[llvm] 56a8655 - [CodeGen] Expose the extensibility of PassConfig to plugins (#139059)
via llvm-commits
llvm-commits at lists.llvm.org
Thu Jul 10 03:43:13 PDT 2025
Author: Tcc100
Date: 2025-07-10T12:43:09+02:00
New Revision: 56a8655f4a9c3992fd401dcf12b956f24f0e2606
URL: https://github.com/llvm/llvm-project/commit/56a8655f4a9c3992fd401dcf12b956f24f0e2606
DIFF: https://github.com/llvm/llvm-project/commit/56a8655f4a9c3992fd401dcf12b956f24f0e2606.diff
LOG: [CodeGen] Expose the extensibility of PassConfig to plugins (#139059)
This PR exposes the backend pass config to plugins via a callback.
Plugin authors can register a callback that is being triggered before
the target backend adds their passes to the pipeline. In the callback
they then get access to the `TargetMachine`, the `PassManager`, and the
`TargetPassConfig`. This allows plugins to call
`TargetPassConfig::insertPass`, which is honored in the subsequent
`addPass` of the main backend. We implemented this using the legacy pass
manager since backends still use it as the default.
Added:
llvm/include/llvm/Target/RegisterTargetPassConfigCallback.h
llvm/lib/Target/RegisterTargetPassConfigCallback.cpp
llvm/test/Other/codegen-plugin-loading.ll
llvm/unittests/CodeGen/CGPluginTest/CMakeLists.txt
llvm/unittests/CodeGen/CGPluginTest/Plugin/CMakeLists.txt
llvm/unittests/CodeGen/CGPluginTest/Plugin/CodeGenTestPass.cpp
llvm/unittests/CodeGen/CGPluginTest/Plugin/CodeGenTestPass.h
llvm/unittests/CodeGen/CGPluginTest/Plugin/Plugin.cpp
llvm/unittests/CodeGen/CGPluginTest/PluginTest.cpp
Modified:
llvm/docs/WritingAnLLVMPass.rst
llvm/lib/CodeGen/CodeGenTargetMachineImpl.cpp
llvm/lib/Target/CMakeLists.txt
llvm/unittests/CodeGen/CMakeLists.txt
Removed:
################################################################################
diff --git a/llvm/docs/WritingAnLLVMPass.rst b/llvm/docs/WritingAnLLVMPass.rst
index 484227bac38b5..9c2c38350701a 100644
--- a/llvm/docs/WritingAnLLVMPass.rst
+++ b/llvm/docs/WritingAnLLVMPass.rst
@@ -442,6 +442,28 @@ in certain circumstances (such as calling the ``Pass::dump()`` from a
debugger), so it should only be used to enhance debug output, it should not be
depended on.
+Scheduling a MachineFunctionPass
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Backends create a ``TargetPassConfig`` and use ``addPass`` to schedule
+``MachineFunctionPass``\ es. External plugins can register a callback to modify
+and insert additional passes:
+
+.. code-block:: c++
+
+ RegisterTargetPassConfigCallback X{[](auto &TM, auto &PM, auto *TPC) {
+ TPC->insertPass(/* ... */);
+ TPC->substitutePass(/* ... */);
+ }};
+
+Note that passes still have to be registered:
+
+.. code-block:: c++
+
+ __attribute__((constructor)) static void initCodeGenPlugin() {
+ initializeExamplePass(*PassRegistry::getPassRegistry());
+ }
+
.. _writing-an-llvm-pass-interaction:
Specifying interactions between passes
diff --git a/llvm/include/llvm/Target/RegisterTargetPassConfigCallback.h b/llvm/include/llvm/Target/RegisterTargetPassConfigCallback.h
new file mode 100644
index 0000000000000..d7c9cb21e15d4
--- /dev/null
+++ b/llvm/include/llvm/Target/RegisterTargetPassConfigCallback.h
@@ -0,0 +1,37 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// This file contains the registry for PassConfigCallbacks that enable changes
+/// to the TargetPassConfig during the initialization of TargetMachine.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TARGET_REGISTERTARGETPASSCONFIGCALLBACK_H
+#define LLVM_TARGET_REGISTERTARGETPASSCONFIGCALLBACK_H
+
+#include "TargetMachine.h"
+
+namespace llvm {
+
+using PassConfigCallback =
+ std::function<void(TargetMachine &, PassManagerBase &, TargetPassConfig *)>;
+
+class RegisterTargetPassConfigCallback {
+public:
+ PassConfigCallback Callback;
+
+ explicit RegisterTargetPassConfigCallback(PassConfigCallback &&C);
+ ~RegisterTargetPassConfigCallback();
+};
+
+void invokeGlobalTargetPassConfigCallbacks(TargetMachine &TM,
+ PassManagerBase &PM,
+ TargetPassConfig *PassConfig);
+} // namespace llvm
+
+#endif // LLVM_TARGET_REGISTERTARGETPASSCONFIGCALLBACK_H
diff --git a/llvm/lib/CodeGen/CodeGenTargetMachineImpl.cpp b/llvm/lib/CodeGen/CodeGenTargetMachineImpl.cpp
index e54419758410a..442ec38409307 100644
--- a/llvm/lib/CodeGen/CodeGenTargetMachineImpl.cpp
+++ b/llvm/lib/CodeGen/CodeGenTargetMachineImpl.cpp
@@ -30,6 +30,7 @@
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FormattedStream.h"
+#include "llvm/Target/RegisterTargetPassConfigCallback.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetOptions.h"
using namespace llvm;
@@ -122,6 +123,7 @@ addPassesToGenerateCode(CodeGenTargetMachineImpl &TM, PassManagerBase &PM,
PassConfig->setDisableVerify(DisableVerify);
PM.add(PassConfig);
PM.add(&MMIWP);
+ invokeGlobalTargetPassConfigCallbacks(TM, PM, PassConfig);
if (PassConfig->addISelPasses())
return nullptr;
diff --git a/llvm/lib/Target/CMakeLists.txt b/llvm/lib/Target/CMakeLists.txt
index f5f6f5386f899..e26e00ea3fdfd 100644
--- a/llvm/lib/Target/CMakeLists.txt
+++ b/llvm/lib/Target/CMakeLists.txt
@@ -3,6 +3,7 @@ list(APPEND LLVM_COMMON_DEPENDS intrinsics_gen)
list(APPEND LLVM_TABLEGEN_FLAGS -I ${LLVM_MAIN_SRC_DIR}/lib/Target)
add_llvm_component_library(LLVMTarget
+ RegisterTargetPassConfigCallback.cpp
Target.cpp
TargetLoweringObjectFile.cpp
TargetMachine.cpp
diff --git a/llvm/lib/Target/RegisterTargetPassConfigCallback.cpp b/llvm/lib/Target/RegisterTargetPassConfigCallback.cpp
new file mode 100644
index 0000000000000..a80b8b825b18a
--- /dev/null
+++ b/llvm/lib/Target/RegisterTargetPassConfigCallback.cpp
@@ -0,0 +1,39 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// This file contains the registry for PassConfigCallbacks that enable changes
+/// to the TargetPassConfig during the initialization of TargetMachine.
+///
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Target/RegisterTargetPassConfigCallback.h"
+
+namespace llvm {
+// TargetPassConfig callbacks
+static SmallVector<RegisterTargetPassConfigCallback *, 1>
+ TargetPassConfigCallbacks{};
+
+void invokeGlobalTargetPassConfigCallbacks(TargetMachine &TM,
+ PassManagerBase &PM,
+ TargetPassConfig *PassConfig) {
+ for (const RegisterTargetPassConfigCallback *Reg : TargetPassConfigCallbacks)
+ Reg->Callback(TM, PM, PassConfig);
+}
+
+RegisterTargetPassConfigCallback::RegisterTargetPassConfigCallback(
+ PassConfigCallback &&C)
+ : Callback(std::move(C)) {
+ TargetPassConfigCallbacks.push_back(this);
+}
+
+RegisterTargetPassConfigCallback::~RegisterTargetPassConfigCallback() {
+ const auto &It = find(TargetPassConfigCallbacks, this);
+ if (It != TargetPassConfigCallbacks.end())
+ TargetPassConfigCallbacks.erase(It);
+}
+} // namespace llvm
diff --git a/llvm/test/Other/codegen-plugin-loading.ll b/llvm/test/Other/codegen-plugin-loading.ll
new file mode 100644
index 0000000000000..652bbcdef36c3
--- /dev/null
+++ b/llvm/test/Other/codegen-plugin-loading.ll
@@ -0,0 +1,7 @@
+; RUN: llc -load %llvmshlibdir/../unittests/CodeGen/CGPluginTest/CGTestPlugin%pluginext %s -o - | FileCheck %s
+; REQUIRES: native, system-linux, llvm-dylib
+
+; CHECK: CodeGen Test Pass running on main
+define void @main() {
+ ret void
+}
diff --git a/llvm/unittests/CodeGen/CGPluginTest/CMakeLists.txt b/llvm/unittests/CodeGen/CGPluginTest/CMakeLists.txt
new file mode 100644
index 0000000000000..51ef85ab279cd
--- /dev/null
+++ b/llvm/unittests/CodeGen/CGPluginTest/CMakeLists.txt
@@ -0,0 +1,18 @@
+set(LLVM_LINK_COMPONENTS
+ ${LLVM_TARGETS_TO_BUILD}
+ Support
+ Core
+ Target
+ CodeGen
+ )
+
+add_llvm_unittest(CGPluginTest
+ PluginTest.cpp
+ Plugin/CodeGenTestPass.cpp
+
+ EXPORT_SYMBOLS
+ )
+target_link_libraries(CGPluginTest PRIVATE LLVMTestingSupport)
+
+unset(LLVM_LINK_COMPONENTS)
+add_subdirectory(Plugin)
diff --git a/llvm/unittests/CodeGen/CGPluginTest/Plugin/CMakeLists.txt b/llvm/unittests/CodeGen/CGPluginTest/Plugin/CMakeLists.txt
new file mode 100644
index 0000000000000..04f7738507b0d
--- /dev/null
+++ b/llvm/unittests/CodeGen/CGPluginTest/Plugin/CMakeLists.txt
@@ -0,0 +1,17 @@
+if (NOT WIN32 AND NOT CYGWIN)
+ unset(LLVM_LINK_COMPONENTS)
+ add_llvm_library(CGTestPlugin MODULE BUILDTREE_ONLY
+ CodeGenTestPass.cpp
+ Plugin.cpp
+ )
+
+ # Put PLUGIN next to the unit test executable.
+ set_output_directory(CGTestPlugin
+ BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR}/../
+ LIBRARY_DIR ${CMAKE_CURRENT_BINARY_DIR}/${CMAKE_CFG_INTDIR}/../
+ )
+ set_target_properties(CGTestPlugin PROPERTIES FOLDER "Tests")
+
+ add_dependencies(CGTestPlugin intrinsics_gen vt_gen)
+ add_dependencies(CGPluginTest CGTestPlugin)
+endif ()
diff --git a/llvm/unittests/CodeGen/CGPluginTest/Plugin/CodeGenTestPass.cpp b/llvm/unittests/CodeGen/CGPluginTest/Plugin/CodeGenTestPass.cpp
new file mode 100644
index 0000000000000..990d23258891f
--- /dev/null
+++ b/llvm/unittests/CodeGen/CGPluginTest/Plugin/CodeGenTestPass.cpp
@@ -0,0 +1,34 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeGenTestPass.h"
+
+#include "llvm/CodeGen/MachineFrameInfo.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "codegen-test"
+#define CODEGEN_TEST_NAME "CodeGen Test Pass"
+
+CodeGenTest::CodeGenTest() : MachineFunctionPass(ID) {}
+
+bool CodeGenTest::runOnMachineFunction(MachineFunction &MF) {
+ outs() << CODEGEN_TEST_NAME << " running on " << MF.getName()
+ << "\n"; // used for the lit test
+ if (RunCallback)
+ RunCallback();
+ return true;
+}
+
+StringRef CodeGenTest::getPassName() const { return CODEGEN_TEST_NAME; }
+
+char CodeGenTest::ID = 0;
+std::function<void()> CodeGenTest::RunCallback;
+
+INITIALIZE_PASS(CodeGenTest, DEBUG_TYPE, CODEGEN_TEST_NAME, false, false)
diff --git a/llvm/unittests/CodeGen/CGPluginTest/Plugin/CodeGenTestPass.h b/llvm/unittests/CodeGen/CGPluginTest/Plugin/CodeGenTestPass.h
new file mode 100644
index 0000000000000..8eaf6d5339657
--- /dev/null
+++ b/llvm/unittests/CodeGen/CGPluginTest/Plugin/CodeGenTestPass.h
@@ -0,0 +1,33 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef CODEGEN_TEST_PASS
+#define CODEGEN_TEST_PASS
+
+#include <llvm/CodeGen/MachineFunctionPass.h>
+
+using namespace llvm;
+
+namespace llvm {
+void initializeCodeGenTestPass(PassRegistry &);
+} // namespace llvm
+
+class CodeGenTest : public MachineFunctionPass {
+public:
+ static char ID;
+
+ CodeGenTest();
+
+ bool runOnMachineFunction(MachineFunction &MF) override;
+
+ StringRef getPassName() const override;
+
+ static std::function<void()> RunCallback;
+};
+
+#endif // CODEGEN_TEST_PASS
diff --git a/llvm/unittests/CodeGen/CGPluginTest/Plugin/Plugin.cpp b/llvm/unittests/CodeGen/CGPluginTest/Plugin/Plugin.cpp
new file mode 100644
index 0000000000000..ca2f1b929f633
--- /dev/null
+++ b/llvm/unittests/CodeGen/CGPluginTest/Plugin/Plugin.cpp
@@ -0,0 +1,26 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "CodeGenTestPass.h"
+
+#include <llvm/CodeGen/Passes.h>
+#include <llvm/CodeGen/TargetPassConfig.h>
+#include <llvm/Target/RegisterTargetPassConfigCallback.h>
+
+using namespace llvm;
+
+namespace {
+[[maybe_unused]] RegisterTargetPassConfigCallback X{
+ [](auto &TM, auto &PM, auto *TPC) {
+ TPC->insertPass(&GCLoweringID, &CodeGenTest::ID);
+ }};
+} // namespace
+
+__attribute__((constructor)) static void initCodeGenPlugin() {
+ initializeCodeGenTestPass(*PassRegistry::getPassRegistry());
+}
diff --git a/llvm/unittests/CodeGen/CGPluginTest/PluginTest.cpp b/llvm/unittests/CodeGen/CGPluginTest/PluginTest.cpp
new file mode 100644
index 0000000000000..bb8bea6d2e084
--- /dev/null
+++ b/llvm/unittests/CodeGen/CGPluginTest/PluginTest.cpp
@@ -0,0 +1,105 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "Plugin/CodeGenTestPass.h"
+
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/CodeGen/Passes.h"
+#include "llvm/CodeGen/TargetPassConfig.h"
+#include "llvm/Config/config.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/MC/TargetRegistry.h"
+#include "llvm/Support/DynamicLibrary.h"
+#include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/TargetSelect.h"
+#include "llvm/Target/RegisterTargetPassConfigCallback.h"
+#include "llvm/Target/TargetMachine.h"
+
+#include "gtest/gtest.h"
+
+using namespace llvm;
+
+namespace {
+void anchor() {}
+
+std::string libPath(const std::string &Name) {
+ const auto &Argvs = testing::internal::GetArgvs();
+ const char *Argv0 = Argvs.size() > 0 ? Argvs[0].c_str() : "CGPluginTest";
+ void *Ptr = (void *)(intptr_t)anchor;
+ std::string Path = sys::fs::getMainExecutable(Argv0, Ptr);
+ SmallString<256> Buf{sys::path::parent_path(Path)};
+ sys::path::append(Buf, (Name + LLVM_PLUGIN_EXT).c_str());
+ return std::string(Buf.str());
+}
+} // namespace
+
+namespace llvm {
+class CGPluginTests : public testing::Test {
+protected:
+ static void SetUpTestCase() {
+ InitializeAllTargetMCs();
+ InitializeAllTargetInfos();
+ InitializeAllTargets();
+ }
+};
+} // namespace llvm
+
+TEST_F(CGPluginTests, LoadPlugin) {
+#if !defined(LLVM_ENABLE_PLUGINS)
+ // Skip the test if plugins are disabled.
+ GTEST_SKIP();
+#endif
+
+ auto PluginPath = libPath("CGTestPlugin");
+ ASSERT_NE("", PluginPath);
+
+ std::string Error;
+ auto Library = sys::DynamicLibrary::getLibrary(PluginPath.c_str(), &Error);
+ ASSERT_TRUE(Library.isValid()) << Error;
+ sys::DynamicLibrary::closeLibrary(Library);
+}
+
+TEST_F(CGPluginTests, ExecuteCallback) {
+#if !defined(LLVM_ENABLE_PLUGINS)
+ // Skip the test if plugins are disabled.
+ GTEST_SKIP();
+#endif
+
+ volatile bool CallbackExecuted = false;
+ volatile bool MPassExecuted = false;
+
+ RegisterTargetPassConfigCallback X{[&](auto &TM, auto &PM, auto *TPC) {
+ CallbackExecuted = true;
+ TPC->insertPass(&GCLoweringID, &CodeGenTest::ID);
+ }};
+
+ CodeGenTest::RunCallback = [&] { MPassExecuted = true; };
+
+ TargetOptions Options;
+ std::unique_ptr<MCContext> MCC;
+ for (auto T : TargetRegistry::targets()) {
+ if (!T.hasTargetMachine())
+ continue;
+ Triple TT{T.getName(), "", ""};
+ auto *TM = T.createTargetMachine(TT, "", "", Options, std::nullopt,
+ std::nullopt, CodeGenOptLevel::Default);
+ ASSERT_TRUE(TM);
+
+ legacy::PassManager PM;
+ MCC.reset(new MCContext(TT, TM->getMCAsmInfo(), TM->getMCRegisterInfo(),
+ TM->getMCSubtargetInfo()));
+ auto *PtrMCC = MCC.get();
+ CallbackExecuted = false;
+ MPassExecuted = false;
+ if (TM->addPassesToEmitMC(PM, PtrMCC, outs()) == true)
+ continue;
+ ASSERT_TRUE(CallbackExecuted) << T.getName() << " callback failed";
+ ASSERT_TRUE(MPassExecuted) << T.getName() << " MachinePass failed";
+ }
+}
diff --git a/llvm/unittests/CodeGen/CMakeLists.txt b/llvm/unittests/CodeGen/CMakeLists.txt
index 8b025219c46cf..d19b122676c9b 100644
--- a/llvm/unittests/CodeGen/CMakeLists.txt
+++ b/llvm/unittests/CodeGen/CMakeLists.txt
@@ -51,5 +51,6 @@ add_llvm_unittest(CodeGenTests
)
add_subdirectory(GlobalISel)
+add_subdirectory(CGPluginTest)
target_link_libraries(CodeGenTests PRIVATE LLVMTestingSupport)
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