Add LLVM-pass plugin support to LDC. Commandline flag: -plugin=....

CMakeLists.txt

@@ -321,6 +321,7 @@ set(DRV_SRC
     driver/linker-gcc.cpp
     driver/linker-msvc.cpp
     driver/main.cpp
+    driver/plugins.cpp
     ${CMAKE_BINARY_DIR}/driver/ldc-version.cpp
 )
 set(DRV_HDR
@@ -337,6 +338,7 @@ set(DRV_HDR
     driver/ldc-version.h
     driver/archiver.h
     driver/linker.h
+    driver/plugins.h
     driver/targetmachine.h
     driver/toobj.h
     driver/tool.h
@@ -559,6 +561,23 @@ if(LDC_WITH_LLD)
     endif()
 endif()
 
+# Plugin support
+if(APPLE)
+    # There doesn't seem to be a downside to enabling plugins on macOS
+    set(LDC_ENABLE_PLUGINS_DEFAULT ON)
+else()
+    set(LDC_ENABLE_PLUGINS_DEFAULT OFF)
+endif()
+set(LDC_ENABLE_PLUGINS ${LDC_ENABLE_PLUGINS_DEFAULT} CACHE BOOL "Build LDC with plugin support (increases binary size)")
+if(LDC_ENABLE_PLUGINS)
+    message(STATUS "Building LDC with plugin support")
+    add_definitions(-DLDC_ENABLE_PLUGINS)
+    # For plugin support, we need to link with --export-dynamic on Unix.
+    if(UNIX AND NOT APPLE)
+        set(LDC_LINKERFLAG_LIST "${LDC_LINKERFLAG_LIST};-Wl,--export-dynamic")
+    endif()
+endif()
+
 set(LDC_LINK_MANUALLY OFF)
 if(UNIX AND (CMAKE_COMPILER_IS_GNUCXX OR (${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang")))
     # On Unix-like systems, DMD and LDC will use the C compiler for linking, but

driver/main.cpp

@@ -29,6 +29,7 @@
 #include "driver/exe_path.h"
 #include "driver/ldc-version.h"
 #include "driver/linker.h"
+#include "driver/plugins.h"
 #include "driver/targetmachine.h"
 #include "gen/cl_helpers.h"
 #include "gen/irstate.h"
@@ -1063,6 +1064,8 @@ int cppmain(int argc, char **argv) {
   opts::initializeInstrumentationOptionsFromCmdline(
       *global.params.targetTriple);
 
+  loadAllPlugins();
+
   Strings libmodules;
   return mars_mainBody(files, libmodules);
 }

driver/plugins.cpp

@@ -0,0 +1,48 @@
+//===-- driver/plugins.cpp -------------------------------------*-  C++ -*-===//
+//
+//                         LDC – the LLVM D compiler
+//
+// This file is distributed under the BSD-style LDC license. See the LICENSE
+// file for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Implements functionality related to plugins (`-plugin=...`).
+//
+//===----------------------------------------------------------------------===//
+
+#include "driver/plugins.h"
+
+#if LDC_ENABLE_PLUGINS
+
+#include "errors.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/DynamicLibrary.h"
+
+namespace {
+namespace cl = llvm::cl;
+
+cl::list<std::string>
+    pluginFiles("plugin", cl::CommaSeparated, cl::desc("Plugins to load."),
+                cl::value_desc("<dynamic_library.so, lib2.so>"));
+
+} // anonymous namespace
+
+/// Loads all plugins. The static constructor of each plugin should take care of
+/// the plugins registering themself with the rest of LDC/LLVM.
+void loadAllPlugins() {
+  for (auto &filename : pluginFiles) {
+    std::string errorString;
+    if (llvm::sys::DynamicLibrary::LoadLibraryPermanently(filename.c_str(),
+                                                          &errorString)) {
+      error(Loc(), "Error loading plugin '%s': %s", filename.c_str(),
+            errorString.c_str());
+    }
+  }
+}
+
+#else // #if LDC_ENABLE_PLUGINS
+
+void loadAllPlugins() {}
+
+#endif // LDC_ENABLE_PLUGINS

driver/plugins.h

@@ -0,0 +1,15 @@
+//===-- driver/plugins.h ---------------------------------------*-  C++ -*-===//
+//
+//                         LDC – the LLVM D compiler
+//
+// This file is distributed under the BSD-style LDC license. See the LICENSE
+// file for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LDC_DRIVER_PLUGINS_H
+#define LDC_DRIVER_PLUGINS_H
+
+void loadAllPlugins();
+
+#endif // LDC_DRIVER_PLUGINS_H

tests/lit.site.cfg.in

@@ -22,6 +22,7 @@ config.llvm_targetsstr     = "@LLVM_TARGETS_TO_BUILD@"
 config.default_target_bits = @DEFAULT_TARGET_BITS@
 config.with_PGO            = True
 config.dynamic_compile     = @LDC_DYNAMIC_COMPILE@
+config.plugins_supported   = "@LDC_ENABLE_PLUGINS@" == "ON"
 
 config.name = 'LDC'
 

tests/plugins/addFuncEntryCall/Makefile

@@ -0,0 +1,28 @@
+
+# ROOT_DIR = directory where Makefile sits
+MAKEFILE_PATH := $(abspath $(lastword $(MAKEFILE_LIST)))
+ROOT_DIR := $(dir $(MAKEFILE_PATH))
+
+LLVM_CONFIG ?= llvm-config
+
+CXXFLAGS ?= -O3
+CXXFLAGS += $(shell $(LLVM_CONFIG) --cxxflags) -fno-rtti -fpic
+# Remove all warning flags (they may or may not be supported by the compiler)
+CXXFLAGS := $(filter-out -W%,$(CXXFLAGS))
+CXXFLAGS := $(filter-out -fcolor-diagnostics,$(CXXFLAGS))
+
+ifeq "$(shell uname)" "Darwin"
+  CXXFLAGS += -Wl,-flat_namespace -Wl,-undefined,suppress
+endif
+
+PASSLIB = addFuncEntryCallPass
+
+all: $(PASSLIB)
+
+$(PASSLIB): $(ROOT_DIR)$(PASSLIB).cpp
+	$(CXX) $(CXXFLAGS) -shared $< -o $@.so
+
+.NOTPARALLEL: clean
+
+clean:
+	rm -f $(PASSLIB).so

tests/plugins/addFuncEntryCall/addFuncEntryCallPass.cpp

@@ -0,0 +1,60 @@
+//===-- addFuncEntryCallPass.cpp - Optimize druntime calls ----------------===//
+//
+//                         LDC – the LLVM D compiler
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See the LICENSE file for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Pass.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Transforms/IPO/PassManagerBuilder.h"
+
+using namespace llvm;
+
+namespace {
+
+class FuncEntryCallPass : public FunctionPass {
+
+  Constant *funcToCallUponEntry = nullptr;
+
+public:
+  static char ID;
+  FuncEntryCallPass() : FunctionPass(ID) {}
+
+  bool doInitialization(Module &M) override;
+  bool runOnFunction(Function &F) override;
+};
+}
+
+char FuncEntryCallPass::ID = 0;
+
+bool FuncEntryCallPass::doInitialization(Module &M) {
+  // Add fwd declaration of the `void __test_funcentrycall(void)` function.
+  auto functionType = FunctionType::get(Type::getVoidTy(M.getContext()), false);
+  funcToCallUponEntry =
+      M.getOrInsertFunction("__test_funcentrycall", functionType);
+  return true;
+}
+
+bool FuncEntryCallPass::runOnFunction(Function &F) {
+  // Add call to `__test_funcentrycall(void)` at the start of _every_ function
+  // (this includes e.g. `ldc.register_dso`!)
+  llvm::BasicBlock &block = F.getEntryBlock();
+  IRBuilder<> builder(&block, block.begin());
+  builder.CreateCall(funcToCallUponEntry);
+  return true;
+}
+
+static void addFuncEntryCallPass(const PassManagerBuilder &,
+                                 legacy::PassManagerBase &PM) {
+  PM.add(new FuncEntryCallPass());
+}
+// Registration of the plugin's pass is done by the plugin's static constructor.
+static RegisterStandardPasses
+    RegisterFuncEntryCallPass0(PassManagerBuilder::EP_EnabledOnOptLevel0,
+                               addFuncEntryCallPass);

tests/plugins/addFuncEntryCall/testPlugin.d

@@ -0,0 +1,14 @@
+// REQUIRES: Plugins
+
+// RUN: make -f %S/Makefile
+// RUN: %ldc -c -output-ll -plugin=./addFuncEntryCallPass.so -of=%t.ll %s
+// RUN: FileCheck %s < %t.ll
+
+// CHECK: define {{.*}}testfunction
+int testfunction(int i)
+{
+    // CHECK-NEXT: call {{.*}}__test_funcentrycall
+    return i * 2;
+}
+
+// CHECK-DAG: declare {{.*}}__test_funcentrycall

tests/plugins/lit.local.cfg

@@ -0,0 +1,7 @@
+import os
+import platform
+import re
+
+if (config.plugins_supported):
+    config.available_features.add('Plugins')
+    config.environment['LLVM_CONFIG'] = os.path.join(config.llvm_tools_dir, 'llvm-config')