[llvm] [BOLT][Linux] Fix static keys test case (PR #119771)

[Maksim Panchenko via llvm-commits]

https://github.com/maksfb created https://github.com/llvm/llvm-project/pull/119771

The key address in the static keys jump table was incorrectly encoded as an absolute value instead of PC-relative causing incorrect interpretation of the "likely" property of the key.

>From ca902ab373e8425fabb4a01108722e6d9c060709 Mon Sep 17 00:00:00 2001
From: Maksim Panchenko <maks at fb.com>
Date: Thu, 12 Dec 2024 13:47:05 -0800
Subject: [PATCH] [BOLT][Linux] Fix static keys test case

The key address in the static keys jump table was incorrectly encoded as
an absolute value instead of PC-relative causing incorrect
interpretation of the "likely" property of the key.
---
 bolt/test/X86/linux-static-keys.s | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/bolt/test/X86/linux-static-keys.s b/bolt/test/X86/linux-static-keys.s
index 0bd17a375d8824..d34dd640ef8790 100644
--- a/bolt/test/X86/linux-static-keys.s
+++ b/bolt/test/X86/linux-static-keys.s
@@ -35,13 +35,13 @@ _start:
 .L0:
   jmp L1
 # CHECK:      jit
-# CHECK-SAME: # ID: 1 {{.*}} # Likely: 0 # InitValue: 1
+# CHECK-SAME: # ID: 1 {{.*}} # Likely: 1 # InitValue: 0
   nop
 L1:
   .nops 5
-  jmp .L0
 # CHECK:      jit
-# CHECK-SAME: # ID: 2 {{.*}} # Likely: 1 # InitValue: 1
+# CHECK-SAME: # ID: 2 {{.*}} # Likely: 0 # InitValue: 0
+  jmp .L0
 
 ## Check that a branch profile associated with a NOP is handled properly when
 ## dynamic branch is created.
@@ -67,18 +67,24 @@ foo:
   .type __start___jump_table, %object
 __start___jump_table:
 
-  .long .L0 - . # Jump address
-  .long L1 - . # Target address
-  .quad 1       # Key address
+  .long .L0 - .                   # Jump address
+  .long L1 - .                    # Target address
+  .quad fake_static_key + 1 - .   # Key address; LSB = 1 : likely
 
-  .long L1 - . # Jump address
-  .long L2 - . # Target address
-  .quad 0       # Key address
+  .long L1 - .                    # Jump address
+  .long L2 - .                    # Target address
+  .quad fake_static_key -.        # Key address; LSB = 0 : unlikely
 
   .globl __stop___jump_table
   .type __stop___jump_table, %object
 __stop___jump_table:
 
+## Staic keys (we just use the label ignoring the format of the keys).
+  .data
+  .align 8
+fake_static_key:
+  .quad 0
+
 ## Fake Linux Kernel sections.
   .section __ksymtab,"a", at progbits
   .section __ksymtab_gpl,"a", at progbits