[lldb][TypeSystemClang] Create FileIDs/SourceLocations from DWARF

Author: Michael137

lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.cpp

@@ -9945,3 +9945,33 @@ void TypeSystemClang::LogCreation() const {
     LLDB_LOG(log, "Created new TypeSystem for (ASTContext*){0:x} '{1}'",
              &getASTContext(), getDisplayName());
 }
+
+clang::SourceLocation TypeSystemClang::GetLocForDecl(const Declaration &decl) {
+  // If the Declaration is invalid there is nothing to do.
+  if (!decl.IsValid())
+    return {};
+
+  clang::SourceManager &sm = getASTContext().getSourceManager();
+  clang::FileManager &fm = sm.getFileManager();
+
+  auto fe = fm.getFileRef(decl.GetFile().GetPath());
+  if (!fe)
+    return {};
+
+  clang::FileID fid = sm.translateFile(*fe);
+  if (fid.isInvalid()) {
+    // We see the file for the first time, so create a dummy file for it now.
+
+    // Connect the new dummy file to the main file via some fake include
+    // location. This is necessary as all file's in the SourceManager need to be
+    // reachable via an include chain from the main file.
+    SourceLocation ToIncludeLocOrFakeLoc;
+    assert(sm.getMainFileID().isValid());
+    ToIncludeLocOrFakeLoc = sm.getLocForStartOfFile(sm.getMainFileID());
+    fid = sm.createFileID(*fe, ToIncludeLocOrFakeLoc, clang::SrcMgr::C_User);
+  }
+
+  // Clang requires column numbers to be >= 1..
+  return sm.translateLineCol(fid, decl.GetLine(),
+                             std::max<uint16_t>(decl.GetColumn(), 1));
+}

lldb/source/Plugins/TypeSystem/Clang/TypeSystemClang.h

@@ -1196,11 +1196,7 @@ class TypeSystemClang : public TypeSystem {
   ///
   /// If no \c FileID could be found/created, returns an empty \c
   /// SourceLocation.
-  ///
-  /// FIXME: currently a no-op.
-  clang::SourceLocation GetLocForDecl(const lldb_private::Declaration &decl) {
-    return {};
-  }
+  clang::SourceLocation GetLocForDecl(const lldb_private::Declaration &decl);
 
   // Classes that inherit from TypeSystemClang can see and modify these
   std::string m_target_triple;