Auto merge of #1575 - Aaron1011:fix/macro-backtrace, r=oli-obk

Use macro callsite spans in backtrace

This mirrors what we do in the debuginfo used for runtime backtraces.

Author: bors

src/shims/backtrace.rs

@@ -26,7 +26,13 @@ pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx
 
         let mut data = Vec::new();
         for frame in this.active_thread_stack().iter().rev() {
-            data.push((frame.instance, frame.current_span().lo()));
+            let mut span = frame.current_span();
+            // Match the behavior of runtime backtrace spans
+            // by using a non-macro span in our backtrace. See `FunctionCx::debug_loc`.
+            if span.from_expansion() && !tcx.sess.opts.debugging_opts.debug_macros {
+                span = rustc_span::hygiene::walk_chain(span, frame.body.span.ctxt())
+            }
+            data.push((frame.instance, span.lo()));
         }
 
         let ptrs: Vec<_> = data.into_iter().map(|(instance, pos)| {

tests/run-pass/backtrace-api.rs

@@ -18,7 +18,13 @@ struct MiriFrame {
 
 #[inline(never)] fn func_a() -> Box<[*mut ()]> { func_b::<u8>() }
 #[inline(never)] fn func_b<T>() -> Box<[*mut ()]> { func_c() }
-#[inline(never)] fn func_c() -> Box<[*mut ()]> { unsafe { miri_get_backtrace(0) } }
+
+macro_rules! invoke_func_d {
+    () => { func_d() }
+}
+
+#[inline(never)] fn func_c() -> Box<[*mut ()]> { invoke_func_d!() }
+#[inline(never)] fn func_d() -> Box<[*mut ()]> { unsafe { miri_get_backtrace(0) } }
 
 fn main() {
     let mut seen_main = false;

tests/run-pass/backtrace-api.stderr

@@ -1,7 +1,8 @@
-$DIR/backtrace-api.rs:21:59 (func_c)
+$DIR/backtrace-api.rs:27:59 (func_d)
+$DIR/backtrace-api.rs:26:50 (func_c)
 $DIR/backtrace-api.rs:20:53 (func_b)
 $DIR/backtrace-api.rs:19:50 (func_a)
-$DIR/backtrace-api.rs:25:18 (main)
+$DIR/backtrace-api.rs:31:18 (main)
 RUSTLIB/core/src/ops/function.rs:LL:COL (<fn() as std::ops::FnOnce<()>>::call_once - shim(fn()))
 RUSTLIB/std/src/sys_common/backtrace.rs:LL:COL (std::sys_common::backtrace::__rust_begin_short_backtrace)
 RUSTLIB/std/src/rt.rs:LL:COL (std::rt::lang_start::{closure#0})

tests/run-pass/backtrace-api.stdout

@@ -1,4 +1,5 @@
-$DIR/backtrace-api.rs:21:59 (func_c)
+$DIR/backtrace-api.rs:27:59 (func_d)
+$DIR/backtrace-api.rs:26:50 (func_c)
 $DIR/backtrace-api.rs:20:53 (func_b::<u8>)
 $DIR/backtrace-api.rs:19:50 (func_a)
-$DIR/backtrace-api.rs:25:18 (main)
+$DIR/backtrace-api.rs:31:18 (main)