[modules] If we import a module, and we've seen a module map that describes the

module, use the path from the module map file in preference to the path from
the .pcm file when resolving relative paths in the .pcm file. This allows
diagnostics (and .d output) to give relative paths if the module was found via
a relative path.

llvm-svn: 223577

clang/include/clang/Basic/DiagnosticSerializationKinds.td

@@ -58,6 +58,9 @@ def err_imported_module_not_found : Error<
 def err_imported_module_modmap_changed : Error<
     "module '%0' imported by AST file '%1' found in a different module map file"
     " (%2) than when the importing AST file was built (%3)">, DefaultFatal;
+def err_imported_module_relocated : Error<
+    "module '%0' was built in directory '%1' but now resides in "
+    "directory '%2'">, DefaultFatal;
 def err_module_different_modmap : Error<
     "module '%0' %select{uses|does not use}1 additional module map '%2'"
     "%select{| not}1 used when the module was built">;

clang/lib/Serialization/ASTReader.cpp

@@ -2508,9 +2508,31 @@ ASTReader::ReadControlBlock(ModuleFile &F,
         Listener->ReadModuleName(F.ModuleName);
       break;
 
-    case MODULE_DIRECTORY:
-      F.BaseDirectory = Blob;
+    case MODULE_DIRECTORY: {
+      assert(!F.ModuleName.empty() &&
+             "MODULE_DIRECTORY found before MODULE_NAME");
+      // 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);
+      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) {
+          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;
+          }
+        }
+        F.BaseDirectory = M->Directory->getName();
+      } else {
+        F.BaseDirectory = Blob;
+      }
       break;
+    }
 
     case MODULE_MAP_FILE:
       if (ASTReadResult Result =

clang/test/Modules/Inputs/malformed/c.h

@@ -0,0 +1 @@
+template<typename T> void f() { T::error; }

clang/test/Modules/Inputs/malformed/module.map

@@ -6,3 +6,4 @@ module malformed_b {
   module b1 { header "b1.h" }
   module b2 { header "b2.h" }
 }
+module c { header "c.h" }

clang/test/Modules/Inputs/relative-dep-gen.modulemap

@@ -0,0 +1,4 @@
+module "relative-dep-gen" {
+  header "relative-dep-gen-1.h"
+  header "relative-dep-gen-2.h"
+}

clang/test/Modules/malformed.cpp

@@ -7,6 +7,7 @@
 // RUN: cd %S
 // RUN: not %clang_cc1 -fmodules -fmodules-cache-path=%t -I Inputs/malformed -DHEADER="a1.h" %s 2>&1 | FileCheck %s --check-prefix=CHECK-A
 // RUN: not %clang_cc1 -fmodules -fmodules-cache-path=%t -I Inputs/malformed -DHEADER="b1.h" %s 2>&1 | FileCheck %s --check-prefix=CHECK-B
+// RUN: not %clang_cc1 -fmodules -fmodules-cache-path=%t -I Inputs/malformed -DHEADER="c.h" malformed.cpp 2>&1 | FileCheck %s --check-prefix=CHECK-C
 
 #define STR2(x) #x
 #define STR(x) STR2(x)
@@ -27,3 +28,10 @@
 // CHECK-B: While building module 'malformed_b'
 // CHECK-B: {{^}}Inputs/malformed/b2.h:1:{{.*}} error: redefinition of 'g'
 // CHECK-B: {{^}}Inputs/malformed/b2.h:1:{{.*}} note: previous definition is here
+
+void test() { f<int>(); }
+// Test that we use relative paths to name files within an imported module.
+//
+// CHECK-C: In module 'c' imported from malformed.cpp:14:
+// CHECK-C: {{^}}Inputs/malformed/c.h:1:33: error: type 'int' cannot be used prior to '::'
+// CHECK-C: {{^}}malformed.cpp:[[@LINE-5]]:15: note: in instantiation of

clang/test/Modules/relative-dep-gen.cpp

@@ -0,0 +1,17 @@
+// REQUIRES: shell
+//
+// RUN: cd %S
+// RUN: rm -rf %t
+// RUN: mkdir %t
+// RUN: %clang_cc1 -cc1 -fmodule-name=relative-dep-gen -emit-module -x c++ Inputs/relative-dep-gen.modulemap -dependency-file %t/build.d -MT mod.pcm -o %t/mod.pcm
+// RUN: %clang_cc1 -cc1 -fmodule-map-file=Inputs/relative-dep-gen.modulemap -fmodule-file=%t/mod.pcm -dependency-file %t/use-explicit.d -MT use.o relative-dep-gen.cpp -fsyntax-only
+// RUN: %clang_cc1 -cc1 -fmodule-map-file=Inputs/relative-dep-gen.modulemap -dependency-file %t/use-implicit.d relative-dep-gen.cpp -MT use.o -fsyntax-only
+//
+// RUN: FileCheck --check-prefix=CHECK-BUILD %s < %t/build.d
+// RUN: FileCheck --check-prefix=CHECK-USE %s < %t/use-explicit.d
+// RUN: FileCheck --check-prefix=CHECK-USE %s < %t/use-implicit.d
+
+#include "Inputs/relative-dep-gen-1.h"
+
+// CHECK-BUILD: mod.pcm: Inputs/relative-dep-gen-1.h Inputs/relative-dep-gen-2.h
+// CHECK-USE: use.o: relative-dep-gen.cpp Inputs/relative-dep-gen-1.h

clang/test/Modules/resolution-change.m

@@ -17,9 +17,9 @@
 // RUN: not %clang_cc1 -fmodules -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 the the other A
+// Use the PCH and have it resolve to the other A
 // RUN: not %clang_cc1 -fmodules -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' imported by AST file '{{.*DependsOnA.*pcm}}' found in a different module map file ({{.*path2.*}}) than when the importing AST file was built ({{.*path1.*}})
+// 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}}'
 
 #ifndef HEADER
 #define HEADER