Add extra flags to CMakeToolchain

conan/tools/cmake/toolchain/blocks.py

@@ -565,10 +565,10 @@ class ExtraFlagsBlock(Block):
 
     def context(self):
         # Now, it's time to get all the flags defined by the user
-        cxxflags = self._conanfile.conf.get("tools.build:cxxflags", default=[], check_type=list)
-        cflags = self._conanfile.conf.get("tools.build:cflags", default=[], check_type=list)
-        sharedlinkflags = self._conanfile.conf.get("tools.build:sharedlinkflags", default=[], check_type=list)
-        exelinkflags = self._conanfile.conf.get("tools.build:exelinkflags", default=[], check_type=list)
+        cxxflags = self._toolchain.extra_cxxflags + self._conanfile.conf.get("tools.build:cxxflags", default=[], check_type=list)
+        cflags = self._toolchain.extra_cflags + self._conanfile.conf.get("tools.build:cflags", default=[], check_type=list)
+        sharedlinkflags = self._toolchain.extra_sharedlinkflags + self._conanfile.conf.get("tools.build:sharedlinkflags", default=[], check_type=list)
+        exelinkflags = self._toolchain.extra_exelinkflags + self._conanfile.conf.get("tools.build:exelinkflags", default=[], check_type=list)
         defines = self._conanfile.conf.get("tools.build:defines", default=[], check_type=list)
 
         # See https://github.com/conan-io/conan/issues/13374

conan/tools/cmake/toolchain/toolchain.py

@@ -125,6 +125,11 @@ def __init__(self, conanfile, generator=None):
         self.cache_variables = {}
         self.preprocessor_definitions = Variables()
 
+        self.extra_cxxflags = []
+        self.extra_cflags = []
+        self.extra_sharedlinkflags = []
+        self.extra_exelinkflags = []
+
         self.blocks = ToolchainBlocks(self._conanfile, self,
                                       [("user_toolchain", UserToolchain),
                                        ("generic_system", GenericSystemBlock),

conans/test/integration/toolchains/cmake/test_cmaketoolchain.py

@@ -1140,3 +1140,39 @@ def layout(self):
     presets = load(os.path.join(build_folder,
                                 "build/windows-shared/Debug/generators/CMakePresets.json"))
     assert "conan-windows-shared-debug" in presets
+
+
+def test_extra_flags():
+    client = TestClient()
+    conanfile = textwrap.dedent("""
+        from conan import ConanFile
+        from conan.tools.cmake import CMakeToolchain
+
+        class Conan(ConanFile):
+            name = "pkg"
+            version = "0.1"
+            settings = "os", "arch", "build_type"
+            def generate(self):
+                tc = CMakeToolchain(self)
+                tc.extra_cxxflags = ["extra_cxxflags"]
+                tc.extra_cflags = ["extra_cflags"]
+                tc.extra_sharedlinkflags = ["extra_sharedlinkflags"]
+                tc.extra_exelinkflags = ["extra_exelinkflags"]
+                tc.generate()
+        """)
+    profile = textwrap.dedent("""
+        include(default)
+        [conf]
+        tools.build:cxxflags+=['cxxflags']
+        tools.build:cflags+=['cflags']
+        tools.build:sharedlinkflags+=['sharedlinkflags']
+        tools.build:exelinkflags+=['exelinkflags']
+        """)
+    client.save({"conanfile.py": conanfile, "profile": profile})
+    client.run('install . -pr=./profile')
+    toolchain = client.load("conan_toolchain.cmake")
+
+    assert 'string(APPEND CONAN_CXX_FLAGS " extra_cxxflags cxxflags")' in toolchain
+    assert 'string(APPEND CONAN_C_FLAGS " extra_cflags cflags")' in toolchain
+    assert 'string(APPEND CONAN_SHARED_LINKER_FLAGS " extra_sharedlinkflags sharedlinkflags")' in toolchain
+    assert 'string(APPEND CONAN_EXE_LINKER_FLAGS " extra_exelinkflags exelinkflags")' in toolchain