A side library of every vertex shader with stage inputs, as <key>_bv is, whose main0 / main0_z have no [[stage_in]] and read their inputs from a per-draw layout block at buffer 16: per stream the base address, stride and divisor, per NVN attribute its state word, the base instance from [[base_instance]] (so indirect draws are right too). dm_fetch decodes the NVN format at run time into the register words Maxwell's fetch gives the shader, and the input takes them with as_type, so the body runs unchanged. A pipeline built with it has no vertex descriptor and serves every vertex layout the pair is drawn with; the hybrid pipelines (next change) draw with it while a draw's own pipeline is built.
The words are bit-identical to Metal's vertex-descriptor fetch for every format nvn_mtl.m vfmt knows and to the host's CPU conversion for the integer-read-as-float formats: unorm / snorm through the unpack builtins (a plain division under fast math is a unit in the last place off for up to half the values), R11G11B10F NaNs canonical as from Metal, divisors with Metal's rule base + (instance - base) / divisor. Positions are [[invariant]] and built with preserved invariance, so a pulling pipeline and the vertex-descriptor one compute the same positions. Transform feedback, geometry capture and layer entries get no variant; shaders without stage inputs need none. The run-time decode costs GPU time: +65 % of a vertex-bound draw with 8 attributes on an M2 Max, about 1 ms per million vertices, so it is meant only to bridge the frames until the draw's own pipeline is built.
The iOS app does not use the variants yet (the Metal 4 path is off on iOS by default), so build_ipa.sh leaves the _bp libraries out of the IPA unless IOS_PULL=1 (pack_ipa.py --skip-suffix).
Chain version 8393d85a4eae (on main's 20fe3d62b9f6). Breath of the Wild's full Mac build on chain 97e2f301eb73 (25 min, a full retranslation since the code fingerprint changed): 19,592 shaders ok, 8,888 pulling libraries generated (275 MB), none failed, 43 vertex shaders without stage inputs; every existing library is byte-identical to the previous build (19,592 _b.metallib and _b.metal, 6,254 _bf, 1,070 _bv). Other profiles' shaders were not rebuilt.
Tests: t_pull.m (304 checks: the 76 formats vfmt knows, 73 comparisons with Metal's fetch at aligned, 2-byte and stride-1 placements, 24 with the CPU conversion, stride 0 and divisors 1-3 with a base instance), t_pull_inv.m (2,000 random triangles: a depth prepass with one pipeline and depth-equal with the other passes every covered pixel, both ways round) and test_dmsh_pull.py (the generator: entries, ids it adds or keeps, entries left out, shaders declined; compiles for macOS and iOS); pack_ipa.py's --skip-suffix checked by hand. The other graphics tests and the host unit tests give the results they give on main. docs/reference/rendering.md ("Pulling vertex inputs") describes the variant and its cost; AGENTS.md lists the new chain files.
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