[clang][cli] Specify correct integer width for -fbuild-session-timestamp

[jansvoboda11]

Summary

This fixes an issue where large integer values were rejected as invalid.

clang/include/clang/Driver/Options.td

def fmodules_prune_after : Joined<["-"], "fmodules-prune-after=">, Group<i_Group>,
   HelpText<"Specify the interval (in seconds) after which a module file will be considered unused">,
   MarshallingInfoStringInt<"HeaderSearchOpts->ModuleCachePruneAfter", "31 * 24 * 60 * 60">;
 def fmodules_search_all : Flag <["-"], "fmodules-search-all">, Group<f_Group>,
   Flags<[NoXarchOption, CC1Option]>,
   HelpText<"Search even non-imported modules to resolve references">;
 def fbuild_session_timestamp : Joined<["-"], "fbuild-session-timestamp=">,
   Group<i_Group>, Flags<[CC1Option]>, MetaVarName<"<time since Epoch in seconds>">,
   HelpText<"Time when the current build session started">,
-  MarshallingInfoStringInt<"HeaderSearchOpts->BuildSessionTimestamp">;
+  MarshallingInfoStringInt<"HeaderSearchOpts->BuildSessionTimestamp", "0", "uint64_t">;
 def fbuild_session_file : Joined<["-"], "fbuild-session-file=">,
   Group<i_Group>, MetaVarName<"<file>">,
   HelpText<"Use the last modification time of <file> as the build session timestamp">;
 def fmodules_validate_once_per_build_session : Flag<["-"], "fmodules-validate-once-per-build-session">,
   Group<i_Group>, Flags<[CC1Option]>,
   HelpText<"Don't verify input files for the modules if the module has been "
            "successfully validated or loaded during this build session">,
   MarshallingInfoFlag<"HeaderSearchOpts->ModulesValidateOncePerBuildSession">;

clang/unittests/Frontend/CompilerInvocationTest.cpp

 //===- unittests/Frontend/CompilerInvocationTest.cpp - CI tests //---------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
TEST_F(CommandLineTest, CanGenerateCC1COmmandLineSeparateEnumDefault) {
   ASSERT_FALSE(Diags->hasErrorOccurred());
 
   Invocation.generateCC1CommandLine(GeneratedArgs, *this);
 
   // Default relocation model.
   ASSERT_THAT(GeneratedArgs, Not(Contains(StrEq("pic"))));
 }
 
+// Wide integer option.
+
+TEST_F(CommandLineTest, WideIntegerHighValue) {
+  const char *Args[] = {"-fbuild-session-timestamp=1609827494445723662"};
+
+  CompilerInvocation::CreateFromArgs(Invocation, Args, *Diags);
+
+  ASSERT_FALSE(Diags->hasErrorOccurred());
+  ASSERT_EQ(Invocation.getHeaderSearchOpts().BuildSessionTimestamp,
+            1609827494445723662ull);
+}
+
 // Tree of boolean options that can be (directly or transitively) implied by
 // their parent:
 //
 //   * -cl-unsafe-math-optimizations
 //     * -cl-mad-enable
 //     * -menable-unsafe-fp-math
 //       * -freciprocal-math