From 46756821c4fe238f12a6e5ea18c356398f8d8795 Mon Sep 17 00:00:00 2001
From: Christopher Ferris <cferris@google.com>
Date: Tue, 14 Jan 2014 20:16:30 -0800
Subject: Rewrite libbacktrace to be all C++.

This includes removing the map_info.c source and replacing it with the
BacktraceMap class to handle all map related code.

Change all callers of libbacktrace map functionality.

Also modify the corkscrew thread code so that it doesn't need to build
the map twice (once in the corkscrew format and once in the libbacktrace
format).

Change-Id: I32865a39f83a3dd6f958fc03c2759ba47d12382e
---
 libbacktrace/UnwindCurrent.cpp | 49 ++++++++++++++++--------------------------
 1 file changed, 19 insertions(+), 30 deletions(-)

(limited to 'libbacktrace/UnwindCurrent.cpp')

diff --git a/libbacktrace/UnwindCurrent.cpp b/libbacktrace/UnwindCurrent.cpp
index 6cdbc42..747eb21 100644
--- a/libbacktrace/UnwindCurrent.cpp
+++ b/libbacktrace/UnwindCurrent.cpp
@@ -18,9 +18,8 @@
 
 #include <sys/types.h>
 
-#include <cutils/log.h>
-
-#include <backtrace/backtrace.h>
+#include <backtrace/Backtrace.h>
+#include <backtrace/BacktraceMap.h>
 
 #define UNW_LOCAL_ONLY
 #include <libunwind.h>
@@ -79,9 +78,6 @@ std::string UnwindCurrent::GetFunctionNameRaw(uintptr_t pc, uintptr_t* offset) {
 }
 
 bool UnwindCurrent::UnwindFromContext(size_t num_ignore_frames, bool resolve) {
-  backtrace_t* backtrace = GetBacktraceData();
-  backtrace->num_frames = 0;
-
   // The cursor structure is pretty large, do not put it on the stack.
   unw_cursor_t* cursor = new unw_cursor_t;
   int ret = unw_init_local(cursor, &context_);
@@ -91,6 +87,9 @@ bool UnwindCurrent::UnwindFromContext(size_t num_ignore_frames, bool resolve) {
     return false;
   }
 
+  std::vector<backtrace_frame_data_t>* frames = GetFrames();
+  frames->reserve(MAX_BACKTRACE_FRAMES);
+  size_t num_frames = 0;
   do {
     unw_word_t pc;
     ret = unw_get_reg(cursor, UNW_REG_IP, &pc);
@@ -106,42 +105,32 @@ bool UnwindCurrent::UnwindFromContext(size_t num_ignore_frames, bool resolve) {
     }
 
     if (num_ignore_frames == 0) {
-      size_t num_frames = backtrace->num_frames;
-      backtrace_frame_data_t* frame = &backtrace->frames[num_frames];
+      frames->resize(num_frames+1);
+      backtrace_frame_data_t* frame = &frames->at(num_frames);
       frame->num = num_frames;
       frame->pc = static_cast<uintptr_t>(pc);
       frame->sp = static_cast<uintptr_t>(sp);
       frame->stack_size = 0;
-      frame->map_name = NULL;
-      frame->map_offset = 0;
-      frame->func_name = NULL;
-      frame->func_offset = 0;
 
       if (num_frames > 0) {
         // Set the stack size for the previous frame.
-        backtrace_frame_data_t* prev = &backtrace->frames[num_frames-1];
+        backtrace_frame_data_t* prev = &frames->at(num_frames-1);
         prev->stack_size = frame->sp - prev->sp;
       }
 
       if (resolve) {
-        std::string func_name = backtrace_obj_->GetFunctionName(frame->pc, &frame->func_offset);
-        if (!func_name.empty()) {
-          frame->func_name = strdup(func_name.c_str());
-        }
-
-        uintptr_t map_start;
-        frame->map_name = backtrace_obj_->GetMapName(frame->pc, &map_start);
-        if (frame->map_name) {
-          frame->map_offset = frame->pc - map_start;
-        }
+        frame->func_name = backtrace_obj_->GetFunctionName(frame->pc, &frame->func_offset);
+        frame->map = backtrace_obj_->FindMap(frame->pc);
+      } else {
+        frame->map = NULL;
+        frame->func_offset = 0;
       }
-
-      backtrace->num_frames++;
+      num_frames++;
     } else {
       num_ignore_frames--;
     }
     ret = unw_step (cursor);
-  } while (ret > 0 && backtrace->num_frames < MAX_BACKTRACE_FRAMES);
+  } while (ret > 0 && num_frames < MAX_BACKTRACE_FRAMES);
 
   delete cursor;
   return true;
@@ -195,11 +184,11 @@ void UnwindThread::ThreadUnwind(
 //-------------------------------------------------------------------------
 // C++ object creation function.
 //-------------------------------------------------------------------------
-Backtrace* CreateCurrentObj(backtrace_map_info_t* map_info) {
-  return new BacktraceCurrent(new UnwindCurrent(), map_info);
+Backtrace* CreateCurrentObj(BacktraceMap* map) {
+  return new BacktraceCurrent(new UnwindCurrent(), map);
 }
 
-Backtrace* CreateThreadObj(pid_t tid, backtrace_map_info_t* map_info) {
+Backtrace* CreateThreadObj(pid_t tid, BacktraceMap* map) {
   UnwindThread* thread_obj = new UnwindThread();
-  return new BacktraceThread(thread_obj, thread_obj, tid, map_info);
+  return new BacktraceThread(thread_obj, thread_obj, tid, map);
 }
-- 
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