Modules: add command line option fmodules-disable-diagnostic-validation

With PCH+Module, sometimes compiler gives a hard error:
Module file ‘<some-file path>.pcm' is out of date and needs to be rebuilt

This happens when we have a pch importing a module and the module gets
overwritten by another compiler instance after we build the pch (one example is
that both compiler instances hash to the same pcm file but use different
diagnostic options). When we try to load the pch later on, the compiler notices
that the imported module is out of date (modification date, size do not match)
but it can't handle this out of date pcm (i.e it does not know how to rebuild
the pch).

This commit introduces a new command line option so for PCH + module, we can
turn on this option and if two compiler instances only differ in diagnostic
options, the latter instance will not invalidate the original pcm.

rdar://26675801
Differential Revision: http://reviews.llvm.org/D22773


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@276769 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Driver/Options.td

@@ -857,6 +857,9 @@ 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 validated or loaded during this build session">;
+def fmodules_disable_diagnostic_validation : Flag<["-"], "fmodules-disable-diagnostic-validation">,
+  Group<i_Group>, Flags<[CC1Option]>,
+  HelpText<"Disable validation of the diagnostic options when loading the module">;
 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">;

include/clang/Lex/HeaderSearchOptions.h

@@ -172,6 +172,8 @@ public:
   /// Whether the module includes debug information (-gmodules).
   unsigned UseDebugInfo : 1;
 
+  unsigned ModulesValidateDiagnosticOptions : 1;
+
   HeaderSearchOptions(StringRef _Sysroot = "/")
       : Sysroot(_Sysroot), ModuleFormat("raw"), DisableModuleHash(0),
         ImplicitModuleMaps(0), ModuleMapFileHomeIsCwd(0),
@@ -181,7 +183,7 @@ public:
         UseStandardCXXIncludes(true), UseLibcxx(false), Verbose(false),
         ModulesValidateOncePerBuildSession(false),
         ModulesValidateSystemHeaders(false),
-        UseDebugInfo(false) {}
+        UseDebugInfo(false), ModulesValidateDiagnosticOptions(true) {}
 
   /// AddPath - Add the \p Path path to the specified \p Group list.
   void AddPath(StringRef Path, frontend::IncludeDirGroup Group,

include/clang/Serialization/ASTReader.h

@@ -1153,7 +1153,7 @@ private:
   static ASTReadResult ReadOptionsBlock(
       llvm::BitstreamCursor &Stream, unsigned ClientLoadCapabilities,
       bool AllowCompatibleConfigurationMismatch, ASTReaderListener &Listener,
-      std::string &SuggestedPredefines);
+      std::string &SuggestedPredefines, bool ValidateDiagnosticOptions);
   ASTReadResult ReadASTBlock(ModuleFile &F, unsigned ClientLoadCapabilities);
   ASTReadResult ReadExtensionBlock(ModuleFile &F);
   bool ParseLineTable(ModuleFile &F, const RecordData &Record);
@@ -1516,7 +1516,8 @@ public:
   readASTFileControlBlock(StringRef Filename, FileManager &FileMgr,
                           const PCHContainerReader &PCHContainerRdr,
                           bool FindModuleFileExtensions,
-                          ASTReaderListener &Listener);
+                          ASTReaderListener &Listener,
+                          bool ValidateDiagnosticOptions);
 
   /// \brief Determine whether the given AST file is acceptable to load into a
   /// translation unit with the given language and target options.

lib/Frontend/CompilerInvocation.cpp

@@ -1362,6 +1362,8 @@ static void ParseHeaderSearchArgs(HeaderSearchOptions &Opts, ArgList &Args) {
   Opts.ModuleCachePath = Args.getLastArgValue(OPT_fmodules_cache_path);
   Opts.ModuleUserBuildPath = Args.getLastArgValue(OPT_fmodules_user_build_path);
   Opts.DisableModuleHash = Args.hasArg(OPT_fdisable_module_hash);
+  Opts.ModulesValidateDiagnosticOptions =
+      !Args.hasArg(OPT_fmodules_disable_diagnostic_validation);
   Opts.ImplicitModuleMaps = Args.hasArg(OPT_fimplicit_module_maps);
   Opts.ModuleMapFileHomeIsCwd = Args.hasArg(OPT_fmodule_map_file_home_is_cwd);
   Opts.ModuleCachePruneInterval =
@@ -2457,7 +2459,8 @@ std::string CompilerInvocation::getModuleHash() const {
                       hsOpts.UseBuiltinIncludes,
                       hsOpts.UseStandardSystemIncludes,
                       hsOpts.UseStandardCXXIncludes,
-                      hsOpts.UseLibcxx);
+                      hsOpts.UseLibcxx,
+                      hsOpts.ModulesValidateDiagnosticOptions);
   code = hash_combine(code, hsOpts.ResourceDir);
 
   // Extend the signature with the user build path.

lib/Frontend/FrontendActions.cpp

@@ -608,11 +608,15 @@ void DumpModuleInfoAction::ExecuteAction() {
   llvm::raw_ostream &Out = OutFile.get()? *OutFile.get() : llvm::outs();
 
   Out << "Information for module file '" << getCurrentFile() << "':\n";
+  Preprocessor &PP = getCompilerInstance().getPreprocessor();
   DumpModuleInfoListener Listener(Out);
+  HeaderSearchOptions &HSOpts =
+      PP.getHeaderSearchInfo().getHeaderSearchOpts();
   ASTReader::readASTFileControlBlock(
       getCurrentFile(), getCompilerInstance().getFileManager(),
       getCompilerInstance().getPCHContainerReader(),
-      /*FindModuleFileExtensions=*/true, Listener);
+      /*FindModuleFileExtensions=*/true, Listener,
+      HSOpts.ModulesValidateDiagnosticOptions);
 }
 
 //===----------------------------------------------------------------------===//

lib/Serialization/ASTReader.cpp

@@ -2084,7 +2084,7 @@ static bool isDiagnosedResult(ASTReader::ASTReadResult ARR, unsigned Caps) {
 ASTReader::ASTReadResult ASTReader::ReadOptionsBlock(
     BitstreamCursor &Stream, unsigned ClientLoadCapabilities,
     bool AllowCompatibleConfigurationMismatch, ASTReaderListener &Listener,
-    std::string &SuggestedPredefines) {
+    std::string &SuggestedPredefines, bool ValidateDiagnosticOptions) {
   if (Stream.EnterSubBlock(OPTIONS_BLOCK_ID))
     return Failure;
 
@@ -2128,7 +2128,8 @@ ASTReader::ASTReadResult ASTReader::ReadOptionsBlock(
 
     case DIAGNOSTIC_OPTIONS: {
       bool Complain = (ClientLoadCapabilities & ARR_OutOfDate) == 0;
-      if (!AllowCompatibleConfigurationMismatch &&
+      if (ValidateDiagnosticOptions &&
+          !AllowCompatibleConfigurationMismatch &&
           ParseDiagnosticOptions(Record, Complain, Listener))
         return OutOfDate;
       break;
@@ -2255,10 +2256,13 @@ ASTReader::ReadControlBlock(ModuleFile &F,
           // FIXME: Allow this for files explicitly specified with -include-pch.
           bool AllowCompatibleConfigurationMismatch =
               F.Kind == MK_ExplicitModule;
+          const HeaderSearchOptions &HSOpts =
+              PP.getHeaderSearchInfo().getHeaderSearchOpts();
 
           Result = ReadOptionsBlock(Stream, ClientLoadCapabilities,
                                     AllowCompatibleConfigurationMismatch,
-                                    *Listener, SuggestedPredefines);
+                                    *Listener, SuggestedPredefines,
+                                    HSOpts.ModulesValidateDiagnosticOptions);
           if (Result == Failure) {
             Error("malformed block record in AST file");
             return Result;
@@ -4195,7 +4199,7 @@ bool ASTReader::readASTFileControlBlock(
     StringRef Filename, FileManager &FileMgr,
     const PCHContainerReader &PCHContainerRdr,
     bool FindModuleFileExtensions,
-    ASTReaderListener &Listener) {
+    ASTReaderListener &Listener, bool ValidateDiagnosticOptions) {
   // Open the AST file.
   // FIXME: This allows use of the VFS; we do not allow use of the
   // VFS when actually loading a module.
@@ -4235,7 +4239,8 @@ bool ASTReader::readASTFileControlBlock(
         std::string IgnoredSuggestedPredefines;
         if (ReadOptionsBlock(Stream, ARR_ConfigurationMismatch | ARR_OutOfDate,
                              /*AllowCompatibleConfigurationMismatch*/ false,
-                             Listener, IgnoredSuggestedPredefines) != Success)
+                             Listener, IgnoredSuggestedPredefines,
+                             ValidateDiagnosticOptions) != Success)
           return true;
         break;
       }
@@ -4408,7 +4413,8 @@ bool ASTReader::isAcceptableASTFile(
                                ExistingModuleCachePath, FileMgr);
   return !readASTFileControlBlock(Filename, FileMgr, PCHContainerRdr,
                                   /*FindModuleFileExtensions=*/false,
-                                  validator);
+                                  validator,
+                                  /*ValidateDiagnosticOptions=*/true);
 }
 
 ASTReader::ASTReadResult

test/Driver/modules.m

@@ -33,6 +33,12 @@
 // 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
 
+// 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
+// MODULES_DISABLE_DIAGNOSTIC_VALIDATION: -fmodules-disable-diagnostic-validation
+
 // RUN: %clang -fmodules -fmodule-map-file=foo.map -fmodule-map-file=bar.map -### %s 2>&1 | FileCheck -check-prefix=CHECK-MODULE-MAP-FILES %s
 // CHECK-MODULE-MAP-FILES: "-fmodules"
 // CHECK-MODULE-MAP-FILES: "-fmodule-map-file=foo.map"

test/Modules/Inputs/DiagOutOfDate.h

@@ -0,0 +1 @@
+const int a = 1;

test/Modules/Inputs/module.map

@@ -418,3 +418,7 @@ module Empty {}
 module MacroFabs1 {
   header "MacroFabs1.h"
 }
+
+module DiagOutOfDate {
+  header "DiagOutOfDate.h"
+}

test/Modules/Inputs/pch-import-module-out-of-date.pch

@@ -0,0 +1 @@
+@import DiagOutOfDate;

test/Modules/diagnostic-options-out-of-date.m

@@ -0,0 +1,12 @@
+// RUN: rm -rf %t
+// Build A.pcm
+// RUN: %clang_cc1 -Werror -Wno-conversion -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -I %S/Inputs %s -fmodules-disable-diagnostic-validation
+// Build pch that imports A.pcm
+// RUN: %clang_cc1 -Werror -Wno-conversion -emit-pch -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -o %t.pch -I %S/Inputs -x objective-c-header %S/Inputs/pch-import-module-out-of-date.pch -fmodules-disable-diagnostic-validation
+// Make sure that we don't rebuild A.pcm and overwrite the original A.pcm that the pch imports
+// RUN: %clang_cc1 -Werror -Wconversion -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -I %S/Inputs %s -fmodules-disable-diagnostic-validation
+// Make sure we don't error out when using the pch
+// RUN: %clang_cc1 -Werror -Wno-conversion -fmodules-cache-path=%t -fmodules -fimplicit-module-maps -fsyntax-only -I %S/Inputs -include-pch %t.pch %s -verify -fmodules-disable-diagnostic-validation
+// expected-no-diagnostics
+
+@import DiagOutOfDate;