Improved handling of precompiled headers across toolsets

1 files changed, 58 insertions, 35 deletions

diff --git a/src/actions/make/make_cpp.lua b/src/actions/make/make_cpp.lua
index c00b5e0..0efd321 100644
--- a/src/actions/make/make_cpp.lua
+++ b/src/actions/make/make_cpp.lua
@@ -1,7 +1,7 @@
 --
 -- make_cpp.lua
 -- Generate a C/C++ project makefile.
--- Copyright (c) 2002-2011 Jason Perkins and the Premake project
+-- Copyright (c) 2002-2013 Jason Perkins and the Premake project
 --
 
 	premake.make.cpp = { }
@@ -109,19 +109,8 @@
 		-- precompiler header rule
 		cpp.pchrules(prj)
 
-		-- per-file rules
-		for _, file in ipairs(prj.files) do
-			if path.iscppfile(file) then
-				_p('$(OBJDIR)/%s.o: %s', _MAKE.esc(path.getbasename(file)), _MAKE.esc(file))
-				_p('\t@echo $(notdir $<)')
-				cpp.buildcommand(path.iscfile(file), "o")
-			elseif (path.getextension(file) == ".rc") then
-				_p('$(OBJDIR)/%s.res: %s', _MAKE.esc(path.getbasename(file)), _MAKE.esc(file))
-				_p('\t@echo $(notdir $<)')
-				_p('\t$(SILENT) $(RESCOMP) $< -O coff -o "$@" $(ALL_RESFLAGS)')
-			end
-		end
-		_p('')
+		-- per-file build rules
+		cpp.fileRules(prj)
 
 		-- include the dependencies, built by GCC (with the -MMD flag)
 		_p('-include $(OBJECTS:%%.o=%%.d)')
@@ -182,15 +171,15 @@
 		_p('  DEFINES   +=%s', make.list(cc.getdefines(cfg.defines)))
 		_p('  INCLUDES  +=%s', make.list(cc.getincludedirs(cfg.includedirs)))
 
+		-- set up precompiled headers
+		cpp.pchconfig(cfg)
+
 		-- CPPFLAGS, CFLAGS, CXXFLAGS, and RESFLAGS
 		cpp.flags(cfg, cc)
 
 		-- write out libraries, linker flags, and the link command
 		cpp.linker(cfg, cc)
 
-		-- set up precompiled headers
-		cpp.pchconfig(cfg)
-
 		_p('  define PREBUILDCMDS')
 		if #cfg.prebuildcommands > 0 then
 			_p('\t@echo Running pre-build commands')
@@ -243,7 +232,13 @@
 --
 
 	function cpp.flags(cfg, cc)
-		_p('  ALL_CPPFLAGS  += $(CPPFLAGS) %s $(DEFINES) $(INCLUDES)', table.concat(cc.getcppflags(cfg), " "))
+
+		if cfg.pchheader and not cfg.flags.NoPCH then
+			_p('  FORCE_INCLUDE += -include $(OBJDIR)/$(notdir $(PCH))')
+		end
+
+		_p('  ALL_CPPFLAGS  += $(CPPFLAGS) %s $(DEFINES) $(INCLUDES) $(FORCE_INCLUDE)', table.concat(cc.getcppflags(cfg), " "))
+
 		_p('  ALL_CFLAGS    += $(CFLAGS) $(ALL_CPPFLAGS) $(ARCH)%s', make.list(table.join(cc.getcflags(cfg), cfg.buildoptions)))
 		_p('  ALL_CXXFLAGS  += $(CXXFLAGS) $(ALL_CFLAGS)%s', make.list(cc.getcxxflags(cfg)))
 
@@ -286,35 +281,47 @@
 --
 
 	function cpp.pchconfig(cfg)
-		-- GCC needs the full path to the PCH, while Visual Studio needs
-		-- only the name (or rather, the name as specified in the #include
-		-- statement). Try to locate the PCH in the project.
-		local pchheader = cfg.pchheader
+
+		-- If there is no header, or if PCH has been disabled, I can early out
+
+		if not cfg.pchheader or cfg.flags.NoPCH then
+			return
+		end
+
+		-- Visual Studio requires the PCH header to be specified in the same way
+		-- it appears in the #include statements used in the source code; the PCH
+		-- source actual handles the compilation of the header. GCC compiles the
+		-- header file directly, and needs the file's actual file system path in
+		-- order to locate it.
+
+		-- To maximize the compatibility between the two approaches, see if I can
+		-- locate the specified PCH header on one of the include file search paths
+		-- and, if so, adjust the path automatically so the user doesn't have
+		-- add a conditional configuration to the project script.
+
+		local pch = cfg.pchheader
 		for _, incdir in ipairs(cfg.includedirs) do
-			local testname = path.join(incdir, cfg.pchheader)
+			local testname = path.join(incdir, pch)
 			if os.isfile(testname) then
-				pchheader = testname
+				pch = testname
 				break
 			end
 		end
 
-		if not cfg.flags.NoPCH and cfg.pchheader then
-			_p('  PCH        = %s', _MAKE.esc(path.getrelative(cfg.location, cfg.pchheader)))
-			_p('  GCH        = $(OBJDIR)/%s.gch', _MAKE.esc(path.getname(cfg.pchheader)))
-			_p('  ALL_CPPFLAGS  += -I$(OBJDIR) -include $(OBJDIR)/%s', _MAKE.esc(path.getname(cfg.pchheader)))
-		end
+		_p('  PCH        = %s', _MAKE.esc(path.getrelative(cfg.location, cfg.pchheader)))
+		_p('  GCH        = $(OBJDIR)/$(notdir $(PCH)).gch', _MAKE.esc(path.getname(cfg.pchheader)))
+
 	end
 
+
 	function cpp.pchrules(prj)
 		_p('ifneq (,$(PCH))')
 		_p('$(GCH): $(PCH)')
 		_p('\t@echo $(notdir $<)')
-		_p('ifeq (posix,$(SHELLTYPE))')
-		_p('\t-$(SILENT) cp $< $(OBJDIR)')
-		_p('else')
-		_p('\t$(SILENT) xcopy /D /Y /Q "$(subst /,\\,$<)" "$(subst /,\\,$(OBJDIR))" 1>nul')
-		_p('endif')
-		cpp.buildcommand(prj.language == "C", "gch")
+
+		local cmd = iif(prj.language == "C", "$(CC) -x c-header", "$(CXX) -x c++-header")
+		_p('\t$(SILENT) %s $(CPPFLAGS) -MMD -MP $(DEFINES) $(INCLUDES) -o "$@" -MF "$(@:%%.gch=%%.d)" -c "$<"', cmd)
+
 		_p('endif')
 		_p('')
 	end
@@ -324,6 +331,22 @@
 -- Build command for a single file.
 --
 
+	function cpp.fileRules(prj)
+		for _, file in ipairs(prj.files or {}) do
+			if path.iscppfile(file) then
+				_p('$(OBJDIR)/%s.o: %s', _MAKE.esc(path.getbasename(file)), _MAKE.esc(file))
+				_p('\t@echo $(notdir $<)')
+				cpp.buildcommand(path.iscfile(file), "o")
+				_p('')
+			elseif (path.getextension(file) == ".rc") then
+				_p('$(OBJDIR)/%s.res: %s', _MAKE.esc(path.getbasename(file)), _MAKE.esc(file))
+				_p('\t@echo $(notdir $<)')
+				_p('\t$(SILENT) $(RESCOMP) $< -O coff -o "$@" $(ALL_RESFLAGS)')
+				_p('')
+			end
+		end
+	end
+
 	function cpp.buildcommand(iscfile, objext)
 		local flags = iif(iscfile, '$(CC) $(ALL_CFLAGS)', '$(CXX) $(ALL_CXXFLAGS)')
 		_p('\t$(SILENT) %s -o "$@" -MF $(@:%%.%s=%%.d) -c "$<"', flags, objext)