[CodeView] Handle Cross Module Imports and Exports.

While it's not entirely clear why a compiler or linker might
put this information into an object or PDB file, one has been
spotted in the wild which was causing llvm-pdbdump to crash.

This patch adds support for reading-writing these sections.
Since I don't know how to get one of the native tools to
generate this kind of debug info, the only test here is one
in which we feed YAML into the tool to produce a PDB and
then spit out YAML from the resulting PDB and make sure that
it matches.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@304738 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 159 insertions, 9 deletions

diff --git a/lib/ObjectYAML/CodeViewYAMLDebugSections.cpp b/lib/ObjectYAML/CodeViewYAMLDebugSections.cpp
index 21d29835624e..fc3d0ceaa15b 100644
--- a/lib/ObjectYAML/CodeViewYAMLDebugSections.cpp
+++ b/lib/ObjectYAML/CodeViewYAMLDebugSections.cpp
@@ -18,6 +18,8 @@
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/DebugInfo/CodeView/CodeViewError.h"
 #include "llvm/DebugInfo/CodeView/DebugChecksumsSubsection.h"
+#include "llvm/DebugInfo/CodeView/DebugCrossExSubsection.h"
+#include "llvm/DebugInfo/CodeView/DebugCrossImpSubsection.h"
 #include "llvm/DebugInfo/CodeView/DebugInlineeLinesSubsection.h"
 #include "llvm/DebugInfo/CodeView/DebugLinesSubsection.h"
 #include "llvm/DebugInfo/CodeView/DebugStringTableSubsection.h"
@@ -38,13 +40,19 @@ LLVM_YAML_IS_SEQUENCE_VECTOR(SourceLineBlock)
 LLVM_YAML_IS_SEQUENCE_VECTOR(SourceLineInfo)
 LLVM_YAML_IS_SEQUENCE_VECTOR(InlineeSite)
 LLVM_YAML_IS_SEQUENCE_VECTOR(InlineeInfo)
+LLVM_YAML_IS_SEQUENCE_VECTOR(CrossModuleExport)
+LLVM_YAML_IS_SEQUENCE_VECTOR(YAMLCrossModuleImport)
 LLVM_YAML_IS_SEQUENCE_VECTOR(StringRef)
+LLVM_YAML_IS_FLOW_SEQUENCE_VECTOR(uint32_t)
 
 LLVM_YAML_DECLARE_SCALAR_TRAITS(HexFormattedString, false)
 LLVM_YAML_DECLARE_ENUM_TRAITS(DebugSubsectionKind)
 LLVM_YAML_DECLARE_ENUM_TRAITS(FileChecksumKind)
 LLVM_YAML_DECLARE_BITSET_TRAITS(LineFlags)
 
+LLVM_YAML_DECLARE_MAPPING_TRAITS(CrossModuleExport)
+LLVM_YAML_DECLARE_MAPPING_TRAITS(YAMLCrossModuleImport)
+LLVM_YAML_DECLARE_MAPPING_TRAITS(CrossModuleImportItem)
 LLVM_YAML_DECLARE_MAPPING_TRAITS(SourceLineEntry)
 LLVM_YAML_DECLARE_MAPPING_TRAITS(SourceColumnEntry)
 LLVM_YAML_DECLARE_MAPPING_TRAITS(SourceFileChecksumEntry)
@@ -114,6 +122,35 @@ struct YAMLInlineeLinesSubsection : public YAMLSubsectionBase {
 
   InlineeInfo InlineeLines;
 };
+
+struct YAMLCrossModuleExportsSubsection : public YAMLSubsectionBase {
+  YAMLCrossModuleExportsSubsection()
+      : YAMLSubsectionBase(DebugSubsectionKind::CrossScopeExports) {}
+
+  void map(IO &IO) override;
+  std::unique_ptr<DebugSubsection>
+  toCodeViewSubsection(DebugStringTableSubsection *Strings,
+                       DebugChecksumsSubsection *Checksums) const override;
+  static Expected<std::shared_ptr<YAMLCrossModuleExportsSubsection>>
+  fromCodeViewSubsection(const DebugCrossModuleExportsSubsectionRef &Exports);
+
+  std::vector<CrossModuleExport> Exports;
+};
+
+struct YAMLCrossModuleImportsSubsection : public YAMLSubsectionBase {
+  YAMLCrossModuleImportsSubsection()
+      : YAMLSubsectionBase(DebugSubsectionKind::CrossScopeImports) {}
+
+  void map(IO &IO) override;
+  std::unique_ptr<DebugSubsection>
+  toCodeViewSubsection(DebugStringTableSubsection *Strings,
+                       DebugChecksumsSubsection *Checksums) const override;
+  static Expected<std::shared_ptr<YAMLCrossModuleImportsSubsection>>
+  fromCodeViewSubsection(const DebugStringTableSubsectionRef &Strings,
+                         const DebugCrossModuleImportsSubsectionRef &Imports);
+
+  std::vector<YAMLCrossModuleImport> Imports;
+};
 }
 
 void ScalarBitSetTraits<LineFlags>::bitset(IO &io, LineFlags &Flags) {
@@ -161,6 +198,17 @@ void MappingTraits<SourceLineBlock>::mapping(IO &IO, SourceLineBlock &Obj) {
   IO.mapRequired("Columns", Obj.Columns);
 }
 
+void MappingTraits<CrossModuleExport>::mapping(IO &IO, CrossModuleExport &Obj) {
+  IO.mapRequired("LocalId", Obj.Local);
+  IO.mapRequired("GlobalId", Obj.Global);
+}
+
+void MappingTraits<YAMLCrossModuleImport>::mapping(IO &IO,
+                                                   YAMLCrossModuleImport &Obj) {
+  IO.mapRequired("Module", Obj.ModuleName);
+  IO.mapRequired("Imports", Obj.ImportIds);
+}
+
 void MappingTraits<SourceFileChecksumEntry>::mapping(
     IO &IO, SourceFileChecksumEntry &Obj) {
   IO.mapRequired("FileName", Obj.FileName);
@@ -196,6 +244,16 @@ void YAMLInlineeLinesSubsection::map(IO &IO) {
   IO.mapRequired("Sites", InlineeLines.Sites);
 }
 
+void YAMLCrossModuleExportsSubsection::map(IO &IO) {
+  IO.mapTag("!CrossModuleExports", true);
+  IO.mapOptional("Exports", Exports);
+}
+
+void YAMLCrossModuleImportsSubsection::map(IO &IO) {
+  IO.mapTag("!CrossModuleImports", true);
+  IO.mapOptional("Imports", Imports);
+}
+
 void MappingTraits<YAMLDebugSubsection>::mapping(
     IO &IO, YAMLDebugSubsection &Subsection) {
   if (!IO.outputting()) {
@@ -206,6 +264,12 @@ void MappingTraits<YAMLDebugSubsection>::mapping(
       Subsection.Subsection = std::make_shared<YAMLLinesSubsection>();
     } else if (IO.mapTag("!InlineeLines")) {
       Subsection.Subsection = std::make_shared<YAMLInlineeLinesSubsection>();
+    } else if (IO.mapTag("!CrossModuleExports")) {
+      Subsection.Subsection =
+          std::make_shared<YAMLCrossModuleExportsSubsection>();
+    } else if (IO.mapTag("!CrossModuleImports")) {
+      Subsection.Subsection =
+          std::make_shared<YAMLCrossModuleImportsSubsection>();
     } else {
       llvm_unreachable("Unexpected subsection tag!");
     }
@@ -213,14 +277,15 @@ void MappingTraits<YAMLDebugSubsection>::mapping(
   Subsection.Subsection->map(IO);
 }
 
-static Expected<const YAMLChecksumsSubsection &>
+static std::shared_ptr<YAMLChecksumsSubsection>
 findChecksums(ArrayRef<YAMLDebugSubsection> Subsections) {
   for (const auto &SS : Subsections) {
     if (SS.Subsection->Kind == DebugSubsectionKind::FileChecksums) {
-      return static_cast<const YAMLChecksumsSubsection &>(*SS.Subsection);
+      return std::static_pointer_cast<YAMLChecksumsSubsection>(SS.Subsection);
     }
   }
-  return make_error<CodeViewError>(cv_error_code::no_records);
+
+  return nullptr;
 }
 
 std::unique_ptr<DebugSubsection> YAMLChecksumsSubsection::toCodeViewSubsection(
@@ -285,6 +350,28 @@ YAMLInlineeLinesSubsection::toCodeViewSubsection(
   return llvm::cast<DebugSubsection>(std::move(Result));
 }
 
+std::unique_ptr<DebugSubsection>
+YAMLCrossModuleExportsSubsection::toCodeViewSubsection(
+    DebugStringTableSubsection *Strings,
+    DebugChecksumsSubsection *Checksums) const {
+  auto Result = llvm::make_unique<DebugCrossModuleExportsSubsection>();
+  for (const auto &M : Exports)
+    Result->addMapping(M.Local, M.Global);
+  return llvm::cast<DebugSubsection>(std::move(Result));
+}
+
+std::unique_ptr<DebugSubsection>
+YAMLCrossModuleImportsSubsection::toCodeViewSubsection(
+    DebugStringTableSubsection *Strings,
+    DebugChecksumsSubsection *Checksums) const {
+  auto Result = llvm::make_unique<DebugCrossModuleImportsSubsection>(*Strings);
+  for (const auto &M : Imports) {
+    for (const auto Id : M.ImportIds)
+      Result->addImport(M.ModuleName, Id);
+  }
+  return llvm::cast<DebugSubsection>(std::move(Result));
+}
+
 static Expected<SourceFileChecksumEntry>
 convertOneChecksum(const DebugStringTableSubsectionRef &Strings,
                    const FileChecksumEntry &CS) {
@@ -391,6 +478,31 @@ YAMLInlineeLinesSubsection::fromCodeViewSubsection(
   return Result;
 }
 
+Expected<std::shared_ptr<YAMLCrossModuleExportsSubsection>>
+YAMLCrossModuleExportsSubsection::fromCodeViewSubsection(
+    const DebugCrossModuleExportsSubsectionRef &Exports) {
+  auto Result = std::make_shared<YAMLCrossModuleExportsSubsection>();
+  Result->Exports.assign(Exports.begin(), Exports.end());
+  return Result;
+}
+
+Expected<std::shared_ptr<YAMLCrossModuleImportsSubsection>>
+YAMLCrossModuleImportsSubsection::fromCodeViewSubsection(
+    const DebugStringTableSubsectionRef &Strings,
+    const DebugCrossModuleImportsSubsectionRef &Imports) {
+  auto Result = std::make_shared<YAMLCrossModuleImportsSubsection>();
+  for (const auto &CMI : Imports) {
+    YAMLCrossModuleImport YCMI;
+    auto ExpectedStr = Strings.getString(CMI.Header->ModuleNameOffset);
+    if (!ExpectedStr)
+      return ExpectedStr.takeError();
+    YCMI.ModuleName = *ExpectedStr;
+    YCMI.ImportIds.assign(CMI.Imports.begin(), CMI.Imports.end());
+    Result->Imports.push_back(YCMI);
+  }
+  return Result;
+}
+
 Expected<std::vector<std::unique_ptr<DebugSubsection>>>
 llvm::CodeViewYAML::convertSubsectionList(
     ArrayRef<YAMLDebugSubsection> Subsections,
@@ -400,11 +512,11 @@ llvm::CodeViewYAML::convertSubsectionList(
     return std::move(Result);
 
   auto Checksums = findChecksums(Subsections);
-  if (!Checksums)
-    return Checksums.takeError();
-  auto ChecksumsBase = Checksums->toCodeViewSubsection(&Strings, nullptr);
-  DebugChecksumsSubsection &CS =
-      llvm::cast<DebugChecksumsSubsection>(*ChecksumsBase);
+  std::unique_ptr<DebugSubsection> ChecksumsBase;
+  if (Checksums)
+    ChecksumsBase = Checksums->toCodeViewSubsection(&Strings, nullptr);
+  DebugChecksumsSubsection *CS =
+      static_cast<DebugChecksumsSubsection *>(ChecksumsBase.get());
   for (const auto &SS : Subsections) {
     // We've already converted the checksums subsection, don't do it
     // twice.
@@ -412,7 +524,8 @@ llvm::CodeViewYAML::convertSubsectionList(
     if (SS.Subsection->Kind == DebugSubsectionKind::FileChecksums)
       CVS = std::move(ChecksumsBase);
     else
-      CVS = SS.Subsection->toCodeViewSubsection(&Strings, &CS);
+      CVS = SS.Subsection->toCodeViewSubsection(&Strings, CS);
+    assert(CVS != nullptr);
     Result.push_back(std::move(CVS));
   }
   return std::move(Result);
@@ -429,6 +542,10 @@ struct SubsectionConversionVisitor : public DebugSubsectionVisitor {
   Error visitLines(DebugLinesSubsectionRef &Lines) override;
   Error visitFileChecksums(DebugChecksumsSubsectionRef &Checksums) override;
   Error visitInlineeLines(DebugInlineeLinesSubsectionRef &Inlinees) override;
+  Error visitCrossModuleExports(
+      DebugCrossModuleExportsSubsectionRef &Checksums) override;
+  Error visitCrossModuleImports(
+      DebugCrossModuleImportsSubsectionRef &Inlinees) override;
 
   YAMLDebugSubsection Subsection;
 
@@ -470,6 +587,26 @@ Error SubsectionConversionVisitor::visitInlineeLines(
   Subsection.Subsection = *Result;
   return Error::success();
 }
+
+Error SubsectionConversionVisitor::visitCrossModuleExports(
+    DebugCrossModuleExportsSubsectionRef &Exports) {
+  auto Result =
+      YAMLCrossModuleExportsSubsection::fromCodeViewSubsection(Exports);
+  if (!Result)
+    return Result.takeError();
+  Subsection.Subsection = *Result;
+  return Error::success();
+}
+
+Error SubsectionConversionVisitor::visitCrossModuleImports(
+    DebugCrossModuleImportsSubsectionRef &Imports) {
+  auto Result = YAMLCrossModuleImportsSubsection::fromCodeViewSubsection(
+      Strings, Imports);
+  if (!Result)
+    return Result.takeError();
+  Subsection.Subsection = *Result;
+  return Error::success();
+}
 }
 
 Expected<YAMLDebugSubsection> YAMLDebugSubsection::fromCodeViewSubection(
diff --git a/lib/ObjectYAML/CodeViewYAMLSymbols.cpp b/lib/ObjectYAML/CodeViewYAMLSymbols.cpp
index bd97af3a9323..fa3f1e0b60aa 100644
--- a/lib/ObjectYAML/CodeViewYAMLSymbols.cpp
+++ b/lib/ObjectYAML/CodeViewYAMLSymbols.cpp
@@ -47,6 +47,18 @@ LLVM_YAML_DECLARE_ENUM_TRAITS(RegisterId)
 LLVM_YAML_DECLARE_ENUM_TRAITS(TrampolineType)
 LLVM_YAML_DECLARE_ENUM_TRAITS(ThunkOrdinal)
 
+LLVM_YAML_STRONG_TYPEDEF(llvm::StringRef, TypeName)
+
+LLVM_YAML_DECLARE_SCALAR_TRAITS(TypeName, true)
+
+StringRef ScalarTraits<TypeName>::input(StringRef S, void *V, TypeName &T) {
+  return ScalarTraits<StringRef>::input(S, V, T.value);
+}
+void ScalarTraits<TypeName>::output(const TypeName &T, void *V,
+                                    llvm::raw_ostream &R) {
+  ScalarTraits<StringRef>::output(T.value, V, R);
+}
+
 void ScalarEnumerationTraits<SymbolKind>::enumeration(IO &io,
                                                       SymbolKind &Value) {
   auto SymbolNames = getSymbolTypeNames();
@@ -264,6 +276,7 @@ template <> void SymbolRecordImpl<InlineSiteSym>::map(IO &IO) {
 template <> void SymbolRecordImpl<LocalSym>::map(IO &IO) {
   IO.mapRequired("Type", Symbol.Type);
   IO.mapRequired("Flags", Symbol.Flags);
+
   IO.mapRequired("VarName", Symbol.Name);
 }