Move from libbacktrace to libunwindstack.

Use the new AndroidUnwinder object to replace the libbacktrace version.

Bug: 120606663

Test: Run unit tests.
Test: Force a call to CallStack::log() and verify the backtrace is
Test: reasonable.
Change-Id: I73d909821a33f716d7b0e0997d43c6ab11c7c4f9

2 files changed, 10 insertions, 7 deletions

diff --git a/opengl/libs/Android.bp b/opengl/libs/Android.bp
index c9fce8ad52..c1e935aab0 100644
--- a/opengl/libs/Android.bp
+++ b/opengl/libs/Android.bp
@@ -108,7 +108,6 @@ cc_defaults {
         // In particular, DO NOT add libutils nor anything "above" libui
         "libgraphicsenv",
         "libnativewindow",
-        "libbacktrace",
         "libbase",
     ],
 }
@@ -165,6 +164,7 @@ cc_library_shared {
         "libnativeloader_lazy",
         "libutils",
         "libSurfaceFlingerProp",
+        "libunwindstack",
     ],
     static_libs: [
         "libEGL_getProcAddress",
diff --git a/opengl/libs/EGL/CallStack.h b/opengl/libs/EGL/CallStack.h
index b7fdf97cbe..96437c37d9 100644
--- a/opengl/libs/EGL/CallStack.h
+++ b/opengl/libs/EGL/CallStack.h
@@ -16,8 +16,8 @@
 
 #pragma once
 
-#include <backtrace/Backtrace.h>
 #include <log/log.h>
+#include <unwindstack/AndroidUnwinder.h>
 
 #include <memory>
 
@@ -26,12 +26,15 @@ public:
     // Create a callstack with the current thread's stack trace.
     // Immediately dump it to logcat using the given logtag.
     static void log(const char* logtag) noexcept {
-        std::unique_ptr<Backtrace> backtrace(
-                Backtrace::Create(BACKTRACE_CURRENT_PROCESS, BACKTRACE_CURRENT_THREAD));
-        if (backtrace->Unwind(2)) {
-            for (size_t i = 0, c = backtrace->NumFrames(); i < c; i++) {
+        unwindstack::AndroidLocalUnwinder unwinder;
+        unwindstack::AndroidUnwinderData data;
+        if (unwinder.Unwind(data)) {
+            for (size_t i = 2, c = data.frames.size(); i < c; i++) {
+                auto& frame = data.frames[i];
+                // Trim the first two frames.
+                frame.num -= 2;
                 __android_log_print(ANDROID_LOG_DEBUG, logtag, "%s",
-                                    backtrace->FormatFrameData(i).c_str());
+                                    unwinder.FormatFrame(frame).c_str());
             }
         }
     }