Handle reset vector not pointing to ELF symbol

Closes #391

CHANGELOG.md

@@ -7,8 +7,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/) and this p
 ## [Unreleased]
 
 - [#399] Update link shown in error message
+- [#398] Handle reset vector not pointing to ELF symbol
 
 [#399]: https://github.com/knurling-rs/probe-run/pull/399
+[#398]: https://github.com/knurling-rs/probe-run/pull/398
 
 ## [v0.3.8] - 2023-04-12
 

src/backtrace/unwind.rs

@@ -98,8 +98,11 @@ pub fn target(core: &mut Core, elf: &Elf, target_info: &TargetInfo) -> Output {
         // If the frame didn't move, and the program counter didn't change, bail out
         // (otherwise we might print the same frame over and over).
         if !cfa_changed && !program_counter_changed {
-            // If we do not end up in the reset function the stack is corrupted
-            output.corrupted = !elf.reset_fn_range().contains(&pc);
+            // If we do not end up in the reset function the stack is corrupted.
+            // If reset_fn_range is empty, we can't detect this and just assume that
+            // the stack was not corrupted.
+            let reset_fn_range = elf.reset_fn_range();
+            output.corrupted = !(reset_fn_range.contains(&pc) || reset_fn_range.is_empty());
             break;
         }
 

src/elf.rs

@@ -216,13 +216,16 @@ fn extract_symbols(elf: &ObjectFile, reset_fn_address: u32) -> anyhow::Result<Sy
 
     let main_fn_address = main_fn_address.ok_or(anyhow!("`main` symbol not found"))?;
     let reset_fn_range = {
-        let reset = match reset_symbols.len() {
-            1 => reset_symbols.remove(0),
-            _ => bail!("unable to determine reset handler"),
-        };
-        let addr = reset.address().try_into().expect("expected 32-bit ELF");
-        let size: u32 = reset.size().try_into().expect("expected 32-bit ELF");
-        addr..addr + size
+        if reset_symbols.len() == 1 {
+            let reset = reset_symbols.remove(0);
+            let addr = reset.address().try_into().expect("expected 32-bit ELF");
+            let size: u32 = reset.size().try_into().expect("expected 32-bit ELF");
+            addr..addr + size
+        } else {
+            log::debug!("unable to determine reset handler");
+            // The length of the reset handler is not known as it's not part of the ELF file
+            reset_fn_address..reset_fn_address
+        }
     };
 
     Ok(Symbols {