[ExplicitModule] Propagate deterministic check to explicit modules

Make `-enable-deterministic-check` a driver option and teach dependency
scanner to propagate the option to explicit module build commmands. This
allows to the option to check every build output from the compiler is
deterministic.

Author: cachemeifyoucan

include/swift/Option/FrontendOptions.td

@@ -1425,9 +1425,6 @@ def enable_emit_generic_class_ro_t_list :
   HelpText<"Enable emission of a section with references to class_ro_t of "
            "generic class patterns">;
 
-def enable_deterministic_check :
-  Flag<["-"], "enable-deterministic-check">,
-  HelpText<"Check compiler output determinism by running it twice">;
 def always_compile_output_files :
   Flag<["-"], "always-compile-output-files">,
   HelpText<"Always compile output files even it might not change the results">;

include/swift/Option/Options.td

@@ -2245,4 +2245,9 @@ def disable_sandbox:
   Flags<[FrontendOption, DoesNotAffectIncrementalBuild]>,
   HelpText<"Disable using the sandbox when executing subprocesses">;
 
+def enable_deterministic_check :
+  Flag<["-"], "enable-deterministic-check">,
+  Flags<[FrontendOption, DoesNotAffectIncrementalBuild, CacheInvariant]>,
+  HelpText<"Check compiler output determinism by running it twice">;
+
 include "FrontendOptions.td"

lib/DependencyScan/ScanDependencies.cpp

@@ -167,6 +167,7 @@ class ExplicitModuleDependencyResolver {
           bridgingHeaderBuildCmd.push_back(clangDep->moduleCacheKey);
         }
       }
+      addDeterministicCheckFlags(bridgingHeaderBuildCmd);
     }
 
     SwiftInterfaceModuleOutputPathResolution::ResultTy swiftInterfaceOutputPath;
@@ -183,6 +184,7 @@ class ExplicitModuleDependencyResolver {
             remapPathsFromCommandLine(commandline, [&](StringRef path) {
               return cache.getScanService().remapPath(path);
             });
+      addDeterministicCheckFlags(commandline);
     }
 
     auto dependencyInfoCopy = resolvingDepInfo;
@@ -583,6 +585,17 @@ class ExplicitModuleDependencyResolver {
     return llvm::Error::success();
   }
 
+  void addDeterministicCheckFlags(std::vector<std::string> &cmd) {
+    // Propagate the deterministic check to explicit built module command.
+    if (!instance.getInvocation().getFrontendOptions().DeterministicCheck)
+      return;
+    cmd.push_back("-enable-deterministic-check");
+    cmd.push_back("-always-compile-output-files");
+    // disable cache replay because that defeat the purpose of the check.
+    if (instance.getInvocation().getCASOptions().EnableCaching)
+      cmd.push_back("-cache-disable-replay");
+  }
+
 private:
   const ModuleDependencyID &moduleID;
   ModuleDependenciesCache &cache;

test/CAS/deterministic_check.swift

@@ -0,0 +1,43 @@
+// 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 -module-load-mode prefer-serialized \
+// RUN:   %t/test.swift -o %t/deps.json -I %t -import-objc-header %t/Bridging.h \
+// RUN:   -enable-deterministic-check -cache-compile-job -cas-path %t/cas 2>&1 | %FileCheck %s
+
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json A > %t/A.cmd
+// RUN: %FileCheck %s --check-prefix=CMD --input-file=%t/A.cmd
+// RUN: %swift_frontend_plain @%t/A.cmd 2>&1 | %FileCheck %s
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:B > %t/B.cmd
+// RUN: %FileCheck %s --check-prefix=CMD --input-file=%t/B.cmd
+// RUN: %swift_frontend_plain @%t/B.cmd 2>&1 | %FileCheck %s
+
+// RUN: %{python} %S/Inputs/SwiftDepsExtractor.py %t/deps.json Test bridgingHeader | %FileCheck %s --check-prefix=CMD
+
+// CHECK: remark: produced matching output file
+// CMD: -enable-deterministic-check
+// CMD: -always-compile-output-files
+// CMD: -cache-disable-replay
+
+//--- test.swift
+import A
+import B
+public func test() {}
+
+//--- A.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name A -O -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib -user-module-version 1.0
+public func a() { }
+
+//--- b.h
+void b(void);
+
+//--- module.modulemap
+module B {
+  header "b.h"
+  export *
+}
+
+//--- Bridging.h
+void bridge(void);

test/ScanDependencies/deterministic_check.swift

@@ -0,0 +1,36 @@
+// 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 -module-load-mode prefer-serialized \
+// RUN:   %t/test.swift -o %t/deps.json -I %t -enable-deterministic-check 2>&1 | %FileCheck %s
+
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json A > %t/A.cmd
+// RUN: %FileCheck %s --check-prefix=CMD --input-file=%t/A.cmd
+// RUN: %swift_frontend_plain @%t/A.cmd 2>&1 | %FileCheck %s
+// RUN: %{python} %S/../CAS/Inputs/BuildCommandExtractor.py %t/deps.json clang:B > %t/B.cmd
+// RUN: %FileCheck %s --check-prefix=CMD --input-file=%t/B.cmd
+// RUN: %swift_frontend_plain @%t/B.cmd 2>&1 | %FileCheck %s
+
+// CHECK: remark: produced matching output file
+// CMD: -enable-deterministic-check
+// CMD: -always-compile-output-files
+
+//--- test.swift
+import A
+import B
+public func test() {}
+
+//--- A.swiftinterface
+// swift-interface-format-version: 1.0
+// swift-module-flags: -module-name A -O -disable-implicit-string-processing-module-import -disable-implicit-concurrency-module-import -parse-stdlib -user-module-version 1.0
+public func a() { }
+
+//--- b.h
+void b(void);
+
+//--- module.modulemap
+module B {
+  header "b.h"
+  export *
+}