[NFCI][StaticDataLayout] Introduce an LLVM option to control the emission of .hot data section prefix.

[mingmingl-llvm]

• Description:

  • This change introduces a new boolean LLVM option, -preserve-hot-data-section-prefix, which allows for disabling the .hot prefix for data sections in the intermediate object files (i.e., linker input files). The option defaults to true to maintain existing behavior.

• Context:

  • [lld][ELF] Introduce an option to keep data section prefix. #148985 extends lld -keep-data-section-prefix to map input sections to output sections based on hotness. When the option is enabled and linker input files have three kinds of rodata sections (.rodata, .rodata.hot, .rodata.unlikely), the executable will also have three kinds of sections. OTOH, to have simpler executable and more important to avoid unstudied performance penalty from segregated hot and lukewarm data , we'd prefer to have an .rodata.unlikely to group the cold data, and keep the rest (hot or lukewarm) in .rodata section.