[lld] [lld][ELF] Extend profile guided function ordering to ELF binaries (PR #117514)

[Ellis Hoag via llvm-commits]

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+# REQUIRES: aarch64
+
+# RUN: rm -rf %t && split-file %s %t && cd %t
+# RUN: llvm-mc -filetype=obj -triple=aarch64 a.s -o a.o
+# RUN: llvm-profdata merge a.proftext -o a.profdata
+# RUN: ld.lld -e main -o a.out a.o --irpgo-profile=a.profdata --bp-startup-sort=function --verbose-bp-section-orderer 2>&1 | FileCheck %s --check-prefix=STARTUP
+# RUN: ld.lld -e main -o a.out a.o --irpgo-profile=a.profdata --bp-startup-sort=function --verbose-bp-section-orderer --icf=all --bp-compression-sort=none 2>&1 | FileCheck %s --check-prefix=STARTUP
----------------
ellishg wrote:

`--bp-compression-sort=none` is already the default. In fact, these two lines are identical except for `--icf=all`. Do we need them both?
```suggestion
# RUN: ld.lld -e main -o a.out a.o --irpgo-profile=a.profdata --bp-startup-sort=function --verbose-bp-section-orderer 2>&1 | FileCheck %s --check-prefix=STARTUP
# RUN: ld.lld -e main -o a.out a.o --irpgo-profile=a.profdata --bp-startup-sort=function --verbose-bp-section-orderer --icf=all 2>&1 | FileCheck %s --check-prefix=STARTUP
```

https://github.com/llvm/llvm-project/pull/117514