Replace run-time on-demand initialisation of PL_bitcount with a constant table.

(The table is 256 bytes; the run-time initialisation code is larger than this!)
Adapt generate_uudmap.c to generate the initalisation block for PL_bitcount,
writing the code to bitcount.h, using the same approach as uudmap.h.

To preserve binary compatibility:
for MULTIPLICITY:
  keep Ibitcount in the interpreter structure, but remove all the macros that
  access it. PL_bitcount is a new symbol in the object file, which won't clash
  with anything as that name wasn't used before.
otherwise:
  keep PL_bitcount as a char *, but initialise it at compile time to a new
  constant array PL_bitcount array. Remove the code that attempts to Safefree()
  it at interpreter destruction time.

1 files changed, 0 insertions, 14 deletions

diff --git a/pp_pack.c b/pp_pack.c
index 0895c9bba9..31cc8eb25f 100644
--- a/pp_pack.c
+++ b/pp_pack.c
@@ -1477,20 +1477,6 @@ S_unpack_rec(pTHX_ tempsym_t* symptr, const char *s, const char *strbeg, const c
 	    if (howlen == e_star || len > (strend - s) * 8)
 		len = (strend - s) * 8;
 	    if (checksum) {
-		if (!PL_bitcount) {
-		    int bits;
-		    Newxz(PL_bitcount, 256, char);
-		    for (bits = 1; bits < 256; bits++) {
-			if (bits & 1)	PL_bitcount[bits]++;
-			if (bits & 2)	PL_bitcount[bits]++;
-			if (bits & 4)	PL_bitcount[bits]++;
-			if (bits & 8)	PL_bitcount[bits]++;
-			if (bits & 16)	PL_bitcount[bits]++;
-			if (bits & 32)	PL_bitcount[bits]++;
-			if (bits & 64)	PL_bitcount[bits]++;
-			if (bits & 128)	PL_bitcount[bits]++;
-		    }
-		}
 		if (utf8)
 		    while (len >= 8 && s < strend) {
 			cuv += PL_bitcount[uni_to_byte(aTHX_ &s, strend, datumtype)];