Get rid of void-returning functions

Module-level code used to return void, but this causes some
special-casing, so switch to having them return None.
Also, CPython has their module code objects return None, so
it's a small compatibility gain as well.

src/codegen/ast_interpreter.cpp

@@ -781,13 +781,8 @@ Box* ASTInterpreter::doOSR(AST_Jump* node) {
     Box* r = partial_func->call(std::get<0>(arg_tuple), std::get<1>(arg_tuple), std::get<2>(arg_tuple),
                                 std::get<3>(arg_tuple));
 
-    // This is one of the few times that we are allowed to have an invalid value in a Box* Value.
-    // Check for it, and return as an int so that we don't trigger a potential assert when
-    // creating the Value.
-    if (compiled_func->getReturnType() != VOID)
     assert(r);
-
-    return r ? r : None;
+    return r;
 }
 
 Value ASTInterpreter::visit_invoke(AST_Invoke* node) {

src/codegen/compvars.cpp

@@ -1965,14 +1965,6 @@ CompilerVariable* makeStr(BoxedString* s) {
     return new ValuedCompilerVariable<BoxedString*>(STR_CONSTANT, s, true);
 }
 
-class VoidType : public ConcreteCompilerType {
-public:
-    llvm::Type* llvmType() override { return g.void_; }
-
-    Box* deserializeFromFrame(const FrameVals& vals) override { abort(); }
-};
-ConcreteCompilerType* VOID = new VoidType();
-
 ConcreteCompilerType* typeFromClass(BoxedClass* c) {
     assert(c);
     return NormalObjectType::fromClass(c);

src/codegen/irgen.cpp

@@ -579,11 +579,7 @@ static void emitBBs(IRGenState* irstate, TypeAnalysis* types, const OSREntryDesc
                 // printf("%ld\n", args.size());
                 llvm::CallInst* postcall = emitter->getBuilder()->CreateCall(bitcast_r, args);
                 postcall->setTailCall(true);
-                if (rtn_type == VOID) {
-                    emitter->getBuilder()->CreateRetVoid();
-                } else {
                 emitter->getBuilder()->CreateRet(postcall);
-                }
 
                 emitter->getBuilder()->SetInsertPoint(llvm_entry_blocks[source->cfg->getStartingBlock()]);
             }

src/codegen/irgen/hooks.cpp

@@ -323,7 +323,7 @@ void compileAndRunModule(AST_Module* m, BoxedModule* bm) {
 
         assert(scoping->areGlobalsFromModule());
 
-        cf = compileFunction(cl_f, new FunctionSpecialization(VOID), effort, NULL);
+        cf = compileFunction(cl_f, new FunctionSpecialization(NONE), effort, NULL);
         assert(cf->clfunc->versions.size());
     }
 
@@ -355,7 +355,7 @@ Box* evalOrExec(CLFunction* cl, Box* globals, Box* boxedLocals) {
         setGlobal(boxedLocals, doc_box, doc_string);
     }
 
-    CompiledFunction* cf = compileFunction(cl, new FunctionSpecialization(VOID), effort, NULL);
+    CompiledFunction* cf = compileFunction(cl, new FunctionSpecialization(NONE), effort, NULL);
     assert(cf->clfunc->versions.size());
 
     return astInterpretFunctionEval(cf, globals, boxedLocals);

src/codegen/irgen/irgenerator.cpp

@@ -531,9 +531,6 @@ private:
         emitter.getBuilder()->SetInsertPoint(curblock);
         llvm::Value* v = emitter.createCall2(UnwindInfo(current_statement, NULL), g.funcs.deopt,
                                              embedRelocatablePtr(node, g.llvm_aststmt_type_ptr), node_value);
-        if (irstate->getReturnType() == VOID)
-            emitter.getBuilder()->CreateRetVoid();
-        else
         emitter.getBuilder()->CreateRet(v);
 
         curblock = success_bb;
@@ -1955,12 +1952,6 @@ private:
 
         CompilerVariable* val;
         if (node->value == NULL) {
-            if (irstate->getReturnType() == VOID) {
-                endBlock(DEAD);
-                emitter.getBuilder()->CreateRetVoid();
-                return;
-            }
-
             val = getNone();
         } else {
             val = evalExpr(node->value, unw_info);
@@ -2185,9 +2176,6 @@ private:
             converted_args[i]->decvref(emitter);
         }
 
-        if (irstate->getReturnType() == VOID)
-            emitter.getBuilder()->CreateRetVoid();
-        else
         emitter.getBuilder()->CreateRet(rtn);
 
         emitter.getBuilder()->SetInsertPoint(starting_block);

src/core/types.h

@@ -74,8 +74,8 @@ template <class V> class ValuedCompilerType;
 typedef ValuedCompilerType<llvm::Value*> ConcreteCompilerType;
 ConcreteCompilerType* typeFromClass(BoxedClass*);
 
-extern ConcreteCompilerType* INT, *BOXED_INT, *LONG, *FLOAT, *BOXED_FLOAT, *VOID, *UNKNOWN, *BOOL, *STR, *NONE, *LIST,
-    *SLICE, *MODULE, *DICT, *BOOL, *BOXED_BOOL, *BOXED_TUPLE, *SET, *FROZENSET, *CLOSURE, *GENERATOR, *BOXED_COMPLEX,
+extern ConcreteCompilerType* INT, *BOXED_INT, *LONG, *FLOAT, *BOXED_FLOAT, *UNKNOWN, *BOOL, *STR, *NONE, *LIST, *SLICE,
+    *MODULE, *DICT, *BOOL, *BOXED_BOOL, *BOXED_TUPLE, *SET, *FROZENSET, *CLOSURE, *GENERATOR, *BOXED_COMPLEX,
     *FRAME_INFO;
 extern CompilerType* UNDEF;