don't override line info when code generation gives it explicitly (Ju…

…liaLang#47750)

* respect given line info when code generation produces `CodeInfo`

This should improve a readability of stacktrace for code generated by
Cassette-like mechanism that produces `CodeInfo` from `@generated`
function.

* add test

src/method.c

@@ -504,7 +504,10 @@ void jl_add_function_name_to_lineinfo(jl_code_info_t *ci, jl_value_t *name)
  jl_value_t *file = jl_fieldref_noalloc(ln, 2);
  lno = jl_fieldref(ln, 3);
  inl = jl_fieldref(ln, 4);
- jl_value_t *ln_name = (jl_is_int32(inl) && jl_unbox_int32(inl) == 0) ? name : jl_fieldref_noalloc(ln, 1);
+ // respect a given linetable if available
+ jl_value_t *ln_name = jl_fieldref_noalloc(ln, 1);
+ if (jl_is_symbol(ln_name) && (jl_sym_t*)ln_name == jl_symbol("none") && jl_is_int32(inl) && jl_unbox_int32(inl) == 0)
+ ln_name = name;
  rt = jl_new_struct(jl_lineinfonode_type, mod, ln_name, file, lno, inl);
  jl_array_ptr_set(li, i, rt);
  }
@@ -587,7 +590,6 @@ JL_DLLEXPORT jl_code_info_t *jl_code_for_staged(jl_method_instance_t *linfo)
  else {
  // Lower the user's expression and resolve references to the type parameters
  func = jl_expand_and_resolve(ex, def->module, linfo->sparam_vals);
-
  if (!jl_is_code_info(func)) {
  if (jl_is_expr(func) && ((jl_expr_t*)func)->head == jl_error_sym) {
  ct->ptls->in_pure_callback = 0;

test/staged.jl

@@ -320,3 +320,15 @@ let tup = g_vararg_generated()
  # shifts everything over by 1)
  @test only(code_lowered(only(methods(f_vararg_generated)).generator.gen)).slotflags[5] == UInt8(0x00)
 end
+
+# respect a given linetable in code generation
+# https://github.com/JuliaLang/julia/pull/47750
+let match = Base._which(Tuple{typeof(sin),Int})
+ mi = Core.Compiler.specialize_method(match)
+ lwr = Core.Compiler.retrieve_code_info(mi)
+ @test all(lin->lin.method===:sin, lwr.linetable)
+ @generated sin_generated(a) = lwr
+ src = only(code_lowered(sin_generated, (Int,)))
+ @test all(lin->lin.method===:sin, src.linetable)
+ @test sin_generated(42) == sin(42)
+end