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[huf] Reduce stack usage of HUF_readDTableX2 by ~460 bytes 

* Use `HUF_readStats_wksp()`
* Use workspace in `HUF_fillDTableX2*()`
* Clean up workspace usage to use a workspace struct
dev
Nick Terrell 2021-03-05 12:36:50 -08:00
parent b5fd348a85
commit 0f18059a4e
1 changed files with 41 additions and 40 deletions
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81
lib/decompress/huf_decompress.c
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@ -528,13 +528,15 @@ typedef rankValCol_t rankVal_t[HUF_TABLELOG_MAX];
static void HUF_fillDTableX2Level2(HUF_DEltX2* DTable, U32 sizeLog, const U32 consumed,
const U32* rankValOrigin, const int minWeight,
const sortedSymbol_t* sortedSymbols, const U32 sortedListSize,
U32 nbBitsBaseline, U16 baseSeq)
U32 nbBitsBaseline, U16 baseSeq, U32* wksp, size_t wkspSize)
{
HUF_DEltX2 DElt;
U32 rankVal[HUF_TABLELOG_MAX + 1];
U32* rankVal = wksp;
assert(wkspSize >= HUF_TABLELOG_MAX + 1);
(void)wkspSize;
/* get pre-calculated rankVal */
ZSTD_memcpy(rankVal, rankValOrigin, sizeof(rankVal));
ZSTD_memcpy(rankVal, rankValOrigin, sizeof(U32) * (HUF_TABLELOG_MAX + 1));
/* fill skipped values */
if (minWeight>1) {
@ -569,14 +571,18 @@ static void HUF_fillDTableX2Level2(HUF_DEltX2* DTable, U32 sizeLog, const U32 co
static void HUF_fillDTableX2(HUF_DEltX2* DTable, const U32 targetLog,
const sortedSymbol_t* sortedList, const U32 sortedListSize,
const U32* rankStart, rankVal_t rankValOrigin, const U32 maxWeight,
const U32 nbBitsBaseline)
const U32 nbBitsBaseline, U32* wksp, size_t wkspSize)
{
U32 rankVal[HUF_TABLELOG_MAX + 1];
U32* rankVal = wksp;
const int scaleLog = nbBitsBaseline - targetLog; /* note : targetLog >= srcLog, hence scaleLog <= 1 */
const U32 minBits = nbBitsBaseline - maxWeight;
U32 s;
ZSTD_memcpy(rankVal, rankValOrigin, sizeof(rankVal));
assert(wkspSize >= HUF_TABLELOG_MAX + 1);
wksp += HUF_TABLELOG_MAX + 1;
wkspSize -= HUF_TABLELOG_MAX + 1;
ZSTD_memcpy(rankVal, rankValOrigin, sizeof(U32) * (HUF_TABLELOG_MAX + 1));
/* fill DTable */
for (s=0; s<sortedListSize; s++) {
@ -594,7 +600,7 @@ static void HUF_fillDTableX2(HUF_DEltX2* DTable, const U32 targetLog,
HUF_fillDTableX2Level2(DTable+start, targetLog-nbBits, nbBits,
rankValOrigin[nbBits], minWeight,
sortedList+sortedRank, sortedListSize-sortedRank,
nbBitsBaseline, symbol);
nbBitsBaseline, symbol, wksp, wkspSize);
} else {
HUF_DEltX2 DElt;
MEM_writeLE16(&(DElt.sequence), symbol);
@ -608,6 +614,15 @@ static void HUF_fillDTableX2(HUF_DEltX2* DTable, const U32 targetLog,
}
}
typedef struct {
rankValCol_t rankVal[HUF_TABLELOG_MAX];
U32 rankStats[HUF_TABLELOG_MAX + 1];
U32 rankStart0[HUF_TABLELOG_MAX + 2];
sortedSymbol_t sortedSymbol[HUF_SYMBOLVALUE_MAX + 1];
BYTE weightList[HUF_SYMBOLVALUE_MAX + 1];
U32 wksp[HUF_READ_STATS_WORKSPACE_SIZE_U32];
} HUF_ReadDTableX2_Workspace;
size_t HUF_readDTableX2_wksp(HUF_DTable* DTable,
const void* src, size_t srcSize,
void* workSpace, size_t wkspSize)
@ -620,47 +635,32 @@ size_t HUF_readDTableX2_wksp(HUF_DTable* DTable,
HUF_DEltX2* const dt = (HUF_DEltX2*)dtPtr;
U32 *rankStart;
rankValCol_t* rankVal;
U32* rankStats;
U32* rankStart0;
sortedSymbol_t* sortedSymbol;
BYTE* weightList;
size_t spaceUsed32 = 0;
HUF_ReadDTableX2_Workspace* wksp = (HUF_ReadDTableX2_Workspace*)workSpace;
rankVal = (rankValCol_t *)((U32 *)workSpace + spaceUsed32);
spaceUsed32 += (sizeof(rankValCol_t) * HUF_TABLELOG_MAX) >> 2;
rankStats = (U32 *)workSpace + spaceUsed32;
spaceUsed32 += HUF_TABLELOG_MAX + 1;
rankStart0 = (U32 *)workSpace + spaceUsed32;
spaceUsed32 += HUF_TABLELOG_MAX + 2;
sortedSymbol = (sortedSymbol_t *)workSpace + (spaceUsed32 * sizeof(U32)) / sizeof(sortedSymbol_t);
spaceUsed32 += HUF_ALIGN(sizeof(sortedSymbol_t) * (HUF_SYMBOLVALUE_MAX + 1), sizeof(U32)) >> 2;
weightList = (BYTE *)((U32 *)workSpace + spaceUsed32);
spaceUsed32 += HUF_ALIGN(HUF_SYMBOLVALUE_MAX + 1, sizeof(U32)) >> 2;
if (sizeof(*wksp) > wkspSize) return ERROR(tableLog_tooLarge);
if ((spaceUsed32 << 2) > wkspSize) return ERROR(tableLog_tooLarge);
rankStart = rankStart0 + 1;
ZSTD_memset(rankStats, 0, sizeof(U32) * (2 * HUF_TABLELOG_MAX + 2 + 1));
rankStart = wksp->rankStart0 + 1;
ZSTD_memset(wksp->rankStats, 0, sizeof(wksp->rankStats));
ZSTD_memset(wksp->rankStart0, 0, sizeof(wksp->rankStart0));
DEBUG_STATIC_ASSERT(sizeof(HUF_DEltX2) == sizeof(HUF_DTable)); /* if compiler fails here, assertion is wrong */
if (maxTableLog > HUF_TABLELOG_MAX) return ERROR(tableLog_tooLarge);
/* ZSTD_memset(weightList, 0, sizeof(weightList)); */ /* is not necessary, even though some analyzer complain ... */
iSize = HUF_readStats(weightList, HUF_SYMBOLVALUE_MAX + 1, rankStats, &nbSymbols, &tableLog, src, srcSize);
iSize = HUF_readStats_wksp(wksp->weightList, HUF_SYMBOLVALUE_MAX + 1, wksp->rankStats, &nbSymbols, &tableLog, src, srcSize, wksp->wksp, sizeof(wksp->wksp), /* bmi2 */ 0);
if (HUF_isError(iSize)) return iSize;
/* check result */
if (tableLog > maxTableLog) return ERROR(tableLog_tooLarge); /* DTable can't fit code depth */
/* find maxWeight */
for (maxW = tableLog; rankStats[maxW]==0; maxW--) {} /* necessarily finds a solution before 0 */
for (maxW = tableLog; wksp->rankStats[maxW]==0; maxW--) {} /* necessarily finds a solution before 0 */
/* Get start index of each weight */
{ U32 w, nextRankStart = 0;
for (w=1; w<maxW+1; w++) {
U32 curr = nextRankStart;
nextRankStart += rankStats[w];
nextRankStart += wksp->rankStats[w];
rankStart[w] = curr;
}
rankStart[0] = nextRankStart; /* put all 0w symbols at the end of sorted list*/
@ -670,37 +670,38 @@ size_t HUF_readDTableX2_wksp(HUF_DTable* DTable,
/* sort symbols by weight */
{ U32 s;
for (s=0; s<nbSymbols; s++) {
U32 const w = weightList[s];
U32 const w = wksp->weightList[s];
U32 const r = rankStart[w]++;
sortedSymbol[r].symbol = (BYTE)s;
sortedSymbol[r].weight = (BYTE)w;
wksp->sortedSymbol[r].symbol = (BYTE)s;
wksp->sortedSymbol[r].weight = (BYTE)w;
}
rankStart[0] = 0; /* forget 0w symbols; this is beginning of weight(1) */
}
/* Build rankVal */
{ U32* const rankVal0 = rankVal[0];
{ U32* const rankVal0 = wksp->rankVal[0];
{ int const rescale = (maxTableLog-tableLog) - 1; /* tableLog <= maxTableLog */
U32 nextRankVal = 0;
U32 w;
for (w=1; w<maxW+1; w++) {
U32 curr = nextRankVal;
nextRankVal += rankStats[w] << (w+rescale);
nextRankVal += wksp->rankStats[w] << (w+rescale);
rankVal0[w] = curr;
} }
{ U32 const minBits = tableLog+1 - maxW;
U32 consumed;
for (consumed = minBits; consumed < maxTableLog - minBits + 1; consumed++) {
U32* const rankValPtr = rankVal[consumed];
U32* const rankValPtr = wksp->rankVal[consumed];
U32 w;
for (w = 1; w < maxW+1; w++) {
rankValPtr[w] = rankVal0[w] >> consumed;
} } } }
HUF_fillDTableX2(dt, maxTableLog,
sortedSymbol, sizeOfSort,
rankStart0, rankVal, maxW,
tableLog+1);
wksp->sortedSymbol, sizeOfSort,
wksp->rankStart0, wksp->rankVal, maxW,
tableLog+1,
wksp->wksp, sizeof(wksp->wksp) / sizeof(U32));
dtd.tableLog = (BYTE)maxTableLog;
dtd.tableType = 1;
@ -1225,7 +1226,7 @@ size_t HUF_decompress1X1 (void* dst, size_t dstSize, const void* cSrc, size_t cS
HUF_CREATE_STATIC_DTABLEX1(DTable, HUF_TABLELOG_MAX);
return HUF_decompress1X1_DCtx (DTable, dst, dstSize, cSrc, cSrcSize);
}
#endif
#endif
#ifndef HUF_FORCE_DECOMPRESS_X1
size_t HUF_readDTableX2(HUF_DTable* DTable, const void* src, size_t srcSize)