# What: teach `rules_rs` that `windows-gnullvm` is a distinct Windows exec ABI.
# Scope: experimental platform/toolchain naming only; no Cargo target changes.

diff --git a/rs/experimental/platforms/triples.bzl b/rs/experimental/platforms/triples.bzl
--- a/rs/experimental/platforms/triples.bzl
+++ b/rs/experimental/platforms/triples.bzl
@@ -30,7 +30,9 @@ SUPPORTED_EXEC_TRIPLES = [
     "x86_64-unknown-linux-gnu",
     "aarch64-unknown-linux-gnu",
     "x86_64-pc-windows-msvc",
+    "x86_64-pc-windows-gnullvm",
     "aarch64-pc-windows-msvc",
+    "aarch64-pc-windows-gnullvm",
     "x86_64-apple-darwin",
     "aarch64-apple-darwin",
 ]
diff --git a/rs/experimental/toolchains/declare_rustc_toolchains.bzl b/rs/experimental/toolchains/declare_rustc_toolchains.bzl
--- a/rs/experimental/toolchains/declare_rustc_toolchains.bzl
+++ b/rs/experimental/toolchains/declare_rustc_toolchains.bzl
@@ -9,6 +9,11 @@ def _channel(version):
     if version.startswith("beta"):
         return "beta"
     return "stable"
+
+def _exec_triple_suffix(exec_triple):
+    if exec_triple.system == "windows":
+        return "{}_{}_{}".format(exec_triple.system, exec_triple.arch, exec_triple.abi)
+    return "{}_{}".format(exec_triple.system, exec_triple.arch)
 
 def _rustc_flags_to_select(rustc_flags_by_triple):
     return select(
@@ -31,15 +36,14 @@ def declare_rustc_toolchains(
 
     for triple in execs:
         exec_triple = _parse_triple(triple)
-        triple_suffix = exec_triple.system + "_" + exec_triple.arch
+        triple_suffix = _exec_triple_suffix(exec_triple)
 
         rustc_repo_label = "@rustc_{}_{}//:".format(triple_suffix, version_key)
         cargo_repo_label = "@cargo_{}_{}//:".format(triple_suffix, version_key)
         clippy_repo_label = "@clippy_{}_{}//:".format(triple_suffix, version_key)
 
-        rust_toolchain_name = "{}_{}_{}_rust_toolchain".format(
-            exec_triple.system,
-            exec_triple.arch,
+        rust_toolchain_name = "{}_{}_rust_toolchain".format(
+            triple_suffix,
             version_key,
         )
 
@@ -116,11 +120,8 @@ def declare_rustc_toolchains(
             target_key = sanitize_triple(target_triple)
 
             native.toolchain(
-                name = "{}_{}_to_{}_{}".format(exec_triple.system, exec_triple.arch, target_key, version_key),
-                exec_compatible_with = [
-                    "@platforms//os:" + exec_triple.system,
-                    "@platforms//cpu:" + exec_triple.arch,
-                ],
+                name = "{}_to_{}_{}".format(triple_suffix, target_key, version_key),
+                exec_compatible_with = triple_to_constraint_set(triple),
                 target_compatible_with = triple_to_constraint_set(target_triple),
                 target_settings = [
                     "@rules_rust//rust/toolchain/channel:" + channel,
diff --git a/rs/experimental/toolchains/declare_rustfmt_toolchains.bzl b/rs/experimental/toolchains/declare_rustfmt_toolchains.bzl
--- a/rs/experimental/toolchains/declare_rustfmt_toolchains.bzl
+++ b/rs/experimental/toolchains/declare_rustfmt_toolchains.bzl
@@ -1,7 +1,12 @@
 load("@rules_rust//rust:toolchain.bzl", "rustfmt_toolchain")
 load("@rules_rust//rust/platform:triple.bzl", _parse_triple = "triple")
-load("//rs/experimental/platforms:triples.bzl", "SUPPORTED_EXEC_TRIPLES")
+load("//rs/experimental/platforms:triples.bzl", "SUPPORTED_EXEC_TRIPLES", "triple_to_constraint_set")
 load("//rs/experimental/toolchains:toolchain_utils.bzl", "sanitize_version")
+
+def _exec_triple_suffix(exec_triple):
+    if exec_triple.system == "windows":
+        return "{}_{}_{}".format(exec_triple.system, exec_triple.arch, exec_triple.abi)
+    return "{}_{}".format(exec_triple.system, exec_triple.arch)
 
 def _channel(version):
     if version.startswith("nightly"):
@@ -22,14 +27,13 @@ def declare_rustfmt_toolchains(
 
     for triple in execs:
         exec_triple = _parse_triple(triple)
-        triple_suffix = exec_triple.system + "_" + exec_triple.arch
+        triple_suffix = _exec_triple_suffix(exec_triple)
 
         rustc_repo_label = "@rustc_{}_{}//:".format(triple_suffix, version_key)
         rustfmt_repo_label = "@rustfmt_{}_{}//:".format(triple_suffix, rustfmt_version_key)
 
-        rustfmt_toolchain_name = "{}_{}_{}_rustfmt_toolchain".format(
-            exec_triple.system,
-            exec_triple.arch,
+        rustfmt_toolchain_name = "{}_{}_rustfmt_toolchain".format(
+            triple_suffix,
             version_key,
         )
 
@@ -43,11 +47,8 @@ def declare_rustfmt_toolchains(
         )
 
         native.toolchain(
-            name = "{}_{}_rustfmt_{}".format(exec_triple.system, exec_triple.arch, version_key),
-            exec_compatible_with = [
-                "@platforms//os:" + exec_triple.system,
-                "@platforms//cpu:" + exec_triple.arch,
-            ],
+            name = "{}_rustfmt_{}".format(triple_suffix, version_key),
+            exec_compatible_with = triple_to_constraint_set(triple),
             target_compatible_with = [],
             target_settings = [
                 "@rules_rust//rust/toolchain/channel:" + channel,
diff --git a/rs/experimental/toolchains/declare_rust_analyzer_toolchains.bzl b/rs/experimental/toolchains/declare_rust_analyzer_toolchains.bzl
--- a/rs/experimental/toolchains/declare_rust_analyzer_toolchains.bzl
+++ b/rs/experimental/toolchains/declare_rust_analyzer_toolchains.bzl
@@ -4,7 +4,7 @@ load(
     "@rules_rust//rust/private:repository_utils.bzl",
     "includes_rust_analyzer_proc_macro_srv",
 )
-load("//rs/experimental/platforms:triples.bzl", "SUPPORTED_EXEC_TRIPLES")
+load("//rs/experimental/platforms:triples.bzl", "SUPPORTED_EXEC_TRIPLES", "triple_to_constraint_set")
 load("//rs/experimental/toolchains:toolchain_utils.bzl", "sanitize_version")
 
 def _channel(version):
@@ -13,6 +13,11 @@ def _channel(version):
     if version.startswith("beta"):
         return "beta"
     return "stable"
+
+def _exec_triple_suffix(exec_triple):
+    if exec_triple.system == "windows":
+        return "{}_{}_{}".format(exec_triple.system, exec_triple.arch, exec_triple.abi)
+    return "{}_{}".format(exec_triple.system, exec_triple.arch)
 
 def _parse_version(version):
     if "/" in version:
@@ -31,15 +36,14 @@ def declare_rust_analyzer_toolchains(
 
     for triple in execs:
         exec_triple = _parse_triple(triple)
-        triple_suffix = exec_triple.system + "_" + exec_triple.arch
+        triple_suffix = _exec_triple_suffix(exec_triple)
 
         rustc_repo_label = "@rustc_{}_{}//:".format(triple_suffix, rust_analyzer_version_key)
         rust_analyzer_repo_label = "@rust_analyzer_{}_{}//:".format(triple_suffix, rust_analyzer_version_key)
         rust_src_repo_label = "@rust_src_{}//lib/rustlib/src:rustc_srcs".format(rust_analyzer_version_key)
 
-        rust_analyzer_toolchain_name = "{}_{}_{}_rust_analyzer_toolchain".format(
-            exec_triple.system,
-            exec_triple.arch,
+        rust_analyzer_toolchain_name = "{}_{}_rust_analyzer_toolchain".format(
+            triple_suffix,
             version_key,
         )
 
@@ -57,11 +61,8 @@ def declare_rust_analyzer_toolchains(
         rust_analyzer_toolchain(**rust_analyzer_toolchain_kwargs)
 
         native.toolchain(
-            name = "{}_{}_rust_analyzer_{}".format(exec_triple.system, exec_triple.arch, version_key),
-            exec_compatible_with = [
-                "@platforms//os:" + exec_triple.system,
-                "@platforms//cpu:" + exec_triple.arch,
-            ],
+            name = "{}_rust_analyzer_{}".format(triple_suffix, version_key),
+            exec_compatible_with = triple_to_constraint_set(triple),
             target_compatible_with = [],
             target_settings = [
                 "@rules_rust//rust/toolchain/channel:" + channel,
diff --git a/rs/experimental/toolchains/module_extension.bzl b/rs/experimental/toolchains/module_extension.bzl
--- a/rs/experimental/toolchains/module_extension.bzl
+++ b/rs/experimental/toolchains/module_extension.bzl
@@ -39,6 +39,11 @@ def _normalize_arch_name(arch):
         return "aarch64"
     return arch
 
+def _exec_triple_suffix(exec_triple):
+    if exec_triple.system == "windows":
+        return "{}_{}_{}".format(exec_triple.system, exec_triple.arch, exec_triple.abi)
+    return "{}_{}".format(exec_triple.system, exec_triple.arch)
+
 def _sanitize_path_fragment(path):
     return path.replace("/", "_").replace(":", "_")
 
@@ -209,7 +214,7 @@ def _toolchains_impl(mctx):
         for triple in SUPPORTED_EXEC_TRIPLES:
             exec_triple = _parse_triple(triple)
 
-            triple_suffix = exec_triple.system + "_" + exec_triple.arch
+            triple_suffix = _exec_triple_suffix(exec_triple)
             rustc_name = "rustc_{}_{}".format(triple_suffix, version_key)
 
             rustc_repository(
@@ -258,7 +263,7 @@ def _toolchains_impl(mctx):
 
         for triple in SUPPORTED_EXEC_TRIPLES:
             exec_triple = _parse_triple(triple)
-            triple_suffix = exec_triple.system + "_" + exec_triple.arch
+            triple_suffix = _exec_triple_suffix(exec_triple)
 
             rustfmt_repository(
                 name = "rustfmt_{}_{}".format(triple_suffix, version_key),
@@ -282,7 +287,7 @@ def _toolchains_impl(mctx):
 
         for triple in SUPPORTED_EXEC_TRIPLES:
             exec_triple = _parse_triple(triple)
-            triple_suffix = exec_triple.system + "_" + exec_triple.arch
+            triple_suffix = _exec_triple_suffix(exec_triple)
 
             rust_analyzer_repository(
                 name = "rust_analyzer_{}_{}".format(triple_suffix, version_key),