Feature: Add support for specifying a cstdlib other than glibc. (#7)

* feat: Add support for specifying different cstdlib

We'd like to be able to specify either glibc or musl. This adds an extra
layer of heirarchy that allows a user to specify not only the
architecture and buildroot version but also the cstdlib.

* chore: Update toolchains w/ cstdlib support

Runs the update script and adds a single example of a musl target for
aarch64.

README.md

@@ -34,12 +34,14 @@ load("@bazel_bootlin//toolchains:toolchains.bzl", "bootlin_toolchain_deps")
 
 bootlin_toolchain_deps(
     architecture = "x86-64-core-i7",
+    cstdlib = "glibc",
     buildroot_version = "2020.08-1",
 )
 ```
 
 * `architecture` - refers to the [architecture
   string](https://toolchains.bootlin.com/toolchains.html) used by Bootlin.
+* `cstdlib` - refers to the [cstdlib string](https://toolchains.bootlin.com/releases_x86-64-core-i7.html#:~:text=64%2Dcore%2Di7%2D%2D-,glibc%2D%2Dstable,-%2D2022.08%2D1%20Download) used by bootlin.
 * `buildroot_version` - refers to the [Buildroot version
   string](https://toolchains.bootlin.com/releases_x86-64-core-i7.html#:~:text=i7%2D%2Dglibc%2D%2Dstable%2D-,2021.11%2D1,-Download%20sha256)
 used by Bootlin.
@@ -49,12 +51,12 @@ used by Bootlin.
 Currently `bazel_bootlin` only provides the "glibc--stable" version of the following Bootlin
 toolchains:
 
-| Architecture | Buildroot Version |
-| --- | --- |
-| `x86-64` | `2022.08-1`, `2021.11-5` |
-| `x86-64-core-i7` | `2020.08-1` |
-| `aarch64` | `2021.11-1`, `2020.08-1` |
-| `armv7-eabihf` | `2020.08-1` |
+| Architecture | cstdlib | Buildroot Version |
+| --- | --- | --- |
+| `x86-64` | `glibc` | `2022.08-1`, `2021.11-5` |
+| `x86-64-core-i7` |`glibc` | `2020.08-1` |
+| `aarch64` | `glibc`, `musl` | `2021.11-1`, `2020.08-1` |
+| `armv7-eabihf` | `glibc` | `2020.08-1` |
 
 This list is easily expanded.  If a toolchain of interest isn't available feel free to submit and
 [issue](https://github.com/agoessling/bazel_bootlin/issues), or alternatively take a look at
@@ -74,7 +76,7 @@ toolchain that is included.  The platforms specify `constraint_value` for the ca
 
 ```Starlark
 platform(
-    name = "{architecture}-linux-gnu-{buildroot_version}",
+    name = "{architecture}-linux-{cstdlib}-{buildroot_version}",
     constraint_values = [
         "@platforms//cpu:{architecture}",
         "@platforms//os:linux",
@@ -91,15 +93,15 @@ In order to enable toolchain selection via platforms, Bazel requires a special f
 target platform:
 
 ```Shell
-bazel build --incompatible_enable_cc_toolchain_resolution --platforms=@bazel_bootlin//platforms:{architecture}-linux-gnu-{buildroot_version} //...
+bazel build --incompatible_enable_cc_toolchain_resolution --platforms=@bazel_bootlin//platforms:{architecture}-linux-{cstdlib}-{buildroot_version} //...
 ```
 
 The ergonomics can be improved by placing the flags in a
 [`.bazelrc`](https://bazel.build/docs/bazelrc) file:
 
 ```Shell
 build --incompatible_enable_cc_toolchain_resolution
-build --platforms=@bazel_bootlin//platforms:{architecture}-linux-gnu-{buildroot_version}
+build --platforms=@bazel_bootlin//platforms:{architecture}-linux-{cstdlib}-{buildroot_version}
 ```
 
 Then a simple `bazel build //...` will utilize the desired toolchain.

platforms/platforms.bzl

@@ -2,22 +2,23 @@ load("@bazel_bootlin//toolchains:toolchain_info.bzl", "AVAILABLE_TOOLCHAINS")
 
 def all_platforms():
     for architecture in AVAILABLE_TOOLCHAINS:
-        for buildroot_version in AVAILABLE_TOOLCHAINS[architecture]:
-            if buildroot_version not in native.existing_rules():
-                native.constraint_value(
-                    name = buildroot_version,
-                    constraint_setting = "@bazel_bootlin//platforms:buildroot_version",
+        for cstdlib  in AVAILABLE_TOOLCHAINS[architecture]:
+            for buildroot_version in AVAILABLE_TOOLCHAINS[architecture][cstdlib]:
+                if buildroot_version not in native.existing_rules():
+                    native.constraint_value(
+                        name = buildroot_version,
+                        constraint_setting = "@bazel_bootlin//platforms:buildroot_version",
+                        visibility = ["//visibility:public"],
+                    )
+
+                native.platform(
+                    name = "{0}-linux-{1}-{2}".format(architecture, cstdlib, buildroot_version),
+                    constraint_values = [
+                        "@platforms//cpu:{0}".format(
+                            AVAILABLE_TOOLCHAINS[architecture][cstdlib][buildroot_version]["platform_arch"],
+                        ),
+                        "@platforms//os:linux",
+                        "@bazel_bootlin//platforms:{0}".format(buildroot_version),
+                    ],
                     visibility = ["//visibility:public"],
                 )
-
-            native.platform(
-                name = "{0}-linux-gnu-{1}".format(architecture, buildroot_version),
-                constraint_values = [
-                    "@platforms//cpu:{0}".format(
-                        AVAILABLE_TOOLCHAINS[architecture][buildroot_version]["platform_arch"],
-                    ),
-                    "@platforms//os:linux",
-                    "@bazel_bootlin//platforms:{0}".format(buildroot_version),
-                ],
-                visibility = ["//visibility:public"],
-            )

setup_toolchains.py

@@ -3,41 +3,56 @@
 
 _AVAILABLE_TOOLCHAINS = {
     'x86-64': {
-        '2021.11-5': {
-            'sha256': '6fe812add925493ea0841365f1fb7ca17fd9224bab61a731063f7f12f3a621b0',
-            'platform_arch': 'x86_64',
-            'tool_prefix': 'x86_64-buildroot-linux-gnu',
-        },
-        '2022.08-1': {
-            'sha256': '861c1e8ad0a66e4c28e7a1f8319d68080ab0ff8d16a765e65540f1957203a190',
-            'platform_arch': 'x86_64',
-            'tool_prefix': 'x86_64-buildroot-linux-gnu',
+        'glibc': {
+          '2021.11-5': {
+              'sha256': '6fe812add925493ea0841365f1fb7ca17fd9224bab61a731063f7f12f3a621b0',
+              'platform_arch': 'x86_64',
+              'tool_prefix': 'x86_64-buildroot-linux-gnu',
+          },
+          '2022.08-1': {
+              'sha256': '861c1e8ad0a66e4c28e7a1f8319d68080ab0ff8d16a765e65540f1957203a190',
+              'platform_arch': 'x86_64',
+              'tool_prefix': 'x86_64-buildroot-linux-gnu',
+          },
         },
     },
     'x86-64-core-i7': {
-        '2020.08-1': {
-            'sha256': '3dd408e857f5c8e579748995477f2783fcf5ad0aac89719ea3c5c75446dfa63c',
-            'platform_arch': 'x86_64',
-            'tool_prefix': 'x86_64-buildroot-linux-gnu',
+        'glibc': {
+          '2020.08-1': {
+              'sha256': '3dd408e857f5c8e579748995477f2783fcf5ad0aac89719ea3c5c75446dfa63c',
+              'platform_arch': 'x86_64',
+              'tool_prefix': 'x86_64-buildroot-linux-gnu',
+          },
         },
     },
     'aarch64': {
-        '2021.11-1': {
-            'sha256': 'dec070196608124fa14c3f192364c5b5b057d7f34651ad58ebb8fc87959c97f7',
-            'platform_arch': 'aarch64',
-            'tool_prefix': 'aarch64-buildroot-linux-gnu',
+        'glibc': {
+          '2021.11-1': {
+              'sha256': 'dec070196608124fa14c3f192364c5b5b057d7f34651ad58ebb8fc87959c97f7',
+              'platform_arch': 'aarch64',
+              'tool_prefix': 'aarch64-buildroot-linux-gnu',
+          },
+          '2020.08-1': {
+              'sha256': '8ab7a2f17cb96621b048ab0a872650dd62faa54cd74c961b9902b8c04bff7dd1',
+              'platform_arch': 'aarch64',
+              'tool_prefix': 'aarch64-buildroot-linux-gnu',
+          },
         },
-        '2020.08-1': {
-            'sha256': '8ab7a2f17cb96621b048ab0a872650dd62faa54cd74c961b9902b8c04bff7dd1',
-            'platform_arch': 'aarch64',
-            'tool_prefix': 'aarch64-buildroot-linux-gnu',
+        'musl': {
+            '2021.11-1': {
+                'sha256': '6919b4cf04b8c5628a2a93bcf4b05e1143ab15dfb4bc2acde02a2e3c075bf041',
+                'platform_arch': 'aarch64',
+                'tool_prefix': 'aarch64-buildroot-linux-musl',
+            },
         },
     },
     'armv7-eabihf': {
-        '2020.08-1': {
-            'sha256': '7b6682603af9a9b5c0e46fd57165723483bb68295e827d14d238e63f33a147a8',
-            'platform_arch': 'armv7',
-            'tool_prefix': 'arm-buildroot-linux-gnueabihf',
+        'glibc': {
+          '2020.08-1': {
+              'sha256': '7b6682603af9a9b5c0e46fd57165723483bb68295e827d14d238e63f33a147a8',
+              'platform_arch': 'armv7',
+              'tool_prefix': 'arm-buildroot-linux-gnueabihf',
+          },
         },
     },
 }
@@ -71,31 +86,37 @@
 
 
 def create_wrappers(wrapper_dir):
-  for arch, buildroot_versions in _AVAILABLE_TOOLCHAINS.items():
+  for arch, cstdlibs in _AVAILABLE_TOOLCHAINS.items():
     try:
       os.mkdir(os.path.join(wrapper_dir, arch))
     except FileExistsError:
       pass
 
-    for version, version_info in buildroot_versions.items():
+    for cstdlib, buildroot_versions in cstdlibs.items():
       try:
-        os.mkdir(os.path.join(wrapper_dir, arch, version))
+        os.mkdir(os.path.join(wrapper_dir, arch, cstdlib))
       except FileExistsError:
         pass
 
-      for tool, tool_info in _ALL_TOOLS.items():
-        toolchain_name = f'{arch}-linux-gnu-{version}'
-        wrapper_name = f'{toolchain_name}-{tool}'
-        actual_tool_name = f'{version_info["tool_prefix"]}-{tool_info["buildroot_name"]}'
-        wrapper_path = os.path.join(wrapper_dir, arch, version, wrapper_name)
+      for version, version_info in buildroot_versions.items():
+        try:
+          os.mkdir(os.path.join(wrapper_dir, arch, cstdlib, version))
+        except FileExistsError:
+          pass
+
+        for tool, tool_info in _ALL_TOOLS.items():
+          toolchain_name = f'{arch}-linux-{cstdlib}-{version}'
+          wrapper_name = f'{toolchain_name}-{tool}'
+          actual_tool_name = f'{version_info["tool_prefix"]}-{tool_info["buildroot_name"]}'
+          wrapper_path = os.path.join(wrapper_dir, arch, cstdlib, version, wrapper_name)
 
-        with open(wrapper_path, 'w') as f:
-          f.write('#!/bin/bash\n')
-          # Uses buildroot's ".br_real" wrapper to allow -no-canonical-prefix,
-          # -fno-canonical-system-headers, and --sysroot to correctly work (using relative paths).
-          f.write(f'exec external/{toolchain_name}/bin/{actual_tool_name} $@\n')
+          with open(wrapper_path, 'w') as f:
+            f.write('#!/bin/bash\n')
+            # Uses buildroot's ".br_real" wrapper to allow -no-canonical-prefix,
+            # -fno-canonical-system-headers, and --sysroot to correctly work (using relative paths).
+            f.write(f'exec external/{toolchain_name}/bin/{actual_tool_name} $@\n')
 
-        os.chmod(wrapper_path, 0o777)
+          os.chmod(wrapper_path, 0o777)
 
 
 def write_toolchain_info(filename):
@@ -110,11 +131,12 @@ def write_test_script(filename):
     f.write('set -e\n')
     f.write('set -o xtrace\n\n')
 
-    for arch, buildroot_versions in _AVAILABLE_TOOLCHAINS.items():
-      for version in buildroot_versions:
-        platform = f'@bazel_bootlin//platforms:{arch}-linux-gnu-{version}'
-        f.write(f'bazel build --verbose_failures --platforms={platform} //test:test_cpp\n')
-        f.write(f'bazel build --verbose_failures --platforms={platform} //test:test_c\n')
+    for arch, cstdlibs in _AVAILABLE_TOOLCHAINS.items():
+      for cstdlib, buildroot_versions in cstdlibs.items():
+        for version in buildroot_versions:
+          platform = f'@bazel_bootlin//platforms:{arch}-linux-{cstdlib}-{version}'
+          f.write(f'bazel build --verbose_failures --platforms={platform} //test:test_cpp\n')
+          f.write(f'bazel build --verbose_failures --platforms={platform} //test:test_c\n')
 
   os.chmod(filename, 0o777)
 

test_build_all.sh

@@ -2,15 +2,17 @@
 set -e
 set -o xtrace
 
-bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:x86-64-linux-gnu-2021.11-5 //test:test_cpp
-bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:x86-64-linux-gnu-2021.11-5 //test:test_c
-bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:x86-64-linux-gnu-2022.08-1 //test:test_cpp
-bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:x86-64-linux-gnu-2022.08-1 //test:test_c
-bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:x86-64-core-i7-linux-gnu-2020.08-1 //test:test_cpp
-bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:x86-64-core-i7-linux-gnu-2020.08-1 //test:test_c
-bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:aarch64-linux-gnu-2021.11-1 //test:test_cpp
-bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:aarch64-linux-gnu-2021.11-1 //test:test_c
-bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:aarch64-linux-gnu-2020.08-1 //test:test_cpp
-bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:aarch64-linux-gnu-2020.08-1 //test:test_c
-bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:armv7-eabihf-linux-gnu-2020.08-1 //test:test_cpp
-bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:armv7-eabihf-linux-gnu-2020.08-1 //test:test_c
+bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:x86-64-linux-glibc-2021.11-5 //test:test_cpp
+bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:x86-64-linux-glibc-2021.11-5 //test:test_c
+bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:x86-64-linux-glibc-2022.08-1 //test:test_cpp
+bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:x86-64-linux-glibc-2022.08-1 //test:test_c
+bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:x86-64-core-i7-linux-glibc-2020.08-1 //test:test_cpp
+bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:x86-64-core-i7-linux-glibc-2020.08-1 //test:test_c
+bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:aarch64-linux-glibc-2021.11-1 //test:test_cpp
+bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:aarch64-linux-glibc-2021.11-1 //test:test_c
+bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:aarch64-linux-glibc-2020.08-1 //test:test_cpp
+bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:aarch64-linux-glibc-2020.08-1 //test:test_c
+bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:aarch64-linux-musl-2021.11-1 //test:test_cpp
+bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:aarch64-linux-musl-2021.11-1 //test:test_c
+bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:armv7-eabihf-linux-glibc-2020.08-1 //test:test_cpp
+bazel build --verbose_failures --platforms=@bazel_bootlin//platforms:armv7-eabihf-linux-glibc-2020.08-1 //test:test_c

toolchains/tool_wrappers/aarch64/glibc/2020.08-1/aarch64-linux-glibc-2020.08-1-ar

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2020.08-1/bin/aarch64-buildroot-linux-gnu-ar $@

toolchains/tool_wrappers/aarch64/glibc/2020.08-1/aarch64-linux-glibc-2020.08-1-cpp

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2020.08-1/bin/aarch64-buildroot-linux-gnu-cpp.br_real $@

toolchains/tool_wrappers/aarch64/glibc/2020.08-1/aarch64-linux-glibc-2020.08-1-gcc

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2020.08-1/bin/aarch64-buildroot-linux-gnu-gcc.br_real $@

toolchains/tool_wrappers/aarch64/glibc/2020.08-1/aarch64-linux-glibc-2020.08-1-gcov

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2020.08-1/bin/aarch64-buildroot-linux-gnu-gcov $@

toolchains/tool_wrappers/aarch64/glibc/2020.08-1/aarch64-linux-glibc-2020.08-1-ld

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2020.08-1/bin/aarch64-buildroot-linux-gnu-ld $@

toolchains/tool_wrappers/aarch64/glibc/2020.08-1/aarch64-linux-glibc-2020.08-1-nm

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2020.08-1/bin/aarch64-buildroot-linux-gnu-nm $@

toolchains/tool_wrappers/aarch64/glibc/2020.08-1/aarch64-linux-glibc-2020.08-1-objdump

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2020.08-1/bin/aarch64-buildroot-linux-gnu-objdump $@

toolchains/tool_wrappers/aarch64/glibc/2020.08-1/aarch64-linux-glibc-2020.08-1-strip

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2020.08-1/bin/aarch64-buildroot-linux-gnu-strip $@

toolchains/tool_wrappers/aarch64/glibc/2021.11-1/aarch64-linux-glibc-2021.11-1-ar

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2021.11-1/bin/aarch64-buildroot-linux-gnu-ar $@

toolchains/tool_wrappers/aarch64/glibc/2021.11-1/aarch64-linux-glibc-2021.11-1-cpp

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2021.11-1/bin/aarch64-buildroot-linux-gnu-cpp.br_real $@

toolchains/tool_wrappers/aarch64/glibc/2021.11-1/aarch64-linux-glibc-2021.11-1-gcc

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2021.11-1/bin/aarch64-buildroot-linux-gnu-gcc.br_real $@

toolchains/tool_wrappers/aarch64/glibc/2021.11-1/aarch64-linux-glibc-2021.11-1-gcov

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2021.11-1/bin/aarch64-buildroot-linux-gnu-gcov $@

toolchains/tool_wrappers/aarch64/glibc/2021.11-1/aarch64-linux-glibc-2021.11-1-ld

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2021.11-1/bin/aarch64-buildroot-linux-gnu-ld $@

toolchains/tool_wrappers/aarch64/glibc/2021.11-1/aarch64-linux-glibc-2021.11-1-nm

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2021.11-1/bin/aarch64-buildroot-linux-gnu-nm $@

toolchains/tool_wrappers/aarch64/glibc/2021.11-1/aarch64-linux-glibc-2021.11-1-objdump

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2021.11-1/bin/aarch64-buildroot-linux-gnu-objdump $@

toolchains/tool_wrappers/aarch64/glibc/2021.11-1/aarch64-linux-glibc-2021.11-1-strip

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-glibc-2021.11-1/bin/aarch64-buildroot-linux-gnu-strip $@

toolchains/tool_wrappers/aarch64/musl/2021.11-1/aarch64-linux-musl-2021.11-1-ar

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-musl-2021.11-1/bin/aarch64-buildroot-linux-musl-ar $@

toolchains/tool_wrappers/aarch64/musl/2021.11-1/aarch64-linux-musl-2021.11-1-cpp

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-musl-2021.11-1/bin/aarch64-buildroot-linux-musl-cpp.br_real $@

toolchains/tool_wrappers/aarch64/musl/2021.11-1/aarch64-linux-musl-2021.11-1-gcc

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-musl-2021.11-1/bin/aarch64-buildroot-linux-musl-gcc.br_real $@

toolchains/tool_wrappers/aarch64/musl/2021.11-1/aarch64-linux-musl-2021.11-1-gcov

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-musl-2021.11-1/bin/aarch64-buildroot-linux-musl-gcov $@

toolchains/tool_wrappers/aarch64/musl/2021.11-1/aarch64-linux-musl-2021.11-1-ld

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-musl-2021.11-1/bin/aarch64-buildroot-linux-musl-ld $@

toolchains/tool_wrappers/aarch64/musl/2021.11-1/aarch64-linux-musl-2021.11-1-nm

@@ -0,0 +1,2 @@
+#!/bin/bash
+exec external/aarch64-linux-musl-2021.11-1/bin/aarch64-buildroot-linux-musl-nm $@