Improve backtrace formating while panicking.

- `RUST_BACKTRACE=full` prints all the informations (old behaviour)
- `RUST_BACKTRACE=(0|no)` disables the backtrace.
- `RUST_BACKTRACE=<everything else>` (including `1`) shows a simplified
  backtrace, without the function addresses and with cleaned filenames
  and symbols. Also removes some unneded frames at the beginning and the
  end.

Fixes #37783.

PR is #38165.

1 files changed, 8 insertions, 3 deletions

diff --git a/src/libstd/sys/redox/backtrace.rs b/src/libstd/sys/redox/backtrace.rs
index 6f53841502a..961148fb6b4 100644
--- a/src/libstd/sys/redox/backtrace.rs
+++ b/src/libstd/sys/redox/backtrace.rs
@@ -10,9 +10,14 @@
 
 use libc;
 use io;
-use sys_common::backtrace::output;
+use sys_common::backtrace::Frame;
+
+pub use sys_common::gnu::libbacktrace::*;
+pub struct BacktraceContext;
 
 #[inline(never)]
-pub fn write(w: &mut io::Write) -> io::Result<()> {
-    output(w, 0, 0 as *mut libc::c_void, None)
+pub fn unwind_backtrace(frames: &mut [Frame])
+    -> io::Result<(usize, BacktraceContext)>
+{
+    Ok((0, BacktraceContext))
 }