[Symbolizer] Don't use PE symbol tables to override PDB symbols

[rnk]

Summary

PE files are stripped by default, and only contain the names of exported
symbols.

The actual reason that we bother to do this override by default is
actually due to a quirk of the way -gline-tables-only is implemented, so
I phrased the check as "if we are symbolizing from dwarf, do the symtab
override".

This fixes lots of Windows ASan tests that I broke in r250582.

[samsonov]

LGTM

llvm/trunk/lib/DebugInfo/Symbolize/SymbolizableObjectFile.h

public:
   // Return true if this is a 32-bit x86 PE COFF module.
   bool isWin32Module() const override;
 
   // Returns the preferred base of the module, i.e. where the loader would place
   // it in memory assuming there were no conflicts.
   uint64_t getModulePreferredBase() const override;
 
 private:
+  bool shouldOverrideWithSymbolTable(FunctionNameKind FNKind,
+                                     bool UseSymbolTable) const;
+
   bool getNameFromSymbolTable(object::SymbolRef::Type Type, uint64_t Address,
                               std::string &Name, uint64_t &Addr,
                               uint64_t &Size) const;
   // For big-endian PowerPC64 ELF, OpdAddress is the address of the .opd
   // (function descriptor) section and OpdExtractor refers to its contents.
   std::error_code addSymbol(const object::SymbolRef &Symbol,
                             uint64_t SymbolSize,
                             DataExtractor *OpdExtractor = nullptr,

llvm/trunk/lib/DebugInfo/Symbolize/SymbolizableObjectFile.cpp

 //===-- SymbolizableObjectFile.cpp ----------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // Implementation of SymbolizableObjectFile class.
 //
 //===----------------------------------------------------------------------===//
 
 #include "SymbolizableObjectFile.h"
 #include "llvm/Object/SymbolSize.h"
 #include "llvm/Support/DataExtractor.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
 
 namespace llvm {
 namespace symbolize {
 
 using namespace object;
 
 static DILineInfoSpecifier
 getDILineInfoSpecifier(FunctionNameKind FNKind) {
if (SymbolIterator->first.Size != 0 &&
       SymbolIterator->first.Addr + SymbolIterator->first.Size <= Address)
     return false;
   Name = SymbolIterator->second.str();
   Addr = SymbolIterator->first.Addr;
   Size = SymbolIterator->first.Size;
   return true;
 }
 
+bool SymbolizableObjectFile::shouldOverrideWithSymbolTable(
+    FunctionNameKind FNKind, bool UseSymbolTable) const {
+  // When DWARF is used with -gline-tables-only / -gmlt, the symbol table gives
+  // better answers for linkage names than the DIContext. Otherwise, we are
+  // probably using PEs and PDBs, and we shouldn't do the override. PE files
+  // generally only contain the names of exported symbols.
+  return FNKind == FunctionNameKind::LinkageName && UseSymbolTable &&
+         isa<DWARFContext>(DebugInfoContext.get());
+}
+
 DILineInfo SymbolizableObjectFile::symbolizeCode(uint64_t ModuleOffset,
                                                  FunctionNameKind FNKind,
                                                  bool UseSymbolTable) const {
   DILineInfo LineInfo;
   if (DebugInfoContext) {
     LineInfo = DebugInfoContext->getLineInfoForAddress(
         ModuleOffset, getDILineInfoSpecifier(FNKind));
   }
   // Override function name from symbol table if necessary.
-  if (FNKind == FunctionNameKind::LinkageName && UseSymbolTable) {
+  if (shouldOverrideWithSymbolTable(FNKind, UseSymbolTable)) {
     std::string FunctionName;
     uint64_t Start, Size;
     if (getNameFromSymbolTable(SymbolRef::ST_Function, ModuleOffset,
                                FunctionName, Start, Size)) {
       LineInfo.FunctionName = FunctionName;
     }
   }
   return LineInfo;
 }
 
 DIInliningInfo SymbolizableObjectFile::symbolizeInlinedCode(
     uint64_t ModuleOffset, FunctionNameKind FNKind, bool UseSymbolTable) const {
   DIInliningInfo InlinedContext;
 
   if (DebugInfoContext)
     InlinedContext = DebugInfoContext->getInliningInfoForAddress(
         ModuleOffset, getDILineInfoSpecifier(FNKind));
   // Make sure there is at least one frame in context.
   if (InlinedContext.getNumberOfFrames() == 0)
     InlinedContext.addFrame(DILineInfo());
 
   // Override the function name in lower frame with name from symbol table.
-  if (FNKind == FunctionNameKind::LinkageName && UseSymbolTable) {
+  if (shouldOverrideWithSymbolTable(FNKind, UseSymbolTable)) {
     std::string FunctionName;
     uint64_t Start, Size;
     if (getNameFromSymbolTable(SymbolRef::ST_Function, ModuleOffset,
                                FunctionName, Start, Size)) {
       InlinedContext.getMutableFrame(InlinedContext.getNumberOfFrames() - 1)
           ->FunctionName = FunctionName;
     }
   }