[Driver] Ignore the clang modules validation-related flags if clang modules are not enabled

[akyrtzi]

Summary

If clang modules are not enabled it becomes unnecessary to read the session timestamp file in order
to pass -fbuild-session-timestamp to the cc1 invocation.

[jansvoboda11]

LGTM!

clang/lib/Driver/ToolChains/Clang.cpp

static void RenderModulesOptions(Compilation &C, const Driver &D,
   if (HaveClangModules)
     Args.AddLastArg(CmdArgs, options::OPT_fmodules_user_build_path);
 
   // Pass through all -fmodules-ignore-macro arguments.
   Args.AddAllArgs(CmdArgs, options::OPT_fmodules_ignore_macro);
   Args.AddLastArg(CmdArgs, options::OPT_fmodules_prune_interval);
   Args.AddLastArg(CmdArgs, options::OPT_fmodules_prune_after);
 
+  if (HaveClangModules) {
     Args.AddLastArg(CmdArgs, options::OPT_fbuild_session_timestamp);
 
     if (Arg *A = Args.getLastArg(options::OPT_fbuild_session_file)) {
       if (Args.hasArg(options::OPT_fbuild_session_timestamp))
         D.Diag(diag::err_drv_argument_not_allowed_with)
             << A->getAsString(Args) << "-fbuild-session-timestamp";
 
       llvm::sys::fs::file_status Status;
       if (llvm::sys::fs::status(A->getValue(), Status))
         D.Diag(diag::err_drv_no_such_file) << A->getValue();
       CmdArgs.push_back(Args.MakeArgString(
           "-fbuild-session-timestamp=" +
           Twine((uint64_t)std::chrono::duration_cast<std::chrono::seconds>(
                     Status.getLastModificationTime().time_since_epoch())
                     .count())));
     }
 
-  if (Args.getLastArg(options::OPT_fmodules_validate_once_per_build_session)) {
+    if (Args.getLastArg(
+            options::OPT_fmodules_validate_once_per_build_session)) {
       if (!Args.getLastArg(options::OPT_fbuild_session_timestamp,
                            options::OPT_fbuild_session_file))
         D.Diag(diag::err_drv_modules_validate_once_requires_timestamp);
 
       Args.AddLastArg(CmdArgs,
                       options::OPT_fmodules_validate_once_per_build_session);
     }
 
     if (Args.hasFlag(options::OPT_fmodules_validate_system_headers,
                      options::OPT_fno_modules_validate_system_headers,
                      ImplicitModules))
       CmdArgs.push_back("-fmodules-validate-system-headers");
 
-  Args.AddLastArg(CmdArgs, options::OPT_fmodules_disable_diagnostic_validation);
+    Args.AddLastArg(CmdArgs,
+                    options::OPT_fmodules_disable_diagnostic_validation);
+  } else {
+    Args.ClaimAllArgs(options::OPT_fbuild_session_timestamp);
+    Args.ClaimAllArgs(options::OPT_fbuild_session_file);
+    Args.ClaimAllArgs(options::OPT_fmodules_validate_once_per_build_session);
+    Args.ClaimAllArgs(options::OPT_fmodules_validate_system_headers);
+    Args.ClaimAllArgs(options::OPT_fno_modules_validate_system_headers);
+    Args.ClaimAllArgs(options::OPT_fmodules_disable_diagnostic_validation);
+  }
 }
 
 static void RenderCharacterOptions(const ArgList &Args, const llvm::Triple &T,
                                    ArgStringList &CmdArgs) {
   // -fsigned-char is default.
   if (const Arg *A = Args.getLastArg(options::OPT_fsigned_char,
                                      options::OPT_fno_signed_char,
                                      options::OPT_funsigned_char,

clang/test/Driver/modules.m

 // RUN: %clang -fmodules -fno-modules -### %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MODULES %s
 // CHECK-NO-MODULES-NOT: -fmodules
 
 // RUN: %clang -fmodules -fno-modules -fmodules -### %s 2>&1 | FileCheck -check-prefix=CHECK-HAS-MODULES %s
 // CHECK-HAS-MODULES: -fmodules
 
-// RUN: %clang -fbuild-session-file=doesntexist -### %s 2>&1 | FileCheck -check-prefix=NOFILE %s
+// RUN: %clang -fmodules -fbuild-session-file=doesntexist -### %s 2>&1 | FileCheck -check-prefix=NOFILE %s
 // NOFILE: no such file or directory: 'doesntexist'
 
 // RUN: touch -m -a -t 201008011501 %t.build-session-file
-// RUN: %clang -fbuild-session-file=%t.build-session-file -### %s 2>&1 | FileCheck -check-prefix=TIMESTAMP_ONLY %s
+// RUN: %clang -fmodules -fbuild-session-file=%t.build-session-file -### %s 2>&1 | FileCheck -check-prefix=TIMESTAMP_ONLY %s
 
-// RUN: %clang -fbuild-session-timestamp=1280703457 -### %s 2>&1 | FileCheck -check-prefix=TIMESTAMP_ONLY %s
+// RUN: %clang -fmodules -fbuild-session-timestamp=1280703457 -### %s 2>&1 | FileCheck -check-prefix=TIMESTAMP_ONLY %s
 // TIMESTAMP_ONLY: -fbuild-session-timestamp=128{{([[:digit:]]{7})[^[:digit:]]}}
 
-// RUN: %clang -fbuild-session-file=%t.build-session-file -fbuild-session-timestamp=123 -### %s 2>&1 | FileCheck -check-prefix=CONFLICT %s
+// RUN: %clang -fmodules -fbuild-session-file=%t.build-session-file -fbuild-session-timestamp=123 -### %s 2>&1 | FileCheck -check-prefix=CONFLICT %s
 // CONFLICT: error: invalid argument '-fbuild-session-file={{.*}}.build-session-file' not allowed with '-fbuild-session-timestamp'
 
-// RUN: %clang -fbuild-session-timestamp=123 -fmodules-validate-once-per-build-session -### %s 2>&1 | FileCheck -check-prefix=MODULES_VALIDATE_ONCE %s
+// RUN: %clang -fmodules -fbuild-session-timestamp=123 -fmodules-validate-once-per-build-session -### %s 2>&1 | FileCheck -check-prefix=MODULES_VALIDATE_ONCE %s
 // MODULES_VALIDATE_ONCE: -fbuild-session-timestamp=123
 // MODULES_VALIDATE_ONCE: -fmodules-validate-once-per-build-session
 
-// RUN: %clang -fbuild-session-file=%t.build-session-file -fmodules-validate-once-per-build-session -### %s 2>&1 | FileCheck -check-prefix=MODULES_VALIDATE_ONCE_FILE %s
+// RUN: %clang -fmodules -fbuild-session-file=%t.build-session-file -fmodules-validate-once-per-build-session -### %s 2>&1 | FileCheck -check-prefix=MODULES_VALIDATE_ONCE_FILE %s
 // MODULES_VALIDATE_ONCE_FILE: -fbuild-session-timestamp=128{{([[:digit:]]{7})[^[:digit:]]}}
 // MODULES_VALIDATE_ONCE_FILE: -fmodules-validate-once-per-build-session
 
-// RUN: %clang -fmodules-validate-once-per-build-session -### %s 2>&1 | FileCheck -check-prefix=MODULES_VALIDATE_ONCE_ERR %s
+// RUN: %clang -fmodules -fmodules-validate-once-per-build-session -### %s 2>&1 | FileCheck -check-prefix=MODULES_VALIDATE_ONCE_ERR %s
 // MODULES_VALIDATE_ONCE_ERR: option '-fmodules-validate-once-per-build-session' requires '-fbuild-session-timestamp=<seconds since Epoch>' or '-fbuild-session-file=<file>'
 
 // RUN: %clang -### %s 2>&1 | FileCheck -check-prefix=MODULES_VALIDATE_SYSTEM_HEADERS_DEFAULT %s
 // MODULES_VALIDATE_SYSTEM_HEADERS_DEFAULT-NOT: -fmodules-validate-system-headers
 
 // RUN: %clang -fmodules -fsyntax-only -### %s 2>&1 | FileCheck -check-prefix=MODULES_VALIDATE_SYSTEM_HEADERS_DEFAULT_MOD %s
 // MODULES_VALIDATE_SYSTEM_HEADERS_DEFAULT_MOD: -fmodules-validate-system-headers
 
-// RUN: %clang -fmodules-validate-system-headers -### %s 2>&1 | FileCheck -check-prefix=MODULES_VALIDATE_SYSTEM_HEADERS %s
+// RUN: %clang -fmodules -fmodules-validate-system-headers -### %s 2>&1 | FileCheck -check-prefix=MODULES_VALIDATE_SYSTEM_HEADERS %s
 // MODULES_VALIDATE_SYSTEM_HEADERS: -fmodules-validate-system-headers
 
-// RUN: %clang -fno-modules-validate-system-headers -### %s 2>&1 | FileCheck -check-prefix=MODULES_VALIDATE_SYSTEM_HEADERS_NOSYSVALID %s
+// RUN: %clang -fmodules -fno-modules-validate-system-headers -### %s 2>&1 | FileCheck -check-prefix=MODULES_VALIDATE_SYSTEM_HEADERS_NOSYSVALID %s
 // MODULES_VALIDATE_SYSTEM_HEADERS_NOSYSVALID-NOT: -fmodules-validate-system-headers
 
 // RUN: %clang -### %s 2>&1 | FileCheck -check-prefix=MODULES_DISABLE_DIAGNOSTIC_VALIDATION_DEFAULT %s
 // MODULES_DISABLE_DIAGNOSTIC_VALIDATION_DEFAULT-NOT: -fmodules-disable-diagnostic-validation
 
-// RUN: %clang -fmodules-disable-diagnostic-validation -### %s 2>&1 | FileCheck -check-prefix=MODULES_DISABLE_DIAGNOSTIC_VALIDATION %s
+// RUN: %clang -fmodules -fmodules-disable-diagnostic-validation -### %s 2>&1 | FileCheck -check-prefix=MODULES_DISABLE_DIAGNOSTIC_VALIDATION %s
 // MODULES_DISABLE_DIAGNOSTIC_VALIDATION: -fmodules-disable-diagnostic-validation
 
 // RUN: %clang -fmodules -### %s 2>&1 | FileCheck -check-prefix=MODULES_PREBUILT_PATH_DEFAULT %s
 // MODULES_PREBUILT_PATH_DEFAULT-NOT: -fprebuilt-module-path
 
 // RUN: %clang -fmodules -fprebuilt-module-path=foo -fprebuilt-module-path=bar -### %s 2>&1 | FileCheck -check-prefix=MODULES_PREBUILT_PATH %s
 // MODULES_PREBUILT_PATH: "-fprebuilt-module-path=foo"
 // MODULES_PREBUILT_PATH: "-fprebuilt-module-path=bar"

 // CHECK-MODULE-FILES: "-fmodules"
 // CHECK-MODULE-FILES: "-fmodule-file=foo.pcm"
 // CHECK-MODULE-FILES: "-fmodule-file=bar.pcm"
 
 // RUN: %clang -fno-modules -fmodule-file=foo.pcm -fmodule-file=bar.pcm -### %s 2>&1 | FileCheck -check-prefix=CHECK-NO-MODULE-FILES %s
 // CHECK-NO-MODULE-FILES-NOT: "-fmodules"
 // CHECK-NO-MODULE-FILES-NOT: "-fmodule-file=foo.pcm"
 // CHECK-NO-MODULE-FILES-NOT: "-fmodule-file=bar.pcm"
+
+// RUN: %clang -fno-modules -fbuild-session-file=%t.build-session-file -### %s 2>&1 | FileCheck -check-prefix=SESSION_FLAG %s
+// RUN: %clang -fno-modules -fbuild-session-timestamp=123 -### %s 2>&1 | FileCheck -check-prefix=SESSION_FLAG %s
+// SESSION_FLAG-NOT: -fbuild-session-timestamp
+
+// RUN: %clang -fno-modules -fmodules-validate-once-per-build-session -### %s 2>&1 | FileCheck -check-prefix=VALIDATE_ONCE_FLAG %s
+// VALIDATE_ONCE_FLAG-NOT: -fmodules-validate-once-per-build-session
+
+// RUN: %clang -fno-modules -fmodules-validate-system-headers -### %s 2>&1 | FileCheck -check-prefix=VALIDATE_SYSTEM_FLAG %s
+// VALIDATE_SYSTEM_FLAG-NOT: -fmodules-validate-system-headers