Pass Miri with -Zmiri-strict-provenance

Author: saethlin

src/capture.rs

@@ -2,6 +2,7 @@ use crate::PrintFmt;
 use crate::{resolve, resolve_frame, trace, BacktraceFmt, Symbol, SymbolName};
 use std::ffi::c_void;
 use std::fmt;
+use std::mem;
 use std::path::{Path, PathBuf};
 use std::prelude::v1::*;
 
@@ -334,7 +335,13 @@ impl BacktraceSymbol {
     /// This function requires the `std` feature of the `backtrace` crate to be
     /// enabled, and the `std` feature is enabled by default.
     pub fn addr(&self) -> Option<*mut c_void> {
-        self.addr.map(|s| s as *mut c_void)
+        // To be compatible with strict provenance, we can't cast here.
+        // The most right thing to do is always store addr as a pointer,
+        // but that runs into problems with !Send + !Sync.
+        // In any case, we're never going to dereference this pointer, so
+        // a hand-written version of ptr::invalid_mut suffices.
+        self.addr
+            .map(|s| unsafe { mem::transmute::<usize, *mut c_void>(s) })
     }
 
     /// Same as `Symbol::filename`

tests/skip_inner_frames.rs

@@ -23,7 +23,6 @@ fn backtrace_new_unresolved_should_start_with_call_site_trace() {
     assert!(!b.frames().is_empty());
 
     let this_ip = backtrace_new_unresolved_should_start_with_call_site_trace as usize;
-    println!("this_ip: {:?}", this_ip as *const usize);
     let frame_ip = b.frames().first().unwrap().symbol_address() as usize;
     assert_eq!(this_ip, frame_ip);
 }

tests/smoke.rs

@@ -290,7 +290,6 @@ fn sp_smoke_test() {
             });
 
             let sp = frame.sp() as usize;
-            eprintln!("sp  = {:p}", sp as *const u8);
             if sp == 0 {
                 // If the SP is null, then we don't have an implementation for
                 // getting the SP on this target. Just keep walking the stack,
@@ -306,7 +305,6 @@ fn sp_smoke_test() {
 
             if is_recursive_stack_references {
                 let r = refs.pop().unwrap();
-                eprintln!("ref = {:p}", r as *const u8);
                 if sp != 0 {
                     assert!(r > sp);
                     if let Some(child_ref) = child_ref {