Merge pull request #5 from nicholasjng/stable-abi-builds

Implement stable ABI builds

BUILD

@@ -1,3 +1,109 @@
+load("@bazel_skylib//lib:selects.bzl", "selects")
+load("@bazel_skylib//rules:common_settings.bzl", "bool_flag", "string_flag")
+
 licenses(["notice"])
 
 exports_files(["LICENSE"])
+
+bool_flag(
+    name = "minsize",
+    build_setting_default = False,
+)
+
+config_setting(
+    name = "with_sizeopts",
+    flag_values = {":minsize": "True"},
+)
+
+config_setting(
+    name = "without_sizeopts",
+    flag_values = {":minsize": "False"},
+)
+
+string_flag(
+    name = "py-limited-api",
+    build_setting_default = "unset",
+    values = [
+        "cp312",
+        "cp313",
+        "unset",
+    ],
+)
+
+config_setting(
+    name = "cp312",
+    flag_values = {":py-limited-api": "cp312"},
+)
+
+config_setting(
+    name = "cp313",
+    flag_values = {":py-limited-api": "cp313"},
+)
+
+config_setting(
+    name = "pyunlimitedapi",
+    flag_values = {":py-limited-api": "unset"},
+)
+
+selects.config_setting_group(
+    name = "unix",
+    match_any = [
+        "@platforms//os:linux",
+        "@platforms//os:macos",
+    ],
+)
+
+# Config setting indicating that stable ABI extension build was requested.
+selects.config_setting_group(
+    name = "stable-abi",
+    match_any = [
+        ":cp312",
+        ":cp313",
+    ],
+)
+
+# A stable ABI build on Linux or Mac.
+# This requires a different extension name (.abi3.so instead of just .so).
+selects.config_setting_group(
+    name = "stable-abi-unix",
+    match_all = [
+        ":stable-abi",
+        ":unix",
+    ],
+)
+
+# An unlimited Python ABI build on Linux or Mac. Produces a regular .so file.
+selects.config_setting_group(
+    name = "unstable-abi-unix",
+    match_all = [
+        ":pyunlimitedapi",
+        ":unix",
+    ],
+)
+
+# Is the currently configured C++ compiler not MSVC?
+selects.config_setting_group(
+    name = "nonmsvc",
+    match_any = [
+        "@rules_cc//cc/compiler:gcc",
+        "@rules_cc//cc/compiler:clang",
+        "@rules_cc//cc/compiler:clang-cl",
+        "@rules_cc//cc/compiler:mingw-gcc",
+    ],
+)
+
+selects.config_setting_group(
+    name = "msvc_and_minsize",
+    match_all = [
+        "@rules_cc//cc/compiler:msvc-cl",
+        ":with_sizeopts",
+    ],
+)
+
+selects.config_setting_group(
+    name = "nonmsvc_and_minsize",
+    match_all = [
+        ":nonmsvc",
+        ":with_sizeopts",
+    ],
+)

build_defs.bzl

@@ -11,9 +11,10 @@ which can then be included e.g. as a `data` input in a ``native.py_library``.
 """
 
 load("@bazel_skylib//rules:copy_file.bzl", "copy_file")
+load("@nanobind_bazel//:helpers.bzl", "extension_name")
 
 NANOBIND_COPTS = select({
-    Label("@nanobind//:msvc"): [],
+    Label("@rules_cc//cc/compiler:msvc-cl"): [],
     "//conditions:default": ["-fexceptions", "-fvisibility=hidden"],
 })
 
@@ -40,7 +41,6 @@ def nanobind_extension(
         features = [],
         deps = [],
         **kwargs):
-    # TODO: This might need a different suffix depending on SABI yes/no.
     native.cc_binary(
         name = name + ".so",
         srcs = srcs,
@@ -52,6 +52,12 @@ def nanobind_extension(
         **kwargs
     )
 
+    copy_file(
+        name = name + "_copy_so_to_abi3_so",
+        src = name + ".so",
+        out = name + ".abi3.so",
+    )
+
     copy_file(
         name = name + "_copy_so_to_pyd",
         src = name + ".so",
@@ -60,10 +66,7 @@ def nanobind_extension(
 
     native.alias(
         name = name,
-        actual = select({
-            "@platforms//os:windows": name + ".pyd",
-            "//conditions:default": name + ".so",
-        }),
+        actual = extension_name(name),
     )
 
 def nanobind_library(

helpers.bzl

@@ -2,7 +2,30 @@
 
 def sizeopts():
     return select({
-        "@nanobind//:msvc_and_minsize": ["/Os"],
-        "@nanobind//:nonmsvc_and_minsize": ["-Os"],
-        "@nanobind//:without_sizeopts": [],
+        "@nanobind_bazel//:msvc_and_minsize": ["/Os"],
+        "@nanobind_bazel//:nonmsvc_and_minsize": ["-Os"],
+        "@nanobind_bazel//:without_sizeopts": [],
+    })
+
+def sizedefs():
+    return select({
+        "@nanobind_bazel//:with_sizeopts": ["NB_COMPACT_ASSERTS"],
+        "@nanobind_bazel//:without_sizeopts": [],
+    })
+
+# Define the Python version hex if stable ABI builds are requested.
+def pyversionhex():
+    return select({
+        "@nanobind_bazel//:cp312": ["Py_LIMITED_API=0x030C0000"],
+        "@nanobind_bazel//:cp313": ["Py_LIMITED_API=0x030D0000"],
+        "@nanobind_bazel//:pyunlimitedapi": [],
+    })
+
+# Get the name for a built nanobind extension based on target platform
+# and stable ABI build yes/no.
+def extension_name(name):
+    return select({
+        "@platforms//os:windows": name + ".pyd",
+        "@nanobind_bazel//:stable-abi-unix": name + ".abi3.so",
+        "@nanobind_bazel//:unstable-abi-unix": name + ".so",
     })

nanobind.BUILD

@@ -5,62 +5,13 @@ Size optimizations used: -Os, LTO
 Linker optimizations used: LTCG (MSVC on Windows), linker response file (macOS only).
 """
 
-load("@bazel_skylib//lib:selects.bzl", "selects")
-load("@bazel_skylib//rules:common_settings.bzl", "bool_flag")
-load("@nanobind_bazel//:helpers.bzl", "sizeopts")
+load("@nanobind_bazel//:helpers.bzl", "pyversionhex", "sizedefs", "sizeopts")
 
 licenses(["notice"])
 
 # TODO: Change this when cleaning up exports later.
 package(default_visibility = ["//visibility:public"])
 
-bool_flag(
-    name = "minsize",
-    build_setting_default = False,
-)
-
-config_setting(
-    name = "with_sizeopts",
-    flag_values = {":minsize": "True"},
-)
-
-config_setting(
-    name = "without_sizeopts",
-    flag_values = {":minsize": "False"},
-)
-
-config_setting(
-    name = "msvc",
-    flag_values = {"@bazel_tools//tools/cpp:compiler": "msvc-cl"},
-)
-
-# Is the currently configured C++ compiler not MSVC?
-selects.config_setting_group(
-    name = "nonmsvc",
-    match_any = [
-        "@rules_cc//cc/compiler:gcc",
-        "@rules_cc//cc/compiler:clang",
-        "@rules_cc//cc/compiler:clang-cl",
-        "@rules_cc//cc/compiler:mingw-gcc",
-    ],
-)
-
-selects.config_setting_group(
-    name = "msvc_and_minsize",
-    match_all = [
-        ":msvc",
-        ":with_sizeopts",
-    ],
-)
-
-selects.config_setting_group(
-    name = "nonmsvc_and_minsize",
-    match_all = [
-        ":nonmsvc",
-        ":with_sizeopts",
-    ],
-)
-
 cc_library(
     name = "nanobind",
     srcs = glob(["src/*.cpp"]),
@@ -69,29 +20,30 @@ cc_library(
         "//conditions:default": [],
     }),
     copts = select({
-        ":msvc": [
+        "@rules_cc//cc/compiler:msvc-cl": [
             "/EHsc",  # exceptions
             "/GL",  # LTO / whole program optimization
         ],
         # clang and gcc, across all platforms.
         "//conditions:default": [
             "-fexceptions",
             "-flto",
-            "-Os",
         ],
     }) + sizeopts(),
+    defines = pyversionhex(),
     includes = [
         "ext/robin_map/include",
         "include",
     ],
     linkopts = select({
-        ":msvc": ["/LTCG"],  # MSVC.
+        "@rules_cc//cc/compiler:msvc-cl": ["/LTCG"],  # MSVC.
         "@platforms//os:macos": [
             "-Wl,@$(location :cmake/darwin-ld-cpython.sym)",  # Apple.
             "-Wl,-dead_strip",
         ],
         "//conditions:default": [],
     }),
+    local_defines = sizedefs(),  # sizeopts apply to nanobind only.
     textual_hdrs = glob(
         [
             "include/**/*.h",