Find c++ exception handling runtime in our own _runtime.cpp instead of libstdc++.

In particular, this makes it easier to run our code on platforms where we don't know
where to look to find libstdc++.  setup.py knows where this is and links us to it anyways.

Author: braxtonmckee

typed_python/_runtime.cpp

@@ -52,6 +52,38 @@ PyObject* getRuntimeSingleton() {
 // Note: extern C identifiers are distinguished only up to 32 characters
 // nativepython_runtime_12345678901
 extern "C" {
+    /******************************
+    these are exception-handling routines. rather than trying to find the c++ standard library
+    and linking to them in the python llvm wrapper, we can just passthrough to them directly
+    from here, since we're definitely linked into them anyways.
+    *******************************/
+
+    //forward declarations
+    void* __cxa_allocate_exception(long unsigned int i);
+    void __cxa_throw(void* a, void* b, void (*c)(void*));
+    void __cxa_end_catch();
+    void* __cxa_begin_catch(void* a);
+    void __gxx_personality_v0();
+
+    void* tp_cxa_allocate_exception(int64_t i) {
+        return __cxa_allocate_exception(i);
+    }
+    void tp_cxa_throw(void* a, void* b, void (*c)(void*)) {
+        __cxa_throw(a, b, c);
+    }
+    void* tp_cxa_end_catch(void* a) {
+        __cxa_end_catch();
+        return (void*)nullptr;
+    }
+    void* tp_cxa_begin_catch(void* a) {
+        return __cxa_begin_catch(a);
+    }
+
+    void tp_gxx_personality_v0() {
+        __gxx_personality_v0();
+    }
+    /******************************/
+
     void np_compileClassDispatch(ClassDispatchTable* classDispatchTable, int slot) {
         PyEnsureGilAcquired getTheGil;
 

typed_python/compiler/llvm_compiler.py

@@ -21,7 +21,6 @@
 from typed_python.compiler.native_function_pointer import NativeFunctionPointer
 from typed_python.compiler.binary_shared_object import BinarySharedObject
 
-import sys
 import ctypes
 from typed_python import _types
 
@@ -34,12 +33,6 @@
 target_machine = target.create_target_machine()
 target_machine_shared_object = target.create_target_machine(reloc='pic', codemodel='default')
 
-# we need to load the appropriate libstdc++ so that we can get __cxa_begin_catch and friends
-if sys.platform == "darwin":
-    ctypes.CDLL("libstdc++.dylib", mode=ctypes.RTLD_GLOBAL)
-else:
-    ctypes.CDLL("libstdc++.so.6", mode=ctypes.RTLD_GLOBAL)
-
 ctypes.CDLL(_types.__file__, mode=ctypes.RTLD_GLOBAL)
 
 

typed_python/compiler/native_ast_to_llvm.py

@@ -565,7 +565,7 @@ def generate_exception_landing_pad(self, block):
             )
 
             actual_exception = self.builder.call(
-                self.external_function_references["__cxa_begin_catch"],
+                self.external_function_references["tp_cxa_begin_catch"],
                 [self.builder.extract_value(res, 0)]
             )
 
@@ -579,7 +579,7 @@ def generate_exception_landing_pad(self, block):
             self.builder.store(result, self.exception_slot)
 
             self.builder.call(
-                self.external_function_references["__cxa_end_catch"],
+                self.external_function_references["tp_cxa_end_catch"],
                 [self.builder.extract_value(res, 0)]
             )
 
@@ -619,7 +619,7 @@ def convert_teardown(self, teardown, justClearTags=False):
     def generate_exception_and_store_value(self, llvm_pointer_val):
         exception_ptr = self.builder.bitcast(
             self.builder.call(
-                self.external_function_references["__cxa_allocate_exception"],
+                self.external_function_references["tp_cxa_allocate_exception"],
                 [llvmI64(pointer_size)],
                 name="alloc_e"
             ),
@@ -696,7 +696,7 @@ def generate_throw_expression(self, llvm_pointer_val):
         exception_ptr = self.generate_exception_and_store_value(llvm_pointer_val)
 
         self.builder.call(
-            self.external_function_references["__cxa_throw"],
+            self.external_function_references["tp_cxa_throw"],
             [exception_ptr] + [llvmlite.ir.Constant(llvm_i8ptr, None)] * 2
         )
 
@@ -1474,11 +1474,11 @@ def define(fname, output, inputs, vararg=False):
                 ),
                 fname
         )
-    define("__cxa_allocate_exception", llvm_i8ptr, [llvm_i64])
-    define("__cxa_throw", llvm_void, [llvm_i8ptr, llvm_i8ptr, llvm_i8ptr])
-    define("__cxa_end_catch", llvm_i8ptr, [llvm_i8ptr])
-    define("__cxa_begin_catch", llvm_i8ptr, [llvm_i8ptr])
-    define("__gxx_personality_v0", llvm_i32, [], vararg=True)
+    define("tp_cxa_allocate_exception", llvm_i8ptr, [llvm_i64])
+    define("tp_cxa_throw", llvm_void, [llvm_i8ptr, llvm_i8ptr, llvm_i8ptr])
+    define("tp_cxa_end_catch", llvm_i8ptr, [llvm_i8ptr])
+    define("tp_cxa_begin_catch", llvm_i8ptr, [llvm_i8ptr])
+    define("tp_gxx_personality_v0", llvm_void, [])
 
 
 class Converter:
@@ -1607,7 +1607,7 @@ def add_functions(self, names_to_definitions):
             for name in sorted(names_to_definitions):
                 definition = names_to_definitions.pop(name)
                 func = self._functions_by_name[name]
-                func.attributes.personality = external_function_references["__gxx_personality_v0"]
+                func.attributes.personality = external_function_references["tp_gxx_personality_v0"]
 
                 # for a in func.args:
                 #     if a.type.is_pointer: