Revert "[lld-macho] Initial support for EH Frames"

This reverts commit 826be33.

This was causing a test failure on build bots:
  - https://lab.llvm.org/buildbot/#/builders/36/builds/21770
  - https://lab.llvm.org/buildbot/#/builders/58/builds/23913

Author: dyung

lld/MachO/Arch/ARM64.cpp

@@ -13,7 +13,6 @@
 #include "Target.h"
 
 #include "lld/Common/ErrorHandler.h"
-#include "mach-o/compact_unwind_encoding.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/BinaryFormat/MachO.h"
@@ -142,10 +141,6 @@ ARM64::ARM64() : ARM64Common(LP64()) {
   backwardBranchRange = 128 * 1024 * 1024;
   forwardBranchRange = backwardBranchRange - 4;
 
-  modeDwarfEncoding = UNWIND_ARM64_MODE_DWARF;
-  subtractorRelocType = ARM64_RELOC_SUBTRACTOR;
-  unsignedRelocType = ARM64_RELOC_UNSIGNED;
-
   stubHelperHeaderSize = sizeof(stubHelperHeaderCode);
   stubHelperEntrySize = sizeof(stubHelperEntryCode);
 }

lld/MachO/Arch/ARM64_32.cpp

@@ -105,10 +105,6 @@ ARM64_32::ARM64_32() : ARM64Common(ILP32()) {
   cpuType = CPU_TYPE_ARM64_32;
   cpuSubtype = CPU_SUBTYPE_ARM64_V8;
 
-  modeDwarfEncoding = 0x04000000;              // UNWIND_ARM_MODE_DWARF
-  subtractorRelocType = GENERIC_RELOC_INVALID; // FIXME
-  unsignedRelocType = GENERIC_RELOC_INVALID;   // FIXME
-
   stubSize = sizeof(stubCode);
   stubHelperHeaderSize = sizeof(stubHelperHeaderCode);
   stubHelperEntrySize = sizeof(stubHelperEntryCode);

lld/MachO/Arch/X86_64.cpp

@@ -12,7 +12,6 @@
 #include "Target.h"
 
 #include "lld/Common/ErrorHandler.h"
-#include "mach-o/compact_unwind_encoding.h"
 #include "llvm/BinaryFormat/MachO.h"
 #include "llvm/Support/Endian.h"
 
@@ -186,10 +185,6 @@ X86_64::X86_64() : TargetInfo(LP64()) {
   cpuType = CPU_TYPE_X86_64;
   cpuSubtype = CPU_SUBTYPE_X86_64_ALL;
 
-  modeDwarfEncoding = UNWIND_X86_MODE_DWARF;
-  subtractorRelocType = X86_64_RELOC_SUBTRACTOR;
-  unsignedRelocType = X86_64_RELOC_UNSIGNED;
-
   stubSize = sizeof(stub);
   stubHelperHeaderSize = sizeof(stubHelperHeader);
   stubHelperEntrySize = sizeof(stubHelperEntry);

lld/MachO/CMakeLists.txt

@@ -14,7 +14,6 @@ add_lld_library(lldMachO
   Driver.cpp
   DriverUtils.cpp
   Dwarf.cpp
-  EhFrame.cpp
   ExportTrie.cpp
   ICF.cpp
   InputFiles.cpp

lld/MachO/Config.h

@@ -130,9 +130,6 @@ struct Configuration {
   bool dedupLiterals = true;
   bool omitDebugInfo = false;
   bool warnDylibInstallName = false;
-  // Temporary config flag that will be removed once we have fully implemented
-  // support for __eh_frame.
-  bool parseEhFrames = false;
   uint32_t headerPad;
   uint32_t dylibCompatibilityVersion = 0;
   uint32_t dylibCurrentVersion = 0;

lld/MachO/Driver.cpp

@@ -1039,9 +1039,8 @@ static void gatherInputSections() {
   int inputOrder = 0;
   for (const InputFile *file : inputFiles) {
     for (const Section *section : file->sections) {
-      // Compact unwind entries require special handling elsewhere. (In
-      // contrast, EH frames are handled like regular ConcatInputSections.)
       if (section->name == section_names::compactUnwind)
+        // Compact unwind entries require special handling elsewhere.
         continue;
       ConcatOutputSection *osec = nullptr;
       for (const Subsection &subsection : section->subsections) {
@@ -1303,7 +1302,6 @@ bool macho::link(ArrayRef<const char *> argsArr, llvm::raw_ostream &stdoutOS,
   config->callGraphProfileSort = args.hasFlag(
       OPT_call_graph_profile_sort, OPT_no_call_graph_profile_sort, true);
   config->printSymbolOrder = args.getLastArgValue(OPT_print_symbol_order);
-  config->parseEhFrames = static_cast<bool>(getenv("LLD_IN_TEST"));
 
   // FIXME: Add a commandline flag for this too.
   config->zeroModTime = getenv("ZERO_AR_DATE");

lld/MachO/EhFrame.cpp

@@ -212,9 +212,9 @@ bool ICF::equalsVariable(const ConcatInputSection *ia,
   // info matches. For simplicity, we only handle the case where there are only
   // symbols at offset zero within the section (which is typically the case with
   // .subsections_via_symbols.)
-  auto hasUnwind = [](Defined *d) { return d->unwindEntry != nullptr; };
-  auto itA = std::find_if(ia->symbols.begin(), ia->symbols.end(), hasUnwind);
-  auto itB = std::find_if(ib->symbols.begin(), ib->symbols.end(), hasUnwind);
+  auto hasCU = [](Defined *d) { return d->unwindEntry != nullptr; };
+  auto itA = std::find_if(ia->symbols.begin(), ia->symbols.end(), hasCU);
+  auto itB = std::find_if(ib->symbols.begin(), ib->symbols.end(), hasCU);
   if (itA == ia->symbols.end())
     return itB == ib->symbols.end();
   if (itB == ib->symbols.end())