Give JIT intrinsics the jit-no-gc calling convention

kernel/modelverse_jit/cfg_ir.py

@@ -473,6 +473,9 @@ SELF_POSITIONAL_CALLING_CONVENTION = 'self-positional'
 JIT_CALLING_CONVENTION = 'jit'
 """The calling convention for jitted functions."""
 
+JIT_NO_GC_CALLING_CONVENTION = 'jit-no-gc'
+"""The calling convention for jitted functions that promise not to initiate a GC cycle."""
+
 MACRO_POSITIONAL_CALLING_CONVENTION = 'macro-positional'
 """The calling convention for well-known functions that are expanded as macros during codegen."""
 

kernel/modelverse_jit/cfg_optimization.py

@@ -240,9 +240,13 @@ def try_redefine_as_direct_call(definition, jit, called_globals):
             else:
                 # Otherwise, build a thunk.
                 thunk_name = jit.jit_thunk_global(resolved_var_name)
+                calling_convention = (
+                    cfg_ir.JIT_NO_GC_CALLING_CONVENTION
+                    if jit.get_intrinsic(thunk_name) is not None
+                    else cfg_ir.JIT_CALLING_CONVENTION)
                 definition.redefine(
                     cfg_ir.DirectFunctionCall(
-                        thunk_name, call.argument_list, cfg_ir.JIT_CALLING_CONVENTION))
+                        thunk_name, call.argument_list, calling_convention))
                 called_globals.add(loaded_ptr)
     elif isinstance(target, cfg_ir.Literal):
         node_id = target.literal
@@ -384,6 +388,7 @@ def protect_from_gc(entry_point):
             elif (isinstance(def_value, cfg_ir.IndirectFunctionCall)
                   or (isinstance(def_value, cfg_ir.DirectFunctionCall)
                       and (def_value.calling_convention == cfg_ir.JIT_CALLING_CONVENTION
+                           or def_value.calling_convention == cfg_ir.JIT_NO_GC_CALLING_CONVENTION
                            or def_value.calling_convention == cfg_ir.MACRO_IO_CALLING_CONVENTION)
                       and def_value.has_value())):
                 maybe_protect_def_from_gc(definition)

kernel/modelverse_jit/cfg_to_tree.py

@@ -971,6 +971,7 @@ class LoweringState(object):
         cfg_ir.SIMPLE_POSITIONAL_CALLING_CONVENTION : lower_simple_positional_call,
         cfg_ir.SELF_POSITIONAL_CALLING_CONVENTION : lower_self_positional_call,
         cfg_ir.JIT_CALLING_CONVENTION : lower_jit_call,
+        cfg_ir.JIT_NO_GC_CALLING_CONVENTION : lower_jit_call,
         cfg_ir.MACRO_POSITIONAL_CALLING_CONVENTION : lower_macro_call,
         cfg_ir.MACRO_IO_CALLING_CONVENTION : lower_io_call
     }