tor-browser

commit f9dd4b533df712f6ad101ee3f70d9042c86b8b66
parent 2e5bae3f1beee2be2beed977c85a4afa8f65d3a6
Author: Jan de Mooij <jdemooij@mozilla.com>
Date:   Sat, 13 Dec 2025 08:11:45 +0000

Bug 2005479 part 9 - Handle result_type: None in MIROps.yaml a bit better. r=iain

This shrinks the generated LIR a bit for the very small number of MIR instructions with
explicit `result_type: None` such as `GuardGlobalGeneration`.

Also don't generate a `setResultType(MIRType::None)` call for these cases.

Differential Revision: https://phabricator.services.mozilla.com/D276165

Diffstat:
M
js/src/jit/GenerateLIRFiles.py
 | 
4
+++-
M
js/src/jit/GenerateMIRFiles.py
 | 
4
+++-

2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/js/src/jit/GenerateLIRFiles.py b/js/src/jit/GenerateLIRFiles.py
@@ -392,6 +392,8 @@ class {class_name} : public {parent_class}<{num_defs}, {num_operands}, {num_temp
 
 
 def mir_type_to_lir_type(mir_type):
+    assert mir_type and mir_type != "None"
+
     if mir_type == "Value":
         return "BoxedValue"
 
@@ -491,7 +493,7 @@ def generate_lir_header(c_out, yaml_path, mir_yaml_path):
                     lir_result_type = None
                 else:
                     assert lir_result_type in result_types
-            elif result_type:
+            elif result_type and result_type != "None":
                 lir_result_type = mir_type_to_lir_type(result_type)
                 assert lir_result_type in result_types
 
diff --git a/js/src/jit/GenerateMIRFiles.py b/js/src/jit/GenerateMIRFiles.py
@@ -235,7 +235,9 @@ def gen_mir_class(
         code += "    setGuard();\\\n"
     if movable:
         code += "    setMovable();\\\n"
-    if result:
+    # Note: MIRType::None is the default MIR result type so don't generate a
+    # setResultType call for it.
+    if result and result != "None":
         code += f"    setResultType(MIRType::{result});\\\n"
     code += "  }\\\n public:\\\n"
     if arguments: