Add dump of Win64 EH unwind data.

The new command line option -unwind-info dumps the Win64 EH unwind
data to the console. This is a nice feature if you need to debug
generated EH data (e.g. from LLVM). Includes a test case.

Initial patch by João Matos, extensions and rework by Kai Nacke.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169415 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 391 insertions, 3 deletions

diff --git a/tools/llvm-objdump/CMakeLists.txt b/tools/llvm-objdump/CMakeLists.txt
index f3b2e1fe41..5001435e83 100644
--- a/tools/llvm-objdump/CMakeLists.txt
+++ b/tools/llvm-objdump/CMakeLists.txt
@@ -9,6 +9,7 @@ set(LLVM_LINK_COMPONENTS
 
 add_llvm_tool(llvm-objdump
   llvm-objdump.cpp
+  COFFDump.cpp
   MachODump.cpp
   MCFunction.cpp
   )
diff --git a/tools/llvm-objdump/COFFDump.cpp b/tools/llvm-objdump/COFFDump.cpp
new file mode 100644
index 0000000000..ed4d1c3344
--- /dev/null
+++ b/tools/llvm-objdump/COFFDump.cpp
@@ -0,0 +1,355 @@
+//===-- COFFDump.cpp - COFF-specific dumper ---------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// \brief This file implements the COFF-specific dumper for llvm-objdump.
+/// It outputs the Win64 EH data structures as plain text.
+/// The encoding of the unwind codes is decribed in MSDN:
+/// http://msdn.microsoft.com/en-us/library/ck9asaa9.aspx
+///
+//===----------------------------------------------------------------------===//
+
+#include "llvm-objdump.h"
+#include "llvm/Object/COFF.h"
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/system_error.h"
+#include "llvm/Support/Win64EH.h"
+#include <algorithm>
+#include <cstring>
+
+using namespace llvm;
+using namespace object;
+using namespace llvm::Win64EH;
+
+// Returns the name of the unwind code.
+static StringRef getUnwindCodeTypeName(uint8_t Code) {
+  switch(Code) {
+  default: llvm_unreachable("Invalid unwind code");
+  case UOP_PushNonVol: return "UOP_PushNonVol";
+  case UOP_AllocLarge: return "UOP_AllocLarge";
+  case UOP_AllocSmall: return "UOP_AllocSmall";
+  case UOP_SetFPReg: return "UOP_SetFPReg";
+  case UOP_SaveNonVol: return "UOP_SaveNonVol";
+  case UOP_SaveNonVolBig: return "UOP_SaveNonVolBig";
+  case UOP_SaveXMM128: return "UOP_SaveXMM128";
+  case UOP_SaveXMM128Big: return "UOP_SaveXMM128Big";
+  case UOP_PushMachFrame: return "UOP_PushMachFrame";
+  }
+}
+
+// Returns the name of a referenced register.
+static StringRef getUnwindRegisterName(uint8_t Reg) {
+  switch(Reg) {
+  default: llvm_unreachable("Invalid register");
+  case 0: return "RAX";
+  case 1: return "RCX";
+  case 2: return "RDX";
+  case 3: return "RBX";
+  case 4: return "RSP";
+  case 5: return "RBP";
+  case 6: return "RSI";
+  case 7: return "RDI";
+  case 8: return "R8";
+  case 9: return "R9";
+  case 10: return "R10";
+  case 11: return "R11";
+  case 12: return "R12";
+  case 13: return "R13";
+  case 14: return "R14";
+  case 15: return "R15";
+  }
+}
+
+// Calculates the number of array slots required for the unwind code.
+static unsigned getNumUsedSlots(const UnwindCode &UnwindCode) {
+  switch (UnwindCode.getUnwindOp()) {
+  default: llvm_unreachable("Invalid unwind code");
+  case UOP_PushNonVol:
+  case UOP_AllocSmall:
+  case UOP_SetFPReg:
+  case UOP_PushMachFrame:
+    return 1;
+  case UOP_SaveNonVol:
+  case UOP_SaveXMM128:
+    return 2;
+  case UOP_SaveNonVolBig:
+  case UOP_SaveXMM128Big:
+    return 3;
+  case UOP_AllocLarge:
+    return (UnwindCode.getOpInfo() == 0) ? 2 : 3;
+  }
+}
+
+// Prints one unwind code. Because an unwind code can occupy up to 3 slots in
+// the unwind codes array, this function requires that the correct number of
+// slots is provided.
+static void printUnwindCode(ArrayRef<UnwindCode> UCs) {
+  assert(UCs.size() >= getNumUsedSlots(UCs[0]));
+  outs() <<  format("    0x%02x: ", unsigned(UCs[0].u.CodeOffset))
+         << getUnwindCodeTypeName(UCs[0].getUnwindOp());
+  switch (UCs[0].getUnwindOp()) {
+  case UOP_PushNonVol:
+    outs() << " " << getUnwindRegisterName(UCs[0].getOpInfo());
+    break;
+  case UOP_AllocLarge:
+    if (UCs[0].getOpInfo() == 0) {
+      outs() << " " << UCs[1].FrameOffset;
+    } else {
+      outs() << " " << UCs[1].FrameOffset
+                       + (static_cast<uint32_t>(UCs[2].FrameOffset) << 16);
+    }
+    break;
+  case UOP_AllocSmall:
+    outs() << " " << ((UCs[0].getOpInfo() + 1) * 8);
+    break;
+  case UOP_SetFPReg:
+    outs() << " ";
+    break;
+  case UOP_SaveNonVol:
+    outs() << " " << getUnwindRegisterName(UCs[0].getOpInfo())
+           << format(" [0x%04x]", 8 * UCs[1].FrameOffset);
+    break;
+  case UOP_SaveNonVolBig:
+    outs() << " " << getUnwindRegisterName(UCs[0].getOpInfo())
+           << format(" [0x%08x]", UCs[1].FrameOffset
+                    + (static_cast<uint32_t>(UCs[2].FrameOffset) << 16));
+    break;
+  case UOP_SaveXMM128:
+    outs() << " XMM" << static_cast<uint32_t>(UCs[0].getOpInfo())
+           << format(" [0x%04x]", 16 * UCs[1].FrameOffset);
+    break;
+  case UOP_SaveXMM128Big:
+    outs() << " XMM" << UCs[0].getOpInfo()
+           << format(" [0x%08x]", UCs[1].FrameOffset
+                           + (static_cast<uint32_t>(UCs[2].FrameOffset) << 16));
+    break;
+  case UOP_PushMachFrame:
+    outs() << " " << (UCs[0].getOpInfo() ? "w/o" : "w")
+           << " error code";
+    break;
+  }
+  outs() << "\n";
+}
+
+static void printAllUnwindCodes(ArrayRef<UnwindCode> UCs) {
+  for (const UnwindCode *I = UCs.begin(), *E = UCs.end(); I < E; ) {
+    unsigned UsedSlots = getNumUsedSlots(*I);
+    if (UsedSlots > UCs.size()) {
+      outs() << "Unwind data corrupted: Encountered unwind op "
+             << getUnwindCodeTypeName((*I).getUnwindOp())
+             << " which requires " << UsedSlots
+             << " slots, but only " << UCs.size()
+             << " remaining in buffer";
+      return ;
+    }
+    printUnwindCode(ArrayRef<UnwindCode>(I, E));
+    I += UsedSlots;
+  }
+}
+
+// Given a symbol sym this functions returns the address and section of it.
+static error_code resolveSectionAndAddress(const COFFObjectFile *Obj,
+                                           const SymbolRef &Sym,
+                                           const coff_section *&ResolvedSection,
+                                           uint64_t &ResolvedAddr) {
+  if (error_code ec = Sym.getAddress(ResolvedAddr)) return ec;
+  section_iterator iter(Obj->begin_sections());
+  if (error_code ec = Sym.getSection(iter)) return ec;
+  ResolvedSection = Obj->getCOFFSection(iter);
+  return object_error::success;
+}
+
+// Given a vector of relocations for a section and an offset into this section
+// the function returns the symbol used for the relocation at the offset.
+static error_code resolveSymbol(const std::vector<RelocationRef> &Rels,
+                                uint64_t Offset, SymbolRef &Sym) {
+  for (std::vector<RelocationRef>::const_iterator I = Rels.begin(),
+                                                  E = Rels.end();
+                                                  I != E; ++I) {
+    uint64_t Ofs;
+    if (error_code ec = I->getOffset(Ofs)) return ec;
+    if (Ofs == Offset) {
+      if (error_code ec = I->getSymbol(Sym)) return ec;
+      break;
+    }
+  }
+  return object_error::success;
+}
+
+// Given a vector of relocations for a section and an offset into this section
+// the function resolves the symbol used for the relocation at the offset and
+// returns the section content and the address inside the content pointed to
+// by the symbol.
+static error_code getSectionContents(const COFFObjectFile *Obj,
+                                     const std::vector<RelocationRef> &Rels,
+                                     uint64_t Offset,
+                                     ArrayRef<uint8_t> &Contents,
+                                     uint64_t &Addr) {
+  SymbolRef Sym;
+  if (error_code ec = resolveSymbol(Rels, Offset, Sym)) return ec;
+  const coff_section *Section;
+  if (error_code ec = resolveSectionAndAddress(Obj, Sym, Section, Addr))
+    return ec;
+  if (error_code ec = Obj->getSectionContents(Section, Contents)) return ec;
+  return object_error::success;
+}
+
+// Given a vector of relocations for a section and an offset into this section
+// the function returns the name of the symbol used for the relocation at the
+// offset.
+static error_code resolveSymbolName(const std::vector<RelocationRef> &Rels,
+                                    uint64_t Offset, StringRef &Name) {
+  SymbolRef Sym;
+  if (error_code ec = resolveSymbol(Rels, Offset, Sym)) return ec;
+  if (error_code ec = Sym.getName(Name)) return ec;
+  return object_error::success;
+}
+
+static void printCOFFSymbolAddress(llvm::raw_ostream &Out,
+                                   const std::vector<RelocationRef> &Rels,
+                                   uint64_t Offset, uint32_t Disp) {
+  StringRef Sym;
+  if (error_code ec = resolveSymbolName(Rels, Offset, Sym)) {
+    error(ec);
+    return ;
+  }
+  Out << Sym;
+  if (Disp > 0)
+    Out << format(" + 0x%04x", Disp);
+}
+
+void llvm::printCOFFUnwindInfo(const COFFObjectFile *Obj) {
+  const coff_file_header *Header;
+  if (error(Obj->getHeader(Header))) return;
+
+  if (Header->Machine != COFF::IMAGE_FILE_MACHINE_AMD64) {
+    errs() << "Unsupported image machine type "
+              "(currently only AMD64 is supported).\n";
+    return;
+  }
+
+  const coff_section *Pdata = 0;
+
+  error_code ec;
+  for (section_iterator SI = Obj->begin_sections(),
+                        SE = Obj->end_sections();
+                        SI != SE; SI.increment(ec)) {
+    if (error(ec)) return;
+
+    StringRef Name;
+    if (error(SI->getName(Name))) continue;
+
+    if (Name != ".pdata") continue;
+
+    Pdata = Obj->getCOFFSection(SI);
+    std::vector<RelocationRef> Rels;
+    for (relocation_iterator RI = SI->begin_relocations(),
+                             RE = SI->end_relocations();
+                             RI != RE; RI.increment(ec)) {
+      if (error(ec)) break;
+      Rels.push_back(*RI);
+    }
+
+    // Sort relocations by address.
+    std::sort(Rels.begin(), Rels.end(), RelocAddressLess);
+
+    ArrayRef<uint8_t> Contents;
+    if (error(Obj->getSectionContents(Pdata, Contents))) continue;
+    if (Contents.empty()) continue;
+
+    ArrayRef<RuntimeFunction> RFs(
+                  reinterpret_cast<const RuntimeFunction *>(Contents.data()),
+                                  Contents.size() / sizeof(RuntimeFunction));
+    for (const RuntimeFunction *I = RFs.begin(), *E = RFs.end(); I < E; ++I) {
+      const uint64_t SectionOffset = std::distance(RFs.begin(), I)
+                                     * sizeof(RuntimeFunction);
+
+      outs() << "Function Table:\n";
+
+      outs() << "  Start Address: ";
+      printCOFFSymbolAddress(outs(), Rels, SectionOffset +
+                             offsetof(RuntimeFunction, StartAddress),
+                             I->StartAddress);
+      outs() << "\n";
+
+      outs() << "  End Address: ";
+      printCOFFSymbolAddress(outs(), Rels, SectionOffset +
+                             offsetof(RuntimeFunction, EndAddress),
+                             I->EndAddress);
+      outs() << "\n";
+
+      outs() << "  Unwind Info Address: ";
+      printCOFFSymbolAddress(outs(), Rels, SectionOffset +
+                             offsetof(RuntimeFunction, UnwindInfoOffset),
+                             I->UnwindInfoOffset);
+      outs() << "\n";
+
+      ArrayRef<uint8_t> XContents;
+      uint64_t UnwindInfoOffset = 0;
+      if (error(getSectionContents(Obj, Rels, SectionOffset +
+                                   offsetof(RuntimeFunction, UnwindInfoOffset),
+                                   XContents, UnwindInfoOffset))) continue;
+      if (XContents.empty()) continue;
+
+      UnwindInfoOffset += I->UnwindInfoOffset;
+      if (UnwindInfoOffset > XContents.size()) continue;
+
+      const Win64EH::UnwindInfo *UI =
+                            reinterpret_cast<const Win64EH::UnwindInfo *>
+                              (XContents.data() + UnwindInfoOffset);
+
+      // The casts to int are required in order to output the value as number.
+      // Without the casts the value would be interpreted as char data (which
+      // results in garbage output).
+      outs() << "  Version: " << static_cast<int>(UI->getVersion()) << "\n";
+      outs() << "  Flags: " << static_cast<int>(UI->getFlags());
+      if (UI->getFlags()) {
+          if (UI->getFlags() & UNW_ExceptionHandler)
+            outs() << " UNW_ExceptionHandler";
+          if (UI->getFlags() & UNW_TerminateHandler)
+            outs() << " UNW_TerminateHandler";
+          if (UI->getFlags() & UNW_ChainInfo)
+            outs() << " UNW_ChainInfo";
+      }
+      outs() << "\n";
+      outs() << "  Size of prolog: "
+             << static_cast<int>(UI->PrologSize) << "\n";
+      outs() << "  Number of Codes: "
+             << static_cast<int>(UI->NumCodes) << "\n";
+      // Maybe this should move to output of UOP_SetFPReg?
+      if (UI->getFrameRegister()) {
+        outs() << "  Frame register: "
+                << getUnwindRegisterName(UI->getFrameRegister())
+                << "\n";
+        outs() << "  Frame offset: "
+                << 16 * UI->getFrameOffset()
+                << "\n";
+      } else {
+        outs() << "  No frame pointer used\n";
+      }
+      if (UI->getFlags() & (UNW_ExceptionHandler | UNW_TerminateHandler)) {
+        // FIXME: Output exception handler data
+      } else if (UI->getFlags() & UNW_ChainInfo) {
+        // FIXME: Output chained unwind info
+      }
+
+      if (UI->NumCodes)
+        outs() << "  Unwind Codes:\n";
+
+      printAllUnwindCodes(ArrayRef<UnwindCode>(&UI->UnwindCodes[0],
+                          UI->NumCodes));
+
+      outs() << "\n\n";
+      outs().flush();
+    }
+  }
+}
diff --git a/tools/llvm-objdump/llvm-objdump.cpp b/tools/llvm-objdump/llvm-objdump.cpp
index f1749f031b..2838a2a2b3 100644
--- a/tools/llvm-objdump/llvm-objdump.cpp
+++ b/tools/llvm-objdump/llvm-objdump.cpp
@@ -104,9 +104,16 @@ static cl::opt<bool>
 NoShowRawInsn("no-show-raw-insn", cl::desc("When disassembling instructions, "
                                            "do not print the instruction bytes."));
 
+static cl::opt<bool>
+UnwindInfo("unwind-info", cl::desc("Display unwind information"));
+
+static cl::alias
+UnwindInfoShort("u", cl::desc("Alias for --unwind-info"),
+                cl::aliasopt(UnwindInfo));
+
 static StringRef ToolName;
 
-static bool error(error_code ec) {
+bool llvm::error(error_code ec) {
   if (!ec) return false;
 
   outs() << ToolName << ": error reading file: " << ec.message() << ".\n";
@@ -165,7 +172,7 @@ void llvm::DumpBytes(StringRef bytes) {
   outs() << output;
 }
 
-static bool RelocAddressLess(RelocationRef a, RelocationRef b) {
+bool llvm::RelocAddressLess(RelocationRef a, RelocationRef b) {
   uint64_t a_addr, b_addr;
   if (error(a.getAddress(a_addr))) return false;
   if (error(b.getAddress(b_addr))) return false;
@@ -573,6 +580,19 @@ static void PrintSymbolTable(const ObjectFile *o) {
   }
 }
 
+static void PrintUnwindInfo(const ObjectFile *o) {
+  outs() << "Unwind info:\n\n";
+
+  if (const COFFObjectFile *coff = dyn_cast<COFFObjectFile>(o)) {
+    printCOFFUnwindInfo(coff);
+  } else {
+    // TODO: Extract DWARF dump tool to objdump.
+    errs() << "This operation is only currently supported "
+              "for COFF object files.\n";
+    return;
+  }
+}
+
 static void DumpObject(const ObjectFile *o) {
   outs() << '\n';
   outs() << o->getFileName()
@@ -588,6 +608,8 @@ static void DumpObject(const ObjectFile *o) {
     PrintSectionContents(o);
   if (SymbolTable)
     PrintSymbolTable(o);
+  if (UnwindInfo)
+    PrintUnwindInfo(o);
 }
 
 /// @brief Dump each object file in \a a;
@@ -666,7 +688,8 @@ int main(int argc, char **argv) {
       && !Relocations
       && !SectionHeaders
       && !SectionContents
-      && !SymbolTable) {
+      && !SymbolTable
+      && !UnwindInfo) {
     cl::PrintHelpMessage();
     return 2;
   }
diff --git a/tools/llvm-objdump/llvm-objdump.h b/tools/llvm-objdump/llvm-objdump.h
index aa71b77c8a..9f5a8c3db9 100644
--- a/tools/llvm-objdump/llvm-objdump.h
+++ b/tools/llvm-objdump/llvm-objdump.h
@@ -17,12 +17,21 @@
 
 namespace llvm {
 
+namespace object {
+  class COFFObjectFile;
+  class RelocationRef;
+}
+class error_code;
+
 extern cl::opt<std::string> TripleName;
 extern cl::opt<std::string> ArchName;
 
 // Various helper functions.
+bool error(error_code ec);
+bool RelocAddressLess(object::RelocationRef a, object::RelocationRef b);
 void DumpBytes(StringRef bytes);
 void DisassembleInputMachO(StringRef Filename);
+void printCOFFUnwindInfo(const object::COFFObjectFile* o);
 
 class StringRefMemoryObject : public MemoryObject {
   virtual void anchor();