Add support for IBM Z hardware-accelerated deflate

IBM Z mainframes starting from version z15 provide DFLTCC instruction,
which implements deflate algorithm in hardware with estimated
compression and decompression performance orders of magnitude faster
than the current zlib and ratio comparable with that of level 1.

This patch adds DFLTCC support to zlib. In order to enable it, the
following build commands should be used:

    $ ./configure --dfltcc
    $ make

When built like this, zlib would compress in hardware on level 1, and in
software on all other levels. Decompression will always happen in
hardware. In order to enable DFLTCC compression for levels 1-6 (i.e. to
make it used by default) one could either configure with
--dfltcc-level-mask=0x7e or set the environment variable
DFLTCC_LEVEL_MASK to 0x7e at run time.

Two DFLTCC compression calls produce the same results only when they
both are made on machines of the same generation, and when the
respective buffers have the same offset relative to the start of the
page. Therefore care should be taken when using hardware compression
when reproducible results are desired. One such use case - reproducible
software builds - is handled explicitly: when SOURCE_DATE_EPOCH
environment variable is set, the hardware compression is disabled.

DFLTCC does not support every single zlib feature, in particular:

    * inflate(Z_BLOCK) and inflate(Z_TREES)
    * inflateMark()
    * inflatePrime()
    * inflateSyncPoint()

When used, these functions will either switch to software, or, in case
this is not possible, gracefully fail.

This patch tries to add DFLTCC support in the least intrusive way.
All SystemZ-specific code is placed into a separate file, but
unfortunately there is still a noticeable amount of changes in the
main zlib code. Below is the summary of these changes.

DFLTCC takes as arguments a parameter block, an input buffer, an output
buffer and a window. Since DFLTCC requires parameter block to be
doubleword-aligned, and it's reasonable to allocate it alongside
deflate and inflate states, ZALLOC_STATE, ZFREE_STATE and ZCOPY_STATE
macros were introduced in order to encapsulate the allocation details.
The same is true for window, for which ZALLOC_WINDOW and
TRY_FREE_WINDOW macros were introduced.

Software and hardware window formats do not match, therefore,
deflateSetDictionary(), deflateGetDictionary(), inflateSetDictionary()
and inflateGetDictionary() need special handling, which is triggered
using DEFLATE_SET_DICTIONARY_HOOK, DEFLATE_GET_DICTIONARY_HOOK,
INFLATE_SET_DICTIONARY_HOOK and INFLATE_GET_DICTIONARY_HOOK macros.

deflateResetKeep() and inflateResetKeep() now update the DFLTCC
parameter block, which is allocated alongside zlib state, using
the new DEFLATE_RESET_KEEP_HOOK and INFLATE_RESET_KEEP_HOOK macros.

The new DEFLATE_PARAMS_HOOK switches between hardware and software
deflate implementations when deflateParams() arguments demand this.

The new INFLATE_PRIME_HOOK, INFLATE_MARK_HOOK and
INFLATE_SYNC_POINT_HOOK macros make the respective unsupported calls
gracefully fail.

The algorithm implemented in hardware has different compression ratio
than the one implemented in software. In order for deflateBound() to
return the correct results for the hardware implementation, the new
DEFLATE_BOUND_ADJUST_COMPLEN and DEFLATE_NEED_CONSERVATIVE_BOUND macros
were introduced.

Actual compression and decompression are handled by the new DEFLATE_HOOK
and INFLATE_TYPEDO_HOOK macros. Since inflation with DFLTCC manages the
window on its own, calling updatewindow() is suppressed using the new
INFLATE_NEED_UPDATEWINDOW() macro.

In addition to compression, DFLTCC computes CRC-32 and Adler-32
checksums, therefore, whenever it's used, software checksumming needs to
be suppressed using the new DEFLATE_NEED_CHECKSUM and
INFLATE_NEED_CHECKSUM macros.

DFLTCC will refuse to write an End-of-block Symbol if there is no input
data, thus in some cases it is necessary to do this manually. In order
to achieve this, send_bits, bi_reverse, bi_windup and flush_pending
were promoted from local to ZLIB_INTERNAL. Furthermore, since block and
stream termination must be handled in software as well, block_state enum
was moved to deflate.h.

Since the first call to dfltcc_inflate already needs the window, and it
might be not allocated yet, inflate_ensure_window was factored out of
updatewindow and made ZLIB_INTERNAL.

Makefile.in

@@ -139,6 +139,14 @@ match.lo: match.S
 	mv _match.o match.lo
 	rm -f _match.s
 
+dfltcc.o: $(SRCDIR)contrib/s390/dfltcc.c $(SRCDIR)zlib.h zconf.h
+	$(CC) $(CFLAGS) $(ZINC) -c -o $@ $(SRCDIR)contrib/s390/dfltcc.c
+
+dfltcc.lo: $(SRCDIR)contrib/s390/dfltcc.c $(SRCDIR)zlib.h zconf.h
+	-@mkdir objs 2>/dev/null || test -d objs
+	$(CC) $(SFLAGS) $(ZINC) -DPIC -c -o objs/dfltcc.o $(SRCDIR)contrib/s390/dfltcc.c
+	-@mv objs/dfltcc.o $@
+
 crc32_test.o: $(SRCDIR)test/crc32_test.c $(SRCDIR)zlib.h zconf.h
 	$(CC) $(CFLAGS) $(ZINCOUT) -c -o $@ $(SRCDIR)test/crc32_test.c
 

compress.c

@@ -5,9 +5,15 @@
 
 /* @(#) $Id$ */
 
-#define ZLIB_INTERNAL
+#include "zutil.h"
 #include "zlib.h"
 
+#ifdef DFLTCC
+#  include "contrib/s390/dfltcc.h"
+#else
+#define DEFLATE_BOUND_COMPLEN(source_len) 0
+#endif
+
 /* ===========================================================================
      Compresses the source buffer into the destination buffer. The level
    parameter has the same meaning as in deflateInit.  sourceLen is the byte
@@ -81,6 +87,12 @@ int ZEXPORT compress(dest, destLen, source, sourceLen)
 uLong ZEXPORT compressBound(sourceLen)
     uLong sourceLen;
 {
+    uLong complen = DEFLATE_BOUND_COMPLEN(sourceLen);
+
+    if (complen > 0)
+	/* Architecture-specific code provided an upper bound. */
+	return complen + ZLIB_WRAPLEN;
+
     return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
            (sourceLen >> 25) + 13;
 }

configure

@@ -118,6 +118,7 @@ case "$1" in
       echo '  configure [--const] [--zprefix] [--prefix=PREFIX]  [--eprefix=EXPREFIX]' | tee -a configure.log
       echo '    [--static] [--64] [--libdir=LIBDIR] [--sharedlibdir=LIBDIR]' | tee -a configure.log
       echo '    [--includedir=INCLUDEDIR] [--archs="-arch i386 -arch x86_64"]' | tee -a configure.log
+      echo '    [--dfltcc] [--dfltcc-level-mask=MASK]' | tee -a configure.log
         exit 0 ;;
     -p*=* | --prefix=*) prefix=`echo $1 | sed 's/.*=//'`; shift ;;
     -e*=* | --eprefix=*) exec_prefix=`echo $1 | sed 's/.*=//'`; shift ;;
@@ -142,6 +143,16 @@ case "$1" in
     -w* | --warn) warn=1; shift ;;
     -d* | --debug) debug=1; shift ;;
     --sanitize) sanitize=1; shift ;;
+    --dfltcc)
+      CFLAGS="$CFLAGS -DDFLTCC"
+      OBJC="$OBJC dfltcc.o"
+      PIC_OBJC="$PIC_OBJC dfltcc.lo"
+      shift
+      ;;
+    --dfltcc-level-mask=*)
+      CFLAGS="$CFLAGS -DDFLTCC_LEVEL_MASK=`echo $1 | sed 's/.*=//'`"
+      shift
+      ;;
     *)
       echo "unknown option: $1" | tee -a configure.log
       echo "$0 --help for help" | tee -a configure.log
@@ -828,6 +839,19 @@ EOF
   fi
 fi
 
+# Check whether sys/sdt.h is available
+cat > $test.c << EOF
+#include <sys/sdt.h>
+int main() { return 0; }
+EOF
+if try $CC -c $CFLAGS $test.c; then
+    echo "Checking for sys/sdt.h ... Yes." | tee -a configure.log
+    CFLAGS="$CFLAGS -DHAVE_SYS_SDT_H"
+    SFLAGS="$SFLAGS -DHAVE_SYS_SDT_H"
+else
+    echo "Checking for sys/sdt.h ... No." | tee -a configure.log
+fi
+
 # test to see if we can use a gnu indirection function to detect and load optimized code at runtime
 echo >> configure.log
 cat > $test.c <<EOF

contrib/README.contrib

@@ -55,6 +55,10 @@ puff/       by Mark Adler <[email protected]>
         Small, low memory usage inflate.  Also serves to provide an
         unambiguous description of the deflate format.
 
+s390/       by Ilya Leoshkevich <[email protected]>
+        Hardware-accelerated deflate on IBM Z with DEFLATE CONVERSION CALL
+        instruction.
+
 testzlib/   by Gilles Vollant <[email protected]>
         Example of the use of zlib
 

contrib/s390/README.txt

@@ -0,0 +1,17 @@
+IBM Z mainframes starting from version z15 provide DFLTCC instruction,
+which implements deflate algorithm in hardware with estimated
+compression and decompression performance orders of magnitude faster
+than the current zlib and ratio comparable with that of level 1.
+
+This directory adds DFLTCC support. In order to enable it, the following
+build commands should be used:
+
+    $ ./configure --dfltcc
+    $ make
+
+When built like this, zlib would compress in hardware on level 1, and in
+software on all other levels. Decompression will always happen in
+hardware. In order to enable DFLTCC compression for levels 1-6 (i.e. to
+make it used by default) one could either configure with
+--dfltcc-level-mask=0x7e or set the environment variable
+DFLTCC_LEVEL_MASK to 0x7e at run time.