2513fbedca
Implementation of #137341 This adds support for using references to any variable in a local scope inside the shader codebase. Example: ```cpp int a = 0; int &b = a; b++; /* a == 1 */ ``` Using `auto` is supported for reference definition as the type is not preserved by the copy paste procedure. Type checking is done by the C++ shader compilation or after the copy paste procedure during shader compilation. `auto` is still unsupported for other variable declarations. Reference to opaque types (`image`, `sampler`) are supported since they are never really assigned to a temp variable. This implements all safety feature related to the implementation being copy pasting the definition string. That is: - No `--`, `++` operators. - No function calls. - Array subscript index needs to be int constants or constant variable. The copy pasting does not replace member access: `auto &a = b; a.a = c;` becomes `b.a = c;` The copy pasting does not replace function calls: `auto &a = b; a = a();` becomes `b = a();` While limited, this already allows for nicer syntax (aliasing) for accessing SSBOs and the potential overhead of a copy semantic: ```cpp ViewMatrices matrices = drw_view_buf[0]; matrices.viewmat = float4x4(1); drw_view_buf[0] = matrices; ``` Can now be written as; ```cpp ViewMatrices &matrices = drw_view_buf[0]; matrices.viewmat = float4x4(1); ``` Which expands to; ```cpp drw_view_buf[0].viewmat = float4x4(1); ``` Note that the reference semantic is not carried through function call because arguments are transformed to `inout` in GLSL. `inout` has copy semantic but it is often implemented as reference by some implementations. Another important note is that this copy-pasting doesn't check if a symbol is a variable. It can match a typename. But given that our typenames have different capitalizations style this is unlikely to be an issue. If that issue arise, we can add a check for it. Rel #137446 Pull Request: https://projects.blender.org/blender/blender/pulls/138412
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