]+]]"
+// CHECK-NEXT:       "clang-module-deps": [
+// CHECK-NEXT:         {
+// CHECK-NEXT:           "context-hash": "{{.*}}",
+// CHECK-NEXT:           "module-name": "transitive"
+// CHECK-NEXT:         }
+// CHECK-NEXT:       ],
+// CHECK-NEXT:       "clang-modulemap-file": "[[PREFIX]]/module.modulemap",
+// CHECK-NEXT:       "command-line": [
+// CHECK:              "-fmodule-file-cache-key"
+// CHECK-NEXT:         "{{.*transitive-.*\.pcm}}"
+// CHECK-NEXT:         "[[TRANSITIVE_CACHE_KEY:llvmcas://[[:xdigit:]]+]]"
+// CHECK:            ],
+// CHECK-NEXT:       "context-hash": "{{.*}}",
+// CHECK-NEXT:       "file-deps": [
+// CHECK-NEXT:         "[[PREFIX]]/direct.h"
+// CHECK-NEXT:         "[[PREFIX]]/module.modulemap"
+// CHECK-NEXT:       ],
+// CHECK-NEXT:       "name": "direct"
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "cache-key": "[[ROOT_CACHE_KEY:llvmcas://[[:xdigit:]]+]]"
+// CHECK-NEXT:       "cas-include-tree-id": "[[ROOT_ROOT_ID:llvmcas://[[:xdigit:]]+]]"
+// CHECK-NEXT:       "clang-module-deps": [
+// CHECK-NEXT:         {
+// CHECK-NEXT:           "context-hash": "{{.*}}",
+// CHECK-NEXT:           "module-name": "direct"
+// CHECK-NEXT:         }
+// CHECK-NEXT:       ],
+// CHECK-NEXT:       "clang-modulemap-file": "[[PREFIX]]/module.modulemap",
+// CHECK-NEXT:       "command-line": [
+// CHECK:              "-fmodule-file-cache-key"
+// CHECK-NEXT:         "{{.*direct-.*\.pcm}}"
+// CHECK-NEXT:         "[[DIRECT_CACHE_KEY]]"
+// CHECK:            ],
+// CHECK-NEXT:       "context-hash": "{{.*}}",
+// CHECK-NEXT:       "file-deps": [
+// CHECK-NEXT:         "[[PREFIX]]/module.modulemap"
+// CHECK-NEXT:         "[[PREFIX]]/root.h"
+// CHECK-NEXT:         "[[PREFIX]]/root/textual.h"
+// CHECK-NEXT:       ],
+// CHECK-NEXT:       "name": "root"
+// CHECK-NEXT:     },
+// CHECK-NEXT:     {
+// CHECK-NEXT:       "cache-key": "[[TRANSITIVE_CACHE_KEY]]"
+// CHECK-NEXT:       "cas-include-tree-id": "[[TRANSITIVE_ROOT_ID:llvmcas://[[:xdigit:]]+]]"
+// CHECK-NEXT:       "clang-module-deps": [],
+// CHECK-NEXT:       "clang-modulemap-file": "[[PREFIX]]/module.modulemap",
+// CHECK-NEXT:       "command-line": [
+// CHECK:            ],
+// CHECK-NEXT:       "context-hash": "{{.*}}",
+// CHECK-NEXT:       "file-deps": [
+// CHECK-NEXT:         "[[PREFIX]]/module.modulemap"
+// CHECK-NEXT:         "[[PREFIX]]/transitive.h"
+// CHECK-NEXT:       ],
+// CHECK-NEXT:       "name": "transitive"
+// CHECK-NEXT:     }
+// CHECK-NEXT:   ],
+// CHECK-NEXT:   "translation-units": []
+// CHECK-NEXT: }