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TOYWASM_USE_LOCALS_FAST_PATH
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@yamt
yamt committed Aug 5, 2023
1 parent 8d4be24 commit 6abbb8b
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Showing 5 changed files with 79 additions and 51 deletions.
66 changes: 34 additions & 32 deletions lib/cell.c
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Original file line number Diff line number Diff line change
Expand Up @@ -59,13 +59,7 @@ static uint32_t
localcellidx_lookup(const struct localcellidx *lci, uint32_t idx,
uint32_t *cszp)
{
const uint16_t *p = &lci->cellidxes[idx];
uint16_t cidx = *p;
if (cszp != NULL) {
uint16_t next_cidx = p[1];
*cszp = next_cidx - cidx;
}
return cidx;
return cellidx_lookup(lci->cellidxes, idx, cszp);
}
#endif

Expand Down Expand Up @@ -158,66 +152,74 @@ localtype_cellsize(const struct localtype *lt)
return localtype_cellidx(lt, lt->nlocals, NULL);
}

/*
* frame_locals_cellidx: calculate the index and size of a local
* for the given localidx
*
* as this is called on every `local.get`, it is one of
* the most performance critical code in the interpreter.
*/
uint32_t
#if defined(TOYWASM_USE_SMALL_CELLS)
static uint32_t
frame_locals_cellidx_slow(struct exec_context *ctx, uint32_t localidx,
uint32_t *cszp)
{
xassert(cszp != NULL);
#if defined(TOYWASM_USE_SMALL_CELLS)
struct local_info_slow *slow = &ctx->local_u.slow;
uint32_t cidx;
uint32_t nparams = ctx->nparams;
uint32_t nparams = slow->paramtype->ntypes;
if (localidx < nparams) {
cidx = resulttype_cellidx(ctx->paramtype, localidx, cszp);
cidx = resulttype_cellidx(slow->paramtype, localidx, cszp);
} else {
assert(localidx < nparams + ctx->localtype->nlocals);
cidx = ctx->paramcsz;
cidx += localtype_cellidx(ctx->localtype, localidx - nparams,
assert(localidx < nparams + slow->localtype->nlocals);
cidx = resulttype_cellsize(slow->paramtype);
cidx += localtype_cellidx(slow->localtype, localidx - nparams,
cszp);
}
return cidx;
#else
*cszp = 1;
return localidx;
#endif
}

uint32_t
#if defined(TOYWASM_USE_LOCALS_FAST_PATH)
static uint32_t
frame_locals_cellidx_fast(struct exec_context *ctx, uint32_t localidx,
uint32_t *cszp)
{
xassert(cszp != NULL);
xassert(ctx->paramtype_cellidxes != NULL);
xassert(ctx->localtype_cellidxes != NULL);
const struct local_info_fast *fast = &ctx->local_u.fast;
xassert(fast->paramtype_cellidxes != NULL);
xassert(fast->localtype_cellidxes != NULL);
uint32_t cidx;
uint32_t nparams = ctx->nparams;
uint32_t nparams = fast->nparams;
if (localidx < nparams) {
cidx = cellidx_lookup(ctx->paramtype_cellidxes, localidx,
cidx = cellidx_lookup(fast->paramtype_cellidxes, localidx,
cszp);
} else {
assert(localidx < nparams + ctx->localtype->nlocals);
cidx = ctx->paramcsz;
cidx += cellidx_lookup(ctx->localtype_cellidxes,
cidx = fast->paramcsz;
cidx += cellidx_lookup(fast->localtype_cellidxes,
localidx - nparams, cszp);
}
return cidx;
}
#endif
#endif /* defined(TOYWASM_USE_SMALL_CELLS) */

/*
* frame_locals_cellidx: calculate the index and size of a local
* for the given localidx
*
* as this is called on every `local.get`, it is one of
* the most performance critical code in the interpreter.
*/
uint32_t
frame_locals_cellidx(struct exec_context *ctx, uint32_t localidx,
uint32_t *cszp)
{
xassert(cszp != NULL);
#if defined(TOYWASM_USE_SMALL_CELLS)
#if defined(TOYWASM_USE_LOCALS_FAST_PATH)
if (__predict_true(ctx->fast)) {
return frame_locals_cellidx_fast(ctx, localidx, cszp);
}
#endif
return frame_locals_cellidx_slow(ctx, localidx, cszp);
#else /* defined(TOYWASM_USE_SMALL_CELLS) */
*cszp = 1;
return localidx;
#endif /* defined(TOYWASM_USE_SMALL_CELLS) */
}

void
Expand Down
40 changes: 27 additions & 13 deletions lib/exec.c
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Original file line number Diff line number Diff line change
Expand Up @@ -256,29 +256,43 @@ set_current_frame(struct exec_context *ctx, const struct funcframe *frame,
*
* Note: such exprs do never have function calls.
* (thus ei != NULL)
*
* Note: such exprs do never have parameters or locals.
* (thus no need to set ctx->fast or ctx->local_u)
*/
assert(ei != NULL);
ctx->paramtype = NULL;
ctx->localtype = NULL;
ctx->nparams = 0;
ctx->paramcsz = 0;
ctx->fast = false;
ctx->ei = ei;
} else {
const struct module *m = inst->module;
const struct functype *ft = module_functype(m, funcidx);
const struct func *func =
&m->funcs[funcidx - m->nimportedfuncs];
ctx->paramtype = &ft->parameter;
assert(frame->nresults == resulttype_cellsize(&ft->result));
ctx->localtype = &func->localtype;
assert(ei == NULL || ei == &func->e.ei);
ctx->nparams = ft->parameter.ntypes;
ctx->paramcsz = resulttype_cellsize(&ft->parameter);
ctx->fast = ctx->paramtype->cellidx.cellidxes != NULL &&
ctx->localtype->cellidx.cellidxes != NULL;
ctx->paramtype_cellidxes = ctx->paramtype->cellidx.cellidxes;
ctx->localtype_cellidxes = ctx->localtype->cellidx.cellidxes;
#if defined(TOYWASM_USE_LOCALS_FAST_PATH)
const uint16_t *paramtype_cellidxes =
ft->parameter.cellidx.cellidxes;
const uint16_t *localtype_cellidxes =
func->localtype.cellidx.cellidxes;
/*
* if we have both of indexes, use the fast path.
*/
ctx->fast = paramtype_cellidxes != NULL &&
localtype_cellidxes != NULL;
if (ctx->fast) {
struct local_info_fast *fast = &ctx->local_u.fast;
fast->nparams = ft->parameter.ntypes;
fast->paramcsz = resulttype_cellsize(&ft->parameter);
fast->paramtype_cellidxes = paramtype_cellidxes;
fast->localtype_cellidxes = localtype_cellidxes;
} else {
#endif
struct local_info_slow *slow = &ctx->local_u.slow;
slow->paramtype = &ft->parameter;
slow->localtype = &func->localtype;
#if defined(TOYWASM_USE_LOCALS_FAST_PATH)
}
#endif
ctx->ei = &func->e.ei;
}
#if defined(TOYWASM_USE_LOCALS_CACHE)
Expand Down
22 changes: 16 additions & 6 deletions lib/exec_context.h
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Original file line number Diff line number Diff line change
Expand Up @@ -146,14 +146,24 @@ struct context;
struct exec_context {
/* Some cached info about the current frame. */
struct instance *instance;
const struct resulttype *paramtype;
const struct localtype *localtype;
const struct expr_exec_info *ei;
uint32_t nparams;
uint32_t paramcsz;
const uint16_t *paramtype_cellidxes;
const uint16_t *localtype_cellidxes;
#if defined(TOYWASM_USE_LOCALS_FAST_PATH)
bool fast;
#endif
union {
#if defined(TOYWASM_USE_LOCALS_FAST_PATH)
struct local_info_fast {
const uint16_t *paramtype_cellidxes;
const uint16_t *localtype_cellidxes;
uint32_t nparams;
uint32_t paramcsz;
} fast;
#endif
struct local_info_slow {
const struct resulttype *paramtype;
const struct localtype *localtype;
} slow;
} local_u;

/* The instruction pointer */
const uint8_t *p;
Expand Down
1 change: 1 addition & 0 deletions lib/toywasm_config.c.in
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@ const char *const toywasm_config_string =
"\tTOYWASM_USE_JUMP_BINARY_SEARCH = @TOYWASM_USE_JUMP_BINARY_SEARCH@\n"
"\tTOYWASM_USE_JUMP_CACHE = @TOYWASM_USE_JUMP_CACHE@\n"
"\tTOYWASM_JUMP_CACHE2_SIZE = @TOYWASM_JUMP_CACHE2_SIZE@\n"
"\tTOYWASM_USE_LOCALS_FAST_PATH = @TOYWASM_USE_LOCALS_FAST_PATH@\n"
"\tTOYWASM_USE_LOCALS_CACHE = @TOYWASM_USE_LOCALS_CACHE@\n"
"\tTOYWASM_USE_SEPARATE_LOCALS = @TOYWASM_USE_SEPARATE_LOCALS@\n"
"\tTOYWASM_USE_SMALL_CELLS = @TOYWASM_USE_SMALL_CELLS@\n"
Expand Down
1 change: 1 addition & 0 deletions lib/toywasm_config.h.in
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@
#cmakedefine TOYWASM_USE_JUMP_BINARY_SEARCH
#cmakedefine TOYWASM_USE_JUMP_CACHE
#define TOYWASM_JUMP_CACHE2_SIZE @TOYWASM_JUMP_CACHE2_SIZE@
#cmakedefine TOYWASM_USE_LOCALS_FAST_PATH
#cmakedefine TOYWASM_USE_LOCALS_CACHE
#cmakedefine TOYWASM_USE_SEPARATE_LOCALS
#cmakedefine TOYWASM_USE_SMALL_CELLS
Expand Down

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