Reland "[ELF] Enable new passmanager plugin support for LTO"

This is the orignal patch + a check that LLVM_BUILD_EXAMPLES is enabled before
adding a dependency on the 'Bye' example pass.

Original summary:

Add cli options for new passmanager plugin support to lld.

Currently it is not possible to load dynamic NewPM plugins with lld. This is an
incremental update to D76866. While that patch only added cli options for
llvm-lto2, this adds them for lld as well. This is especially useful for running
dynamic plugins on the linux kernel with LTO.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D120490

lld/ELF/Config.h

@@ -140,6 +140,7 @@ struct Configuration {
   std::vector<VersionDefinition> versionDefinitions;
   std::vector<llvm::StringRef> auxiliaryList;
   std::vector<llvm::StringRef> filterList;
+  std::vector<llvm::StringRef> passPlugins;
   std::vector<llvm::StringRef> searchPaths;
   std::vector<llvm::StringRef> symbolOrderingFile;
   std::vector<llvm::StringRef> thinLTOModulesToCompile;

lld/ELF/Driver.cpp

@@ -1287,6 +1287,8 @@ static void readConfigs(opt::InputArgList &args) {
       error(arg->getSpelling() + ": unknown plugin option '" + arg->getValue() +
             "'");
 
+  config->passPlugins = args::getStrings(args, OPT_load_pass_plugins);
+
   // Parse -mllvm options.
   for (auto *arg : args.filtered(OPT_mllvm))
     parseClangOption(arg->getValue(), arg->getSpelling());

lld/ELF/LTO.cpp

@@ -147,6 +147,8 @@ static lto::Config createConfig() {
 
   c.SampleProfile = std::string(config->ltoSampleProfile);
   c.UseNewPM = config->ltoNewPassManager;
+  for (StringRef pluginFn : config->passPlugins)
+    c.PassPlugins.push_back(std::string(pluginFn));
   c.DebugPassManager = config->ltoDebugPassManager;
   c.DwoDir = std::string(config->dwoDir);
 

lld/ELF/Options.td

@@ -716,3 +716,5 @@ defm check_dynamic_relocations: BB<"check-dynamic-relocations",
     "Perform additional validation of the written dynamic relocations",
     "Do not perform additional validation of the written dynamic relocations">,
   Flags<[HelpHidden]>;
+
+defm load_pass_plugins: EEq<"load-pass-plugin", "Load passes from plugin library">;

lld/test/CMakeLists.txt

@@ -12,6 +12,9 @@ llvm_canonicalize_cmake_booleans(
   LLVM_ENABLE_LIBXML2
   LLD_DEFAULT_LD_LLD_IS_MINGW
   LLVM_HAVE_LIBXAR
+  LLVM_BUILD_EXAMPLES
+  LLVM_ENABLE_PLUGINS
+  LLVM_BYE_LINK_INTO_TOOLS
   )
 
 configure_lit_site_cfg(
@@ -60,6 +63,11 @@ if (NOT LLD_BUILT_STANDALONE)
     split-file
     yaml2obj
     )
+    if (NOT WIN32 AND LLVM_BUILD_EXAMPLES)
+      list(APPEND LLD_TEST_DEPS
+        Bye
+        )
+    endif()
 endif()
 
 add_lit_testsuite(check-lld "Running lld test suite"

lld/test/ELF/lto/ltopasses-extension.ll

@@ -0,0 +1,13 @@
+; REQUIRES: x86, plugins, examples
+; UNSUPPORTED: windows
+; RUN: opt -module-summary %s -o %t.o
+; RUN: ld.lld -%loadnewpmbye --lto-newpm-passes="goodbye" -mllvm=%loadbye -mllvm=-wave-goodbye %t.o -o /dev/null 2>&1 | FileCheck %s
+; CHECK: Bye
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+@junk = global i32 0
+
+define i32* @somefunk() {
+  ret i32* @junk
+}

lld/test/lit.cfg.py

@@ -115,6 +115,24 @@ if config.have_dia_sdk:
 if config.sizeof_void_p == 8:
     config.available_features.add("llvm-64-bits")
 
+if config.has_plugins:
+    config.available_features.add('plugins')
+
+if config.build_examples:
+    config.available_features.add('examples')
+
+if config.linked_bye_extension:
+    config.substitutions.append(('%loadbye', ''))
+    config.substitutions.append(('%loadnewpmbye', ''))
+else:
+    config.substitutions.append(('%loadbye',
+                                 '-load={}/Bye{}'.format(config.llvm_shlib_dir,
+                                                         config.llvm_shlib_ext)))
+    config.substitutions.append(('%loadnewpmbye',
+                                 '-load-pass-plugin={}/Bye{}'
+                                 .format(config.llvm_shlib_dir,
+                                         config.llvm_shlib_ext)))
+
 tar_executable = lit.util.which('tar', config.environment['PATH'])
 if tar_executable:
     env = os.environ

lld/test/lit.site.cfg.py.in

@@ -7,6 +7,8 @@ config.llvm_src_root = "@LLVM_SOURCE_DIR@"
 config.llvm_obj_root = "@LLVM_BINARY_DIR@"
 config.llvm_tools_dir = lit_config.substitute("@LLVM_TOOLS_DIR@")
 config.llvm_libs_dir = lit_config.substitute("@LLVM_LIBS_DIR@")
+config.llvm_shlib_dir = "@SHLIBDIR@"
+config.llvm_shlib_ext = "@SHLIBEXT@"
 config.lit_tools_dir = "@LLVM_LIT_TOOLS_DIR@"
 config.errc_messages = "@LLVM_LIT_ERRC_MESSAGES@"
 config.lld_obj_root = "@LLD_BINARY_DIR@"
@@ -19,6 +21,9 @@ config.have_libxar = @LLVM_HAVE_LIBXAR@
 config.have_libxml2 = @LLVM_ENABLE_LIBXML2@
 config.sizeof_void_p = @CMAKE_SIZEOF_VOID_P@
 config.ld_lld_default_mingw = @LLD_DEFAULT_LD_LLD_IS_MINGW@
+config.build_examples = @LLVM_BUILD_EXAMPLES@
+config.has_plugins = @LLVM_ENABLE_PLUGINS@
+config.linked_bye_extension = @LLVM_BYE_LINK_INTO_TOOLS@
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)

llvm/examples/Bye/Bye.cpp

@@ -50,6 +50,11 @@ static llvm::RegisterStandardPasses RegisterBye(
     [](const llvm::PassManagerBuilder &Builder,
        llvm::legacy::PassManagerBase &PM) { PM.add(new LegacyBye()); });
 
+static llvm::RegisterStandardPasses RegisterByeLTO(
+    llvm::PassManagerBuilder::EP_ModuleOptimizerEarly,
+    [](const llvm::PassManagerBuilder &Builder,
+       llvm::legacy::PassManagerBase &PM) { PM.add(new LegacyBye()); });
+
 /* New PM Registration */
 llvm::PassPluginLibraryInfo getByePluginInfo() {
   return {LLVM_PLUGIN_API_VERSION, "Bye", LLVM_VERSION_STRING,