newlib: libm: workaround ar duplicate member behavior

GNU ar has undocumented behavior where it doesn't dedupe its inputs if
they're all on the same command line, so we have to dedupe ourselves.

2 files changed, 47 insertions, 5 deletions

diff --git a/newlib/Makefile.am b/newlib/Makefile.am
index 8025695..1a5123f 100644
--- a/newlib/Makefile.am
+++ b/newlib/Makefile.am
@@ -85,6 +85,25 @@ toollib_DATA = $(CRT0) $(CRT1)
 
 CLEANFILES += libg.a
 
+## GNU ar has undocumented behavior when specifying the same name multiple times
+## in a single invocation, so we have to dedupe ourselves.  The algorithm here:
+## - Generates the set of unique objects based on the basename.
+## - Favors objects later in the list (since machine objects come last).
+## - Outputs object list in same order as input for reproducibility.
+## https://sourceware.org/PR28917
+AWK_UNIQUE_OBJS = $(AWK) '{ \
+  for (i = NF; i > 0; --i) { \
+    split($$i, parts, "/"); \
+    name = parts[length(parts)]; \
+    if (!(name in seen)) { \
+      objs[i] = $$i; \
+      seen[name] = 1; \
+    } \
+  } \
+  for (i in objs) \
+    print objs[i]; \
+}'
+
 # The functions ldexp, frexp and modf are traditionally supplied in
 # both libc.a and libm.a.  We build them in libm.a and copy them over,
 # along with some required supporting routines.
@@ -122,8 +141,17 @@ libm_a_SOURCES =
 libm_a_CFLAGS = $(AM_CFLAGS) $(libm_a_CFLAGS_$(subst /,_,$(@D))) $(libm_a_CFLAGS_$(subst /,_,$(@D)_$(<F)))
 libm_a_CCASFLAGS = $(AM_CCASFLAGS) $(libm_a_CCASFLAGS_$(subst /,_,$(@D))) $(libm_a_CCASFLAGS_$(subst /,_,$(@D)_$(<F)))
 libm_a_CPPFLAGS = $(AM_CPPFLAGS) -I$(srcdir)/libm/common $(libm_a_CPPFLAGS_$(subst /,_,$(@D))) $(libm_a_CPPFLAGS_$(subst /,_,$(@D)_$(<F)))
+## Best to avoid libm_a_LIBADD entirely to avoid having 2 independent lists
+## with separate overriding behavior (libm_a_OBJECTS is the other).  See the
+## AWK_UNIQUE_OBJS comment aove for more details.
 $(libm_a_OBJECTS): stmp-targ-include
 
+libm.a: $(libm_a_OBJECTS) $(libm_a_DEPENDENCIES)
+	$(AM_V_at)rm -f $@
+	$(AM_V_AR)objs=`echo $(libm_a_OBJECTS) | $(AWK_UNIQUE_OBJS)` || exit $$?; \
+	  $(AR) $(ARFLAGS) $@ $$objs
+	$(AM_V_at)$(RANLIB) $@
+
 if HAVE_MULTISUBDIR
 $(BUILD_MULTISUBDIR):
 	$(MKDIR_P) $@
diff --git a/newlib/Makefile.in b/newlib/Makefile.in
index 2b60ef1..cc7afc7 100644
--- a/newlib/Makefile.in
+++ b/newlib/Makefile.in
@@ -1361,6 +1361,19 @@ toollib_LIBRARIES = libm.a \
 
 @HAVE_MULTISUBDIR_TRUE@BUILD_MULTISUBDIR = $(builddir)$(MULTISUBDIR)
 toollib_DATA = $(CRT0) $(CRT1)
+AWK_UNIQUE_OBJS = $(AWK) '{ \
+  for (i = NF; i > 0; --i) { \
+    split($$i, parts, "/"); \
+    name = parts[length(parts)]; \
+    if (!(name in seen)) { \
+      objs[i] = $$i; \
+      seen[name] = 1; \
+    } \
+  } \
+  for (i in objs) \
+    print objs[i]; \
+}'
+
 
 # The functions ldexp, frexp and modf are traditionally supplied in
 # both libc.a and libm.a.  We build them in libm.a and copy them over,
@@ -3248,11 +3261,6 @@ libm/machine/x86_64/libm_a-fetestexcept.$(OBJEXT):  \
 libm/machine/x86_64/libm_a-feupdateenv.$(OBJEXT):  \
 	libm/machine/x86_64/$(am__dirstamp)
 
-libm.a: $(libm_a_OBJECTS) $(libm_a_DEPENDENCIES) $(EXTRA_libm_a_DEPENDENCIES) 
-	$(AM_V_at)-rm -f libm.a
-	$(AM_V_AR)$(libm_a_AR) libm.a $(libm_a_OBJECTS) $(libm_a_LIBADD)
-	$(AM_V_at)$(RANLIB) libm.a
-
 mostlyclean-compile:
 	-rm -f *.$(OBJEXT)
 	-rm -f libm/common/*.$(OBJEXT)
@@ -8650,6 +8658,12 @@ libg.a: libc.a
 	$(AM_V_GEN)ln libc.a libg.a >/dev/null 2>/dev/null || cp libc.a libg.a
 $(libm_a_OBJECTS): stmp-targ-include
 
+libm.a: $(libm_a_OBJECTS) $(libm_a_DEPENDENCIES)
+	$(AM_V_at)rm -f $@
+	$(AM_V_AR)objs=`echo $(libm_a_OBJECTS) | $(AWK_UNIQUE_OBJS)` || exit $$?; \
+	  $(AR) $(ARFLAGS) $@ $$objs
+	$(AM_V_at)$(RANLIB) $@
+
 @HAVE_MULTISUBDIR_TRUE@$(BUILD_MULTISUBDIR):
 @HAVE_MULTISUBDIR_TRUE@	$(MKDIR_P) $@