[m-dev.] diff: fix portability problem with `-lm'

[Fergus Henderson]

On 24-Sep-2000, Tyson Dowd <trd at cs.mu.OZ.AU> wrote:
> On 23-Sep-2000, Fergus Henderson <fjh at cs.mu.OZ.AU> wrote:
> > On 22-Sep-2000, Fergus Henderson <fjh at cs.mu.OZ.AU> wrote:
> > > Estimated hours taken: 1
> > > 
> > > Fix a portability problem: we were assuming that `-lm' would work, but
> > > on some systems, e.g. MacOS X (Darwin), it doesn't.
> > 
> > In my haste to get down to the pub on Friday night,
> > I committed that one a little too hastily...
> > 
> > configure.in:
> > 	Fix a bug in my previous fix for the `-lm' portability problem.
> > 	I was using the wrong syntax for variable references (Make syntax
> > 	rather than sh syntax).
> 
> Unfortunately this is wrong too.
> 
> SHARED_LIBS is used in Mmake.common and scripts/ml
> 
> So it has to work both in sh and make.

Ah, ouch.

> This is one solution, but I don't like it very much.
> 
> Index: configure.in
> ===================================================================
> RCS file: /home/mercury1/repository/mercury/configure.in,v
> retrieving revision 1.227
> diff -u -r1.227 configure.in
> --- configure.in	2000/09/23 12:59:10	1.227
> +++ configure.in	2000/09/24 07:13:22
> @@ -2018,7 +2018,8 @@
>  # see Mmake.common.in for documentation on the meaning of these variables
>  LINK_SHARED_OBJ="$CC -shared"
>  LINK_SHARED_OBJ_SH="$CC -shared"
> -SHARED_LIBS='`gcc -print-libgcc-file-name` $MATH_LIB -lc'
> +SHARED_LIBS='`gcc -print-libgcc-file-name` $(MATH_LIB) -lc'
> +SHARED_LIBS_SH='`gcc -print-libgcc-file-name` $MATH_LIB -lc'
>  EXE_RPATH_OPT="-Wl,-rpath,"
>  EXE_RPATH_SEP=" -Wl,-rpath,"
>  SHLIB_RPATH_OPT="-Wl,-rpath,"
...
> Index: scripts/ml.in
> ===================================================================
> RCS file: /home/mercury1/repository/mercury/scripts/ml.in,v
> retrieving revision 1.84
> diff -u -r1.84 ml.in
> --- scripts/ml.in	2000/09/22 08:27:30	1.84
> +++ scripts/ml.in	2000/09/24 07:13:36
> @@ -31,7 +31,7 @@
>  LINK_SHARED_OBJ=${MERCURY_LINK_SHARED_OBJ="@LINK_SHARED_OBJ_SH@"}
>  SHLIB_RPATH_OPT=${MERCURY_SHLIB_RPATH_OPT="@SHLIB_RPATH_OPT@"}
>  SHLIB_RPATH_SEP=${MERCURY_SHLIB_RPATH_SEP="@SHLIB_RPATH_SEP@"}
> -SHARED_LIBS=${MERCURY_SHARED_LIBS="@SHARED_LIBS@"}
> +SHARED_LIBS=${MERCURY_SHARED_LIBS="@SHARED_LIBS_SH@"}
>  TMPDIR=${TMPDIR=/tmp}
>  MATH_LIB=${MERCURY_MATH_LIB="@MATH_LIB@"}

That one still doesn't quite work, I think, because @SHARED_LIBS_SH@
will contain a reference to $MATH_LIB, but it gets expanded before
MATH_LIB has been set.  Another problem is that we need to pass on
SHARED_LIB_SH in bindist/bindist.build_vars.in.

However, I think both of those problems are easily fixed.
For the first one, we just need to swap the order of those variable settings.

Another solution -- which I started working on before I saw your email --
would be to change configure.in so that MATH_LIB gets expanded at configure
time rather than when ml/mmake is invoked.  But I prefer your solution.

I'll go ahead and commit your solution, modified by the two fixes noted
above, and together with a fix to the other problem that you mentioned
in your other mail.

----------

Estimated hours taken: 0.75 (about half of it by Tyson)

configure.in:
	Fix two bugs in my previous fix for the `-lm' portability problem:
	- AC_CHECK_LIB should have been AC_HAVE_LIBRARY
	- SHARED_LIB needed to be valid as *both* Make and sh syntax.
	  To fix this one, we've added a new variable SHARED_LIB_SH
	  which has the sh-syntax version of it, while SHARED_LIB now
	  has the Make-syntax version of it.

scripts/ml.in:
	Use SHARED_LIB_SH rather than SHARED_LIB.

bindist/bindist.build_vars.in:
	Pass on the value of SHARED_LIB_SH.

Workspace: /home/pgrad/fjh/ws/hg
Index: bindist/bindist.build_vars.in
===================================================================
RCS file: /home/mercury1/repository/mercury/bindist/bindist.build_vars.in,v
retrieving revision 1.15
diff -u -d -r1.15 bindist.build_vars.in
--- bindist/bindist.build_vars.in	2000/09/22 08:23:40	1.15
+++ bindist/bindist.build_vars.in	2000/09/24 08:45:35
@@ -31,6 +31,7 @@
 EXT_FOR_SHARED_LIB="@EXT_FOR_SHARED_LIB@"
 CFLAGS_FOR_PIC="@CFLAGS_FOR_PIC@"
 SHARED_LIBS='@SHARED_LIBS@'
+SHARED_LIBS_SH='@SHARED_LIBS_SH@'
 HAVE_DELAY_SLOT="@HAVE_DELAY_SLOT@"
 DEFAULT_RM_C="@DEFAULT_RM_C@"
 ERROR_UNDEFINED="@ERROR_UNDEFINED@"
Index: configure.in
===================================================================
RCS file: /home/mercury1/repository/mercury/configure.in,v
retrieving revision 1.227
diff -u -d -r1.227 configure.in
--- configure.in	2000/09/23 12:59:10	1.227
+++ configure.in	2000/09/24 08:43:29
@@ -224,7 +224,7 @@
 AC_RETSIGTYPE
 #-----------------------------------------------------------------------------#
 # Check for `-lm': some systems, e.g. MacOS X (Darwin), don't have it.
-AC_CHECK_LIB(m,[MATH_LIB=-lm],[MATH_LIB=])
+AC_HAVE_LIBRARY(m,[MATH_LIB=-lm],[MATH_LIB=])
 AC_SUBST(MATH_LIB)
 #-----------------------------------------------------------------------------#
 AC_MSG_CHECKING(for use of a Microsoft compiler)
@@ -2018,7 +2018,8 @@
 # see Mmake.common.in for documentation on the meaning of these variables
 LINK_SHARED_OBJ="$CC -shared"
 LINK_SHARED_OBJ_SH="$CC -shared"
-SHARED_LIBS='`gcc -print-libgcc-file-name` $MATH_LIB -lc'
+SHARED_LIBS='`gcc -print-libgcc-file-name` $(MATH_LIB) -lc'
+SHARED_LIBS_SH='`gcc -print-libgcc-file-name` $MATH_LIB -lc'
 EXE_RPATH_OPT="-Wl,-rpath,"
 EXE_RPATH_SEP=" -Wl,-rpath,"
 SHLIB_RPATH_OPT="-Wl,-rpath,"
@@ -2055,7 +2056,8 @@
 		;;
 	sparc-sun-solaris2.*)
 		AC_MSG_RESULT(yes)
-		SHARED_LIBS="$MATH_LIB -lc"	# don't link in libgcc.a
+		SHARED_LIBS="$(MATH_LIB) -lc"	# don't link in libgcc.a
+		SHARED_LIBS_SH="$MATH_LIB -lc"	# don't link in libgcc.a
 		LINK_SHARED_OBJ="$CC -G"
 		LINK_SHARED_OBJ_SH="$CC -G"
 		ERROR_UNDEFINED="-Wl,-z,defs"
@@ -2209,6 +2211,7 @@
 AC_SUBST(EXT_FOR_EXE)
 AC_SUBST(USE_DLLS)
 AC_SUBST(SHARED_LIBS)
+AC_SUBST(SHARED_LIBS_SH)
 AC_SUBST(DEFAULT_RM_C)
 AC_SUBST(LIBRARY_RM_C)
 if test $USE_DLLS = "yes"; then
Index: scripts/ml.in
===================================================================
RCS file: /home/mercury1/repository/mercury/scripts/ml.in,v
retrieving revision 1.84
diff -u -d -r1.84 ml.in
--- scripts/ml.in	2000/09/22 08:27:30	1.84
+++ scripts/ml.in	2000/09/24 08:45:16
@@ -31,9 +31,11 @@
 LINK_SHARED_OBJ=${MERCURY_LINK_SHARED_OBJ="@LINK_SHARED_OBJ_SH@"}
 SHLIB_RPATH_OPT=${MERCURY_SHLIB_RPATH_OPT="@SHLIB_RPATH_OPT@"}
 SHLIB_RPATH_SEP=${MERCURY_SHLIB_RPATH_SEP="@SHLIB_RPATH_SEP@"}
-SHARED_LIBS=${MERCURY_SHARED_LIBS="@SHARED_LIBS@"}
 TMPDIR=${TMPDIR=/tmp}
 MATH_LIB=${MERCURY_MATH_LIB="@MATH_LIB@"}
+# Note: the setting of SHARED_LIBS needs to come after the setting of MATH_LIB,
+# since @SHARED_LIBS_SH@ may refer to $MATH_LIB.
+SHARED_LIBS=${MERCURY_SHARED_LIBS="@SHARED_LIBS_SH@"}
 
 # When compiling in the hlc.gc grade using the Microsoft Visual C
 # compiler, the default maximum stack size of 4Mb is too low for a
-- 
Fergus Henderson <fjh at cs.mu.oz.au>  |  "I have always known that the pursuit
WWW: <http://www.cs.mu.oz.au/~fjh>  |  of excellence is a lethal habit"
PGP: finger fjh at 128.250.37.3        |     -- the last words of T. S. Garp.
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