in "c++.build.modules" rule, add required flags to modules

1 files changed, 48 insertions, 0 deletions

diff --git a/xmake/rules/c++/modules/xmake.lua b/xmake/rules/c++/modules/xmake.lua
index ab90f67a7..9155f1a6f 100644
--- a/xmake/rules/c++/modules/xmake.lua
+++ b/xmake/rules/c++/modules/xmake.lua
@@ -57,6 +57,54 @@ rule("c++.build.modules")
             target:data_set("cxx.has_modules", true)
         end
     end)
+    before_buildcmd_files(function(target, batchcmds, sourcebatch, opt)
+        if target:data("cxx.has_modules") then
+            import("modules_support.common")
+
+            local target_clone = target:clone()
+
+            common.patch_sourcebatch(target_clone, sourcebatch, opt)
+
+            local modules = common.get_module_dependencies(target, sourcebatch, opt)
+
+            -- we need to generate modules to get their dependencies available for `get_requiresflags`
+            common.generate_headerunits_for_batchcmds(target_clone, batchcmds, sourcebatch, modules, opt)
+            common.build_modules_for_batchcmds(target_clone, batchcmds, sourcebatch, modules, opt)
+
+            -- for each module, we add required flags 
+            local module_support = common.modules_support(target)
+            for _, objectfile in ipairs(sourcebatch.objectfiles) do
+                local module = modules[objectfile]
+                if module and module.requires then
+                    local requiresflags = module_support.get_requiresflags(target, module.requires)
+                    
+                    local sourcefile = nil
+                    for _, mod in pairs(module.provides) do
+                        if mod.sourcefile then 
+                            sourcefile = mod.sourcefile
+                            break
+                        end 
+                    end
+                    if sourcefile then 
+                        target:fileconfig_add(sourcefile, {force = {cxxflags = requiresflags}})
+                    end
+                end
+            end
+
+            -- debugging values
+            local compinst = target:compiler("cxx")
+            for _, sourcefile in ipairs(sourcebatch.sourcefiles) do
+                local compflags = compinst:compflags({sourcefile = sourcefile, target = target})
+                print("source: ", sourcefile, "compflags: ", compflags)
+            end
+            local compflags = compinst:compflags({sourcefile = "src/main.cpp", target = target})
+            print("source: ", "src/main.cpp", "compflags: ", compflags)
+
+        else
+            -- avoid duplicate linking of object files of non-module programs
+            sourcebatch.objectfiles = {}
+        end
+    end)
 
 -- build modules
 rule("c++.build.modules.builder")