Add function to trace stack using frame pointers.

base/debug/stack_trace_posix.cc

Index: base/debug/stack_trace_posix.cc
diff --git a/base/debug/stack_trace_posix.cc b/base/debug/stack_trace_posix.cc
index fc3ee14c7b9d60958ad6d6000d94cbc616b6c7df..06edf0a4cb126319e6f02455b9d05a5fb1626841 100644
--- a/base/debug/stack_trace_posix.cc
+++ b/base/debug/stack_trace_posix.cc
@@ -743,6 +743,52 @@ void StackTrace::OutputToStream(std::ostream* os) const {
 }
 #endif
 
+#if HAVE_TRACE_STACK_FRAME_POINTERS
+
+size_t TraceStackFramePointers(const void** out_trace,
+                               size_t max_depth,
+                               size_t skip_count) {
+  uintptr_t fp = reinterpret_cast<uintptr_t>(__builtin_frame_address(0));
+
+  size_t depth = 0;
+  while (fp && depth < max_depth) {
+    if (skip_count != 0) {
+      skip_count--;
+    } else {
+      out_trace[depth++] = reinterpret_cast<const void**>(fp)[1];
+    }
+
+    // Find out next frame pointer
+    // (heuristics are from TCMalloc's stacktrace functions)
+    {
+      uintptr_t next_fp = reinterpret_cast<const uintptr_t*>(fp)[0];
+
+      // With the stack growing downwards, older stack frame must be
+      // at a greater address that the current one.
+      if (next_fp <= fp) break;
+
+      // Assume stack frames larger than 100,000 bytes are bogus.
+      if (next_fp - fp > 100000) break;
+
+      // Check alignment.
+      if (next_fp & (sizeof(void*) - 1)) break;
+
+#ifdef __i386__
+      // On 64-bit machines, the stack pointer can be very close to

[bcwhite, 2016/04/13 12:36:24]

You say 64-bit but have 32-bit numbers.

[Dmitry Skiba, 2016/04/15 07:31:56]

This code came from TCMalloc's stacktrace_x86-inl.h, and it appears to be very
old - it was there in 2005. So I guess I'll just remove this hack.

+      // 0xffffffff, so we explicitly check for a pointer into the
+      // last two pages in the address fpace

[bcwhite, 2016/04/13 12:36:24]

What is special about the last two pages?  Should this be checked before the
first fp is dereferenced on line 764?

+      if (next_fp >= 0xffffe000) break;
+#endif
+
+      fp = next_fp;
+    }
+  }
+
+  return depth;
+}
+
+#endif  // HAVE_TRACE_STACK_FRAME_POINTERS
+
 namespace internal {
 
 // NOTE: code from sandbox/linux/seccomp-bpf/demo.cc.