Revert "Refactor rangelist handling to prepare for dwarf5 .debug_rngslist"HEADmaster

This reverts commit 2b936b06c12657b684f6c7276d6ae5a24cb48ab5.

After getting deep into the dwarf5 range reader, I realized that this
should be done a somewhat different way. So reverting in favor or
a better design, coming in a few minutes.

Change-Id: Ie0b2846e70b3df1e637831e96ea69fe093f4e712
Reviewed-on: https://chromium-review.googlesource.com/c/breakpad/breakpad/+/2446011
Reviewed-by: Mark Mentovai <mark@chromium.org>

6 files changed, 48 insertions, 59 deletions

diff --git a/src/common/dwarf/dwarf2reader.cc b/src/common/dwarf/dwarf2reader.cc
index ab31a980..aca83677 100644
--- a/src/common/dwarf/dwarf2reader.cc
+++ b/src/common/dwarf/dwarf2reader.cc
@@ -1569,11 +1569,10 @@ void LineInfo::ReadLines() {
 }
 
 RangeListReader::RangeListReader(const uint8_t* buffer, uint64_t size,
-                                 ByteReader* reader)
-    : buffer_(buffer), size_(size), reader_(reader) { }
+                                 ByteReader* reader, RangeListHandler* handler)
+    : buffer_(buffer), size_(size), reader_(reader), handler_(handler) { }
 
-bool RangeListReader::ReadRangeList(uint64_t offset,
-                                    RangeListHandler* handler) {
+bool RangeListReader::ReadRangeList(uint64_t offset) {
   const uint64_t max_address =
     (reader_->AddressSize() == 4) ? 0xffffffffUL
                                   : 0xffffffffffffffffULL;
@@ -1590,12 +1589,12 @@ bool RangeListReader::ReadRangeList(uint64_t offset,
       reader_->ReadAddress(buffer_ + offset + reader_->AddressSize());
 
     if (start_address == max_address) { // Base address selection
-      handler->SetBaseAddress(end_address);
+      handler_->SetBaseAddress(end_address);
     } else if (start_address == 0 && end_address == 0) { // End-of-list
-      handler->Finish();
+      handler_->Finish();
       list_end = true;
     } else { // Add a range entry
-      handler->AddRange(start_address, end_address);
+      handler_->AddRange(start_address, end_address);
     }
 
     offset += entry_size;
diff --git a/src/common/dwarf/dwarf2reader.h b/src/common/dwarf/dwarf2reader.h
index aa9e270d..e405e3a7 100644
--- a/src/common/dwarf/dwarf2reader.h
+++ b/src/common/dwarf/dwarf2reader.h
@@ -243,14 +243,16 @@ class RangeListHandler {
 
 class RangeListReader {
  public:
-  RangeListReader(const uint8_t* buffer, uint64_t size, ByteReader* reader);
+  RangeListReader(const uint8_t* buffer, uint64_t size, ByteReader* reader,
+                  RangeListHandler* handler);
 
-  bool ReadRangeList(uint64_t offset, RangeListHandler* handler);
+  bool ReadRangeList(uint64_t offset);
 
  private:
   const uint8_t* buffer_;
   uint64_t size_;
   ByteReader* reader_;
+  RangeListHandler* handler_;
 };
 
 // This class is the main interface between the reader and the
diff --git a/src/common/dwarf_cu_to_module.cc b/src/common/dwarf_cu_to_module.cc
index 589f8bb2..a5bc7d6c 100644
--- a/src/common/dwarf_cu_to_module.cc
+++ b/src/common/dwarf_cu_to_module.cc
@@ -134,7 +134,6 @@ DwarfCUToModule::FileContext::FileContext(const string& filename,
     : filename_(filename),
       module_(module),
       handle_inter_cu_refs_(handle_inter_cu_refs),
-      range_list_reader_(nullptr, 0, nullptr),
       file_private_(new FilePrivate()) {
 }
 
@@ -194,7 +193,7 @@ struct DwarfCUToModule::CUContext {
   // For printing error messages.
   WarningReporter* reporter;
 
-  // For handling ranges, however they may be specified.
+  // For reading ranges from the .debug_ranges section
   RangesHandler* ranges_handler;
 
   // The source language of this compilation unit.
@@ -207,9 +206,6 @@ struct DwarfCUToModule::CUContext {
   uint64_t high_pc;
   uint64_t ranges;
 
-  // For reading dwarf4 ranges.
-  scoped_ptr<dwarf2reader::RangeListReader> range_list_reader_;
-
   // The functions defined in this compilation unit. We accumulate
   // them here during parsing. Then, in DwarfCUToModule::Finish, we
   // assign them lines and add them to file_context->module.
@@ -516,15 +512,6 @@ void DwarfCUToModule::FuncHandler::ProcessAttributeUnsigned(
       break;
     case dwarf2reader::DW_AT_ranges:
       ranges_ = data;
-      if (cu_context_->ranges_handler) {
-          cu_context_->ranges_handler->SetRangesReader(
-              &cu_context_->file_context->range_list_reader_);
-      } else {
-        cu_context_->reporter->MissingRanges();
-        // The rest of the code will fall back to low-pc, which is better than
-        // nothing.
-        ranges_ = 0;
-      }
       break;
 
     default:
diff --git a/src/common/dwarf_cu_to_module.h b/src/common/dwarf_cu_to_module.h
index e71c3e77..3e15b667 100644
--- a/src/common/dwarf_cu_to_module.h
+++ b/src/common/dwarf_cu_to_module.h
@@ -89,11 +89,6 @@ class DwarfCUToModule: public dwarf2reader::RootDIEHandler {
                                 const uint8_t* contents,
                                 uint64_t length);
 
-    void SetDebugRangeInfo(const uint8_t* contents, uint64_t size,
-                           dwarf2reader::ByteReader* reader) {
-      range_list_reader_ = dwarf2reader::RangeListReader(contents, size, reader);
-    }
-
     // Clear the section map for testing.
     void ClearSectionMapForTest();
 
@@ -124,9 +119,6 @@ class DwarfCUToModule: public dwarf2reader::RootDIEHandler {
     // True if we are handling references between compilation units.
     const bool handle_inter_cu_refs_;
 
-    // Reader for .debug_ranges section, which is global to the file.
-    dwarf2reader::RangeListReader range_list_reader_;
-
     // Inter-compilation unit data used internally by the handlers.
     scoped_ptr<FilePrivate> file_private_;
   };
@@ -135,23 +127,16 @@ class DwarfCUToModule: public dwarf2reader::RootDIEHandler {
   // DwarfCUToModule.
   class RangesHandler {
    public:
-    RangesHandler() : reader_(nullptr) { }
+    RangesHandler() { }
     virtual ~RangesHandler() { }
 
     // Called when finishing a function to populate the function's ranges.
-    // base_address holds the base PC the range list values are offsets
-    // off. Return false if the rangelist falls out of the relevant section.
+    // The ranges' entries are read starting from offset in the .debug_ranges
+    // section, base_address holds the base PC the range list values are
+    // offsets off. Return false if the rangelist falls out of the
+    // .debug_ranges section.
     virtual bool ReadRanges(uint64_t offset, Module::Address base_address,
                             vector<Module::Range>* ranges) = 0;
-
-    // Read ranges from this buffer and interpret them according to attr. Called
-    // upon seeing a DW_AT_ranges or DW_AT_rngslist attribute.
-    void SetRangesReader(dwarf2reader::RangeListReader* reader) {
-      reader_ = reader;
-    }
-
-   protected:
-    dwarf2reader::RangeListReader* reader_;
   };
 
   // An abstract base class for handlers that handle DWARF line data
diff --git a/src/common/linux/dump_symbols.cc b/src/common/linux/dump_symbols.cc
index ac2559cd..8ecf0bc4 100644
--- a/src/common/linux/dump_symbols.cc
+++ b/src/common/linux/dump_symbols.cc
@@ -232,14 +232,23 @@ bool LoadStabs(const typename ElfClass::Ehdr* elf_header,
 // owned by a function) with the results.
 class DumperRangesHandler : public DwarfCUToModule::RangesHandler {
  public:
-  DumperRangesHandler() { }
+  DumperRangesHandler(const uint8_t* buffer, uint64_t size,
+                      dwarf2reader::ByteReader* reader)
+      : buffer_(buffer), size_(size), reader_(reader) { }
 
   bool ReadRanges(uint64_t offset, Module::Address base_address,
                   vector<Module::Range>* ranges) {
     DwarfRangeListHandler handler(base_address, ranges);
+    dwarf2reader::RangeListReader rangelist_reader(buffer_, size_, reader_,
+                                                   &handler);
 
-    return reader_->ReadRangeList(offset, &handler);
+    return rangelist_reader.ReadRangeList(offset);
   }
+
+ private:
+  const uint8_t* buffer_;
+  uint64_t size_;
+  dwarf2reader::ByteReader* reader_;
 };
 
 // A line-to-module loader that accepts line number info parsed by
@@ -305,18 +314,17 @@ bool LoadDwarf(const string& dwarf_filename,
   }
 
   // Optional .debug_ranges reader
+  scoped_ptr<DumperRangesHandler> ranges_handler;
   dwarf2reader::SectionMap::const_iterator ranges_entry =
       file_context.section_map().find(".debug_ranges");
   if (ranges_entry != file_context.section_map().end()) {
     const std::pair<const uint8_t*, uint64_t>& ranges_section =
       ranges_entry->second;
-    file_context.SetDebugRangeInfo(ranges_section.first,
-                                   ranges_section.second,
-                                   &byte_reader);
+    ranges_handler.reset(
+      new DumperRangesHandler(ranges_section.first, ranges_section.second,
+                              &byte_reader));
   }
 
-  DumperRangesHandler ranges_handler;
-
   // Parse all the compilation units in the .debug_info section.
   DumperLineToModule line_to_module(&byte_reader);
   dwarf2reader::SectionMap::const_iterator debug_info_entry =
@@ -333,7 +341,7 @@ bool LoadDwarf(const string& dwarf_filename,
     // data that was found.
     DwarfCUToModule::WarningReporter reporter(dwarf_filename, offset);
     DwarfCUToModule root_handler(&file_context, &line_to_module,
-                                 &ranges_handler, &reporter);
+                                 ranges_handler.get(), &reporter);
     // Make a Dwarf2Handler that drives the DIEHandler.
     dwarf2reader::DIEDispatcher die_dispatcher(&root_handler);
     // Make a DWARF parser for the compilation unit at OFFSET.
diff --git a/src/common/mac/dump_syms.cc b/src/common/mac/dump_syms.cc
index 9ee6e006..24bcd653 100644
--- a/src/common/mac/dump_syms.cc
+++ b/src/common/mac/dump_syms.cc
@@ -311,14 +311,23 @@ string DumpSymbols::Identifier() {
 class DumpSymbols::DumperRangesHandler:
       public DwarfCUToModule::RangesHandler {
  public:
-  DumperRangesHandler() { }
+  DumperRangesHandler(const uint8_t* buffer, uint64_t size,
+                      dwarf2reader::ByteReader* reader)
+      : buffer_(buffer), size_(size), reader_(reader) { }
 
   bool ReadRanges(uint64_t offset, Module::Address base_address,
                   vector<Module::Range>* ranges) {
     DwarfRangeListHandler handler(base_address, ranges);
+    dwarf2reader::RangeListReader rangelist_reader(buffer_, size_, reader_,
+                                                   &handler);
 
-    return reader_->ReadRangeList(offset, &handler);
+    return rangelist_reader.ReadRangeList(offset);
   }
+
+ private:
+  const uint8_t* buffer_;
+  uint64_t size_;
+  dwarf2reader::ByteReader* reader_;
 };
 
 // A line-to-module loader that accepts line number info parsed by
@@ -448,18 +457,17 @@ void DumpSymbols::ReadDwarf(google_breakpad::Module* module,
   DumperLineToModule line_to_module(&byte_reader);
 
   // Optional .debug_ranges reader
+  scoped_ptr<DumperRangesHandler> ranges_handler;
   dwarf2reader::SectionMap::const_iterator ranges_entry =
       file_context.section_map().find("__debug_ranges");
   if (ranges_entry != file_context.section_map().end()) {
     const std::pair<const uint8_t*, uint64_t>& ranges_section =
       ranges_entry->second;
-    file_context.SetDebugRangeInfo(ranges_section.first,
-                                   ranges_section.second,
-                                   &byte_reader);
+    ranges_handler.reset(
+      new DumperRangesHandler(ranges_section.first, ranges_section.second,
+                              &byte_reader));
   }
 
-  DumperRangesHandler ranges_handler;
-
   // Walk the __debug_info section, one compilation unit at a time.
   uint64_t debug_info_length = debug_info_section.second;
   for (uint64_t offset = 0; offset < debug_info_length;) {
@@ -468,7 +476,7 @@ void DumpSymbols::ReadDwarf(google_breakpad::Module* module,
     DwarfCUToModule::WarningReporter reporter(selected_object_name_,
                                               offset);
     DwarfCUToModule root_handler(&file_context, &line_to_module,
-                                 &ranges_handler, &reporter);
+                                 ranges_handler.get(), &reporter);
     // Make a Dwarf2Handler that drives our DIEHandler.
     dwarf2reader::DIEDispatcher die_dispatcher(&root_handler);
     // Make a DWARF parser for the compilation unit at OFFSET.