Add arch member into Unwinder object.

This simplifies some of the logic and removes the need to pass an
Arch value to functions that should already know about the arch
it is operating on.

Includes fixes for debuggerd/libbacktrace.

Added new unit tests to cover new cases.

Test: All unit tests pass.
Test: Faked unwinder failing to verify debuggerd error messages display
Test: properly in backtrace and tombstone.
Change-Id: I439fcae0695befcfb1cb4c0a786cc74949d33425

1 files changed, 3 insertions, 7 deletions

diff --git a/debuggerd/handler/debuggerd_fallback.cpp b/debuggerd/handler/debuggerd_fallback.cpp
index 9bcbdb36a..abcb2c4ed 100644
--- a/debuggerd/handler/debuggerd_fallback.cpp
+++ b/debuggerd/handler/debuggerd_fallback.cpp
@@ -82,16 +82,12 @@ static void debuggerd_fallback_trace(int output_fd, ucontext_t* ucontext) {
     thread.pid = getpid();
     thread.tid = gettid();
     thread.thread_name = get_thread_name(gettid());
-    unwindstack::ArchEnum arch = unwindstack::Regs::CurrentArch();
-    thread.registers.reset(unwindstack::Regs::CreateFromUcontext(arch, ucontext));
+    thread.registers.reset(
+        unwindstack::Regs::CreateFromUcontext(unwindstack::Regs::CurrentArch(), ucontext));
 
     // TODO: Create this once and store it in a global?
     unwindstack::UnwinderFromPid unwinder(kMaxFrames, getpid());
-    if (unwinder.Init(arch)) {
-      dump_backtrace_thread(output_fd, &unwinder, thread);
-    } else {
-      async_safe_format_log(ANDROID_LOG_ERROR, "libc", "Unable to init unwinder.");
-    }
+    dump_backtrace_thread(output_fd, &unwinder, thread);
   }
   __linker_disable_fallback_allocator();
 }