From 78bc3cd0364f432b08d49c047c823f302f80aa24 Mon Sep 17 00:00:00 2001
From: Thulio Ferraz Assis <3149049+f0rmiga@users.noreply.github.com>
Date: Mon, 29 Apr 2024 11:36:45 -0700
Subject: [PATCH] feat: add target_settings so we can do config transitions
 (#173)

---
 docs/defs.md       |  3 ++-
 toolchain/defs.bzl | 12 ++++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/docs/defs.md b/docs/defs.md
index 36c3d6e..98eb30f 100644
--- a/docs/defs.md
+++ b/docs/defs.md
@@ -10,7 +10,7 @@ This module provides the definitions for registering a GCC toolchain for C and C
 <pre>
 gcc_toolchain(<a href="#gcc_toolchain-name">name</a>, <a href="#gcc_toolchain-binary_prefix">binary_prefix</a>, <a href="#gcc_toolchain-extra_cflags">extra_cflags</a>, <a href="#gcc_toolchain-extra_cxxflags">extra_cxxflags</a>, <a href="#gcc_toolchain-extra_fflags">extra_fflags</a>, <a href="#gcc_toolchain-extra_ldflags">extra_ldflags</a>,
               <a href="#gcc_toolchain-gcc_toolchain_workspace_name">gcc_toolchain_workspace_name</a>, <a href="#gcc_toolchain-includes">includes</a>, <a href="#gcc_toolchain-repo_mapping">repo_mapping</a>, <a href="#gcc_toolchain-sysroot">sysroot</a>, <a href="#gcc_toolchain-target_arch">target_arch</a>,
-              <a href="#gcc_toolchain-target_compatible_with">target_compatible_with</a>, <a href="#gcc_toolchain-toolchain_files_repository_name">toolchain_files_repository_name</a>)
+              <a href="#gcc_toolchain-target_compatible_with">target_compatible_with</a>, <a href="#gcc_toolchain-target_settings">target_settings</a>, <a href="#gcc_toolchain-toolchain_files_repository_name">toolchain_files_repository_name</a>)
 </pre>
 
 
@@ -32,6 +32,7 @@ gcc_toolchain(<a href="#gcc_toolchain-name">name</a>, <a href="#gcc_toolchain-bi
 | <a id="gcc_toolchain-sysroot"></a>sysroot |  A sysroot to be used as the logical build root.   | String | required |  |
 | <a id="gcc_toolchain-target_arch"></a>target_arch |  The target architecture this toolchain produces. E.g. x86_64.   | String | required |  |
 | <a id="gcc_toolchain-target_compatible_with"></a>target_compatible_with |  contraint_values passed to target_compatible_with of the toolchain. {target_arch} is rendered to the target_arch attribute value.   | List of strings | optional | <code>["@platforms//os:linux", "@platforms//cpu:{target_arch}"]</code> |
+| <a id="gcc_toolchain-target_settings"></a>target_settings |  config_settings passed to target_compatible_with of the toolchain. {target_arch} is rendered to the target_arch attribute value.   | List of strings | optional | <code>[]</code> |
 | <a id="gcc_toolchain-toolchain_files_repository_name"></a>toolchain_files_repository_name |  The name of the repository containing the toolchain files.   | String | required |  |
 
 
diff --git a/toolchain/defs.bzl b/toolchain/defs.bzl
index 46d1fb0..9df306b 100644
--- a/toolchain/defs.bzl
+++ b/toolchain/defs.bzl
@@ -55,9 +55,15 @@ def _gcc_toolchain_impl(rctx):
         for v in rctx.attr.target_compatible_with
     ]
 
+    target_settings = [
+        v.format(target_arch = target_arch)
+        for v in rctx.attr.target_settings
+    ]
+
     rctx.file("BUILD.bazel", _TOOLCHAIN_BUILD_FILE_CONTENT.format(
         gcc_toolchain_workspace_name = rctx.attr.gcc_toolchain_workspace_name,
         target_compatible_with = str(target_compatible_with),
+        target_settings = str(target_settings),
         toolchain_files_repository_name = rctx.attr.toolchain_files_repository_name,
 
         # Sysroot
@@ -135,6 +141,11 @@ _FEATURE_ATTRS = {
         doc = "contraint_values passed to target_compatible_with of the toolchain. {target_arch} is rendered to the target_arch attribute value.",
         mandatory = False,
     ),
+    "target_settings": attr.string_list(
+        default = [],
+        doc = "config_settings passed to target_compatible_with of the toolchain. {target_arch} is rendered to the target_arch attribute value.",
+        mandatory = False,
+    ),
     "toolchain_files_repository_name": attr.string(
         doc = "The name of the repository containing the toolchain files.",
         mandatory = True,
@@ -570,6 +581,7 @@ toolchain(
         "@platforms//cpu:x86_64",
     ],
     target_compatible_with = {target_compatible_with},
+    target_settings = {target_settings},
     toolchain = ":_cc_toolchain",
     toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",
 )