[Caching] Avoid using clang CAS options in the command-line

Avoid constructing tasks with `-Xcc` options that references clang
CASOptions. This is going to make the cache hit/miss to be dependent on
CAS location/configuraitons.

Instead, only give swift CASOptions to constructed tasks and propagate
the configurations to underlying clang importer.

rdar://132255889

Author: cachemeifyoucan

lib/ClangImporter/ClangImporter.cpp

@@ -46,6 +46,7 @@
 #include "swift/Basic/Version.h"
 #include "swift/ClangImporter/ClangImporterRequests.h"
 #include "swift/ClangImporter/ClangModule.h"
+#include "swift/Option/Options.h"
 #include "swift/Parse/Lexer.h"
 #include "swift/Parse/ParseVersion.h"
 #include "swift/Parse/Parser.h"
@@ -65,6 +66,7 @@
 #include "clang/CodeGen/ObjectFilePCHContainerOperations.h"
 #include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Frontend/FrontendActions.h"
+#include "clang/Frontend/FrontendOptions.h"
 #include "clang/Frontend/IncludeTreePPActions.h"
 #include "clang/Frontend/TextDiagnosticPrinter.h"
 #include "clang/Frontend/Utils.h"
@@ -753,31 +755,6 @@ void importer::getNormalInvocationArguments(
   invocationArgStrs.push_back((llvm::Twine(searchPathOpts.RuntimeResourcePath) +
                                llvm::sys::path::get_separator() +
                                "apinotes").str());
-
-  auto CASOpts = ctx.CASOpts;
-  if (CASOpts.EnableCaching) {
-    invocationArgStrs.push_back("-Xclang");
-    invocationArgStrs.push_back("-fno-pch-timestamp");
-    if (!CASOpts.CASOpts.CASPath.empty()) {
-      invocationArgStrs.push_back("-Xclang");
-      invocationArgStrs.push_back("-fcas-path");
-      invocationArgStrs.push_back("-Xclang");
-      invocationArgStrs.push_back(CASOpts.CASOpts.CASPath);
-    }
-    if (!CASOpts.CASOpts.PluginPath.empty()) {
-      invocationArgStrs.push_back("-Xclang");
-      invocationArgStrs.push_back("-fcas-plugin-path");
-      invocationArgStrs.push_back("-Xclang");
-      invocationArgStrs.push_back(CASOpts.CASOpts.PluginPath);
-      for (auto Opt : CASOpts.CASOpts.PluginOptions) {
-        invocationArgStrs.push_back("-Xclang");
-        invocationArgStrs.push_back("-fcas-plugin-option");
-        invocationArgStrs.push_back("-Xclang");
-        invocationArgStrs.push_back(
-            (llvm::Twine(Opt.first) + "=" + Opt.second).str());
-      }
-    }
-  }
 }
 
 static void
@@ -1154,8 +1131,21 @@ std::optional<std::vector<std::string>> ClangImporter::getClangCC1Arguments(
     // to reduce the number of argument passing on the command-line and swift
     // compiler can be more efficient to compute swift cache key without having
     // the knowledge about clang command-line options.
-    if (ctx.CASOpts.EnableCaching)
+    if (ctx.CASOpts.EnableCaching) {
       CI->getCASOpts() = ctx.CASOpts.CASOpts;
+      // When clangImporter is used to compile (generate .pcm or .pch), need to
+      // inherit the include tree from swift args (last one wins) and clear the
+      // input file.
+      if ((CI->getFrontendOpts().ProgramAction ==
+               clang::frontend::ActionKind::GenerateModule ||
+           CI->getFrontendOpts().ProgramAction ==
+               clang::frontend::ActionKind::GeneratePCH) &&
+          ctx.ClangImporterOpts.HasClangIncludeTreeRoot) {
+        CI->getFrontendOpts().CASIncludeTreeID =
+            ctx.CASOpts.ClangIncludeTrees.back();
+        CI->getFrontendOpts().Inputs.clear();
+      }
+    }
 
     // If clang target is ignored, using swift target.
     if (ignoreClangTarget)

lib/ClangImporter/ClangModuleDependencyScanner.cpp

@@ -20,6 +20,7 @@
 #include "swift/ClangImporter/ClangImporter.h"
 #include "swift/Basic/Assertions.h"
 #include "clang/Basic/Diagnostic.h"
+#include "clang/CAS/CASOptions.h"
 #include "clang/Frontend/CompilerInvocation.h"
 #include "clang/Frontend/FrontendOptions.h"
 #include "clang/Tooling/DependencyScanning/DependencyScanningService.h"
@@ -242,6 +243,10 @@ ModuleDependencyVector ClangImporter::bridgeClangModuleDependencies(
     depsInvocation.getFrontendOpts().PathPrefixMappings.clear();
     depsInvocation.getFrontendOpts().OutputFile.clear();
 
+    // Reset CASOptions since that should be coming from swift.
+    depsInvocation.getCASOpts() = clang::CASOptions();
+    depsInvocation.getFrontendOpts().CASIncludeTreeID.clear();
+
     // FIXME: workaround for rdar://105684525: find the -ivfsoverlay option
     // from clang scanner and pass to swift.
     for (auto overlay : depsInvocation.getHeaderSearchOpts().VFSOverlayFiles) {

test/CAS/no-cas-path-dependency.swift

@@ -0,0 +1,66 @@
+// RUN: %empty-directory(%t)
+// RUN: split-file %s %t
+
+// 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 -parse-stdlib \
+// RUN:   %t/main.swift -o %t/deps.json -swift-version 5 -cache-compile-job -cas-path %t/cas -I %t/include
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json clang:A > %t/A.cmd
+// RUN: %swift_frontend_plain @%t/A.cmd -Rcache-compile-job 2>&1 | %FileCheck %s --check-prefix=CACHE-MISS
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps.json B > %t/B.cmd
+// RUN: %swift_frontend_plain @%t/B.cmd -Rcache-compile-job 2>&1 | %FileCheck %s --check-prefix=CACHE-MISS
+
+// 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 Test > %t/MyApp.cmd
+
+// RUN: %target-swift-frontend \
+// RUN:   -c -cache-compile-job -cas-path %t/cas \
+// RUN:   -swift-version 5 -disable-implicit-swift-modules \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
+// RUN:   -module-name Test -explicit-swift-module-map-file @%t/map.casid \
+// RUN:   %t/main.swift @%t/MyApp.cmd -Rcache-compile-job 2>&1 | %FileCheck %s --check-prefix=CACHE-MISS
+
+// CACHE-MISS: remark: cache miss for input
+// CACHE-HIT: remark: replay output file
+// CACHE-HIT-NOT: remark: cache miss for input
+
+// RUN: mv %t/cas %t/cas-2
+
+// 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 -parse-stdlib \
+// RUN:   %t/main.swift -o %t/deps-2.json -swift-version 5 -cache-compile-job -cas-path %t/cas-2 -I %t/include
+
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps-2.json clang:A > %t/A-2.cmd
+// RUN: %swift_frontend_plain @%t/A-2.cmd -Rcache-compile-job 2>&1 | %FileCheck %s --check-prefix=CACHE-HIT
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps-2.json B > %t/B-2.cmd
+// RUN: %swift_frontend_plain @%t/B-2.cmd -Rcache-compile-job 2>&1 | %FileCheck %s --check-prefix=CACHE-HIT
+
+// RUN: %{python} %S/Inputs/GenerateExplicitModuleMap.py %t/deps-2.json > %t/map-2.json
+// RUN: llvm-cas --cas %t/cas-2 --make-blob --data %t/map-2.json > %t/map-2.casid
+// RUN: %{python} %S/Inputs/BuildCommandExtractor.py %t/deps-2.json Test > %t/MyApp-2.cmd
+
+// RUN: %target-swift-frontend \
+// RUN:   -c -cache-compile-job -cas-path %t/cas-2 \
+// RUN:   -swift-version 5 -disable-implicit-swift-modules \
+// RUN:   -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib \
+// RUN:   -module-name Test -explicit-swift-module-map-file @%t/map-2.casid \
+// RUN:   %t/main.swift @%t/MyApp-2.cmd -Rcache-compile-job 2>&1 | %FileCheck %s --check-prefix=CACHE-HIT
+
+//--- main.swift
+import A
+import B
+
+//--- include/A.h
+void a(void);
+
+//--- include/module.modulemap
+module A {
+  header "A.h"
+  export *
+}
+
+//--- include/B.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name B -O -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib -user-module-version 1.0
+public func c() { }