add "Fast" option to LinkTimeOptimization API which enables LTCG:incremental for vs2010, and behaves as "On" for other toolsets

Author: withmorten

modules/gmakelegacy/tests/cpp/test_clang.lua

@@ -78,3 +78,20 @@ ifeq ($(config),debug)
 		]]
 	end
 
+	function suite.usesCorrectCompilersAndFastLinkTimeOptimizationViaAPI()
+		linktimeoptimization "Fast"
+		make.cppConfigs(prj)
+		test.capture [[
+ifeq ($(config),debug)
+  ifeq ($(origin CC), default)
+    CC = clang
+  endif
+  ifeq ($(origin CXX), default)
+    CXX = clang++
+  endif
+  ifeq ($(origin AR), default)
+    AR = llvm-ar
+  endif
+		]]
+	end
+

modules/vstudio/tests/linux/test_linux_files.lua

@@ -42,6 +42,22 @@ local vc2010 = p.vstudio.vc2010
 		]]
 	end
 
+--
+-- Test fast link time optimization being equivalent to on. 
+--
+
+	function suite.linkTimeOptimization_Fast()
+		linktimeoptimization('fast')
+		prepareConfigProperties()
+		test.capture [[
+<PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x86'" Label="Configuration">
+	<ConfigurationType>Application</ConfigurationType>
+	<PlatformToolset>v142</PlatformToolset>
+	<LinkTimeOptimization>true</LinkTimeOptimization>
+</PropertyGroup>
+		]]
+	end
+
 --
 -- Test multiprocessor compilation.
 --

modules/vstudio/tests/vc200x/test_compiler_block.lua

@@ -632,6 +632,18 @@
 
 	end
 
+	function suite.flags_onLinkTimeOptimizationFast()
+		linktimeoptimization "Fast"
+		prepare()
+		test.capture [[
+<Tool
+	Name="VCCLCompilerTool"
+	Optimization="0"
+	WholeProgramOptimization="true"
+		]]
+
+	end
+
 
 --
 -- Check the optimization flags.

modules/vstudio/tests/vc2010/test_config_props.lua

@@ -364,6 +364,19 @@
 		]]
 	end
 
+	function suite.useOfLinkTimeOptimizationViaAPI_Fast()
+		linktimeoptimization "Fast"
+		prepare()
+		test.capture [[
+<PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+	<ConfigurationType>Application</ConfigurationType>
+	<UseDebugLibraries>false</UseDebugLibraries>
+	<CharacterSet>Unicode</CharacterSet>
+	<PlatformToolset>v100</PlatformToolset>
+	<WholeProgramOptimization>true</WholeProgramOptimization>
+		]]
+	end
+
 
 --
 -- Check the WindowsSDKDesktopARMSupport element

modules/vstudio/vs200x_vcproj.lua

@@ -1614,7 +1614,7 @@
 
 
 	function m.wholeProgramOptimization(cfg)
-		if cfg.linktimeoptimization == "On" then
+		if cfg.linktimeoptimization == "On" or cfg.linktimeoptimization == "Fast" then
 			p.x('WholeProgramOptimization="true"')
 		elseif cfg.linktimeoptimization == "Off" then
 			p.x('WholeProgramOptimization="false"')

modules/vstudio/vs2010_vcxproj.lua

@@ -2298,7 +2298,7 @@
 
 
 	function m.wholeProgramOptimization(cfg)
-		if cfg.linktimeoptimization == "On" then
+		if cfg.linktimeoptimization == "On" or cfg.linktimeoptimization == "Fast" then
 			m.element("WholeProgramOptimization", nil, "true")
 		elseif cfg.linktimeoptimization == "Off" then
 			m.element("WholeProgramOptimization", nil, "false")
@@ -3080,6 +3080,8 @@
 	function m.linkTimeCodeGeneration(cfg)
 		if cfg.linktimeoptimization == "On" then
 			m.element("LinkTimeCodeGeneration", nil, "UseLinkTimeCodeGeneration")
+		elseif cfg.linktimeoptimization == "Fast" then
+			m.element("LinkTimeCodeGeneration", nil, "UseFastLinkTimeCodeGeneration")
 		end
 	end
 
@@ -4016,7 +4018,7 @@
 	end
 
 	function m.linuxWholeProgramOptimization(cfg)
-		if cfg.linktimeoptimization == "On" then
+		if cfg.linktimeoptimization == "On" or cfg.linktimeoptimization == "Fast" then
 			m.element("LinkTimeOptimization", nil, "true")
 		elseif cfg.linktimeoptimization == "Off" then
 			m.element("LinkTimeOptimization", nil, "false")
@@ -4032,7 +4034,7 @@
 	end
 
 	function m.linuxLinkTimeCodeGeneration(cfg)
-		if cfg.linktimeoptimization == "On" then
+		if cfg.linktimeoptimization == "On" or cfg.linktimeoptimization == "Fast" then
 			m.element("LinkTimeOptimization", nil, "true")
 		end
 	end

src/_premake_init.lua

@@ -1129,6 +1129,7 @@
 		allowed = {
 			"Default",
 			"On",
+			"Fast",
 			"Off"
 		}
 	}

src/base/config.lua

@@ -155,7 +155,8 @@
 		if cfg.kind == "StaticLib"
 				or config.isOptimizedBuild(cfg)
 				or cfg.flags.NoIncrementalLink
-				or cfg.linktimeoptimization == "On" then
+				or cfg.linktimeoptimization == "On"
+				or cfg.linktimeoptimization == "Fast" then
 			return false
 		end
 		return true

src/tools/clang.lua

@@ -349,7 +349,7 @@
 	clang.tools = {
 		cc = "clang",
 		cxx = "clang++",
-		ar = function(cfg) return iif(cfg.linktimeoptimization == "On", "llvm-ar", "ar") end,
+		ar = function(cfg) return iif(cfg.linktimeoptimization == "On" or cfg.linktimeoptimization == "Fast", "llvm-ar", "ar") end,
 		rc = "windres"
 	}
 

src/tools/gcc.lua

@@ -71,6 +71,7 @@
 		},
 		linktimeoptimization = {
 			On = "-flto",
+			Fast = "-flto",
 		},
 		strictaliasing = {
 			Off = "-fno-strict-aliasing",