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>

llvm-svn: 169042

1 files changed, 19 insertions, 0 deletions

diff --git a/clang/lib/Serialization/ASTReader.cpp b/clang/lib/Serialization/ASTReader.cpp
index c1428d5c68b..908d8c573c0 100644
--- a/clang/lib/Serialization/ASTReader.cpp
+++ b/clang/lib/Serialization/ASTReader.cpp
@@ -1000,6 +1000,25 @@ bool ASTReader::ReadSLocEntry(int ID) {
   return false;
 }
 
+std::pair<SourceLocation, StringRef> ASTReader::getModuleImportLoc(int ID) {
+  if (ID == 0)
+    return std::make_pair(SourceLocation(), "");
+
+  if (unsigned(-ID) - 2 >= getTotalNumSLocs() || ID > 0) {
+    Error("source location entry ID out-of-range for AST file");
+    return std::make_pair(SourceLocation(), "");
+  }
+
+  // Find which module file this entry lands in.
+  ModuleFile *M = GlobalSLocEntryMap.find(-ID)->second;
+  if (M->Kind != MK_Module)
+    return std::make_pair(SourceLocation(), "");
+
+  // FIXME: Can we map this down to a particular submodule? That would be
+  // ideal.
+  return std::make_pair(M->ImportLoc, llvm::sys::path::stem(M->FileName));
+}
+
 /// \brief Find the location where the module F is imported.
 SourceLocation ASTReader::getImportLocation(ModuleFile *F) {
   if (F->ImportLoc.isValid())