llvm-project

2a9afdb7 - [clang] Reduce the size of ParsedAttributesView and AttributePool (#148726)

[clang] Reduce the size of ParsedAttributesView and AttributePool (#148726) These objects are used as local stack variables during parsing, and they are not small. This patch reduces their sizes: * `ParsedAttributesView`: 72 → 40 bytes * `AttributePool`: 72 → 40 bytes No negative performance impact has been [observed](https://llvm-compile-time-tracker.com/compare.php?from=a709621cd545b061782b03136286227867b452a6&to=f50500b3c178e97c0c861301e853e6d5b859040b&stat=instructions:u). **Context:** We have some verilator-generated code with extremely deep nesting of parenthesized expressions, e.g.: ```cpp bool s = (...(bool)(i[0]) |(bool)(i[1])) |(bool)(i[2])) | ... |(bool)(i[n])); ``` Before this patch, on my local machine, Clang begins emitting `-Wstack-exhausted` when `n` is 715. After the patch, that threshold increases to `950`.