Add Support for Compiler Plugins

docs/source/user-guide/binding/optimization-passes.rst

@@ -68,6 +68,11 @@ create and configure a :class:`PassManagerBuilder`.
    methods or :meth:`PassManagerBuilder.populate` to add
    optimization passes.
 
+   * .. method:: add_pass_by_arg(arg)
+
+        Add a pass defined by the supplied ``arg``. See also :meth:`PassRegistry.list_registered_passes`.
+        Raises ``ValueError`` if no such pass is found.
+
    * .. function:: add_constant_merge_pass()
 
         See `constmerge pass documentation <http://llvm.org/docs/Passes.html#constmerge-merge-duplicate-global-constants>`_.
@@ -174,3 +179,19 @@ create and configure a :class:`PassManagerBuilder`.
 
         Returns ``True`` if the optimizations made any
         modification to the module. Otherwise returns ``False``.
+
+.. function:: load_pass_plugin(path)
+
+    Load a shared library defined by ``path`` which contains a custom
+    LLVM optimization path. See also `'Writing an LLVM Pass' <http://llvm.org/docs/WritingAnLLVMPass.html>`_.
+
+.. class:: PassRegistry()
+
+    This class represents the global pass registry for the available optimization passes.
+
+    * .. method:: list_registered_passes()
+
+        Returns the list of registered passes as a named tuple (arg, name).
+        ``arg`` is the unique identifier used to add passes with :meth:`PassManager.add_pass_by_arg`,
+        ``name`` is the human-readable name of the pass.
+        See also :func:`load_pass_plugin`.

ffi/CMakeLists.txt

@@ -27,6 +27,10 @@ add_definitions(${LLVM_DEFINITIONS})
 # Look for SVML
 set(CMAKE_REQUIRED_INCLUDES ${LLVM_INCLUDE_DIRS})
 
+if (NOT WIN32)
+    add_compile_options("-fno-rtti")
+endif()
+
 CHECK_INCLUDE_FILES("llvm/IR/SVML.inc" HAVE_SVML)
 if(HAVE_SVML)
     message(STATUS "SVML found")

ffi/Makefile.linux

@@ -1,9 +1,9 @@
 # Using g++ is recommended for linking
 CXX ?= g++
 
-# -flto and --exclude-libs allow us to remove those parts of LLVM we don't use
+# -flto allows us to remove those parts of LLVM we don't use
 CXX_FLTO_FLAGS ?= -flto
-LD_FLTO_FLAGS ?= -flto -Wl,--exclude-libs=ALL
+LD_FLTO_FLAGS ?= -flto
 # -fPIC is required when compiling objects for a shared library
 CXX_FPIC_FLAGS ?= -fPIC
 

ffi/passmanagers.cpp

@@ -13,6 +13,7 @@
 #include "llvm/Support/ToolOutputFile.h"
 #include "llvm/Support/YAMLTraits.h"
 #include "llvm/Support/raw_ostream.h"
+#include "llvm/ADT/SmallString.h"
 
 #include "llvm-c/Transforms/IPO.h"
 #include "llvm-c/Transforms/Scalar.h"
@@ -21,6 +22,8 @@
 #include "llvm/Remarks/RemarkStreamer.h"
 #include "llvm/Transforms/IPO.h"
 #include "llvm/Transforms/Scalar.h"
+#include "llvm/PassRegistry.h"
+#include "llvm/Pass.h"
 
 #include <llvm/IR/PassTimingInfo.h>
 
@@ -466,4 +469,52 @@ LLVMPY_LLVMAddLoopRotatePass(LLVMPassManagerRef PM) {
     LLVMAddLoopRotatePass(PM);
 }
 
+API_EXPORT(bool)
+LLVMPY_AddPassByArg(LLVMPassManagerRef PM, const char* passArg) {
+    auto passManager = llvm::unwrap(PM);
+    auto registry = PassRegistry::getPassRegistry();
+    const auto* passInfo = registry->getPassInfo(llvm::StringRef(passArg));
+    if (passInfo == nullptr) {
+        return false;
+    }
+    auto pass = passInfo->createPass();
+    passManager->add(pass);
+    return true;
+}
+
+namespace {
+class NameSavingPassRegListener : public llvm::PassRegistrationListener {
+  public:
+    NameSavingPassRegListener() : stream_buf_(), sstream_(stream_buf_) { }
+    void passEnumerate(const llvm::PassInfo* passInfo) override {
+        if (stream_buf_.size() != 0) {
+            sstream_ << ",";
+
+        }
+        sstream_ << passInfo->getPassArgument() << ":" << passInfo->getPassName();
+    }
+
+    const char* getNames() {
+        return stream_buf_.c_str();
+    }
+
+  private:
+    llvm::SmallString<128> stream_buf_;
+    llvm::raw_svector_ostream sstream_;
+};
+}
+
+API_EXPORT(LLVMPassRegistryRef)
+LLVMPY_GetPassRegistry() {
+    return LLVMGetGlobalPassRegistry();
+}
+
+API_EXPORT(void)
+LLVMPY_ListRegisteredPasses(LLVMPassRegistryRef PR, const char** out) {
+    auto registry = unwrap(PR);
+    auto listener = std::make_unique<NameSavingPassRegListener>();
+    registry->enumerateWith(listener.get());
+    *out = LLVMPY_CreateString(listener->getNames());
+}
+
 } // end extern "C"

llvmlite/binding/ffi.py

@@ -18,6 +18,7 @@ def _make_opaque_ref(name):
 LLVMExecutionEngineRef = _make_opaque_ref("LLVMExecutionEngine")
 LLVMPassManagerBuilderRef = _make_opaque_ref("LLVMPassManagerBuilder")
 LLVMPassManagerRef = _make_opaque_ref("LLVMPassManager")
+LLVMPassRegistryRef = _make_opaque_ref("LLVMPassRegistryRef")
 LLVMTargetDataRef = _make_opaque_ref("LLVMTargetData")
 LLVMTargetLibraryInfoRef = _make_opaque_ref("LLVMTargetLibraryInfo")
 LLVMTargetRef = _make_opaque_ref("LLVMTarget")

llvmlite/binding/passmanagers.py

@@ -1,4 +1,4 @@
-from ctypes import c_bool, c_char_p, c_int, c_size_t, c_uint, Structure, byref
+from ctypes import c_bool, c_char_p, c_int, c_size_t, c_uint, Structure, byref, cdll, POINTER
 from collections import namedtuple
 from enum import IntFlag
 from llvmlite.binding import ffi
@@ -100,10 +100,39 @@ class RefPruneSubpasses(IntFlag):
     ALL = PER_BB | DIAMOND | FANOUT | FANOUT_RAISE
 
 
+# Maintain a global list of loaded libraries.
+_loaded_libraries = []
+
+def load_pass_plugin(path):
+    """Load shared library containing a pass"""
+    pass_lib = cdll.LoadLibrary(path)
+    pass_lib.LLVMPY_RegisterPass(get_pass_registry())
+    _loaded_libraries.append(pass_lib)
+
+class PassRegistry(ffi.ObjectRef):
+    """
+        Return the names of the registered passes as a list
+        of tuples (<pass arg>, <pass name>)
+    """
+    def list_registered_passes(self):
+        PassInfo = namedtuple("PassInfo", ["arg", "name"])
+        with ffi.OutputString() as out:
+            ffi.lib.LLVMPY_ListRegisteredPasses(self, out)
+            passes = [PassInfo(*pass_info.split(":", 1)) \
+                      for pass_info in str(out).split(',')]
+            return passes
+
+def get_pass_registry():
+    return PassRegistry(ffi.lib.LLVMPY_GetPassRegistry())
+
+
 class PassManager(ffi.ObjectRef):
     """PassManager
     """
 
+    def __init__(self, ptr):
+        super(PassManager, self).__init__(ptr)
+
     def _dispose(self):
         self._capi.LLVMPY_DisposePassManager(self)
 
@@ -131,6 +160,11 @@ def add_constant_merge_pass(self):
         """  # noqa E501
         ffi.lib.LLVMPY_AddConstantMergePass(self)
 
+    def add_pass_by_arg(self, pass_arg):
+        """Add a pass using its registered name"""
+        if not ffi.lib.LLVMPY_AddPassByArg(self, pass_arg.encode("utf8")):
+            raise ValueError("Could not add pass '{}'".format(pass_arg))
+
     def add_dead_arg_elimination_pass(self):
         """
         See http://llvm.org/docs/Passes.html#deadargelim-dead-argument-elimination
@@ -914,3 +948,9 @@ def run_with_remarks(self, function, remarks_format='yaml',
 
 ffi.lib.LLVMPY_AddRefPrunePass.argtypes = [ffi.LLVMPassManagerRef, c_int,
                                            c_size_t]
+
+ffi.lib.LLVMPY_GetPassRegistry.argtypes = []
+ffi.lib.LLVMPY_GetPassRegistry.restype = ffi.LLVMPassRegistryRef
+ffi.lib.LLVMPY_ListRegisteredPasses.argtypes = [ffi.LLVMPassRegistryRef, POINTER(c_char_p)]
+ffi.lib.LLVMPY_AddPassByArg.argtypes = [ffi.LLVMPassManagerRef, c_char_p]
+ffi.lib.LLVMPY_AddPassByArg.restype = c_bool