feat(C++ modules) add build.c++.modules.non_cascading_changes policy to enable bmi hash comparison as incremental build optimisation for clang

1 files changed, 10 insertions, 9 deletions

diff --git a/xmake/rules/c++/modules/builder.lua b/xmake/rules/c++/modules/builder.lua
index b84d5d23e..a1c93a35f 100644
--- a/xmake/rules/c++/modules/builder.lua
+++ b/xmake/rules/c++/modules/builder.lua
@@ -180,6 +180,15 @@ function should_build(target, module)
         local old_dependinfo = target:is_rebuilt() and {} or (depend.load(dependfile) or {})
         old_dependinfo.files = {module.sourcefile}
 
+        -- need build this object?
+        local dryrun = option.get("dry-run")
+        if dryrun or depend.is_changed(old_dependinfo, dependinfo) then
+            depend.save(dependinfo, dependfile)
+            memcache:set2(target:fullname(), "should_build_" .. module.sourcefile, true)
+            profiler.leave(target:fullname(), "c++ modules", "builder", "check if " .. (module.name or module.sourcefile) .. " should be rebuilt")
+            return true
+        end
+
         -- force rebuild a module if any of its module dependency is rebuilt
         for dep_name, dep_module in table.orderpairs(module.deps) do
             local mapped_dep = mapper.get(target, dep_module.headerunit and dep_name .. dep_module.key or dep_name)
@@ -188,18 +197,10 @@ function should_build(target, module)
                 depend.save(dependinfo, dependfile)
                 memcache:set2(target:fullname(), "should_build_" .. module.sourcefile, true)
                 profiler.leave(target:fullname(), "c++ modules", "builder", "check if " .. (module.name or module.sourcefile) .. " should be rebuilt")
-                return true
+                return true, true
             end
         end
 
-        -- need build this object?
-        local dryrun = option.get("dry-run")
-        if dryrun or depend.is_changed(old_dependinfo, dependinfo) then
-            depend.save(dependinfo, dependfile)
-            memcache:set2(target:fullname(), "should_build_" .. module.sourcefile, true)
-            profiler.leave(target:fullname(), "c++ modules", "builder", "check if " .. (module.name or module.sourcefile) .. " should be rebuilt")
-            return true
-        end
         memcache:set2(target:fullname(), "should_build_" .. module.sourcefile, false)
         profiler.leave(target:fullname(), "c++ modules", "builder", "check if " .. (module.name or module.sourcefile) .. " should be rebuilt")
         return false