On Mon, Jan 6, 2014 at 6:33 PM, Patrick Palka <patr...@parcs.ath.cx> wrote:
> Hi,
>
> The following tiny patch allows GCC to be built with the
> "--no-builtin-rules" GNU make flag. It replaces two usages of the
> automatic variable $* within the body of an explicit rule. Using $*
> inside the body of an explicit rule should be avoided[0] and, as in
> this scenario, may break an otherwise fine Makefile under the
> --no-builtin-rules flag.
>
> From what I inferred from the make manual[0], $* is functionally
> equivalent to $(basename $@) in this case. This patch therefore
> replaces $* with $(basename $@). I tested this patch by successfully
> performing a 3-stage bootstrap and a non-bootstrap build with and
> without the --no-builtin-rules flag. Without the patch, the build
> would fail during the compilation of libgcc/morestack.S under the
> --no-builtin-rules flag.
>
> This patch is interesting because the --no-builtin-rules flag may
> significantly shorten rebuild times. For example, on my machine an
> idempotent rebuild of the (non-bootstrapped) compiler takes 2s with
> the flag versus 2.6s without. Similarly, a rebuild after changing a
> single source file takes 20s versus 22s. This patch lets you
> seamlessly build and rebuild the compiler under the --no-builtin-rules
> flag without having to worry about possible build errors.
>
> [0]:
> http://www.gnu.org/software/make/manual/html_node/Automatic-Variables.html#Automatic-Variables
Oops, forgot the patch:
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,3 +1,8 @@
+2014-01-06 Patrick Palka <patr...@parcs.ath.cx>
+
+ * shared-object.mk ($(base)$(objext)): Don't use $*.
+ * static-object.mk ($(base)$(objext)): Likewise.
+
2014-01-02 Joseph Myers <jos...@codesourcery.com>
* config/rs6000/ibm-ldouble.c (__gcc_qdiv): Scale up arguments in
diff --git a/libgcc/shared-object.mk b/libgcc/shared-object.mk
index d9ee922..adbd165 100644
--- a/libgcc/shared-object.mk
+++ b/libgcc/shared-object.mk
@@ -25,7 +25,7 @@ endif
endif
$(base)$(objext): $o $(base).vis
- $(gcc_compile) -c -xassembler-with-cpp -include $*.vis $<
+ $(gcc_compile) -c -xassembler-with-cpp -include $(basename $@).vis $<
$(base).vis: $(base)_s$(objext)
$(gen-hide-list)
diff --git a/libgcc/static-object.mk b/libgcc/static-object.mk
index 4f53636..19c3006 100644
--- a/libgcc/static-object.mk
+++ b/libgcc/static-object.mk
@@ -25,7 +25,7 @@ endif
endif
$(base)$(objext): $o $(base).vis
- $(gcc_compile) -c -xassembler-with-cpp -include $*.vis $<
+ $(gcc_compile) -c -xassembler-with-cpp -include $(basename $@).vis $<
$(base).vis: $(base)_s$(objext)
$(gen-hide-list)
