speccpu/x264: add x264 mc src, add printf to weight->i_scale

src/speccpu/x264.py

@@ -1,3 +1,4 @@
+import importlib.resources
 import os
 import shutil
 from pathlib import Path
@@ -8,6 +9,49 @@ def get_mc_path(build):
     return build / "x264_src" / "common" / "mc.c"
 
 
+class MCBuilder:
+    @staticmethod
+    def get_src():
+        assert __package__ is not None
+        with importlib.resources.open_text(__package__, "mc.c") as f:
+            mc_src = f.read()
+        return mc_src
+
+    def __init__(self):
+        self.mc_src = self.get_src()
+
+    def with_print_weight(self):
+        """
+        Insert a printf statement after the opening brace in the mc_weight function.
+        """
+        target_declaration = "static inline void mc_weight"
+        printf_statement = '    printf("weight->i_scale = %d\\n", weight->i_scale);'
+
+        # Find the position of the target function declaration
+        start_index = self.mc_src.find(target_declaration)
+        if start_index == -1:
+            raise ValueError("Could not find target function `mc_weight`")
+
+        # Find the position of the opening brace { after the target function declaration
+        open_brace_index = self.mc_src.find("{", start_index)
+        if open_brace_index == -1:
+            raise ValueError("Could not find opening brace { for the target function")
+
+        # Insert printf statement after the opening brace
+        self.mc_src = (
+            self.mc_src[: open_brace_index + 1]  # Original content up to {
+            + "\n"
+            + printf_statement  # Insert printf statement
+            + "\n"
+            + self.mc_src[open_brace_index + 1 :]  # Remaining content
+        )
+
+        return self
+
+    def build(self):
+        return self.mc_src
+
+
 def get_ref_add_pragma(mc_lines):
     # Initialize variables
     modified_lines = []
@@ -83,11 +127,8 @@ def recompile_mc(mc_path: Path, build: Path, spec_env: os._Environ):
     # Run "make"
     return make(build, spec_env)
 
-
-def perf_ref(x264_run, perf_output):
-    """Run "perf" to profile x264 reference performance."""
-    x264_cmd = [
-        x264_run / "x264_s_base.mytest-m64",
+specinvoke_args = {
+    "ref": [
         "--seek",
         "500",
         "--dumpyuv",
@@ -99,6 +140,15 @@ def perf_ref(x264_run, perf_output):
         "BuckBunny.yuv",
         "1280x720",
     ]
+}
+
+
+def perf_ref(x264_run, perf_output):
+    """Run "perf" to profile x264 reference performance."""
+    x264_cmd = [
+        x264_run / "x264_s_base.mytest-m64",
+        *specinvoke_args["ref"],
+    ]
     run(
         [
             "perf",