Implement basic stack traces on Android and reenable unit tests.

base/debug/stack_trace_android.cc

Index: base/debug/stack_trace_android.cc
diff --git a/base/debug/stack_trace_android.cc b/base/debug/stack_trace_android.cc
index 050a2d8c501904b17e3bee5cf13993fafd639026..7c567a3e186de5c4b52cd8a5389c51ba125a7248 100644
--- a/base/debug/stack_trace_android.cc
+++ b/base/debug/stack_trace_android.cc
@@ -8,8 +8,9 @@
 #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.
@@ -96,6 +97,9 @@ StackTrace::StackTrace() {
 // 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);
@@ -118,7 +122,33 @@ void StackTrace::PrintBacktrace() const {
 }
 
 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