[Caching] Embed bridging header in binary module correctly when caching

include/swift/AST/DiagnosticsClangImporter.def

@@ -42,6 +42,8 @@ WARNING(could_not_rewrite_bridging_header,none,
 ERROR(bridging_header_pch_error,Fatal,
    "failed to emit precompiled header '%0' for bridging header '%1'",
    (StringRef, StringRef))
+ERROR(err_rewrite_bridging_header,none,
+  "failed to serialize bridging header: '%0'", (StringRef))
 
 ERROR(emit_pcm_error,Fatal,
    "failed to emit precompiled module '%0' for module map '%1'",

include/swift/ClangImporter/ClangImporter.h

@@ -402,8 +402,10 @@ class ClangImporter final : public ClangModuleLoader {
   getWrapperForModule(const clang::Module *mod,
                       bool returnOverlayIfPossible = false) const override;
 
-  std::string getBridgingHeaderContents(StringRef headerPath, off_t &fileSize,
-                                        time_t &fileModTime);
+  std::string
+  getBridgingHeaderContents(StringRef headerPath, off_t &fileSize,
+                            time_t &fileModTime,
+                            StringRef pchIncludeTree);
 
   /// Makes a temporary replica of the ClangImporter's CompilerInstance, reads
   /// an Objective-C header file into the replica and emits a PCH file of its

lib/ClangImporter/ClangImporter.cpp

@@ -55,13 +55,16 @@
 #include "clang/Basic/DiagnosticOptions.h"
 #include "clang/Basic/FileEntry.h"
 #include "clang/Basic/IdentifierTable.h"
+#include "clang/Basic/LangStandard.h"
 #include "clang/Basic/Module.h"
 #include "clang/Basic/TargetInfo.h"
 #include "clang/Basic/Version.h"
 #include "clang/CAS/CASOptions.h"
+#include "clang/CAS/IncludeTree.h"
 #include "clang/CodeGen/ObjectFilePCHContainerOperations.h"
 #include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Frontend/FrontendActions.h"
+#include "clang/Frontend/IncludeTreePPActions.h"
 #include "clang/Frontend/TextDiagnosticPrinter.h"
 #include "clang/Frontend/Utils.h"
 #include "clang/Index/IndexingAction.h"
@@ -80,7 +83,11 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/CAS/CASReference.h"
+#include "llvm/CAS/ObjectStore.h"
 #include "llvm/Support/CrashRecoveryContext.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FileCollector.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Memory.h"
@@ -1720,8 +1727,13 @@ bool ClangImporter::importHeader(StringRef header, ModuleDecl *adapter,
                                  StringRef cachedContents, SourceLoc diagLoc) {
   clang::FileManager &fileManager = Impl.Instance->getFileManager();
   auto headerFile = fileManager.getFile(header, /*OpenFile=*/true);
+  // Prefer importing the header directly if the header content matches by
+  // checking size and mod time. This allows correct import if some no-modular
+  // headers are already imported into clang importer. If mod time is zero, then
+  // the module should be built from CAS and there is no mod time to verify.
   if (headerFile && (*headerFile)->getSize() == expectedSize &&
-      (*headerFile)->getModificationTime() == expectedModTime) {
+      (expectedModTime == 0 ||
+       (*headerFile)->getModificationTime() == expectedModTime)) {
     return importBridgingHeader(header, adapter, diagLoc, false, true);
   }
 
@@ -1776,16 +1788,46 @@ bool ClangImporter::importBridgingHeader(StringRef header, ModuleDecl *adapter,
                            std::move(sourceBuffer), implicitImport);
 }
 
-std::string ClangImporter::getBridgingHeaderContents(StringRef headerPath,
-                                                     off_t &fileSize,
-                                                     time_t &fileModTime) {
+static llvm::Expected<llvm::cas::ObjectRef>
+setupIncludeTreeInput(clang::CompilerInvocation &invocation,
+                      StringRef headerPath, StringRef pchIncludeTree) {
+  auto DB = invocation.getCASOpts().getOrCreateDatabases();
+  if (!DB)
+    return DB.takeError();
+  auto CAS = DB->first;
+  auto ID = CAS->parseID(pchIncludeTree);
+  if (!ID)
+    return ID.takeError();
+  auto includeTreeRef = CAS->getReference(*ID);
+  if (!includeTreeRef)
+    return llvm::cas::ObjectStore::createUnknownObjectError(*ID);
+
+  invocation.getFrontendOpts().Inputs.push_back(clang::FrontendInputFile(
+      *includeTreeRef, headerPath, clang::Language::ObjC));
+
+  return *includeTreeRef;
+}
+
+std::string ClangImporter::getBridgingHeaderContents(
+    StringRef headerPath, off_t &fileSize, time_t &fileModTime,
+    StringRef pchIncludeTree) {
   auto invocation =
       std::make_shared<clang::CompilerInvocation>(*Impl.Invocation);
 
   invocation->getFrontendOpts().DisableFree = false;
   invocation->getFrontendOpts().Inputs.clear();
-  invocation->getFrontendOpts().Inputs.push_back(
-      clang::FrontendInputFile(headerPath, clang::Language::ObjC));
+
+  std::optional<llvm::cas::ObjectRef> includeTreeRef;
+  if (pchIncludeTree.empty())
+    invocation->getFrontendOpts().Inputs.push_back(
+        clang::FrontendInputFile(headerPath, clang::Language::ObjC));
+  else if (auto err =
+               setupIncludeTreeInput(*invocation, headerPath, pchIncludeTree)
+                   .moveInto(includeTreeRef)) {
+    Impl.diagnose({}, diag::err_rewrite_bridging_header,
+                  toString(std::move(err)));
+    return "";
+  }
 
   invocation->getPreprocessorOpts().resetNonModularOptions();
 
@@ -1806,18 +1848,36 @@ std::string ClangImporter::getBridgingHeaderContents(StringRef headerPath,
     // write to an in-memory buffer.
     class RewriteIncludesAction : public clang::PreprocessorFrontendAction {
       raw_ostream &OS;
+      std::optional<llvm::cas::ObjectRef> includeTreeRef;
 
       void ExecuteAction() override {
         clang::CompilerInstance &compiler = getCompilerInstance();
+        // If the input is include tree, setup the IncludeTreePPAction.
+        if (includeTreeRef) {
+          auto IncludeTreeRoot = clang::cas::IncludeTreeRoot::get(
+              compiler.getOrCreateObjectStore(), *includeTreeRef);
+          if (!IncludeTreeRoot)
+            llvm::report_fatal_error(IncludeTreeRoot.takeError());
+          auto PPCachedAct =
+              clang::createPPActionsFromIncludeTree(*IncludeTreeRoot);
+          if (!PPCachedAct)
+            llvm::report_fatal_error(PPCachedAct.takeError());
+          compiler.getPreprocessor().setPPCachedActions(
+              std::move(*PPCachedAct));
+        }
+
         clang::RewriteIncludesInInput(compiler.getPreprocessor(), &OS,
                                       compiler.getPreprocessorOutputOpts());
       }
+
     public:
-      explicit RewriteIncludesAction(raw_ostream &os) : OS(os) {}
+      explicit RewriteIncludesAction(
+          raw_ostream &os, std::optional<llvm::cas::ObjectRef> includeTree)
+          : OS(os), includeTreeRef(includeTree) {}
     };
 
     llvm::raw_string_ostream os(result);
-    RewriteIncludesAction action(os);
+    RewriteIncludesAction action(os, includeTreeRef);
     rewriteInstance.ExecuteAction(action);
   });
 
@@ -2553,6 +2613,7 @@ ClangImporter::Implementation::Implementation(
           !ctx.ClangImporterOpts.BridgingHeader.empty()),
       DisableOverlayModules(ctx.ClangImporterOpts.DisableOverlayModules),
       EnableClangSPI(ctx.ClangImporterOpts.EnableClangSPI),
+      UseClangIncludeTree(ctx.ClangImporterOpts.UseClangIncludeTree),
       importSymbolicCXXDecls(
           ctx.LangOpts.hasFeature(Feature::ImportSymbolicCXXDecls)),
       IsReadingBridgingPCH(false),

lib/ClangImporter/ImporterImpl.h

@@ -467,6 +467,7 @@ class LLVM_LIBRARY_VISIBILITY ClangImporter::Implementation
   const bool BridgingHeaderExplicitlyRequested;
   const bool DisableOverlayModules;
   const bool EnableClangSPI;
+  const bool UseClangIncludeTree;
   bool importSymbolicCXXDecls;
 
   bool IsReadingBridgingPCH;

lib/Serialization/Serialization.cpp

@@ -1321,21 +1321,25 @@ void Serializer::writeInputBlock() {
     time_t importedHeaderModTime = 0;
     std::string contents;
     auto importedHeaderPath = Options.ImportedHeader;
+    std::string pchIncludeTree;
     // We do not want to serialize the explicitly-specified .pch path if one was
     // provided. Instead we write out the path to the original header source so
     // that clients can consume it.
     if (Options.ExplicitModuleBuild &&
         llvm::sys::path::extension(importedHeaderPath)
-            .ends_with(file_types::getExtension(file_types::TY_PCH)))
-      importedHeaderPath = clangImporter->getClangInstance()
-                               .getASTReader()
-                               ->getModuleManager()
-                               .lookupByFileName(importedHeaderPath)
-                               ->OriginalSourceFileName;
+            .ends_with(file_types::getExtension(file_types::TY_PCH))) {
+      auto *pch = clangImporter->getClangInstance()
+                      .getASTReader()
+                      ->getModuleManager()
+                      .lookupByFileName(importedHeaderPath);
+      pchIncludeTree = pch->IncludeTreeID;
+      importedHeaderPath = pch->OriginalSourceFileName;
+    }
 
     if (!importedHeaderPath.empty()) {
       contents = clangImporter->getBridgingHeaderContents(
-          importedHeaderPath, importedHeaderSize, importedHeaderModTime);
+          importedHeaderPath, importedHeaderSize, importedHeaderModTime,
+          pchIncludeTree);
     }
     assert(publicImportSet.count(bridgingHeaderImport));
     ImportedHeader.emit(ScratchRecord,

test/CAS/bridging-header.swift

@@ -1,6 +1,12 @@
+// REQUIRES: objc_interop
 // RUN: %empty-directory(%t)
 // RUN: split-file %s %t
 
+// RUN: %target-swift-frontend -emit-module -o %t/temp.swiftmodule -module-name Test -swift-version 5 \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   -Xcc -fmodule-map-file=%t/a.modulemap -Xcc -fmodule-map-file=%t/b.modulemap -import-objc-header %t/Bridging.h \
+// RUN:   %t/test.swift
+
 // RUN: %target-swift-frontend -scan-dependencies -module-name Test -module-cache-path %t/clang-module-cache -O \
 // RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
 // RUN:   %t/test.swift -o %t/deps.json -swift-version 5 -cache-compile-job -cas-path %t/cas \
@@ -27,21 +33,103 @@
 // CHECK-NEXT:    "-Xcc",
 // CHECK-NEXT:    "llvmcas://{{.*}}"
 
+/// Try build then import from a non-caching compilation.
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json clang:SwiftShims > %t/shim.cmd
+// RUN: %swift_frontend_plain @%t/shim.cmd
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json clang:B > %t/B.cmd
+// RUN: %swift_frontend_plain @%t/B.cmd
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json clang:A > %t/A.cmd
+// RUN: %swift_frontend_plain @%t/A.cmd
+
+// RUN: %{python} %S/Inputs/GenerateExplicitModuleMap.py %t/deps.json > %t/map.json
+// RUN: llvm-cas --cas %t/cas --make-blob --data %t/map.json > %t/map.casid
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json bridgingHeader | tail -n +2  > %t/header.cmd
+// RUN: %target-swift-frontend @%t/header.cmd -disable-implicit-swift-modules %t/Bridging.h -O -o %t/bridging.pch
+// RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- \
+// RUN:   %target-swift-frontend @%t/header.cmd -disable-implicit-swift-modules %t/Bridging.h -O -o %t/bridging.pch > %t/keys.json
+// RUN: %{python} %S/Inputs/ExtractOutputKey.py %t/keys.json %t/Bridging.h > %t/key
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json Test > %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-string-processing-module-import\"" >> %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-concurrency-module-import\"" >> %t/MyApp.cmd
+// RUN: echo "\"-disable-implicit-swift-modules\"" >> %t/MyApp.cmd
+// RUN: echo "\"-import-objc-header\"" >> %t/MyApp.cmd
+// RUN: echo "\"%t/bridging.pch\"" >> %t/MyApp.cmd
+// RUN: echo "\"-bridging-header-pch-key\"" >> %t/MyApp.cmd
+// RUN: echo "\"@%t/key\"" >> %t/MyApp.cmd
+// RUN: echo "\"-explicit-swift-module-map-file\"" >> %t/MyApp.cmd
+// RUN: echo "\"@%t/map.casid\"" >> %t/MyApp.cmd
+
+// RUN: %target-swift-frontend  -cache-compile-job -module-name Test -O -cas-path %t/cas @%t/MyApp.cmd %t/test.swift \
+// RUN:   -emit-module -o %t/Test.swiftmodule
+
+/// Importing binary module with bridging header built from CAS from a regluar build.
+/// This should succeed even it is also importing a bridging header that shares same header dependencies (with proper header guard).
+// RUN: %target-swift-frontend -typecheck -module-name User -swift-version 5 \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   -Xcc -fmodule-map-file=%t/a.modulemap -Xcc -fmodule-map-file=%t/b.modulemap \
+// RUN:   -I %t %t/user.swift -import-objc-header %t/Bridging2.h
+
+/// Importing binary module with bridging header built from CAS from a cached build. This should work without additional bridging header deps.
+// RUN: %target-swift-frontend -scan-dependencies -module-name User -module-cache-path %t/clang-module-cache -O \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import \
+// RUN:   %t/user.swift -o %t/deps2.json -swift-version 5 -cache-compile-job -cas-path %t/cas \
+// RUN:   -Xcc -fmodule-map-file=%t/a.modulemap -Xcc -fmodule-map-file=%t/b.modulemap -I %t
+
+// RUN: %{python} %S/Inputs/GenerateExplicitModuleMap.py %t/deps2.json > %t/map2.json
+// RUN: llvm-cas --cas %t/cas --make-blob --data %t/map2.json > %t/map2.casid
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps2.json User > %t/User.cmd
+// RUN: %target-swift-frontend  -cache-compile-job -module-name User -O -cas-path %t/cas \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -disable-implicit-swift-modules \
+// RUN:   -explicit-swift-module-map-file @%t/map2.casid @%t/User.cmd %t/user.swift \
+// RUN:   -emit-module -o %t/User.swiftmodule
+
 //--- test.swift
-import B
-public func test() {}
+public func test() {
+    b()
+}
+public class TestB: B {}
+
+//--- user.swift
+import Test
+
+func user() {
+  var b: TestB
+  test()
+}
+
+extension A {
+    public func testA() {}
+}
+
 
 //--- Bridging.h
 #include "Foo.h"
+#include "Foo2.h"
+
+//--- Bridging2.h
+#include "Foo.h"
+#include "Foo2.h"
 
 //--- Foo.h
 #import "a.h"
 
+//--- Foo2.h
+#pragma once
+int Foo = 0;
+
 //--- a.h
 #include "b.h"
+struct A {
+  int a;
+};
 
 //--- b.h
 void b(void);
+@interface B
+@end
 
 //--- a.modulemap
 module A {