diff --git a/clang-tools-extra/clang-query/Query.cpp b/clang-tools-extra/clang-query/Query.cpp
index 8eafc5eed7507e..2fc7af6a56e14d 100644
--- a/clang-tools-extra/clang-query/Query.cpp
+++ b/clang-tools-extra/clang-query/Query.cpp
@@ -43,6 +43,15 @@ bool HelpQuery::run(llvm::raw_ostream &OS, QuerySession &QS) const {
         "Set whether to bind the root matcher to \"root\".\n"
         "  set print-matcher (true|false)    "
         "Set whether to print the current matcher,\n"
+        "  set traversal <kind>              "
+        "Set traversal kind of clang-query session. Available kinds are:\n"
+        "    AsIs                            "
+        "Print and match the AST as clang sees it.\n"
+        "    IgnoreImplicitCastsAndParentheses  "
+        "Omit implicit casts and parens in matching and dumping.\n"
+        "    IgnoreUnlessSpelledInSource     "
+        "Omit AST nodes unless spelled in the source.  This mode is the "
+        "default.\n"
         "  set output <feature>              "
         "Set whether to output only <feature> content.\n"
         "  enable output <feature>           "
@@ -98,6 +107,8 @@ bool MatchQuery::run(llvm::raw_ostream &OS, QuerySession &QS) const {
       OS << "Not a valid top-level matcher.\n";
       return false;
     }
+
+    AST->getASTContext().getParentMapContext().setTraversalKind(QS.TK);
     Finder.matchAST(AST->getASTContext());
 
     if (QS.PrintMatcher) {
@@ -148,6 +159,7 @@ bool MatchQuery::run(llvm::raw_ostream &OS, QuerySession &QS) const {
           const SourceManager &SM = Ctx.getSourceManager();
           ASTDumper Dumper(OS, &Ctx.getCommentCommandTraits(), &SM,
                 SM.getDiagnostics().getShowColors(), Ctx.getPrintingPolicy());
+          Dumper.SetTraversalKind(QS.TK);
           Dumper.Visit(BI->second);
           OS << "\n";
         }
diff --git a/clang-tools-extra/clang-query/Query.h b/clang-tools-extra/clang-query/Query.h
index 78bcbc79cdf872..223644fe2e515b 100644
--- a/clang-tools-extra/clang-query/Query.h
+++ b/clang-tools-extra/clang-query/Query.h
@@ -28,6 +28,7 @@ enum QueryKind {
   QK_Match,
   QK_SetBool,
   QK_SetOutputKind,
+  QK_SetTraversalKind,
   QK_EnableOutputKind,
   QK_DisableOutputKind,
   QK_Quit
@@ -119,6 +120,10 @@ template <> struct SetQueryKind<OutputKind> {
   static const QueryKind value = QK_SetOutputKind;
 };
 
+template <> struct SetQueryKind<ast_type_traits::TraversalKind> {
+  static const QueryKind value = QK_SetTraversalKind;
+};
+
 /// Query for "set VAR VALUE".
 template <typename T> struct SetQuery : Query {
   SetQuery(T QuerySession::*Var, T Value)
diff --git a/clang-tools-extra/clang-query/QueryParser.cpp b/clang-tools-extra/clang-query/QueryParser.cpp
index ecc189a7db2f5d..2f1965e77ab4b4 100644
--- a/clang-tools-extra/clang-query/QueryParser.cpp
+++ b/clang-tools-extra/clang-query/QueryParser.cpp
@@ -128,6 +128,24 @@ template <typename QueryType> QueryRef QueryParser::parseSetOutputKind() {
   llvm_unreachable("Invalid output kind");
 }
 
+QueryRef QueryParser::parseSetTraversalKind(
+    ast_type_traits::TraversalKind QuerySession::*Var) {
+  StringRef ValStr;
+  unsigned Value =
+      LexOrCompleteWord<unsigned>(this, ValStr)
+          .Case("AsIs", ast_type_traits::TK_AsIs)
+          .Case("IgnoreImplicitCastsAndParentheses",
+                ast_type_traits::TK_IgnoreImplicitCastsAndParentheses)
+          .Case("IgnoreUnlessSpelledInSource",
+                ast_type_traits::TK_IgnoreUnlessSpelledInSource)
+          .Default(~0u);
+  if (Value == ~0u) {
+    return new InvalidQuery("expected traversal kind, got '" + ValStr + "'");
+  }
+  return new SetQuery<ast_type_traits::TraversalKind>(
+      Var, static_cast<ast_type_traits::TraversalKind>(Value));
+}
+
 QueryRef QueryParser::endQuery(QueryRef Q) {
   StringRef Extra = Line;
   StringRef ExtraTrimmed = Extra.drop_while(
@@ -171,7 +189,8 @@ enum ParsedQueryVariable {
   PQV_Invalid,
   PQV_Output,
   PQV_BindRoot,
-  PQV_PrintMatcher
+  PQV_PrintMatcher,
+  PQV_Traversal
 };
 
 QueryRef makeInvalidQueryFromDiagnostics(const Diagnostics &Diag) {
@@ -272,6 +291,7 @@ QueryRef QueryParser::doParse() {
             .Case("output", PQV_Output)
             .Case("bind-root", PQV_BindRoot)
             .Case("print-matcher", PQV_PrintMatcher)
+            .Case("traversal", PQV_Traversal)
             .Default(PQV_Invalid);
     if (VarStr.empty())
       return new InvalidQuery("expected variable name");
@@ -289,6 +309,9 @@ QueryRef QueryParser::doParse() {
     case PQV_PrintMatcher:
       Q = parseSetBool(&QuerySession::PrintMatcher);
       break;
+    case PQV_Traversal:
+      Q = parseSetTraversalKind(&QuerySession::TK);
+      break;
     case PQV_Invalid:
       llvm_unreachable("Invalid query kind");
     }
diff --git a/clang-tools-extra/clang-query/QueryParser.h b/clang-tools-extra/clang-query/QueryParser.h
index 12664777ee447f..68f420dc0994ef 100644
--- a/clang-tools-extra/clang-query/QueryParser.h
+++ b/clang-tools-extra/clang-query/QueryParser.h
@@ -43,6 +43,8 @@ class QueryParser {
   template <typename T> struct LexOrCompleteWord;
 
   QueryRef parseSetBool(bool QuerySession::*Var);
+  QueryRef
+  parseSetTraversalKind(ast_type_traits::TraversalKind QuerySession::*Var);
   template <typename QueryType> QueryRef parseSetOutputKind();
   QueryRef completeMatcherExpression();
 
diff --git a/clang-tools-extra/clang-query/QuerySession.h b/clang-tools-extra/clang-query/QuerySession.h
index 0f3bc1aa64641a..1660e4039f613b 100644
--- a/clang-tools-extra/clang-query/QuerySession.h
+++ b/clang-tools-extra/clang-query/QuerySession.h
@@ -9,6 +9,7 @@
 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_QUERY_QUERY_SESSION_H
 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_QUERY_QUERY_SESSION_H
 
+#include "clang/AST/ASTTypeTraits.h"
 #include "clang/ASTMatchers/Dynamic/VariantValue.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/StringMap.h"
@@ -25,7 +26,7 @@ class QuerySession {
   QuerySession(llvm::ArrayRef<std::unique_ptr<ASTUnit>> ASTs)
       : ASTs(ASTs), PrintOutput(false), DiagOutput(true),
         DetailedASTOutput(false), BindRoot(true), PrintMatcher(false),
-        Terminate(false) {}
+        Terminate(false), TK(ast_type_traits::TK_IgnoreUnlessSpelledInSource) {}
 
   llvm::ArrayRef<std::unique_ptr<ASTUnit>> ASTs;
 
@@ -36,6 +37,8 @@ class QuerySession {
   bool BindRoot;
   bool PrintMatcher;
   bool Terminate;
+
+  ast_type_traits::TraversalKind TK;
   llvm::StringMap<ast_matchers::dynamic::VariantValue> NamedValues;
 };
 
diff --git a/clang-tools-extra/unittests/clang-query/QueryParserTest.cpp b/clang-tools-extra/unittests/clang-query/QueryParserTest.cpp
index 4ebe1237b21cf2..4a0a80146af4be 100644
--- a/clang-tools-extra/unittests/clang-query/QueryParserTest.cpp
+++ b/clang-tools-extra/unittests/clang-query/QueryParserTest.cpp
@@ -110,6 +110,18 @@ TEST_F(QueryParserTest, Set) {
   ASSERT_TRUE(isa<SetQuery<bool> >(Q));
   EXPECT_EQ(&QuerySession::BindRoot, cast<SetQuery<bool> >(Q)->Var);
   EXPECT_EQ(true, cast<SetQuery<bool> >(Q)->Value);
+
+  Q = parse("set traversal AsIs");
+  ASSERT_TRUE(isa<SetQuery<ast_type_traits::TraversalKind>>(Q));
+  EXPECT_EQ(&QuerySession::TK,
+            cast<SetQuery<ast_type_traits::TraversalKind>>(Q)->Var);
+  EXPECT_EQ(ast_type_traits::TK_AsIs,
+            cast<SetQuery<ast_type_traits::TraversalKind>>(Q)->Value);
+
+  Q = parse("set traversal NotATraversal");
+  ASSERT_TRUE(isa<InvalidQuery>(Q));
+  EXPECT_EQ("expected traversal kind, got 'NotATraversal'",
+            cast<InvalidQuery>(Q)->ErrStr);
 }
 
 TEST_F(QueryParserTest, Match) {
@@ -197,6 +209,11 @@ TEST_F(QueryParserTest, Complete) {
   EXPECT_EQ("utput ", Comps[0].TypedText);
   EXPECT_EQ("output", Comps[0].DisplayText);
 
+  Comps = QueryParser::complete("set t", 5, QS);
+  ASSERT_EQ(1u, Comps.size());
+  EXPECT_EQ("raversal ", Comps[0].TypedText);
+  EXPECT_EQ("traversal", Comps[0].DisplayText);
+
   Comps = QueryParser::complete("enable ", 7, QS);
   ASSERT_EQ(1u, Comps.size());
   EXPECT_EQ("output ", Comps[0].TypedText);
@@ -214,6 +231,16 @@ TEST_F(QueryParserTest, Complete) {
   EXPECT_EQ("dump ", Comps[3].TypedText);
   EXPECT_EQ("dump", Comps[3].DisplayText);
 
+  Comps = QueryParser::complete("set traversal ", 14, QS);
+  ASSERT_EQ(3u, Comps.size());
+
+  EXPECT_EQ("AsIs ", Comps[0].TypedText);
+  EXPECT_EQ("AsIs", Comps[0].DisplayText);
+  EXPECT_EQ("IgnoreImplicitCastsAndParentheses ", Comps[1].TypedText);
+  EXPECT_EQ("IgnoreImplicitCastsAndParentheses", Comps[1].DisplayText);
+  EXPECT_EQ("IgnoreUnlessSpelledInSource ", Comps[2].TypedText);
+  EXPECT_EQ("IgnoreUnlessSpelledInSource", Comps[2].DisplayText);
+
   Comps = QueryParser::complete("match while", 11, QS);
   ASSERT_EQ(1u, Comps.size());
   EXPECT_EQ("Stmt(", Comps[0].TypedText);
diff --git a/llvm/lib/ObjectYAML/ELFEmitter.cpp b/llvm/lib/ObjectYAML/ELFEmitter.cpp
index 2a3839509fafc6..95d74eeeb6e6ea 100644
--- a/llvm/lib/ObjectYAML/ELFEmitter.cpp
+++ b/llvm/lib/ObjectYAML/ELFEmitter.cpp
@@ -218,6 +218,7 @@ template <class ELFT> class ELFState {
 
   void assignSectionAddress(Elf_Shdr &SHeader, ELFYAML::Section *YAMLSec);
 
+  BumpPtrAllocator StringAlloc;
   uint64_t alignToOffset(ContiguousBlobAccumulator &CBA, uint64_t Align,
                          llvm::Optional<llvm::yaml::Hex64> Offset);
 
@@ -241,11 +242,6 @@ template <class ELFT>
 ELFState<ELFT>::ELFState(ELFYAML::Object &D, yaml::ErrorHandler EH)
     : Doc(D), ErrHandler(EH) {
   std::vector<ELFYAML::Section *> Sections = Doc.getSections();
-  StringSet<> DocSections;
-  for (const ELFYAML::Section *Sec : Sections)
-    if (!Sec->Name.empty())
-      DocSections.insert(Sec->Name);
-
   // Insert SHT_NULL section implicitly when it is not defined in YAML.
   if (Sections.empty() || Sections.front()->Type != ELF::SHT_NULL)
     Doc.Chunks.insert(
@@ -253,6 +249,24 @@ ELFState<ELFT>::ELFState(ELFYAML::Object &D, yaml::ErrorHandler EH)
         std::make_unique<ELFYAML::Section>(
             ELFYAML::Chunk::ChunkKind::RawContent, /*IsImplicit=*/true));
 
+  // We add a technical suffix for each unnamed section/fill. It does not affect
+  // the output, but allows us to map them by name in the code and report better
+  // error messages.
+  StringSet<> DocSections;
+  for (size_t I = 0; I < Doc.Chunks.size(); ++I) {
+    const std::unique_ptr<ELFYAML::Chunk> &C = Doc.Chunks[I];
+    if (C->Name.empty()) {
+      std::string NewName = ELFYAML::appendUniqueSuffix(
+          /*Name=*/"", "index " + Twine(I));
+      C->Name = StringRef(NewName).copy(StringAlloc);
+      assert(ELFYAML::dropUniqueSuffix(C->Name).empty());
+    }
+
+    if (!DocSections.insert(C->Name).second)
+      reportError("repeated section/fill name: '" + C->Name +
+                  "' at YAML section/fill number " + Twine(I));
+  }
+
   std::vector<StringRef> ImplicitSections;
   if (Doc.DynamicSymbols)
     ImplicitSections.insert(ImplicitSections.end(), {".dynsym", ".dynstr"});
@@ -401,22 +415,28 @@ bool ELFState<ELFT>::initImplicitHeader(ContiguousBlobAccumulator &CBA,
   return true;
 }
 
-constexpr StringRef SuffixStart = " (";
+constexpr char SuffixStart = '(';
 constexpr char SuffixEnd = ')';
 
 std::string llvm::ELFYAML::appendUniqueSuffix(StringRef Name,
                                               const Twine &Msg) {
-  return (Name + SuffixStart + Msg + Twine(SuffixEnd)).str();
+  // Do not add a space when a Name is empty.
+  std::string Ret = Name.empty() ? "" : Name.str() + ' ';
+  return Ret + (Twine(SuffixStart) + Msg + Twine(SuffixEnd)).str();
 }
 
 StringRef llvm::ELFYAML::dropUniqueSuffix(StringRef S) {
   if (S.empty() || S.back() != SuffixEnd)
     return S;
 
+  // A special case for empty names. See appendUniqueSuffix() above.
   size_t SuffixPos = S.rfind(SuffixStart);
-  if (SuffixPos == StringRef::npos)
+  if (SuffixPos == 0)
+    return "";
+
+  if (SuffixPos == StringRef::npos || S[SuffixPos - 1] != ' ')
     return S;
-  return S.substr(0, SuffixPos);
+  return S.substr(0, SuffixPos - 1);
 }
 
 template <class ELFT>
@@ -426,7 +446,6 @@ void ELFState<ELFT>::initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
   // valid SHN_UNDEF entry since SHT_NULL == 0.
   SHeaders.resize(Doc.getSections().size());
 
-  size_t SecNdx = -1;
   for (const std::unique_ptr<ELFYAML::Chunk> &D : Doc.Chunks) {
     if (ELFYAML::Fill *S = dyn_cast<ELFYAML::Fill>(D.get())) {
       S->Offset = alignToOffset(CBA, /*Align=*/1, S->Offset);
@@ -435,16 +454,16 @@ void ELFState<ELFT>::initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
       continue;
     }
 
-    ++SecNdx;
     ELFYAML::Section *Sec = cast<ELFYAML::Section>(D.get());
-    if (SecNdx == 0 && Sec->IsImplicit)
+    bool IsFirstUndefSection = D == Doc.Chunks.front();
+    if (IsFirstUndefSection && Sec->IsImplicit)
       continue;
 
     // We have a few sections like string or symbol tables that are usually
     // added implicitly to the end. However, if they are explicitly specified
     // in the YAML, we need to write them here. This ensures the file offset
     // remains correct.
-    Elf_Shdr &SHeader = SHeaders[SecNdx];
+    Elf_Shdr &SHeader = SHeaders[SN2I.get(Sec->Name)];
     if (initImplicitHeader(CBA, SHeader, Sec->Name,
                            Sec->IsImplicit ? nullptr : Sec))
       continue;
@@ -461,7 +480,6 @@ void ELFState<ELFT>::initSectionHeaders(std::vector<Elf_Shdr> &SHeaders,
 
     // Set the offset for all sections, except the SHN_UNDEF section with index
     // 0 when not explicitly requested.
-    bool IsFirstUndefSection = SecNdx == 0;
     if (!IsFirstUndefSection || Sec->Offset)
       SHeader.sh_offset = alignToOffset(CBA, SHeader.sh_addralign, Sec->Offset);
 
@@ -1420,21 +1438,10 @@ void ELFState<ELFT>::writeFill(ELFYAML::Fill &Fill,
 
 template <class ELFT> void ELFState<ELFT>::buildSectionIndex() {
   size_t SecNdx = -1;
-  StringSet<> Seen;
-  for (size_t I = 0; I < Doc.Chunks.size(); ++I) {
-    const std::unique_ptr<ELFYAML::Chunk> &C = Doc.Chunks[I];
-    bool IsSection = isa<ELFYAML::Section>(C.get());
-    if (IsSection)
-      ++SecNdx;
-
-    if (C->Name.empty())
-      continue;
-
-    if (!Seen.insert(C->Name).second)
-      reportError("repeated section/fill name: '" + C->Name +
-                  "' at YAML section/fill number " + Twine(I));
-    if (!IsSection || HasError)
+  for (const std::unique_ptr<ELFYAML::Chunk> &C : Doc.Chunks) {
+    if (!isa<ELFYAML::Section>(C.get()))
       continue;
+    ++SecNdx;
 
     if (!SN2I.addName(C->Name, SecNdx))
       llvm_unreachable("buildSectionIndex() failed");
@@ -1497,6 +1504,8 @@ template <class ELFT>
 bool ELFState<ELFT>::writeELF(raw_ostream &OS, ELFYAML::Object &Doc,
                               yaml::ErrorHandler EH) {
   ELFState<ELFT> State(Doc, EH);
+  if (State.HasError)
+    return false;
 
   // Finalize .strtab and .dynstr sections. We do that early because want to
   // finalize the string table builders before writing the content of the
@@ -1504,9 +1513,6 @@ bool ELFState<ELFT>::writeELF(raw_ostream &OS, ELFYAML::Object &Doc,
   State.finalizeStrings();
 
   State.buildSectionIndex();
-  if (State.HasError)
-    return false;
-
   State.buildSymbolIndexes();
 
   std::vector<Elf_Phdr> PHeaders;
diff --git a/llvm/test/tools/yaml2obj/ELF/custom-null-section.yaml b/llvm/test/tools/yaml2obj/ELF/custom-null-section.yaml
index 20ea73ec834ee2..0ccff19eaf8578 100644
--- a/llvm/test/tools/yaml2obj/ELF/custom-null-section.yaml
+++ b/llvm/test/tools/yaml2obj/ELF/custom-null-section.yaml
@@ -128,7 +128,8 @@ Sections:
 
 # RUN: not yaml2obj --docnum=6 %s -o %t6 2>&1 | FileCheck %s --check-prefix=CASE4
 
-# CASE4: error: unknown section referenced: '.foo' by YAML section ''
+# CASE4:      error: unknown section referenced: '.foo' by YAML section '(index 0)'
+# CASE4-NEXT: error: unknown section referenced: '.bar' by YAML section '(index 1)'
 
 --- !ELF
 FileHeader:
@@ -139,6 +140,8 @@ FileHeader:
 Sections:
   - Type: SHT_NULL
     Link: .foo
+  - Type: SHT_NULL
+    Link: .bar
 
 ## Check that null section fields are set to zero, if they are unspecified.
 
diff --git a/llvm/test/tools/yaml2obj/ELF/section-link.yaml b/llvm/test/tools/yaml2obj/ELF/section-link.yaml
index efe4d3fea74d57..bd82058a92ac56 100644
--- a/llvm/test/tools/yaml2obj/ELF/section-link.yaml
+++ b/llvm/test/tools/yaml2obj/ELF/section-link.yaml
@@ -28,8 +28,10 @@ Sections:
 
 # RUN: not yaml2obj --docnum=2 %s 2>&1 | FileCheck %s --check-prefix=ERR
 
-# ERR: error: unknown section referenced: '.unknown1' by YAML section '.foo'
-# ERR: error: unknown section referenced: '.unknown2' by YAML section '.bar'
+# ERR:      error: unknown section referenced: '.unknown1' by YAML section '.foo'
+# ERR-NEXT: error: unknown section referenced: '.unknown2' by YAML section '(index 2)'
+# ERR-NEXT: error: unknown section referenced: '.unknown3' by YAML section '.bar'
+# ERR-NEXT: error: unknown section referenced: '.unknown4' by YAML section '(index 4)'
 
 --- !ELF
 FileHeader:
@@ -41,9 +43,13 @@ Sections:
   - Name: .foo
     Type: SHT_PROGBITS
     Link: .unknown1
+  - Type: SHT_PROGBITS
+    Link: .unknown2
   - Name: .bar
     Type: SHT_PROGBITS
-    Link: .unknown2
+    Link: .unknown3
+  - Type: SHT_PROGBITS
+    Link: .unknown4
 
 ## Check we link SHT_GROUP to a symbol table by default if it exists.
 ## Also, check we can set an arbitrary value for sh_link.