[Modules] Do not emit relocation error when -fno-validate-pch is set

[yamaguchi]

Summary

Clang emits error when implicit modules was relocated from the
first build directory. However this was biting our usecase where we copy
the contents of build directory to another directory in order to
distribute.

cfe/trunk/lib/Serialization/ASTReader.cpp

case MODULE_DIRECTORY: {
       // If we've already loaded a module map file covering this module, we may
       // have a better path for it (relative to the current build).
       Module *M = PP.getHeaderSearchInfo().lookupModule(
           F.ModuleName, /*AllowSearch*/ true,
           /*AllowExtraModuleMapSearch*/ true);
       if (M && M->Directory) {
         // If we're implicitly loading a module, the base directory can't
         // change between the build and use.
-        if (F.Kind != MK_ExplicitModule && F.Kind != MK_PrebuiltModule) {
+        // Don't emit module relocation error if we have -fno-validate-pch
+        if (!PP.getPreprocessorOpts().DisablePCHValidation &&
+            F.Kind != MK_ExplicitModule && F.Kind != MK_PrebuiltModule) {
           const DirectoryEntry *BuildDir =
               PP.getFileManager().getDirectory(Blob);
           if (!BuildDir || BuildDir != M->Directory) {
             if ((ClientLoadCapabilities & ARR_OutOfDate) == 0)
               Diag(diag::err_imported_module_relocated)
                   << F.ModuleName << Blob << M->Directory->getName();
             return OutOfDate;
           }
ASTReader::ReadModuleMapFileBlock(RecordData &Record, ModuleFile &F,
   assert(!F.ModuleName.empty() &&
          "MODULE_NAME should come before MODULE_MAP_FILE");
   if (F.Kind == MK_ImplicitModule && ModuleMgr.begin()->Kind != MK_MainFile) {
     // An implicitly-loaded module file should have its module listed in some
     // module map file that we've already loaded.
     Module *M = PP.getHeaderSearchInfo().lookupModule(F.ModuleName);
     auto &Map = PP.getHeaderSearchInfo().getModuleMap();
     const FileEntry *ModMap = M ? Map.getModuleMapFileForUniquing(M) : nullptr;
-    if (!ModMap) {
+    // Don't emit module relocation error if we have -fno-validate-pch
+    if (!PP.getPreprocessorOpts().DisablePCHValidation && !ModMap) {
       assert(ImportedBy && "top-level import should be verified");
       if ((ClientLoadCapabilities & ARR_OutOfDate) == 0) {
         if (auto *ASTFE = M ? M->getASTFile() : nullptr) {
           // This module was defined by an imported (explicit) module.
           Diag(diag::err_module_file_conflict) << F.ModuleName << F.FileName
                                                << ASTFE->getName();
         } else {
           // This module was built with a different module map.
case SUBMODULE_DEFINITION: {
       if (GlobalIndex >= SubmodulesLoaded.size() ||
           SubmodulesLoaded[GlobalIndex]) {
         Error("too many submodules");
         return Failure;
       }
 
       if (!ParentModule) {
         if (const FileEntry *CurFile = CurrentModule->getASTFile()) {
-          if (CurFile != F.File) {
+          // Don't emit module relocation error if we have -fno-validate-pch
+          if (!PP.getPreprocessorOpts().DisablePCHValidation &&
+              CurFile != F.File) {
             if (!Diags.isDiagnosticInFlight()) {
               Diag(diag::err_module_file_conflict)
                 << CurrentModule->getTopLevelModuleName()
                 << CurFile->getName()
                 << F.File->getName();
             }
             return Failure;
           }

cfe/trunk/test/Modules/resolution-change.m

 // Use the PCH with no way to resolve A
 // RUN: not %clang_cc1 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -I %S/Inputs/modules-with-same-name/DependsOnA -include-pch %t-A.pch %s -fsyntax-only 2>&1 | FileCheck -check-prefix=CHECK-NOA %s
 // CHECK-NOA: module 'A' in AST file '{{.*A.*pcm}}' (imported by AST file '{{.*DependsOnA.*pcm}}') is not defined in any loaded module map
 
 // Use the PCH and have it resolve to the other A
 // RUN: not %clang_cc1 -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -I %S/Inputs/modules-with-same-name/DependsOnA -I %S/Inputs/modules-with-same-name/path2/A -include-pch %t-A.pch %s -fsyntax-only 2>&1 | FileCheck -check-prefix=CHECK-WRONGA %s
 // CHECK-WRONGA: module 'A' was built in directory '{{.*Inputs.modules-with-same-name.path1.A}}' but now resides in directory '{{.*Inputs.modules-with-same-name.path2.A}}'
 
+// RUN: %clang_cc1 -fno-validate-pch -fmodules -fimplicit-module-maps -fmodules-cache-path=%t -I %S/Inputs/modules-with-same-name/DependsOnA -I %S/Inputs/modules-with-same-name/path2/A -include-pch %t-A.pch %s -fsyntax-only
+
 #ifndef HEADER
 #define HEADER
 @import DependsOnA;
 #endif