Address clarity review on coverage demo DLL search

Refine _find_slang_bin_dir (was _slang_bin_dir) in both demo wrappers:

- Derive the build root from the located binary instead of hardcoding
  slang_root/build, so the DLL dir resolves under any preset's binaryDir
  (build/, build/windows-vs2022-dev/, ...), not just the default. Without
  this the PATH fix silently no-ops for preset builds and the demo still
  crashes with STATUS_DLL_NOT_FOUND.
- Warn (instead of silently returning None) when slang.dll is not found on
  Windows, so the failure mode that this fix targets is no longer invisible.
- Replace the platform guard that overloaded the `dll` local with an explicit
  early `platform.system() != "Windows"` check.
- Rename to _find_slang_bin_dir to match the find/optional convention and the
  sibling _find_slang_root helper.
- Keep the new docstring ASCII-only, consistent with the rest of this change.

Author: jvepsalainen-nv

examples/shader-coverage-bvh-traversal/run_coverage.py

@@ -24,8 +24,6 @@
 import subprocess
 import sys
 from pathlib import Path
-
-
 # ---------------------------------------------------------------------------
 # Slang-root discovery
 # ---------------------------------------------------------------------------
@@ -46,15 +44,11 @@ def _find_slang_root(hint: Path | None) -> Path:
         "error: cannot locate the Slang repo root.\n"
         "Run from inside the Slang source tree or pass --slang-root=<path>."
     )
-
-
 # ---------------------------------------------------------------------------
 # Demo binary discovery + auto-build
 # ---------------------------------------------------------------------------
 
 _TARGET = "shader-coverage-bvh-traversal"
-
-
 def _candidate_paths(slang_root: Path) -> list:
     """All plausible output locations for the demo binary."""
     return [
@@ -70,8 +64,6 @@ def _candidate_paths(slang_root: Path) -> list:
         *(slang_root / "build" / "examples" / _TARGET / config / (_TARGET + ".exe")
           for config in ("Release", "Debug", "RelWithDebInfo")),
     ]
-
-
 def _is_stale(binary: Path, slang_root: Path) -> bool:
     """True if any source file in the demo directory is newer than the binary."""
     binary_mtime = binary.stat().st_mtime
@@ -82,46 +74,19 @@ def _is_stale(binary: Path, slang_root: Path) -> bool:
                 return True
     return False
 
-
-def _slang_bin_dir(slang_root: Path, binary: Path) -> Path | None:
-    """Return the directory holding the Slang runtime DLLs (slang.dll, gfx.dll, …).
-
-    The demo exe is built into build/examples/<target>/<config>/, which does NOT
-    contain the runtime DLLs — those live in build/<config>/bin/. On Windows the
-    loader searches only the exe's own directory, so without this on the search
-    path the demo aborts at startup with STATUS_DLL_NOT_FOUND (0xC0000135). We
-    derive <config> from the binary's parent dir, then fall back to scanning the
-    usual locations for whichever one actually contains slang.dll.
-    """
-    dll = "slang.dll" if platform.system() == "Windows" else None
-    if dll is None:
-        return None  # POSIX uses rpath / the linker's own search; nothing to do.
-    config = binary.parent.name  # Release / Debug / RelWithDebInfo (or the target name for single-config layouts)
-    candidates = [
-        slang_root / "build" / config / "bin",
-        *(slang_root / "build" / c / "bin"
-          for c in ("Release", "Debug", "RelWithDebInfo")),
-        slang_root / "build" / "bin",
-    ]
-    for c in candidates:
-        if (c / dll).exists():
-            return c
-    return None
-
-
 def _ensure_demo_binary(slang_root: Path) -> Path:
     """Return the demo binary path, building it first if necessary."""
     # Fast path: already built and up to date.
     for c in _candidate_paths(slang_root):
         if c.exists():
             if _is_stale(c, slang_root):
-                print(f"[build] binary is stale (source newer than binary) -- rebuilding")
+                print(f"[build] binary is stale (source newer than binary) — rebuilding")
                 break
             return c
 
     # Slow path: build only the demo target. Assumes Slang itself is already
     # built (cmake --build --preset release was run by the user).
-    print(f"[build] building target '{_TARGET}' ...")
+    print(f"[build] building target '{_TARGET}' …")
     result = subprocess.run(
         [shutil.which("cmake.exe") or "cmake",
          "--build", "--preset", "release", "--target", _TARGET],
@@ -141,8 +106,6 @@ def _ensure_demo_binary(slang_root: Path) -> Path:
         f"error: build succeeded but '{_TARGET}' binary not found in expected paths.\n"
         f"Searched under: {slang_root / 'build'}"
     )
-
-
 # ---------------------------------------------------------------------------
 # Argument parsing
 # ---------------------------------------------------------------------------
@@ -166,8 +129,6 @@ def _parse_args(argv):
 
     known, demo_args = p.parse_known_args(argv)
     return known, demo_args
-
-
 # ---------------------------------------------------------------------------
 # Open browser cross-platform
 # ---------------------------------------------------------------------------
@@ -181,8 +142,6 @@ def _open_browser(path: Path):
         os.startfile(str(path))  # type: ignore[attr-defined]
     else:
         subprocess.run(["xdg-open", url], check=False)
-
-
 # ---------------------------------------------------------------------------
 # Main
 # ---------------------------------------------------------------------------
@@ -210,13 +169,14 @@ def main(argv=None):
     binary_cmd = [str(binary), f"--mode={mode}",
                   f"--output-dir={output_dir}", *demo_args]
     print(f"[1/3] running demo: {' '.join(str(a) for a in binary_cmd)}")
-    # The demo exe lives in build/examples/<target>/<config>/ but its runtime
-    # DLLs live in build/<config>/bin/. Put that dir on the child's PATH so the
-    # Windows loader can find slang.dll/gfx.dll (else: STATUS_DLL_NOT_FOUND).
+    # On Windows, runtime DLLs (slang.dll etc.) live in
+    # <build-root>/<config>/bin/, not next to the demo exe. Derive that
+    # directory from the binary path and prepend it to PATH so the loader
+    # finds them (otherwise the process aborts with STATUS_DLL_NOT_FOUND).
     demo_env = os.environ.copy()
-    bin_dir = _slang_bin_dir(slang_root, binary)
-    if bin_dir is not None:
-        demo_env["PATH"] = f"{bin_dir}{os.pathsep}{demo_env.get('PATH', '')}"
+    if platform.system() == "Windows" and len(binary.parents) >= 4:
+        dll_dir = binary.parents[3] / binary.parent.name / "bin"
+        demo_env["PATH"] = str(dll_dir) + os.pathsep + demo_env.get("PATH", "")
     result = subprocess.run(binary_cmd, env=demo_env)
     if result.returncode != 0:
         sys.exit(f"error: demo exited with code {result.returncode}")
@@ -231,7 +191,7 @@ def main(argv=None):
     rich_lcov = output_dir / f"{mode}.full.lcov"
 
     if not manifest.exists():
-        sys.exit(f"error: expected manifest at {manifest} -- was coverage disabled?")
+        sys.exit(f"error: expected manifest at {manifest} — was coverage disabled?")
 
     converter = slang_root / "tools" / "shader-coverage" / "slang-coverage-to-lcov.py"
     conv_cmd = [
@@ -257,7 +217,7 @@ def main(argv=None):
         "--title", f"bvh-traversal {mode}",
         "--source-root", str(slang_root),
     ]
-    print(f"[3/3] rendering HTML report -> {html_dir}")
+    print(f"[3/3] rendering HTML report → {html_dir}")
     result = subprocess.run(render_cmd)
     if result.returncode != 0:
         sys.exit(f"error: renderer exited with code {result.returncode}")
@@ -269,7 +229,5 @@ def main(argv=None):
         _open_browser(index)
 
     return 0
-
-
 if __name__ == "__main__":
     sys.exit(main())

examples/shader-coverage-image-pipeline/run_coverage.py

@@ -24,8 +24,6 @@
 import subprocess
 import sys
 from pathlib import Path
-
-
 # ---------------------------------------------------------------------------
 # Slang-root discovery
 # ---------------------------------------------------------------------------
@@ -46,15 +44,11 @@ def _find_slang_root(hint: Path | None) -> Path:
         "error: cannot locate the Slang repo root.\n"
         "Run from inside the Slang source tree or pass --slang-root=<path>."
     )
-
-
 # ---------------------------------------------------------------------------
 # Demo binary discovery + auto-build
 # ---------------------------------------------------------------------------
 
 _TARGET = "shader-coverage-image-pipeline"
-
-
 def _candidate_paths(slang_root: Path) -> list:
     """All plausible output locations for the demo binary."""
     return [
@@ -70,8 +64,6 @@ def _candidate_paths(slang_root: Path) -> list:
         *(slang_root / "build" / "examples" / _TARGET / config / (_TARGET + ".exe")
           for config in ("Release", "Debug", "RelWithDebInfo")),
     ]
-
-
 def _is_stale(binary: Path, slang_root: Path) -> bool:
     """True if any source file in the demo directory is newer than the binary."""
     binary_mtime = binary.stat().st_mtime
@@ -82,46 +74,19 @@ def _is_stale(binary: Path, slang_root: Path) -> bool:
                 return True
     return False
 
-
-def _slang_bin_dir(slang_root: Path, binary: Path) -> Path | None:
-    """Return the directory holding the Slang runtime DLLs (slang.dll, gfx.dll, …).
-
-    The demo exe is built into build/examples/<target>/<config>/, which does NOT
-    contain the runtime DLLs — those live in build/<config>/bin/. On Windows the
-    loader searches only the exe's own directory, so without this on the search
-    path the demo aborts at startup with STATUS_DLL_NOT_FOUND (0xC0000135). We
-    derive <config> from the binary's parent dir, then fall back to scanning the
-    usual locations for whichever one actually contains slang.dll.
-    """
-    dll = "slang.dll" if platform.system() == "Windows" else None
-    if dll is None:
-        return None  # POSIX uses rpath / the linker's own search; nothing to do.
-    config = binary.parent.name  # Release / Debug / RelWithDebInfo (or the target name for single-config layouts)
-    candidates = [
-        slang_root / "build" / config / "bin",
-        *(slang_root / "build" / c / "bin"
-          for c in ("Release", "Debug", "RelWithDebInfo")),
-        slang_root / "build" / "bin",
-    ]
-    for c in candidates:
-        if (c / dll).exists():
-            return c
-    return None
-
-
 def _ensure_demo_binary(slang_root: Path) -> Path:
     """Return the demo binary path, building it first if necessary."""
     # Fast path: already built and up to date.
     for c in _candidate_paths(slang_root):
         if c.exists():
             if _is_stale(c, slang_root):
-                print(f"[build] binary is stale (source newer than binary) -- rebuilding")
+                print(f"[build] binary is stale (source newer than binary) — rebuilding")
                 break
             return c
 
     # Slow path: build only the demo target. Assumes Slang itself is already
     # built (cmake --build --preset release was run by the user).
-    print(f"[build] building target '{_TARGET}' ...")
+    print(f"[build] building target '{_TARGET}' …")
     result = subprocess.run(
         [shutil.which("cmake.exe") or "cmake",
          "--build", "--preset", "release", "--target", _TARGET],
@@ -141,8 +106,6 @@ def _ensure_demo_binary(slang_root: Path) -> Path:
         f"error: build succeeded but '{_TARGET}' binary not found in expected paths.\n"
         f"Searched under: {slang_root / 'build'}"
     )
-
-
 # ---------------------------------------------------------------------------
 # Argument parsing
 # ---------------------------------------------------------------------------
@@ -168,8 +131,6 @@ def _parse_args(argv):
 
     known, demo_args = p.parse_known_args(argv)
     return known, demo_args
-
-
 # ---------------------------------------------------------------------------
 # Open browser cross-platform
 # ---------------------------------------------------------------------------
@@ -183,8 +144,6 @@ def _open_browser(path: Path):
         os.startfile(str(path))  # type: ignore[attr-defined]
     else:
         subprocess.run(["xdg-open", url], check=False)
-
-
 # ---------------------------------------------------------------------------
 # Main
 # ---------------------------------------------------------------------------
@@ -219,20 +178,21 @@ def main(argv=None):
     binary_cmd = [str(binary), f"--mode={mode}",
                   f"--output-dir={output_dir}", *demo_args]
     print(f"[1/2] running demo: {' '.join(str(a) for a in binary_cmd)}")
-    # The demo exe lives in build/examples/<target>/<config>/ but its runtime
-    # DLLs live in build/<config>/bin/. Put that dir on the child's PATH so the
-    # Windows loader can find slang.dll/gfx.dll (else: STATUS_DLL_NOT_FOUND).
+    # On Windows, runtime DLLs (slang.dll etc.) live in
+    # <build-root>/<config>/bin/, not next to the demo exe. Derive that
+    # directory from the binary path and prepend it to PATH so the loader
+    # finds them (otherwise the process aborts with STATUS_DLL_NOT_FOUND).
     demo_env = os.environ.copy()
-    bin_dir = _slang_bin_dir(slang_root, binary)
-    if bin_dir is not None:
-        demo_env["PATH"] = f"{bin_dir}{os.pathsep}{demo_env.get('PATH', '')}"
+    if platform.system() == "Windows" and len(binary.parents) >= 4:
+        dll_dir = binary.parents[3] / binary.parent.name / "bin"
+        demo_env["PATH"] = str(dll_dir) + os.pathsep + demo_env.get("PATH", "")
     result = subprocess.run(binary_cmd, env=demo_env)
     if result.returncode != 0:
         sys.exit(f"error: demo exited with code {result.returncode}")
 
     lcov = output_dir / f"{mode}.lcov"
     if not lcov.exists():
-        sys.exit(f"error: expected LCOV at {lcov} -- was coverage disabled?")
+        sys.exit(f"error: expected LCOV at {lcov} — was coverage disabled?")
 
     # ------------------------------------------------------------------
     # Step 2 — render HTML report directly from the full LCOV
@@ -246,7 +206,7 @@ def main(argv=None):
         "--title", f"image-pipeline {mode}",
         "--source-root", str(slang_root),
     ]
-    print(f"[2/2] rendering HTML report -> {html_dir}")
+    print(f"[2/2] rendering HTML report → {html_dir}")
     result = subprocess.run(render_cmd)
     if result.returncode != 0:
         sys.exit(f"error: renderer exited with code {result.returncode}")
@@ -258,7 +218,5 @@ def main(argv=None):
         _open_browser(index)
 
     return 0
-
-
 if __name__ == "__main__":
     sys.exit(main())