[BOLT][test] Add pseudo-probe-split-func.test

[aaupov]

Add a test checking if pseudo probes can be encoded and decoded with
function splitting in BOLT.

Test Plan: bin/llvm-lit -a tools/bolt/test/X86/pseudo-probe-split-func.test

[llvmbot]

@llvm/pr-subscribers-bolt

Author: Amir Ayupov (aaupov)

Changes

Add a test checking if pseudo probes can be encoded and decoded with
function splitting in BOLT.

Test Plan: bin/llvm-lit -a tools/bolt/test/X86/pseudo-probe-split-func.test

---

Full diff: https://github.com/llvm/llvm-project/pull/139305.diff

2 Files Affected:

• (added) bolt/test/X86/Inputs/pseudo-probe-split-func.c (+20)
• (added) bolt/test/X86/pseudo-probe-split-func.test (+18)

diff --git a/bolt/test/X86/Inputs/pseudo-probe-split-func.c b/bolt/test/X86/Inputs/pseudo-probe-split-func.c
new file mode 100644
index 0000000000000..3f0edb3342178
--- /dev/null
+++ b/bolt/test/X86/Inputs/pseudo-probe-split-func.c
@@ -0,0 +1,20 @@
+#include <stdio.h>
+
+int bar(int x, int y) {
+  if (x % 3) {
+    return x - y;
+  }
+  return x + y;
+}
+
+void foo() {
+  int s, i = 0;
+  while (i++ < 4000 * 4000)
+    if (i % 91) s = bar(i, s); else s += 30;
+  printf("sum is %d\n", s);
+}
+
+int main() {
+  foo();
+  return 0;
+}
diff --git a/bolt/test/X86/pseudo-probe-split-func.test b/bolt/test/X86/pseudo-probe-split-func.test
new file mode 100644
index 0000000000000..0bce3eb82bb36
--- /dev/null
+++ b/bolt/test/X86/pseudo-probe-split-func.test
@@ -0,0 +1,18 @@
+## This test checks if pseudo probes are present in split fragments
+RUN: %clang %cflags %p/Inputs/pseudo-probe-split-func.c -o %t \
+RUN:   -O3 -fuse-ld=lld -fpseudo-probe-for-profiling -fno-omit-frame-pointer \
+RUN:   -mno-omit-leaf-frame-pointer -g -Wl,-q
+## Test pseudo probe encoding when hot fragments are emitted before cold
+RUN: llvm-bolt %t -o %t.out -split-functions --split-strategy=all -lite=0
+RUN: llvm-profgen --binary=%t.out --perfscript=1 --output=%t.null \
+RUN:   --show-disassembly-only --show-pseudo-probe | FileCheck %s
+## Test pseudo probe encoding when cold fragments are emitted before hot
+RUN: llvm-bolt %t -o %t.cold -split-functions --split-strategy=all -lite=0 \
+RUN:   --hot-functions-at-end
+RUN: llvm-profgen --binary=%t.cold --perfscript=1 --output=%t.null \
+RUN:   --show-disassembly-only --show-pseudo-probe | FileCheck %s
+CHECK: Disassembly of section .text.cold.3
+CHECK: <foo.cold.3>:
+CHECK: [Probe]:       FUNC: foo Index: 8  Type: Block
+CHECK: <main.cold.3>:
+CHECK: [Probe]:       FUNC: foo Index: 8  Type: Block  Inlined: @ main:2

[github-actions]

⚠️ C/C++ code formatter, clang-format found issues in your code. ⚠️

You can test this locally with the following command:

git-clang-format --diff HEAD~1 HEAD --extensions c -- bolt/test/X86/Inputs/pseudo-probe-split-func.c

View the diff from clang-format here.

diff --git a/bolt/test/X86/Inputs/pseudo-probe-split-func.c b/bolt/test/X86/Inputs/pseudo-probe-split-func.c
index 3f0edb334..8adf3bfc3 100644
--- a/bolt/test/X86/Inputs/pseudo-probe-split-func.c
+++ b/bolt/test/X86/Inputs/pseudo-probe-split-func.c
@@ -10,7 +10,10 @@ int bar(int x, int y) {
 void foo() {
   int s, i = 0;
   while (i++ < 4000 * 4000)
-    if (i % 91) s = bar(i, s); else s += 30;
+    if (i % 91)
+      s = bar(i, s);
+    else
+      s += 30;
   printf("sum is %d\n", s);
 }
 

[maksfb]

Why is the test under x86?

There are several implicit assumptions about the compiled code in the test, such as the function being inlined and not optimized away.