[llvm] [BOLT] Link pthread in Profile and Target libs to fix undefined pthre… (PR #215748)

[Kito Cheng via llvm-commits]

https://github.com/kito-cheng created https://github.com/llvm/llvm-project/pull/215748

…ad_rwlock_* symbols

MCPlusBuilder.h uses llvm::sys::RWMutex, which aliases std::shared_mutex on non-Apple platforms. Its inline lock/unlock calls pthread_rwlock_* directly, so any shared library that instantiates these inline functions must link pthread explicitly under -Wl,-z,defs.

This only shows up when building with -DBUILD_SHARED_LIBS=ON. With static libs, the missing symbols get resolved elsewhere on the final link line, so the problem stays hidden.

LLVMBOLTCore, LLVMBOLTRewrite, LLVMBOLTPasses, and LLVMBOLTUtils already link ${LLVM_PTHREAD_LIB}; LLVMBOLTProfile and the LLVMBOLTTarget{X86, AArch64,RISCV} libs were missing it, causing link failures.

>From 4238423d64e2facf181a4746b3ec15b33bf19482 Mon Sep 17 00:00:00 2001
From: Kito Cheng <kito.cheng at sifive.com>
Date: Wed, 12 Aug 2026 00:12:33 -0700
Subject: [PATCH] [BOLT] Link pthread in Profile and Target libs to fix
 undefined pthread_rwlock_* symbols

MCPlusBuilder.h uses llvm::sys::RWMutex, which aliases std::shared_mutex
on non-Apple platforms. Its inline lock/unlock calls pthread_rwlock_*
directly, so any shared library that instantiates these inline
functions must link pthread explicitly under -Wl,-z,defs.

This only shows up when building with -DBUILD_SHARED_LIBS=ON. With
static libs, the missing symbols get resolved elsewhere on the final
link line, so the problem stays hidden.

LLVMBOLTCore, LLVMBOLTRewrite, LLVMBOLTPasses, and LLVMBOLTUtils already
link ${LLVM_PTHREAD_LIB}; LLVMBOLTProfile and the LLVMBOLTTarget{X86,
AArch64,RISCV} libs were missing it, causing link failures.
---
 bolt/lib/Profile/CMakeLists.txt        | 3 +++
 bolt/lib/Target/AArch64/CMakeLists.txt | 3 +++
 bolt/lib/Target/RISCV/CMakeLists.txt   | 3 +++
 bolt/lib/Target/X86/CMakeLists.txt     | 3 +++
 4 files changed, 12 insertions(+)

diff --git a/bolt/lib/Profile/CMakeLists.txt b/bolt/lib/Profile/CMakeLists.txt
index a6686510f91a7..c4c6403be3a55 100644
--- a/bolt/lib/Profile/CMakeLists.txt
+++ b/bolt/lib/Profile/CMakeLists.txt
@@ -10,6 +10,9 @@ add_llvm_library(LLVMBOLTProfile
   NO_EXPORT
   DISABLE_LLVM_LINK_LLVM_DYLIB
 
+  LINK_LIBS
+  ${LLVM_PTHREAD_LIB}
+
   LINK_COMPONENTS
   BinaryFormat
   Demangle
diff --git a/bolt/lib/Target/AArch64/CMakeLists.txt b/bolt/lib/Target/AArch64/CMakeLists.txt
index 1e171748aece6..715efc1e8c5a4 100644
--- a/bolt/lib/Target/AArch64/CMakeLists.txt
+++ b/bolt/lib/Target/AArch64/CMakeLists.txt
@@ -25,6 +25,9 @@ add_llvm_library(LLVMBOLTTargetAArch64
   NO_EXPORT
   DISABLE_LLVM_LINK_LLVM_DYLIB
 
+  LINK_LIBS
+  ${LLVM_PTHREAD_LIB}
+
   DEPENDS
   AArch64CommonTableGen
   )
diff --git a/bolt/lib/Target/RISCV/CMakeLists.txt b/bolt/lib/Target/RISCV/CMakeLists.txt
index 6c3a196f8a1fe..45645a98d132f 100644
--- a/bolt/lib/Target/RISCV/CMakeLists.txt
+++ b/bolt/lib/Target/RISCV/CMakeLists.txt
@@ -23,6 +23,9 @@ add_llvm_library(LLVMBOLTTargetRISCV
   NO_EXPORT
   DISABLE_LLVM_LINK_LLVM_DYLIB
 
+  LINK_LIBS
+  ${LLVM_PTHREAD_LIB}
+
   DEPENDS
   RISCVCommonTableGen
   )
diff --git a/bolt/lib/Target/X86/CMakeLists.txt b/bolt/lib/Target/X86/CMakeLists.txt
index 6d1accb5e8159..0da4713b191aa 100644
--- a/bolt/lib/Target/X86/CMakeLists.txt
+++ b/bolt/lib/Target/X86/CMakeLists.txt
@@ -24,6 +24,9 @@ add_llvm_library(LLVMBOLTTargetX86
   NO_EXPORT
   DISABLE_LLVM_LINK_LLVM_DYLIB
 
+  LINK_LIBS
+  ${LLVM_PTHREAD_LIB}
+
   DEPENDS
   X86CommonTableGen
   )