--native-pointer-abi + --shadow-stack-size refuses wit-bindgen buffer node: inline linmem statics not down-shifted into .data (VCR-MEM-001 layer-2) #678

Summary

Dissolving a Component-Model composed node that carries buffers (wit-bindgen list<u8> across the seam — gale's gust:os syscall seam, the log capability) with --native-pointer-abi --shadow-stack-size <N> refuses:

Error: --shadow-stack-size: a native-pointer static access addends 1049612 into the
[0, sp_init) reservation (not the region base, not retargeted into .data);
down-shifting inline statics is the deferred general case. Refusing rather than
mis-addressing. VCR-MEM-001/#383.

1049612 = 0x10004C = the standard wasm linmem base 0x100000 + 0x4C — a data-segment constant (the canonical-ABI glue / a list<u8> literal) accessed as an inline static, which the native-pointer path can retarget to __synth_wasm_data only for the region-base case, not this addend-into-reservation case.

Why it matters (gale)

This is the exact blocker for buffer-carrying gust:os capabilities on a tiny MCU. The all-scalar path is perfect: gale's drivers and the gust:os time interface (u64/u32 only) dissolve to 0 SRAM cleanly. But the moment an interface carries a buffer (log: func(msg: list<u8>), and later channel/io), the wit-bindgen canonical ABI puts data/realloc in linmem, and --native-pointer-abi --shadow-stack-size (the F100 8-KiB-budget path, #383) refuses. Without it, synth reserves the full linmem page (64 KiB) → RAM-prohibitive on an 8-KiB part.

So: scalar CM nodes fit 8 KiB today; buffer-carrying CM nodes need the inline-static down-shift (retarget addend-into-linmem statics into the re-based .data/region) to fit. Larger-SRAM targets (64 KiB M3, M4) are unaffected — this is specifically the tiny-node budget path.

Ask

Implement the deferred general case in VCR-MEM-001/#383: down-shift inline linmem statics (addend-into-[0, sp_init)) into the re-based .data/__synth_wasm_data region under --native-pointer-abi --shadow-stack-size, so a buffer-carrying dissolved node links into an 8-KiB part.

Repro

gale gust:os step-2 node: app (imports gust:os/time+log) wac-plugged with time+log providers → meld fuse --memory shared → loom inline → synth compile --target cortex-m3 --all-exports --relocatable --native-pointer-abi --shadow-stack-size 2048. Happy to share the fused .wasm.

Kill-criterion: the above compile emits an ET_REL .o whose .data+.bss + declared shadow budget fits 8 KiB, and a semihosting run logs the expected bytes.