[llvm] [CodeGen][StaticDataPartitioning]Place local-linkage global variables in hot or unlikely prefixed sections based on profile information (PR #125756)

[Snehasish Kumar via llvm-commits]

================
@@ -0,0 +1,198 @@
+; The static-data-splitter processes data from @cold_func first,
+; @unprofiled_func secondly, and @hot_func after the two functions above.
+; Tests that data hotness is based on aggregated module-wide profile
+; information. This way linker-mergable data is emitted once per module.
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; The three RUN commands set `-relocation-model=pic` so `hot_relro_array` and
+; `cold_relro_array` are placed in the .data.rel.ro-prefixed section.
+
+; This RUN command sets `-data-sections=true -unique-section-names=true` so data
+; sections are uniqufied by numbers.
+; RUN: llc -mtriple=x86_64-unknown-linux-gnu -enable-split-machine-functions \
----------------
snehasish wrote:

Reminder to update this test too once we remove the dependence on -enable-split-machine-functions.

https://github.com/llvm/llvm-project/pull/125756