1 files changed, 65 insertions, 0 deletions
diff --git a/contrib/llvm-project/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.cpp b/contrib/llvm-project/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.cpp
new file mode 100644
index 000000000000..3cbd3b5efecc
--- /dev/null
+++ b/contrib/llvm-project/lldb/source/Plugins/ScriptInterpreter/Python/PythonReadline.cpp
@@ -0,0 +1,65 @@
+#include "PythonReadline.h"
+
+#ifdef LLDB_USE_LIBEDIT_READLINE_COMPAT_MODULE
+
+#include <cstdio>
+
+#include <editline/readline.h>
+
+// Simple implementation of the Python readline module using libedit.
+// In the event that libedit is excluded from the build, this turns
+// back into a null implementation that blocks the module from pulling
+// in the GNU readline shared lib, which causes linkage confusion when
+// both readline and libedit's readline compatibility symbols collide.
+//
+// Currently it only installs a PyOS_ReadlineFunctionPointer, without
+// implementing any of the readline module methods. This is meant to
+// work around LLVM pr18841 to avoid seg faults in the stock Python
+// readline.so linked against GNU readline.
+//
+// Bug on the cpython side: https://bugs.python.org/issue38634
+
+PyDoc_STRVAR(moduleDocumentation,
+             "Simple readline module implementation based on libedit.");
+
+static struct PyModuleDef readline_module = {
+    PyModuleDef_HEAD_INIT, // m_base
+    "lldb_editline",       // m_name
+    moduleDocumentation,   // m_doc
+    -1,                    // m_size
+    nullptr,               // m_methods
+    nullptr,               // m_reload
+    nullptr,               // m_traverse
+    nullptr,               // m_clear
+    nullptr,               // m_free
+};
+
+static char *simple_readline(FILE *stdin, FILE *stdout, const char *prompt) {
+  rl_instream = stdin;
+  rl_outstream = stdout;
+  char *line = readline(prompt);
+  if (!line) {
+    char *ret = (char *)PyMem_RawMalloc(1);
+    if (ret != nullptr)
+      *ret = '\0';
+    return ret;
+  }
+  if (*line)
+    add_history(line);
+  int n = strlen(line);
+  char *ret = (char *)PyMem_RawMalloc(n + 2);
+  if (ret) {
+    memcpy(ret, line, n);
+    free(line);
+    ret[n] = '\n';
+    ret[n + 1] = '\0';
+  }
+  return ret;
+}
+
+PyMODINIT_FUNC initlldb_readline(void) {
+  PyOS_ReadlineFunctionPointer = simple_readline;
+
+  return PyModule_Create(&readline_module);
+}
+#endif