Handle warning flags better

Make --enable-werror work properly on msvc, handle extra warnings
flags for msvc in configure.ac instead of hardcoding into
make/msvc.mk, separate warnings flags into WFLAGS in autoconf.mk to
avoid duplication and to make it easier to override.

ChangeLog

@@ -25,6 +25,15 @@
 
 2013-01-24  Jay Berkenbilt  <ejb@ql.org>
 
+	* Make --enable-werror work for MSVC, and generally handle warning
+	options better for that compiler.  Warning flags for that compiler
+	were previous hard-coded into the build with /WX enabled
+	unconditionally.
+
+	* Split warning flags into WFLAGS in autoconf.mk to make them
+	easier to override.  Before they were repeated in CFLAGS and
+	CXXFLAGS and were commingled with other compiler flags.
+
 	* qpdf --check now does syntactic checks all pages' content
 	streams as well as checking overall document structure.  Semantic
 	errors are still not checked, and there are no plans to add

autoconf.mk.in

@@ -12,12 +12,13 @@ docdir=@docdir@
 htmldir=@htmldir@
 pdfdir=@pdfdir
 CC=@CC@
-CFLAGS=@CFLAGS@
+WFLAGS=@WFLAGS@
+CFLAGS=@CFLAGS@ $(WFLAGS)
 LDFLAGS=@LDFLAGS@
 LIBS=@LIBS@
 CPPFLAGS=@CPPFLAGS@
 CXX=@CXX@
-CXXFLAGS=@CXXFLAGS@
+CXXFLAGS=@CXXFLAGS@ $(WFLAGS)
 AR=@AR@
 RANLIB=@RANLIB@
 DLLTOOL=@DLLTOOL@

config-mingw32

@@ -1,5 +1,5 @@
 #!/bin/sh
-./configure --disable-test-compare-images --enable-external-libs --with-windows-wordsize=32 --with-buildrules=mingw
+./configure --disable-test-compare-images --enable-external-libs --enable-werror --with-windows-wordsize=32 --with-buildrules=mingw
 # As of autoconf 2.69 and gcc 4.6, autoconf's configure fails to
 # recognize that defining _FILE_OFFSET_BITS works with mingw32.
 # Append to qpdf-config.h rather than passing CPPFLAGS on the

config-mingw64

@@ -1,5 +1,5 @@
 #!/bin/sh
-./configure --disable-test-compare-images --enable-external-libs --with-windows-wordsize=64 --with-buildrules=mingw \
+./configure --disable-test-compare-images --enable-external-libs --enable-werror --with-windows-wordsize=64 --with-buildrules=mingw \
     CC=x86_64-w64-mingw32-gcc \
     CXX=x86_64-w64-mingw32-g++ \
     LD=x86_64-w64-mingw32-ld \

config-msvc

@@ -8,4 +8,4 @@ objdump=
 if test "$wordsize" = "64"; then
     objdump=OBJDUMP=x86_64-w64-mingw32-objdump
 fi
-CC=cl CXX="cl -TP -GR" ./configure --disable-test-compare-images --enable-external-libs --with-windows-wordsize=$wordsize --with-buildrules=msvc $objdump
+CC=cl CXX="cl -TP -GR" ./configure --disable-test-compare-images --enable-external-libs --enable-werror --with-windows-wordsize=$wordsize --with-buildrules=msvc $objdump

configure.ac

@@ -175,39 +175,48 @@ AC_ARG_WITH(buildrules,
    [BUILDRULES=libtool])
 AC_MSG_RESULT($BUILDRULES)
 
-if test "$BUILDRULES" != "msvc"; then
+AC_SUBST(WFLAGS)
-   qpdf_USE_WALL=0
+qpdf_USE_EXTRA_WARNINGS=0
-   AC_MSG_CHECKING(for whether $CC supports -Wall)
+if test "$BUILDRULES" = "msvc"; then
-   oCFLAGS=$CFLAGS
+   dnl /w14267 makes warning 4267 a level 1 warning.  This warning reports
-   CFLAGS="$CFLAGS -Wall"
+   dnl potential issues between size_t, off_t, and non-compatible integer
-   AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[int a = 1; int b = a; a = b;]])],
+   dnl types.
-                     [qpdf_USE_WALL=1],[qpdf_USE_WALL=0])
+   try_flags="/w14267"
-   if test "$qpdf_USE_WALL" = "1"; then
+else
-      AC_MSG_RESULT(yes)
+   try_flags="-Wall"
-      CXXFLAGS="$CXXFLAGS -Wall"
+fi
-   else
+AC_MSG_CHECKING(for whether $CC supports $try_flags)
-      AC_MSG_RESULT(no)
+oCFLAGS=$CFLAGS
-      CFLAGS=$oCFLAGS
+CFLAGS="$CFLAGS $try_flags"
-   fi
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[int a = 1; int b = a; a = b;]])],
+                  [qpdf_USE_EXTRA_WARNINGS=1],[qpdf_USE_EXTRA_WARNINGS=0])
+CFLAGS=$oCFLAGS
+if test "$qpdf_USE_EXTRA_WARNINGS" = "1"; then
+   AC_MSG_RESULT(yes)
+   WFLAGS="$try_flags"
+else
+   AC_MSG_RESULT(no)
 fi
 
-if test "$BUILDRULES" != "msvc"; then
+if test "$BUILDRULES" = "msvc"; then
-   AC_MSG_CHECKING(for whether to use -Werror)
+   try_flags="/WX"
-   AC_ARG_ENABLE(werror,
+else
-      AS_HELP_STRING([--enable-werror],
+   try_flags="-Werror"
-		     [whether to use werror (default is no)]),
+fi
-      [if test "$enableval" = "yes"; then
+AC_MSG_CHECKING(for whether to use $try_flags)
-	 qpdf_USE_WERROR=1;
+AC_ARG_ENABLE(werror,
-       else
+   AS_HELP_STRING([--enable-werror],
-	 qpdf_USE_WERROR=0;
+                  [whether to treat warnings as errors (default is no)]),
-       fi], [qpdf_USE_WERROR=0])
+   [if test "$enableval" = "yes"; then
-   if test "$qpdf_USE_WERROR" = "1"; then
+      qpdf_USE_WERROR=1;
-      AC_MSG_RESULT(yes)
+    else
-      CFLAGS="$CFLAGS -Werror"
+      qpdf_USE_WERROR=0;
-      CXXFLAGS="$CXXFLAGS -Werror"
+    fi], [qpdf_USE_WERROR=0])
-   else
+if test "$qpdf_USE_WERROR" = "1"; then
-      AC_MSG_RESULT(no)
+   AC_MSG_RESULT(yes)
-   fi
+   WFLAGS="$WFLAGS $try_flags"
+else
+   AC_MSG_RESULT(no)
 fi
 
 AC_SUBST(QPDF_SKIP_TEST_COMPARE_IMAGES)

make/msvc.mk

@@ -19,16 +19,6 @@ endef
 CFLAGS := $(filter-out -g,$(CFLAGS))
 CXXFLAGS := $(filter-out -g,$(CXXFLAGS))
 
-# /WX makes all warnings errors.
-CFLAGS += /WX
-CXXFLAGS += /WX
-
-# /w14267 makes warning 4267 a level 1 warning.  This warning reports
-# potential issues between size_t, off_t, and non-compatible integer
-# types.
-CFLAGS += /w14267
-CXXFLAGS += /w14267
-
 clean::
 	$(RM) *.pdb