Tess Strickland
1f5fd27c61
The command line flag allows the user to specify the minimum MacOS or iOS version used in the build version load command for the Mach-O dynamic library snapshot. If not specified, the minimum OS version specified in macOS Mach-O snapshots is 10.15 (Catalina) and the minimum OS version specified in iOS Mach-O snapshots is 13. This CL also changes the targeted OS version in the build version load command to be the same as the minimum OS version. Adds support to parsing build version load commands to pkg/native_stack_traces's Mach-O parser in order to test the existence and contents of build version load commands in vm/dart/unobfuscated_static_symbols. TEST=vm/dart/unobfuscated_static_symbols Issue: https://github.com/dart-lang/sdk/issues/60307 Change-Id: I3ee3ba34297d3261be7e3a1d2fb3c1da1ef0ef05 Cq-Include-Trybots: luci.dart.try:vm-aot-mac-debug-x64-try,vm-aot-mac-debug-arm64-try,vm-aot-linux-debug-arm64-try,vm-aot-linux-debug-x64-try,pkg-mac-release-try,pkg-mac-release-arm64-try,pkg-linux-release-arm64-try Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/438901 Reviewed-by: Ryan Macnak <rmacnak@google.com> Commit-Queue: Tess Strickland <sstrickl@google.com>
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.
@pragma('vm:prefer-inline')
bar() => throw Null;
@pragma('vm:never-inline')
foo() => bar();
main() => foo();
Now we run the following commands:
# Make sure that we have the native_stack_traces package.
$ dart 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.
$ dart compile exe -S throws.debug throws.dart
# Run the program, saving the error output to throws.err.
$ ./throws.exe 2>throws.err
# Using the saved debugging information, we can translate the stack trace
# contained in throws.err to its symbolic form.
$ dart pub global run native_stack_traces:decode translate -d throws.debug -i throws.err
Features and bugs
Please file feature requests and bugs at the issue tracker.