Merge pull request #77039 from cachemeifyoucan/eng/PR-137610484

[ModuleCache] Prefer module cache passed on the command-line for checker

Author: cachemeifyoucan

lib/Frontend/Frontend.cpp

@@ -818,8 +818,11 @@ bool CompilerInstance::setUpModuleLoaders() {
   }
 
   // Configure ModuleInterfaceChecker for the ASTContext.
+  auto CacheFromInvocation = getInvocation().getClangModuleCachePath();
   auto const &Clang = clangImporter->getClangInstance();
-  std::string ModuleCachePath = getModuleCachePathFromClang(Clang);
+  std::string ModuleCachePath = CacheFromInvocation.empty()
+                                    ? getModuleCachePathFromClang(Clang)
+                                    : CacheFromInvocation.str();
   auto &FEOpts = Invocation.getFrontendOptions();
   ModuleInterfaceLoaderOptions LoaderOpts(FEOpts);
   Context->addModuleInterfaceChecker(

test/ModuleInterface/ModuleCache/module-cache-options.swift

@@ -0,0 +1,39 @@
+// UNSUPPORTED: OS=windows-msvc
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// RUN: %target-swift-frontend -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -parse-stdlib -I %t -emit-module-interface-path %t/LeafModule.swiftinterface -module-name LeafModule %t/leaf.swift -emit-module -o /dev/null
+// RUN: %target-swift-frontend -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -parse-stdlib -I %t -module-cache-path %t/swiftcache -emit-module-interface-path %t/OtherModule.swiftinterface -module-name OtherModule %t/other.swift -emit-module -o /dev/null
+// RUN: %target-swift-frontend -disable-implicit-concurrency-module-import -disable-implicit-string-processing-module-import -parse-stdlib -I %t -module-cache-path %t/swiftcache -Xcc -fmodules-cache-path=%t/clangcache -emit-module -o %t/TestModule.swiftmodule -module-name TestModule %t/main.swift
+
+// RUN: NUM_SWIFT_MODULES=$(find %t/swiftcache -type f -name '*.swiftmodule' | wc -l)
+// RUN: NUM_CLANG_MODULES=$(find %t/clangcache -type f -name '*.pcm' | wc -l)
+/// Two swift modules, Leaf and Other
+// RUN: if [ ! $NUM_SWIFT_MODULES -eq 2 ]; then echo "Should only be 2 Swift Modules, found $NUM_SWIFT_MODULES"; exit 1; fi
+/// Two clang modules, shim and A
+// RUN: if [ ! $NUM_CLANG_MODULES -eq 2 ]; then echo "Should only be 2 Clang Modules, found $NUM_CLANG_MODULES"; exit 1; fi
+
+//--- leaf.swift
+public func LeafFunc() {}
+
+//--- other.swift
+import LeafModule
+public func OtherFunc() {}
+
+//--- module.modulemap
+module A {
+  header "A.h"
+  export *
+}
+
+//--- A.h
+void a(void);
+
+//--- main.swift
+import OtherModule
+import A
+
+public func TestFunc() {
+    OtherFunc()
+    a()
+}