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

[Ellis Hoag via llvm-commits]

================
@@ -0,0 +1,269 @@
+# 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
+
+# STARTUP: Ordered 3 sections using balanced partitioning
+
+# RUN: ld.lld -e main -o - a.o --irpgo-profile=a.profdata --bp-startup-sort=function --symbol-ordering-file a.orderfile | llvm-nm --numeric-sort --format=just-symbols - | FileCheck %s --check-prefix=ORDERFILE
+
+# ORDERFILE: _Z1Av
+# ORDERFILE: _Z1Fi
+# ORDERFILE: _Z1Ei
+# ORDERFILE: _Z1Di
+# ORDERFILE: _Z1Ci
+# ORDERFILE: _Z1Bi
+# ORDERFILE: main
+# ORDERFILE: r1
+# ORDERFILE: r2
+
+# RUN: ld.lld -e main -o a.out a.o --verbose-bp-section-orderer --bp-compression-sort=function 2>&1 | FileCheck %s --check-prefix=COMPRESSION-FUNC
+# RUN: ld.lld -e main -o a.out a.o --verbose-bp-section-orderer --bp-compression-sort=data 2>&1 | FileCheck %s --check-prefix=COMPRESSION-DATA
+# RUN: ld.lld -e main -o a.out a.o --verbose-bp-section-orderer --bp-compression-sort=both 2>&1 | FileCheck %s --check-prefix=COMPRESSION-BOTH
+# RUN: ld.lld -e main -o a.out a.o --verbose-bp-section-orderer --bp-compression-sort=both --irpgo-profile=a.profdata --bp-startup-sort=function 2>&1 | FileCheck %s --check-prefix=COMPRESSION-BOTH
+
+# COMPRESSION-FUNC: Ordered 7 sections using balanced partitioning
+# COMPRESSION-DATA: Ordered 3 sections using balanced partitioning
+# COMPRESSION-BOTH: Ordered 10 sections using balanced partitioning
+
+#--- a.proftext
+:ir
+:temporal_prof_traces
+# Num Traces
+1
+# Trace Stream Size:
+1
+# Weight
+1
+_Z1Av, _Z1Bi, _Z1Ci
+
+_Z1Av
+# Func Hash:
+1111
+# Num Counters:
+1
+# Counter Values:
+1
+
+_Z1Bi
+# Func Hash:
+2222
+# Num Counters:
+1
+# Counter Values:
+1
+
+_Z1Ci
+# Func Hash:
+3333
+# Num Counters:
+1
+# Counter Values:
+1
+
+_Z1Di
+# Func Hash:
+4444
+# Num Counters:
+1
+# Counter Values:
+1
+
+#--- a.orderfile
+_Z1Av
+_Z1Fi
+_Z1Ei
+_Z1Di
+
+#--- a.cc
----------------
ellishg wrote:

If you change this to a C file, you won't have to deal with mangled names.

```suggestion
#--- a.c
```

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