[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.

llvm-svn: 304738

5 files changed, 162 insertions, 4 deletions

diff --git a/llvm/lib/DebugInfo/CodeView/CMakeLists.txt b/llvm/lib/DebugInfo/CodeView/CMakeLists.txt
index 410b89bc949..c543a6e9ae1 100644
--- a/llvm/lib/DebugInfo/CodeView/CMakeLists.txt
+++ b/llvm/lib/DebugInfo/CodeView/CMakeLists.txt
@@ -3,11 +3,9 @@ add_llvm_library(LLVMDebugInfoCodeView
   CodeViewRecordIO.cpp
   CVSymbolVisitor.cpp
   CVTypeVisitor.cpp
-  EnumTables.cpp
-  Formatters.cpp
-  LazyRandomTypeCollection.cpp
-  Line.cpp
   DebugChecksumsSubsection.cpp
+  DebugCrossExSubsection.cpp
+  DebugCrossImpSubsection.cpp
   DebugFrameDataSubsection.cpp
   DebugInlineeLinesSubsection.cpp
   DebugLinesSubsection.cpp
@@ -16,6 +14,10 @@ add_llvm_library(LLVMDebugInfoCodeView
   DebugSubsectionRecord.cpp
   DebugSubsectionVisitor.cpp
   DebugSymbolsSubsection.cpp
+  EnumTables.cpp
+  Formatters.cpp
+  LazyRandomTypeCollection.cpp
+  Line.cpp
   RecordSerialization.cpp
   SymbolRecordMapping.cpp
   SymbolDumper.cpp
diff --git a/llvm/lib/DebugInfo/CodeView/DebugCrossExSubsection.cpp b/llvm/lib/DebugInfo/CodeView/DebugCrossExSubsection.cpp
new file mode 100644
index 00000000000..d8dca5d5c63
--- /dev/null
+++ b/llvm/lib/DebugInfo/CodeView/DebugCrossExSubsection.cpp
@@ -0,0 +1,49 @@
+//===- DebugCrossExSubsection.cpp -------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/CodeView/DebugCrossExSubsection.h"
+
+#include "llvm/DebugInfo/CodeView/CodeViewError.h"
+
+using namespace llvm;
+using namespace llvm::codeview;
+
+Error DebugCrossModuleExportsSubsectionRef::initialize(
+    BinaryStreamReader Reader) {
+  if (Reader.bytesRemaining() % sizeof(CrossModuleExport) != 0)
+    return make_error<CodeViewError>(
+        cv_error_code::corrupt_record,
+        "Cross Scope Exports section is an invalid size!");
+
+  uint32_t Size = Reader.bytesRemaining() / sizeof(CrossModuleExport);
+  return Reader.readArray(References, Size);
+}
+
+Error DebugCrossModuleExportsSubsectionRef::initialize(BinaryStreamRef Stream) {
+  BinaryStreamReader Reader(Stream);
+  return initialize(Reader);
+}
+
+void DebugCrossModuleExportsSubsection::addMapping(uint32_t Local,
+                                                   uint32_t Global) {
+  Mappings[Local] = Global;
+}
+
+uint32_t DebugCrossModuleExportsSubsection::calculateSerializedSize() const {
+  return Mappings.size() * sizeof(CrossModuleExport);
+}
+
+Error DebugCrossModuleExportsSubsection::commit(
+    BinaryStreamWriter &Writer) const {
+  for (const auto &M : Mappings) {
+    if (auto EC = Writer.writeObject(M))
+      return EC;
+  }
+  return Error::success();
+}
diff --git a/llvm/lib/DebugInfo/CodeView/DebugCrossImpSubsection.cpp b/llvm/lib/DebugInfo/CodeView/DebugCrossImpSubsection.cpp
new file mode 100644
index 00000000000..e0ceefcd5fa
--- /dev/null
+++ b/llvm/lib/DebugInfo/CodeView/DebugCrossImpSubsection.cpp
@@ -0,0 +1,91 @@
+//===- DebugCrossImpSubsection.cpp ------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/DebugInfo/CodeView/DebugCrossImpSubsection.h"
+
+#include "llvm/DebugInfo/CodeView/CodeViewError.h"
+#include "llvm/DebugInfo/CodeView/DebugStringTableSubsection.h"
+
+using namespace llvm;
+using namespace llvm::codeview;
+
+namespace llvm {
+Error VarStreamArrayExtractor<CrossModuleImportItem>::extract(
+    BinaryStreamRef Stream, uint32_t &Len,
+    codeview::CrossModuleImportItem &Item) {
+  BinaryStreamReader Reader(Stream);
+  if (Reader.bytesRemaining() < sizeof(CrossModuleImport))
+    return make_error<CodeViewError>(
+        cv_error_code::insufficient_buffer,
+        "Not enough bytes for a Cross Module Import Header!");
+  if (auto EC = Reader.readObject(Item.Header))
+    return EC;
+  if (Reader.bytesRemaining() < Item.Header->Count * sizeof(uint32_t))
+    return make_error<CodeViewError>(
+        cv_error_code::insufficient_buffer,
+        "Not enough to read specified number of Cross Module References!");
+  if (auto EC = Reader.readArray(Item.Imports, Item.Header->Count))
+    return EC;
+  return Error::success();
+}
+}
+
+Error DebugCrossModuleImportsSubsectionRef::initialize(
+    BinaryStreamReader Reader) {
+  return Reader.readArray(References, Reader.bytesRemaining());
+}
+
+Error DebugCrossModuleImportsSubsectionRef::initialize(BinaryStreamRef Stream) {
+  BinaryStreamReader Reader(Stream);
+  return initialize(Reader);
+}
+
+void DebugCrossModuleImportsSubsection::addImport(StringRef Module,
+                                                  uint32_t ImportId) {
+  Strings.insert(Module);
+  std::vector<support::ulittle32_t> Targets = {support::ulittle32_t(ImportId)};
+  auto Result = Mappings.insert(std::make_pair(Module, Targets));
+  if (!Result.second)
+    Result.first->getValue().push_back(Targets[0]);
+}
+
+uint32_t DebugCrossModuleImportsSubsection::calculateSerializedSize() const {
+  uint32_t Size = 0;
+  for (const auto &Item : Mappings) {
+    Size += sizeof(CrossModuleImport);
+    Size += sizeof(support::ulittle32_t) * Item.second.size();
+  }
+  return Size;
+}
+
+Error DebugCrossModuleImportsSubsection::commit(
+    BinaryStreamWriter &Writer) const {
+  using T = decltype(&*Mappings.begin());
+  std::vector<T> Ids;
+  Ids.reserve(Mappings.size());
+
+  for (const auto &M : Mappings)
+    Ids.push_back(&M);
+
+  std::sort(Ids.begin(), Ids.end(), [this](const T &L1, const T &L2) {
+    return Strings.getStringId(L1->getKey()) <
+           Strings.getStringId(L2->getKey());
+  });
+
+  for (const auto &Item : Ids) {
+    CrossModuleImport Imp;
+    Imp.ModuleNameOffset = Strings.getStringId(Item->getKey());
+    Imp.Count = Item->getValue().size();
+    if (auto EC = Writer.writeObject(Imp))
+      return EC;
+    if (auto EC = Writer.writeArray(makeArrayRef(Item->getValue())))
+      return EC;
+  }
+  return Error::success();
+}
diff --git a/llvm/lib/DebugInfo/CodeView/DebugSubsectionRecord.cpp b/llvm/lib/DebugInfo/CodeView/DebugSubsectionRecord.cpp
index cfd1c5d3ab0..0cf31846f25 100644
--- a/llvm/lib/DebugInfo/CodeView/DebugSubsectionRecord.cpp
+++ b/llvm/lib/DebugInfo/CodeView/DebugSubsectionRecord.cpp
@@ -38,6 +38,8 @@ Error DebugSubsectionRecord::initialize(BinaryStreamRef Stream,
   case DebugSubsectionKind::FileChecksums:
   case DebugSubsectionKind::Lines:
   case DebugSubsectionKind::InlineeLines:
+  case DebugSubsectionKind::CrossScopeExports:
+  case DebugSubsectionKind::CrossScopeImports:
     break;
   default:
     llvm_unreachable("Unexpected debug fragment kind!");
diff --git a/llvm/lib/DebugInfo/CodeView/DebugSubsectionVisitor.cpp b/llvm/lib/DebugInfo/CodeView/DebugSubsectionVisitor.cpp
index f2c4dea8685..93fe4e1914b 100644
--- a/llvm/lib/DebugInfo/CodeView/DebugSubsectionVisitor.cpp
+++ b/llvm/lib/DebugInfo/CodeView/DebugSubsectionVisitor.cpp
@@ -10,6 +10,8 @@
 #include "llvm/DebugInfo/CodeView/DebugSubsectionVisitor.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/DebugSubsectionRecord.h"
@@ -44,6 +46,18 @@ Error llvm::codeview::visitDebugSubsection(const DebugSubsectionRecord &R,
       return EC;
     return V.visitInlineeLines(Fragment);
   }
+  case DebugSubsectionKind::CrossScopeExports: {
+    DebugCrossModuleExportsSubsectionRef Section;
+    if (auto EC = Section.initialize(Reader))
+      return EC;
+    return V.visitCrossModuleExports(Section);
+  }
+  case DebugSubsectionKind::CrossScopeImports: {
+    DebugCrossModuleImportsSubsectionRef Section;
+    if (auto EC = Section.initialize(Reader))
+      return EC;
+    return V.visitCrossModuleImports(Section);
+  }
   default: {
     DebugUnknownSubsectionRef Fragment(R.kind(), R.getRecordData());
     return V.visitUnknown(Fragment);