build: unify compiler flags

cuda_bindings/build_hooks.py

@@ -437,21 +437,28 @@ def _resolve_toolchain(debug=False, compile_for_coverage=False):
     extra_link_args = []
 
     if name == "msvc":
+        # c++14: raising to c++17 costs a measured ~15% on launch_{256,512}_args
+        # from gcc's c++17 variadic-template expansion.
+        extra_compile_args += ["/std:c++14", "/O2"]
         if debug:
             raise RuntimeError("Debuggable builds are not supported on Windows.")
     else:
         # Common Linux compile flags.
-        extra_compile_args += ["-std=c++14", "-Wno-deprecated-declarations"]
+        # c++14: raising to c++17 costs a measured ~15% on launch_{256,512}_args
+        # from gcc's c++17 variadic-template expansion.
+        extra_compile_args += ["-std=c++14"]
+        # cudaMemcpy*Array* and cudaGetDriverEntryPoint are deprecated but still
+        # supported; suppress the resulting warnings so a future -Werror build
+        # is not broken by Cython-generated calls we cannot control.
+        extra_compile_args += ["-Wno-deprecated-declarations"]
         # Compiler-specific flags.
-        if name == "gnu":
-            extra_compile_args += ["-fpermissive", "-fno-var-tracking-assignments"]
-        elif name == "llvm":
+        if name == "llvm":
             extra_link_args += ["-fuse-ld=lld"]
         # Common Linux debug/opt flags.
         if debug:
             extra_compile_args += ["-g", "-O0", "-D _GLIBCXX_ASSERTIONS"]
         else:
-            extra_compile_args += ["-g0", "-O3"]
+            extra_compile_args += ["-g0", "-O2"]
             extra_link_args += ["-Wl,--strip-all"]
 
     if compile_for_coverage:

cuda_bindings/tests/cython/build_tests.py

@@ -8,19 +8,39 @@
 so `cimport cuda.bindings.*` fails to locate the .pxd files. We resolve
 the namespace package's source root from `cuda.bindings.__file__` and pass
 it via `include_path=` so cythonize finds the .pxd tree on every platform.
+
+When CUDA_PYTHON_CYTHON_CACHE_DIR is set, cythonize uses the same cache
+namespacing and include-path aliasing as cuda_bindings/build_hooks.py.
 """
 
 from __future__ import annotations
 
+import importlib.util
 import os
 import sys
 from pathlib import Path
 
+import Cython
 from Cython.Build import cythonize
 from setuptools import setup
 
 import cuda.bindings
 
+_COMPILER_DIRECTIVES = {"freethreading_compatible": True}
+
+
+def _load_build_hooks():
+    # PEP 517 backend, not an installed module. Load by path so we do not put
+    # cuda_bindings/ on sys.path (that would shadow the installed package).
+    build_hooks_path = Path(__file__).resolve().parents[2] / "build_hooks.py"
+    spec = importlib.util.spec_from_file_location("cuda_bindings_build_hooks", build_hooks_path)
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+build_hooks = _load_build_hooks()
+
 
 def _bindings_source_root() -> Path:
     # cuda.bindings.__file__ -> .../<root>/cuda/bindings/__init__.py
@@ -32,6 +52,41 @@ def _bindings_source_root() -> Path:
     return root
 
 
+def _cythonize_tests(pyx_files):
+    cache_path = build_hooks._cython_cache_path(
+        "cuda-bindings-cython-tests",
+        compiler_directives=_COMPILER_DIRECTIVES,
+        language_level=3,
+        cplus=True,
+    )
+    cythonize_kwargs = {
+        "language_level": 3,
+        "nthreads": 1,
+        "compiler_directives": _COMPILER_DIRECTIVES,
+        "cache": cache_path,
+    }
+    if cache_path is None:
+        return cythonize(
+            pyx_files,
+            include_path=[str(_bindings_source_root())],
+            **cythonize_kwargs,
+        )
+
+    # Distinct alias names so a concurrent package build's .cython-stdlib /
+    # .cython-bindings symlinks are not replaced. Relative aliases resolve
+    # next to build_hooks.py (package root).
+    stdlib_target = Path(Cython.__file__).parent / "Includes"
+    with (
+        build_hooks._stable_cython_alias(stdlib_target, Path(".cython-stdlib-tests")) as rel_stdlib,
+        build_hooks._stable_cython_alias(_bindings_source_root(), Path(".cython-bindings-tests")) as rel_bindings,
+    ):
+        return cythonize(
+            pyx_files,
+            include_path=[".", rel_bindings, rel_stdlib],
+            **cythonize_kwargs,
+        )
+
+
 def main() -> None:
     script_dir = Path(__file__).resolve().parent
     # Avoid appending the absolute checkout path under build/temp: the
@@ -41,13 +96,7 @@ def main() -> None:
     if not pyx_files:
         raise SystemExit(f"no test_*.pyx files under {script_dir}")
 
-    ext_modules = cythonize(
-        pyx_files,
-        language_level=3,
-        nthreads=1,
-        include_path=[str(_bindings_source_root())],
-        compiler_directives={"freethreading_compatible": True},
-    )
+    ext_modules = _cythonize_tests(pyx_files)
 
     # pytest imports each extension by bare module name (see test_cython.py),
     # so build in-place next to its .pyx regardless of the invoking cwd.

cuda_bindings/tests/test_build_hooks.py

@@ -148,9 +148,8 @@ def test_gnu_sets_env_and_flags(self, monkeypatch):
         assert os.environ["CXX"] == "g++"
         assert os.environ["LDCXXSHARED"] == "g++ -shared -Wl,-O1"
         assert "LDSHARED" not in os.environ
-        # gcc-only flags are present (this is the point of P2: explicit gnu must use gcc, not generic cc)
-        assert "-fpermissive" in cargs
-        assert "-fno-var-tracking-assignments" in cargs
+        assert "-fpermissive" not in cargs
+        assert "-fno-var-tracking-assignments" not in cargs
 
     @pytest.mark.agent_authored(model="grok-4.6")
     def test_llvm_keeps_sccache_prefix(self, monkeypatch):
@@ -167,14 +166,31 @@ def test_llvm_keeps_sccache_prefix(self, monkeypatch):
         # The launcher prefixes CC/CXX only; the shared linker command is the bare compiler.
         assert os.environ["LDCXXSHARED"] == "clang++ -shared -Wl,-O1"
 
-    @pytest.mark.agent_authored(model="glm-5.2")
-    def test_gnu_keeps_gcc_only_flags(self, monkeypatch):
+    @pytest.mark.agent_authored(model="claude-sonnet-4-6")
+    def test_linux_opt_flag_set(self, monkeypatch):
+        """Linux opt build: -std=c++14, -O2, -Wno-deprecated-declarations; no -O3 or gnu-only flags."""
         if sys.platform == "win32":
-            pytest.skip("gnu only valid on Linux")
-        monkeypatch.setenv("CUDA_PYTHON_TOOLCHAIN", "gnu")
-        _name, _cc, _cxx, cargs, _largs = build_hooks._resolve_toolchain()
-        assert "-fpermissive" in cargs
-        assert "-fno-var-tracking-assignments" in cargs
+            pytest.skip("Linux flags only")
+        monkeypatch.delenv("CUDA_PYTHON_TOOLCHAIN", raising=False)
+        _name, _cc, _cxx, cargs, largs = build_hooks._resolve_toolchain(debug=False)
+        assert "-std=c++14" in cargs
+        assert "-Wno-deprecated-declarations" in cargs
+        assert "-g0" in cargs
+        assert "-O2" in cargs
+        assert "-O3" not in cargs
+        assert "-fpermissive" not in cargs
+        assert "-fno-var-tracking-assignments" not in cargs
+        assert "-Wl,--strip-all" in largs
+
+    @pytest.mark.agent_authored(model="claude-sonnet-4-6")
+    def test_msvc_opt_flag_set(self, monkeypatch):
+        """MSVC opt build emits /std:c++14 and /O2."""
+        if sys.platform != "win32":
+            pytest.skip("MSVC flags only on Windows")
+        monkeypatch.delenv("CUDA_PYTHON_TOOLCHAIN", raising=False)
+        _name, _cc, _cxx, cargs, _largs = build_hooks._resolve_toolchain(debug=False)
+        assert "/std:c++14" in cargs
+        assert "/O2" in cargs
 
     @pytest.mark.agent_authored(model="claude-sonnet-5.5")
     def test_explicit_toolchain_prefers_env_ldcxxshared(self, monkeypatch):

cuda_core/build_hooks.py

@@ -484,11 +484,13 @@ def _resolve_toolchain(debug=False, compile_for_coverage=False):
     extra_link_args = []
 
     if name == "msvc":
-        extra_compile_args += ["/std:c++17"]
+        # c++17: required by structured bindings and if constexpr in cuda/core/_cpp/.
+        extra_compile_args += ["/std:c++17", "/O2"]
         if debug:
             raise RuntimeError("Debuggable builds are not supported on Windows.")
     else:
         # Common Linux compile flags.
+        # c++17: required by structured bindings and if constexpr in cuda/core/_cpp/.
         extra_compile_args += ["-std=c++17"]
         # Compiler-specific flags.
         if name == "llvm":

cuda_core/tests/cython/build_tests.py

@@ -8,19 +8,39 @@
 so `cimport cuda.bindings.*` fails to locate the .pxd files. We resolve
 the namespace package's source root from `cuda.bindings.__file__` and pass
 it via `include_path=` so cythonize finds the .pxd tree on every platform.
+
+When CUDA_PYTHON_CYTHON_CACHE_DIR is set, cythonize uses the same cache
+namespacing and include-path aliasing as cuda_core/build_hooks.py.
 """
 
 from __future__ import annotations
 
+import importlib.util
 import os
 import sys
 from pathlib import Path
 
+import Cython
 from Cython.Build import cythonize
 from setuptools import setup
 
 import cuda.bindings
 
+_COMPILER_DIRECTIVES = {"freethreading_compatible": True}
+
+
+def _load_build_hooks():
+    # PEP 517 backend, not an installed module. Load by path so we do not put
+    # cuda_core/ on sys.path (that would shadow the installed package).
+    build_hooks_path = Path(__file__).resolve().parents[2] / "build_hooks.py"
+    spec = importlib.util.spec_from_file_location("cuda_core_build_hooks", build_hooks_path)
+    module = importlib.util.module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+build_hooks = _load_build_hooks()
+
 
 def _bindings_source_root() -> Path:
     # cuda.bindings.__file__ -> .../<root>/cuda/bindings/__init__.py
@@ -32,26 +52,55 @@ def _bindings_source_root() -> Path:
     return root
 
 
+def _cythonize_tests(pyx_files):
+    cache_path = build_hooks._cython_cache_path(
+        "cuda-core-cython-tests",
+        compiler_directives=_COMPILER_DIRECTIVES,
+        language_level=3,
+        cplus=True,
+    )
+    cythonize_kwargs = {
+        "language_level": 3,
+        "compiler_directives": _COMPILER_DIRECTIVES,
+        "cache": cache_path,
+    }
+    if cache_path is None:
+        return cythonize(
+            pyx_files,
+            include_path=[str(_bindings_source_root())],
+            **cythonize_kwargs,
+        )
+
+    # Distinct alias names so a concurrent package build's .cython-stdlib /
+    # .cython-bindings symlinks are not replaced. Relative aliases resolve
+    # next to build_hooks.py (package root).
+    stdlib_target = Path(Cython.__file__).parent / "Includes"
+    with (
+        build_hooks._stable_cython_alias(stdlib_target, Path(".cython-stdlib-tests")) as rel_stdlib,
+        build_hooks._stable_cython_alias(_bindings_source_root(), Path(".cython-bindings-tests")) as rel_bindings,
+    ):
+        return cythonize(
+            pyx_files,
+            include_path=[".", rel_bindings, rel_stdlib],
+            **cythonize_kwargs,
+        )
+
+
 def main() -> None:
     script_dir = Path(__file__).resolve().parent
-    pyx_files = sorted(str(p) for p in script_dir.glob("test_*.pyx"))
+    pyx_files = sorted(p.name for p in script_dir.glob("test_*.pyx"))
     if not pyx_files:
         raise SystemExit(f"no test_*.pyx files under {script_dir}")
 
-    ext_modules = cythonize(
-        pyx_files,
-        language_level=3,
-        include_path=[str(_bindings_source_root())],
-        compiler_directives={"freethreading_compatible": True},
-    )
-
     # `build_ext --inplace` places the compiled .so relative to the current
     # working directory, but pixi runs this task from the project root. pytest
     # imports each extension by bare module name (see test_cython.py), which
     # only resolves when the .so sits in tests/cython (the dir pytest puts on
-    # sys.path). chdir here so the .so lands next to its .pyx regardless of the
-    # invoking cwd.
+    # sys.path). chdir before cythonize so alias relpaths and the .so location
+    # are stable regardless of the invoking cwd.
     os.chdir(script_dir)
+    ext_modules = _cythonize_tests(pyx_files)
+
     sys.argv = [sys.argv[0], "build_ext", "--inplace"]
     setup(name="cuda_core_cython_tests", ext_modules=ext_modules)
 

cuda_core/tests/test_build_hooks.py

@@ -976,8 +976,8 @@ def test_gnu_sets_env_and_flags(self, monkeypatch):
         assert os.environ["CXX"] == "g++"
         assert os.environ["LDCXXSHARED"] == "g++ -shared -Wl,-O1"
         assert "LDSHARED" not in os.environ
-        # gcc-only flags are present (this is the point of P2: explicit gnu must use gcc, not generic cc)
-        assert "-fpermissive" not in cargs  # cuda.core gnu flags don't include it; bindings do
+        # Neither cuda.core nor cuda.bindings sets these gcc-only flags.
+        assert "-fpermissive" not in cargs
         assert "-fno-var-tracking-assignments" not in cargs
 
     @pytest.mark.agent_authored(model="grok-4.6")
@@ -1018,6 +1018,30 @@ def test_explicit_toolchain_falls_back_to_ldshared_then_shared_flag(self, monkey
         build_hooks._resolve_toolchain()
         assert os.environ["LDCXXSHARED"] == "clang++ -shared"
 
+    @pytest.mark.agent_authored(model="claude-sonnet-4-6")
+    def test_linux_opt_flag_set(self, monkeypatch):
+        """Linux opt build: -std=c++17, -O2; no gnu-only flags."""
+        if sys.platform == "win32":
+            pytest.skip("Linux flags only")
+        monkeypatch.delenv("CUDA_PYTHON_TOOLCHAIN", raising=False)
+        _name, _cc, _cxx, cargs, largs = build_hooks._resolve_toolchain(debug=False)
+        assert "-std=c++17" in cargs
+        assert "-g0" in cargs
+        assert "-O2" in cargs
+        assert "-fpermissive" not in cargs
+        assert "-fno-var-tracking-assignments" not in cargs
+        assert "-Wl,--strip-all" in largs
+
+    @pytest.mark.agent_authored(model="claude-sonnet-4-6")
+    def test_msvc_opt_flag_set(self, monkeypatch):
+        """MSVC opt build emits /std:c++17 and /O2."""
+        if sys.platform != "win32":
+            pytest.skip("MSVC flags only on Windows")
+        monkeypatch.delenv("CUDA_PYTHON_TOOLCHAIN", raising=False)
+        _name, _cc, _cxx, cargs, _largs = build_hooks._resolve_toolchain(debug=False)
+        assert "/std:c++17" in cargs
+        assert "/O2" in cargs
+
 
 class TestWithSccache:
     """_with_sccache: keep a leading sccache token, swap the compiler."""