work around compiler bug on CX/UX (perl5.004_01)

This patch provides a work-around for a compiler bug on CX/UX systems (which
shows up as a failure in the 'w' format of pack). The
CXUX_BROKEN_CONSTANT_CONVERT ifdef flag is added to the hints/cxux.sh
compiler and pp.c is modified to avoid a compile time constant conversion
which fails based on that ifdef.

While I was in the hints file, I also added the magical
-Qtarget=M88110compat compiler option which makes it build code that will
run on both 88110 and 88100 CX/UX machines interchangably.

This patch was generated from a brand new copy of perl5.004_01, so I'm
confident there are no extraneous changes that slipped in. I even built
and tested and it passed all tests.

(I decided to go with option #3 in my previous mail about how to do the patch).

If its too late for 5.004_02, I wouldn't worry - it isn't very critical.

p5p-msgid: 9707301934.AA18594@amber.ssd.hcsc.com

diff --git a/hints/cxux.sh b/hints/cxux.sh
index 42bfe5d..e3ac086 100644 (file)
--- a/hints/cxux.sh
+++ b/hints/cxux.sh
@@ -61,16 +61,18 @@ libswanted=`echo ' '$libswanted' ' | sed -e 's/ malloc / /'`
 #
 glibpth="/usr/sde/elf/usr/lib $glibpth"
 
-# Need to use Concurrent cc for most of these options to be meaningful (if you
-# want to get this to work with gcc, you're on your own :-). Passing
+# Need to use Concurrent cc for most of these options to be meaningful (if
+# you want to get this to work with gcc, you're on your own :-). Passing
 # -Bexport to the linker when linking perl is important because it leaves
 # the interpreter internal symbols visible to the shared libs that will be
-# loaded on demand (and will try to reference those symbols). The -u
-# option to drag 'sigaction' into the perl main program is to make sure
-# it gets defined for the posix shared library (for some reason sigaction
-# is static, rather than being defined in libc.so.1).
+# loaded on demand (and will try to reference those symbols). The -u option
+# to drag 'sigaction' into the perl main program is to make sure it gets
+# defined for the posix shared library (for some reason sigaction is static,
+# rather than being defined in libc.so.1). The 88110compat option makes sure
+# the code will run on both 88100 and 88110 machines. The define is added to
+# trigger a work around for a compiler bug which shows up in pp.c.
 #
-cc='/bin/cc -Xa'
+cc='/bin/cc -Xa -Qtarget=M88110compat -DCXUX_BROKEN_CONSTANT_CONVERT'
 cccdlflags='-Zelf -Zpic'
 ccdlflags='-Zelf -Zlink=dynamic -Wl,-Bexport -u sigaction'
 lddlflags='-Zlink=so'

diff --git a/pp.c b/pp.c
index d791c4b..a0b337a 100644 (file)
--- a/pp.c
+++ b/pp.c
@@ -16,6 +16,17 @@
 #include "perl.h"
 
 /*
+ * The compiler on Concurrent CX/UX systems has a subtle bug which only
+ * seems to show up when compiling pp.c - it generates the wrong double
+ * precision constant value for (double)UV_MAX when used inline in the body
+ * of the code below, so this makes a static variable up front (which the
+ * compiler seems to get correct) and uses it in place of UV_MAX below.
+ */
+#ifdef CXUX_BROKEN_CONSTANT_CONVERT
+static double UV_MAX_cxux = ((double)UV_MAX);
+#endif
+
+/*
  * Types used in bitwise operations.
  *
  * Normally we'd just use IV and UV.  However, some hardware and
@@ -3714,8 +3725,12 @@ PP(pp_pack)
 #ifdef BW_BITS
                    adouble <= BW_MASK
 #else
+#ifdef CXUX_BROKEN_CONSTANT_CONVERT
+                   adouble <= UV_MAX_cxux
+#else
                    adouble <= UV_MAX
 #endif
+#endif
                    )
                {
                    char   buf[1 + sizeof(UV)];