Reland "[DebugInfo] Support DWARF expressions in eh_frame"

Summary:
Original change was D43313 (r326932) and reverted by r326953 because it
broke an LLD test and a windows build. The LLD test was already fixed in
lld commit r326944 (thanks maskray). This is the original change with
the windows build fixed.

llvm-svn: 326970

3 files changed, 251 insertions, 0 deletions

diff --git a/llvm/tools/llvm-readobj/CMakeLists.txt b/llvm/tools/llvm-readobj/CMakeLists.txt
index dafc9e10cfa..b0550f34012 100644
--- a/llvm/tools/llvm-readobj/CMakeLists.txt
+++ b/llvm/tools/llvm-readobj/CMakeLists.txt
@@ -1,5 +1,6 @@
 set(LLVM_LINK_COMPONENTS
   DebugInfoCodeView
+  DebugInfoDWARF
   Object
   BinaryFormat
   Support
diff --git a/llvm/tools/llvm-readobj/DwarfCFIEHPrinter.h b/llvm/tools/llvm-readobj/DwarfCFIEHPrinter.h
new file mode 100644
index 00000000000..6f1e35ced94
--- /dev/null
+++ b/llvm/tools/llvm-readobj/DwarfCFIEHPrinter.h
@@ -0,0 +1,244 @@
+//===--- DwarfCFIEHPrinter.h - DWARF-based Unwind Information Printer -----===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TOOLS_LLVM_READOBJ_DWARFCFIEHPRINTER_H
+#define LLVM_TOOLS_LLVM_READOBJ_DWARFCFIEHPRINTER_H
+
+#include "Error.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/BinaryFormat/Dwarf.h"
+#include "llvm/Object/ELF.h"
+#include "llvm/Object/ELFTypes.h"
+#include "llvm/Support/Casting.h"
+#include "llvm/Support/ScopedPrinter.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugFrame.h"
+#include "llvm/Support/Endian.h"
+#include "llvm/Support/Format.h"
+#include "llvm/Support/type_traits.h"
+
+namespace llvm {
+namespace DwarfCFIEH {
+
+template <typename ELFT>
+class PrinterContext {
+  ScopedPrinter &W;
+  const object::ELFFile<ELFT> *Obj;
+
+  void printEHFrameHdr(uint64_t Offset, uint64_t Address, uint64_t Size) const;
+
+  void printEHFrame(const typename ELFT::Shdr *EHFrameShdr) const;
+
+public:
+  PrinterContext(ScopedPrinter &W, const object::ELFFile<ELFT> *Obj)
+      : W(W), Obj(Obj) {}
+
+  void printUnwindInformation() const;
+};
+
+template <class ELFO>
+static const typename ELFO::Elf_Shdr *findSectionByAddress(const ELFO *Obj,
+                                                           uint64_t Addr) {
+  auto Sections = Obj->sections();
+  if (Error E = Sections.takeError())
+    reportError(toString(std::move(E)));
+
+  for (const auto &Shdr : *Sections)
+    if (Shdr.sh_addr == Addr)
+      return &Shdr;
+  return nullptr;
+}
+
+template <typename ELFT>
+void PrinterContext<ELFT>::printUnwindInformation() const {
+  const typename ELFT::Phdr *EHFramePhdr = nullptr;
+
+  auto PHs = Obj->program_headers();
+  if (Error E = PHs.takeError())
+    reportError(toString(std::move(E)));
+
+  for (const auto &Phdr : *PHs) {
+    if (Phdr.p_type == ELF::PT_GNU_EH_FRAME) {
+      EHFramePhdr = &Phdr;
+      if (Phdr.p_memsz != Phdr.p_filesz)
+        reportError("p_memsz does not match p_filesz for GNU_EH_FRAME");
+      break;
+    }
+  }
+
+  if (EHFramePhdr)
+    printEHFrameHdr(EHFramePhdr->p_offset, EHFramePhdr->p_vaddr,
+                    EHFramePhdr->p_memsz);
+
+  auto Sections = Obj->sections();
+  if (Error E = Sections.takeError())
+    reportError(toString(std::move(E)));
+
+  for (const auto &Shdr : *Sections) {
+    auto SectionName = Obj->getSectionName(&Shdr);
+    if (Error E = SectionName.takeError())
+      reportError(toString(std::move(E)));
+
+    if (*SectionName == ".eh_frame")
+      printEHFrame(&Shdr);
+  }
+}
+
+template <typename ELFT>
+void PrinterContext<ELFT>::printEHFrameHdr(uint64_t EHFrameHdrOffset,
+                                           uint64_t EHFrameHdrAddress,
+                                           uint64_t EHFrameHdrSize) const {
+  ListScope L(W, "EH_FRAME Header");
+  W.startLine() << format("Address: 0x%" PRIx64 "\n", EHFrameHdrAddress);
+  W.startLine() << format("Offset: 0x%" PRIx64 "\n", EHFrameHdrOffset);
+  W.startLine() << format("Size: 0x%" PRIx64 "\n", EHFrameHdrSize);
+
+  const auto *EHFrameHdrShdr = findSectionByAddress(Obj, EHFrameHdrAddress);
+  if (EHFrameHdrShdr) {
+    auto SectionName = Obj->getSectionName(EHFrameHdrShdr);
+    if (Error E = SectionName.takeError())
+      reportError(toString(std::move(E)));
+
+    W.printString("Corresponding Section", *SectionName);
+  }
+
+  DataExtractor DE(
+      StringRef(reinterpret_cast<const char *>(Obj->base()) + EHFrameHdrOffset,
+                EHFrameHdrSize),
+      ELFT::TargetEndianness == support::endianness::little,
+      ELFT::Is64Bits ? 8 : 4);
+
+  DictScope D(W, "Header");
+  uint32_t Offset = 0;
+
+  auto Version = DE.getU8(&Offset);
+  W.printNumber("version", Version);
+  if (Version != 1)
+    reportError("only version 1 of .eh_frame_hdr is supported");
+
+  uint64_t EHFramePtrEnc = DE.getU8(&Offset);
+  W.startLine() << format("eh_frame_ptr_enc: 0x%" PRIx64 "\n", EHFramePtrEnc);
+  if (EHFramePtrEnc != (dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4))
+    reportError("unexpected encoding eh_frame_ptr_enc");
+
+  uint64_t FDECountEnc = DE.getU8(&Offset);
+  W.startLine() << format("fde_count_enc: 0x%" PRIx64 "\n", FDECountEnc);
+  if (FDECountEnc != dwarf::DW_EH_PE_udata4)
+    reportError("unexpected encoding fde_count_enc");
+
+  uint64_t TableEnc = DE.getU8(&Offset);
+  W.startLine() << format("table_enc: 0x%" PRIx64 "\n", TableEnc);
+  if (TableEnc != (dwarf::DW_EH_PE_datarel | dwarf::DW_EH_PE_sdata4))
+    reportError("unexpected encoding table_enc");
+
+  auto EHFramePtr = DE.getSigned(&Offset, 4) + EHFrameHdrAddress + 4;
+  W.startLine() << format("eh_frame_ptr: 0x%" PRIx64 "\n", EHFramePtr);
+
+  auto FDECount = DE.getUnsigned(&Offset, 4);
+  W.printNumber("fde_count", FDECount);
+
+  unsigned NumEntries = 0;
+  uint64_t PrevPC = 0;
+  while (Offset + 8 <= EHFrameHdrSize && NumEntries < FDECount) {
+    DictScope D(W, std::string("entry ")  + std::to_string(NumEntries));
+
+    auto InitialPC = DE.getSigned(&Offset, 4) + EHFrameHdrAddress;
+    W.startLine() << format("initial_location: 0x%" PRIx64 "\n", InitialPC);
+    auto Address = DE.getSigned(&Offset, 4) + EHFrameHdrAddress;
+    W.startLine() << format("address: 0x%" PRIx64 "\n", Address);
+
+    if (InitialPC < PrevPC)
+      reportError("initial_location is out of order");
+
+    PrevPC = InitialPC;
+    ++NumEntries;
+  }
+}
+
+template <typename ELFT>
+void PrinterContext<ELFT>::printEHFrame(
+    const typename ELFT::Shdr *EHFrameShdr) const {
+  uint64_t Address = EHFrameShdr->sh_addr;
+  uint64_t ShOffset = EHFrameShdr->sh_offset;
+  W.startLine() << format(".eh_frame section at offset 0x%" PRIx64
+                          " address 0x%" PRIx64 ":\n",
+                          ShOffset, Address);
+  W.indent();
+
+  auto Result = Obj->getSectionContents(EHFrameShdr);
+  if (Error E = Result.takeError())
+    reportError(toString(std::move(E)));
+
+  auto Contents = Result.get();
+  DWARFDataExtractor DE(
+      StringRef(reinterpret_cast<const char *>(Contents.data()),
+                Contents.size()),
+      ELFT::TargetEndianness == support::endianness::little,
+      ELFT::Is64Bits ? 8 : 4);
+  DWARFDebugFrame EHFrame(/*IsEH=*/true, /*EHFrameAddress=*/Address);
+  EHFrame.parse(DE);
+
+  for (const auto &Entry : EHFrame) {
+    if (const auto *CIE = dyn_cast<dwarf::CIE>(&Entry)) {
+      W.startLine() << format("[0x%" PRIx64 "] CIE length=%" PRIu64 "\n",
+                              Address + CIE->getOffset(),
+                              CIE->getLength());
+      W.indent();
+
+      W.printNumber("version", CIE->getVersion());
+      W.printString("augmentation", CIE->getAugmentationString());
+      W.printNumber("code_alignment_factor", CIE->getCodeAlignmentFactor());
+      W.printNumber("data_alignment_factor", CIE->getDataAlignmentFactor());
+      W.printNumber("return_address_register", CIE->getReturnAddressRegister());
+
+      W.getOStream() << "\n";
+      W.startLine() << "Program:\n";
+      W.indent();
+      CIE->cfis().dump(W.getOStream(), nullptr, W.getIndentLevel());
+      W.unindent();
+
+      W.unindent();
+      W.getOStream() << "\n";
+
+    } else if (const auto *FDE = dyn_cast<dwarf::FDE>(&Entry)) {
+      W.startLine() << format("[0x%" PRIx64 "] FDE length=%" PRIu64
+                              " cie=[0x%" PRIx64 "]\n",
+                              Address + FDE->getOffset(),
+                              FDE->getLength(),
+                              Address + FDE->getLinkedCIE()->getOffset());
+      W.indent();
+
+      W.startLine() << format("initial_location: 0x%" PRIx64 "\n",
+                              FDE->getInitialLocation());
+      W.startLine()
+        << format("address_range: 0x%" PRIx64 " (end : 0x%" PRIx64 ")\n",
+                  FDE->getAddressRange(),
+                  FDE->getInitialLocation() + FDE->getAddressRange());
+
+      W.getOStream() << "\n";
+      W.startLine() << "Program:\n";
+      W.indent();
+      FDE->cfis().dump(W.getOStream(), nullptr, W.getIndentLevel());
+      W.unindent();
+
+      W.unindent();
+      W.getOStream() << "\n";
+    } else {
+      llvm_unreachable("unexpected DWARF frame kind");
+    }
+  }
+
+  W.unindent();
+}
+
+}
+}
+
+#endif
diff --git a/llvm/tools/llvm-readobj/ELFDumper.cpp b/llvm/tools/llvm-readobj/ELFDumper.cpp
index 36cda459225..6b6582b7566 100644
--- a/llvm/tools/llvm-readobj/ELFDumper.cpp
+++ b/llvm/tools/llvm-readobj/ELFDumper.cpp
@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "ARMEHABIPrinter.h"
+#include "DwarfCFIEHPrinter.h"
 #include "Error.h"
 #include "ObjDumper.h"
 #include "StackMapPrinter.h"
@@ -1808,6 +1809,11 @@ void ELFDumper<ELFT>::printValue(uint64_t Type, uint64_t Value) {
 
 template<class ELFT>
 void ELFDumper<ELFT>::printUnwindInfo() {
+  const unsigned Machine = Obj->getHeader()->e_machine;
+  if (Machine == EM_386 || Machine == EM_X86_64) {
+    DwarfCFIEH::PrinterContext<ELFT> Ctx(W, Obj);
+    return Ctx.printUnwindInformation();
+  }
   W.startLine() << "UnwindInfo not implemented.\n";
 }