Include system-ness of framework and import search paths in the PCH hash

This hash is also used for the dependency scanning hash. In both cases, PCH contents may differ based on whether a certain module they depend on is found in a system or non-system search path. In dependency scanning, systemness should cause a full change of scanning context requiring a from-scratch scan.

Resolves rdar://150334077

include/swift/AST/ASTContext.h

@@ -1094,9 +1094,6 @@ public:
   /// $SDKROOT/System/Library/Frameworks/ and $SDKROOT/Library/Frameworks/.
   std::vector<std::string> getDarwinImplicitFrameworkSearchPaths() const;
 
-  /// Return a set of all possible filesystem locations where modules can be found.
-  llvm::StringSet<> getAllModuleSearchPathsSet() const;
-
   /// Load extensions to the given nominal type from the external
   /// module loaders.
   ///

include/swift/AST/SearchPathOptions.h

@@ -323,6 +323,10 @@ public:
     friend bool operator!=(const SearchPath &LHS, const SearchPath &RHS) {
       return !(LHS == RHS);
     }
+    friend llvm::hash_code
+    hash_value(const SearchPath &searchPath) {
+      return llvm::hash_combine(searchPath.Path, searchPath.IsSystem);
+    }
   };
 
 private:
@@ -599,30 +603,17 @@ public:
   makeOverlayFileSystem(
       llvm::IntrusiveRefCntPtr<llvm::vfs::FileSystem> BaseFS) const;
 
-private:
-  static StringRef pathStringFromSearchPath(const SearchPath &next) {
-    return next.Path;
-  };
-
 public:
   /// Return a hash code of any components from these options that should
   /// contribute to a Swift Bridging PCH hash.
   llvm::hash_code getPCHHashComponents() const {
     using llvm::hash_combine;
     using llvm::hash_combine_range;
-
-    using SearchPathView =
-        ArrayRefView<SearchPath, StringRef, pathStringFromSearchPath>;
-    SearchPathView importPathsOnly{ImportSearchPaths};
-    SearchPathView frameworkPathsOnly{FrameworkSearchPaths};
-
     return hash_combine(SDKPath,
-                        // FIXME: Should we include the system-ness of
+                        hash_combine_range(ImportSearchPaths.begin(), ImportSearchPaths.end()),
-                        // search paths too?
-                        hash_combine_range(importPathsOnly.begin(), importPathsOnly.end()),
                         hash_combine_range(VFSOverlayFiles.begin(), VFSOverlayFiles.end()),
-                        hash_combine_range(frameworkPathsOnly.begin(),
+                        hash_combine_range(FrameworkSearchPaths.begin(),
-                                           frameworkPathsOnly.end()),
+                                           FrameworkSearchPaths.end()),
                         hash_combine_range(LibrarySearchPaths.begin(),
                                            LibrarySearchPaths.end()),
                         RuntimeResourcePath,

include/swift/DependencyScan/SerializedModuleDependencyCacheFormat.h

@@ -41,7 +41,7 @@ using llvm::BCVBR;
 const unsigned char MODULE_DEPENDENCY_CACHE_FORMAT_SIGNATURE[] = {'I', 'M', 'D','C'};
 const unsigned MODULE_DEPENDENCY_CACHE_FORMAT_VERSION_MAJOR = 9;
 /// Increment this on every change.
-const unsigned MODULE_DEPENDENCY_CACHE_FORMAT_VERSION_MINOR = 1;
+const unsigned MODULE_DEPENDENCY_CACHE_FORMAT_VERSION_MINOR = 2;
 
 /// Various identifiers in this format will rely on having their strings mapped
 /// using this ID.

lib/AST/ASTContext.cpp

@@ -2212,46 +2212,6 @@ const {
   return SearchPathOpts.getDarwinImplicitFrameworkSearchPaths();
 }
 
-llvm::StringSet<> ASTContext::getAllModuleSearchPathsSet()
-const {
-  llvm::StringSet<> result;
-
-  // Import and framework paths are "special", they contain more than path
-  // strings, but path strings are all we care about here.
-  using SearchPathView = ArrayRefView<SearchPathOptions::SearchPath, StringRef,
-                                      pathStringFromSearchPath>;
-
-  SearchPathView importPathsOnly{SearchPathOpts.getImportSearchPaths()};
-  result.insert(importPathsOnly.begin(), importPathsOnly.end());
-
-  SearchPathView frameworkPathsOnly{SearchPathOpts.getFrameworkSearchPaths()};
-  result.insert(frameworkPathsOnly.begin(), frameworkPathsOnly.end());
-
-  if (LangOpts.Target.isOSDarwin()) {
-    auto implicitFrameworkSearchPaths = getDarwinImplicitFrameworkSearchPaths();
-    result.insert(implicitFrameworkSearchPaths.begin(),
-                  implicitFrameworkSearchPaths.end());
-  }
-  result.insert(SearchPathOpts.RuntimeLibraryImportPaths.begin(),
-                SearchPathOpts.RuntimeLibraryImportPaths.end());
-
-  // ClangImporter special-cases the path for SwiftShims, so do the same here
-  // If there are no shims in the resource dir, add a search path in the SDK.
-  SmallString<128> shimsPath(SearchPathOpts.RuntimeResourcePath);
-  llvm::sys::path::append(shimsPath, "shims");
-  if (!llvm::sys::fs::exists(shimsPath)) {
-    shimsPath = SearchPathOpts.getSDKPath();
-    llvm::sys::path::append(shimsPath, "usr", "lib", "swift", "shims");
-  }
-  result.insert(shimsPath.str());
-
-  // Clang system modules are found in the SDK root
-  SmallString<128> clangSysRootPath(SearchPathOpts.getSDKPath());
-  llvm::sys::path::append(clangSysRootPath, "usr", "include");
-  result.insert(clangSysRootPath.str());
-  return result;
-}
-
 void ASTContext::loadExtensions(NominalTypeDecl *nominal,
                                 unsigned previousGeneration) {
   PrettyStackTraceDecl stackTrace("loading extensions for", nominal);

test/ScanDependencies/Incremental/system_search_path_invalidate.swift

@@ -0,0 +1,17 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/Frameworks)
+
+// RUN: %target-swift-frontend -scan-dependencies -scanner-module-validation -module-load-mode prefer-interface -Rdependency-scan-cache -load-dependency-scan-cache -serialize-dependency-scan-cache -dependency-scan-cache-path %t/cache.moddepcache -module-cache-path %t/module-cache %s -o %t/deps.json -I %t/ExtraCModules -I %S/../Inputs/CHeaders -F %t/Frameworks &> %t/first_scan_output.txt
+// RUN: cat %t/first_scan_output.txt | %FileCheck %s
+
+// RUN: %target-swift-frontend -scan-dependencies -scanner-module-validation -module-load-mode prefer-interface -Rdependency-scan-cache -load-dependency-scan-cache -serialize-dependency-scan-cache -dependency-scan-cache-path %t/cache.moddepcache -module-cache-path %t/module-cache %s -o %t/deps.json -I %t/ExtraCModules -I %S/../Inputs/CHeaders -F %t/Frameworks &> %t/second_scan_output.txt
+// RUN: cat %t/second_scan_output.txt | %FileCheck %s -check-prefix=INCREMENTAL-CHECK
+
+// Change an '-F' to a '-Fsystem' and ensure that the serialized cache does not get reused
+// RUN: %target-swift-frontend -scan-dependencies -scanner-module-validation -module-load-mode prefer-interface -Rdependency-scan-cache -load-dependency-scan-cache -serialize-dependency-scan-cache -dependency-scan-cache-path %t/cache.moddepcache -module-cache-path %t/module-cache %s -o %t/deps.json -I %t/ExtraCModules -I %S/../Inputs/CHeaders -Fsystem %t/Frameworks &> %t/second_system_scan_output.txt
+// RUN: cat %t/second_system_scan_output.txt | %FileCheck %s
+
+// CHECK: remark: Incremental module scan: Failed to load module scanning dependency cache from:
+// INCREMENTAL-CHECK-NOT: remark: Incremental module scan: Failed to load module scanning dependency cache from:
+