Experimental: Replace pony_error() with error-flag returns#5002
Draft
SeanTAllen wants to merge 2 commits intomainfrom
Draft
Experimental: Replace pony_error() with error-flag returns#5002SeanTAllen wants to merge 2 commits intomainfrom
SeanTAllen wants to merge 2 commits intomainfrom
Conversation
Partial functions now return {T, i1} tuples (or i1 for void-returning
class constructors) where the i1 flag indicates whether an error
occurred. This eliminates C++ exception overhead for Pony error
handling while keeping C++ exceptions only for FFI calls where C code
may call pony_error().
The key changes:
- Partial Pony functions return error flags instead of unwinding.
Call sites check the flag and branch to error handlers or propagate.
- Try blocks use a dual mechanism: invoke_target for error-flag
branches from Pony calls, landing_pad for C++ exception unwind
from FFI invoke instructions.
- Bare functions (@{...}) are excluded — they keep pony_error()
semantics since C callers don't understand error flags.
- Vtable consistency: when a non-partial concrete method (e.g.
Cons.head()) shares a vtable index with a partial dispatch method
(e.g. List.head()), a thin wrapper is generated that calls the
concrete method and wraps the result with {value, false}.
- C runtime functions (socket.c, time.c) that previously called
pony_error() now return sentinel values (SIZE_MAX, NULL). The
corresponding Pony callers check for sentinels and raise errors.
Design: #4997
Closes #4443
ponylang-main
added
the
discuss during sync
Member
Author
|
This isnt actually ready for review. I switched it to that to get CI to run. |
SeanTAllen
removed
the
discuss during sync
ponylang-main
added
the
discuss during sync
With error-flag returns replacing C++ exceptions for Pony-to-Pony error propagation (previous commit), the exception infrastructure is dead code. Removes: pony_error(), pony_try(), ponyint_personality_v0(), LSDA scanning, the except_try_catch.ll LLVM IR, and all landing pad / invoke / personality machinery from codegen. Bare functions that hit `error` outside a try block now call abort() instead of pony_error(). This means bare partial lambdas can no longer propagate errors across C frames — the mechanism they relied on (C++ exceptions) no longer exists. The Pony serialise package is the only stdlib user of this pattern, so it is removed along with its tests. The C-level serialise runtime used internally by the compiler is unaffected. Renames invoke_target to error_target in compile_frame_t to reflect its post-Phase-3 role as a branch target for error-flag checks rather than an invoke unwind destination.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
This is an experimental/draft PR to test CI and enable performance testing. Do not merge.
Implements the error-flag return approach from #4997 (Discussion) to address #4443.
Partial Pony functions now return
{T, i1}tuples instead of using C++ exception unwinding. Thei1flag isfalsefor normal returns andtruefor errors. C++ exceptions are retained only for FFI calls where C runtime code callspony_error().Key implementation details:
{T, i1}(value-returning) ori1(void class constructors). Call sites check the flag and branch to error handlers or propagate.invoke_targetfor error-flag branches from Pony calls;landing_padfor C++ exception unwind from FFI invoke instructions.@{...}bare functions keeppony_error()semantics since C callers don't understand error flags.socket.candtime.cthat calledpony_error()now return sentinel values (SIZE_MAX,NULL). Pony callers check sentinels and raise errors.All 377 stdlib tests pass locally on Linux x86_64. This PR is to verify CI across all platforms and enable performance benchmarking before further work (Phase 4: dead exception infrastructure cleanup).