Compiler extension patch

Author: serge-sans-paille

llvm/cmake/modules/AddLLVM.cmake

@@ -847,32 +847,40 @@ macro(add_llvm_executable name)
   llvm_codesign(${name} ENTITLEMENTS ${ARG_ENTITLEMENTS} BUNDLE_PATH ${ARG_BUNDLE_PATH})
 endmacro(add_llvm_executable name)
 
-# add_llvm_pass_plugin(name)
+# add_llvm_pass_plugin(name [NO_MODULE] ...)
 #   Add ${name} as an llvm plugin.
 #   If option LLVM_${name_upper}_LINK_INTO_TOOLS is set to ON, the plugin is registered statically.
 #   Otherwise a pluggable shared library is registered.
+#
+#   If NO_MODULE is specified, when option LLVM_${name_upper}_LINK_INTO_TOOLS is set to OFF,
+#   only an object library is built, and no module is built. This is specific to the Polly use case.
 function(add_llvm_pass_plugin name)
+  cmake_parse_arguments(ARG
+    "NO_MODULE" "" ""
+    ${ARGN})
 
   string(TOUPPER ${name} name_upper)
 
   option(LLVM_${name_upper}_LINK_INTO_TOOLS "Statically link ${name} into tools (if available)" OFF)
 
-  # process_llvm_pass_plugins takes care of the actual linking, just create an
-  # object library as of now
-  add_llvm_library(${name} OBJECT ${ARGN})
-
-  if(LLVM_${name_upper}_LINK_INTO_TOOLS)
-      target_compile_definitions(${name} PRIVATE LLVM_${name_upper}_LINK_INTO_TOOLS)
-      set_property(TARGET ${name} APPEND PROPERTY COMPILE_DEFINITIONS LLVM_LINK_INTO_TOOLS)
-      if (TARGET intrinsics_gen)
-        add_dependencies(obj.${name} intrinsics_gen)
-      endif()
-  endif()
-
-  message(STATUS "Registering ${name} as a pass plugin (static build: ${LLVM_${name_upper}_LINK_INTO_TOOLS})")
   if(LLVM_${name_upper}_LINK_INTO_TOOLS)
+    list(REMOVE_ITEM ARG_UNPARSED_ARGUMENTS BUILDTREE_ONLY)
+    # process_llvm_pass_plugins takes care of the actual linking, just create an
+    # object library as of now
+    add_llvm_library(${name} OBJECT ${ARG_UNPARSED_ARGUMENTS})
+    target_compile_definitions(${name} PRIVATE LLVM_${name_upper}_LINK_INTO_TOOLS)
+    set_property(TARGET ${name} APPEND PROPERTY COMPILE_DEFINITIONS LLVM_LINK_INTO_TOOLS)
+    if (TARGET intrinsics_gen)
+      add_dependencies(obj.${name} intrinsics_gen)
+    endif()
+    message(STATUS "Registering ${name} as a pass plugin (static build: ${LLVM_${name_upper}_LINK_INTO_TOOLS})")
     set_property(GLOBAL APPEND PROPERTY LLVM_COMPILE_EXTENSIONS ${name})
+  elseif(NOT ARG_NO_MODULE)
+    add_llvm_library(${name} MODULE ${ARG_UNPARSED_ARGUMENTS})
+  else()
+    add_llvm_library(${name} OBJECT ${ARG_UNPARSED_ARGUMENTS})
   endif()
+
 endfunction(add_llvm_pass_plugin)
 
 # Generate X Macro file for extension handling. It provides a

llvm/examples/Bye/CMakeLists.txt

@@ -1,23 +1,13 @@
-add_llvm_pass_plugin(Bye
-    Bye.cpp
-    DEPENDS
-    intrinsics_gen
-    BUILDTREE_ONLY
-    )
-
-if (LLVM_LINK_LLVM_DYLIB)
-  target_link_libraries(Bye PUBLIC LLVM)
-else()
-  target_link_libraries(Bye
-    PUBLIC
-    LLVMSupport
-    LLVMCore
-    LLVMipo
-    LLVMPasses
-    )
+if(LLVM_BYE_LINK_INTO_TOOLS)
+  message(WARNING "Setting LLVM_BYE_LINK_INTO_TOOLS=ON only makes sense for testing purpose")
 endif()
 
-if( LLVM_BUILD_EXAMPLES )
-  install(TARGETS ${name} RUNTIME DESTINATION examples)
-endif()
+add_llvm_pass_plugin(Bye
+  Bye.cpp
+  DEPENDS
+  intrinsics_gen
+  BUILDTREE_ONLY
+ )
+
+install(TARGETS ${name} RUNTIME DESTINATION examples)
 set_target_properties(${name} PROPERTIES FOLDER "Examples")

llvm/include/llvm/Support/DynamicLibrary.h

@@ -123,6 +123,10 @@ namespace sys {
     /// Add searchable symbol/value pair.
     static void AddSymbol(StringRef symbolName, void *symbolValue);
 
+    /// Ensure the underlying library registry is properly constructed.
+    /// This is only useful to force ManagedStatic registration ordering.
+    static void ensureConstructed();
+
     class HandleSet;
   };
 

llvm/lib/Support/DynamicLibrary.cpp

@@ -145,6 +145,11 @@ void DynamicLibrary::AddSymbol(StringRef SymbolName, void *SymbolValue) {
   (*ExplicitSymbols)[SymbolName] = SymbolValue;
 }
 
+void DynamicLibrary::ensureConstructed() {
+  (void)*OpenedHandles;
+}
+
+
 DynamicLibrary DynamicLibrary::getPermanentLibrary(const char *FileName,
                                                    std::string *Err) {
   // Force OpenedHandles to be added into the ManagedStatic list before any

llvm/lib/Transforms/IPO/PassManagerBuilder.cpp

@@ -27,6 +27,7 @@
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/Verifier.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Support/DynamicLibrary.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Transforms/AggressiveInstCombine/AggressiveInstCombine.h"
 #include "llvm/Transforms/IPO.h"
@@ -194,12 +195,20 @@ static ManagedStatic<SmallVector<std::pair<PassManagerBuilder::ExtensionPointTy,
 /// Since GlobalExtensions is a managed static, calling 'empty()' will trigger
 /// the construction of the object.
 static bool GlobalExtensionsNotEmpty() {
+  // Dynamic library static registry **must** be initialized before global
+  // extension registry, because global extension may reference functions from
+  // dynamically opened libraries. Failing to ensure that order (randomly)
+  // triggers a segfault upon destruction, if the dynamically loaded library is
+  // closed before the global extensions are destroyed.
+  sys::DynamicLibrary::ensureConstructed();
   return GlobalExtensions.isConstructed() && !GlobalExtensions->empty();
 }
 
 void PassManagerBuilder::addGlobalExtension(
     PassManagerBuilder::ExtensionPointTy Ty,
     PassManagerBuilder::ExtensionFn Fn) {
+  // See comment in GlobalExtensionsNotEmpty
+  sys::DynamicLibrary::ensureConstructed();
   GlobalExtensions->push_back(std::make_pair(Ty, std::move(Fn)));
 }
 

llvm/test/Feature/load_extension.ll

@@ -1,8 +1,5 @@
-; This is currently failing on multiple platforms. Disable while investigation occurs.
-; XFAIL: *
-
 ; RUN: opt %s %loadbye -goodbye -wave-goodbye -disable-output 2>&1 | FileCheck %s
-; REQUIRES: plugins, examples
+; REQUIRES: plugins
 ; CHECK: Bye
 
 @junk = global i32 0

llvm/test/lit.cfg.py

@@ -200,13 +200,13 @@ def get_asan_rtlib():
 if config.build_examples:
     config.available_features.add('examples')
 
-if config.linked_bye_extension and config.build_examples:
+if config.linked_bye_extension:
     config.substitutions.append(('%llvmcheckext', 'CHECK-EXT'))
     config.substitutions.append(('%loadbye', ''))
 else:
     config.substitutions.append(('%llvmcheckext', 'CHECK-NOEXT'))
     config.substitutions.append(('%loadbye',
-                                 '-load={}/libBye{}'.format(config.llvm_shlib_dir,
+                                 '-load={}/Bye{}'.format(config.llvm_shlib_dir,
                                                                   config.llvm_shlib_ext)))
 
 # Static libraries are not built if BUILD_SHARED_LIBS is ON.

polly/lib/CMakeLists.txt

@@ -24,6 +24,7 @@ endif ()
 # Use an object-library to add the same files to multiple libs without requiring
 # the sources them to be recompiled for each of them.
 add_llvm_pass_plugin(Polly
+  NO_MODULE
   Analysis/DependenceInfo.cpp
   Analysis/PolyhedralInfo.cpp
   Analysis/ScopDetection.cpp