Allow external CodeInstances to be added to the execution engine

As of #35831, we've had the ability to cache CodeInstances in an
external cache and to replace that cache during jl_generate_native
(e.g. for GPU compilation). This extends the same capability to
CodeInstances to be added to the execution engine.

src/jitlayers.cpp

@@ -81,15 +81,16 @@ void jl_jit_strings(jl_codegen_params_t::SymMapGV &stringConstants)
  }
 }
 
-
 // this generates llvm code for the lambda info
 // and adds the result to the jitlayers
 // (and the shadow module),
 // and generates code for it
-static jl_callptr_t _jl_compile_codeinst(
+extern "C" {
+JL_DLLEXPORT jl_callptr_t jl_compile_codeinst(
  jl_code_instance_t *codeinst,
  jl_code_info_t *src,
- size_t world)
+ size_t world,
+ const jl_cgparams_t *cg_params)
 {
  // TODO: Merge with jl_dump_compiles?
  static ios_t f_precompile;
@@ -111,6 +112,7 @@ static jl_callptr_t _jl_compile_codeinst(
  jl_codegen_params_t params;
  params.cache = true;
  params.world = world;
+ params.params = cg_params;
  std::map<jl_code_instance_t*, jl_compile_result_t> emitted;
  {
  JL_TIMING(CODEGEN);
@@ -218,6 +220,15 @@ static jl_callptr_t _jl_compile_codeinst(
  }
  return fptr;
 }
+}
+
+static jl_callptr_t _jl_compile_codeinst(
+ jl_code_instance_t *codeinst,
+ jl_code_info_t *src,
+ size_t world)
+{
+ return jl_compile_codeinst(codeinst, src, world, &jl_default_cgparams);
+}
 
 void jl_generate_ccallable(void *llvmmod, void *sysimg_handle, jl_value_t *declrt, jl_value_t *sigt, jl_codegen_params_t &params);