[LLD/PDB] Write actual records to the globals stream.

Previously we were writing an empty globals stream.  Windows
tools interpret this as "private symbols are not present in
this PDB", even when they are, so we need to fix this.  Regardless,
without it we don't have information about global variables, so
we need to fix it anyway.  This patch does that.

With this patch, the "lm" command in WinDbg correctly reports
that we have private symbols available, but the "dv" command
still refuses to display local variables.

Differential Revision: https://reviews.llvm.org/D36535

llvm-svn: 310743

4 files changed, 82 insertions, 5 deletions

diff --git a/llvm/lib/DebugInfo/CodeView/CMakeLists.txt b/llvm/lib/DebugInfo/CodeView/CMakeLists.txt
index b94bb0c80c7..b0cefe64fdd 100644
--- a/llvm/lib/DebugInfo/CodeView/CMakeLists.txt
+++ b/llvm/lib/DebugInfo/CodeView/CMakeLists.txt
@@ -19,6 +19,7 @@ add_llvm_library(LLVMDebugInfoCodeView
   Formatters.cpp
   LazyRandomTypeCollection.cpp
   Line.cpp
+  RecordName.cpp
   RecordSerialization.cpp
   StringsAndChecksums.cpp
   SymbolRecordMapping.cpp
@@ -27,7 +28,6 @@ add_llvm_library(LLVMDebugInfoCodeView
   TypeDumpVisitor.cpp
   TypeIndex.cpp
   TypeIndexDiscovery.cpp
-  TypeName.cpp
   TypeRecordMapping.cpp
   TypeSerializer.cpp
   TypeStreamMerger.cpp
diff --git a/llvm/lib/DebugInfo/CodeView/LazyRandomTypeCollection.cpp b/llvm/lib/DebugInfo/CodeView/LazyRandomTypeCollection.cpp
index 5aaf3f1453a..6db921ed939 100644
--- a/llvm/lib/DebugInfo/CodeView/LazyRandomTypeCollection.cpp
+++ b/llvm/lib/DebugInfo/CodeView/LazyRandomTypeCollection.cpp
@@ -13,7 +13,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/DebugInfo/CodeView/CodeViewError.h"
-#include "llvm/DebugInfo/CodeView/TypeName.h"
+#include "llvm/DebugInfo/CodeView/RecordName.h"
 #include "llvm/DebugInfo/CodeView/TypeRecord.h"
 #include "llvm/Support/BinaryStreamReader.h"
 #include "llvm/Support/Endian.h"
diff --git a/llvm/lib/DebugInfo/CodeView/TypeName.cpp b/llvm/lib/DebugInfo/CodeView/RecordName.cpp
index 2eb8b81862f..15fb1724d23 100644
--- a/llvm/lib/DebugInfo/CodeView/TypeName.cpp
+++ b/llvm/lib/DebugInfo/CodeView/RecordName.cpp
@@ -1,4 +1,4 @@
-//===- TypeName.cpp ------------------------------------------- *- C++ --*-===//
+//===- RecordName.cpp ----------------------------------------- *- C++ --*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
@@ -7,10 +7,12 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/DebugInfo/CodeView/TypeName.h"
+#include "llvm/DebugInfo/CodeView/RecordName.h"
 
 #include "llvm/ADT/SmallString.h"
+#include "llvm/DebugInfo/CodeView/CVSymbolVisitor.h"
 #include "llvm/DebugInfo/CodeView/CVTypeVisitor.h"
+#include "llvm/DebugInfo/CodeView/SymbolRecordMapping.h"
 #include "llvm/DebugInfo/CodeView/TypeVisitorCallbacks.h"
 #include "llvm/Support/FormatVariadic.h"
 
@@ -241,3 +243,78 @@ std::string llvm::codeview::computeTypeName(TypeCollection &Types,
   }
   return Computer.name();
 }
+
+static int getSymbolNameOffset(CVSymbol Sym) {
+  switch (Sym.kind()) {
+  // See ProcSym
+  case SymbolKind::S_GPROC32:
+  case SymbolKind::S_LPROC32:
+  case SymbolKind::S_GPROC32_ID:
+  case SymbolKind::S_LPROC32_ID:
+  case SymbolKind::S_LPROC32_DPC:
+  case SymbolKind::S_LPROC32_DPC_ID:
+    return 35;
+  // See Thunk32Sym
+  case SymbolKind::S_THUNK32:
+    return 21;
+  // See SectionSym
+  case SymbolKind::S_SECTION:
+    return 16;
+  // See CoffGroupSym
+  case SymbolKind::S_COFFGROUP:
+    return 14;
+  // See PublicSym32, FileStaticSym, RegRelativeSym, DataSym, ThreadLocalDataSym
+  case SymbolKind::S_PUB32:
+  case SymbolKind::S_FILESTATIC:
+  case SymbolKind::S_REGREL32:
+  case SymbolKind::S_GDATA32:
+  case SymbolKind::S_LDATA32:
+  case SymbolKind::S_LMANDATA:
+  case SymbolKind::S_GMANDATA:
+  case SymbolKind::S_LTHREAD32:
+  case SymbolKind::S_GTHREAD32:
+    return 10;
+  // See RegisterSym and LocalSym
+  case SymbolKind::S_REGISTER:
+  case SymbolKind::S_LOCAL:
+    return 6;
+  // See BlockSym
+  case SymbolKind::S_BLOCK32:
+    return 18;
+  // See LabelSym
+  case SymbolKind::S_LABEL32:
+    return 7;
+  // See ObjNameSym, ExportSym, and UDTSym
+  case SymbolKind::S_OBJNAME:
+  case SymbolKind::S_EXPORT:
+  case SymbolKind::S_UDT:
+    return 4;
+  // See BPRelativeSym
+  case SymbolKind::S_BPREL32:
+    return 8;
+  default:
+    return -1;
+  }
+}
+
+StringRef llvm::codeview::getSymbolName(CVSymbol Sym) {
+  if (Sym.kind() == SymbolKind::S_CONSTANT) {
+    // S_CONSTANT is preceded by an APSInt, which has a variable length.  So we
+    // have to do a full deserialization.
+    BinaryStreamReader Reader(Sym.content(), llvm::support::little);
+    // The container doesn't matter for single records.
+    SymbolRecordMapping Mapping(Reader, CodeViewContainer::ObjectFile);
+    ConstantSym Const(SymbolKind::S_CONSTANT);
+    cantFail(Mapping.visitSymbolBegin(Sym));
+    cantFail(Mapping.visitKnownRecord(Sym, Const));
+    cantFail(Mapping.visitSymbolEnd(Sym));
+    return Const.Name;
+  }
+
+  int Offset = getSymbolNameOffset(Sym);
+  if (Offset == -1)
+    return StringRef();
+
+  StringRef StringData = toStringRef(Sym.content()).drop_front(Offset);
+  return StringData.split('\0').first;
+}
diff --git a/llvm/lib/DebugInfo/CodeView/TypeTableCollection.cpp b/llvm/lib/DebugInfo/CodeView/TypeTableCollection.cpp
index 4eca5aeaa0a..456d6f19b23 100644
--- a/llvm/lib/DebugInfo/CodeView/TypeTableCollection.cpp
+++ b/llvm/lib/DebugInfo/CodeView/TypeTableCollection.cpp
@@ -10,7 +10,7 @@
 #include "llvm/DebugInfo/CodeView/TypeTableCollection.h"
 
 #include "llvm/DebugInfo/CodeView/CVTypeVisitor.h"
-#include "llvm/DebugInfo/CodeView/TypeName.h"
+#include "llvm/DebugInfo/CodeView/RecordName.h"
 #include "llvm/DebugInfo/CodeView/TypeTableBuilder.h"
 #include "llvm/Support/BinaryByteStream.h"
 #include "llvm/Support/BinaryStreamReader.h"