Tess Strickland
953b1a9b0b
Both the regular and deferred versions of this test contain up to six different test cases: All platforms: * ELF snapshot, using DWARF from the snapshot * ELF snapshot, using DWARF from the separate debugging information For platforms where the test can assemble snapshots: * assembled snapshot, using DWARF from the snapshot or the separate .dSYM package on MacOS * assembled snapshot, using DWARF from the separate debugging information For MacOS only: * creating a single-architecture universal binary from the separate .dSYM package and extracting DWARF information from it * creating a multi-architecture universal binary from the separate .dSYM package and extracting DWARF information from it Originally the tests were written using package:expect, performing program compilation and execution separately before each test and lazily reading DWARF information within the test itself. Since tests using package:expect stop the program immediately on a failure, a failing expectation keeps other independent test cases from being checked. However, it's useful to know if the failure is limited to only a subset of the test cases, since that helps point at which code is to blame for the test failure(s). Now the tests are refactored to first set up the tests by performing all program compilation and execution first, collecting all outputs and DWARF information as test state. Then the test cases are defined over the collected test state using package:test instead of package:expect. This way, as long as there is not a failure in the initial setup, all of the applicable test cases are run even if one or more of them fail. ----- In pkg/native_stack_traces, changes the return types of the reader retrieval methods in the DwarfContainer class and DwarfSnapshot.fromDwarfContainer to be nullable. If the shared object does not contain the expected DWARF information, these methods now return null instead of causing null check exceptions to be thrown. Issue: https://github.com/dart-lang/sdk/issues/55612 Change-Id: I253965a95894f455e51d021e32dbf2703d8b99cf Cq-Include-Trybots: luci.dart.try:vm-aot-dwarf-linux-product-x64-try,vm-aot-linux-debug-x64-try,vm-aot-mac-release-arm64-try,vm-aot-mac-product-arm64-try,vm-aot-mac-release-x64-try,vm-aot-win-debug-arm64-try,vm-aot-win-debug-x64-try Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/375240 Commit-Queue: Tess Strickland <sstrickl@google.com> Reviewed-by: Daco Harkes <dacoharkes@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.