Fix conflicting actions for C++20 modules info files in PIC/non-PIC b… (#834)

…uilds

Fix https://github.com/bazelbuild/rules_cc/issues/833

Closes #834

COPYBARA_INTEGRATE_REVIEW=https://github.com/bazelbuild/rules_cc/pull/834 from PikachuHyA:fix_module_json_conflict 9683f3aa78798665ebdf59aeaa5edfb46b4edffe
PiperOrigin-RevId: 962293343
Change-Id: I7c7b13687004126310f004359afc05970e31d506

cc/private/compile/compile.bzl

diff --git a/cc/private/compile/compile.bzl b/cc/private/compile/compile.bzl
index d1ca4ad..56b9aed 100644
--- a/cc/private/compile/compile.bzl
+++ b/cc/private/compile/compile.bzl
@@ -673,6 +673,17 @@
     direct_module_files = []
     source_to_module_file_map = {}
     source_to_ddi_file_map = {}
+
+    # The modules info file must be distinct between PIC and non-PIC builds,
+    # otherwise the PIC and non-PIC aggregate-ddi actions would both write to
+    # the same output, causing a conflicting-actions error.
+    modules_info_output_name = label.name
+    if use_pic:
+        modules_info_output_name = _cc_internal.get_artifact_name_for_category(
+            cc_toolchain = cc_toolchain,
+            category = artifact_category.PIC_FILE,
+            output_name = modules_info_output_name,
+        )
     modules_info_file = _get_compile_output_file(
         action_construction_context,
         label,
@@ -680,7 +691,7 @@
         output_name = _cc_internal.get_artifact_name_for_category(
             cc_toolchain = cc_toolchain,
             category = artifact_category.CPP_MODULES_INFO,
-            output_name = label.name,
+            output_name = modules_info_output_name,
         ),
     )
     if use_pic: