configure.py

"""Generate build.ninja: compile every src/*.cpp with VC6 and link into one DLL
for reccmp to diff against orig/gamemd.exe.

Uses /Z7 (debug info embedded per-object) rather than /Zi (external per-TU PDB) --
135 cl.exe invocations running in parallel under ninja would otherwise be writing
to shared PDB state, a known VC6 stability problem. /Z7 avoids any cross-process
sharing during compilation; link.exe then assembles one final PDB from the
embedded info via /DEBUG.

Flags (/O2 /Ob1) are the ones validated in tools/smoketest/GetProgress.cpp to
reproduce the original compiler's output exactly -- see docs/compiler.md.

Usage: python configure.py
Then: <ninja path from config/paths.json> -f build.ninja
"""
import json
import pathlib

REPO_ROOT = pathlib.Path(__file__).resolve().parent
SRC_DIR = REPO_ROOT / "src"
BUILD_DIR = REPO_ROOT / "build"
PATHS = json.loads((REPO_ROOT / "config" / "paths.json").read_text())

VC6_BIN = PATHS["vc6_bin"]
VC6_LIB = PATHS["vc6_lib"]
VC6_INCLUDE = PATHS["vc6_include"]
CL_EXE = f"{VC6_BIN}\\CL.EXE"
LINK_EXE = f"{VC6_BIN}\\LINK.EXE"
MSPDB_BIN = str(pathlib.Path(PATHS["vc6_bin"]).parent.parent / "Common" / "MSDev98" / "Bin")

CL_FLAGS = f'/nologo /c /O2 /Ob1 /Z7 /I"{VC6_INCLUDE}"'
LINK_FLAGS = "/nologo /DLL /DEBUG"


def main() -> None:
    cpp_files = sorted(SRC_DIR.glob("*.cpp"))
    if not cpp_files:
        print("no .cpp files in src/ -- run tools/gen_stubs.py first")
        return

    BUILD_DIR.mkdir(exist_ok=True)
    (BUILD_DIR / "obj").mkdir(exist_ok=True)

    lines = [
        f"cl = {CL_EXE}",
        f"link = {LINK_EXE}",
        f"path_prefix = {VC6_BIN};{MSPDB_BIN}",
        f"lib = {VC6_LIB}",
        "",
        "rule cl",
        "  command = cmd /c \"set PATH=$path_prefix;%PATH% && $cl " + CL_FLAGS + " /Fo$out $in\"",
        "  description = CL $in",
        "",
        "rule link",
        "  command = cmd /c \"set PATH=$path_prefix;%PATH% && $link "
        + LINK_FLAGS + " /LIBPATH:$lib /OUT:$out /PDB:$pdb $in\"",
        "  description = LINK $out",
        "",
    ]

    objs = []
    for cpp in cpp_files:
        obj = f"build/obj/{cpp.stem}.obj"
        objs.append(obj)
        lines.append(f"build {obj}: cl {cpp.relative_to(REPO_ROOT).as_posix()}")

    lines.append("")
    lines.append(
        "build build/gamemd_recomp.dll: link " + " ".join(objs)
    )
    lines.append("  pdb = build/gamemd_recomp.pdb")
    lines.append("")
    lines.append("default build/gamemd_recomp.dll")
    lines.append("")

    (REPO_ROOT / "build.ninja").write_text("\n".join(lines), encoding="utf-8")
    print(f"wrote build.ninja: {len(cpp_files)} TUs -> build/gamemd_recomp.dll")


if __name__ == "__main__":
    main()