Add an option -fmodules-validate-system-headers

When enabled, always validate the system headers when loading a module.
The end result of this is that when these headers change, we will notice
and rebuild the module.

llvm-svn: 203630

7 files changed, 49 insertions, 4 deletions

diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index b3dd5c3b906..fd8b823d0b3 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -591,6 +591,9 @@ def fmodules_validate_once_per_build_session : Flag<["-"], "fmodules-validate-on
   Group<i_Group>, Flags<[CC1Option]>,
   HelpText<"Don't verify input files for the modules if the module has been "
            "successfully validate or loaded during this build session">;
+def fmodules_validate_system_headers : Flag<["-"], "fmodules-validate-system-headers">,
+  Group<i_Group>, Flags<[CC1Option]>,
+  HelpText<"Validate the system headers that a module depends on when loading the module">;
 def fmodules : Flag <["-"], "fmodules">, Group<f_Group>,
   Flags<[DriverOption, CC1Option]>,
   HelpText<"Enable the 'modules' language feature">;
diff --git a/clang/include/clang/Lex/HeaderSearchOptions.h b/clang/include/clang/Lex/HeaderSearchOptions.h
index 53b4bdc4c9f..06024b2e90f 100644
--- a/clang/include/clang/Lex/HeaderSearchOptions.h
+++ b/clang/include/clang/Lex/HeaderSearchOptions.h
@@ -155,6 +155,9 @@ public:
   /// \c BuildSessionTimestamp).
   unsigned ModulesValidateOncePerBuildSession : 1;
 
+  /// \brief Whether to validate system input files when a module is loaded.
+  unsigned ModulesValidateSystemHeaders : 1;
+
 public:
   HeaderSearchOptions(StringRef _Sysroot = "/")
     : Sysroot(_Sysroot), DisableModuleHash(0), ModuleMaps(0),
@@ -164,7 +167,8 @@ public:
       UseBuiltinIncludes(true),
       UseStandardSystemIncludes(true), UseStandardCXXIncludes(true),
       UseLibcxx(false), Verbose(false),
-      ModulesValidateOncePerBuildSession(false) {}
+      ModulesValidateOncePerBuildSession(false),
+      ModulesValidateSystemHeaders(false) {}
 
   /// AddPath - Add the \p Path path to the specified \p Group list.
   void AddPath(StringRef Path, frontend::IncludeDirGroup Group,
diff --git a/clang/lib/Driver/Tools.cpp b/clang/lib/Driver/Tools.cpp
index 537390a7da3..cc944885ad4 100644
--- a/clang/lib/Driver/Tools.cpp
+++ b/clang/lib/Driver/Tools.cpp
@@ -3390,6 +3390,8 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
                     options::OPT_fmodules_validate_once_per_build_session);
   }
 
+  Args.AddLastArg(CmdArgs, options::OPT_fmodules_validate_system_headers);
+
   // -faccess-control is default.
   if (Args.hasFlag(options::OPT_fno_access_control,
                    options::OPT_faccess_control,
diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
index 11b5ba9f549..ce47674edbc 100644
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -334,13 +334,15 @@ CompilerInstance::createPCHExternalASTSource(StringRef Path,
                                              void *DeserializationListener,
                                              bool Preamble,
                                              bool UseGlobalModuleIndex) {
+  HeaderSearchOptions &HSOpts = PP.getHeaderSearchInfo().getHeaderSearchOpts();
+
   std::unique_ptr<ASTReader> Reader;
   Reader.reset(new ASTReader(PP, Context,
                              Sysroot.empty() ? "" : Sysroot.c_str(),
                              DisablePCHValidation,
                              AllowPCHWithCompilerErrors,
                              /*AllowConfigurationMismatch*/false,
-                             /*ValidateSystemInputs*/false,
+                             HSOpts.ModulesValidateSystemHeaders,
                              UseGlobalModuleIndex));
 
   Reader->setDeserializationListener(
@@ -1141,14 +1143,15 @@ CompilerInstance::loadModule(SourceLocation ImportLoc,
         pruneModuleCache(getHeaderSearchOpts());
       }
 
-      std::string Sysroot = getHeaderSearchOpts().Sysroot;
+      HeaderSearchOptions &HSOpts = getHeaderSearchOpts();
+      std::string Sysroot = HSOpts.Sysroot;
       const PreprocessorOptions &PPOpts = getPreprocessorOpts();
       ModuleManager = new ASTReader(getPreprocessor(), *Context,
                                     Sysroot.empty() ? "" : Sysroot.c_str(),
                                     PPOpts.DisablePCHValidation,
                                     /*AllowASTWithCompilerErrors=*/false,
                                     /*AllowConfigurationMismatch=*/false,
-                                    /*ValidateSystemInputs=*/false,
+                                    HSOpts.ModulesValidateSystemHeaders,
                                     getFrontendOpts().UseGlobalModuleIndex);
       if (hasASTConsumer()) {
         ModuleManager->setDeserializationListener(
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 20e59c2726c..f368837a5f0 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -930,6 +930,9 @@ static void ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args) {
       Args.hasArg(OPT_fmodules_validate_once_per_build_session);
   Opts.BuildSessionTimestamp =
       getLastArgUInt64Value(Args, OPT_fbuild_session_timestamp, 0);
+  Opts.ModulesValidateSystemHeaders =
+      Args.hasArg(OPT_fmodules_validate_system_headers);
+
   for (arg_iterator it = Args.filtered_begin(OPT_fmodules_ignore_macro),
                     ie = Args.filtered_end();
        it != ie; ++it) {
diff --git a/clang/test/Driver/modules.m b/clang/test/Driver/modules.m
index 7b14f21443f..d8e20e4148e 100644
--- a/clang/test/Driver/modules.m
+++ b/clang/test/Driver/modules.m
@@ -14,3 +14,8 @@
 // RUN: %clang -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>'
 
+// 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-validate-system-headers -### %s 2>&1 | FileCheck -check-prefix=MODULES_VALIDATE_SYSTEM_HEADERS %s
+// MODULES_VALIDATE_SYSTEM_HEADERS: -fmodules-validate-system-headers
diff --git a/clang/test/Modules/validate-system-headers.m b/clang/test/Modules/validate-system-headers.m
new file mode 100644
index 00000000000..9fb2bd2a637
--- /dev/null
+++ b/clang/test/Modules/validate-system-headers.m
@@ -0,0 +1,25 @@
+// RUN: rm -rf %t/ModuleCache
+// RUN: mkdir -p %t/Inputs/usr/include
+// RUN: touch %t/Inputs/usr/include/foo.h
+// RUN: echo 'module Foo [system] { header "foo.h" }' > %t/Inputs/usr/include/module.map
+
+////
+// Build a module using a system header
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -isysroot %t/Inputs -fmodules -fmodules-cache-path=%t/ModuleCache -fdisable-module-hash -x objective-c-header -fsyntax-only %s
+// RUN: cp %t/ModuleCache/Foo.pcm %t/Foo.pcm.saved
+
+////
+// Modify the system header, and confirm that we don't notice without -fmodules-validate-system-headers.
+// The pcm file in the cache should fail to validate.
+// RUN: echo ' ' >> %t/Inputs/usr/include/foo.h
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -isysroot %t/Inputs -fmodules -fmodules-cache-path=%t/ModuleCache -fdisable-module-hash -x objective-c-header -fsyntax-only %s
+// RUN: diff %t/ModuleCache/Foo.pcm %t/Foo.pcm.saved
+
+////
+// Now make sure we rebuild the module when -fmodules-validate-system-headers is set.
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -isysroot %t/Inputs -fmodules -fmodules-validate-system-headers -fmodules-cache-path=%t/ModuleCache -fdisable-module-hash -x objective-c-header -fsyntax-only %s
+// RUN: not diff %t/ModuleCache/Foo.pcm %t/Foo.pcm.saved
+
+// REQUIRES: shell
+
+@import Foo;