kc3-lang/angle

2024-10-31T14:22:31

Metal: Fix rewritten array variables clashes It was possible to generate MSL name clashes by declaring arrays, such as in: mat3 a[1] mat2 a_0; Complex GLSL outputs need to be linearized into primitive MSL types. This would happen for struct outputs, arrays and matrices. For these new MSL variables, the translator needs to invent new names that match, generated from both VS and FS. The clashes were due to the encoding scheme: For arrays, the MSL vertex output variable was named with _0 suffix for the array and _0 for the matrix row 0. In the example above, this would create a clash since also non-array mat would be linearized row-wise. For structs, field `a.b` would be encoded as `a_b`. By selecting different a and b, clashes could be generated trivially. It is redundant to encode named semantics in the out variable names. The only needed element is the discriminator which associates VS variables to FS variables. Currently this is done by using the user-provided root field name. Fix by encoding only the root variable name to the MSL variable name. The rest of the field discriminators are just a running number. Each GLSL name `a` is unique. MSL names get fixed suffix form `a_X`, and thus all of them are unique too. This is a continuation of following fixes that turned out to be incomplete: 6fe8a399dd Metal: Fix rewritten out variables with underscores 27423bffff Metal: Generate names for rewritten inputs Bug: angleproject:376417347 Change-Id: I407db373d201b3e321c6d8414bafdbecfd82cf19 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5979774 Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Commit-Queue: Kimmo Kinnunen <kkinnunen@apple.com>