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Replaced LFSR_CAT_DAT with less-hacky lfsr_data_cat

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The name is not super important, but note lfsr_data_cat matches
lfsr_attr_cat, which is a nice bit of consistency.

The main change here is the adoption of correct field assignments
instead of a hacky cast forcing lfsr_data_t -> lfsr_cat_t. Tests were
passing even with optimizations, but I was concerned about the longevity
of this approach.

As a plus, we can actually assert on size fitting into a uint16_t thanks
to the inline function.

Unfortunately, this creates a surprising stack penalty:

           code          stack
  before: 33756           2624
  after:  33684 (-0.2%)   2824 (+7.6%)

I've also played around with instead reverting lfsr_data_from* ->
lfsr_cat_from*, and providing the inverse lfsr_cat_data, but nothing
gets us quite back to LFSR_CAT_DAT stack:

                  code          stack
  before:        33756           2624
  lfsr_data_cat: 33684 (-0.2%)   2824 (+7.6%)
  lfsr_cat_data: 33872 (+0.3%)   2736 (+4.3%)

This needs more investigation. Unfortunately I don't think we can revert
this, since correctness wins over code/stack costs...
This commit is contained in:
Christopher Haster
2024-05-09 15:50:31 -05:00
parent 85fad999b8
commit 250c1dd57e
1 changed files with 21 additions and 13 deletions
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lfs.c
+21 -13
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@@ -1440,9 +1440,6 @@ typedef struct lfsr_cat {
.u.buf.size=_size, \
.u.buf.buffer=(const void*)(_buffer)})
#define LFSR_CAT_DAT(_data) \
(*(lfsr_cat_t*)(lfsr_data_t[1]){_data})
#define LFSR_CAT_DATA_(_data) \
((lfsr_cat_t){ \
.u.cat.size=LFSR_CAT_ISCAT | 1, \
@@ -1461,6 +1458,17 @@ typedef struct lfsr_cat {
(const lfsr_data_t[]){__VA_ARGS__}, \
sizeof((const lfsr_data_t[]){__VA_ARGS__}) / sizeof(lfsr_data_t))
// data can be converted straight to a cat sometimes
static inline lfsr_cat_t lfsr_data_cat(lfsr_data_t data) {
// only simple data can be converted directly to cats
LFS_ASSERT(lfsr_data_isbuf(data));
LFS_ASSERT(lfsr_data_size(data) <= 0x7fff);
lfsr_cat_t cat;
cat.u.buf.size = data.u.buf.size;
cat.u.buf.buffer = data.u.buf.buffer;
return cat;
}
// cat helpers
static inline bool lfsr_cat_isbuf(lfsr_cat_t cat) {
return !(cat.u.size & LFSR_CAT_ISCAT);
@@ -1494,11 +1502,11 @@ static inline lfs_size_t lfsr_cat_size(lfsr_cat_t cat) {
#define LFSR_LLEB128_DSIZE 4
#define LFSR_CAT_LEB128(_word) \
LFSR_CAT_DAT( \
lfsr_data_cat( \
lfsr_data_fromleb128(_word, (uint8_t[LFSR_LEB128_DSIZE]){0}))
#define LFSR_CAT_LLEB128(_word) \
LFSR_CAT_DAT( \
lfsr_data_cat( \
lfsr_data_fromlleb128(_word, (uint8_t[LFSR_LLEB128_DSIZE]){0}))
static inline lfsr_data_t lfsr_data_fromleb128(uint32_t word,
@@ -1822,7 +1830,7 @@ typedef struct lfsr_ecksum {
#define LFSR_ECKSUM_DSIZE (4+4)
#define LFSR_CAT_ECKSUM_(_ecksum, _buffer) \
LFSR_CAT_DAT(lfsr_data_fromecksum(_ecksum, _buffer))
lfsr_data_cat(lfsr_data_fromecksum(_ecksum, _buffer))
#define LFSR_CAT_ECKSUM(_ecksum) \
LFSR_CAT_ECKSUM_(_ecksum, (uint8_t[LFSR_ECKSUM_DSIZE]){0})
@@ -1879,7 +1887,7 @@ static int lfsr_data_readecksum(lfs_t *lfs, lfsr_data_t *data,
#define LFSR_BPTR_DSIZE (4+5+4+4+4)
#define LFSR_CAT_BPTR_(_bptr, _buffer) \
LFSR_CAT_DAT(lfsr_data_frombptr(_bptr, _buffer))
lfsr_data_cat(lfsr_data_frombptr(_bptr, _buffer))
#define LFSR_CAT_BPTR(_bptr) \
LFSR_CAT_BPTR_(_bptr, (uint8_t[LFSR_BPTR_DSIZE]){0})
@@ -2091,7 +2099,7 @@ static inline bool lfsr_grm_isrm(const lfsr_grm_t *grm, lfsr_smid_t mid) {
}
#define LFSR_CAT_GRM_(_grm, _buffer) \
LFSR_CAT_DAT(lfsr_data_fromgrm(_grm, _buffer))
lfsr_data_cat(lfsr_data_fromgrm(_grm, _buffer))
#define LFSR_CAT_GRM(_grm) \
LFSR_CAT_GRM_(_grm, (uint8_t[LFSR_GRM_DSIZE]){0})
@@ -4162,7 +4170,7 @@ static inline int lfsr_btree_cmp(
#define LFSR_BRANCH_DSIZE (5+4+4)
#define LFSR_CAT_BRANCH_(_branch, _buffer) \
LFSR_CAT_DAT(lfsr_data_frombranch(_branch, _buffer))
lfsr_data_cat(lfsr_data_frombranch(_branch, _buffer))
#define LFSR_CAT_BRANCH(_branch) \
LFSR_CAT_BRANCH_(_branch, (uint8_t[LFSR_BRANCH_DSIZE]){0})
@@ -4235,7 +4243,7 @@ static int lfsr_data_readbranch(lfs_t *lfs, lfsr_data_t *data,
#define LFSR_BTREE_DSIZE (5+LFSR_BRANCH_DSIZE)
#define LFSR_CAT_BTREE_(_btree, _buffer) \
LFSR_CAT_DAT(lfsr_data_frombtree(_btree, _buffer))
lfsr_data_cat(lfsr_data_frombtree(_btree, _buffer))
#define LFSR_CAT_BTREE(_btree) \
LFSR_CAT_BTREE_(_btree, (uint8_t[LFSR_BTREE_DSIZE]){0})
@@ -5306,7 +5314,7 @@ static inline int lfsr_shrub_cmp(
#define LFSR_SHRUB_DSIZE (5+4)
#define LFSR_CAT_SHRUB_(_rbyd, _buffer) \
LFSR_CAT_DAT(lfsr_data_fromshrub(_rbyd, _buffer))
lfsr_data_cat(lfsr_data_fromshrub(_rbyd, _buffer))
#define LFSR_CAT_SHRUB(_rbyd) \
LFSR_CAT_SHRUB_(_rbyd, (uint8_t[LFSR_SHRUB_DSIZE]){0})
@@ -5511,7 +5519,7 @@ static inline bool lfsr_mptr_ismrootanchor(const lfsr_mptr_t *mptr) {
#define LFSR_MPTR_DSIZE (5+5)
#define LFSR_CAT_MPTR_(_mptr, _buffer) \
LFSR_CAT_DAT(lfsr_data_frommptr(_mptr, _buffer))
lfsr_data_cat(lfsr_data_frommptr(_mptr, _buffer))
#define LFSR_CAT_MPTR(_mptr) \
LFSR_CAT_MPTR_(_mptr, (uint8_t[LFSR_MPTR_DSIZE]){0})
@@ -8105,7 +8113,7 @@ typedef struct lfsr_geometry {
#define LFSR_GEOMETRY_DSIZE (4+5)
#define LFSR_CAT_GEOMETRY_(_geometry, _buffer) \
LFSR_CAT_DAT(lfsr_data_fromgeometry(_geometry, _buffer))
lfsr_data_cat(lfsr_data_fromgeometry(_geometry, _buffer))
#define LFSR_CAT_GEOMETRY(_geometry) \
LFSR_CAT_GEOMETRY_(_geometry, (uint8_t[LFSR_GEOMETRY_DSIZE]){0})