attack the biggest stack users:

-mkfs_minix_main [busybox_unstripped]:                  4288
-mkfs_minix_main [busybox_unstripped]:                  4276
-grave [busybox_unstripped]:                            4260
(bzip2 users too - not listed)

price we pay in code size increase:
mainSort                                            2458    2515     +57
grave                                               1005    1058     +53
sendMTFValues                                       2177    2195     +18
BZ2_blockSort                                        122     125      +3
mkfs_minix_main                                     3070    3022     -48
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/1 up/down: 131/-48)            Total: 83 bytes

8 files changed, 85 insertions, 20 deletions

diff --git a/Makefile.custom b/Makefile.custom
index 5562ba396..a4db14172 100644
--- a/Makefile.custom
+++ b/Makefile.custom
@@ -90,7 +90,7 @@ objsizes: busybox_unstripped
 
 .PHONY: stksizes
 stksizes: busybox_unstripped
-        $(CROSS_COMPILE)objdump -d busybox_unstripped | $(srctree)/scripts/checkstack.pl $(ARCH)
+        $(CROSS_COMPILE)objdump -d busybox_unstripped | $(srctree)/scripts/checkstack.pl $(ARCH) | uniq
 
 .PHONY: bigdata
 bigdata: busybox_unstripped
diff --git a/archival/bz/blocksort.c b/archival/bz/blocksort.c
index cddbfcbea..0e73ffeba 100644
--- a/archival/bz/blocksort.c
+++ b/archival/bz/blocksort.c
@@ -721,7 +721,8 @@ void mainQSort3(uint32_t* ptr,
 #define CLEARMASK (~(SETMASK))
 
 static NOINLINE
-void mainSort(uint32_t*   ptr,
+void mainSort(EState* state,
+                uint32_t* ptr,
                 uint8_t*  block,
                 uint16_t* quadrant,
                 uint32_t* ftab,
@@ -729,13 +730,18 @@ void mainSort(uint32_t*   ptr,
                 int32_t*  budget)
 {
         int32_t  i, j, k, ss, sb;
-        int32_t  runningOrder[256];
-        Bool     bigDone[256];
-        int32_t  copyStart[256];
-        int32_t  copyEnd  [256];
         uint8_t  c1;
         int32_t  numQSorted;
         uint16_t s;
+        Bool     bigDone[256];
+        /* bbox: moved to EState to save stack
+        int32_t  runningOrder[256];
+        int32_t  copyStart[256];
+        int32_t  copyEnd  [256];
+        */
+#define runningOrder (state->mainSort__runningOrder)
+#define copyStart    (state->mainSort__copyStart)
+#define copyEnd      (state->mainSort__copyEnd)
 
         /*-- set up the 2-byte frequency table --*/
         /* was: for (i = 65536; i >= 0; i--) ftab[i] = 0; */
@@ -985,6 +991,9 @@ void mainSort(uint32_t*   ptr,
                         AssertH(((bbSize-1) >> shifts) <= 65535, 1002);
                 }
         }
+#undef runningOrder
+#undef copyStart
+#undef copyEnd
 }
 
 #undef BIGFREQ
@@ -1041,7 +1050,7 @@ void BZ2_blockSort(EState* s)
                  */
                 budget = nblock * ((wfact-1) / 3);
 
-                mainSort(ptr, block, quadrant, ftab, nblock, &budget);
+                mainSort(s, ptr, block, quadrant, ftab, nblock, &budget);
                 if (budget < 0) {
                         fallbackSort(s->arr1, s->arr2, ftab, nblock);
                 }
diff --git a/archival/bz/bzlib_private.h b/archival/bz/bzlib_private.h
index 02f177eb2..48676a391 100644
--- a/archival/bz/bzlib_private.h
+++ b/archival/bz/bzlib_private.h
@@ -178,13 +178,22 @@ typedef struct EState {
         uint8_t  selector   [BZ_MAX_SELECTORS];
         uint8_t  selectorMtf[BZ_MAX_SELECTORS];
 
-        uint8_t  len  [BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
-        int32_t  code [BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
-        int32_t  rfreq[BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
+        uint8_t  len[BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
+
+        /* stack-saving measures: these can be local, but they are too big */
+        int32_t  sendMTFValues__code [BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
+        int32_t  sendMTFValues__rfreq[BZ_N_GROUPS][BZ_MAX_ALPHA_SIZE];
 #if CONFIG_BZIP2_FEATURE_SPEED >= 5
         /* second dimension: only 3 needed; 4 makes index calculations faster */
-        uint32_t len_pack[BZ_MAX_ALPHA_SIZE][4];
+        uint32_t sendMTFValues__len_pack[BZ_MAX_ALPHA_SIZE][4];
 #endif
+        int32_t  BZ2_hbMakeCodeLengths__heap  [BZ_MAX_ALPHA_SIZE + 2];
+        int32_t  BZ2_hbMakeCodeLengths__weight[BZ_MAX_ALPHA_SIZE * 2];
+        int32_t  BZ2_hbMakeCodeLengths__parent[BZ_MAX_ALPHA_SIZE * 2];
+
+        int32_t  mainSort__runningOrder[256];
+        int32_t  mainSort__copyStart[256];
+        int32_t  mainSort__copyEnd[256];
 } EState;
 
 
@@ -203,7 +212,7 @@ static void
 BZ2_hbAssignCodes(int32_t*, uint8_t*, int32_t, int32_t, int32_t);
 
 static void
-BZ2_hbMakeCodeLengths(uint8_t*, int32_t*, int32_t, int32_t);
+BZ2_hbMakeCodeLengths(EState*, uint8_t*, int32_t*, int32_t, int32_t);
 
 /*-------------------------------------------------------------*/
 /*--- end                                   bzlib_private.h ---*/
diff --git a/archival/bz/compress.c b/archival/bz/compress.c
index b72edbbd4..640b8872b 100644
--- a/archival/bz/compress.c
+++ b/archival/bz/compress.c
@@ -264,13 +264,16 @@ void sendMTFValues(EState* s)
          * are also globals only used in this proc.
          * Made global to keep stack frame size small.
          */
+#define code     sendMTFValues__code
+#define rfreq    sendMTFValues__rfreq
+#define len_pack sendMTFValues__len_pack
 
         uint16_t cost[BZ_N_GROUPS];
         int32_t  fave[BZ_N_GROUPS];
 
         uint16_t* mtfv = s->mtfv;
 
-        alphaSize = s->nInUse+2;
+        alphaSize = s->nInUse + 2;
         for (t = 0; t < BZ_N_GROUPS; t++)
                 for (v = 0; v < alphaSize; v++)
                         s->len[t][v] = BZ_GREATER_ICOST;
@@ -453,7 +456,7 @@ void sendMTFValues(EState* s)
                 /* maxLen was changed from 20 to 17 in bzip2-1.0.3.  See
                  * comment in huffman.c for details. */
                 for (t = 0; t < nGroups; t++)
-                        BZ2_hbMakeCodeLengths(&(s->len[t][0]), &(s->rfreq[t][0]), alphaSize, 17 /*20*/);
+                        BZ2_hbMakeCodeLengths(s, &(s->len[t][0]), &(s->rfreq[t][0]), alphaSize, 17 /*20*/);
         }
 
         AssertH(nGroups < 8, 3002);
@@ -602,6 +605,9 @@ void sendMTFValues(EState* s)
                 selCtr++;
         }
         AssertH(selCtr == nSelectors, 3007);
+#undef code
+#undef rfreq
+#undef len_pack
 }
 
 
diff --git a/archival/bz/huffman.c b/archival/bz/huffman.c
index 02838c496..676b1af66 100644
--- a/archival/bz/huffman.c
+++ b/archival/bz/huffman.c
@@ -98,7 +98,8 @@ void DOWNHEAP1(int32_t *heap, int32_t *weight, int32_t nHeap)
 
 /*---------------------------------------------------*/
 static
-void BZ2_hbMakeCodeLengths(uint8_t *len,
+void BZ2_hbMakeCodeLengths(EState *s,
+                uint8_t *len,
                 int32_t *freq,
                 int32_t alphaSize,
                 int32_t maxLen)
@@ -110,9 +111,14 @@ void BZ2_hbMakeCodeLengths(uint8_t *len,
         int32_t nNodes, nHeap, n1, n2, i, j, k;
         Bool  tooLong;
 
+        /* bbox: moved to EState to save stack
         int32_t heap  [BZ_MAX_ALPHA_SIZE + 2];
         int32_t weight[BZ_MAX_ALPHA_SIZE * 2];
         int32_t parent[BZ_MAX_ALPHA_SIZE * 2];
+        */
+#define heap   (s->BZ2_hbMakeCodeLengths__heap)
+#define weight (s->BZ2_hbMakeCodeLengths__weight)
+#define parent (s->BZ2_hbMakeCodeLengths__parent)
 
         for (i = 0; i < alphaSize; i++)
                 weight[i+1] = (freq[i] == 0 ? 1 : freq[i]) << 8;
@@ -189,6 +195,9 @@ void BZ2_hbMakeCodeLengths(uint8_t *len,
                         weight[i] = j << 8;
                 }
         }
+#undef heap
+#undef weight
+#undef parent
 }
 
 
diff --git a/scripts/checkstack.pl b/scripts/checkstack.pl
index 6f455241a..55cdd78c1 100755
--- a/scripts/checkstack.pl
+++ b/scripts/checkstack.pl
@@ -126,7 +126,8 @@ while (my $line = <STDIN>) {
                 $addr =~ s/ /0/g;
                 $addr = "0x$addr";
 
-                my $intro = "$addr $func [$file]:";
+                # bbox: was: my $intro = "$addr $func [$file]:";
+                my $intro = "$func [$file]:";
                 my $padlen = 56 - length($intro);
                 while ($padlen > 0) {
                         $intro .= '     ';
diff --git a/shell/msh.c b/shell/msh.c
index 32953f4ed..9f95fe28a 100644
--- a/shell/msh.c
+++ b/shell/msh.c
@@ -735,6 +735,9 @@ struct globals {
         char filechar_cmdbuf[BUFSIZ];
         char line[LINELIM];
         char child_cmd[LINELIM];
+
+        char grave__var_name[LINELIM];
+        char grave__alt_value[LINELIM];
 };
 
 #define G (*ptr_to_globals)
@@ -746,6 +749,9 @@ struct globals {
 #define filechar_cmdbuf (G.filechar_cmdbuf)
 #define line            (G.line           )
 #define child_cmd       (G.child_cmd      )
+#define INIT_G() do { \
+        PTR_TO_GLOBALS = xzalloc(sizeof(G)); \
+} while (0)
 
 
 #ifdef MSHDEBUG
@@ -4042,8 +4048,12 @@ static int grave(int quoted)
                         ignore_once = 1;
                 if (*src == '$' && !ignore && !ignore_once) {
                         struct var *vp;
+                        /* moved to G to reduce stack usage
                         char var_name[LINELIM];
                         char alt_value[LINELIM];
+                        */
+#define var_name (G.grave__var_name)
+#define alt_value (G.grave__alt_value)
                         int var_index = 0;
                         int alt_index = 0;
                         char operator = 0;
@@ -4131,6 +4141,8 @@ static int grave(int quoted)
                                         count++;
                                 }
                         }
+#undef var_name
+#undef alt_value
                 } else {
                         *dest++ = *src++;
                         count++;
@@ -5173,7 +5185,8 @@ int msh_main(int argc, char **argv)
         char *name, **ap;
         int (*iof) (struct ioarg *);
 
-        PTR_TO_GLOBALS = xzalloc(sizeof(G));
+        INIT_G();
+
         sharedbuf.id = AFID_NOBUF;
         mainbuf.id = AFID_NOBUF;
         e.linep = line;
diff --git a/util-linux/mkfs_minix.c b/util-linux/mkfs_minix.c
index de9dde32b..35c0ccf5c 100644
--- a/util-linux/mkfs_minix.c
+++ b/util-linux/mkfs_minix.c
@@ -109,16 +109,22 @@ struct globals {
         unsigned long req_nr_inodes;
         unsigned currently_testing;
 
-
         char root_block[BLOCK_SIZE];
         char super_block_buffer[BLOCK_SIZE];
         char boot_block_buffer[512];
         unsigned short good_blocks_table[MAX_GOOD_BLOCKS];
         /* check_blocks(): buffer[] was the biggest static in entire bbox */
         char check_blocks_buffer[BLOCK_SIZE * TEST_BUFFER_BLOCKS];
-};
 
+        unsigned short ind_block1[BLOCK_SIZE >> 1];
+        unsigned short dind_block1[BLOCK_SIZE >> 1];
+        unsigned long ind_block2[BLOCK_SIZE >> 2];
+        unsigned long dind_block2[BLOCK_SIZE >> 2];
+};
 #define G (*ptr_to_globals)
+#define INIT_G() do { \
+        PTR_TO_GLOBALS = xzalloc(sizeof(G)); \
+} while (0)
 
 static ALWAYS_INLINE unsigned div_roundup(unsigned size, unsigned n)
 {
@@ -306,8 +312,12 @@ static void make_bad_inode(void)
         struct minix1_inode *inode = &INODE_BUF1[MINIX_BAD_INO];
         int i, j, zone;
         int ind = 0, dind = 0;
+        /* moved to globals to reduce stack usage
         unsigned short ind_block[BLOCK_SIZE >> 1];
         unsigned short dind_block[BLOCK_SIZE >> 1];
+        */
+#define ind_block (G.ind_block1)
+#define dind_block (G.dind_block1)
 
 #define NEXT_BAD (zone = next(zone))
 
@@ -351,6 +361,8 @@ static void make_bad_inode(void)
                 write_block(ind, (char *) ind_block);
         if (dind)
                 write_block(dind, (char *) dind_block);
+#undef ind_block
+#undef dind_block
 }
 
 #if ENABLE_FEATURE_MINIX2
@@ -359,8 +371,12 @@ static void make_bad_inode2(void)
         struct minix2_inode *inode = &INODE_BUF2[MINIX_BAD_INO];
         int i, j, zone;
         int ind = 0, dind = 0;
+        /* moved to globals to reduce stack usage
         unsigned long ind_block[BLOCK_SIZE >> 2];
         unsigned long dind_block[BLOCK_SIZE >> 2];
+        */
+#define ind_block (G.ind_block2)
+#define dind_block (G.dind_block2)
 
         if (!G.badblocks)
                 return;
@@ -401,6 +417,8 @@ static void make_bad_inode2(void)
                 write_block(ind, (char *) ind_block);
         if (dind)
                 write_block(dind, (char *) dind_block);
+#undef ind_block
+#undef dind_block
 }
 #else
 void make_bad_inode2(void);
@@ -613,7 +631,7 @@ int mkfs_minix_main(int argc, char **argv)
         char *str_i, *str_n;
         char *listfile = NULL;
 
-        PTR_TO_GLOBALS = xzalloc(sizeof(G));
+        INIT_G();
 /* default (changed to 30, per Linus's suggestion, Sun Nov 21 08:05:07 1993) */
         G.namelen = 30;
         G.dirsize = 32;