Fixing DWARFExpression handling of ValueType::FileAddress case for DW_OP_deref_size

[shafik]

Summary

Currently DW_OP_deref_size just drops the ValueType::FileAddress case and does not attempt to handle it. This adds support for this case and a test that verifies this support.

I did a little refactoring since DW_OP_deref and DW_OP_deref_size have some overlap in code.

[shafik]

There can probably be some more refactoring wrt to the Value class which also does a lot of the same work but there are enough differences that I think any attempt at that should be left for a separate PR.

[aprantl]

This is nice, I have a few mostly stylistic comments inline.

lldb/source/Expression/DWARFExpression.cpp

947

Maybe add a Doxygen comment explaining what this function does?

948

Should this also be in the anonymous namespace?

964

return so_addr.GetLoadAddress(exe_ctx->GetTargetPtr();
or load_addr

977

the break is redundant after the return.

990

This shouldn't be necessary, or does clang warn about the function not having a return on this otherwise?

1168–1169

why is Addr captialized?

1168–1169

we sometimes call these maybe_load_addr or load_addr_or_err not sure if that's better :-)

1168–1169

should we sink this check into ResolveAndLoadFileAddress, too?

1299

Comment what this case handles? It's unintuitive that we go into a case where load_Addr == LLDB_INVALID_ADDRESS

1303

Why do we need to force live memory?

1314

It would be nice to invert the if and have an early exit instead.

1320

same here, but maybe we can just sink this into the helper.

[aprantl]

lldb/test/Shell/SymbolFile/DWARF/x86/DW_OP_deref_size_static_var.s

2

Out of curiosity: Does the x86 directory's lit.cfg require a compiler with with an x86 *backend*, or an x86 *host*?

[shafik]

Addressing comment

• Adding documentation
• Moving some more error handling into helper
• Cleaning up the calling side

[shafik]

lldb/source/Expression/DWARFExpression.cpp

948

Good catch although static is probably more appropriate: https://llvm.org/docs/CodingStandards.html#anonymous-namespaces

1168–1169

load_Addr was what it was before, I didn't even notice it.

1303

Good catch, we don't.

1320

Makes sense, it was a little tricky but I think with these changes it is neater.

[aprantl]

Thanks!

lldb/source/Expression/DWARFExpression.cpp

962

Thanks! I would have been happy with just the function description ;-)

1362–1363

Why is this commented out?

[shafik]

Removing dead code.

[shafik]

Fixing up diff

[saugustine]

This change uses a variable-sized array, which is c99 only:

third_party/llvm/llvm-project/lldb/source/Expression/DWARFExpression.cpp:1300:30: error: variable length arrays are a C99 feature [-Werror,-Wvla-extension]
          uint8_t addr_bytes[size];
                             ^~~~
third_party/llvm/llvm-project/lldb/source/Expression/DWARFExpression.cpp:1300:30: note: read of non-const variable 'size' is not allowed in a constant expression
third_party/llvm/llvm-project/lldb/source/Expression/DWARFExpression.cpp:1242:15: note: declared here
      uint8_t size = opcodes.GetU8(&offset);

But I the size of the array is limited to only to the address size of the target machine, so converting that to a simple eight-byte array and then using size instead of sizeof(addr_bytes) should be fine. I have a change in testing to do that.

[saugustine]

Fix for the variable-sized-array issue in rG7518e0ff63cd

[clayborg]

Sorry for the late comments. Looks like it got checked in already, but will submit inline comments anyway.

lldb/source/Expression/DWARFExpression.cpp

964

Pass the module_sp in as a reference to avoid the increment/decrement on the reference count?

964

Maybe "ResolveLoadAddress" would be a better name?

972

Do we prefer "return {}" over "return llvm::None"?

984

Not sure if you need to do this as the call to "module_sp->ResolveFileAddress(...) will return false if the address wasn't resolved to a address that is section offset.

1007–1018

DataExtractor already has a GetMaxU64() call you can use. It handles anything <= 8 bytes in size. Do we really want to handle the "default:" case above or the "else" clause in my suggested fix though?

1103

revert

[aprantl]

lldb/source/Expression/DWARFExpression.cpp

972

Personally, I do, but there's no rule about that.

lldb/source/Expression/DWARFExpression.cpp

case Implicit:
       if (value->GetValueType() == Value::ValueType::LoadAddress)
         value->SetValueType(Value::ValueType::Scalar);
       break;
     }
   }
 }
 } // namespace
 
+/// Helper function to move common code used to resolve a file address and turn
+/// into a load address.
+///
+/// \param exe_ctx Pointer to the execution context
+/// \param module_sp shared_ptr contains the module if we have one
+/// \param error_ptr pointer to Status object if we have one
+/// \param dw_op_type C-style string used to vary the error output
+/// \param file_addr the file address we are trying to resolve and turn into a
+///                  load address
+/// \param so_addr out parameter, will be set to load addresss or section offset
+/// \param check_sectionoffset bool which determines if having a section offset
+///                            but not a load address is considerd a success
+/// \returns llvm::Optional containing the load address if resolving and getting
+///          the load address succeed or an empty Optinal otherwise. If
+///          check_sectionoffset is true we consider LLDB_INVALID_ADDRESS a
+///          success if so_addr.IsSectionOffset() is true.
+static llvm::Optional<lldb::addr_t>
+ResolveAndLoadFileAddress(ExecutionContext *exe_ctx, lldb::ModuleSP module_sp,
+                          Status *error_ptr, const char *dw_op_type,
+                          lldb::addr_t file_addr, Address &so_addr,
+                          bool check_sectionoffset = false) {
+  if (!module_sp) {
+    if (error_ptr)
+      error_ptr->SetErrorStringWithFormat(
+          "need module to resolve file address for %s", dw_op_type);
+    return {};
+  }
+
+  if (!module_sp->ResolveFileAddress(file_addr, so_addr)) {
+    if (error_ptr)
+      error_ptr->SetErrorString("failed to resolve file address in module");
+    return {};
+  }
+
+  addr_t load_addr = so_addr.GetLoadAddress(exe_ctx->GetTargetPtr());
+
+  if (load_addr == LLDB_INVALID_ADDRESS &&
+      (check_sectionoffset && !so_addr.IsSectionOffset())) {
+    if (error_ptr)
+      error_ptr->SetErrorString("failed to resolve load address");
+    return {};
+  }
+
+  return load_addr;
+}
+
+/// Helper function to move common code used to load sized data from a uint8_t
+/// buffer.
+///
+/// \param addr_bytes uint8_t buffer containg raw data
+/// \param size_addr_bytes how large is the underlying raw data
+/// \param byte_order what is the byter order of the underlyig data
+/// \param size How much of the underlying data we want to use
+/// \return The underlying data converted into a Scalar
+static Scalar DerefSizeExtractDataHelper(uint8_t *addr_bytes,
+                                         size_t size_addr_bytes,
+                                         ByteOrder byte_order, size_t size) {
+  DataExtractor addr_data(addr_bytes, size_addr_bytes, byte_order, size);
+
+  lldb::offset_t addr_data_offset = 0;
+  switch (size) {
+  case 1:
+    return addr_data.GetU8(&addr_data_offset);
+  case 2:
+    return addr_data.GetU16(&addr_data_offset);
+  case 4:
+    return addr_data.GetU32(&addr_data_offset);
+  case 8:
+    return addr_data.GetU64(&addr_data_offset);
+  default:
+    return addr_data.GetAddress(&addr_data_offset);
+  }
+}
+
 bool DWARFExpression::Evaluate(
     ExecutionContext *exe_ctx, RegisterContext *reg_ctx,
     lldb::ModuleSP module_sp, const DataExtractor &opcodes,
     const DWARFUnit *dwarf_cu, const lldb::RegisterKind reg_kind,
     const Value *initial_value_ptr, const Value *object_address_ptr,
     Value &result, Status *error_ptr) {
 
   if (opcodes.GetByteSize() == 0) {
while (opcodes.ValidOffset(offset)) {
     case DW_OP_addr:
       stack.push_back(Scalar(opcodes.GetAddress(&offset)));
       stack.back().SetValueType(Value::ValueType::FileAddress);
       // Convert the file address to a load address, so subsequent
       // DWARF operators can operate on it.
       if (frame)
         stack.back().ConvertToLoadAddress(module_sp.get(),
                                           frame->CalculateTarget().get());
+
       break;
 
     // The DW_OP_addr_sect_offset4 is used for any location expressions in
     // shared libraries that have a location like:
     //  DW_OP_addr(0x1000)
     // If this address resides in a shared library, then this virtual address
     // won't make sense when it is evaluated in the context of a running
     // process where shared libraries have been slid. To account for this, this
case DW_OP_deref: {
         intptr_t ptr;
         ::memcpy(&ptr, src, sizeof(void *));
         stack.back().GetScalar() = ptr;
         stack.back().ClearContext();
       } break;
       case Value::ValueType::FileAddress: {
         auto file_addr = stack.back().GetScalar().ULongLong(
             LLDB_INVALID_ADDRESS);
-        if (!module_sp) {
-          if (error_ptr)
-            error_ptr->SetErrorString(
-                "need module to resolve file address for DW_OP_deref");
-          return false;
-        }
+
         Address so_addr;
-        if (!module_sp->ResolveFileAddress(file_addr, so_addr)) {
-          if (error_ptr)
-            error_ptr->SetErrorString(
-                "failed to resolve file address in module");
-          return false;
-        }
-        addr_t load_Addr = so_addr.GetLoadAddress(exe_ctx->GetTargetPtr());
-        if (load_Addr == LLDB_INVALID_ADDRESS) {
-          if (error_ptr)
-            error_ptr->SetErrorString("failed to resolve load address");
+        auto maybe_load_addr = ResolveAndLoadFileAddress(
+            exe_ctx, module_sp, error_ptr, "DW_OP_deref", file_addr, so_addr);
+
+        if (!maybe_load_addr)
           return false;
-        }
-        stack.back().GetScalar() = load_Addr;
+
+        stack.back().GetScalar() = *maybe_load_addr;
         // Fall through to load address promotion code below.
       } LLVM_FALLTHROUGH;
       case Value::ValueType::Scalar:
         // Promote Scalar to LoadAddress and fall through.
         stack.back().SetValueType(Value::ValueType::LoadAddress);
         LLVM_FALLTHROUGH;
       case Value::ValueType::LoadAddress:
         if (exe_ctx) {
case DW_OP_deref_size: {
           ptr = (intptr_t)ptr & 0xffffffffffffffULL;
           break;
         default:
           break;
         }
         stack.back().GetScalar() = ptr;
         stack.back().ClearContext();
       } break;
+      case Value::ValueType::FileAddress: {
+        auto file_addr =
+            stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
+        Address so_addr;
+        auto maybe_load_addr =
+            ResolveAndLoadFileAddress(exe_ctx, module_sp, error_ptr,
+                                      "DW_OP_deref_size", file_addr, so_addr,
+                                      /*check_sectionoffset=*/true);
+
+        if (!maybe_load_addr)
+          return false;
+
+        addr_t load_addr = *maybe_load_addr;
+
+        if (load_addr == LLDB_INVALID_ADDRESS && so_addr.IsSectionOffset()) {
+          uint8_t addr_bytes[size];
+          Status error;
+
+          if (exe_ctx->GetTargetRef().ReadMemory(
+                  so_addr, &addr_bytes, size, error,
+                  /*force_live_memory=*/false) == size) {
+            ObjectFile *objfile = module_sp->GetObjectFile();
+
+            stack.back().GetScalar() = DerefSizeExtractDataHelper(
+                addr_bytes, sizeof(addr_bytes), objfile->GetByteOrder(), size);
+            stack.back().ClearContext();
+            break;
+          } else {
+            if (error_ptr)
+              error_ptr->SetErrorStringWithFormat(
+                  "Failed to dereference pointer for for DW_OP_deref_size: "
+                  "%s\n",
+                  error.AsCString());
+            return false;
+          }
+        }
+        stack.back().GetScalar() = load_addr;
+        // Fall through to load address promotion code below.
+      }
+
+        LLVM_FALLTHROUGH;
       case Value::ValueType::Scalar:
       case Value::ValueType::LoadAddress:
         if (exe_ctx) {
           if (process) {
             lldb::addr_t pointer_addr =
                 stack.back().GetScalar().ULongLong(LLDB_INVALID_ADDRESS);
             uint8_t addr_bytes[sizeof(lldb::addr_t)];
             Status error;
             if (process->ReadMemory(pointer_addr, &addr_bytes, size, error) ==
                 size) {
-              DataExtractor addr_data(addr_bytes, sizeof(addr_bytes),
-                                      process->GetByteOrder(), size);
-              lldb::offset_t addr_data_offset = 0;
-              switch (size) {
-              case 1:
-                stack.back().GetScalar() = addr_data.GetU8(&addr_data_offset);
-                break;
-              case 2:
-                stack.back().GetScalar() = addr_data.GetU16(&addr_data_offset);
-                break;
-              case 4:
-                stack.back().GetScalar() = addr_data.GetU32(&addr_data_offset);
-                break;
-              case 8:
-                stack.back().GetScalar() = addr_data.GetU64(&addr_data_offset);
-                break;
-              default:
-                stack.back().GetScalar() =
-                    addr_data.GetAddress(&addr_data_offset);
-              }
+
+                  DerefSizeExtractDataHelper(addr_bytes, sizeof(addr_bytes),
+                                             process->GetByteOrder(), size);
               stack.back().ClearContext();
             } else {
               if (error_ptr)
                 error_ptr->SetErrorStringWithFormat(
                     "Failed to dereference pointer from 0x%" PRIx64
                     " for DW_OP_deref: %s\n",
                     pointer_addr, error.AsCString());
               return false;
             }
           } else {
             if (error_ptr)
               error_ptr->SetErrorString("NULL process for DW_OP_deref_size.\n");
             return false;
           }
         } else {
           if (error_ptr)
             error_ptr->SetErrorString(
                 "NULL execution context for DW_OP_deref_size.\n");
           return false;
         }
         break;
 
-      case Value::ValueType::FileAddress:
       case Value::ValueType::Invalid:
         if (error_ptr)
           error_ptr->SetErrorString("Invalid value for DW_OP_deref_size.\n");
         return false;
       }
 
     } break;
 
     // OPCODE: DW_OP_xderef_size

lldb/test/Shell/SymbolFile/DWARF/x86/DW_OP_deref_size_static_var.s

+# RUN: llvm-mc -filetype=obj -o %t -triple x86_64-apple-macosx10.15.0 %s
+# RUN: %lldb %t -o "target variable ug" -b | FileCheck %s
+
+# CHECK: (lldb) target variable ug
+# CHECK: (U) ug = {
+# CHECK:   raw = 0
+# CHECK:    = (a = 0, b = 0, c = 0, d = 0, e = 0, f = 0)
+# CHECK: }
+
+# We are testing how DWARFExpression::Evaluate(...) in the case of
+# DW_OP_deref_size deals with static variable.
+#
+# The address will be a ValueType::FileAddress type which we will not be able
+# to turn into a load address but it is a section offset. We should be able to
+# use Target::ReadMemory(...) to read the data in this case.
+# Compiling at -O1 allows us to capture this case and test it.
+#
+# typedef union {
+#   unsigned raw;
+#   struct {
+#      unsigned a : 8;
+#      unsigned b : 8;
+#      unsigned c : 6;
+#      unsigned d : 2;
+#      unsigned e : 6;
+#      unsigned f : 2;
+#   };
+# } U;
+#
+# // This appears first in the debug info and pulls the type definition in...
+# static U __attribute__((used)) _type_anchor;
+# // ... then our useful variable appears last in the debug info and we can
+# // tweak the assembly without needing to edit a lot of offsets by hand.
+# static U ug;
+#
+# extern void f(U);
+#
+# // Omit debug info for main.
+# __attribute__((nodebug))
+# int main() {
+#   ug.raw = 0x64A40101;
+#   f(ug);
+#   f((U)ug.raw);
+# }
+#
+# Compiled as follows:
+#
+#   clang -O1 -gdwarf-4 dw_op_deref_size_test.c -S -o dw_op_deref_size_test.s
+#
+# Hand modified .s file to remoce various section that are not needed for this
+# test
+
+.zerofill __DATA,__bss,_ug.0,1,2        ## @ug.0
+.zerofill __DATA,__bss,__type_anchor,4,2 ## @_type_anchor
+  .no_dead_strip  __type_anchor
+  .section  __DWARF,__debug_abbrev,regular,debug
+Lsection_abbrev:
+  .byte 1                               ## Abbreviation Code
+  .byte 17                              ## DW_TAG_compile_unit
+  .byte 1                               ## DW_CHILDREN_yes
+  .byte 37                              ## DW_AT_producer
+  .byte 14                              ## DW_FORM_strp
+  .byte 19                              ## DW_AT_language
+  .byte 5                               ## DW_FORM_data2
+  .byte 3                               ## DW_AT_name
+  .byte 14                              ## DW_FORM_strp
+  .ascii  "\202|"                         ## DW_AT_LLVM_sysroot
+  .byte 14                              ## DW_FORM_strp
+  .ascii  "\357\177"                      ## DW_AT_APPLE_sdk
+  .byte 14                              ## DW_FORM_strp
+  .byte 16                              ## DW_AT_stmt_list
+  .byte 23                              ## DW_FORM_sec_offset
+  .byte 27                              ## DW_AT_comp_dir
+  .byte 14                              ## DW_FORM_strp
+  .ascii  "\341\177"                      ## DW_AT_APPLE_optimized
+  .byte 25                              ## DW_FORM_flag_present
+  .byte 0                               ## EOM(1)
+  .byte 0                               ## EOM(2)
+  .byte 2                               ## Abbreviation Code
+  .byte 52                              ## DW_TAG_variable
+  .byte 0                               ## DW_CHILDREN_no
+  .byte 3                               ## DW_AT_name
+  .byte 14                              ## DW_FORM_strp
+  .byte 73                              ## DW_AT_type
+  .byte 19                              ## DW_FORM_ref4
+  .byte 58                              ## DW_AT_decl_file
+  .byte 11                              ## DW_FORM_data1
+  .byte 59                              ## DW_AT_decl_line
+  .byte 11                              ## DW_FORM_data1
+  .byte 2                               ## DW_AT_location
+  .byte 24                              ## DW_FORM_exprloc
+  .byte 0                               ## EOM(1)
+  .byte 0                               ## EOM(2)
+  .byte 3                               ## Abbreviation Code
+  .byte 22                              ## DW_TAG_typedef
+  .byte 0                               ## DW_CHILDREN_no
+  .byte 73                              ## DW_AT_type
+  .byte 19                              ## DW_FORM_ref4
+  .byte 3                               ## DW_AT_name
+  .byte 14                              ## DW_FORM_strp
+  .byte 58                              ## DW_AT_decl_file
+  .byte 11                              ## DW_FORM_data1
+  .byte 59                              ## DW_AT_decl_line
+  .byte 11                              ## DW_FORM_data1
+  .byte 0                               ## EOM(1)
+  .byte 0                               ## EOM(2)
+  .byte 4                               ## Abbreviation Code
+  .byte 23                              ## DW_TAG_union_type
+  .byte 1                               ## DW_CHILDREN_yes
+  .byte 11                              ## DW_AT_byte_size
+  .byte 11                              ## DW_FORM_data1
+  .byte 58                              ## DW_AT_decl_file
+  .byte 11                              ## DW_FORM_data1
+  .byte 59                              ## DW_AT_decl_line
+  .byte 11                              ## DW_FORM_data1
+  .byte 0                               ## EOM(1)
+  .byte 0                               ## EOM(2)
+  .byte 5                               ## Abbreviation Code
+  .byte 13                              ## DW_TAG_member
+  .byte 0                               ## DW_CHILDREN_no
+  .byte 3                               ## DW_AT_name
+  .byte 14                              ## DW_FORM_strp
+  .byte 73                              ## DW_AT_type
+  .byte 19                              ## DW_FORM_ref4
+  .byte 58                              ## DW_AT_decl_file
+  .byte 11                              ## DW_FORM_data1
+  .byte 59                              ## DW_AT_decl_line
+  .byte 11                              ## DW_FORM_data1
+  .byte 56                              ## DW_AT_data_member_location
+  .byte 11                              ## DW_FORM_data1
+  .byte 0                               ## EOM(1)
+  .byte 0                               ## EOM(2)
+  .byte 6                               ## Abbreviation Code
+  .byte 13                              ## DW_TAG_member
+  .byte 0                               ## DW_CHILDREN_no
+  .byte 73                              ## DW_AT_type
+  .byte 19                              ## DW_FORM_ref4
+  .byte 58                              ## DW_AT_decl_file
+  .byte 11                              ## DW_FORM_data1
+  .byte 59                              ## DW_AT_decl_line
+  .byte 11                              ## DW_FORM_data1
+  .byte 56                              ## DW_AT_data_member_location
+  .byte 11                              ## DW_FORM_data1
+  .byte 0                               ## EOM(1)
+  .byte 0                               ## EOM(2)
+  .byte 7                               ## Abbreviation Code
+  .byte 19                              ## DW_TAG_structure_type
+  .byte 1                               ## DW_CHILDREN_yes
+  .byte 11                              ## DW_AT_byte_size
+  .byte 11                              ## DW_FORM_data1
+  .byte 58                              ## DW_AT_decl_file
+  .byte 11                              ## DW_FORM_data1
+  .byte 59                              ## DW_AT_decl_line
+  .byte 11                              ## DW_FORM_data1
+  .byte 0                               ## EOM(1)
+  .byte 0                               ## EOM(2)
+  .byte 8                               ## Abbreviation Code
+  .byte 13                              ## DW_TAG_member
+  .byte 0                               ## DW_CHILDREN_no
+  .byte 3                               ## DW_AT_name
+  .byte 14                              ## DW_FORM_strp
+  .byte 73                              ## DW_AT_type
+  .byte 19                              ## DW_FORM_ref4
+  .byte 58                              ## DW_AT_decl_file
+  .byte 11                              ## DW_FORM_data1
+  .byte 59                              ## DW_AT_decl_line
+  .byte 11                              ## DW_FORM_data1
+  .byte 13                              ## DW_AT_bit_size
+  .byte 11                              ## DW_FORM_data1
+  .byte 107                             ## DW_AT_data_bit_offset
+  .byte 11                              ## DW_FORM_data1
+  .byte 0                               ## EOM(1)
+  .byte 0                               ## EOM(2)
+  .byte 9                               ## Abbreviation Code
+  .byte 36                              ## DW_TAG_base_type
+  .byte 0                               ## DW_CHILDREN_no
+  .byte 3                               ## DW_AT_name
+  .byte 14                              ## DW_FORM_strp
+  .byte 62                              ## DW_AT_encoding
+  .byte 11                              ## DW_FORM_data1
+  .byte 11                              ## DW_AT_byte_size
+  .byte 11                              ## DW_FORM_data1
+  .byte 0                               ## EOM(1)
+  .byte 0                               ## EOM(2)
+  .byte 0                               ## EOM(3)
+  .section  __DWARF,__debug_info,regular,debug
+Lsection_info:
+Lcu_begin0:
+.set Lset0, Ldebug_info_end0-Ldebug_info_start0 ## Length of Unit
+  .long Lset0
+Ldebug_info_start0:
+  .short  4                               ## DWARF version number
+.set Lset1, Lsection_abbrev-Lsection_abbrev ## Offset Into Abbrev. Section
+  .long Lset1
+  .byte 8                               ## Address Size (in bytes)
+  .byte 1                               ## Abbrev [1] 0xb:0xd0 DW_TAG_compile_unit
+  .long 0                               ## DW_AT_producer
+  .short  12                              ## DW_AT_language
+  .long 105                             ## DW_AT_name
+  .long 129                             ## DW_AT_LLVM_sysroot
+  .long 185                             ## DW_AT_APPLE_sdk
+  .long 0
+  .long 200                             ## DW_AT_comp_dir
+                                        ## DW_AT_APPLE_optimized
+  .byte 2                               ## Abbrev [2] 0x26:0x15 DW_TAG_variable
+  .long 219                             ## DW_AT_name
+  .long 59                              ## DW_AT_type
+  .byte 1                               ## DW_AT_decl_file
+  .byte 14                              ## DW_AT_decl_line
+  .byte 9                               ## DW_AT_location
+  .byte 3
+  .quad __type_anchor
+  .byte 3                               ## Abbrev [3] 0x3b:0xb DW_TAG_typedef
+  .long 70                              ## DW_AT_type
+  .long 232                             ## DW_AT_name
+  .byte 1                               ## DW_AT_decl_file
+  .byte 11                              ## DW_AT_decl_line
+  .byte 4                               ## Abbrev [4] 0x46:0x6c DW_TAG_union_type
+  .byte 4                               ## DW_AT_byte_size
+  .byte 1                               ## DW_AT_decl_file
+  .byte 1                               ## DW_AT_decl_line
+  .byte 5                               ## Abbrev [5] 0x4a:0xc DW_TAG_member
+  .long 234                             ## DW_AT_name
+  .long 178                             ## DW_AT_type
+  .byte 1                               ## DW_AT_decl_file
+  .byte 2                               ## DW_AT_decl_line
+  .byte 0                               ## DW_AT_data_member_location
+  .byte 6                               ## Abbrev [6] 0x56:0x8 DW_TAG_member
+  .long 94                              ## DW_AT_type
+  .byte 1                               ## DW_AT_decl_file
+  .byte 3                               ## DW_AT_decl_line
+  .byte 0                               ## DW_AT_data_member_location
+  .byte 7                               ## Abbrev [7] 0x5e:0x53 DW_TAG_structure_type
+  .byte 4                               ## DW_AT_byte_size
+  .byte 1                               ## DW_AT_decl_file
+  .byte 3                               ## DW_AT_decl_line
+  .byte 8                               ## Abbrev [8] 0x62:0xd DW_TAG_member
+  .long 251                             ## DW_AT_name
+  .long 178                             ## DW_AT_type
+  .byte 1                               ## DW_AT_decl_file
+  .byte 4                               ## DW_AT_decl_line
+  .byte 8                               ## DW_AT_bit_size
+  .byte 0                               ## DW_AT_data_bit_offset
+  .byte 8                               ## Abbrev [8] 0x6f:0xd DW_TAG_member
+  .long 253                             ## DW_AT_name
+  .long 178                             ## DW_AT_type
+  .byte 1                               ## DW_AT_decl_file
+  .byte 5                               ## DW_AT_decl_line
+  .byte 8                               ## DW_AT_bit_size
+  .byte 8                               ## DW_AT_data_bit_offset
+  .byte 8                               ## Abbrev [8] 0x7c:0xd DW_TAG_member
+  .long 255                             ## DW_AT_name
+  .long 178                             ## DW_AT_type
+  .byte 1                               ## DW_AT_decl_file
+  .byte 6                               ## DW_AT_decl_line
+  .byte 6                               ## DW_AT_bit_size
+  .byte 16                              ## DW_AT_data_bit_offset
+  .byte 8                               ## Abbrev [8] 0x89:0xd DW_TAG_member
+  .long 257                             ## DW_AT_name
+  .long 178                             ## DW_AT_type
+  .byte 1                               ## DW_AT_decl_file
+  .byte 7                               ## DW_AT_decl_line
+  .byte 2                               ## DW_AT_bit_size
+  .byte 22                              ## DW_AT_data_bit_offset
+  .byte 8                               ## Abbrev [8] 0x96:0xd DW_TAG_member
+  .long 259                             ## DW_AT_name
+  .long 178                             ## DW_AT_type
+  .byte 1                               ## DW_AT_decl_file
+  .byte 8                               ## DW_AT_decl_line
+  .byte 6                               ## DW_AT_bit_size
+  .byte 24                              ## DW_AT_data_bit_offset
+  .byte 8                               ## Abbrev [8] 0xa3:0xd DW_TAG_member
+  .long 261                             ## DW_AT_name
+  .long 178                             ## DW_AT_type
+  .byte 1                               ## DW_AT_decl_file
+  .byte 9                               ## DW_AT_decl_line
+  .byte 2                               ## DW_AT_bit_size
+  .byte 30                              ## DW_AT_data_bit_offset
+  .byte 0                               ## End Of Children Mark
+  .byte 0                               ## End Of Children Mark
+  .byte 9                               ## Abbrev [9] 0xb2:0x7 DW_TAG_base_type
+  .long 238                             ## DW_AT_name
+  .byte 7                               ## DW_AT_encoding
+  .byte 4                               ## DW_AT_byte_size
+  .byte 2                               ## Abbrev [2] 0xb9:0x21 DW_TAG_variable
+  .long 263                             ## DW_AT_name
+  .long 59                              ## DW_AT_type
+  .byte 1                               ## DW_AT_decl_file
+  .byte 17                              ## DW_AT_decl_line
+  .byte 21                              ## DW_AT_location
+  .byte 3
+  .quad _ug.0
+  .byte 148
+  .byte 1
+  .byte 16
+  .ascii  "\201\202\220\245\006"
+  .byte 30
+  .byte 48
+  .byte 34
+  .byte 159
+  .byte 0                               ## End Of Children Mark
+Ldebug_info_end0:
+  .section  __DWARF,__debug_str,regular,debug
+Linfo_string:
+  .zero 219
+  .asciz  "_type_anchor"                  ## string offset=219
+  .asciz  "U"                             ## string offset=232
+  .asciz  "raw"                           ## string offset=234
+  .asciz  "unsigned int"                  ## string offset=238
+  .asciz  "a"                             ## string offset=251
+  .asciz  "b"                             ## string offset=253
+  .asciz  "c"                             ## string offset=255
+  .asciz  "d"                             ## string offset=257
+  .asciz  "e"                             ## string offset=259
+  .asciz  "f"                             ## string offset=261
+  .asciz  "ug"                            ## string offset=263