# native_stack_traces 0.3.6

Utilities for working with non-symbolic stack traces.




## Installing
```
export PUB_HOSTED_URL=https://pub.mirror.p-hatan.ir
flutter pub add 'native_stack_traces:0.3.6'
```
Published: 2020-05-20T08:26:55.706413Z
Expected archive SHA-256: e53de20184736caac5783845c6fa0ae32cf44e096fd1210401fcccd266302093

Available in cache; verification: upstream_checksum
## Direct dependencies
- args: ^1.5.2
- path: ^1.6.4

## Package README (untrusted upstream documentation)
# native_stack_traces

This package provides libraries and a utility for decoding non-symbolic
stack traces generated by an AOT-compiled Dart application.

## Converting stack traces

In some modes of AOT compilation, information on mapping execution points to
source locations is no longer stored in the Dart image. Instead, this
information is translated to separately stored debugging information.
This debugging information can then be stripped from the application
before shipping.

However, there is a drawback. Stack traces generated by such an application no
longer includes file, function, and line number information (i.e., symbolic
stack traces). Instead, stack trace frames simply include program counter
information. Thus, to find the source information for these frames, we must use
the debugging information. This means either keeping the original unstripped
application, or saving the debugging information into a separate file.

Given this debugging information, the libraries in this package can turn
non-symbolic stack traces back into symbolic stack traces. In addition, this
package includes a command line tool `decode` whose output is the same as its
input except that non-symbolic stack traces are translated.

### Using `decode`

Take the following Dart code, which we put in `throws.dart`. The inlining
pragmas are here just to ensure that `bar` is inlined into `foo` and that `foo`
is _not_ inlined into `bar`, to illustrate how inlined code is handled in the
translated output.

```dart
@pragma('vm:prefer-inline')
bar() => throw null;

@pragma('vm:never-inline')
foo() => bar();

main() => foo();
```

Now we run the following commands:

```bash
# Make sure that we have the native_stack_traces package.
$ pub get native_stack_traces
$ pub global activate native_stack_traces

# We compile the example program, removing the source location information
# from the snapshot and saving the debugging information into throws.debug.
$ dart2native -k aot -S throws.debug -o throws.aotsnapshot throws.dart

# Run the program, saving the error output to throws.err.
$ dartaotruntime throws.aotsnapshot 2>throws.err

# Using the saved debugging information, we can translate the stack trace
# contained in throws.err to its symbolic form.
$ pub global run native_stack_traces:decode translate -d throws.debug -i throws.err

# We can also just pipe the output of running the program directly into
# the utility.
$ dartaotruntime throws.aotsnapshot |& \
    pub global run native_stack_traces:decode translate -d throws.debug
```

## Features and bugs

Please file feature requests and bugs at the [issue tracker][tracker].

[tracker]: https://github.com/dart-lang/sdk/issues

## Changelog
# Changelog

## 0.3.6

- Adjusts RegExp for stack trace header line to be more flexible in what it
  permits to allow additional information to be added in the Dart VM.

## 0.3.5

- Use virtual addresses in non-symbolic stack frames as a fallback if we cannot
  retrieve an appropriate offset from the instructions section otherwise.

## 0.3.4

- Decoded Dart calls are now never considered internal, only VM stub calls.
  This is due to a concurrent change in the Dart VM that no longer prints
  non-symbolic frames for functions considered invisible, which matches the
  symbolic frame printer and removes the need for the decoder to guess which
  frames should be hidden.

  This package still works on earlier versions of Dart, so the dependencies have
  not changed. However, it may print more frame information than expected when
  decoding stack frames from a Dart VM that does not include this change to
  non-symbolic stack printing.

## 0.3.3

- No externally visible changes.

## 0.3.2

- The `find` command can now look up addresses given as offsets from static
  symbols, not just hexadecimal virtual or absolute addresses.
- Integer inputs (addresses or offsets) without an '0x' prefix or hexadecimal
  digits will now be parsed as decimal unless the `-x`/`--force_hexadecimal`
  flag is used.

## 0.3.1

- Uses dynamic symbol information embedded in stack frame lines when available.

## 0.3.0

- Adds handling of virtual addresses within stub code payloads.

## 0.2.2

- Finds instruction sections by the dynamic symbols the Dart VM creates instead
  of assuming there are two text sections.

## 0.2.1

- Added static method `Dwarf.fromBuffer`.

## 0.2.0

- API and documentation cleanups

## 0.1.0

- Initial release