Merge pull request #6360 from Arthapz/update-module-policies

(C++ modules support) Update module policies

9 files changed, 71 insertions, 23 deletions

diff --git a/tests/projects/c++/modules/test_headerunits.lua b/tests/projects/c++/modules/test_headerunits.lua
index d34c70757..264cca6e6 100644
--- a/tests/projects/c++/modules/test_headerunits.lua
+++ b/tests/projects/c++/modules/test_headerunits.lua
@@ -22,12 +22,12 @@ function main(t)
         local clang = find_tool("clang", {version = true})
         if clang and clang.version and semver.compare(clang.version, "15.0") >= 0 then
             -- clang headerunit are bugged
-            -- os.exec("xmake f --toolchain=clang -c --yes --policies=build.c++.modules.std:n,build.c++.clang.fallbackscanner")
+            -- os.exec("xmake f --toolchain=clang -c --yes --policies=build.c++.modules.std:n,build.c++.modules.fallbackscanner:y")
             -- _build()
             -- if semver.compare(clang.version, "17.0") >= 0 then
             --     os.exec("xmake clean -a")
             --     -- clang-scan-deps dependency detection doesn't support header units atm
-            --     os.exec("xmake f --toolchain=clang --runtimes=c++_shared -c --yes --policies=build.c++.modules.std:n,build.c++.clang.fallbackscanner")
+            --     os.exec("xmake f --toolchain=clang --runtimes=c++_shared -c --yes --policies=build.c++.modules.std:n,build.c++.modules.fallbackscanner:y")
             --     _build()
             -- end
         end
@@ -40,14 +40,14 @@ function main(t)
         end
     elseif is_subhost("msys") then
         -- on windows, mingw modulemapper doesn't handle headeunit path correctly, but it's working with mingw on macOS / Linux
-        -- os.exec("xmake f -c -p mingw --yes --policies=build.c++.modules.std:n,build.c++.gcc.fallbackscanner")
+        -- os.exec("xmake f -c -p mingw --yes --policies=build.c++.modules.std:n,build.c++.modules.fallbackscanner:y")
         -- _build()
     elseif is_host("linux") then
         local gcc = find_tool("gcc", {version = true})
         if gcc and gcc.version and semver.compare(gcc.version, "11.0") >= 0 and
             os.arch() ~= "arm64" then -- gcc/arm64: internal compiler error: in core_vals, at cp/module.cc:6108
             -- gcc dependency detection doesn't support header units atm
-            os.exec("xmake f -c --yes --policies=build.c++.modules.std:n,build.c++.gcc.fallbackscanner")
+            os.exec("xmake f -c --yes --policies=build.c++.modules.std:n,build.c++.modules.fallbackscanner:y")
             _build()
         end
         local clang = find_tool("clang", {version = true})
@@ -55,14 +55,14 @@ function main(t)
             if semver.compare(clang.version, "19.0") >= 0 then
                 os.exec("xmake clean -a")
                 -- clang-scan-deps dependency detection doesn't support header units atm
-                os.exec("xmake f --toolchain=clang -c --yes --policies=build.c++.modules.std:n,build.c++.clang.fallbackscanner")
+                os.exec("xmake f --toolchain=clang -c --yes --policies=build.c++.modules.std:n,build.c++.modules.fallbackscanner:y")
                 _build()
             end
             -- libc++ headerunit are bugged
             -- if semver.compare(clang.version, "17.0") >= 0 then
             --     os.exec("xmake clean -a")
             --     -- clang-scan-deps dependency detection doesn't support header units atm
-            --     os.exec("xmake f --toolchain=clang --runtimes=c++_shared -c --yes --policies=build.c++.modules.std:n,build.c++.clang.fallbackscanner")
+            --     os.exec("xmake f --toolchain=clang --runtimes=c++_shared -c --yes --policies=build.c++.modules.std:n,build.c++.modules.fallbackscanner:y")
             --     _build()
             -- end
         end
diff --git a/xmake/core/project/policy.lua b/xmake/core/project/policy.lua
index c4da9fdd3..005775517 100644
--- a/xmake/core/project/policy.lua
+++ b/xmake/core/project/policy.lua
@@ -76,22 +76,30 @@ function policy.policies()
             ["build.c++.modules.std"]             = {description = "Enable std modules.", default = true, type = "boolean"},
             -- Enable unreferenced and non-public named module culling
             ["build.c++.modules.culling"]         = {description = "Enable unrefereced and non-public named module culling.", default = true, type = "boolean"},
-            -- Try to reuse compiled module bmi file if targets flags permit it
-            ["build.c++.modules.tryreuse"]        = {description = "Try to reuse compiled module if possible.", default = true, type = "boolean"},
-            -- Enable module taking defines acbount for bmi reuse discrimination
+            -- Always reuse compiled module bmi file
+            ["build.c++.modules.reuse"]           = {description = "Reuse compiled module artifacts if possible.", default = true, type = "boolean"},
+            ["build.c++.modules.tryreuse"]        = {description = "Try to reuse compiled module if possible. (deprecated)", default = false, type = "boolean"},
+            -- If target will not reuse modules from target deps if defines are different
+            ["build.c++.modules.reuse.strict"]          = {description = "Enable strict defines comparison when trying to reuse module.", default = false, type = "boolean"},
             ["build.c++.modules.tryreuse.discriminate_on_defines"] = {description = "Enable defines module reuse discrimination.", default = false, type = "boolean"},
+            -- Force C++ modules fallback dependency scanner for all compilers
+            ["build.c++.modules.fallbackscanner"]       = {description = "Force fallback module dependency scanner.", default = false, type = "boolean"},
             -- Force C++ modules fallback dependency scanner for clang
-            ["build.c++.clang.fallbackscanner"]   = {description = "Force clang fallback module dependency scanner.", default = false, type = "boolean"},
+            ["build.c++.modules.clang.fallbackscanner"] = {description = "Force clang fallback module dependency scanner.", default = false, type = "boolean"},
+            ["build.c++.clang.fallbackscanner"]         = {description = "Force clang fallback module dependency scanner. (deprecated)", default = false, type = "boolean"},
             -- Force C++ modules fallback dependency scanner for msvc
-            ["build.c++.msvc.fallbackscanner"]    = {description = "Force msvc fallback module dependency scanner.", default = false, type = "boolean"},
-            -- Set the default vs runtime, e.g. MT, MD
-            ["build.c++.msvc.runtime"]            = {description = "Set the default vs runtime.", type = "string", values = {"MT", "MD"}},
+            ["build.c++.modules.msvc.fallbackscanner"]  = {description = "Force msvc fallback module dependency scanner.", default = false, type = "boolean"},
+            ["build.c++.msvc.fallbackscanner"]          = {description = "Force msvc fallback module dependency scanner. (deprecated)", default = false, type = "boolean"},
             -- Force C++ modules fallback dependency scanner for gcc
-            ["build.c++.gcc.fallbackscanner"]     = {description = "Force gcc fallback module dependency scanner.", default = false, type = "boolean"},
+            ["build.c++.modules.gcc.fallbackscanner"]   = {description = "Force gcc fallback module dependency scanner.", default = false, type = "boolean"},
+            ["build.c++.gcc.fallbackscanner"]           = {description = "Force gcc fallback module dependency scanner. (deprecated)", default = false, type = "boolean"},
             -- Force to enable new cxx11 abi in C++ modules for gcc
             -- If in the future, gcc can support it well, we'll turn it on by default
             -- https://github.com/xmake-io/xmake/issues/3855
-            ["build.c++.gcc.modules.cxx11abi"]    = {description = "Force to enable new cxx11 abi in C++ modules for gcc.", type = "boolean"},
+            ["build.c++.modules.gcc.cxx11abi"]    = {description = "Force to enable new cxx11 abi in C++ modules for gcc.", type = "boolean"},
+            ["build.c++.gcc.modules.cxx11abi"]    = {description = "Force to enable new cxx11 abi in C++ modules for gcc. (deprecated)", type = "boolean", default = false},
+            -- Set the default vs runtime, e.g. MT, MD
+            ["build.c++.msvc.runtime"]            = {description = "Set the default vs runtime.", type = "string", values = {"MT", "MD"}},
             -- Enable cuda device link
             ["build.cuda.devlink"]                = {description = "Enable Cuda devlink.", type = "boolean"},
             -- Enable build jobgraph
diff --git a/xmake/rules/c++/modules/clang/scanner.lua b/xmake/rules/c++/modules/clang/scanner.lua
index 5b7d10658..2b4738f65 100644
--- a/xmake/rules/c++/modules/clang/scanner.lua
+++ b/xmake/rules/c++/modules/clang/scanner.lua
@@ -32,7 +32,9 @@ function generate_dependency_for(target, sourcefile, opt)
     local changed = false
     local dependfile = target:dependfile(sourcefile)
     local flags = compinst:compflags({sourcefile = sourcefile, target = target}) or {}
-    local fileconfig = target:fileconfig(sourcefile)
+    local fallbackscanner = target:policy("build.c++.modules.fallbackscanner") or
+                            target:policy("build.c++.modules.clang.fallbackscanner") or
+                            target:policy("build.c++.clang.fallbackscanner")
 
     depend.on_changed(function()
         if opt.progress then
@@ -42,7 +44,7 @@ function generate_dependency_for(target, sourcefile, opt)
         local outputdir = support.get_outputdir(target, sourcefile)
         local jsonfile = path.translate(path.join(outputdir, path.filename(sourcefile) .. ".json"))
         local has_clangscandepssupport = support.has_clangscandepssupport(target)
-        if has_clangscandepssupport and not target:policy("build.c++.clang.fallbackscanner") then
+        if has_clangscandepssupport and not fallbackscanner then
             -- We need absolute path of clang to use clang-scan-deps
             -- See https://clang.llvm.org/docs/StandardCPlusPlusModules.html#possible-issues-failed-to-find-system-headers
             local clang_path = compinst:program()
diff --git a/xmake/rules/c++/modules/clang/support.lua b/xmake/rules/c++/modules/clang/support.lua
index adfd5730c..08a453ffa 100644
--- a/xmake/rules/c++/modules/clang/support.lua
+++ b/xmake/rules/c++/modules/clang/support.lua
@@ -149,7 +149,9 @@ function strip_flags(target, flags)
         "-cxx-isystem",
         "-Q",
     }
-    if not target:policy("build.c++.modules.tryreuse.discriminate_on_defines") then
+    local strict = target:policy("build.c++.modules.reuse.strict") or
+                   target:policy("build.c++.modules.tryreuse.discriminate_on_defines")
+    if not strict then
         table.join2(strippable_flags, {"-D", "-U"})
     end
     local output = {}
diff --git a/xmake/rules/c++/modules/config.lua b/xmake/rules/c++/modules/config.lua
index a39e4c4e0..4edbe1e1b 100644
--- a/xmake/rules/c++/modules/config.lua
+++ b/xmake/rules/c++/modules/config.lua
@@ -25,6 +25,10 @@ function main(target)
     -- we disable to build across targets in parallel, because the source files may depend on other target modules
     -- @see https://github.com/xmake-io/xmake/issues/1858
     if support.contains_modules(target) then
+
+        -- unity build can't work with modules
+        assert(not target:rule("c++.unity_build"), "C++ unity build is not compatible with C++ modules")
+
         -- @note this will cause cross-parallel builds to be disabled for all sub-dependent targets,
         -- even if some sub-targets do not contain C++ modules.
         --
@@ -45,6 +49,26 @@ function main(target)
         -- mark this target with modules
         target:data_set("cxx.has_modules", true)
 
+        -- warn about deprecated policies
+        if target:policy("build.c++.gcc.modules.cxx11abi") then
+            wprint("build.c++.gcc.modules.cxx11abi is deprecated, please use build.c++.modules.gcc.cxx11abi")
+        end
+        if target:policy("build.c++.clang.fallbackscanner") then
+            wprint("build.c++.clang.fallbackscanner is deprecated, please use build.c++.modules.clang.fallbackscanner")
+        end
+        if target:policy("build.c++.gcc.fallbackscanner") then
+            wprint("build.c++.gcc.fallbackscanner is deprecated, please use build.c++.modules.gcc.fallbackscanner")
+        end
+        if target:policy("build.c++.msvc.fallbackscanner") then
+            wprint("build.c++.msvc.fallbackscanner is deprecated, please use build.c++.modules.msvc.fallbackscanner")
+        end
+        if target:policy("build.c++.modules.tryreuse") then
+            wprint("build.c++.modules.tryreuse is deprecated, please use build.c++.modules.reuse")
+        end
+        if target:policy("build.c++.modules.tryreuse.discriminate_on_defines") then
+            wprint("build.c++.modules.tryreuse.discriminate_on_defines is deprecated, please use build.c++.modules.reuse.strict")
+        end
+
         -- moduleonly modules are implicitly public
         if target:is_moduleonly() then
             local sourcebatch = target:sourcebatches()["c++.build.modules.builder"]
diff --git a/xmake/rules/c++/modules/gcc/scanner.lua b/xmake/rules/c++/modules/gcc/scanner.lua
index 1496d17dd..8abf08c44 100644
--- a/xmake/rules/c++/modules/gcc/scanner.lua
+++ b/xmake/rules/c++/modules/gcc/scanner.lua
@@ -37,6 +37,9 @@ function generate_dependency_for(target, sourcefile, opt)
     local dependfile = target:dependfile(sourcefile)
     local flags = compinst:compflags({sourcefile = sourcefile, target = target}) or {}
     local changed = false
+    local fallbackscanner = target:policy("build.c++.modules.fallbackscanner") or
+                            target:policy("build.c++.modules.gcc.fallbackscanner") or
+                            target:policy("build.c++.gcc.fallbackscanner")
 
     depend.on_changed(function()
         if opt.progress then
@@ -46,7 +49,7 @@ function generate_dependency_for(target, sourcefile, opt)
         local outputdir = support.get_outputdir(target, sourcefile)
         local jsonfile = path.translate(path.join(outputdir, path.filename(sourcefile) .. ".json"))
         local has_depsflags = depsformatflag and depsfileflag and depstargetflag
-        if has_depsflags and not target:policy("build.c++.gcc.fallbackscanner") then
+        if has_depsflags and not fallbackscanner then
             local ifile = path.translate(path.join(outputdir, path.filename(sourcefile) .. ".i"))
             local dfile = path.translate(path.join(outputdir, path.filename(sourcefile) .. ".d"))
             local compflags = table.join(flags or {}, baselineflags, {sourcefile, "-MT", jsonfile, "-MD", "-MF", dfile, depsformatflag, depsfileflag .. jsonfile, depstargetflag .. target:objectfile(sourcefile), "-o", ifile})
diff --git a/xmake/rules/c++/modules/gcc/support.lua b/xmake/rules/c++/modules/gcc/support.lua
index 52d8af79f..792e975f5 100644
--- a/xmake/rules/c++/modules/gcc/support.lua
+++ b/xmake/rules/c++/modules/gcc/support.lua
@@ -60,7 +60,9 @@ function load(target)
     -- @see https://github.com/xmake-io/xmake/issues/2716#issuecomment-1225057760
     -- https://github.com/xmake-io/xmake/issues/3855
 
-    if target:policy("build.c++.gcc.modules.cxx11abi") then
+    local cxx11abi = target:policy("build.c++.modules.gcc.cxx11abi") or
+                     target:policy("build.c++.gcc.modules.cxx11abi")
+    if cxx11abi then
         target:add("cxxflags", "-D_GLIBCXX_USE_CXX11_ABI=1")
     else
         target:add("cxxflags", "-D_GLIBCXX_USE_CXX11_ABI=0")
@@ -81,7 +83,9 @@ function strip_flags(target, flags)
         "-Q",
         "-fmodule-mapper",
     }
-    if not target:policy("build.c++.modules.tryreuse.discriminate_on_defines") then
+    local strict = target:policy("build.c++.modules.reuse.strict") or
+                   target:policy("build.c++.modules.tryreuse.discriminate_on_defines")
+    if not strict then
         table.join2(strippable_flags, {"-D", "-U"})
     end
     local output = {}
diff --git a/xmake/rules/c++/modules/msvc/scanner.lua b/xmake/rules/c++/modules/msvc/scanner.lua
index b4d68df37..07342a55e 100644
--- a/xmake/rules/c++/modules/msvc/scanner.lua
+++ b/xmake/rules/c++/modules/msvc/scanner.lua
@@ -38,13 +38,16 @@ function generate_dependency_for(target, sourcefile, opt)
     local compinst = target:compiler("cxx")
     local flags = compinst:compflags({sourcefile = sourcefile, target = target}) or {}
     local changed = false
+    local fallbackscanner = target:policy("build.c++.modules.fallbackscanner") or
+                            target:policy("build.c++.modules.msvc.fallbackscanner") or
+                            target:policy("build.c++.msvc.fallbackscanner")
 
     depend.on_changed(function ()
         progress.show(opt.progress, "${color.build.target}<%s> generating.module.deps %s", target:fullname(), sourcefile)
         local outputdir = support.get_outputdir(target, sourcefile)
 
         local jsonfile = path.join(outputdir, path.filename(sourcefile) .. ".module.json")
-        if scandependenciesflag and not target:policy("build.c++.msvc.fallbackscanner") then
+        if scandependenciesflag and not fallbackscanner then
             local dependency_flags = {jsonfile, sourcefile, ifcoutputflag, outputdir, "-Fo" .. target:objectfile(sourcefile)}
             local compflags = table.join(flags, common_flags, dependency_flags)
             os.vrunv(compinst:program(), winos.cmdargv(compflags), {envs = msvc:runenvs()})
diff --git a/xmake/rules/c++/modules/msvc/support.lua b/xmake/rules/c++/modules/msvc/support.lua
index f2b07b999..0da24501f 100644
--- a/xmake/rules/c++/modules/msvc/support.lua
+++ b/xmake/rules/c++/modules/msvc/support.lua
@@ -94,7 +94,9 @@ function strip_flags(target, flags)
         "analyze",
         "?",
     }
-    if not target:policy("build.c++.modules.tryreuse.discriminate_on_defines") then
+    local strict = target:policy("build.c++.modules.reuse.strict") or
+                   target:policy("build.c++.modules.tryreuse.discriminate_on_defines")
+    if not strict then
         table.join2(strippable_flags, {"D", "U"})
     end
     local output = {}