Skip stack overflow handler for panic=immediate-abort #147090
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r? @ibraheemdev rustbot has assigned @ibraheemdev. Use |
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std installs guard pages and a signal handler to ensure that stackoverflows 1) terminate abruptly and 2) print an nice message. Even for panic=immediate-abort, 1) is desirable, we don't want silent data corruption there. But 2) is completely unnecessary, as users deliberately *don't* want nice messages, they want minimum binary size. Therefore, skip the entire guard signal handler setup, which saves a lot of bytes. I tested this with a hello world binary using fat LTO, build-std, panic=immediate-abort, opt-level=s, strip=debuginfo. `size` reports significant savings: ``` text data bss dec hex filename 15252 1032 104 16388 4004 tiny-before 6881 964 48 7893 1ed5 tiny-after2 ``` `nm -U` goes from 71 to 56, getting rid of a bunch of stack overflow related symbols. The disk size goes from `31k` to `24k`. The impact on the error message is minimal, as the message was already missing. before: ``` fish: Job 1, './tiny-so-before' terminated by signal SIGABRT (Abort) ``` after: ``` fish: Job 1, './tiny-so-after' terminated by signal SIGSEGV (Address boundary error) ```
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Makes sense! |
bors
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Sep 29, 2025
…oboet Skip stack overflow handler for panic=immediate-abort std installs guard pages and a signal handler to ensure that stackoverflows 1) terminate abruptly and 2) print an nice message. Even for panic=immediate-abort, 1) is desirable, we don't want silent data corruption there. But 2) is completely unnecessary, as users deli 8000 berately *don't* want nice messages, they want minimum binary size. Therefore, skip the entire guard signal handler setup, which saves a lot of bytes. I tested this with a hello world binary using fat LTO, build-std, panic=immediate-abort, opt-level=s, strip=debuginfo. `size` reports significant savings: ``` text data bss dec hex filename 15252 1032 104 16388 4004 tiny-before 6881 964 48 7893 1ed5 tiny-after2 ``` `nm -U` goes from 71 to 56, getting rid of a bunch of stack overflow related symbols. The disk size goes from `31k` to `24k`. The impact on the error message is minimal, as the message was already missing. before: ``` fish: Job 1, './tiny-so-before' terminated by signal SIGABRT (Abort) ``` after: ``` fish: Job 1, './tiny-so-after' terminated by signal SIGSEGV (Address boundary error) ``` I didn't test the Windows part, but it likely also has savings.
Zalathar
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Sep 29, 2025
…erflow, r=joboet Skip stack overflow handler for panic=immediate-abort std installs guard pages and a signal handler to ensure that stackoverflows 1) terminate abruptly and 2) print an nice message. Even for panic=immediate-abort, 1) is desirable, we don't want silent data corruption there. But 2) is completely unnecessary, as users deliberately *don't* want nice messages, they want minimum binary size. Therefore, skip the entire guard signal handler setup, which saves a lot of bytes. I tested this with a hello world binary using fat LTO, build-std, panic=immediate-abort, opt-level=s, strip=debuginfo. `size` reports significant savings: ``` text data bss dec hex filename 15252 1032 104 16388 4004 tiny-before 6881 964 48 7893 1ed5 tiny-after2 ``` `nm -U` goes from 71 to 56, getting rid of a bunch of stack overflow related symbols. The disk size goes from `31k` to `24k`. The impact on the error message is minimal, as the message was already missing. before: ``` fish: Job 1, './tiny-so-before' terminated by signal SIGABRT (Abort) ``` after: ``` fish: Job 1, './tiny-so-after' terminated by signal SIGSEGV (Address boundary error) ``` I didn't test the Windows part, but it likely also has savings.
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Yielding to enclosing rollup. @bors retry |
bors
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Sep 29, 2025
Rollup of 6 pull requests Successful merges: - #133477 (Detect tuple structs that are unconstructable due to re-export) - #140916 (Fix unuseful span in type error in some format_args!() invocations) - #146979 (constify Default on Nanoseconds) - #147090 (Skip stack overflow handler for panic=immediate-abort) - #147092 (Do not compute optimized MIR if code does not type-check.) - #147127 (Add a leading dash to linker plugin arguments in the gcc codegen) r? `@ghost` `@rustbot` modify labels: rollup
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☀️ Test successful - checks-actions |
What is this?This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.Comparing f957826 (parent) -> 772f380 (this PR) Test differencesShow 2 test diffs2 doctest diffs were found. These are ignored, as they are noisy. Test dashboardRun cargo run --manifest-path src/ci/citool/Cargo.toml -- \
test-dashboard 772f380092b30680313b70a622cafc17f03e6bff --output-dir test-dashboardAnd then open Job duration changes
How to interpret the job duration changes?Job durations can vary a lot, based on the actual runner instance |
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Finished benchmarking commit (772f380): comparison URL. Overall result: no relevant changes - no action needed@rustbot label: -perf-regression Instruction countThis benchmark run did not return any relevant results for this metric. Max RSS (memory usage)Results (primary 2.5%)A less reliable metric. May be of interest, but not used to determine the overall result above.
CyclesResults (primary -2.6%, secondary 0.6%)A less reliable metric. May be of interest, but not used to determine the overall result above.
Binary sizeThis benchmark run did not return any relevant results for this metric. Bootstrap: 470.189s -> 469.945s (-0.05%) |
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std installs guard pages and a signal handler to ensure that stackoverflows 1) terminate abruptly and 2) print an nice message. Even for panic=immediate-abort, 1) is desirable, we don't want silent data corruption there. But 2) is completely unnecessary, as users deliberately don't want nice messages, they want minimum binary size.
Therefore, skip the entire guard signal handler setup, which saves a lot of bytes.
I tested this with a hello world binary using fat LTO, build-std, panic=immediate-abort, opt-level=s, strip=debuginfo.
sizereports significant savings:nm -Ugoes from 71 to 56, getting rid of a bunch of stack overflow related symbols. The disk size goes from31kto24k.The impact on the error message is minimal, as the message was already
missing.
before:
after:
I didn't test the Windows part, but it likely also has savings.