Fix reading DW_AT_ranges in split dwarf.

Bug: b/280290608, chromium:1448979
Change-Id: I3f9e4c3d62b4c858238ccbbda0366926c306e27f
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/4568824
Reviewed-by: Joshua Peraza <jperaza@chromium.org>

src/common/dwarf/dwarf2enums.h

@@ -580,10 +580,10 @@ enum DwarfSectionId {
   DW_SECT_TYPES = 2,
   DW_SECT_ABBREV = 3,
   DW_SECT_LINE = 4,
-  DW_SECT_LOC = 5,
+  DW_SECT_LOCLISTS = 5,
   DW_SECT_STR_OFFSETS = 6,
-  DW_SECT_MACINFO = 7,
+  DW_SECT_MACRO = 7,
-  DW_SECT_MACRO = 8
+  DW_SECT_RNGLISTS = 8
 };
 
 // Source languages.  These are values for DW_AT_language.

src/common/dwarf/dwarf2reader.cc

@@ -80,7 +80,7 @@ CompilationUnit::CompilationUnit(const string& path,
       str_offsets_buffer_(NULL), str_offsets_buffer_length_(0),
       addr_buffer_(NULL), addr_buffer_length_(0),
       is_split_dwarf_(false), is_type_unit_(false), dwo_id_(0), dwo_name_(),
-      skeleton_dwo_id_(0), ranges_base_(0), addr_base_(0),
+      skeleton_dwo_id_(0), addr_base_(0),
       str_offsets_base_(0), have_checked_for_dwp_(false),
       should_process_split_dwarf_(false) {}
 
@@ -91,16 +91,11 @@ CompilationUnit::CompilationUnit(const string& path,
 // the executable file, and call it as if we were still
 // processing the original compilation unit.
 
-void CompilationUnit::SetSplitDwarf(const uint8_t* addr_buffer,
+void CompilationUnit::SetSplitDwarf(
-                                    uint64_t addr_buffer_length,
                                     uint64_t addr_base,
-                                    uint64_t ranges_base,
                                     uint64_t dwo_id) {
   is_split_dwarf_ = true;
-  addr_buffer_ = addr_buffer;
-  addr_buffer_length_ = addr_buffer_length;
   addr_base_ = addr_base;
-  ranges_base_ = ranges_base;
   skeleton_dwo_id_ = dwo_id;
 }
 
@@ -889,7 +884,9 @@ const uint8_t* CompilationUnit::ProcessDIE(uint64_t dieoffset,
   // DW_AT_str_offsets_base or DW_AT_addr_base.  If it does, that attribute must
   // be found and processed before trying to process the other attributes;
   // otherwise the string or address values will all come out incorrect.
-  if (abbrev.tag == DW_TAG_compile_unit && header_.version == 5) {
+  if ((abbrev.tag == DW_TAG_compile_unit ||
+       abbrev.tag == DW_TAG_skeleton_unit) &&
+      header_.version == 5) {
     uint64_t dieoffset_copy = dieoffset;
     const uint8_t* start_copy = start;
     for (AttributeList::const_iterator i = abbrev.attributes.begin();
@@ -1016,7 +1013,8 @@ bool CompilationUnit::ProcessSplitDwarf(std::string& split_file,
       string debug_suffix(".debug");
       dwp_path = path_;
       size_t found = path_.rfind(debug_suffix);
-      if (found + debug_suffix.length() == path_.length())
+      if (found != string::npos &&
+          found + debug_suffix.length() == path_.length())
         dwp_path = dwp_path.replace(found, debug_suffix.length(), dwp_suffix);
     }
     if (stat(dwp_path.c_str(), &statbuf) == 0) {
@@ -1133,6 +1131,8 @@ void DwpReader::Initialize() {
     info_data_ = elf_reader_->GetSectionByName(".debug_info.dwo", &info_size_);
     str_offsets_data_ = elf_reader_->GetSectionByName(".debug_str_offsets.dwo",
                                                       &str_offsets_size_);
+    rnglist_data_ =
+        elf_reader_->GetSectionByName(".debug_rnglists.dwo", &rnglist_size_);
     if (size_table_ >= cu_index_ + cu_index_size_) {
       version_ = 0;
     }
@@ -1245,6 +1245,12 @@ void DwpReader::ReadDebugSectionsForCU(uint64_t dwo_id,
             ".debug_str_offsets",
             std::make_pair(reinterpret_cast<const uint8_t*> (str_offsets_data_)
                            + offset, size)));
+      } else if (section_id == DW_SECT_RNGLISTS) {
+        sections->insert(std::make_pair(
+            ".debug_rnglists",
+            std::make_pair(
+                reinterpret_cast<const uint8_t*>(rnglist_data_) + offset,
+                size)));
       }
     }
     sections->insert(std::make_pair(
@@ -1830,6 +1836,11 @@ bool RangeListReader::ReadRanges(enum DwarfForm form, uint64_t data) {
       return ReadDebugRngList(data);
     }
   } else if (form == DW_FORM_rnglistx) {
+    if (cu_info_->ranges_base_ == 0) {
+      // In split dwarf, there's no DW_AT_rnglists_base attribute, range_base
+      // will just be the first byte after the header.
+      cu_info_->ranges_base_ = reader_->OffsetSize() == 4? 12: 20;
+    }
     offset_array_ = cu_info_->ranges_base_;
     uint64_t index_offset = reader_->OffsetSize() * data;
     uint64_t range_list_offset =

src/common/dwarf/dwarf2reader.h

@@ -469,8 +469,7 @@ class CompilationUnit {
   // compilation unit.  We also inherit the Dwarf2Handler from
   // the executable file, and call it as if we were still
   // processing the original compilation unit.
-  void SetSplitDwarf(const uint8_t* addr_buffer, uint64_t addr_buffer_length,
+  void SetSplitDwarf(uint64_t addr_base, uint64_t dwo_id);
-                     uint64_t addr_base, uint64_t ranges_base, uint64_t dwo_id);
 
   // Begin reading a Dwarf2 compilation unit, and calling the
   // callbacks in the Dwarf2Handler
@@ -493,7 +492,7 @@ class CompilationUnit {
 
   uint64_t GetAddrBase() { return addr_base_; }
 
-  uint64_t GetRangeBase() { return ranges_base_; }
+  uint64_t GetLowPC() { return low_pc_; }
 
   uint64_t GetDWOID() { return dwo_id_; }
 
@@ -583,14 +582,8 @@ class CompilationUnit {
     else if (attr == DW_AT_str_offsets_base) {
       str_offsets_base_ = data;
     }
-    else if (attr == DW_AT_GNU_ranges_base || attr == DW_AT_rnglists_base) {
+    else if (attr == DW_AT_low_pc) {
-      ranges_base_ = data;
+      low_pc_ = data;
-    }
-    // TODO(yunlian): When we add DW_AT_ranges_base from DWARF-5,
-    // that base will apply to DW_AT_ranges attributes in the
-    // skeleton CU as well as in the .dwo/.dwp files.
-    else if (attr == DW_AT_ranges && is_split_dwarf_) {
-      data += ranges_base_;
     }
     handler_->ProcessAttributeUnsigned(offset, attr, form, data);
   }
@@ -745,10 +738,6 @@ class CompilationUnit {
   // from the skeleton CU.
   uint64_t skeleton_dwo_id_;
 
-  // The value of the DW_AT_GNU_ranges_base or DW_AT_rnglists_base attribute,
-  // if any.
-  uint64_t ranges_base_;
-
   // The value of the DW_AT_GNU_addr_base attribute, if any.
   uint64_t addr_base_;
 
@@ -765,6 +754,9 @@ class CompilationUnit {
   std::unique_ptr<DwpReader> dwp_reader_;
 
   bool should_process_split_dwarf_;
+
+  // The value of the DW_AT_low_pc attribute, if any.
+  uint64_t low_pc_;
 };
 
 // A Reader for a .dwp file.  Supports the fetching of DWARF debug
@@ -851,6 +843,8 @@ class DwpReader {
   size_t info_size_;
   const char* str_offsets_data_;
   size_t str_offsets_size_;
+  const char* rnglist_data_;
+  size_t rnglist_size_;
 };
 
 // This class is a reader for DWARF's Call Frame Information.  CFI

src/common/dwarf_cu_to_module.cc

@@ -169,19 +169,23 @@ bool DwarfCUToModule::FileContext::IsUnhandledInterCUReference(
 // parsing. This is for data shared across the CU's entire DIE tree,
 // and parameters from the code invoking the CU parser.
 struct DwarfCUToModule::CUContext {
-  CUContext(FileContext* file_context_arg, WarningReporter* reporter_arg,
+  CUContext(FileContext* file_context_arg,
-            RangesHandler* ranges_handler_arg)
+            WarningReporter* reporter_arg,
+            RangesHandler* ranges_handler_arg,
+            uint64_t low_pc,
+            uint64_t addr_base)
       : version(0),
         file_context(file_context_arg),
         reporter(reporter_arg),
         ranges_handler(ranges_handler_arg),
         language(Language::CPlusPlus),
-        low_pc(0),
+        low_pc(low_pc),
         high_pc(0),
         ranges_form(DW_FORM_sec_offset),
         ranges_data(0),
         ranges_base(0),
-        str_offsets_base(0) { }
+        addr_base(addr_base),
+        str_offsets_base(0) {}
 
   ~CUContext() {
     for (vector<Module::Function*>::iterator it = functions.begin();
@@ -854,7 +858,7 @@ void DwarfCUToModule::FuncHandler::Finish() {
       iter->second->name = name_;
   }
 
-  if (!ranges_data_) {
+  if (low_pc_ && high_pc_) {
     // Make high_pc_ an address, if it isn't already.
     if (high_pc_form_ != DW_FORM_addr &&
         high_pc_form_ != DW_FORM_GNU_addr_index &&
@@ -868,7 +872,7 @@ void DwarfCUToModule::FuncHandler::Finish() {
 
     Module::Range range(low_pc_, high_pc_ - low_pc_);
     ranges.push_back(range);
-  } else {
+  } else if (ranges_data_) {
     RangesHandler* ranges_handler = cu_context_->ranges_handler;
     if (ranges_handler) {
       RangeListReader::CURangesInfo cu_info;
@@ -1069,10 +1073,16 @@ DwarfCUToModule::DwarfCUToModule(FileContext* file_context,
                                  LineToModuleHandler* line_reader,
                                  RangesHandler* ranges_handler,
                                  WarningReporter* reporter,
-                                 bool handle_inline)
+                                 bool handle_inline,
+                                 uint64_t low_pc,
+                                 uint64_t addr_base)
     : RootDIEHandler(handle_inline),
       line_reader_(line_reader),
-      cu_context_(new CUContext(file_context, reporter, ranges_handler)),
+      cu_context_(new CUContext(file_context,
+                                reporter,
+                                ranges_handler,
+                                low_pc,
+                                addr_base)),
       child_context_(new DIEContext()),
       has_source_line_info_(false) {}
 

src/common/dwarf_cu_to_module.h

@@ -264,7 +264,9 @@ class DwarfCUToModule: public RootDIEHandler {
                   LineToModuleHandler* line_reader,
                   RangesHandler* ranges_handler,
                   WarningReporter* reporter,
-                  bool handle_inline = false);
+                  bool handle_inline = false,
+                  uint64_t low_pc = 0,
+                  uint64_t addr_base = 0);
   ~DwarfCUToModule();
 
   void ProcessAttributeSigned(enum DwarfAttribute attr,

src/common/linux/dump_symbols.cc

@@ -348,18 +348,27 @@ void StartProcessSplitDwarf(google_breakpad::CompilationUnit* reader,
     return;
   DwarfCUToModule::FileContext file_context(split_file, module,
                                             handle_inter_cu_refs);
+  for (auto section : split_sections)
+    file_context.AddSectionToSectionMap(section.first, section.second.first,
+                                        section.second.second);
+  // Because DWP/DWO file doesn't have .debug_addr/.debug_line, its debug info
+  // will refer to .debug_addr/.debug_line in the main binary.
+  if (file_context.section_map().find(".debug_addr") ==
+      file_context.section_map().end())
+    file_context.AddSectionToSectionMap(".debug_addr", reader->GetAddrBuffer(),
+                                        reader->GetAddrBufferLen());
+
   DumperRangesHandler ranges_handler(&split_byte_reader);
   DumperLineToModule line_to_module(&split_byte_reader);
   DwarfCUToModule::WarningReporter reporter(split_file, cu_offset);
   DwarfCUToModule root_handler(&file_context, &line_to_module, &ranges_handler,
-                               &reporter, handle_inline);
+                               &reporter, handle_inline, reader->GetLowPC(),
+                               reader->GetAddrBase());
   google_breakpad::DIEDispatcher die_dispatcher(&root_handler);
-  google_breakpad::CompilationUnit split_reader(split_file, split_sections,
+  google_breakpad::CompilationUnit split_reader(
-                                                cu_offset, &split_byte_reader,
+      split_file, file_context.section_map(), cu_offset, &split_byte_reader,
       &die_dispatcher);
-  split_reader.SetSplitDwarf(reader->GetAddrBuffer(),
+  split_reader.SetSplitDwarf(reader->GetAddrBase(), reader->GetDWOID());
-                             reader->GetAddrBufferLen(), reader->GetAddrBase(),
-                             reader->GetRangeBase(), reader->GetDWOID());
   split_reader.Start();
   // Normally, it won't happen unless we have transitive reference.
   if (split_reader.ShouldProcessSplitDwarf()) {

src/common/mac/dump_syms.cc

@@ -439,18 +439,26 @@ void DumpSymbols::StartProcessSplitDwarf(
     return;
   DwarfCUToModule::FileContext file_context(split_file, module,
                                             handle_inter_cu_refs);
+  for (auto section : split_sections)
+    file_context.AddSectionToSectionMap(section.first, section.second.first,
+                                        section.second.second);
+  // If DWP/DWO file doesn't have .debug_addr, its debug info will refer to
+  // .debug_addr in the main binary.
+  if (file_context.section_map().find(".debug_addr") ==
+      file_context.section_map().end())
+    file_context.AddSectionToSectionMap(".debug_addr", reader->GetAddrBuffer(),
+                                        reader->GetAddrBufferLen());
   DumperRangesHandler ranges_handler(&split_byte_reader);
   DumperLineToModule line_to_module(&split_byte_reader);
   DwarfCUToModule::WarningReporter reporter(split_file, cu_offset);
   DwarfCUToModule root_handler(&file_context, &line_to_module, &ranges_handler,
-                               &reporter, handle_inline);
+                               &reporter, handle_inline, reader->GetLowPC(),
+                               reader->GetAddrBase());
   google_breakpad::DIEDispatcher die_dispatcher(&root_handler);
-  google_breakpad::CompilationUnit split_reader(split_file, split_sections,
+  google_breakpad::CompilationUnit split_reader(
-                                                cu_offset, &split_byte_reader,
+      split_file, file_context.section_map(), cu_offset, &split_byte_reader,
       &die_dispatcher);
-  split_reader.SetSplitDwarf(reader->GetAddrBuffer(),
+  split_reader.SetSplitDwarf(reader->GetAddrBase(), reader->GetDWOID());
-                             reader->GetAddrBufferLen(), reader->GetAddrBase(),
-                             reader->GetRangeBase(), reader->GetDWOID());
   split_reader.Start();
   // Normally, it won't happen unless we have transitive reference.
   if (split_reader.ShouldProcessSplitDwarf()) {