Github/littlefs
1
Fork 0
Code Actions Activity

Switched to passing lfsr_data_t by value again

Browse Source 
Thanks to poor compound literal optimization, it's actually cheaper to
pass lfsr_data_t by value everywhere, than to make all LFSR_DATA_*
macros lvalues:

  before: 34340           2896
  after:  34292 (-0.1%)   2896 (+0.0%)

Why are these two design choices linked? If lfsr_data_t is
pass-by-address, the rvalue/lvalue disinction is important because we
need to take the address of LFSR_DATA_* macros. If lfsr_data_t is
pass-by-value, rvalue/lvalue doesn't really matter because we, well,
pass by value.

To be honest, this is a bit of an excuse for better lfsr_data_t
ergonomics. It _is_ generally worse code-size wise to pass lfsr_data_t
by value, because most ABI optimizations stop at 2 words and
lfsr_data_t requires 3 words. But always passing lfsr_data_t by value
even if it is suboptimal makes for more consistent internal interfaces.

This also helps side-step a mistake I made earlier where I though
cat/fromimm/fromleb128 were the only LFSR_DATA_* macros that needed to
be lvalues to be consistent. THERE ARE MANY MORE LFSR_DATA_* macros,
every LFSR_DATA_FROMBLAH macro to be specific, and the resulting code
cost would be MUCH WORSE.

---

This also add lfsr_sprout_t to complement lfsr_bptr_t/lfsr_shrub_t/etc.
Unlike lfsr_data_t, lfsr_sprout_t _is_ pass-by-address

Actually that's the only difference, haha. lfsr_sprout_t is a typedef.

Though to be fair, by being pass-by-addres, lfsr_sprout_t keeps the
internal sprout/shrub/bptr/btree inferfaces consistent, and saves a bit
of code.
This commit is contained in:
Christopher Haster
2024-02-24 00:20:49 -06:00
parent 94f7d2549f
commit 35a4934178
4 changed files with 703 additions and 713 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tests/test_btree.toml
+24 -24
View File
@@ -3226,7 +3226,7 @@ code = '''
lfs_size_t weight_;
lfsr_data_t data_;
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF("aaa", 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF("aaa", 3),
&bid_, &tag_, &weight_, &data_) => LFS_ERR_NOENT;
'''
@@ -3262,7 +3262,7 @@ code = '''
lfs_size_t weight_;
lfsr_data_t data_;
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF("aaa", 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF("aaa", 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == 0);
@@ -3270,7 +3270,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, "0", 1) == 0);
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF("aab", 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF("aab", 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_LT;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == 0);
@@ -3315,7 +3315,7 @@ code = '''
lfs_size_t weight_;
lfsr_data_t data_;
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF("aaa", 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF("aaa", 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == 0);
@@ -3323,7 +3323,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, "0", 1) == 0);
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF("aab", 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF("aab", 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == 1);
@@ -3331,7 +3331,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, "1", 1) == 0);
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF("aac", 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF("aac", 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_LT;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == 1);
@@ -3380,7 +3380,7 @@ code = '''
lfs_size_t weight_;
lfsr_data_t data_;
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF("aaa", 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF("aaa", 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == 0);
@@ -3388,7 +3388,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, "0", 1) == 0);
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF("aab", 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF("aab", 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == 1);
@@ -3396,7 +3396,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, "1", 1) == 0);
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF("aac", 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF("aac", 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == 2);
@@ -3404,7 +3404,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, "2", 1) == 0);
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF("aad", 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF("aad", 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_LT;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == 2);
@@ -3453,7 +3453,7 @@ code = '''
lfs_size_t weight_;
lfsr_data_t data_;
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF("aaa", 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF("aaa", 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == 0);
@@ -3461,7 +3461,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, "0", 1) == 0);
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF("aab", 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF("aab", 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == 1);
@@ -3469,7 +3469,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, "1", 1) == 0);
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF("aac", 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF("aac", 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == 2);
@@ -3477,7 +3477,7 @@ code = '''
lfsr_data_read(&lfs, &data_, buffer, 4) => 1;
assert(memcmp(buffer, "2", 1) == 0);
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF("aad", 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF("aad", 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_LT;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == 2);
@@ -3549,7 +3549,7 @@ code = '''
'a'+((i/26/26) % 26), 'a'+((i/26) % 26), 'a'+(i % 26)
};
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF(name, 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF(name, 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == i);
@@ -3660,7 +3660,7 @@ code = '''
lfs_size_t weight_;
lfsr_data_t data_;
for (lfs_size_t i = 0; i < sim_size; i++) {
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF(sim_names[i], 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF(sim_names[i], 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == i);
@@ -3739,7 +3739,7 @@ code = '''
'a'+((i/26/26) % 26), 'a'+((i/26) % 26), 'a'+(i % 26)
};
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF(name, 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF(name, 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == i*W+W-1);
@@ -3892,7 +3892,7 @@ code = '''
weighted_bid += sim_weights[j];
}
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF(sim_names[i], 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF(sim_names[i], 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == weighted_bid+sim_weights[i]-1);
@@ -3971,7 +3971,7 @@ code = '''
lfs_size_t split_bid;
lfsr_data_t split_data;
lfs_scmp_t cmp = lfsr_btree_namelookup(&lfs, &btree,
&LFSR_DATA_BUF(name, 3),
LFSR_DATA_BUF(name, 3),
&split_bid, NULL, NULL, &split_data);
assert(cmp >= 0);
assert(cmp != LFS_CMP_EQ);
@@ -4065,7 +4065,7 @@ code = '''
lfs_size_t weight_;
lfsr_data_t data_;
for (lfs_size_t i = 0; i < sim_size; i++) {
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF(sim_names[i], 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF(sim_names[i], 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == i);
@@ -4156,7 +4156,7 @@ code = '''
lfs_size_t split_weight;
lfsr_data_t split_data;
lfs_scmp_t cmp = lfsr_btree_namelookup(&lfs, &btree,
&LFSR_DATA_BUF(name, 3),
LFSR_DATA_BUF(name, 3),
&split_bid, NULL, &split_weight, &split_data);
assert(cmp >= 0);
assert(cmp != LFS_CMP_EQ);
@@ -4286,7 +4286,7 @@ code = '''
weighted_bid += sim_weights[j];
}
lfsr_btree_namelookup(&lfs, &btree, &LFSR_DATA_BUF(sim_names[i], 3),
lfsr_btree_namelookup(&lfs, &btree, LFSR_DATA_BUF(sim_names[i], 3),
&bid_, &tag_, &weight_, &data_) => LFS_CMP_EQ;
assert(tag_ == LFSR_TAG_DATA);
assert(bid_ == weighted_bid+sim_weights[i]-1);
@@ -4392,7 +4392,7 @@ code = '''
printf("traversal: %d 0x%x data %d\n",
bid,
tinfo.tag,
lfsr_data_size(&tinfo.u.data));
lfsr_data_size(tinfo.u.data));
} else {
// well this shouldn't happen
@@ -4547,7 +4547,7 @@ code = '''
printf("traversal: %d 0x%x data %d\n",
bid,
tinfo.tag,
lfsr_data_size(&tinfo.u.data));
lfsr_data_size(tinfo.u.data));
} else {
// well this shouldn't happen
tests/test_rbyd.toml
+545 -545
View File
File diff suppressed because it is too large Load Diff