jason hoerner 6f67025ccc Shader Compiler: Optimized version of CleanupUniformBufferCode, called during preprocessing. New version is 3.8x faster, producing a 19% overall speedup in ConditionalPreprocessShader. Processes the shader in a single pass, scanning for potential compound identifiers (symbol tokens connected by dots and optional whitespace), then checking if they match known uniform buffer members. A few optimizations improve the speed of checking if an identifier matches, including an early out based on identifier length and start character, followed by organizing uniform buffers and their members by length, requiring only a small subset of members to be tested. Parsing uniform buffer definitions was also optimized to avoid memory allocation. ...

Doesn't produce bit identical preprocessed output, as it compacts whitespace from compound identifiers before testing them, whereas the original implementation compacts whitespace after matching.  Compacting first makes testing more efficient and simpler, since it doesn't need to take into account whitespace.  For A/B validation, I did add temporary debug code that stored and reverted un-matched identifiers, mimicking the old behavior, and it was identical across the board.

#rnx
#rb dan.elksnitis chris.waters jason.nadro

[CL 28313553 by jason hoerner in ue5-main branch]

2023-09-28 07:08:47 -04:00

..

Private

Shader Compiler: Optimized version of CleanupUniformBufferCode, called during preprocessing. New version is 3.8x faster, producing a 19% overall speedup in ConditionalPreprocessShader. Processes the shader in a single pass, scanning for potential compound identifiers (symbol tokens connected by dots and optional whitespace), then checking if they match known uniform buffer members. A few optimizations improve the speed of checking if an identifier matches, including an early out based on identifier length and start character, followed by organizing uniform buffers and their members by length, requiring only a small subset of members to be tested. Parsing uniform buffer definitions was also optimized to avoid memory allocation.

2023-09-28 07:08:47 -04:00

Public

[shaders] add debug dump option to output "detailed" shader source, including the output of the preprocessing step unmodified, the stripped version used for hashing, and whatever the final source passed to the compiler is (can differ from the stripped version if further modifications are applied as part of the compile step). this is only done if the preprocessed job cache is enabled; otherwise (and if this cvar is disabled) the single output will either be the compiler-step-modified source if it exists, or the output of the preprocessing step.

2023-09-27 11:02:18 -04:00

ShaderCompilerCommon.Build.cs

[shaders]

2023-05-03 10:17:48 -04:00