[llvm-readobj] Fix/improve printing WinEH unwind info for linked PE images

[mstorsjo]

Summary

ARMWinEHPrinter was already designed to handle linked PE images (since d2941b43f40d), but resolving symbols didn't consistently take the image base into account (as linked images seldom have a symbol table, except for in MinGW setups).

Win64EHDumper wasn't really designed to handle linked images (it would crash if executed on such a file), but a few concepts (getSymbol, taking a virtual address instead of a relocation, and getSectionContaining for finding the section containing a certain virtual address) can be borrowed from ARMWinEHPrinter.

Adjust ARMWinEHPrinter to print the address of the exception handler routine as a VA instead of an RVA, consistently with other addresses in the same printout, and make Win64EHDumper print addresses similarly for image cases.

[rnk]

lgtm

llvm/test/tools/llvm-readobj/COFF/lit.local.cfg

+config.suffixes.add('.yaml')

llvm/test/tools/llvm-readobj/COFF/unwind-arm64-image.yaml

+# RUN: yaml2obj %s > %t.exe
+# RUN: llvm-readobj --unwind %t.exe | FileCheck %s
+
+# CHECK:        RuntimeFunction {
+# CHECK:          Function: entry (0x140001014)
+# CHECK-NEXT:     ExceptionRecord: 0x140002018
+# CHECK-NEXT:     ExceptionData {
+# CHECK-NEXT:       FunctionLength: 92
+# CHECK-NEXT:       Version: 0
+# CHECK-NEXT:       ExceptionData: Yes
+# CHECK-NEXT:       EpiloguePacked: No
+# CHECK-NEXT:       EpilogueScopes: 1
+# CHECK-NEXT:       ByteCodeLength: 8
+# CHECK-NEXT:       Prologue [
+# CHECK-NEXT:         0xd2c4              ; str x30, [sp, #32]
+# CHECK-NEXT:         0x03                ; sub sp, #48
+# CHECK-NEXT:         0xe4                ; end
+# CHECK-NEXT:       ]
+# CHECK-NEXT:       EpilogueScopes [
+# CHECK-NEXT:         EpilogueScope {
+# CHECK-NEXT:           StartOffset: 11
+# CHECK-NEXT:           EpilogueStartIndex: 4
+# CHECK-NEXT:           Opcodes [
+# CHECK-NEXT:             0xd2c4              ; ldr x30, [sp, #32]
+# CHECK-NEXT:             0x03                ; add sp, #48
+# CHECK-NEXT:             0xe4                ; end
+# CHECK-NEXT:           ]
+# CHECK-NEXT:         }
+# CHECK-NEXT:       ]
+# CHECK-NEXT:       ExceptionHandler [
+# CHECK-NEXT:         Routine: __gxx_personality_seh0 (0x140001074)
+# CHECK-NEXT:         Parameter: 0x801FFFF
+# CHECK-NEXT:       ]
+# CHECK-NEXT:     }
+# CHECK-NEXT:   }
+
+--- !COFF
+OptionalHeader:
+  AddressOfEntryPoint: 4116
+  ImageBase:       5368709120
+  SectionAlignment: 4096
+  FileAlignment:   512
+  MajorOperatingSystemVersion: 6
+  MinorOperatingSystemVersion: 0
+  MajorImageVersion: 0
+  MinorImageVersion: 0
+  MajorSubsystemVersion: 6
+  MinorSubsystemVersion: 0
+  Subsystem:       IMAGE_SUBSYSTEM_WINDOWS_CUI
+  DLLCharacteristics: [ IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA, IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE, IMAGE_DLL_CHARACTERISTICS_NX_COMPAT, IMAGE_DLL_CHARACTERISTICS_TERMINAL_SERVER_AWARE ]
+  SizeOfStackReserve: 1048576
+  SizeOfStackCommit: 4096
+  SizeOfHeapReserve: 1048576
+  SizeOfHeapCommit: 4096
+  ExportTable:
+    RelativeVirtualAddress: 0
+    Size:            0
+  ImportTable:
+    RelativeVirtualAddress: 0
+    Size:            0
+  ResourceTable:
+    RelativeVirtualAddress: 0
+    Size:            0
+  ExceptionTable:
+    RelativeVirtualAddress: 12288
+    Size:            40
+  CertificateTable:
+    RelativeVirtualAddress: 0
+    Size:            0
+  BaseRelocationTable:
+    RelativeVirtualAddress: 0
+    Size:            0
+  Debug:
+    RelativeVirtualAddress: 0
+    Size:            0
+  Architecture:
+    RelativeVirtualAddress: 0
+    Size:            0
+  GlobalPtr:
+    RelativeVirtualAddress: 0
+    Size:            0
+  TlsTable:
+    RelativeVirtualAddress: 0
+    Size:            0
+  LoadConfigTable:
+    RelativeVirtualAddress: 0
+    Size:            0
+  BoundImport:
+    RelativeVirtualAddress: 0
+    Size:            0
+  IAT:
+    RelativeVirtualAddress: 0
+    Size:            0
+  DelayImportDescriptor:
+    RelativeVirtualAddress: 0
+    Size:            0
+  ClrRuntimeHeader:
+    RelativeVirtualAddress: 0
+    Size:            0
+header:
+  Machine:         IMAGE_FILE_MACHINE_ARM64
+  Characteristics: [ IMAGE_FILE_EXECUTABLE_IMAGE, IMAGE_FILE_LARGE_ADDRESS_AWARE ]
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    VirtualAddress:  4096
+    VirtualSize:     120
+    SectionData:     C0035FD6FF4300D1E00700F9FF430091C0035FD6FFC300D1FE1300F90800009008C10191E80300F9F6FFFF9701000014E07F0091080000900811009100013FD6FE1340F9FFC30091C0035FD6E00B00F9E10F00B9E07F0091080000900811009100013FD6E00B40F9E80340F900013FD6C0035FD6C0035FD6
+  - Name:            .rdata
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]
+    VirtualAddress:  8192
+    VirtualSize:     80
+    SectionData:     0100400800000000E4E3E3E3040040080200800001E401E4170050100B000001D2C403E4D2C403E474100000FFFF010810083800184400000100400800000000E4E3E3E30100400800000000E4E3E3E3
+  - Name:            .pdata
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]
+    VirtualAddress:  12288
+    VirtualSize:     40
+    SectionData:     0010000000200000041000000C200000141000001820000070100000382000007410000044200000
+symbols:
+  - Name:            .text
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            .xdata
+    Value:           0
+    SectionNumber:   2
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            .pdata
+    Value:           0
+    SectionNumber:   3
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            other
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            _ZN4RAIID2Ev
+    Value:           4
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            entry
+    Value:           20
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            _Unwind_Resume
+    Value:           112
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            _ZN4RAIID1Ev
+    Value:           4
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            __gxx_personality_seh0
+    Value:           116
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            GCC_except_table2
+    Value:           44
+    SectionNumber:   2
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+...

llvm/test/tools/llvm-readobj/COFF/unwind-x86_64-image.yaml

+# RUN: yaml2obj %s > %t.exe
+# RUN: llvm-readobj --unwind %t.exe | FileCheck %s
+
+# CHECK:         RuntimeFunction {
+# CHECK:          StartAddress: entry (0x140001020)
+# CHECK-NEXT:     EndAddress: (0x14000105C)
+# CHECK-NEXT:     UnwindInfoAddress: (0x140002008)
+# CHECK-NEXT:     UnwindInfo {
+# CHECK-NEXT:       Version: 1
+# CHECK-NEXT:       Flags [ (0x3)
+# CHECK-NEXT:         ExceptionHandler (0x1)
+# CHECK-NEXT:         TerminateHandler (0x2)
+# CHECK-NEXT:       ]
+# CHECK-NEXT:       PrologSize: 4
+# CHECK-NEXT:       FrameRegister: -
+# CHECK-NEXT:       FrameOffset: -
+# CHECK-NEXT:       UnwindCodeCount: 1
+# CHECK-NEXT:       UnwindCodes [
+# CHECK-NEXT:         0x04: ALLOC_SMALL size=56
+# CHECK-NEXT:       ]
+# CHECK-NEXT:       Handler: __gxx_personality_seh0 (0x140001070)
+# CHECK-NEXT:     }
+# CHECK-NEXT:   }
+
+--- !COFF
+OptionalHeader:
+  AddressOfEntryPoint: 4128
+  ImageBase:       5368709120
+  SectionAlignment: 4096
+  FileAlignment:   512
+  MajorOperatingSystemVersion: 6
+  MinorOperatingSystemVersion: 0
+  MajorImageVersion: 0
+  MinorImageVersion: 0
+  MajorSubsystemVersion: 6
+  MinorSubsystemVersion: 0
+  Subsystem:       IMAGE_SUBSYSTEM_WINDOWS_CUI
+  DLLCharacteristics: [ IMAGE_DLL_CHARACTERISTICS_HIGH_ENTROPY_VA, IMAGE_DLL_CHARACTERISTICS_DYNAMIC_BASE, IMAGE_DLL_CHARACTERISTICS_NX_COMPAT, IMAGE_DLL_CHARACTERISTICS_TERMINAL_SERVER_AWARE ]
+  SizeOfStackReserve: 1048576
+  SizeOfStackCommit: 4096
+  SizeOfHeapReserve: 1048576
+  SizeOfHeapCommit: 4096
+  ExportTable:
+    RelativeVirtualAddress: 0
+    Size:            0
+  ImportTable:
+    RelativeVirtualAddress: 0
+    Size:            0
+  ResourceTable:
+    RelativeVirtualAddress: 0
+    Size:            0
+  ExceptionTable:
+    RelativeVirtualAddress: 12288
+    Size:            24
+  CertificateTable:
+    RelativeVirtualAddress: 0
+    Size:            0
+  BaseRelocationTable:
+    RelativeVirtualAddress: 0
+    Size:            0
+  Debug:
+    RelativeVirtualAddress: 0
+    Size:            0
+  Architecture:
+    RelativeVirtualAddress: 0
+    Size:            0
+  GlobalPtr:
+    RelativeVirtualAddress: 0
+    Size:            0
+  TlsTable:
+    RelativeVirtualAddress: 0
+    Size:            0
+  LoadConfigTable:
+    RelativeVirtualAddress: 0
+    Size:            0
+  BoundImport:
+    RelativeVirtualAddress: 0
+    Size:            0
+  IAT:
+    RelativeVirtualAddress: 0
+    Size:            0
+  DelayImportDescriptor:
+    RelativeVirtualAddress: 0
+    Size:            0
+  ClrRuntimeHeader:
+    RelativeVirtualAddress: 0
+    Size:            0
+header:
+  Machine:         IMAGE_FILE_MACHINE_AMD64
+  Characteristics: [ IMAGE_FILE_EXECUTABLE_IMAGE, IMAGE_FILE_LARGE_ADDRESS_AWARE ]
+sections:
+  - Name:            .text
+    Characteristics: [ IMAGE_SCN_CNT_CODE, IMAGE_SCN_MEM_EXECUTE, IMAGE_SCN_MEM_READ ]
+    VirtualAddress:  4096
+    VirtualSize:     113
+    SectionData:     C3662E0F1F8400000000000F1F4400005048890C2458C3660F1F8400000000004883EC38E8D7FFFFFFE900000000488D4C2430E8D8FFFFFF904883C438C3488944242889542424488D4C2430E8BFFFFFFF488B4C2428E805000000CC0F1F4000C3662E0F1F8400000000000F1F440000C3
+  - Name:            .rdata
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]
+    VirtualAddress:  8192
+    VirtualSize:     32
+    SectionData:     0101010001020000190401000462000070100000FFFF010804051E0009330000
+  - Name:            .pdata
+    Characteristics: [ IMAGE_SCN_CNT_INITIALIZED_DATA, IMAGE_SCN_MEM_READ ]
+    VirtualAddress:  12288
+    VirtualSize:     24
+    SectionData:     101000001710000000200000201000005C10000008200000
+symbols:
+  - Name:            .text
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            .xdata
+    Value:           0
+    SectionNumber:   2
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            .pdata
+    Value:           0
+    SectionNumber:   3
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+  - Name:            other
+    Value:           0
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            _ZN4RAIID2Ev
+    Value:           16
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            entry
+    Value:           32
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            _ZN4RAIID1Ev
+    Value:           16
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            _Unwind_Resume
+    Value:           96
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            __gxx_personality_seh0
+    Value:           112
+    SectionNumber:   1
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_FUNCTION
+    StorageClass:    IMAGE_SYM_CLASS_EXTERNAL
+  - Name:            GCC_except_table2
+    Value:           20
+    SectionNumber:   2
+    SimpleType:      IMAGE_SYM_TYPE_NULL
+    ComplexType:     IMAGE_SYM_DTYPE_NULL
+    StorageClass:    IMAGE_SYM_CLASS_STATIC
+...

llvm/tools/llvm-readobj/ARMWinEHPrinter.cpp

for (const EpilogueScope ES : EpilogueScopes) {
       decodeOpcodes(XData.UnwindByteCode(),
                     isAArch64 ? ES.EpilogueStartIndexAArch64()
                               : ES.EpilogueStartIndexARM(),
                     /*Prologue=*/false);
     }
   }
 
   if (XData.X()) {
-    const uint32_t Address = XData.ExceptionHandlerRVA();
+    const uint64_t Address = COFF.getImageBase() + XData.ExceptionHandlerRVA();
     const uint32_t Parameter = XData.ExceptionHandlerParameter();
     const size_t HandlerOffset = HeaderWords(XData)
                                + (XData.E() ? 0 : XData.EpilogueCount())
                                + XData.CodeWords();
 
     ErrorOr<SymbolRef> Symbol = getRelocatedSymbol(
         COFF, Section, Offset + HandlerOffset * sizeof(uint32_t));
     if (!Symbol)
       Symbol = getSymbol(COFF, Address, /*FunctionOnly=*/true);
     if (!Symbol) {
       ListScope EHS(SW, "ExceptionHandler");
-      SW.printString("Routine", "(null)");
+      SW.printHex("Routine", Address);
+      SW.printHex("Parameter", Parameter);
       return true;
     }
 
     Expected<StringRef> Name = Symbol->getName();
     if (!Name) {
       std::string Buf;
       llvm::raw_string_ostream OS(Buf);
       logAllUnhandledErrors(Name.takeError(), OS);

 bool Decoder::dumpUnpackedEntry(const COFFObjectFile &COFF,
                                 const SectionRef Section, uint64_t Offset,
                                 unsigned Index, const RuntimeFunction &RF) {
   assert(RF.Flag() == RuntimeFunctionFlag::RFF_Unpacked &&
          "packed entry cannot be treated as an unpacked entry");
 
   ErrorOr<SymbolRef> Function = getRelocatedSymbol(COFF, Section, Offset);
   if (!Function)
-    Function = getSymbol(COFF, RF.BeginAddress, /*FunctionOnly=*/true);
+    Function = getSymbol(COFF, COFF.getImageBase() + RF.BeginAddress,
+                         /*FunctionOnly=*/true);
 
   ErrorOr<SymbolRef> XDataRecord = getRelocatedSymbol(COFF, Section, Offset + 4);
   if (!XDataRecord)
     XDataRecord = getSymbol(COFF, RF.ExceptionInformationRVA());
 
   if (!RF.BeginAddress && !Function)
     return false;
   if (!RF.UnwindData && !XDataRecord)

llvm/tools/llvm-readobj/Win64EHDumper.cpp

 //===- Win64EHDumper.cpp - Win64 EH Printer ---------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "Win64EHDumper.h"
+#include "Error.h"
 #include "llvm-readobj.h"
 #include "llvm/Object/COFF.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Format.h"
 
 using namespace llvm;
 using namespace llvm::object;
 using namespace llvm::Win64EH;
static unsigned getNumUsedSlots(const UnwindCode &UnwindCode) {
   case UOP_SaveNonVolBig:
   case UOP_SaveXMM128Big:
     return 3;
   case UOP_AllocLarge:
     return (UnwindCode.getOpInfo() == 0) ? 2 : 3;
   }
 }
 
+static std::error_code getSymbol(const COFFObjectFile &COFF, uint64_t VA,
+                                 object::SymbolRef &Sym) {
+  for (const auto &Symbol : COFF.symbols()) {
+    Expected<uint64_t> Address = Symbol.getAddress();
+    if (!Address)
+      return errorToErrorCode(Address.takeError());
+    if (*Address == VA) {
+      Sym = Symbol;
+      return readobj_error::success;
+    }
+  }
+  return readobj_error::unknown_symbol;
+}
+
 static std::string formatSymbol(const Dumper::Context &Ctx,
                                 const coff_section *Section, uint64_t Offset,
                                 uint32_t Displacement) {
   std::string Buffer;
   raw_string_ostream OS(Buffer);
 
   SymbolRef Symbol;
   if (!Ctx.ResolveSymbol(Section, Offset, Symbol, Ctx.UserData)) {
     Expected<StringRef> Name = Symbol.getName();
     if (Name) {
       OS << *Name;
       if (Displacement > 0)
         OS << format(" +0x%X (0x%" PRIX64 ")", Displacement, Offset);
       else
         OS << format(" (0x%" PRIX64 ")", Offset);
       return OS.str();
     } else {
       // TODO: Actually report errors helpfully.
       consumeError(Name.takeError());
     }
+  } else if (!getSymbol(Ctx.COFF, Ctx.COFF.getImageBase() + Displacement,
+                        Symbol)) {
+    Expected<StringRef> Name = Symbol.getName();
+    if (Name) {
+      OS << *Name;
+      OS << format(" (0x%" PRIX64 ")", Ctx.COFF.getImageBase() + Displacement);
+      return OS.str();
+    } else {
+      consumeError(Name.takeError());
+    }
   }
 
-  OS << format(" (0x%" PRIX64 ")", Offset);
+  if (Displacement > 0)
+    OS << format("(0x%" PRIX64 ")", Ctx.COFF.getImageBase() + Displacement);
+  else
+    OS << format("(0x%" PRIX64 ")", Offset);
   return OS.str();
 }
 
 static std::error_code resolveRelocation(const Dumper::Context &Ctx,
                                          const coff_section *Section,
                                          uint64_t Offset,
                                          const coff_section *&ResolvedSection,
                                          uint64_t &ResolvedAddress) {
static std::error_code resolveRelocation(const Dumper::Context &Ctx,
 
   Expected<section_iterator> SI = Symbol.getSection();
   if (!SI)
     return errorToErrorCode(SI.takeError());
   ResolvedSection = Ctx.COFF.getCOFFSection(**SI);
   return std::error_code();
 }
 
+static const object::coff_section *
+getSectionContaining(const COFFObjectFile &COFF, uint64_t VA) {
+  for (const auto &Section : COFF.sections()) {
+    uint64_t Address = Section.getAddress();
+    uint64_t Size = Section.getSize();
+
+    if (VA >= Address && (VA - Address) <= Size)
+      return COFF.getCOFFSection(Section);
+  }
+  return nullptr;
+}
+
 namespace llvm {
 namespace Win64EH {
 void Dumper::printRuntimeFunctionEntry(const Context &Ctx,
                                        const coff_section *Section,
                                        uint64_t Offset,
                                        const RuntimeFunction &RF) {
   SW.printString("StartAddress",
                  formatSymbol(Ctx, Section, Offset + 0, RF.StartAddress));

 
 void Dumper::printRuntimeFunction(const Context &Ctx,
                                   const coff_section *Section,
                                   uint64_t SectionOffset,
                                   const RuntimeFunction &RF) {
   DictScope RFS(SW, "RuntimeFunction");
   printRuntimeFunctionEntry(Ctx, Section, SectionOffset, RF);
 
-  const coff_section *XData;
+  const coff_section *XData = nullptr;
   uint64_t Offset;
   resolveRelocation(Ctx, Section, SectionOffset + 8, XData, Offset);
+  Offset = Offset + RF.UnwindInfoOffset;
+
+  if (!XData) {
+    uint64_t Address = Ctx.COFF.getImageBase() + RF.UnwindInfoOffset;
+    XData = getSectionContaining(Ctx.COFF, Address);
+    if (!XData)
+      return;
+    Offset = RF.UnwindInfoOffset - XData->VirtualAddress;
+  }
 
   ArrayRef<uint8_t> Contents;
   if (Error E = Ctx.COFF.getSectionContents(XData, Contents))
     reportError(std::move(E), Ctx.COFF.getFileName());
 
   if (Contents.empty())
     return;
 
-  Offset = Offset + RF.UnwindInfoOffset;
   if (Offset > Contents.size())
     return;
 
   const auto UI = reinterpret_cast<const UnwindInfo*>(Contents.data() + Offset);
   printUnwindInfo(Ctx, XData, Offset, *UI);
 }
 
 void Dumper::printData(const Context &Ctx) {