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Reduce function size in fast & dfast

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Take the same approach as in PR #2828 [0] to remove functions that force
inline many function bodies and `switch`. Instead, create one function per
"template" combination, and then switch between these functions. This
allows the compiler to break the large function into many small
functions, which generally helps codegen.

Also, in the `extDict` modes when there is no ext-dict, call the top
level function instead of the force inlined one, to save on code size.

I'm specifically doing this because gcc on the parisc architecture doesn't
handle the large function body well, and ends up using a lot of excess
stack space. Outlining these functions fixes it.
This commit is contained in:
Nick Terrell
2021-11-15 19:05:48 -08:00
parent ddae153947
commit 802ea885ef
2 changed files with 71 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lib/compress/zstd_double_fast.c
+35 -13
View File
@@ -468,6 +468,24 @@ _match_stored:
return (size_t)(iend - anchor);
}
#define ZSTD_GEN_DFAST_FN(dictMode, mls) \
static size_t ZSTD_compressBlock_doubleFast_##dictMode##_##mls( \
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM], \
void const* src, size_t srcSize) \
{ \
return ZSTD_compressBlock_doubleFast_##dictMode##_generic(ms, seqStore, rep, src, srcSize, mls); \
}
ZSTD_GEN_DFAST_FN(noDict, 4)
ZSTD_GEN_DFAST_FN(noDict, 5)
ZSTD_GEN_DFAST_FN(noDict, 6)
ZSTD_GEN_DFAST_FN(noDict, 7)
ZSTD_GEN_DFAST_FN(dictMatchState, 4)
ZSTD_GEN_DFAST_FN(dictMatchState, 5)
ZSTD_GEN_DFAST_FN(dictMatchState, 6)
ZSTD_GEN_DFAST_FN(dictMatchState, 7)
size_t ZSTD_compressBlock_doubleFast(
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
@@ -478,13 +496,13 @@ size_t ZSTD_compressBlock_doubleFast(
{
default: /* includes case 3 */
case 4 :
return ZSTD_compressBlock_doubleFast_noDict_generic(ms, seqStore, rep, src, srcSize, 4);
return ZSTD_compressBlock_doubleFast_noDict_4(ms, seqStore, rep, src, srcSize);
case 5 :
return ZSTD_compressBlock_doubleFast_noDict_generic(ms, seqStore, rep, src, srcSize, 5);
return ZSTD_compressBlock_doubleFast_noDict_5(ms, seqStore, rep, src, srcSize);
case 6 :
return ZSTD_compressBlock_doubleFast_noDict_generic(ms, seqStore, rep, src, srcSize, 6);
return ZSTD_compressBlock_doubleFast_noDict_6(ms, seqStore, rep, src, srcSize);
case 7 :
return ZSTD_compressBlock_doubleFast_noDict_generic(ms, seqStore, rep, src, srcSize, 7);
return ZSTD_compressBlock_doubleFast_noDict_7(ms, seqStore, rep, src, srcSize);
}
}
@@ -498,13 +516,13 @@ size_t ZSTD_compressBlock_doubleFast_dictMatchState(
{
default: /* includes case 3 */
case 4 :
return ZSTD_compressBlock_doubleFast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 4);
return ZSTD_compressBlock_doubleFast_dictMatchState_4(ms, seqStore, rep, src, srcSize);
case 5 :
return ZSTD_compressBlock_doubleFast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 5);
return ZSTD_compressBlock_doubleFast_dictMatchState_5(ms, seqStore, rep, src, srcSize);
case 6 :
return ZSTD_compressBlock_doubleFast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 6);
return ZSTD_compressBlock_doubleFast_dictMatchState_6(ms, seqStore, rep, src, srcSize);
case 7 :
return ZSTD_compressBlock_doubleFast_dictMatchState_generic(ms, seqStore, rep, src, srcSize, 7);
return ZSTD_compressBlock_doubleFast_dictMatchState_7(ms, seqStore, rep, src, srcSize);
}
}
@@ -540,7 +558,7 @@ static size_t ZSTD_compressBlock_doubleFast_extDict_generic(
/* if extDict is invalidated due to maxDistance, switch to "regular" variant */
if (prefixStartIndex == dictStartIndex)
return ZSTD_compressBlock_doubleFast_noDict_generic(ms, seqStore, rep, src, srcSize, mls);
return ZSTD_compressBlock_doubleFast(ms, seqStore, rep, src, srcSize);
/* Search Loop */
while (ip < ilimit) { /* < instead of <=, because (ip+1) */
@@ -653,6 +671,10 @@ static size_t ZSTD_compressBlock_doubleFast_extDict_generic(
return (size_t)(iend - anchor);
}
ZSTD_GEN_DFAST_FN(extDict, 4)
ZSTD_GEN_DFAST_FN(extDict, 5)
ZSTD_GEN_DFAST_FN(extDict, 6)
ZSTD_GEN_DFAST_FN(extDict, 7)
size_t ZSTD_compressBlock_doubleFast_extDict(
ZSTD_matchState_t* ms, seqStore_t* seqStore, U32 rep[ZSTD_REP_NUM],
@@ -663,12 +685,12 @@ size_t ZSTD_compressBlock_doubleFast_extDict(
{
default: /* includes case 3 */
case 4 :
return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 4);
return ZSTD_compressBlock_doubleFast_extDict_4(ms, seqStore, rep, src, srcSize);
case 5 :
return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 5);
return ZSTD_compressBlock_doubleFast_extDict_5(ms, seqStore, rep, src, srcSize);
case 6 :
return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 6);
return ZSTD_compressBlock_doubleFast_extDict_6(ms, seqStore, rep, src, srcSize);
case 7 :
return ZSTD_compressBlock_doubleFast_extDict_generic(ms, seqStore, rep, src, srcSize, 7);
return ZSTD_compressBlock_doubleFast_extDict_7(ms, seqStore, rep, src, srcSize);
}
}