[llvm-branch-commits] [llvm] [BOLT] Use heuristic for matching split local functions (PR #90424)

[Amir Ayupov via llvm-branch-commits]

https://github.com/aaupov updated https://github.com/llvm/llvm-project/pull/90424

>From b9a8ff53a491f126fb0dcf8cc371ed7a053e859b Mon Sep 17 00:00:00 2001
From: Amir Ayupov <aaupov at fb.com>
Date: Mon, 29 Apr 2024 12:48:24 -0700
Subject: [PATCH 1/3] Revert cdsplit-symbol-names.s

---
 bolt/test/X86/cdsplit-symbol-names.s | 24 ++++--------------------
 1 file changed, 4 insertions(+), 20 deletions(-)

diff --git a/bolt/test/X86/cdsplit-symbol-names.s b/bolt/test/X86/cdsplit-symbol-names.s
index 0d9149f49db908..e53863e22246d6 100644
--- a/bolt/test/X86/cdsplit-symbol-names.s
+++ b/bolt/test/X86/cdsplit-symbol-names.s
@@ -2,14 +2,12 @@
 # Warm section should have name .text.warm and warm function fragments should
 # have symbol names ending in warm.
 
-# RUN: split-file %s %t
-# RUN: llvm-mc --filetype=obj --triple x86_64-unknown-unknown %t/main.s -o %t.o
-# RUN: llvm-mc --filetype=obj --triple x86_64-unknown-unknown %t/chain.s -o %t.chain.o
+# RUN: llvm-mc --filetype=obj --triple x86_64-unknown-unknown %s -o %t.o
 # RUN: link_fdata %s %t.o %t.fdata
 # RUN: llvm-strip --strip-unneeded %t.o
-# RUN: %clang %cflags %t.o %t.chain.o -o %t.exe -Wl,-q
+# RUN: %clang %cflags %t.o -o %t.exe -Wl,-q
 # RUN: llvm-bolt %t.exe -o %t.bolt --split-functions --split-strategy=cdsplit \
-# RUN:   --call-scale=2 --data=%t.fdata --reorder-blocks=ext-tsp --enable-bat
+# RUN:         --call-scale=2 --data=%t.fdata --reorder-blocks=ext-tsp
 # RUN: llvm-objdump --syms %t.bolt | FileCheck %s --check-prefix=CHECK-SYMS-WARM
 
 # CHECK-SYMS-WARM: 0000000000000000 l df *ABS* 0000000000000000 bolt-pseudo.o
@@ -18,22 +16,8 @@
 # CHECK-SYMS-WARM: .text.cold
 # CHECK-SYMS-WARM-SAME: dummy.cold
 
-# RUN: link_fdata %s %t.bolt %t.preagg PREAGG
-# PREAGG: B X:0 #chain.warm# 1 0
-# RUN: perf2bolt %t.bolt -p %t.preagg --pa -o %t.bat.fdata -w %t.bat.yaml -v=1 \
-# RUN:   | FileCheck %s --check-prefix=CHECK-REGISTER
-
-# CHECK-REGISTER: BOLT-INFO: marking chain.warm/1(*2) as a fragment of chain/2(*2)
-
-#--- chain.s
-        .text
-        .type   chain, @function
-chain:
-        ret
-        .size   chain, .-chain
-
-#--- main.s
         .text
+        .globl  chain
         .type   chain, @function
 chain:
         pushq   %rbp

>From 7c92aca6a0cba71bfde9eb2127575d93e210d346 Mon Sep 17 00:00:00 2001
From: Amir Ayupov <aaupov at fb.com>
Date: Mon, 29 Apr 2024 12:48:39 -0700
Subject: [PATCH 2/3] Add register-fragments-bolt-symbols.s

---
 .../X86/register-fragments-bolt-symbols.s     | 32 +++++++++++++++++++
 1 file changed, 32 insertions(+)
 create mode 100644 bolt/test/X86/register-fragments-bolt-symbols.s

diff --git a/bolt/test/X86/register-fragments-bolt-symbols.s b/bolt/test/X86/register-fragments-bolt-symbols.s
new file mode 100644
index 00000000000000..fa9b70e0b2d891
--- /dev/null
+++ b/bolt/test/X86/register-fragments-bolt-symbols.s
@@ -0,0 +1,32 @@
+# Test the heuristics for matching BOLT-added split functions.
+
+# RUN: llvm-mc --filetype=obj --triple x86_64-unknown-unknown %S/cdsplit-symbol-names.s -o %t.main.o
+# RUN: llvm-mc --filetype=obj --triple x86_64-unknown-unknown %s -o %t.chain.o
+# RUN: link_fdata %S/cdsplit-symbol-names.s %t.main.o %t.fdata
+# RUN: sed -i 's|chain|chain/2|g' %t.fdata
+# RUN: llvm-strip --strip-unneeded %t.main.o
+# RUN: llvm-objcopy --localize-symbol=chain %t.main.o
+# RUN: %clang %cflags %t.chain.o %t.main.o -o %t.exe -Wl,-q
+# RUN: llvm-bolt %t.exe -o %t.bolt --split-functions --split-strategy=randomN \
+# RUN:   --reorder-blocks=ext-tsp --enable-bat --bolt-seed=7 --data=%t.fdata
+# RUN: llvm-objdump --syms %t.bolt | FileCheck %s --check-prefix=CHECK-SYMS
+
+# RUN: link_fdata %s %t.bolt %t.preagg PREAGG
+# PREAGG: B X:0 #chain.cold.0# 1 0
+# RUN: perf2bolt %t.bolt -p %t.preagg --pa -o %t.bat.fdata -w %t.bat.yaml -v=1 \
+# RUN:   | FileCheck %s --check-prefix=CHECK-REGISTER
+
+# CHECK-SYMS: l df *ABS*          [[#]] chain.s
+# CHECK-SYMS: l  F .bolt.org.text [[#]] chain
+# CHECK-SYMS: l  F .text.cold     [[#]] chain.cold.0
+# CHECK-SYMS: l  F .text          [[#]] chain
+# CHECK-SYMS: l df *ABS*          [[#]] bolt-pseudo.o
+
+# CHECK-REGISTER: BOLT-INFO: marking chain.cold.0/1(*2) as a fragment of chain/2(*2)
+
+.file "chain.s"
+        .text
+        .type   chain, @function
+chain:
+        ret
+        .size   chain, .-chain

>From a94e14566de73e4a54a28086c95d742a1f09e7b4 Mon Sep 17 00:00:00 2001
From: Amir Ayupov <aaupov at fb.com>
Date: Mon, 29 Apr 2024 12:50:07 -0700
Subject: [PATCH 3/3] Fix a mistake in NameOrError

---
 bolt/lib/Rewrite/RewriteInstance.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/bolt/lib/Rewrite/RewriteInstance.cpp b/bolt/lib/Rewrite/RewriteInstance.cpp
index 8eb2e5a9d9120a..5e7bcd06df82c4 100644
--- a/bolt/lib/Rewrite/RewriteInstance.cpp
+++ b/bolt/lib/Rewrite/RewriteInstance.cpp
@@ -1515,7 +1515,7 @@ void RewriteInstance::registerFragments() {
     // symbol.
     for (ELFSymbolRef NextSymbol = Symbol; NextSymbol < StopSymbol;
          NextSymbol.moveNext()) {
-      Expected<StringRef> NameOrError = Symbol.getName();
+      Expected<StringRef> NameOrError = NextSymbol.getName();
       if (!NameOrError)
         break;
       StringRef Name = *NameOrError;