[clang] [llvm] [llvm] Enable LLVM_LINK_LLVM_DYLIB by default on non-Windows platforms (PR #138187)
Reid Kleckner via cfe-commits
cfe-commits at lists.llvm.org
Thu Jun 26 06:20:06 PDT 2025
https://github.com/rnk updated https://github.com/llvm/llvm-project/pull/138187
>From 7e23666e3366101d635648faf95aaf7245643b4e Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk at google.com>
Date: Wed, 30 Apr 2025 16:32:32 -0700
Subject: [PATCH 1/5] [llvm] Enable LLVM_LINK_LLVM_DYLIB by default on
non-Windows platforms
As discussed in the RFC thread [1], this build configuration is a better
default because it uses less RAM and disk to build LLVM, which makes it
more accessible to beginners. The downside to the libLLVM build is that
it increases tool binary startup time, which can have major impacts on
configuration script times and the LLVM test suite itself. However, it
is better for new users configuring LLVM builds for the first time.
Long-time developers with beefy machines who prefer the finer grained
dependencies of static linking can still use the old model by opting out
with -DLLVM_LINK_LLVM_DYLIB=OFF. The fine-grained shared lib build is
also still supported via -DBUILD_SHARED_LIBS=ON.
MLIR's dylib build is configured to follow the LLVM dylib build, so this
changes the default for MLIR as well.
[1] https://discourse.llvm.org/t/rfc-llvm-link-llvm-dylib-should-default-to-on-on-posix-platforms/85908/1
---
llvm/CMakeLists.txt | 16 ++++++++++++++--
llvm/docs/ReleaseNotes.md | 5 +++++
2 files changed, 19 insertions(+), 2 deletions(-)
diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
index dd9040400530b..fde0988a737bc 100644
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -904,14 +904,26 @@ if(NOT MSVC OR LLVM_BUILD_LLVM_DYLIB_VIS)
set(CAN_BUILD_LLVM_DYLIB ON)
endif()
-cmake_dependent_option(LLVM_LINK_LLVM_DYLIB "Link tools against the libllvm dynamic library" OFF
+# Link the tools against the libllvm DSO by default.
+set(LLVM_LINK_LLVM_DYLIB_default ON)
+if (BUILD_SHARED_LIBS OR WIN32)
+ set(LLVM_LINK_LLVM_DYLIB_default OFF)
+endif()
+
+cmake_dependent_option(LLVM_LINK_LLVM_DYLIB "Link tools against the libllvm dynamic library"
+ "${LLVM_LINK_LLVM_DYLIB_default}"
"CAN_BUILD_LLVM_DYLIB" OFF)
+message("LLVM_LINK_LLVM_DYLIB_default ${LLVM_LINK_LLVM_DYLIB_default}")
+message("BUILD_SHARED_LIBS ${BUILD_SHARED_LIBS}")
+message("LLVM_LINK_LLVM_DYLIB ${LLVM_LINK_LLVM_DYLIB}")
+
set(LLVM_BUILD_LLVM_DYLIB_default OFF)
if(LLVM_LINK_LLVM_DYLIB OR LLVM_BUILD_LLVM_C_DYLIB)
set(LLVM_BUILD_LLVM_DYLIB_default ON)
endif()
-cmake_dependent_option(LLVM_BUILD_LLVM_DYLIB "Build libllvm dynamic library" ${LLVM_BUILD_LLVM_DYLIB_default}
+cmake_dependent_option(LLVM_BUILD_LLVM_DYLIB "Build libllvm dynamic library"
+ "${LLVM_BUILD_LLVM_DYLIB_default}"
"CAN_BUILD_LLVM_DYLIB" OFF)
cmake_dependent_option(LLVM_DYLIB_EXPORT_INLINES "Force inline members of classes to be DLL exported when
diff --git a/llvm/docs/ReleaseNotes.md b/llvm/docs/ReleaseNotes.md
index aded1bd67ed76..748883d70c084 100644
--- a/llvm/docs/ReleaseNotes.md
+++ b/llvm/docs/ReleaseNotes.md
@@ -77,6 +77,11 @@ Changes to LLVM infrastructure
Changes to building LLVM
------------------------
+* On non-Windows platforms, LLVM now builds as a large shared library, libLLVM,
+ by default. To revert to the old behavior of producing and linking static
+ libraries, pass ``-DLLVM_LINK_LLVM_DYLIB=OFF`` to CMake when configuring your
+ build.
+
Changes to TableGen
-------------------
>From 1eb025c251812e41544b9e388541ccd529adb3b0 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk at google.com>
Date: Wed, 25 Jun 2025 15:56:40 +0000
Subject: [PATCH 2/5] Remove debug prints
---
llvm/CMakeLists.txt | 4 ----
1 file changed, 4 deletions(-)
diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
index a7b243e077cdd..cd2adf1cddace 100644
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -929,10 +929,6 @@ cmake_dependent_option(LLVM_LINK_LLVM_DYLIB "Link tools against the libllvm dyna
"${LLVM_LINK_LLVM_DYLIB_default}"
"CAN_BUILD_LLVM_DYLIB" OFF)
-message("LLVM_LINK_LLVM_DYLIB_default ${LLVM_LINK_LLVM_DYLIB_default}")
-message("BUILD_SHARED_LIBS ${BUILD_SHARED_LIBS}")
-message("LLVM_LINK_LLVM_DYLIB ${LLVM_LINK_LLVM_DYLIB}")
-
set(LLVM_BUILD_LLVM_DYLIB_default OFF)
if(LLVM_LINK_LLVM_DYLIB OR LLVM_BUILD_LLVM_C_DYLIB)
set(LLVM_BUILD_LLVM_DYLIB_default ON)
>From 788bd487bd45925e50b45b804c765917d72c6816 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk at google.com>
Date: Thu, 26 Jun 2025 04:01:07 +0000
Subject: [PATCH 3/5] Disable linking the dylib from TestingSupport, it only
uses Support
---
bolt/unittests/Profile/CMakeLists.txt | 2 --
llvm/lib/Testing/Support/CMakeLists.txt | 2 ++
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/bolt/unittests/Profile/CMakeLists.txt b/bolt/unittests/Profile/CMakeLists.txt
index ce01c6c4b949e..4d468372f27fc 100644
--- a/bolt/unittests/Profile/CMakeLists.txt
+++ b/bolt/unittests/Profile/CMakeLists.txt
@@ -15,8 +15,6 @@ target_link_libraries(ProfileTests
PRIVATE
LLVMBOLTCore
LLVMBOLTProfile
- LLVMTargetParser
- LLVMTestingSupport
)
foreach (tgt ${BOLT_TARGETS_TO_BUILD})
diff --git a/llvm/lib/Testing/Support/CMakeLists.txt b/llvm/lib/Testing/Support/CMakeLists.txt
index 6955271239ca6..e5f3af23a6a13 100644
--- a/llvm/lib/Testing/Support/CMakeLists.txt
+++ b/llvm/lib/Testing/Support/CMakeLists.txt
@@ -14,6 +14,8 @@ add_llvm_library(LLVMTestingSupport
ADDITIONAL_HEADER_DIRS
${LLVM_MAIN_INCLUDE_DIR}/llvm/Testing/Support
+ DISABLE_LLVM_LINK_LLVM_DYLIB
+
LINK_COMPONENTS
Support
)
>From 2f1529f1bf4434e1a7f81d58947137af021085b7 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk at google.com>
Date: Thu, 26 Jun 2025 04:07:23 +0000
Subject: [PATCH 4/5] Add release notes
---
clang/docs/ReleaseNotes.rst | 5 +++++
llvm/docs/ReleaseNotes.md | 2 +-
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst
index e1fe22393eebb..b4e89a2b18559 100644
--- a/clang/docs/ReleaseNotes.rst
+++ b/clang/docs/ReleaseNotes.rst
@@ -332,6 +332,11 @@ Non-comprehensive list of changes in this release
- Clang no longer rejects reinterpret_cast conversions between indirect
ARC-managed pointers and other pointer types. The prior behavior was overly
strict and inconsistent with the ARC specification.
+- On non-Windows platforms, Clang now builds as a large shared library,
+ ``libclang-cpp``, by default. To revert to the old behavior of producing and
+ linking static libraries, pass ``-DCLANG_LINK_CLANG_DYLIB=OFF`` to CMake when
+ configuring your build. The new behavior matches LLVM, which also builds as a
+ large shared library.
New Compiler Flags
------------------
diff --git a/llvm/docs/ReleaseNotes.md b/llvm/docs/ReleaseNotes.md
index d4b1e353499f5..b9d4673a93ac4 100644
--- a/llvm/docs/ReleaseNotes.md
+++ b/llvm/docs/ReleaseNotes.md
@@ -90,7 +90,7 @@ Changes to LLVM infrastructure
Changes to building LLVM
------------------------
-* On non-Windows platforms, LLVM now builds as a large shared library, libLLVM,
+* On non-Windows platforms, LLVM now builds as a large shared library, `libLLVM`,
by default. To revert to the old behavior of producing and linking static
libraries, pass ``-DLLVM_LINK_LLVM_DYLIB=OFF`` to CMake when configuring your
build.
>From 590420636be4a9c4ae27ed100111ba968ef479b5 Mon Sep 17 00:00:00 2001
From: Reid Kleckner <rnk at google.com>
Date: Thu, 26 Jun 2025 13:19:45 +0000
Subject: [PATCH 5/5] Remove bolt unittest dep on LLVMTestingSupport to fix
link
---
bolt/unittests/Core/CMakeLists.txt | 1 -
bolt/unittests/Core/MemoryMaps.cpp | 3 +--
llvm/lib/Testing/Support/CMakeLists.txt | 2 --
3 files changed, 1 insertion(+), 5 deletions(-)
diff --git a/bolt/unittests/Core/CMakeLists.txt b/bolt/unittests/Core/CMakeLists.txt
index 54e8ea10cda12..ab7e342dc9e77 100644
--- a/bolt/unittests/Core/CMakeLists.txt
+++ b/bolt/unittests/Core/CMakeLists.txt
@@ -20,7 +20,6 @@ target_link_libraries(CoreTests
LLVMBOLTRewrite
LLVMBOLTProfile
LLVMBOLTUtils
- LLVMTestingSupport
)
foreach (tgt ${BOLT_TARGETS_TO_BUILD})
diff --git a/bolt/unittests/Core/MemoryMaps.cpp b/bolt/unittests/Core/MemoryMaps.cpp
index b0cab5431bdd3..dc0051a7c43ee 100644
--- a/bolt/unittests/Core/MemoryMaps.cpp
+++ b/bolt/unittests/Core/MemoryMaps.cpp
@@ -12,7 +12,6 @@
#include "llvm/DebugInfo/DWARF/DWARFContext.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/TargetSelect.h"
-#include "llvm/Testing/Support/Error.h"
#include "gtest/gtest.h"
using namespace llvm;
@@ -110,7 +109,7 @@ TEST_P(MemoryMapsTester, ParseMultipleSegments) {
Error Err = DA.preprocessProfile(*BC);
// Ignore errors from perf2bolt when parsing memory events later on.
- ASSERT_THAT_ERROR(std::move(Err), Succeeded());
+ ASSERT_FALSE(!!Err) << "Expected success";
auto &BinaryMMapInfo = DA.getBinaryMMapInfo();
auto El = BinaryMMapInfo.find(Pid);
diff --git a/llvm/lib/Testing/Support/CMakeLists.txt b/llvm/lib/Testing/Support/CMakeLists.txt
index e5f3af23a6a13..6955271239ca6 100644
--- a/llvm/lib/Testing/Support/CMakeLists.txt
+++ b/llvm/lib/Testing/Support/CMakeLists.txt
@@ -14,8 +14,6 @@ add_llvm_library(LLVMTestingSupport
ADDITIONAL_HEADER_DIRS
${LLVM_MAIN_INCLUDE_DIR}/llvm/Testing/Support
- DISABLE_LLVM_LINK_LLVM_DYLIB
-
LINK_COMPONENTS
Support
)
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