Rollup merge of rust-lang#56718 - RalfJung:use-libbacktrace-printing, r=alexcrichton

Use libbacktrace pretty-printing

r? @alexcrichton

Author: pietroalbini

Cargo.lock

@@ -81,7 +81,7 @@ dependencies = [
 
 [[package]]
 name = "backtrace"
-version = "0.3.9"
+version = "0.3.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "backtrace-sys 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -728,15 +728,15 @@ name = "error-chain"
 version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "backtrace 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "backtrace 0.3.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "error-chain"
 version = "0.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "backtrace 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "backtrace 0.3.11 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -751,7 +751,7 @@ name = "failure"
 version = "0.1.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "backtrace 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "backtrace 0.3.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "failure_derive 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -2060,7 +2060,7 @@ name = "rustc"
 version = "0.0.0"
 dependencies = [
  "arena 0.0.0",
- "backtrace 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "backtrace 0.3.11 (registry+https://github.com/rust-lang/crates.io-index)",
  "bitflags 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "chalk-engine 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -3380,7 +3380,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum arrayvec 0.4.7 (registry+https://github.com/rust-lang/crates.io-index)" = "a1e964f9e24d588183fcb43503abda40d288c8657dfc27311516ce2f05675aef"
 "checksum assert_cli 0.6.2 (registry+https://github.com/rust-lang/crates.io-index)" = "98589b0e465a6c510d95fceebd365bb79bedece7f6e18a480897f2015f85ec51"
 "checksum atty 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "9a7d5b8723950951411ee34d271d99dddcc2035a16ab25310ea2c8cfd4369652"
-"checksum backtrace 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)" = "89a47830402e9981c5c41223151efcced65a0510c13097c769cede7efb34782a"
+"checksum backtrace 0.3.11 (registry+https://github.com/rust-lang/crates.io-index)" = "18b65ea1161bfb2dd6da6fade5edd4dbd08fba85012123dd333d2fd1b90b2782"
 "checksum backtrace-sys 0.1.24 (registry+https://github.com/rust-lang/crates.io-index)" = "c66d56ac8dabd07f6aacdaf633f4b8262f5b3601a810a0dcddffd5c22c69daa0"
 "checksum bit-set 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "6f1efcc46c18245a69c38fcc5cc650f16d3a59d034f3106e9ed63748f695730a"
 "checksum bit-vec 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "4440d5cb623bb7390ae27fec0bb6c61111969860f8e3ae198bfa0663645e67cf"

src/librustc/mir/interpret/error.rs

@@ -183,50 +183,14 @@ pub struct EvalError<'tcx> {
 impl<'tcx> EvalError<'tcx> {
     pub fn print_backtrace(&mut self) {
         if let Some(ref mut backtrace) = self.backtrace {
-            eprintln!("{}", print_backtrace(&mut *backtrace));
+            print_backtrace(&mut *backtrace);
         }
     }
 }
 
-fn print_backtrace(backtrace: &mut Backtrace) -> String {
-    use std::fmt::Write;
-
+fn print_backtrace(backtrace: &mut Backtrace) {
     backtrace.resolve();
-
-    let mut trace_text = "\n\nAn error occurred in miri:\n".to_string();
-    write!(trace_text, "backtrace frames: {}\n", backtrace.frames().len()).unwrap();
-    'frames: for (i, frame) in backtrace.frames().iter().enumerate() {
-        if frame.symbols().is_empty() {
-            write!(trace_text, "  {}: no symbols\n", i).unwrap();
-        }
-        let mut first = true;
-        for symbol in frame.symbols() {
-            if first {
-                write!(trace_text, "  {}: ", i).unwrap();
-                first = false;
-            } else {
-                let len = i.to_string().len();
-                write!(trace_text, "  {}  ", " ".repeat(len)).unwrap();
-            }
-            if let Some(name) = symbol.name() {
-                write!(trace_text, "{}\n", name).unwrap();
-            } else {
-                write!(trace_text, "<unknown>\n").unwrap();
-            }
-            write!(trace_text, "           at ").unwrap();
-            if let Some(file_path) = symbol.filename() {
-                write!(trace_text, "{}", file_path.display()).unwrap();
-            } else {
-                write!(trace_text, "<unknown_file>").unwrap();
-            }
-            if let Some(line) = symbol.lineno() {
-                write!(trace_text, ":{}\n", line).unwrap();
-            } else {
-                write!(trace_text, "\n").unwrap();
-            }
-        }
-    }
-    trace_text
+    eprintln!("\n\nAn error occurred in miri:\n{:?}", backtrace);
 }
 
 impl<'tcx> From<EvalErrorKind<'tcx, u64>> for EvalError<'tcx> {
@@ -238,7 +202,7 @@ impl<'tcx> From<EvalErrorKind<'tcx, u64>> for EvalError<'tcx> {
 
                 if val == "immediate" {
                     // Print it now
-                    eprintln!("{}", print_backtrace(&mut backtrace));
+                    print_backtrace(&mut backtrace);
                     None
                 } else {
                     Some(Box::new(backtrace))