Allow to use libgcc instead of libtcc1

This patch adds a switch --with-libgcc to configure.
When passed it prevents libtcc1.a from being built and links to
/lib/libgcc_s.so.1 instead of PREFIX/lib/tcc/libtcc1.a.

It will work on ARM when using libgcc from GCC >= 4.2.0.
Prior versions don't have the __floatun[sd]i[sdx]f functions.

It won't work on i386 because of two missing symbols emitted when
floats are cast to integers, but users can provide those symbols
(global short constants) in their code if needed.

  Daniel

3 files changed, 28 insertions, 4 deletions

diff --git a/Makefile b/Makefile
index 3ccebe3..1e6adad 100644
--- a/Makefile
+++ b/Makefile
@@ -51,11 +51,17 @@ PROGS+=c67-tcc$(EXESUF) i386-win32-tcc$(EXESUF)
 endif
 endif
 
+ifdef CONFIG_USE_LIBGCC
+LIBTCC1=
+else
+LIBTCC1=libtcc1.a
+endif
+
 # run local version of tcc with local libraries and includes
 TCC=./tcc -B. -I.
 
 all: $(PROGS) \
-     libtcc1.a $(BCHECK_O) tcc-doc.html tcc.1 libtcc.a \
+     $(LIBTCC1) $(BCHECK_O) tcc-doc.html tcc.1 libtcc.a \
      libtcc_test$(EXESUF)
 
 Makefile: config.mak
@@ -214,7 +220,7 @@ bcheck.o: bcheck.c
 
 install: tcc_install libinstall
 
-tcc_install: $(PROGS) tcc.1 libtcc1.a $(BCHECK_O) tcc-doc.html
+tcc_install: $(PROGS) tcc.1 $(LIBTCC1) $(BCHECK_O) tcc-doc.html
 	mkdir -p "$(DESTDIR)$(bindir)"
 	$(INSTALL) -s -m755 $(PROGS) "$(DESTDIR)$(bindir)"
 ifndef CONFIG_WIN32
@@ -225,11 +231,14 @@ endif
 	mkdir -p "$(DESTDIR)$(tccdir)/include"
 ifdef CONFIG_WIN32
 	mkdir -p "$(DESTDIR)$(tccdir)/lib"
-	$(INSTALL) -m644 libtcc1.a win32/lib/*.def "$(DESTDIR)$(tccdir)/lib"
+	$(INSTALL) -m644 $(LIBTCC1) win32/lib/*.def "$(DESTDIR)$(tccdir)/lib"
 	cp -r win32/include/. "$(DESTDIR)$(tccdir)/include"
 	cp -r win32/examples/. "$(DESTDIR)$(tccdir)/examples"
 else
-	$(INSTALL) -m644 libtcc1.a $(BCHECK_O) "$(DESTDIR)$(tccdir)"
+ifndef CONFIG_USE_LIBGCC
+	$(INSTALL) -m644 libtcc1.a "$(DESTDIR)$(tccdir)"
+endif
+	$(INSTALL) -m644 $(BCHECK_O) "$(DESTDIR)$(tccdir)"
 	$(INSTALL) -m644 stdarg.h stddef.h stdbool.h float.h varargs.h \
                    tcclib.h "$(DESTDIR)$(tccdir)/include"
 endif
diff --git a/configure b/configure
index 8517485..63328cc 100755
--- a/configure
+++ b/configure
@@ -19,6 +19,7 @@ TMPH="${TMPDIR1}/tcc-conf-${RANDOM}-$$-${RANDOM}.h"
 
 # default parameters
 build_cross="no"
+use_libgcc="no"
 prefix=""
 execprefix=""
 bindir=""
@@ -127,6 +128,8 @@ for opt do
   ;; 
   --enable-cross) build_cross="yes"
   ;;
+  --with-libgcc) use_libgcc="yes"
+  ;;
   esac
 done
 
@@ -224,6 +227,7 @@ echo "  --cross-prefix=PREFIX    use PREFIX for compile tools [$cross_prefix]"
 echo "  --sysroot=PREFIX         prepend PREFIX to library/include paths []"
 echo "  --cc=CC                  use C compiler CC [$cc]"
 echo "  --make=MAKE              use specified make [$make]"
+echo "  --with-libgcc            use /lib/libgcc_s.so.1 instead of libtcc1.a"
 echo ""
 #echo "NOTE: The object files are build at the place where configure is launched"
 exit 1
@@ -279,6 +283,7 @@ echo "CPU              $cpu"
 echo "Big Endian       $bigendian"
 echo "gprof enabled    $gprof"
 echo "cross compilers  $build_cross"
+echo "use libgcc       $use_libgcc"
 
 echo "Creating config.mak and config.h"
 
@@ -345,6 +350,10 @@ fi
 if test "$build_cross" = "yes" ; then
   echo "CONFIG_CROSS=yes" >> config.mak
 fi
+if test "$use_libgcc" = "yes" ; then
+  echo "#define CONFIG_USE_LIBGCC" >> $TMPH
+  echo "CONFIG_USE_LIBGCC=yes" >> config.mak
+fi
 version=`head $source_path/VERSION`
 echo "VERSION=$version" >>config.mak
 echo "#define TCC_VERSION \"$version\"" >> $TMPH
diff --git a/tccelf.c b/tccelf.c
index 7de8a48..aa2df9b 100644
--- a/tccelf.c
+++ b/tccelf.c
@@ -992,7 +992,9 @@ static void add_init_array_defines(TCCState *s1, const char *section_name)
 /* add tcc runtime libraries */
 static void tcc_add_runtime(TCCState *s1)
 {
+#if defined(CONFIG_TCC_BCHECK) || !defined(CONFIG_USE_LIBGCC)
     char buf[1024];
+#endif
 
 #ifdef CONFIG_TCC_BCHECK
     if (do_bounds_check) {
@@ -1028,8 +1030,12 @@ static void tcc_add_runtime(TCCState *s1)
     if (!s1->nostdlib) {
         tcc_add_library(s1, "c");
 
+#ifdef CONFIG_USE_LIBGCC
+        tcc_add_file(s1, CONFIG_SYSROOT "/lib/libgcc_s.so.1");
+#else
         snprintf(buf, sizeof(buf), "%s/%s", tcc_lib_path, "libtcc1.a");
         tcc_add_file(s1, buf);
+#endif
     }
     /* add crt end if not memory output */
     if (s1->output_type != TCC_OUTPUT_MEMORY && !s1->nostdlib) {