commit 10b8c99bbbb5405f5fb37513645421b8e3c3ba43
parent bdc751ce2346e95f96de3d55d48ddb25674073c5
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Thu, 30 Nov 2017 11:28:51 -0200
small peephole optimizations
Diffstat:
5 files changed, 63 insertions(+), 48 deletions(-)
diff --git a/lcode.c b/lcode.c
@@ -1,5 +1,5 @@
/*
-** $Id: lcode.c,v 2.138 2017/11/28 15:26:15 roberto Exp roberto $
+** $Id: lcode.c,v 2.140 2017/11/30 13:17:06 roberto Exp roberto $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@@ -134,17 +134,10 @@ void luaK_concat (FuncState *fs, int *l1, int l2) {
/*
** Create a jump instruction and return its position, so its destination
-** can be fixed later (with 'fixjump'). If there are jumps to
-** this position (kept in 'jpc'), link them all together so that
-** 'patchlistaux' will fix all them directly to the final destination.
+** can be fixed later (with 'fixjump').
*/
int luaK_jump (FuncState *fs) {
- int jpc = fs->jpc; /* save list of jumps to here */
- int j;
- fs->jpc = NO_JUMP; /* no more jumps to here */
- j = codesJ(fs, OP_JMP, NO_JUMP, 0);
- luaK_concat(fs, &j, jpc); /* keep them on hold */
- return j;
+ return codesJ(fs, OP_JMP, NO_JUMP, 0);
}
@@ -250,38 +243,19 @@ static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,
/*
-** Ensure all pending jumps to current position are fixed (jumping
-** to current position with no values) and reset list of pending
-** jumps
-*/
-static void dischargejpc (FuncState *fs) {
- patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc);
- fs->jpc = NO_JUMP;
-}
-
-
-/*
-** Add elements in 'list' to list of pending jumps to "here"
-** (current position)
-*/
-void luaK_patchtohere (FuncState *fs, int list) {
- luaK_getlabel(fs); /* mark "here" as a jump target */
- luaK_concat(fs, &fs->jpc, list);
-}
-
-
-/*
** Path all jumps in 'list' to jump to 'target'.
** (The assert means that we cannot fix a jump to a forward address
** because we only know addresses once code is generated.)
*/
void luaK_patchlist (FuncState *fs, int list, int target) {
- if (target == fs->pc) /* 'target' is current position? */
- luaK_patchtohere(fs, list); /* add list to pending jumps */
- else {
- lua_assert(target < fs->pc);
- patchlistaux(fs, list, target, NO_REG, target);
- }
+ lua_assert(target <= fs->pc);
+ patchlistaux(fs, list, target, NO_REG, target);
+}
+
+
+void luaK_patchtohere (FuncState *fs, int list) {
+ int hr = luaK_getlabel(fs); /* mark "here" as a jump target */
+ luaK_patchlist(fs, list, hr);
}
@@ -365,7 +339,6 @@ static void savelineinfo (FuncState *fs, Proto *f, int pc, int line) {
*/
static int luaK_code (FuncState *fs, Instruction i) {
Proto *f = fs->f;
- dischargejpc(fs); /* 'pc' will change */
/* put new instruction in code array */
luaM_growvector(fs->ls->L, f->code, fs->pc, f->sizecode, Instruction,
MAX_INT, "opcodes");
@@ -1537,3 +1510,45 @@ void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) {
fs->freereg = base + 1; /* free registers with list values */
}
+
+/*
+** return the final target of a jump (skipping jumps to jumps)
+*/
+static int finaltarget (Instruction *code, int i) {
+ int count;
+ for (count = 0; count < 100; count++) { /* avoid infinite loops */
+ Instruction pc = code[i];
+ if (GET_OPCODE(pc) != OP_JMP)
+ break;
+ else
+ i += GETARG_sJ(pc) + 1;
+ }
+ return i;
+}
+
+
+/*
+** Do a final pass over the code of a function, doing small peephole
+** optimizations and adjustments.
+*/
+void luaK_finish (FuncState *fs) {
+ int i;
+ Proto *p = fs->f;
+ for (i = 0; i < fs->pc; i++) {
+ Instruction *pc = &p->code[i];
+ switch (GET_OPCODE(*pc)) {
+ case OP_RETURN: case OP_RETURN0: case OP_RETURN1:
+ case OP_TAILCALL: {
+ if (p->sizep > 0)
+ SETARG_k(*pc, 1); /* signal that they must close upvalues */
+ break;
+ }
+ case OP_JMP: {
+ int target = finaltarget(p->code, i);
+ fixjump(fs, i, target);
+ break;
+ }
+ default: break;
+ }
+ }
+}
diff --git a/lcode.h b/lcode.h
@@ -1,5 +1,5 @@
/*
-** $Id: lcode.h,v 1.67 2017/09/28 16:53:29 roberto Exp roberto $
+** $Id: lcode.h,v 1.68 2017/10/04 21:56:32 roberto Exp roberto $
** Code generator for Lua
** See Copyright Notice in lua.h
*/
@@ -88,6 +88,7 @@ LUAI_FUNC void luaK_infix (FuncState *fs, BinOpr op, expdesc *v);
LUAI_FUNC void luaK_posfix (FuncState *fs, BinOpr op, expdesc *v1,
expdesc *v2, int line);
LUAI_FUNC void luaK_setlist (FuncState *fs, int base, int nelems, int tostore);
+LUAI_FUNC void luaK_finish (FuncState *fs);
#endif
diff --git a/lparser.c b/lparser.c
@@ -1,5 +1,5 @@
/*
-** $Id: lparser.c,v 2.167 2017/10/04 21:53:03 roberto Exp roberto $
+** $Id: lparser.c,v 2.168 2017/11/23 16:35:54 roberto Exp roberto $
** Lua Parser
** See Copyright Notice in lua.h
*/
@@ -547,7 +547,6 @@ static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) {
fs->previousline = f->linedefined;
fs->iwthabs = 0;
fs->lasttarget = 0;
- fs->jpc = NO_JUMP;
fs->freereg = 0;
fs->nk = 0;
fs->nabslineinfo = 0;
@@ -569,6 +568,7 @@ static void close_func (LexState *ls) {
Proto *f = fs->f;
luaK_ret(fs, 0, 0); /* final return */
leaveblock(fs);
+ luaK_finish(fs);
luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
f->sizecode = fs->pc;
luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, ls_byte);
diff --git a/lparser.h b/lparser.h
@@ -1,5 +1,5 @@
/*
-** $Id: lparser.h,v 1.77 2017/04/28 20:57:45 roberto Exp roberto $
+** $Id: lparser.h,v 1.78 2017/06/27 11:35:31 roberto Exp roberto $
** Lua Parser
** See Copyright Notice in lua.h
*/
@@ -124,7 +124,6 @@ typedef struct FuncState {
int pc; /* next position to code (equivalent to 'ncode') */
int lasttarget; /* 'label' of last 'jump label' */
int previousline; /* last line that was saved in 'lineinfo' */
- int jpc; /* list of pending jumps to 'pc' */
int nk; /* number of elements in 'k' */
int np; /* number of elements in 'p' */
int nabslineinfo; /* number of elements in 'abslineinfo' */
diff --git a/lvm.c b/lvm.c
@@ -1,5 +1,5 @@
/*
-** $Id: lvm.c,v 2.321 2017/11/29 13:02:17 roberto Exp roberto $
+** $Id: lvm.c,v 2.322 2017/11/29 16:57:36 roberto Exp roberto $
** Lua virtual machine
** See Copyright Notice in lua.h
*/
@@ -1453,7 +1453,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
/* next instruction will do the return */
}
else { /* tail call */
- if (cl->p->sizep > 0) /* close upvalues from previous call */
+ if (TESTARG_k(i)) /* close upvalues from previous call */
luaF_close(L, ci->func + 1);
luaD_pretailcall(L, ci, ra, b); /* prepare call frame */
goto tailcall;
@@ -1462,7 +1462,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
}
vmcase(OP_RETURN) {
int b = GETARG_B(i);
- if (cl->p->sizep > 0)
+ if (TESTARG_k(i))
luaF_close(L, base);
halfProtect(
luaD_poscall(L, ci, ra, (b != 0 ? b - 1 : cast_int(L->top - ra)))
@@ -1470,7 +1470,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
return;
}
vmcase(OP_RETURN0) {
- if (cl->p->sizep > 0)
+ if (TESTARG_k(i))
luaF_close(L, base);
if (L->hookmask)
halfProtect(luaD_poscall(L, ci, ra, 0)); /* no hurry... */
@@ -1484,7 +1484,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
return;
}
vmcase(OP_RETURN1) {
- if (cl->p->sizep > 0)
+ if (TESTARG_k(i))
luaF_close(L, base);
if (L->hookmask)
halfProtect(luaD_poscall(L, ci, ra, 1)); /* no hurry... */
