xref: /aosp_15_r20/external/google-breakpad/src/common/dwarf_cu_to_module.h (revision 9712c20fc9bbfbac4935993a2ca0b3958c5adad2)
1 // -*- mode: c++ -*-
2 
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30 
31 // Original author: Jim Blandy <[email protected]> <[email protected]>
32 
33 // Add DWARF debugging information to a Breakpad symbol file. This
34 // file defines the DwarfCUToModule class, which accepts parsed DWARF
35 // data and populates a google_breakpad::Module with the results; the
36 // Module can then write its contents as a Breakpad symbol file.
37 
38 #ifndef COMMON_LINUX_DWARF_CU_TO_MODULE_H__
39 #define COMMON_LINUX_DWARF_CU_TO_MODULE_H__
40 
41 #include <stdint.h>
42 
43 #include <string>
44 #include <vector>
45 
46 #include "common/language.h"
47 #include "common/module.h"
48 #include "common/dwarf/dwarf2diehandler.h"
49 #include "common/dwarf/dwarf2reader.h"
50 #include "common/scoped_ptr.h"
51 #include "common/using_std_string.h"
52 
53 namespace google_breakpad {
54 
55 // Populate a google_breakpad::Module with DWARF debugging information.
56 //
57 // An instance of this class can be provided as a handler to a
58 // DIEDispatcher, which can in turn be a handler for a
59 // CompilationUnit DWARF parser. The handler uses the results
60 // of parsing to populate a google_breakpad::Module with source file,
61 // function, and source line information.
62 class DwarfCUToModule: public RootDIEHandler {
63   struct FilePrivate;
64  public:
65   // Information global to the DWARF-bearing file we are processing,
66   // for use by DwarfCUToModule. Each DwarfCUToModule instance deals
67   // with a single compilation unit within the file, but information
68   // global to the whole file is held here. The client is responsible
69   // for filling it in appropriately (except for the 'file_private'
70   // field, which the constructor and destructor take care of), and
71   // then providing it to the DwarfCUToModule instance for each
72   // compilation unit we process in that file. Set HANDLE_INTER_CU_REFS
73   // to true to handle debugging symbols with DW_FORM_ref_addr entries.
74   class FileContext {
75    public:
76     FileContext(const string& filename,
77                 Module* module,
78                 bool handle_inter_cu_refs);
79     ~FileContext();
80 
81     // Add CONTENTS of size LENGTH to the section map as NAME.
82     void AddSectionToSectionMap(const string& name,
83                                 const uint8_t* contents,
84                                 uint64_t length);
85 
86     void AddManagedSectionToSectionMap(const string& name,
87                                 uint8_t* contents,
88                                 uint64_t length);
89 
90     // Clear the section map for testing.
91     void ClearSectionMapForTest();
92 
93     const SectionMap& section_map() const;
94 
95    private:
96     friend class DwarfCUToModule;
97 
98     // Clears all the Specifications if HANDLE_INTER_CU_REFS_ is false.
99     void ClearSpecifications();
100 
101     // Given an OFFSET and a CU that starts at COMPILATION_UNIT_START, returns
102     // true if this is an inter-compilation unit reference that is not being
103     // handled.
104     bool IsUnhandledInterCUReference(uint64_t offset,
105                                      uint64_t compilation_unit_start) const;
106 
107     // The name of this file, for use in error messages.
108     const string filename_;
109 
110     // A map of this file's sections, used for finding other DWARF
111     // sections that the .debug_info section may refer to.
112     SectionMap section_map_;
113 
114     // The Module to which we're contributing definitions.
115     Module* module_;
116 
117     // True if we are handling references between compilation units.
118     const bool handle_inter_cu_refs_;
119 
120     // Inter-compilation unit data used internally by the handlers.
121     scoped_ptr<FilePrivate> file_private_;
122     std::vector<uint8_t *> uncompressed_sections_;
123   };
124 
125   // An abstract base class for handlers that handle DWARF range lists for
126   // DwarfCUToModule.
127   class RangesHandler {
128    public:
RangesHandler()129     RangesHandler() { }
~RangesHandler()130     virtual ~RangesHandler() { }
131 
132     // Called when finishing a function to populate the function's ranges.
133     // The entries are read according to the form and data.
134     virtual bool ReadRanges(
135         enum DwarfForm form, uint64_t data,
136         RangeListReader::CURangesInfo* cu_info,
137         vector<Module::Range>* ranges) = 0;
138   };
139 
140   // An abstract base class for handlers that handle DWARF line data
141   // for DwarfCUToModule. DwarfCUToModule could certainly just use
142   // LineInfo itself directly, but decoupling things
143   // this way makes unit testing a little easier.
144   class LineToModuleHandler {
145    public:
LineToModuleHandler()146     LineToModuleHandler() { }
~LineToModuleHandler()147     virtual ~LineToModuleHandler() { }
148 
149     // Called at the beginning of a new compilation unit, prior to calling
150     // ReadProgram(). compilation_dir will indicate the path that the
151     // current compilation unit was compiled in, consistent with the
152     // DW_AT_comp_dir DIE.
153     virtual void StartCompilationUnit(const string& compilation_dir) = 0;
154 
155     // Populate MODULE and LINES with source file names and code/line
156     // mappings, given a pointer to some DWARF line number data
157     // PROGRAM, and an overestimate of its size. Add no zero-length
158     // lines to LINES.
159     virtual void ReadProgram(const uint8_t* program, uint64_t length,
160                              const uint8_t* string_section,
161                              uint64_t string_section_length,
162                              const uint8_t* line_string_section,
163                              uint64_t line_string_length,
164                              Module* module, vector<Module::Line>* lines,
165                              map<uint32_t, Module::File*>* files) = 0;
166   };
167 
168   // The interface DwarfCUToModule uses to report warnings. The member
169   // function definitions for this class write messages to stderr, but
170   // you can override them if you'd like to detect or report these
171   // conditions yourself.
172   class WarningReporter {
173    public:
174     // Warn about problems in the DWARF file FILENAME, in the
175     // compilation unit at OFFSET.
WarningReporter(const string & filename,uint64_t cu_offset)176     WarningReporter(const string& filename, uint64_t cu_offset)
177         : filename_(filename), cu_offset_(cu_offset), printed_cu_header_(false),
178           printed_unpaired_header_(false),
179           uncovered_warnings_enabled_(false) { }
~WarningReporter()180     virtual ~WarningReporter() { }
181 
182     // Set the name of the compilation unit we're processing to NAME.
SetCUName(const string & name)183     virtual void SetCUName(const string& name) { cu_name_ = name; }
184 
185     // Accessor and setter for uncovered_warnings_enabled_.
186     // UncoveredFunction and UncoveredLine only report a problem if that is
187     // true. By default, these warnings are disabled, because those
188     // conditions occur occasionally in healthy code.
uncovered_warnings_enabled()189     virtual bool uncovered_warnings_enabled() const {
190       return uncovered_warnings_enabled_;
191     }
set_uncovered_warnings_enabled(bool value)192     virtual void set_uncovered_warnings_enabled(bool value) {
193       uncovered_warnings_enabled_ = value;
194     }
195 
196     // A DW_AT_specification in the DIE at OFFSET refers to a DIE we
197     // haven't processed yet, or that wasn't marked as a declaration,
198     // at TARGET.
199     virtual void UnknownSpecification(uint64_t offset, uint64_t target);
200 
201     // A DW_AT_abstract_origin in the DIE at OFFSET refers to a DIE we
202     // haven't processed yet, or that wasn't marked as inline, at TARGET.
203     virtual void UnknownAbstractOrigin(uint64_t offset, uint64_t target);
204 
205     // We were unable to find the DWARF section named SECTION_NAME.
206     virtual void MissingSection(const string& section_name);
207 
208     // The CU's DW_AT_stmt_list offset OFFSET is bogus.
209     virtual void BadLineInfoOffset(uint64_t offset);
210 
211     // FUNCTION includes code covered by no line number data.
212     virtual void UncoveredFunction(const Module::Function& function);
213 
214     // Line number NUMBER in LINE_FILE, of length LENGTH, includes code
215     // covered by no function.
216     virtual void UncoveredLine(const Module::Line& line);
217 
218     // The DW_TAG_subprogram DIE at OFFSET has no name specified directly
219     // in the DIE, nor via a DW_AT_specification or DW_AT_abstract_origin
220     // link.
221     virtual void UnnamedFunction(uint64_t offset);
222 
223     // __cxa_demangle() failed to demangle INPUT.
224     virtual void DemangleError(const string& input);
225 
226     // The DW_FORM_ref_addr at OFFSET to TARGET was not handled because
227     // FilePrivate did not retain the inter-CU specification data.
228     virtual void UnhandledInterCUReference(uint64_t offset, uint64_t target);
229 
230     // The DW_AT_ranges at offset is malformed (truncated or outside of the
231     // .debug_ranges section's bound).
232     virtual void MalformedRangeList(uint64_t offset);
233 
234     // A DW_AT_ranges attribute was encountered but the no .debug_ranges
235     // section was found.
236     virtual void MissingRanges();
237 
cu_offset()238     uint64_t cu_offset() const {
239       return cu_offset_;
240     }
241 
242    protected:
243     const string filename_;
244     const uint64_t cu_offset_;
245     string cu_name_;
246     bool printed_cu_header_;
247     bool printed_unpaired_header_;
248     bool uncovered_warnings_enabled_;
249 
250    private:
251     // Print a per-CU heading, once.
252     void CUHeading();
253     // Print an unpaired function/line heading, once.
254     void UncoveredHeading();
255   };
256 
257   // Create a DWARF debugging info handler for a compilation unit
258   // within FILE_CONTEXT. This uses information received from the
259   // CompilationUnit DWARF parser to populate
260   // FILE_CONTEXT->module. Use LINE_READER to handle the compilation
261   // unit's line number data. Use REPORTER to report problems with the
262   // data we find.
263   DwarfCUToModule(FileContext* file_context,
264                   LineToModuleHandler* line_reader,
265                   RangesHandler* ranges_handler,
266                   WarningReporter* reporter,
267                   bool handle_inline = false,
268                   uint64_t low_pc = 0,
269                   uint64_t addr_base = 0,
270                   bool has_source_line_info = false,
271                   uint64_t source_line_offset = 0);
272   ~DwarfCUToModule();
273 
274   void ProcessAttributeSigned(enum DwarfAttribute attr,
275                               enum DwarfForm form,
276                               int64_t data);
277   void ProcessAttributeUnsigned(enum DwarfAttribute attr,
278                                 enum DwarfForm form,
279                                 uint64_t data);
280   void ProcessAttributeString(enum DwarfAttribute attr,
281                               enum DwarfForm form,
282                               const string& data);
283   bool EndAttributes();
284   DIEHandler* FindChildHandler(uint64_t offset, enum DwarfTag tag);
285 
286   // Assign all our source Lines to the Functions that cover their
287   // addresses, and then add them to module_.
288   void Finish();
289 
290   bool StartCompilationUnit(uint64_t offset, uint8_t address_size,
291                             uint8_t offset_size, uint64_t cu_length,
292                             uint8_t dwarf_version);
293   bool StartRootDIE(uint64_t offset, enum DwarfTag tag);
294 
295  private:
296   // Used internally by the handler. Full definitions are in
297   // dwarf_cu_to_module.cc.
298   struct CUContext;
299   struct DIEContext;
300   struct Specification;
301   class GenericDIEHandler;
302   class FuncHandler;
303   class InlineHandler;
304   class NamedScopeHandler;
305 
306   // A map from section offsets to specifications.
307   typedef map<uint64_t, Specification> SpecificationByOffset;
308 
309   // Set this compilation unit's source language to LANGUAGE.
310   void SetLanguage(DwarfLanguage language);
311 
312   // Read source line information at OFFSET in the .debug_line
313   // section.  Record source files in module_, but record source lines
314   // in lines_; we apportion them to functions in
315   // AssignLinesToFunctions.
316   void ReadSourceLines(uint64_t offset);
317 
318   // Assign the lines in lines_ to the individual line lists of the
319   // functions in functions_.  (DWARF line information maps an entire
320   // compilation unit at a time, and gives no indication of which
321   // lines belong to which functions, beyond their addresses.)
322   void AssignLinesToFunctions();
323 
324   void AssignFilesToInlines();
325 
326   // The only reason cu_context_ and child_context_ are pointers is
327   // that we want to keep their definitions private to
328   // dwarf_cu_to_module.cc, instead of listing them all here. They are
329   // owned by this DwarfCUToModule: the constructor sets them, and the
330   // destructor deletes them.
331 
332   // The handler to use to handle line number data.
333   LineToModuleHandler* line_reader_;
334 
335   // This compilation unit's context.
336   scoped_ptr<CUContext> cu_context_;
337 
338   // A context for our children.
339   scoped_ptr<DIEContext> child_context_;
340 
341   // True if this compilation unit has source line information.
342   bool has_source_line_info_;
343 
344   // The offset of this compilation unit's line number information in
345   // the .debug_line section.
346   uint64_t source_line_offset_;
347 
348   // The line numbers we have seen thus far.  We accumulate these here
349   // during parsing.  Then, in Finish, we call AssignLinesToFunctions
350   // to dole them out to the appropriate functions.
351   vector<Module::Line> lines_;
352 
353   // The map from file index to File* in this CU.
354   std::map<uint32_t, Module::File*> files_;
355 };
356 
357 }  // namespace google_breakpad
358 
359 #endif  // COMMON_LINUX_DWARF_CU_TO_MODULE_H__
360