1 files changed, 34 insertions, 11 deletions
diff --git a/Tools/jit/build.py b/Tools/jit/build.py
index 4d1e484b683..a0733005929 100644
--- a/Tools/jit/build.py
+++ b/Tools/jit/build.py
@@ -23,25 +23,48 @@ if __name__ == "__main__":
         "-f", "--force", action="store_true", help="force the entire JIT to be rebuilt"
     )
     parser.add_argument(
+        "-o",
+        "--output-dir",
+        help="where to output generated files",
+        required=True,
+        type=lambda p: pathlib.Path(p).resolve(),
+    )
+    parser.add_argument(
+        "-p",
+        "--pyconfig-dir",
+        help="where to find pyconfig.h",
+        required=True,
+        type=lambda p: pathlib.Path(p).resolve(),
+    )
+    parser.add_argument(
         "-v", "--verbose", action="store_true", help="echo commands as they are run"
     )
+    parser.add_argument(
+        "--cflags", help="additional flags to pass to the compiler", default=""
+    )
     args = parser.parse_args()
     for target in args.target:
         target.debug = args.debug
         target.force = args.force
         target.verbose = args.verbose
+        target.cflags = args.cflags
+        target.pyconfig_dir = args.pyconfig_dir
         target.build(
-            pathlib.Path.cwd(),
             comment=comment,
-            stencils_h=f"jit_stencils-{target.triple}.h",
             force=args.force,
+            jit_stencils=args.output_dir / f"jit_stencils-{target.triple}.h",
         )
-
-    with open("jit_stencils.h", "w") as fp:
-        for idx, target in enumerate(args.target):
-            fp.write(f"#{'if' if idx == 0 else 'elif'} {target.condition}\n")
-            fp.write(f'#include "jit_stencils-{target.triple}.h"\n')
-
-        fp.write("#else\n")
-        fp.write('#error "unexpected target"\n')
-        fp.write("#endif\n")
+    jit_stencils_h = args.output_dir / "jit_stencils.h"
+    lines = [f"// {comment}\n"]
+    guard = "#if"
+    for target in args.target:
+        lines.append(f"{guard} {target.condition}\n")
+        lines.append(f'#include "jit_stencils-{target.triple}.h"\n')
+        guard = "#elif"
+    lines.append("#else\n")
+    lines.append('#error "unexpected target"\n')
+    lines.append("#endif\n")
+    body = "".join(lines)
+    # Don't touch the file if it hasn't changed (so we don't trigger a rebuild):
+    if not jit_stencils_h.is_file() or jit_stencils_h.read_text() != body:
+        jit_stencils_h.write_text(body)