improve c++/objc++ rules

1 files changed, 92 insertions, 0 deletions

diff --git a/xmake/rules/c++/config/optimization.lua b/xmake/rules/c++/config/optimization.lua
new file mode 100644
index 000000000..44b6ce755
--- /dev/null
+++ b/xmake/rules/c++/config/optimization.lua
@@ -0,0 +1,92 @@
+--!A cross-platform build utility based on Lua
+--
+-- Licensed under the Apache License, Version 2.0 (the "License");
+-- you may not use this file except in compliance with the License.
+-- You may obtain a copy of the License at
+--
+--     http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+--
+-- Copyright (C) 2015-present, Xmake Open Source Community.
+--
+-- @author      ruki
+-- @file        optimization.lua
+--
+
+-- imports
+import("core.tool.compiler")
+import("core.project.project")
+
+-- add lto optimization
+function main(target, sourcekind)
+    if not (target:policy("build.optimization.lto") or project.policy("build.optimization.lto")) then
+        return
+    end
+
+    -- add cflags
+    local _, cc = target:tool(sourcekind)
+    local cflag = sourcekind == "cxx" and "cxxflags" or "cflags"
+    if cc == "cl" then
+        target:add(cflag, "-GL")
+    elseif cc == "clang" or cc == "clangxx" or cc == "clang_cl" then
+        target:add(cflag, "-flto=thin")
+    elseif cc == "gcc" or cc == "gxx" then
+        target:add(cflag, "-flto")
+    end
+
+    -- add ldflags and shflags
+    local program, ld = target:tool("ld")
+    if ld == "link" then
+        target:add("ldflags", "-LTCG")
+        target:add("shflags", "-LTCG")
+    elseif ld == "clang" or ld == "clangxx" then
+        target:add("ldflags", "-flto=thin")
+        target:add("shflags", "-flto=thin")
+
+        -- On Darwin, when using -flto along with -g and compiling and linking in separate steps,
+        -- you also need to pass -Wl,-object_path_lto,<lto-filename>.o at the linking step to instruct
+        -- the ld64 linker not to delete the temporary object file generated during Link Time Optimization
+        -- (this flag is automatically passed to the linker by Clang if compilation and linking are done in a single step).
+        --
+        -- This allows debugging the executable as well as generating the .dSYM bundle using dsymutil(1).
+        --
+        -- @see https://github.com/xmake-io/xmake/issues/7029
+        -- https://clang.llvm.org/docs/CommandGuide/clang.html
+        if target:is_plat("macosx", "iphoneos", "watchos") then
+            local lto_objectfile = target:objectfile(target:targetfile() .. ".lto")
+            target:add("ldflags", "-Wl,-object_path_lto," .. lto_objectfile)
+            target:add("shflags", "-Wl,-object_path_lto," .. lto_objectfile)
+        end
+    elseif ld == "gcc" or ld == "gxx" then
+        target:add("ldflags", "-flto")
+        target:add("shflags", "-flto")
+
+        -- to use the link-time optimizer, -flto and optimization options should be specified at compile time and during the final link.
+        -- @see https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html
+        local optimize = target:get("optimize")
+        if optimize then
+            local optimize_flags = compiler.map_flags(sourcekind == "cc" and "c" or "cxx", "optimize", optimize)
+            target:add("ldflags", optimize_flags)
+            target:add("shflags", optimize_flags)
+        end
+    end
+
+    local program, ar = target:tool("ar")
+    if cc == "clang_cl" then
+        if ld == "link" then
+            wprint([[Unsupported toolset(%s) for lto, please use `set_toolset("ld", "lld-link")`]], ld)
+            target:set("toolset", "ld", "lld-link")
+            target:set("toolset", "sh", "lld-link")
+        end
+        if ar ~= "llvm-ar" and ar ~= "llvm_ar" then
+            wprint([[Unsupported toolset(%s) for lto, please use `set_toolset("ar", "llvm-ar")`]], ar)
+            target:set("toolset", "ar", "llvm-ar")
+        end
+    end
+end
+