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29 
30 // Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
31 
32 // dump_stabs.cc --- implement the StabsToModule class.
33 
34 #include <assert.h>
35 #include <cxxabi.h>
36 #include <stdarg.h>
37 
38 #include <algorithm>
39 
40 #include "common/stabs_to_module.h"
41 
42 namespace google_breakpad {
43 
44 using std::string;
45 
46 // Demangle using abi call.
47 // Older GCC may not support it.
Demangle(const string & mangled)48 static string Demangle(const string &mangled) {
49   int status = 0;
50   char *demangled = abi::__cxa_demangle(mangled.c_str(), NULL, NULL, &status);
51   if (status == 0 && demangled != NULL) {
52     string str(demangled);
53     free(demangled);
54     return str;
55   }
56   return string(mangled);
57 }
58 
~StabsToModule()59 StabsToModule::~StabsToModule() {
60   // Free any functions we've accumulated but not added to the module.
61   for (vector<Module::Function *>::const_iterator func_it = functions_.begin();
62        func_it != functions_.end(); func_it++)
63     delete *func_it;
64   // Free any function that we're currently within.
65   delete current_function_;
66 }
67 
StartCompilationUnit(const char * name,uint64_t address,const char * build_directory)68 bool StabsToModule::StartCompilationUnit(const char *name, uint64_t address,
69                                          const char *build_directory) {
70   assert(!in_compilation_unit_);
71   in_compilation_unit_ = true;
72   current_source_file_name_ = name;
73   current_source_file_ = module_->FindFile(name);
74   comp_unit_base_address_ = address;
75   boundaries_.push_back(static_cast<Module::Address>(address));
76   return true;
77 }
78 
EndCompilationUnit(uint64_t address)79 bool StabsToModule::EndCompilationUnit(uint64_t address) {
80   assert(in_compilation_unit_);
81   in_compilation_unit_ = false;
82   comp_unit_base_address_ = 0;
83   current_source_file_ = NULL;
84   current_source_file_name_ = NULL;
85   if (address)
86     boundaries_.push_back(static_cast<Module::Address>(address));
87   return true;
88 }
89 
StartFunction(const string & name,uint64_t address)90 bool StabsToModule::StartFunction(const string &name,
91                                   uint64_t address) {
92   assert(!current_function_);
93   Module::Function *f = new Module::Function;
94   f->name = Demangle(name);
95   f->address = address;
96   f->size = 0;           // We compute this in StabsToModule::Finalize().
97   f->parameter_size = 0; // We don't provide this information.
98   current_function_ = f;
99   boundaries_.push_back(static_cast<Module::Address>(address));
100   return true;
101 }
102 
EndFunction(uint64_t address)103 bool StabsToModule::EndFunction(uint64_t address) {
104   assert(current_function_);
105   // Functions in this compilation unit should have address bigger
106   // than the compilation unit's starting address.  There may be a lot
107   // of duplicated entries for functions in the STABS data. We will
108   // count on the Module to remove the duplicates.
109   if (current_function_->address >= comp_unit_base_address_)
110     functions_.push_back(current_function_);
111   else
112     delete current_function_;
113   current_function_ = NULL;
114   if (address)
115     boundaries_.push_back(static_cast<Module::Address>(address));
116   return true;
117 }
118 
Line(uint64_t address,const char * name,int number)119 bool StabsToModule::Line(uint64_t address, const char *name, int number) {
120   assert(current_function_);
121   assert(current_source_file_);
122   if (name != current_source_file_name_) {
123     current_source_file_ = module_->FindFile(name);
124     current_source_file_name_ = name;
125   }
126   Module::Line line;
127   line.address = address;
128   line.size = 0;  // We compute this in StabsToModule::Finalize().
129   line.file = current_source_file_;
130   line.number = number;
131   current_function_->lines.push_back(line);
132   return true;
133 }
134 
Extern(const string & name,uint64_t address)135 bool StabsToModule::Extern(const string &name, uint64_t address) {
136   Module::Extern *ext = new Module::Extern;
137   // Older libstdc++ demangle implementations can crash on unexpected
138   // input, so be careful about what gets passed in.
139   if (name.compare(0, 3, "__Z") == 0) {
140     ext->name = Demangle(name.substr(1));
141   } else if (name[0] == '_') {
142     ext->name = name.substr(1);
143   } else {
144     ext->name = name;
145   }
146   ext->address = address;
147   module_->AddExtern(ext);
148   return true;
149 }
150 
Warning(const char * format,...)151 void StabsToModule::Warning(const char *format, ...) {
152   va_list args;
153   va_start(args, format);
154   vfprintf(stderr, format, args);
155   va_end(args);
156 }
157 
Finalize()158 void StabsToModule::Finalize() {
159   // Sort our boundary list, so we can search it quickly.
160   sort(boundaries_.begin(), boundaries_.end());
161   // Sort all functions by address, just for neatness.
162   sort(functions_.begin(), functions_.end(),
163        Module::Function::CompareByAddress);
164 
165   for (vector<Module::Function *>::const_iterator func_it = functions_.begin();
166        func_it != functions_.end();
167        func_it++) {
168     Module::Function *f = *func_it;
169     // Compute the function f's size.
170     vector<Module::Address>::const_iterator boundary
171         = std::upper_bound(boundaries_.begin(), boundaries_.end(), f->address);
172     if (boundary != boundaries_.end())
173       f->size = *boundary - f->address;
174     else
175       // If this is the last function in the module, and the STABS
176       // reader was unable to give us its ending address, then assign
177       // it a bogus, very large value.  This will happen at most once
178       // per module: since we've added all functions' addresses to the
179       // boundary table, only one can be the last.
180       f->size = kFallbackSize;
181 
182     // Compute sizes for each of the function f's lines --- if it has any.
183     if (!f->lines.empty()) {
184       stable_sort(f->lines.begin(), f->lines.end(),
185                   Module::Line::CompareByAddress);
186       vector<Module::Line>::iterator last_line = f->lines.end() - 1;
187       for (vector<Module::Line>::iterator line_it = f->lines.begin();
188            line_it != last_line; line_it++)
189         line_it[0].size = line_it[1].address - line_it[0].address;
190       // Compute the size of the last line from f's end address.
191       last_line->size = (f->address + f->size) - last_line->address;
192     }
193   }
194   // Now that everything has a size, add our functions to the module, and
195   // dispose of our private list.
196   module_->AddFunctions(functions_.begin(), functions_.end());
197   functions_.clear();
198 }
199 
200 } // namespace google_breakpad
201