New API strictaliasing() with GCC support

src/_premake_init.lua

@@ -630,6 +630,18 @@
 		tokens = true,
 	}
 
+	api.register {
+		name = "strictaliasing",
+		scope = "config",
+		kind = "string",
+		allowed = {
+			"Off",
+			"Level1",
+			"Level2",
+			"Level3",
+		}
+	}
+
 	api.register {
 		name = "system",
 		scope = "config",

src/tools/gcc.lua

@@ -51,6 +51,12 @@
 				if cfg.system ~= premake.WINDOWS then return "-fPIC" end
 			end,
 		},
+		strictaliasing = {
+			Off = "-fno-strict-aliasing",
+			Level1 = { "-fstrict-aliasing", "-Wstrict-aliasing=1" },
+			Level2 = { "-fstrict-aliasing", "-Wstrict-aliasing=2" },
+			Level3 = { "-fstrict-aliasing", "-Wstrict-aliasing=3" },
+		},
 		optimize = {
 			Off = "-O0",
 			On = "-O2",

tests/tools/test_gcc.lua

@@ -402,3 +402,32 @@
 		test.isequal({ '-I"$(IntDir)/includes"' }, gcc.getincludedirs(cfg, cfg.includedirs))
 	end
 
+
+
+--
+-- Check handling of strict aliasing flags.
+--
+
+	function suite.cflags_onNoStrictAliasing()
+		strictaliasing "Off"
+		prepare()
+		test.contains("-fno-strict-aliasing", gcc.getcflags(cfg))
+	end
+
+	function suite.cflags_onLevel1Aliasing()
+		strictaliasing "Level1"
+		prepare()
+		test.contains({ "-fstrict-aliasing", "-Wstrict-aliasing=1" }, gcc.getcflags(cfg))
+	end
+
+	function suite.cflags_onLevel2Aliasing()
+		strictaliasing "Level2"
+		prepare()
+		test.contains({ "-fstrict-aliasing", "-Wstrict-aliasing=2" }, gcc.getcflags(cfg))
+	end
+
+	function suite.cflags_onLevel3Aliasing()
+		strictaliasing "Level3"
+		prepare()
+		test.contains({ "-fstrict-aliasing", "-Wstrict-aliasing=3" }, gcc.getcflags(cfg))
+	end