feat(LLVM): use no-opt for extremely large functions

[marxin]

I collected statistics for all our current Python WA modules where the change helps to reduce the compilation outliers. The total build of all the modules shrinks from 600s to 200s. The selected function threshold (100KB of LLVM IR) was selected based on the following numbers:

┌─────────────────────────────────────────────────────────────────────────────────┬───────────────────────┬─────────────────┬────────────────┬────────────┬───────────────┐
│ Function                                                                        │   LLVM IR size (in B) │   Before (in s) │   After (in s) │   x faster │ Note          │
├─────────────────────────────────────────────────────────────────────────────────┼───────────────────────┼─────────────────┼────────────────┼────────────┼───────────────┤
│ <module>:function_810                                                           │                191932 │          111.63 │           1    │      111.6 │ after is <1 s │
│ <module>:function_365                                                           │                518749 │           48.63 │           1.43 │       34   │               │
│ <module>:function_9039                                                          │                464830 │           48.08 │           2.86 │       16.8 │               │
│ <module>:function_5166                                                          │                468479 │           43.58 │           6.94 │        6.3 │               │
│ <module>:function_177                                                           │                404727 │           31.35 │           1.07 │       29.3 │               │
│ <module>:function_12519                                                         │                443508 │           29.63 │           8.8  │        3.4 │               │
│ <module>:function_311                                                           │                235271 │           29.22 │           1    │       29.2 │ after is <1 s │
│ <module>:function_22880                                                         │                313023 │           25.17 │           6.92 │        3.6 │               │
│ <module>:function_20346                                                         │                227496 │           24.12 │           7    │        3.4 │               │
│ libpq.so.5:__wasm_apply_data_relocs                                             │                340545 │           19.67 │           1    │       19.7 │ after is <1 s │
│ <module>:function_336                                                           │                247915 │           13.62 │           1    │       13.6 │ after is <1 s │
│ <module>:function_22552                                                         │                169301 │           11.8  │           3.16 │        3.7 │               │
│ <module>:function_1183                                                          │                194823 │           10.35 │           1    │       10.3 │ after is <1 s │
│ <module>:function_808                                                           │                387141 │            9.34 │           1.54 │        6.1 │               │
│ <module>:function_17074                                                         │                127432 │            8.71 │           2.76 │        3.2 │               │
│ <module>:function_139                                                           │                179688 │            7.07 │           1    │        7.1 │ after is <1 s │
│ <module>:function_812                                                           │                179498 │            6.61 │           1    │        6.6 │ after is <1 s │
│ <module>:function_23605                                                         │                 84627 │            6.49 │           4.83 │        1.3 │               │
│ <module>:function_22322                                                         │                 90254 │            6.11 │           4.93 │        1.2 │               │
│ loop.cpython-313-wasm32-wasi.so:__pyx_pymod_exec_loop                           │                145683 │            6.02 │           1    │        6   │ after is <1 s │
│ <module>:function_21507                                                         │                115251 │            5.87 │           1.9  │        3.1 │               │
│ offsets.cpython-313-wasm32-wasi.so:__Pyx_CreateStringTabAndInitStrings          │                 41411 │            4.86 │           4.95 │        1   │               │
│ <module>:function_218                                                           │                 38860 │            4.64 │           4.64 │        1   │               │
│ <module>:function_21167                                                         │                 60100 │            4.6  │           3.97 │        1.2 │               │
│ <module>:function_17626                                                         │                 60179 │            3.52 │           2.4  │        1.5 │               │
│ hashtable.cpython-313-wasm32-wasi.so:__Pyx_CreateStringTabAndInitStrings        │                 34755 │            3.41 │           3.45 │        1   │               │
│ <module>:function_9037                                                          │                140197 │            3.32 │           1    │        3.3 │ after is <1 s │
│ groupby.cpython-313-wasm32-wasi.so:__pyx_pymod_exec_groupby                     │                115042 │            3.23 │           1    │        3.2 │ after is <1 s │
│ _generator.cpython-313-wasm32-wasi.so:__Pyx_CreateStringTabAndInitStrings       │                 33293 │            3.18 │           3.21 │        1   │               │
│ <module>:function_695                                                           │                109653 │            2.83 │           1    │        2.8 │ after is <1 s │
│ <module>:function_18038                                                         │                145429 │            2.62 │           1    │        2.6 │ after is <1 s │
│ lib.cpython-313-wasm32-wasi.so:__Pyx_CreateStringTabAndInitStrings              │                 30045 │            2.59 │           2.6  │        1   │               │
│ mtrand.cpython-313-wasm32-wasi.so:__Pyx_CreateStringTabAndInitStrings           │                 28927 │            2.45 │           2.47 │        1   │               │
│ timestamps.cpython-313-wasm32-wasi.so:__Pyx_CreateStringTabAndInitStrings       │                 28346 │            2.45 │           2.45 │        1   │               │
│ etree.cpython-313-wasm32-wasi.so:__pyx_pymod_exec_etree                         │                132010 │            2.38 │           1    │        2.4 │ after is <1 s │
│ <module>:function_21626                                                         │                 45890 │            2.2  │           2.28 │        1   │               │
│ etree.cpython-313-wasm32-wasi.so:__wasm_apply_data_relocs                       │                 91676 │            2.17 │           2.51 │        0.9 │               │
│ timedeltas.cpython-313-wasm32-wasi.so:__Pyx_CreateStringTabAndInitStrings       │                 26355 │            2.08 │           2.08 │        1   │               │
│ <module>:function_1678                                                          │                 34104 │            2.06 │           1.99 │        1   │               │
│ <module>:function_197                                                           │                 69549 │            1.94 │           2.07 │        0.9 │               │
│ <module>:function_18505                                                         │                 47317 │            1.85 │           1.75 │        1.1 │               │
│ _multiarray_umath.cpython-313-wasm32-wasi.so:__wasm_apply_data_relocs           │                 74951 │            1.76 │           1.91 │        0.9 │               │
│ _multiarray_umath.cpython-313-wasm32-wasi.so:__wasm_apply_data_relocs           │                 76106 │            1.76 │           1.99 │        0.9 │               │
│ <module>:function_2070                                                          │                136716 │            1.75 │           1    │        1.8 │ after is <1 s │
│ hashtable.cpython-313-wasm32-wasi.so:__pyx_pymod_exec_hashtable                 │                161367 │            1.58 │           1    │        1.6 │ after is <1 s │
│ index.cpython-313-wasm32-wasi.so:__Pyx_CreateStringTabAndInitStrings            │                 22482 │            1.48 │           1.44 │        1   │               │
│ <module>:function_19449                                                         │                 30969 │            1.45 │           1.32 │        1.1 │               │
│ period.cpython-313-wasm32-wasi.so:__Pyx_CreateStringTabAndInitStrings           │                 21974 │            1.44 │           1.41 │        1   │               │
│ algos.cpython-313-wasm32-wasi.so:__Pyx_CreateStringTabAndInitStrings            │                 22552 │            1.44 │           1.55 │        0.9 │               │
│ _write.cpython-313-wasm32-wasi.so:__pyx_pymod_exec__write                       │                 61709 │            1.43 │           1.53 │        0.9 │               │
│ <module>:function_252                                                           │                 20719 │            1.38 │           1.37 │        1   │               │
│ <module>:function_7717                                                          │                 77908 │            1.38 │           1.43 │        1   │               │
│ <module>:function_21490                                                         │                 29077 │            1.37 │           1.16 │        1.2 │               │
│ <module>:function_17019                                                         │                 30498 │            1.35 │           1.29 │        1   │               │
│ parsers.cpython-313-wasm32-wasi.so:__Pyx_CreateStringTabAndInitStrings          │                 20742 │            1.3  │           1.3  │        1   │               │
│ <module>:function_22505                                                         │                 28464 │            1.27 │           1.1  │        1.2 │               │
│ <module>:function_18467                                                         │                 52383 │            1.21 │           1    │        1.2 │ after is <1 s │
│ __init__.cpython-313-wasm32-wasi.so:add_apsw_constants                          │                 31287 │            1.19 │           1.23 │        1   │               │
│ corecext.cpython-313-wasm32-wasi.so:__pyx_pymod_exec_corecext                   │                 52555 │            1.19 │           1.19 │        1   │               │
│ dtypes.cpython-313-wasm32-wasi.so:__Pyx_CreateStringTabAndInitStrings           │                 19827 │            1.17 │           1.15 │        1   │               │
│ _sqlite_ext.cpython-313-wasm32-wasi.so:__pyx_pymod_exec__sqlite_ext             │                 37829 │            1.16 │           1.15 │        1   │               │
│ <module>:function_12304                                                         │                 55745 │            1.14 │           1.1  │        1   │               │
│ <module>:function_23392                                                         │                 27160 │            1.13 │           1    │        1.1 │ after is <1 s │
│ <module>:function_14405                                                         │                 29056 │            1.13 │           1    │        1.1 │ after is <1 s │
│ <module>:function_18023                                                         │                 24761 │            1.09 │           1    │        1.1 │ after is <1 s │
│ aggregations.cpython-313-wasm32-wasi.so:__pyx_pymod_exec_aggregations(_object*) │                 35550 │            1.07 │           1.12 │        1   │               │
│ algos.cpython-313-wasm32-wasi.so:__pyx_pymod_exec_algos                         │                111592 │            1.07 │           1    │        1.1 │ after is <1 s │
│ <module>:function_28130                                                         │                 36104 │            1.07 │           1    │        1.1 │ after is <1 s │
│ _http_parser.cpython-313-wasm32-wasi.so:__pyx_pymod_exec__http_parser           │                 95902 │            1.06 │           1.15 │        0.9 │               │
│ <module>:function_15118                                                         │                 21743 │            1.04 │           1    │        1   │ after is <1 s │
│ parsing.cpython-313-wasm32-wasi.so:__Pyx_CreateStringTabAndInitStrings          │                 18431 │            1.03 │           1    │        1   │ after is <1 s │
│ nattype.cpython-313-wasm32-wasi.so:__pyx_pymod_exec_nattype                     │                 51922 │            1.02 │           1.05 │        1   │               │
│ <module>:function_26195                                                         │                 28699 │            1.02 │           1    │        1   │ after is <1 s │
│ interval.cpython-313-wasm32-wasi.so:__Pyx_CreateStringTabAndInitStrings         │                 18594 │            1    │           1.01 │        1   │               │
└─────────────────────────────────────────────────────────────────────────────────┴───────────────────────┴─────────────────┴────────────────┴────────────┴───────────────┘

[Copilot]

Pull request overview

This PR introduces a compile-time optimization that selectively disables LLVM optimizations for extremely large functions (>100KB of LLVM IR). This reduces total build time from 600s to 200s by avoiding expensive optimization passes on functions where the optimization overhead outweighs the runtime benefits.

Key Changes:

• Added optional unoptimized target machine to FuncTranslator for handling large functions
• Introduced target_machine_with_opt() method to create target machines with configurable optimization levels
• Implemented size-based threshold (100KB) to switch between optimized and unoptimized compilation

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 6 comments.

File	Description
lib/compiler-llvm/src/translator/code.rs	Added optional unoptimized target machine field and logic to select between optimized/unoptimized compilation based on function size
lib/compiler-llvm/src/config.rs	Added target_machine_with_opt() method to create target machines with configurable optimization levels
lib/compiler-llvm/src/compiler.rs	Updated FuncTranslator initialization in parallel compilation path to pass both optimized and unoptimized target machines

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Arshia001]

• zen mode activated *

[syrusakbary]

What is the speed difference when running Python? Also, can we have just some passes but detect which one is actually slowing things down? (rather than just have 0 passes)

[marxin]

What is the speed difference when running Python? Also, can we have just some passes but detect which one is actually slowing things down?

On my AMD 12-core Zen machine, python/python goes from 92s to 10s. One my Framework laptop, it's 135s -> 30s.

My expectation is the outliers are so huge that there will be multiple LLVM passes struggling. Should I create an issue and address it in a more detail?

[marxin]

I've just checked the php-benchmark-script and pystone and there's no change from the perspective of the benchmarks before and with the PR changes.

[syrusakbary]

My expectation is the outliers are so huge that there will be multiple LLVM passes struggling. Should I create an issue and address it in a more detail?

Yes, please

[marxin]

Yes, please

#6005