v0.17.16 — MSL Backend Hardening

Fixed (MSL)

• 64-bit atomic capability validation (#79, PR #82, @besmpl) —
  msl.Compile now returns a descriptive error for 64-bit atomic operations
  that Metal cannot represent instead of emitting invalid intrinsics. Matching
  Rust Naga, result-discarded min/max in storage address space remain
  supported; loads, stores, full operations, result-producing min/max, and
  workgroup min/max are rejected.
• Swizzle of binary expression missing parentheses (#83) —
  writeSwizzle now wraps binary/select sub-expressions in parentheses,
  matching Rust naga's is_scoped=false semantics. Without this, C++ member
  access (.) bound tighter than arithmetic operators, causing
  mat * vec.xyz instead of (mat * vec).xyz — a type error that Metal
  compiler rejected. Discovered via g3d standard.wgsl shader on Apple M5.

MSL: function-scope workgroup variables (PR #77, @georgebuilds)

Fixed

• MSL workgroup vars at function-body scope — workgroup (threadgroup) variables
  are now declared inside the kernel function body instead of as entry-point parameters.
  The parameter form requires the host to call setThreadgroupMemoryLength:atIndex: before
  dispatch; our Pure Go Metal HAL does not, causing workgroup memory to silently no-op.
  Function-scope declarations are legal MSL, statically sized by the compiler, and need
  no host-side setup. Verified on Apple M3 Max with Metal 3.1 runtime (@lkmavi).

• MSL per-entry-point workgroup zero-init filtering — writeWorkgroupZeroInit now
  filters by entry-point usage (matching Rust naga), so only workgroup vars actually used
  by the entry point are declared and zeroed.

Changed

• CONTRIBUTING.md — snapshot test infrastructure docs: golden file naming convention
  (1:1 with Rust naga test suite), reference allow-list, adding new test shaders.
  Updated project structure and testing commands.

Quality gates

• TestRustReference: ALL PASS (100%)
• SPIR-V validation: 172/172 (100%)
• golangci-lint: 0 issues
• CI: 11/11 checks pass (Linux, macOS, Windows)
• Hardware verified: Apple M3 Max, Metal 3.1 (@lkmavi)

GLSL version-aware binding + UniformInfo reflection (BUG-GLES-005)

GLSL backend now provides full infrastructure for runtime binding fallback on GL < 4.2 drivers (e.g., WSL2 Mesa d3d12 with GL 4.1 / GLSL 410). Follows Rust wgpu-hal device.rs:438-461 pattern.

Added

• SupportsExplicitLocations() on Version — gates layout(binding=N) emission on GLSL >= 420 (desktop) or >= 310 (ES). Matches Rust naga mod.rs:213.
• UniformInfo struct — reflection data for uniform/storage blocks (block name, binding, storage flag). Populated during GLSL code generation.
• TranslationInfo.Uniforms — carries uniform block reflection to HAL for post-link glGetUniformBlockIndex/glUniformBlockBinding assignment.
• VersionES300 constant — safe minimum for OpenGL ES contexts.

Fixed

• CI: Codecov OIDC migration — replaced CODECOV_TOKEN secret with OIDC token exchange, fixing GPG signature verification failures.

Quality gates

• TestRustReference: ALL PASS (100%)
• SPIR-V validation: 172/172 (100%)
• golangci-lint: 0 issues
• CI: 10/10 checks pass (Linux, macOS, Windows)

Fixed (DXIL)

• PHI node ordering — Vello path_count.wgsl now passes IDxcValidator. mem2reg Phase B phi instructions grouped at top of basic blocks.

Added

• Coverage waves 3-4: hlsl 70.6%, wgsl/lower 65.3%, msl 64.2%, spirv 76.5%, dxil/emit 37.4%

Metrics (unchanged)

• gg production: 61/61 (100%)
• IDxcValidator: 161/170 (94.7%)
• DXC golden diff=0: 105 (55.1%)

Enterprise Architecture Refactoring (ARCH-001)

All backends restructured following DXIL internal package pattern.

Internal packages (DXIL pattern applied to all backends)

• glsl/, msl/, hlsl/, spirv/ → internal/codegen/
• wgsl/ → internal/parser/ + internal/lower/
• Shared: internal/textutil/ (IndentWriter DRY), internal/backend/ (namer, sig packing), internal/registry/ (type dedup)
• Public API: real types, not aliases. go doc shows full struct definitions.

Test coverage (12/18 packages ≥80%)

Error handling

• 13 panics → error returns across all backends
• 2 nilerr fixes (spirv silently swallowed errors)
• Unsupported stage validation (mesh/task → clear error)
• 11 dead functions removed (-929 LOC)

Metrics (unchanged)

• gg production: 61/61 (100%)
• DXC golden diff=0: 105 (55.1% parity)
• IDxcValidator: 161/170 (94.7%)
• golangci-lint: 0 issues

gg Production: 61/61 VALID (100%) 🏆

Zero DXIL validation failures across all gg production entry points.

Fixed

• Array-of-vector flattening (BUG-DXIL-041) — fine.wgsl "Invalid record" caused by 3 bugs in flattened array<vec4<f32>, N> locals: GEP index not scaled by vector width, single-scalar load instead of multi-scalar, garbage component IDs.

• All golangci-lint issues resolved — extracted goconst constants, removed unused nolint directives, excluded keyword maps and tmp/ from lint.

Metrics

DXIL Architecture Push

Architectural improvements

• Workgroup struct decomposition — per-member globals with MSVC-mangled names
• ViewID ExprAlias/ExprPhi — precise post-mem2reg dataflow
• StmtEmit range merging — cross-range reassociation
• Instruction scheduling infrastructure — eval-right-first, resource read detection

Optimizations

• Constant folding (int-to-float casts, bitcast float→i32)
• Alignment encoding fix (log2+1)
• Mul-to-shl in CBV/UAV paths
• TBAA normalizer

DXIL Parity Push: 104 golden diff=0, 54.5% line parity

Crossed 100 diff=0 and 50% parity milestones. +10 diff=0 shaders, +6.4pp parity.

New optimizations

Bug fixes

Metrics

Note: DXIL backend is experimental.

WGSL Validation Hardening — 8 spec-compliance fixes

All 8 fixes independently verified against Rust naga — identical rejection behavior.

Fixes

35+ new unit tests. Reported by @maxsupermanhd (#66).

Fixed

• Function call argument type validation (#66).
  WGSL lowerer now validates argument count and types against function
  parameters. Passing vec2<u32> where u32 is expected now produces a
  clear compile error instead of silently generating invalid shader code
  that crashes at pipeline creation. Reported by @maxsupermanhd.

9 test cases covering shape mismatches, count mismatches, and abstract type concretization.