[clang] [lld] [llvm] [RFC] Initial reference pass-plugin in LLVM (PR #171111)

[via llvm-commits]

================
@@ -0,0 +1,464 @@
+//===- tools/plugins-shlib/pypass.cpp -------------------------------------===//
+//
+// 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 "llvm/ADT/ScopeExit.h"
+#include "llvm/Passes/PassBuilder.h"
+#include "llvm/Passes/PassPlugin.h"
+#include "llvm/Support/DynamicLibrary.h"
+#include "llvm/Support/raw_ostream.h"
+
+#include <algorithm>
+#include <cstdlib>
+#include <filesystem>
+#include <memory>
+#include <optional>
+#include <string>
+
+using namespace llvm;
+
+static cl::opt<std::string>
+    DylibPath("pypass-dylib", cl::desc("Path to the Python shared library"),
+              cl::init(""));
+
+static cl::opt<std::string>
+    ScriptPath("pypass-script", cl::desc("Path to the Python script to run"),
+               cl::init(""));
+
+static std::string findPython() {
+  if (!DylibPath.empty())
+    return DylibPath;
+  if (const char *Path = std::getenv("LLVM_PYPASS_DYLIB"))
+    return std::string(Path);
+  // TODO: Run Python from PATH and use a script to query the shared lib
+  return std::string{};
+}
+
+static std::string findScript() {
+  if (!ScriptPath.empty())
+    return ScriptPath;
+  if (const char *Path = std::getenv("LLVM_PYPASS_SCRIPT"))
+    return std::string(Path);
+  return std::string{};
+}
+
+struct PythonAPI {
+  using Py_InitializeEx_t = void(int);
+  using Py_Initialize_t = void(void);
+  using Py_FinalizeEx_t = int(void);
+  using Py_Finalize_t = void(void);
+  using PyDict_GetItemString_t = void *(void *, const char *);
+  using PyGILStateEnsure_t = int();
+  using PyGILStateRelease_t = void(int);
+  using PyImport_AddModule_t = void *(const char *);
+  using PyLong_FromVoidPtr_t = void *(void *);
+  using PyUnicode_FromString_t = void *(const char *);
+  using PyModule_GetDict_t = void *(void *);
+  using PyObject_CallObject_t = void *(void *, void *);
+  using PyObject_IsTrue_t = int(void *);
+  using PyRun_SimpleString_t = int(const char *);
+  using PyTuple_SetItem_t = int(void *, long, void *);
+  using PyTuple_New_t = void *(long);
+  using PyTypeObject_t = void *;
+
+  // pylifecycle.h
+  Py_InitializeEx_t *Py_InitializeEx;
+  Py_Initialize_t *Py_Initialize;
+  Py_FinalizeEx_t *Py_FinalizeEx;
+  Py_Finalize_t *Py_Finalize;
+
+  // pythonrun.h
+  PyRun_SimpleString_t *PyRun_SimpleString;
+
+  // pystate.h
+  PyGILStateEnsure_t *PyGILState_Ensure;
+  PyGILStateRelease_t *PyGILState_Release;
+
+  // import.h
+  PyImport_AddModule_t *PyImport_AddModule;
+
+  // object.h
+  PyObject_IsTrue_t *PyObject_IsTrue;
+
+  // moduleobject.h
+  PyModule_GetDict_t *PyModule_GetDict;
+
+  // dictobject.h
+  PyDict_GetItemString_t *PyDict_GetItemString;
+
+  // abstract.h
+  PyObject_CallObject_t *PyObject_CallObject;
+
+  // longobject.h
+  PyLong_FromVoidPtr_t *PyLong_FromVoidPtr;
+
+  // unicodeobject.h
+  PyUnicode_FromString_t *PyUnicode_FromString;
+
+  // tupleobject.h
+  PyTuple_SetItem_t *PyTuple_SetItem;
+  PyTuple_New_t *PyTuple_New;
+
+  PythonAPI() : Ready(false) {
+    if (!loadDylib(findPython()))
+      return;
+    if (!resolveSymbols())
+      return;
+    if (Py_InitializeEx) {
----------------
serge-sans-paille wrote:

Can this happen? It's part of the stable API, and `resolve_symbols` would return `False` if this fails, right?

https://github.com/llvm/llvm-project/pull/171111