diff --git a/lib/common/compiler.h b/lib/common/compiler.h index 6c7100e835a..42f289e0b4c 100644 --- a/lib/common/compiler.h +++ b/lib/common/compiler.h @@ -165,6 +165,12 @@ #define UNLIKELY(x) (x) #endif +#if __has_builtin(__builtin_unreachable) || (defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5))) +# define ZSTD_UNREACHABLE { assert(0), __builtin_unreachable(); } +#else +# define ZSTD_UNREACHABLE { assert(0); } +#endif + /* disable warnings */ #ifdef _MSC_VER /* Visual Studio */ # include /* For Visual 2005 */ diff --git a/lib/compress/zstd_lazy.c b/lib/compress/zstd_lazy.c index 3e2ee1dda01..2ee9cf63025 100644 --- a/lib/compress/zstd_lazy.c +++ b/lib/compress/zstd_lazy.c @@ -1317,14 +1317,10 @@ size_t ZSTD_RowFindBestMatch( } -typedef size_t (*searchMax_f)( - ZSTD_matchState_t* ms, - const BYTE* ip, const BYTE* iLimit, size_t* offsetPtr); - /** - * This struct contains the functions necessary for lazy to search. - * Currently, that is only searchMax. However, it is still valuable to have the - * VTable because this makes it easier to add more functions to the VTable later. + * Generate search functions templated on (dictMode, mls, rowLog). + * These functions are outlined for code size & compilation time. + * ZSTD_searchMax() dispatches to the correct implementation function. * * TODO: The start of the search function involves loading and calculating a * bunch of constants from the ZSTD_matchState_t. These computations could be @@ -1342,25 +1338,25 @@ typedef size_t (*searchMax_f)( * the single segment loop. It should go in searchMax instead of its own * function to avoid having multiple virtual function calls per search. */ -typedef struct { - searchMax_f searchMax; -} ZSTD_LazyVTable; -#define GEN_ZSTD_BT_VTABLE(dictMode, mls) \ - static size_t ZSTD_BtFindBestMatch_##dictMode##_##mls( \ - ZSTD_matchState_t* ms, \ - const BYTE* ip, const BYTE* const iLimit, \ - size_t* offBasePtr) \ - { \ - assert(MAX(4, MIN(6, ms->cParams.minMatch)) == mls); \ - return ZSTD_BtFindBestMatch(ms, ip, iLimit, offBasePtr, mls, ZSTD_##dictMode);\ - } \ - static const ZSTD_LazyVTable ZSTD_BtVTable_##dictMode##_##mls = { \ - ZSTD_BtFindBestMatch_##dictMode##_##mls \ - }; +#define ZSTD_BT_SEARCH_FN(dictMode, mls) ZSTD_BtFindBestMatch_##dictMode##_##mls +#define ZSTD_HC_SEARCH_FN(dictMode, mls) ZSTD_HcFindBestMatch_##dictMode##_##mls +#define ZSTD_ROW_SEARCH_FN(dictMode, mls, rowLog) ZSTD_RowFindBestMatch_##dictMode##_##mls##_##rowLog + +#define ZSTD_SEARCH_FN_ATTRS FORCE_NOINLINE + +#define GEN_ZSTD_BT_SEARCH_FN(dictMode, mls) \ + ZSTD_SEARCH_FN_ATTRS size_t ZSTD_BT_SEARCH_FN(dictMode, mls)( \ + ZSTD_matchState_t* ms, \ + const BYTE* ip, const BYTE* const iLimit, \ + size_t* offBasePtr) \ + { \ + assert(MAX(4, MIN(6, ms->cParams.minMatch)) == mls); \ + return ZSTD_BtFindBestMatch(ms, ip, iLimit, offBasePtr, mls, ZSTD_##dictMode); \ + } \ -#define GEN_ZSTD_HC_VTABLE(dictMode, mls) \ - static size_t ZSTD_HcFindBestMatch_##dictMode##_##mls( \ +#define GEN_ZSTD_HC_SEARCH_FN(dictMode, mls) \ + ZSTD_SEARCH_FN_ATTRS size_t ZSTD_HC_SEARCH_FN(dictMode, mls)( \ ZSTD_matchState_t* ms, \ const BYTE* ip, const BYTE* const iLimit, \ size_t* offsetPtr) \ @@ -1368,12 +1364,9 @@ typedef struct { assert(MAX(4, MIN(6, ms->cParams.minMatch)) == mls); \ return ZSTD_HcFindBestMatch(ms, ip, iLimit, offsetPtr, mls, ZSTD_##dictMode); \ } \ - static const ZSTD_LazyVTable ZSTD_HcVTable_##dictMode##_##mls = { \ - ZSTD_HcFindBestMatch_##dictMode##_##mls \ - }; -#define GEN_ZSTD_ROW_VTABLE(dictMode, mls, rowLog) \ - static size_t ZSTD_RowFindBestMatch_##dictMode##_##mls##_##rowLog( \ +#define GEN_ZSTD_ROW_SEARCH_FN(dictMode, mls, rowLog) \ + ZSTD_SEARCH_FN_ATTRS size_t ZSTD_ROW_SEARCH_FN(dictMode, mls, rowLog)( \ ZSTD_matchState_t* ms, \ const BYTE* ip, const BYTE* const iLimit, \ size_t* offsetPtr) \ @@ -1382,9 +1375,6 @@ typedef struct { assert(MAX(4, MIN(6, ms->cParams.searchLog)) == rowLog); \ return ZSTD_RowFindBestMatch(ms, ip, iLimit, offsetPtr, mls, ZSTD_##dictMode, rowLog); \ } \ - static const ZSTD_LazyVTable ZSTD_RowVTable_##dictMode##_##mls##_##rowLog = { \ - ZSTD_RowFindBestMatch_##dictMode##_##mls##_##rowLog \ - }; #define ZSTD_FOR_EACH_ROWLOG(X, dictMode, mls) \ X(dictMode, mls, 4) \ @@ -1407,84 +1397,103 @@ typedef struct { X(__VA_ARGS__, dictMatchState) \ X(__VA_ARGS__, dedicatedDictSearch) -/* Generate Row VTables for each combination of (dictMode, mls, rowLog) */ -ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS_ROWLOG, GEN_ZSTD_ROW_VTABLE) -/* Generate Binary Tree VTables for each combination of (dictMode, mls) */ -ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS, GEN_ZSTD_BT_VTABLE) -/* Generate Hash Chain VTables for each combination of (dictMode, mls) */ -ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS, GEN_ZSTD_HC_VTABLE) - -#define GEN_ZSTD_BT_VTABLE_ARRAY(dictMode) \ - { \ - &ZSTD_BtVTable_##dictMode##_4, \ - &ZSTD_BtVTable_##dictMode##_5, \ - &ZSTD_BtVTable_##dictMode##_6 \ - } - -#define GEN_ZSTD_HC_VTABLE_ARRAY(dictMode) \ - { \ - &ZSTD_HcVTable_##dictMode##_4, \ - &ZSTD_HcVTable_##dictMode##_5, \ - &ZSTD_HcVTable_##dictMode##_6 \ - } - -#define GEN_ZSTD_ROW_VTABLE_ARRAY_(dictMode, mls) \ - { \ - &ZSTD_RowVTable_##dictMode##_##mls##_4, \ - &ZSTD_RowVTable_##dictMode##_##mls##_5, \ - &ZSTD_RowVTable_##dictMode##_##mls##_6 \ - } +/* Generate row search fns for each combination of (dictMode, mls, rowLog) */ +ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS_ROWLOG, GEN_ZSTD_ROW_SEARCH_FN) +/* Generate binary Tree search fns for each combination of (dictMode, mls) */ +ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS, GEN_ZSTD_BT_SEARCH_FN) +/* Generate hash chain search fns for each combination of (dictMode, mls) */ +ZSTD_FOR_EACH_DICT_MODE(ZSTD_FOR_EACH_MLS, GEN_ZSTD_HC_SEARCH_FN) -#define GEN_ZSTD_ROW_VTABLE_ARRAY(dictMode) \ - { \ - GEN_ZSTD_ROW_VTABLE_ARRAY_(dictMode, 4), \ - GEN_ZSTD_ROW_VTABLE_ARRAY_(dictMode, 5), \ - GEN_ZSTD_ROW_VTABLE_ARRAY_(dictMode, 6) \ - } +typedef enum { search_hashChain=0, search_binaryTree=1, search_rowHash=2 } searchMethod_e; -#define GEN_ZSTD_VTABLE_ARRAY(X) \ - { \ - X(noDict), \ - X(extDict), \ - X(dictMatchState), \ - X(dedicatedDictSearch) \ +#define GEN_ZSTD_CALL_BT_SEARCH_FN(dictMode, mls) \ + case mls: \ + return ZSTD_BT_SEARCH_FN(dictMode, mls)(ms, ip, iend, offsetPtr); +#define GEN_ZSTD_CALL_HC_SEARCH_FN(dictMode, mls) \ + case mls: \ + return ZSTD_HC_SEARCH_FN(dictMode, mls)(ms, ip, iend, offsetPtr); +#define GEN_ZSTD_CALL_ROW_SEARCH_FN(dictMode, mls, rowLog) \ + case rowLog: \ + return ZSTD_ROW_SEARCH_FN(dictMode, mls, rowLog)(ms, ip, iend, offsetPtr); + +#define ZSTD_SWITCH_MLS(X, dictMode) \ + switch (mls) { \ + ZSTD_FOR_EACH_MLS(X, dictMode) \ } -/* ******************************* -* Common parser - lazy strategy -*********************************/ -typedef enum { search_hashChain=0, search_binaryTree=1, search_rowHash=2 } searchMethod_e; +#define ZSTD_SWITCH_ROWLOG(dictMode, mls) \ + case mls: \ + switch (rowLog) { \ + ZSTD_FOR_EACH_ROWLOG(GEN_ZSTD_CALL_ROW_SEARCH_FN, dictMode, mls) \ + } \ + ZSTD_UNREACHABLE; \ + break; + +#define ZSTD_SWITCH_SEARCH_METHOD(dictMode) \ + switch (searchMethod) { \ + case search_hashChain: \ + ZSTD_SWITCH_MLS(GEN_ZSTD_CALL_HC_SEARCH_FN, dictMode) \ + break; \ + case search_binaryTree: \ + ZSTD_SWITCH_MLS(GEN_ZSTD_CALL_BT_SEARCH_FN, dictMode) \ + break; \ + case search_rowHash: \ + ZSTD_SWITCH_MLS(ZSTD_SWITCH_ROWLOG, dictMode) \ + break; \ + } \ + ZSTD_UNREACHABLE; /** - * This table is indexed first by the four ZSTD_dictMode_e values, and then - * by the two searchMethod_e values. NULLs are placed for configurations - * that should never occur (extDict modes go to the other implementation - * below and there is no DDSS for binary tree search yet). + * Searches for the longest match at @p ip. + * Dispatches to the correct implementation function based on the + * (searchMethod, dictMode, mls, rowLog). We use switch statements + * here instead of using an indirect function call through a function + * pointer because after Spectre and Meltdown mitigations, indirect + * function calls can be very costly, especially in the kernel. + * + * NOTE: dictMode and searchMethod should be templated, so those switch + * statements should be optimized out. Only the mls & rowLog switches + * should be left. + * + * @param ms The match state. + * @param ip The position to search at. + * @param iend The end of the input data. + * @param[out] offsetPtr Stores the match offset into this pointer. + * @param mls The minimum search length, in the range [4, 6]. + * @param rowLog The row log (if applicable), in the range [4, 6]. + * @param searchMethod The search method to use (templated). + * @param dictMode The dictMode (templated). + * + * @returns The length of the longest match found, or < mls if no match is found. + * If a match is found its offset is stored in @p offsetPtr. */ - -static ZSTD_LazyVTable const* -ZSTD_selectLazyVTable(ZSTD_matchState_t const* ms, searchMethod_e searchMethod, ZSTD_dictMode_e dictMode) +FORCE_INLINE_TEMPLATE size_t ZSTD_searchMax( + ZSTD_matchState_t* ms, + const BYTE* ip, + const BYTE* iend, + size_t* offsetPtr, + U32 const mls, + U32 const rowLog, + searchMethod_e const searchMethod, + ZSTD_dictMode_e const dictMode) { - /* Fill the Hc/Bt VTable arrays with the right functions for the (dictMode, mls) combination. */ - ZSTD_LazyVTable const* const hcVTables[4][3] = GEN_ZSTD_VTABLE_ARRAY(GEN_ZSTD_HC_VTABLE_ARRAY); - ZSTD_LazyVTable const* const btVTables[4][3] = GEN_ZSTD_VTABLE_ARRAY(GEN_ZSTD_BT_VTABLE_ARRAY); - /* Fill the Row VTable array with the right functions for the (dictMode, mls, rowLog) combination. */ - ZSTD_LazyVTable const* const rowVTables[4][3][3] = GEN_ZSTD_VTABLE_ARRAY(GEN_ZSTD_ROW_VTABLE_ARRAY); - - U32 const mls = MAX(4, MIN(6, ms->cParams.minMatch)); - U32 const rowLog = MAX(4, MIN(6, ms->cParams.searchLog)); - switch (searchMethod) { - case search_hashChain: - return hcVTables[dictMode][mls - 4]; - case search_binaryTree: - return btVTables[dictMode][mls - 4]; - case search_rowHash: - return rowVTables[dictMode][mls - 4][rowLog - 4]; - default: - return NULL; + if (dictMode == ZSTD_noDict) { + ZSTD_SWITCH_SEARCH_METHOD(noDict) + } else if (dictMode == ZSTD_extDict) { + ZSTD_SWITCH_SEARCH_METHOD(extDict) + } else if (dictMode == ZSTD_dictMatchState) { + ZSTD_SWITCH_SEARCH_METHOD(dictMatchState) + } else if (dictMode == ZSTD_dedicatedDictSearch) { + ZSTD_SWITCH_SEARCH_METHOD(dedicatedDictSearch) } + ZSTD_UNREACHABLE; + return 0; } +/* ******************************* +* Common parser - lazy strategy +*********************************/ + FORCE_INLINE_TEMPLATE size_t ZSTD_compressBlock_lazy_generic( ZSTD_matchState_t* ms, seqStore_t* seqStore, @@ -1501,8 +1510,9 @@ ZSTD_compressBlock_lazy_generic( const BYTE* const base = ms->window.base; const U32 prefixLowestIndex = ms->window.dictLimit; const BYTE* const prefixLowest = base + prefixLowestIndex; + const U32 mls = BOUNDED(4, ms->cParams.minMatch, 6); + const U32 rowLog = BOUNDED(4, ms->cParams.searchLog, 6); - searchMax_f const searchMax = ZSTD_selectLazyVTable(ms, searchMethod, dictMode)->searchMax; U32 offset_1 = rep[0], offset_2 = rep[1]; U32 offsetSaved1 = 0, offsetSaved2 = 0; @@ -1519,8 +1529,6 @@ ZSTD_compressBlock_lazy_generic( 0; const U32 dictAndPrefixLength = (U32)((ip - prefixLowest) + (dictEnd - dictLowest)); - assert(searchMax != NULL); - DEBUGLOG(5, "ZSTD_compressBlock_lazy_generic (dictMode=%u) (searchFunc=%u)", (U32)dictMode, (U32)searchMethod); ip += (dictAndPrefixLength == 0); if (dictMode == ZSTD_noDict) { @@ -1538,7 +1546,6 @@ ZSTD_compressBlock_lazy_generic( } if (searchMethod == search_rowHash) { - const U32 rowLog = MAX(4, MIN(6, ms->cParams.searchLog)); ZSTD_row_fillHashCache(ms, base, rowLog, MIN(ms->cParams.minMatch, 6 /* mls caps out at 6 */), ms->nextToUpdate, ilimit); @@ -1579,7 +1586,7 @@ ZSTD_compressBlock_lazy_generic( /* first search (depth 0) */ { size_t offbaseFound = 999999999; - size_t const ml2 = searchMax(ms, ip, iend, &offbaseFound); + size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &offbaseFound, mls, rowLog, searchMethod, dictMode); if (ml2 > matchLength) matchLength = ml2, start = ip, offBase = offbaseFound; } @@ -1618,7 +1625,7 @@ ZSTD_compressBlock_lazy_generic( } } { size_t ofbCandidate=999999999; - size_t const ml2 = searchMax(ms, ip, iend, &ofbCandidate); + size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &ofbCandidate, mls, rowLog, searchMethod, dictMode); int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)ofbCandidate)); /* raw approx */ int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offBase) + 4); if ((ml2 >= 4) && (gain2 > gain1)) { @@ -1654,7 +1661,7 @@ ZSTD_compressBlock_lazy_generic( } } { size_t ofbCandidate=999999999; - size_t const ml2 = searchMax(ms, ip, iend, &ofbCandidate); + size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &ofbCandidate, mls, rowLog, searchMethod, dictMode); int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)ofbCandidate)); /* raw approx */ int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offBase) + 7); if ((ml2 >= 4) && (gain2 > gain1)) { @@ -1899,9 +1906,9 @@ size_t ZSTD_compressBlock_lazy_extDict_generic( const BYTE* const dictEnd = dictBase + dictLimit; const BYTE* const dictStart = dictBase + ms->window.lowLimit; const U32 windowLog = ms->cParams.windowLog; - const U32 rowLog = ms->cParams.searchLog < 5 ? 4 : 5; + const U32 mls = BOUNDED(4, ms->cParams.minMatch, 6); + const U32 rowLog = BOUNDED(4, ms->cParams.searchLog, 6); - searchMax_f const searchMax = ZSTD_selectLazyVTable(ms, searchMethod, ZSTD_extDict)->searchMax; U32 offset_1 = rep[0], offset_2 = rep[1]; DEBUGLOG(5, "ZSTD_compressBlock_lazy_extDict_generic (searchFunc=%u)", (U32)searchMethod); @@ -1943,7 +1950,7 @@ size_t ZSTD_compressBlock_lazy_extDict_generic( /* first search (depth 0) */ { size_t ofbCandidate = 999999999; - size_t const ml2 = searchMax(ms, ip, iend, &ofbCandidate); + size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &ofbCandidate, mls, rowLog, searchMethod, ZSTD_extDict); if (ml2 > matchLength) matchLength = ml2, start = ip, offBase = ofbCandidate; } @@ -1978,7 +1985,7 @@ size_t ZSTD_compressBlock_lazy_extDict_generic( /* search match, depth 1 */ { size_t ofbCandidate = 999999999; - size_t const ml2 = searchMax(ms, ip, iend, &ofbCandidate); + size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &ofbCandidate, mls, rowLog, searchMethod, ZSTD_extDict); int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)ofbCandidate)); /* raw approx */ int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offBase) + 4); if ((ml2 >= 4) && (gain2 > gain1)) { @@ -2010,7 +2017,7 @@ size_t ZSTD_compressBlock_lazy_extDict_generic( /* search match, depth 2 */ { size_t ofbCandidate = 999999999; - size_t const ml2 = searchMax(ms, ip, iend, &ofbCandidate); + size_t const ml2 = ZSTD_searchMax(ms, ip, iend, &ofbCandidate, mls, rowLog, searchMethod, ZSTD_extDict); int const gain2 = (int)(ml2*4 - ZSTD_highbit32((U32)ofbCandidate)); /* raw approx */ int const gain1 = (int)(matchLength*4 - ZSTD_highbit32((U32)offBase) + 7); if ((ml2 >= 4) && (gain2 > gain1)) {