Implement basic stack traces on Android and reenable unit tests.

base/debug/stack_trace_android.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/debug/stack_trace.h"
 
 #include <signal.h>
 #include <sys/types.h>
 #include <unistd.h>
 #include <unwind.h>  // TODO(dmikurube): Remove.  See http://crbug.com/236855.
+#include <iomanip>
 
-#include "base/logging.h"
+#include "base/third_party/symbolize/symbolize.h"
 
 #ifdef __MIPSEL__
 // SIGSTKFLT is not defined for MIPS.
 #define SIGSTKFLT SIGSEGV
 #endif
 
 // TODO(dmikurube): Remove when Bionic's get_backtrace() gets popular.
 // See http://crbug.com/236855.
 namespace {
 
@@ skipping 66 matching lines @@
   // See http://crbug.com/236855.
   stack_crawl_state_t state(reinterpret_cast<uintptr_t*>(trace_), kMaxTraces);
   _Unwind_Backtrace(tracer, &state);
   count_ = state.frame_count;
   // TODO(dmikurube): Symbolize in Chrome.
 }
 
 // Sends fake SIGSTKFLT signals to let the Android linker and debuggerd dump
 // stack. See inlined comments and Android bionic/linker/debugger.c and
 // system/core/debuggerd/debuggerd.c for details.
+//
+// TODO(scherkus): This should probably use OutputToStream() and print to
+// stderr. Instead it crashes the program http://crbug.com/248775
 void StackTrace::PrintBacktrace() const {
   // Get the current handler of SIGSTKFLT for later use.
   sighandler_t sig_handler = signal(SIGSTKFLT, SIG_DFL);
   signal(SIGSTKFLT, sig_handler);
 
   // The Android linker will handle this signal and send a stack dumping request
   // to debuggerd which will ptrace_attach this process. Before returning from
   // the signal handler, the linker sets the signal handler to SIG_IGN.
   kill(gettid(), SIGSTKFLT);
 
   // Because debuggerd will wait for the process to be stopped by the actual
   // signal in crashing scenarios, signal is sent again to met the expectation.
   // Debuggerd will dump stack into the system log and /data/tombstones/ files.
   // NOTE: If this process runs in the interactive shell, it will be put
   // in the background. To resume it in the foreground, use 'fg' command.
   kill(gettid(), SIGSTKFLT);
 
   // Restore the signal handler so that this method can work the next time.
   signal(SIGSTKFLT, sig_handler);
 }
 
 void StackTrace::OutputToStream(std::ostream* os) const {
-  NOTIMPLEMENTED();
+  std::ios_base::fmtflags flags = os->flags();
+
+  for (size_t i = 0; i < count_; ++i) {
+    // NOTE: Native libraries in APKs are stripped before installing. Print out
+    // the relocatable address and library names so host computers can use tools
+    // to symbolize and demangle (e.g., addr2line, c++filt).
+    char path[1024];
+    uint64 start_address;

[satorux1, 2013/06/13 01:58:10]

Please move them to where these are used.

I'd also suggest to initialize start_address with 0, to be extra defensive. it's
more like a habit, though.

[scherkus (not reviewing), 2013/06/13 02:20:46]

Done.

+
+    *os << "#" << std::dec << std::setfill('0') << std::setw(2) << i << " ";

[satorux1, 2013/06/13 01:58:10]

For formatting, I think base::StringPrintf() is more common than streams in
Chrome code, and easier to read.

If you plan to make this async-signal-safe, you should format this in a very low
level fashion. stack_trace_posix.cc does thi using itoa_r(). That may be too
much work to do in this first version.

[scherkus (not reviewing), 2013/06/13 02:20:46]

Yeah -- part of me wanted to make things async safe from the get-go, but that's
a bit too much for V1.

Also after I figure out what's going on with http://crbug.com/248775 and some
other related work I have a feeling we could possibly merge this in w/ the posix
code

[satorux1, 2013/06/13 03:34:25]

For now, maybe add a TODO comment?

+
+    // Subtract by one as return address of function may be in the next
+    // function when a function is annotated as noreturn.
+    void* address = static_cast<char*>(trace_[i]) - 1;
+    if (google::FindObjectFileNameContainingPcAndGetStartAddress(
+            address, path, sizeof(path), &start_address)) {
+      uintptr_t rel_pc = reinterpret_cast<uintptr_t>(address) - start_address;
+      *os << "pc " << std::hex << std::setfill('0') << std::setw(8) << rel_pc
+          << " " << path;
+    } else {
+      *os << "<unknown>";
+    }
+
+    *os << "\n";
+  }
+
+  os->flags(flags);
 }
 
 }  // namespace debug
 }  // namespace base