Merge pull request #3255 from Arthapz/improve-clang-modules-support-with-libc++

improve clang libc++ module support

31 files changed, 180 insertions, 119 deletions

diff --git a/tests/projects/c++/modules/class/xmake.lua b/tests/projects/c++/modules/class/xmake.lua
index 6d6eaddee..42da78369 100644
--- a/tests/projects/c++/modules/class/xmake.lua
+++ b/tests/projects/c++/modules/class/xmake.lua
@@ -1,4 +1,8 @@
+add_rules("mode.release", "mode.debug")
 set_languages("c++20")
+
 target("class")
     set_kind("binary")
     add_files("src/*.cpp", "src/*.mpp")
+
+
diff --git a/tests/projects/c++/modules/cpp_with_moduledeps/xmake.lua b/tests/projects/c++/modules/cpp_with_moduledeps/xmake.lua
index 5c7a8a6f7..6a9b3538f 100644
--- a/tests/projects/c++/modules/cpp_with_moduledeps/xmake.lua
+++ b/tests/projects/c++/modules/cpp_with_moduledeps/xmake.lua
@@ -1,10 +1,11 @@
+add_rules("mode.release", "mode.debug")
 set_languages("c++20")
 
 target("mod")
   set_kind("static")
   add_files("src/mod.mpp", "src/mod.cpp")
 
-target("main")
+target("cpp_with_moduledeps")
   set_kind("binary")
   add_deps("mod")
   add_files("src/main.cpp")
diff --git a/tests/projects/c++/modules/dependence/xmake.lua b/tests/projects/c++/modules/dependence/xmake.lua
index 6d64b49b1..4d035c42b 100644
--- a/tests/projects/c++/modules/dependence/xmake.lua
+++ b/tests/projects/c++/modules/dependence/xmake.lua
@@ -1,4 +1,7 @@
+add_rules("mode.release", "mode.debug")
 set_languages("c++20")
+
 target("dependence")
     set_kind("binary")
     add_files("src/*.cpp", "src/*.mpp")
+
diff --git a/tests/projects/c++/modules/dependence2/xmake.lua b/tests/projects/c++/modules/dependence2/xmake.lua
index 6d64b49b1..4f2905fe9 100644
--- a/tests/projects/c++/modules/dependence2/xmake.lua
+++ b/tests/projects/c++/modules/dependence2/xmake.lua
@@ -1,4 +1,6 @@
+add_rules("mode.release", "mode.debug")
 set_languages("c++20")
-target("dependence")
+
+target("dependence2")
     set_kind("binary")
     add_files("src/*.cpp", "src/*.mpp")
diff --git a/tests/projects/c++/modules/headerunits_person/xmake.lua b/tests/projects/c++/modules/headerunits_person/xmake.lua
index c9290833b..d11b49824 100644
--- a/tests/projects/c++/modules/headerunits_person/xmake.lua
+++ b/tests/projects/c++/modules/headerunits_person/xmake.lua
@@ -1,4 +1,7 @@
+add_rules("mode.release", "mode.debug")

 set_languages("c++20")

-target("hello")

+

+target("headerunits_person")

     set_kind("binary")

     add_files("src/*.cpp", "src/*.mpp")

+

diff --git a/tests/projects/c++/modules/hello with spaces/xmake.lua b/tests/projects/c++/modules/hello with spaces/xmake.lua
index 4f46b699d..4369a892f 100644
--- a/tests/projects/c++/modules/hello with spaces/xmake.lua
+++ b/tests/projects/c++/modules/hello with spaces/xmake.lua
@@ -1,5 +1,6 @@
 add_rules("mode.release", "mode.debug")
 set_languages("c++20")
-target("A hello")
+
+target("hello with spaces")
     set_kind("binary")
     add_files("src/*.cpp", "src/*.mpp")
diff --git a/tests/projects/c++/modules/hello/xmake.lua b/tests/projects/c++/modules/hello/xmake.lua
index de13fc409..4f6fdab98 100644
--- a/tests/projects/c++/modules/hello/xmake.lua
+++ b/tests/projects/c++/modules/hello/xmake.lua
@@ -1,5 +1,6 @@
 add_rules("mode.release", "mode.debug")
 set_languages("c++20")
+
 target("hello")
     set_kind("binary")
     add_files("src/*.cpp", "src/*.mpp")
diff --git a/tests/projects/c++/modules/ifdef_module/xmake.lua b/tests/projects/c++/modules/ifdef_module/xmake.lua
index ee931a801..25933a35f 100644
--- a/tests/projects/c++/modules/ifdef_module/xmake.lua
+++ b/tests/projects/c++/modules/ifdef_module/xmake.lua
@@ -1,5 +1,6 @@
 add_rules("mode.release", "mode.debug")
 set_languages("c++20")
+
 target("ifdef_module")
     set_kind("binary")
     add_files("src/*.cpp")
diff --git a/tests/projects/c++/modules/impl_unit/xmake.lua b/tests/projects/c++/modules/impl_unit/xmake.lua
index abe41d20a..991f2a895 100644
--- a/tests/projects/c++/modules/impl_unit/xmake.lua
+++ b/tests/projects/c++/modules/impl_unit/xmake.lua
@@ -1,4 +1,6 @@
+add_rules("mode.release", "mode.debug")
 set_languages("c++20")
+
 target("impl_unit")
     set_kind("binary")
     add_files("src/*.cpp", "src/*.mpp")
diff --git a/tests/projects/c++/modules/inline_and_template/xmake.lua b/tests/projects/c++/modules/inline_and_template/xmake.lua
index 4810edb85..8c981fae9 100644
--- a/tests/projects/c++/modules/inline_and_template/xmake.lua
+++ b/tests/projects/c++/modules/inline_and_template/xmake.lua
@@ -1,4 +1,7 @@
+add_rules("mode.release", "mode.debug")
 set_languages("c++20")
+
 target("inline_and_template")
     set_kind("binary")
     add_files("src/*.cpp", "src/*.mpp")
+
diff --git a/tests/projects/c++/modules/internal_partition/xmake.lua b/tests/projects/c++/modules/internal_partition/xmake.lua
index f7ca6f7cf..422292295 100644
--- a/tests/projects/c++/modules/internal_partition/xmake.lua
+++ b/tests/projects/c++/modules/internal_partition/xmake.lua
@@ -1,5 +1,6 @@
 add_rules("mode.release", "mode.debug")
 set_languages("c++20")
+
 target("internal_partition")
     set_kind("binary")
     add_files("src/*.cpp", "src/hello.mpp")
diff --git a/tests/projects/c++/modules/partitions/test.lua b/tests/projects/c++/modules/partitions/test.lua
index c18e5a1d0..e77adc4ae 100644
--- a/tests/projects/c++/modules/partitions/test.lua
+++ b/tests/projects/c++/modules/partitions/test.lua
@@ -1 +1 @@
-inherit(".test_headerunits")
+inherit(".test_stdmodules")
diff --git a/tests/projects/c++/modules/partitions/xmake.lua b/tests/projects/c++/modules/partitions/xmake.lua
index 672034947..4b575432a 100644
--- a/tests/projects/c++/modules/partitions/xmake.lua
+++ b/tests/projects/c++/modules/partitions/xmake.lua
@@ -1,4 +1,6 @@
+add_rules("mode.release", "mode.debug")
 set_languages("c++20")
-target("math")
+
+target("partition")
     set_kind("binary")
-    add_files("src/*.cpp", "src/*.mpp")
+    add_files("src/*.cpp", "src/*.mpp")
\ No newline at end of file
diff --git a/tests/projects/c++/modules/partitions2/test.lua b/tests/projects/c++/modules/partitions2/test.lua
index c18e5a1d0..e77adc4ae 100644
--- a/tests/projects/c++/modules/partitions2/test.lua
+++ b/tests/projects/c++/modules/partitions2/test.lua
@@ -1 +1 @@
-inherit(".test_headerunits")
+inherit(".test_stdmodules")
diff --git a/tests/projects/c++/modules/partitions2/xmake.lua b/tests/projects/c++/modules/partitions2/xmake.lua
index c9290833b..9e0ab37bb 100644
--- a/tests/projects/c++/modules/partitions2/xmake.lua
+++ b/tests/projects/c++/modules/partitions2/xmake.lua
@@ -1,4 +1,6 @@
+add_rules("mode.release", "mode.debug")

 set_languages("c++20")

-target("hello")

+

+target("partition2")

     set_kind("binary")

     add_files("src/*.cpp", "src/*.mpp")

diff --git a/tests/projects/c++/modules/private_module/xmake.lua b/tests/projects/c++/modules/private_module/xmake.lua
index 1930f1188..57ede6993 100644
--- a/tests/projects/c++/modules/private_module/xmake.lua
+++ b/tests/projects/c++/modules/private_module/xmake.lua
@@ -1,5 +1,6 @@
 add_rules("mode.release", "mode.debug")
 set_languages("c++20")
+
 target("private_module")
     add_rules("c++")
     set_kind("$(kind)")
diff --git a/tests/projects/c++/modules/staticlib/xmake.lua b/tests/projects/c++/modules/staticlib/xmake.lua
index 93045c18f..5a3a9f4c6 100644
--- a/tests/projects/c++/modules/staticlib/xmake.lua
+++ b/tests/projects/c++/modules/staticlib/xmake.lua
@@ -1,10 +1,11 @@
+add_rules("mode.release", "mode.debug")
 set_languages("c++20")
 
 target("mod")
     set_kind("static")
     add_files("src/mod.mpp", "src/mod.cpp")
 
-target("test")
+target("staticlib")
     set_kind("binary")
     add_deps("mod")
     add_files("src/main.cpp")
diff --git a/tests/projects/c++/modules/stdmodules/test.lua b/tests/projects/c++/modules/stdmodules/test.lua
index 0657ead56..e77adc4ae 100644
--- a/tests/projects/c++/modules/stdmodules/test.lua
+++ b/tests/projects/c++/modules/stdmodules/test.lua
@@ -1 +1 @@
-inherit(".test_msvc")
+inherit(".test_stdmodules")
diff --git a/tests/projects/c++/modules/stdmodules/xmake.lua b/tests/projects/c++/modules/stdmodules/xmake.lua
index 85e738d14..5cf4ccb9d 100644
--- a/tests/projects/c++/modules/stdmodules/xmake.lua
+++ b/tests/projects/c++/modules/stdmodules/xmake.lua
@@ -1,14 +1,15 @@
 add_rules("mode.debug", "mode.release")
-
-add_cxxflags("clang::-stdlib=libc++")
-
 set_languages("c++latest")
 
 target("mod")
     set_kind("static")
     add_files("src/*.cpp", "src/*.mpp")
 
-target("test")
+    set_policy("build.c++.clang.stdmodules", true)
+
+target("stdmodules")
     set_kind("binary")
     add_files("test/*.cpp")
     add_deps("mod")
+
+    set_policy("build.c++.clang.stdmodules", true)
diff --git a/tests/projects/c++/modules/stdmodules_multiple_targets/test.lua b/tests/projects/c++/modules/stdmodules_multiple_targets/test.lua
index 0657ead56..e77adc4ae 100644
--- a/tests/projects/c++/modules/stdmodules_multiple_targets/test.lua
+++ b/tests/projects/c++/modules/stdmodules_multiple_targets/test.lua
@@ -1 +1 @@
-inherit(".test_msvc")
+inherit(".test_stdmodules")
diff --git a/tests/projects/c++/modules/stdmodules_multiple_targets/xmake.lua b/tests/projects/c++/modules/stdmodules_multiple_targets/xmake.lua
index 859dddc7c..32bed613b 100644
--- a/tests/projects/c++/modules/stdmodules_multiple_targets/xmake.lua
+++ b/tests/projects/c++/modules/stdmodules_multiple_targets/xmake.lua
@@ -1,13 +1,14 @@
 add_rules("mode.debug", "mode.release")
-
-add_cxxflags("clang::-stdlib=libc++")
-
 set_languages("c++latest")
 
 target("mod")
     set_kind("static")
     add_files("src/*.cpp", "src/*.mpp")
 
+    set_policy("build.c++.clang.stdmodules", true)
+
 target("mod2")
     set_kind("static")
     add_files("src/*.cpp", "src/*.mpp")
+
+    set_policy("build.c++.clang.stdmodules", true)
diff --git a/tests/projects/c++/modules/stl_headerunit/xmake.lua b/tests/projects/c++/modules/stl_headerunit/xmake.lua
index e85378c46..55d55a5fd 100644
--- a/tests/projects/c++/modules/stl_headerunit/xmake.lua
+++ b/tests/projects/c++/modules/stl_headerunit/xmake.lua
@@ -1,4 +1,7 @@
+add_rules("mode.release", "mode.debug")
 set_languages("c++20")
+
 target("stl_headerunit")
     set_kind("binary")
     add_files("src/*.cpp", "src/*.mpp")
+
diff --git a/tests/projects/c++/modules/stl_headerunit_cpp_only/xmake.lua b/tests/projects/c++/modules/stl_headerunit_cpp_only/xmake.lua
index 101a95fe7..97a260e1e 100644
--- a/tests/projects/c++/modules/stl_headerunit_cpp_only/xmake.lua
+++ b/tests/projects/c++/modules/stl_headerunit_cpp_only/xmake.lua
@@ -1,76 +1,8 @@
-add_rules("mode.debug", "mode.release")
+add_rules("mode.release", "mode.debug")
+set_languages("c++20")
 
-target("test")
+target("stl_headerunit_cpp_only")
     set_kind("binary")
     add_files("src/*.cpp")
-    set_languages("c++20")
     set_policy("build.c++.modules", true)
---
--- If you want to known more usage about xmake, please see https://xmake.io
---
--- ## FAQ
---
--- You can enter the project directory firstly before building project.
---
---   $ cd projectdir
---
--- 1. How to build project?
---
---   $ xmake
---
--- 2. How to configure project?
---
---   $ xmake f -p [macosx|linux|iphoneos ..] -a [x86_64|i386|arm64 ..] -m [debug|release]
---
--- 3. Where is the build output directory?
---
---   The default output directory is `./build` and you can configure the output directory.
---
---   $ xmake f -o outputdir
---   $ xmake
---
--- 4. How to run and debug target after building project?
---
---   $ xmake run [targetname]
---   $ xmake run -d [targetname]
---
--- 5. How to install target to the system directory or other output directory?
---
---   $ xmake install
---   $ xmake install -o installdir
---
--- 6. Add some frequently-used compilation flags in xmake.lua
---
--- @code
---    -- add debug and release modes
---    add_rules("mode.debug", "mode.release")
---
---    -- add macro defination
---    add_defines("NDEBUG", "_GNU_SOURCE=1")
---
---    -- set warning all as error
---    set_warnings("all", "error")
---
---    -- set language: c99, c++11
---    set_languages("c99", "c++11")
---
---    -- set optimization: none, faster, fastest, smallest
---    set_optimize("fastest")
---
---    -- add include search directories
---    add_includedirs("/usr/include", "/usr/local/include")
---
---    -- add link libraries and search directories
---    add_links("tbox")
---    add_linkdirs("/usr/local/lib", "/usr/lib")
---
---    -- add system link libraries
---    add_syslinks("z", "pthread")
---
---    -- add compilation and link flags
---    add_cxflags("-stdnolib", "-fno-strict-aliasing")
---    add_ldflags("-L/usr/local/lib", "-lpthread", {force = true})
---
--- @endcode
---
 
diff --git a/tests/projects/c++/modules/submodules/xmake.lua b/tests/projects/c++/modules/submodules/xmake.lua
index 672034947..e84b63a9f 100644
--- a/tests/projects/c++/modules/submodules/xmake.lua
+++ b/tests/projects/c++/modules/submodules/xmake.lua
@@ -1,4 +1,6 @@
+add_rules("mode.release", "mode.debug")
 set_languages("c++20")
-target("math")
+
+target("submodule")
     set_kind("binary")
     add_files("src/*.cpp", "src/*.mpp")
diff --git a/tests/projects/c++/modules/submodules2/xmake.lua b/tests/projects/c++/modules/submodules2/xmake.lua
index 672034947..9dc2ee320 100644
--- a/tests/projects/c++/modules/submodules2/xmake.lua
+++ b/tests/projects/c++/modules/submodules2/xmake.lua
@@ -1,4 +1,6 @@
+add_rules("mode.release", "mode.debug")
 set_languages("c++20")
-target("math")
+
+target("submodules2")
     set_kind("binary")
     add_files("src/*.cpp", "src/*.mpp")
diff --git a/tests/projects/c++/modules/test_base.lua b/tests/projects/c++/modules/test_base.lua
index 4aee9f8e7..efef15520 100644
--- a/tests/projects/c++/modules/test_base.lua
+++ b/tests/projects/c++/modules/test_base.lua
@@ -16,7 +16,7 @@ function main(t)
         _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 then
+        if is_host("linux") and gcc and gcc.version and semver.compare(gcc.version, "11.0") >= 0 then
             os.exec("xmake f -c")
             _build()
         end
@@ -25,6 +25,9 @@ function main(t)
             os.exec("xmake clean -a")
             os.exec("xmake f --toolchain=clang -c")
             _build()
+            os.exec("xmake clean -a")
+            os.exec("xmake f --toolchain=clang --cxxflags=\"-stdlib=libc++\" -c")
+            _build()
         end
     end
 end
diff --git a/tests/projects/c++/modules/test_headerunits.lua b/tests/projects/c++/modules/test_headerunits.lua
index 78c999497..6a942e583 100644
--- a/tests/projects/c++/modules/test_headerunits.lua
+++ b/tests/projects/c++/modules/test_headerunits.lua
@@ -25,10 +25,17 @@ function main(t)
             _build()
         end
         local clang = find_tool("clang", {version = true})
-        if clang and clang.version and semver.compare(clang.version, "16.0") >= 0 then
-            os.exec("xmake clean -a")
-            os.exec("xmake f --toolchain=clang -c --yes")
-            _build()
+        if clang and clang.version then
+            if semver.compare(clang.version, "15.0") >= 0 then
+                os.exec("xmake clean -a")
+                os.exec("xmake f --toolchain=clang -c")
+                _build()
+            -- elseif semver.compare(clang.version, "15.0") >= 0 then
+            -- there is currently a bug on llvm git that prevent to build STL header units https://github.com/llvm/llvm-project/issues/58540
+            -- os.exec("xmake clean -a")
+            -- os.exec("xmake f --toolchain=clang --cxxflags=\"-stdlib=libc++\" -c")
+            -- _build()
+            end
         end
     end
 end
diff --git a/tests/projects/c++/modules/test_msvc.lua b/tests/projects/c++/modules/test_stdmodules.lua
index a436b5814..360a56cbc 100644
--- a/tests/projects/c++/modules/test_msvc.lua
+++ b/tests/projects/c++/modules/test_stdmodules.lua
@@ -24,5 +24,22 @@ function main(t)
                 end
             end
         end
+    elseif is_host("linux") then -- or is_host("macosx") then
+        -- gcc don't support std modules atm
+        -- local gcc = find_tool("gcc", {version = true})
+        -- if is_host("linux") and gcc and gcc.version and semver.compare(gcc.version, "11.0") >= 0 then
+            -- os.exec("xmake f -c")
+            -- _build()
+        -- end
+        local clang = find_tool("clang", {version = true})
+        if clang and clang.version and semver.compare(clang.version, "14.0") >= 0 then
+            -- clang don't support libstdc++ std modules atm
+            -- os.exec("xmake clean -a")
+            -- os.exec("xmake f --toolchain=clang -c")
+            -- _build()
+            os.exec("xmake clean -a")
+            os.exec("xmake f --toolchain=clang --cxxflags=\"-stdlib=libc++\" -c")
+            _build()
+        end
     end
 end
diff --git a/tests/projects/c++/modules/user_headerunit/xmake.lua b/tests/projects/c++/modules/user_headerunit/xmake.lua
index dae91d11f..e305044b5 100644
--- a/tests/projects/c++/modules/user_headerunit/xmake.lua
+++ b/tests/projects/c++/modules/user_headerunit/xmake.lua
@@ -1,4 +1,6 @@
+add_rules("mode.release", "mode.debug")
 set_languages("c++20")
+
 target("user_headerunit")
     set_kind("binary")
     add_headerfiles("src/*.hpp")
diff --git a/xmake/core/project/policy.lua b/xmake/core/project/policy.lua
index 8148a37e2..4c9f87cd1 100644
--- a/xmake/core/project/policy.lua
+++ b/xmake/core/project/policy.lua
@@ -53,6 +53,8 @@ function policy.policies()
             ["build.optimization.lto"]           = {description = "Enable LTO linker-time optimization for c/c++ building.", type = "boolean"},
             -- enable C++ modules for C++ building, even if no .mpp is involved in the compilation
             ["build.c++.modules"]                = {description = "Enable C++ modules for C++ building.", type = "boolean"},
+            -- enable clang std modulemap
+            ["build.c++.clang.stdmodules"]      = {description = "Enable clang std modulemap.", default = false, type = "boolean"},
             -- preprocessor configuration for ccache/distcc, we can disable linemarkers to speed up preprocess
             ["preprocessor.linemarkers"]         = {description = "Enable linemarkers for preprocessor.", default = true, type = "boolean"},
             -- preprocessor configuration for ccache/distcc, we can disable it to avoid cache object file with __DATE__, __TIME__
diff --git a/xmake/rules/c++/modules/modules_support/clang.lua b/xmake/rules/c++/modules/modules_support/clang.lua
index 0f159ae57..4d1f07747 100644
--- a/xmake/rules/c++/modules/modules_support/clang.lua
+++ b/xmake/rules/c++/modules/modules_support/clang.lua
@@ -65,16 +65,31 @@ function _get_modulemap_from_mapper(target, name)
     return common.localcache():get2(_mapper_cachekey(target), "modulemap" .. name) or nil
 end
 
+-- enable libc++
+function _enable_libcxx(target)
+    target:add("cxxflags", "-stdlib=libc++")
+    target:add("syslinks", "c++")
+end
+
 -- load module support for the current target
 function load(target)
-    local modulesflag = get_modulesflag(target)
+    local modulesflag, modulestsflag = get_modulesflag(target)
     local builtinmodulemapflag = get_builtinmodulemapflag(target)
     local implicitmodulesflag = get_implicitmodulesflag(target)
+    local noimplicitmodulemapsflag = get_noimplicitmodulemapsflag(target)
 
     -- add module flags
     target:add("cxxflags", modulesflag)
-    target:add("cxxflags", builtinmodulemapflag, {force = true})
-    target:add("cxxflags", implicitmodulesflag, {force = true})
+    if not modulesflag or target:is_plat("macosx") then
+        target:add("cxxflags", modulestsflag)
+    end
+
+    if target:policy("build.c++.clang.stdmodules") then
+       target:add("cxxflags", builtinmodulemapflag, {force = true})
+       target:add("cxxflags", implicitmodulesflag, {force = true})
+    else
+       target:add("cxxflags", noimplicitmodulemapsflag, {force = true})
+    end
 
     -- fix default visibility for functions and variables [-fvisibility] differs in PCH file vs. current file
     -- module.pcm cannot be loaded due to a configuration mismatch with the current compilation.
@@ -98,9 +113,10 @@ function load(target)
     -- on ubuntu:
     -- sudo apt install libc++-dev libc++abi-15-dev
     --
-    target:data_set("cxx.modules.use_libc++", table.contains(target:get("cxxflags"), "-stdlib=libc++", "clang::-stdlib=libc++"))
+    local flags = table.join(target:get("cxxflags"), get_config("cxxflags") or {})
+    target:data_set("cxx.modules.use_libc++", table.contains(flags, "-stdlib=libc++", "clang::-stdlib=libc++"))
     if target:data("cxx.modules.use_libc++") then
-        target:add("syslinks", "c++")
+        _enable_libcxx(target)
     end
 end
 
@@ -118,7 +134,7 @@ function _get_toolchain_includedirs_for_stlheaders(target, includedirs, clang)
     if target:data("cxx.modules.use_libc++") then
         table.insert(argv, 1, "-stdlib=libc++")
     end
-    local result = try {function () return os.iorunv(clang, {"-E", "-x", "c++", tmpfile}) end}
+    local result = try {function () return os.iorunv(clang, argv) end}
     if result then
         for _, line in ipairs(result:split("\n", {plain = true})) do
             line = line:trim()
@@ -169,7 +185,7 @@ function _build_modulefile(target, sourcefile, opt)
     local bmiflags
     if opt.provide then
         bmifile = opt.provide.bmifile
-        bmiflags = table.join("-x", "c++-module", "--precompile", compflags, common_args, requiresflags or {})
+        bmiflags = table.join("-x", "c++-module", "--precompile", compflags, common_args, requiresflags)
         vprint(compinst:compcmd(sourcefile, bmifile, {compflags = bmiflags, rawargs = true}))
     end
 
@@ -200,7 +216,7 @@ function toolchain_includedirs(target)
         local clang, toolname = target:tool("cxx")
         assert(toolname == "clang")
         _get_toolchain_includedirs_for_stlheaders(target, includedirs, clang)
-        local _, result = try {function () return os.iorunv(clang, {"-E", "-Wp,-v", "-xc", os.nuldev()}) end}
+        local _, result = try {function () return os.iorunv(clang, {"-E", "-stdlib=libc++", "-Wp,-v", "-xc", os.nuldev()}) end}
         if result then
             for _, line in ipairs(result:split("\n", {plain = true})) do
                 line = line:trim()
@@ -264,8 +280,39 @@ function generate_dependencies(target, sourcebatch, opt)
             end)
             changed = true
 
-            local dependinfo = io.readfile(jsonfile)
-            return {moduleinfo = dependinfo}
+            local rawdependinfo = io.readfile(jsonfile)
+            if rawdependinfo then
+                local dependinfo = json.decode(rawdependinfo)
+                if not target:data("cxx.modules.use_libc++") then
+                    local has_std_modules = false
+                    for _, r in ipairs(dependinfo.rules) do
+                        for _, required in ipairs(r.requires) do
+                            if required["logical-name"] == "std" or required["logical-name"] == "std.compat" then
+                                has_std_modules = true
+                                break
+                            end
+                        end
+
+                        if has_std_modules then
+                            break
+                        end
+                    end
+
+                    assert(not (has_std_modules and not target:policy("build.c++.clang.stdmodules")),
+                           [[On llvm <= 16 standard C++ modules are not supported ;
+                           they can be emulated through clang modules and supported only on libc++ ;
+                           please add -stdlib=libc++ cxx flag or disable strict mode]])
+
+                    if has_std_modules then
+                        target:data_set("cxx.modules.use_libc++", true)
+                        if target:data("cxx.modules.use_libc++") then
+                            _enable_libcxx(target)
+                        end
+                    end
+                end
+            end
+
+            return {moduleinfo = rawdependinfo}
         end, {dependfile = dependfile, files = {sourcefile}})
     end
     return changed
@@ -293,7 +340,7 @@ function generate_stl_headerunits_for_batchjobs(target, batchjobs, headerunits,
                     if not common.memcache():get2(headerunit.name, "building") then
                         common.memcache():set2(headerunit.name, "building", true)
                         progress.show((index * 100) / total, "${color.build.object}compiling.headerunit.$(mode) %s", headerunit.name)
-                        local args = {modulecachepathflag .. stlcachedir, "-c", "-o", bmifile, "-x", "c++-system-header", headerunit.name}
+                        local args = {modulecachepathflag .. stlcachedir, "-c", "-Wno-everything", "-o", bmifile, "-x", "c++-system-header", headerunit.name}
                         os.vrunv(compinst:program(), table.join(compinst:compflags({target = target}), args))
                     end
 
@@ -618,20 +665,20 @@ end
 
 function get_modulesflag(target)
     local modulesflag = _g.modulesflag
-    if modulesflag == nil then
+    local modulestsflag = _g.modulestsflag
+    if modulesflag == nil and modulestsflag == nil then
         local compinst = target:compiler("cxx")
         if compinst:has_flags("-fmodules", "cxxflags", {flagskey = "clang_modules"}) then
             modulesflag = "-fmodules"
         end
-        if not modulesflag then
-            if compinst:has_flags("-fmodules-ts", "cxxflags", {flagskey = "clang_modules_ts"}) then
-                modulesflag = "-fmodules-ts"
-            end
+        if compinst:has_flags("-fmodules-ts", "cxxflags", {flagskey = "clang_modules_ts"}) then
+            modulestsflag = "-fmodules-ts"
         end
-        assert(modulesflag, "compiler(clang): does not support c++ module!")
+        assert(modulesflag or modulestsflag, "compiler(clang): does not support c++ module!")
         _g.modulesflag = modulesflag or false
+        _g.modulestsflag = modulestsflag or false
     end
-    return modulesflag or nil
+    return modulesflag or nil, modulestsflag or nil
 end
 
 function get_builtinmodulemapflag(target)
@@ -664,6 +711,19 @@ function get_implicitmodulesflag(target)
     return implicitmodulesflag or nil
 end
 
+function get_implicitmodulemapsflag(target)
+    local implicitmodulemapsflag = _g.implicitmodulemapsflag
+    if implicitmodulemapsflag == nil then
+        local compinst = target:compiler("cxx")
+        if compinst:has_flags("-fimplicit-module-maps", "cxxflags", {flagskey = "clang_implicit_module_map"}) then
+            implicitmodulemapsflag = "-fimplicit-module-maps"
+        end
+        assert(implicitmodulemapsflag, "compiler(clang): does not support c++ module!")
+        _g.implicitmodulemapsflag = implicitmodulemapsflag or false
+    end
+    return implicitmodulemapsflag or nil
+end
+
 function get_noimplicitmodulemapsflag(target)
     local noimplicitmodulemapsflag = _g.noimplicitmodulemapsflag
     if noimplicitmodulemapsflag == nil then
@@ -720,8 +780,9 @@ function has_headerunitsupport(target)
     local support_headerunits = _g.support_headerunits
     if support_headerunits == nil then
         local compinst = target:compiler("cxx")
-        if compinst:has_flags(get_modulesflag(target) .. " -std=c++20 -x c++-user-header", "cxxflags", {flagskey = "clang_user_header_unit_support", tryrun = true}) and
-           compinst:has_flags(get_modulesflag(target) .. " -std=c++20 -x c++-system-header", "cxxflags", {flagskey = "clang_system_header_unit_support", tryrun = true}) then
+        local modulesflag, modulestsflag = get_modulesflag(target)
+        if compinst:has_flags(modulesflag or moduletsflag .. " -std=c++20 -x c++-user-header", "cxxflags", {flagskey = "clang_user_header_unit_support", tryrun = true}) and
+           compinst:has_flags(modulesflag or moduletsflag .. " -std=c++20 -x c++-system-header", "cxxflags", {flagskey = "clang_system_header_unit_support", tryrun = true}) then
             support_headerunits = true
         end
         _g.support_headerunits = support_headerunits or false
@@ -745,7 +806,7 @@ function get_requiresflags(target, requires)
                 already_mapped_modules[name] = true
                 table.insert(flags, modulemap_.flag)
                 if modulemap_.deps then
-                    table.shallow_join2(flags, modulemap_.deps)
+                    table.join2(flags, modulemap_.deps)
                 end
                 goto continue
             end
@@ -757,7 +818,7 @@ function get_requiresflags(target, requires)
             already_mapped_modules[name] = true
             table.insert(flags, modulemap.flag)
             if modulemap.deps then
-                table.shallow_join2(flags, modulemap.deps)
+                table.join2(flags, modulemap.deps)
             end
             goto continue
         end