When we're emitting a diagnostic with a source location in an imported

module, provide a module import stack similar to what we would get for
an include stack, e.g.,

In module 'DependsOnModule' imported from build-fail-notes.m:4:
In module 'Module' imported from DependsOnModule.framework/Headers/DependsOnModule.h:1:
Inputs/Module.framework/Headers/Module.h:15:12: note: previous definition is here
@interface Module

<rdar://problem/12696425>


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@169042 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 41 insertions, 2 deletions

diff --git a/include/clang/Basic/SourceManager.h b/include/clang/Basic/SourceManager.h
index bd31c79ba2..d79cbfe5ae 100644
--- a/include/clang/Basic/SourceManager.h
+++ b/include/clang/Basic/SourceManager.h
@@ -430,6 +430,11 @@ public:
   /// \returns true if an error occurred that prevented the source-location
   /// entry from being loaded.
   virtual bool ReadSLocEntry(int ID) = 0;
+
+  /// \brief Retrieve the module import location and name for the given ID, if
+  /// in fact it was loaded from a module (rather than, say, a precompiled
+  /// header).
+  virtual std::pair<SourceLocation, StringRef> getModuleImportLoc(int ID) = 0;
 };
 
 
@@ -990,6 +995,21 @@ public:
     return Entry.getFile().getIncludeLoc();
   }
 
+  // \brief Returns the import location if the given source location is
+  // located within a module, or an invalid location if the source location
+  // is within the current translation unit.
+  std::pair<SourceLocation, StringRef>
+  getModuleImportLoc(SourceLocation Loc) const {
+    FileID FID = getFileID(Loc);
+
+    // Positive file IDs are in the current translation unit, and -1 is a
+    // placeholder.
+    if (FID.ID >= -1)
+      return std::make_pair(SourceLocation(), "");
+
+    return ExternalSLocEntries->getModuleImportLoc(FID.ID);
+  }
+
   /// \brief Given a SourceLocation object \p Loc, return the expansion
   /// location referenced by the ID.
   SourceLocation getExpansionLoc(SourceLocation Loc) const {
diff --git a/include/clang/Frontend/DiagnosticRenderer.h b/include/clang/Frontend/DiagnosticRenderer.h
index 6ca8d89ec9..f46eb5c500 100644
--- a/include/clang/Frontend/DiagnosticRenderer.h
+++ b/include/clang/Frontend/DiagnosticRenderer.h
@@ -19,6 +19,7 @@
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/LLVM.h"
 #include "clang/Basic/SourceLocation.h"
+#include "llvm/ADT/Optional.h"
 #include "llvm/ADT/PointerUnion.h"
 
 namespace clang {
@@ -92,6 +93,9 @@ protected:
   
   virtual void emitIncludeLocation(SourceLocation Loc, PresumedLoc PLoc,
                                    const SourceManager &SM) = 0;
+  virtual void emitImportLocation(SourceLocation Loc, PresumedLoc PLoc,
+                                  StringRef ModuleName,
+                                  const SourceManager &SM) = 0;
   virtual void emitBuildingModuleLocation(SourceLocation Loc, PresumedLoc PLoc,
                                           StringRef ModuleName,
                                           const SourceManager &SM) = 0;
@@ -103,9 +107,12 @@ protected:
 
   
 private:
-  void emitIncludeStack(SourceLocation Loc, DiagnosticsEngine::Level Level,
-                        const SourceManager &SM);
+  void emitIncludeStack(SourceLocation Loc, PresumedLoc PLoc,
+                        DiagnosticsEngine::Level Level, const SourceManager &SM);
   void emitIncludeStackRecursively(SourceLocation Loc, const SourceManager &SM);
+  void emitImportStack(SourceLocation Loc, const SourceManager &SM);
+  void emitImportStackRecursively(SourceLocation Loc, StringRef ModuleName,
+                                  const SourceManager &SM);
   void emitModuleBuildPath(const SourceManager &SM);
   void emitMacroExpansionsAndCarets(SourceLocation Loc,
                                     DiagnosticsEngine::Level Level,
@@ -154,6 +161,10 @@ public:
                                    PresumedLoc PLoc,
                                    const SourceManager &SM);
 
+  virtual void emitImportLocation(SourceLocation Loc, PresumedLoc PLoc,
+                                  StringRef ModuleName,
+                                  const SourceManager &SM);
+
   virtual void emitBuildingModuleLocation(SourceLocation Loc, PresumedLoc PLoc,
                                           StringRef ModuleName,
                                           const SourceManager &SM);
diff --git a/include/clang/Frontend/TextDiagnostic.h b/include/clang/Frontend/TextDiagnostic.h
index 859bec2cfe..bce4e05efc 100644
--- a/include/clang/Frontend/TextDiagnostic.h
+++ b/include/clang/Frontend/TextDiagnostic.h
@@ -103,6 +103,10 @@ protected:
   virtual void emitIncludeLocation(SourceLocation Loc, PresumedLoc PLoc,
                                    const SourceManager &SM);
 
+  virtual void emitImportLocation(SourceLocation Loc, PresumedLoc PLoc,
+                                  StringRef ModuleName,
+                                  const SourceManager &SM);
+
   virtual void emitBuildingModuleLocation(SourceLocation Loc, PresumedLoc PLoc,
                                           StringRef ModuleName,
                                           const SourceManager &SM);
diff --git a/include/clang/Serialization/ASTReader.h b/include/clang/Serialization/ASTReader.h
index 6b3c4f107f..d51917fcb1 100644
--- a/include/clang/Serialization/ASTReader.h
+++ b/include/clang/Serialization/ASTReader.h
@@ -1546,6 +1546,10 @@ public:
   /// \brief Read the source location entry with index ID.
   virtual bool ReadSLocEntry(int ID);
 
+  /// \brief Retrieve the module import location and module name for the
+  /// given source manager entry ID.
+  virtual std::pair<SourceLocation, StringRef> getModuleImportLoc(int ID);
+
   /// \brief Retrieve the global submodule ID given a module and its local ID
   /// number.
   serialization::SubmoduleID