Revert "Reapply "[clang][modules-driver] Add support for C++ named modules and import std" (#193857)

Reverts #193815 due to a test failure
(`clang/test/Driver/modules-driver-import-std.cpp`) on some systems.

Author: naveen-seth

clang/include/clang/Basic/DiagnosticDriverKinds.td

@@ -613,8 +613,6 @@ def err_drv_reduced_module_output_overrided : Warning<
   "please consider use '-fmodule-output=' to specify the output file for reduced BMI explicitly">,
   InGroup<DiagGroup<"reduced-bmi-output-overrided">>;
 
-def err_drv_modules_driver_requires_reduced_bmi : Error<
-  "'-fmodules-driver' is currently incompatible with '-fno-modules-reduced-bmi'">;
 def remark_performing_driver_managed_module_build : Remark<
   "performing driver managed module build">, InGroup<ModulesDriver>;
 def remark_modules_manifest_not_found : Remark<

clang/include/clang/Driver/ModulesDriver.h

@@ -32,10 +32,6 @@ class Compilation;
 
 namespace clang::driver::modules {
 
-/// Emits diagnostics for arguments incompatible with -fmodules-driver.
-void diagnoseModulesDriverArgs(llvm::opt::DerivedArgList &DAL,
-                               DiagnosticsEngine &Diags);
-
 /// The parsed Standard library module manifest.
 struct StdModuleManifest {
   struct Module {

clang/lib/Driver/Driver.cpp

@@ -1837,8 +1837,6 @@ Compilation *Driver::BuildCompilation(ArrayRef<const char *> ArgList) {
   if (UseModulesDriver) {
     Diags.Report(diag::remark_performing_driver_managed_module_build);
 
-    modules::diagnoseModulesDriverArgs(C->getArgs(), Diags);
-
     // Read the Standard library module manifest and, if available, add all
     // discovered modules to this Compilation. Jobs for modules specified in
     // the manifest that are not required by any command-line input are pruned

clang/lib/Driver/ModulesDriver.cpp

@@ -21,7 +21,6 @@
 #include "clang/Driver/Job.h"
 #include "clang/Driver/Tool.h"
 #include "clang/Driver/ToolChain.h"
-#include "clang/Driver/Types.h"
 #include "clang/Frontend/StandaloneDiagnostic.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/DepthFirstIterator.h"
@@ -48,14 +47,6 @@ using namespace clang;
 using namespace driver;
 using namespace modules;
 
-void driver::modules::diagnoseModulesDriverArgs(llvm::opt::DerivedArgList &DAL,
-                                                DiagnosticsEngine &Diags) {
-  if (!DAL.hasFlag(options::OPT_fmodules_reduced_bmi,
-                   options::OPT_fno_modules_reduced_bmi, true)) {
-    Diags.Report(diag::err_drv_modules_driver_requires_reduced_bmi);
-  }
-}
-
 namespace clang::driver::modules {
 static bool fromJSON(const llvm::json::Value &Params,
                      StdModuleManifest::Module::LocalArguments &LocalArgs,
@@ -1261,16 +1252,6 @@ static SmallVector<JobNode *> createNodesForUnusedStdlibModuleJobs(
   return StdlibModuleNodesToPrune;
 }
 
-// Returns the derived argument list for the tool chain responsible
-// for creating \p Job.
-static const DerivedArgList &getToolChainArgs(Compilation &C,
-                                              const Command &Job) {
-  const auto &TC = Job.getCreator().getToolChain();
-  const auto &SourceAction = Job.getSource();
-  return C.getArgsForToolChain(&TC, SourceAction.getOffloadingArch(),
-                               SourceAction.getOffloadingDeviceKind());
-}
-
 /// Creates a job for the Clang module described by \p MD.
 static std::unique_ptr<Command>
 createClangModulePrecompileJob(Compilation &C, const Command &ImportingJob,
@@ -1282,7 +1263,9 @@ createClangModulePrecompileJob(Compilation &C, const Command &ImportingJob,
   Action *PA = C.MakeAction<PrecompileJobAction>(IA, types::ID::TY_ModuleFile);
   PA->propagateOffloadInfo(&ImportingJob.getSource());
 
-  const auto &TCArgs = getToolChainArgs(C, ImportingJob);
+  const auto &TC = ImportingJob.getCreator().getToolChain();
+  const auto &TCArgs = C.getArgsForToolChain(&TC, PA->getOffloadingArch(),
+                                             PA->getOffloadingDeviceKind());
 
   const auto &BuildArgs = MD.getBuildArguments();
   ArgStringList JobArgs;
@@ -1336,7 +1319,12 @@ installScanCommandLines(Compilation &C,
     ArgStringList JobArgs;
     JobArgs.reserve(BuildArgs.size());
 
-    auto &TCArgs = getToolChainArgs(C, Job);
+    const auto &SourceAction = Job.getSource();
+    const auto &TC = Job.getCreator().getToolChain();
+    auto &TCArgs =
+        C.getArgsForToolChain(&TC, SourceAction.getOffloadingArch(),
+                              SourceAction.getOffloadingDeviceKind());
+
     for (const auto &Arg : BuildArgs)
       JobArgs.push_back(TCArgs.MakeArgString(Arg));
 
@@ -1539,73 +1527,6 @@ static void createAndConnectRoot(CompilationGraph &Graph) {
   }
 }
 
-/// Creates a temporary output path for \p ModuleName.
-static std::string createModuleOutputPath(const Compilation &C,
-                                          StringRef ModuleName) {
-  // Sanitize the ':' included in parition names. It is illegal for filenames on
-  // Windows.
-  SmallString<32> SanitizedModuleName(ModuleName);
-  llvm::replace(SanitizedModuleName, ':', '-');
-  auto ModuleOutputPath = C.getDriver().GetTemporaryPath(
-      SanitizedModuleName, types::getTypeTempSuffix(types::TY_ModuleFile));
-  return ModuleOutputPath;
-}
-
-/// Adds the '-fmodule-output=' argument for the module produced by \p Node.
-static void configureNamedModuleOutputArg(Compilation &C,
-                                          NamedModuleJobNode &Node,
-                                          StringRef ModuleOutputPath) {
-  auto &Job = *Node.Job;
-  const auto &TCArgs = getToolChainArgs(C, Job);
-  auto JobArgs = Job.getArguments();
-  JobArgs.push_back(
-      TCArgs.MakeArgString("-fmodule-output=" + ModuleOutputPath));
-  Job.replaceArguments(std::move(JobArgs));
-}
-
-/// Propagates the '-fmodule-file=' mapping for the named module described by
-/// \p Node to each dependent job.
-static void propagateModuleFileMappingArg(Compilation &C,
-                                          NamedModuleJobNode &Node,
-                                          StringRef ModuleOutputPath) {
-  const StringRef ModuleName = Node.InputDeps.ModuleName;
-
-  auto DependentNodes = llvm::drop_begin(llvm::depth_first<CGNode *>(&Node));
-  auto DependentScannedNodes = llvm::map_range(
-      llvm::make_filter_range(DependentNodes, llvm::IsaPred<ScannedJobNode>),
-      llvm::CastTo<ScannedJobNode>);
-
-  for (ScannedJobNode *DependentNode : DependentScannedNodes) {
-    auto &DependentJob = *DependentNode->Job;
-    const auto &TCArgs = getToolChainArgs(C, DependentJob);
-    auto JobArgs = DependentJob.getArguments();
-    JobArgs.push_back(TCArgs.MakeArgString("-fmodule-file=" + ModuleName + "=" +
-                                           ModuleOutputPath));
-    DependentJob.replaceArguments(std::move(JobArgs));
-  }
-}
-
-/// Finalizes command lines for C++20 named module dependencies.
-///
-/// The command lines produced by dependency scanning are only adjusted to
-/// handle discovered Clang modules. For C++20 named modules, we update the
-/// command-lines here.
-static void fixupNamedModuleCommandLines(Compilation &C,
-                                         CompilationGraph &Graph) {
-  const auto NamedModuleNodes = llvm::map_range(
-      llvm::make_filter_range(Graph, llvm::IsaPred<NamedModuleJobNode>),
-      llvm::CastTo<NamedModuleJobNode>);
-
-  for (NamedModuleJobNode *Node : NamedModuleNodes) {
-    const StringRef ModuleName = Node->InputDeps.ModuleName;
-    const auto ModuleOutputPath = createModuleOutputPath(C, ModuleName);
-    C.addTempFile(C.getArgs().MakeArgString(ModuleOutputPath));
-
-    configureNamedModuleOutputArg(C, *Node, ModuleOutputPath);
-    propagateModuleFileMappingArg(C, *Node, ModuleOutputPath);
-  }
-}
-
 /// Moves jobs from \p Graph into \p C in the graph's topological order.
 static void feedJobsBackIntoCompilation(Compilation &C,
                                         CompilationGraph &&Graph) {
@@ -1679,6 +1600,7 @@ void driver::modules::runModulesDriver(
   if (!Diags.isLastDiagnosticIgnored())
     llvm::WriteGraph<const CompilationGraph *>(llvm::errs(), &Graph);
 
-  fixupNamedModuleCommandLines(C, Graph);
+  // TODO: Fix-up command-lines for named module imports.
+
   feedJobsBackIntoCompilation(C, std::move(Graph));
 }