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https://github.com/lua/lua
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small peephole optimizations
This commit is contained in:
Roberto Ierusalimschy
parent
bdc751ce23
commit
10b8c99bbb
91
lcode.c
91
lcode.c
@ -1,5 +1,5 @@
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/*
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** $Id: lcode.c,v 2.138 2017/11/28 15:26:15 roberto Exp roberto $
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** $Id: lcode.c,v 2.140 2017/11/30 13:17:06 roberto Exp roberto $
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** Code generator for Lua
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** See Copyright Notice in lua.h
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*/
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@ -134,17 +134,10 @@ void luaK_concat (FuncState *fs, int *l1, int l2) {
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/*
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** Create a jump instruction and return its position, so its destination
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** can be fixed later (with 'fixjump'). If there are jumps to
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** this position (kept in 'jpc'), link them all together so that
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** 'patchlistaux' will fix all them directly to the final destination.
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** can be fixed later (with 'fixjump').
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*/
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int luaK_jump (FuncState *fs) {
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int jpc = fs->jpc; /* save list of jumps to here */
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int j;
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fs->jpc = NO_JUMP; /* no more jumps to here */
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j = codesJ(fs, OP_JMP, NO_JUMP, 0);
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luaK_concat(fs, &j, jpc); /* keep them on hold */
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return j;
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return codesJ(fs, OP_JMP, NO_JUMP, 0);
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}
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@ -249,39 +242,20 @@ static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,
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}
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/*
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** Ensure all pending jumps to current position are fixed (jumping
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** to current position with no values) and reset list of pending
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** jumps
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*/
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static void dischargejpc (FuncState *fs) {
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patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc);
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fs->jpc = NO_JUMP;
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}
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/*
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** Add elements in 'list' to list of pending jumps to "here"
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** (current position)
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*/
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void luaK_patchtohere (FuncState *fs, int list) {
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luaK_getlabel(fs); /* mark "here" as a jump target */
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luaK_concat(fs, &fs->jpc, list);
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}
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/*
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** Path all jumps in 'list' to jump to 'target'.
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** (The assert means that we cannot fix a jump to a forward address
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** because we only know addresses once code is generated.)
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*/
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void luaK_patchlist (FuncState *fs, int list, int target) {
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if (target == fs->pc) /* 'target' is current position? */
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luaK_patchtohere(fs, list); /* add list to pending jumps */
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else {
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lua_assert(target < fs->pc);
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patchlistaux(fs, list, target, NO_REG, target);
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}
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lua_assert(target <= fs->pc);
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patchlistaux(fs, list, target, NO_REG, target);
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}
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void luaK_patchtohere (FuncState *fs, int list) {
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int hr = luaK_getlabel(fs); /* mark "here" as a jump target */
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luaK_patchlist(fs, list, hr);
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}
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@ -365,7 +339,6 @@ static void savelineinfo (FuncState *fs, Proto *f, int pc, int line) {
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*/
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static int luaK_code (FuncState *fs, Instruction i) {
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Proto *f = fs->f;
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dischargejpc(fs); /* 'pc' will change */
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/* put new instruction in code array */
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luaM_growvector(fs->ls->L, f->code, fs->pc, f->sizecode, Instruction,
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MAX_INT, "opcodes");
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@ -1537,3 +1510,45 @@ void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) {
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fs->freereg = base + 1; /* free registers with list values */
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}
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/*
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** return the final target of a jump (skipping jumps to jumps)
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*/
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static int finaltarget (Instruction *code, int i) {
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int count;
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for (count = 0; count < 100; count++) { /* avoid infinite loops */
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Instruction pc = code[i];
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if (GET_OPCODE(pc) != OP_JMP)
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break;
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else
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i += GETARG_sJ(pc) + 1;
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}
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return i;
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}
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/*
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** Do a final pass over the code of a function, doing small peephole
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** optimizations and adjustments.
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*/
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void luaK_finish (FuncState *fs) {
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int i;
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Proto *p = fs->f;
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for (i = 0; i < fs->pc; i++) {
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Instruction *pc = &p->code[i];
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switch (GET_OPCODE(*pc)) {
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case OP_RETURN: case OP_RETURN0: case OP_RETURN1:
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case OP_TAILCALL: {
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if (p->sizep > 0)
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SETARG_k(*pc, 1); /* signal that they must close upvalues */
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break;
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}
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case OP_JMP: {
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int target = finaltarget(p->code, i);
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fixjump(fs, i, target);
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break;
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}
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default: break;
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}
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}
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}
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3
lcode.h
3
lcode.h
@ -1,5 +1,5 @@
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/*
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** $Id: lcode.h,v 1.67 2017/09/28 16:53:29 roberto Exp roberto $
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** $Id: lcode.h,v 1.68 2017/10/04 21:56:32 roberto Exp roberto $
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** Code generator for Lua
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** See Copyright Notice in lua.h
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*/
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@ -88,6 +88,7 @@ LUAI_FUNC void luaK_infix (FuncState *fs, BinOpr op, expdesc *v);
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LUAI_FUNC void luaK_posfix (FuncState *fs, BinOpr op, expdesc *v1,
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expdesc *v2, int line);
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LUAI_FUNC void luaK_setlist (FuncState *fs, int base, int nelems, int tostore);
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LUAI_FUNC void luaK_finish (FuncState *fs);
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#endif
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@ -1,5 +1,5 @@
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/*
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** $Id: lparser.c,v 2.167 2017/10/04 21:53:03 roberto Exp roberto $
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** $Id: lparser.c,v 2.168 2017/11/23 16:35:54 roberto Exp roberto $
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** Lua Parser
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** See Copyright Notice in lua.h
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*/
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@ -547,7 +547,6 @@ static void open_func (LexState *ls, FuncState *fs, BlockCnt *bl) {
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fs->previousline = f->linedefined;
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fs->iwthabs = 0;
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fs->lasttarget = 0;
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fs->jpc = NO_JUMP;
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fs->freereg = 0;
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fs->nk = 0;
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fs->nabslineinfo = 0;
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@ -569,6 +568,7 @@ static void close_func (LexState *ls) {
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Proto *f = fs->f;
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luaK_ret(fs, 0, 0); /* final return */
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leaveblock(fs);
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luaK_finish(fs);
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luaM_reallocvector(L, f->code, f->sizecode, fs->pc, Instruction);
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f->sizecode = fs->pc;
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luaM_reallocvector(L, f->lineinfo, f->sizelineinfo, fs->pc, ls_byte);
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@ -1,5 +1,5 @@
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/*
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** $Id: lparser.h,v 1.77 2017/04/28 20:57:45 roberto Exp roberto $
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** $Id: lparser.h,v 1.78 2017/06/27 11:35:31 roberto Exp roberto $
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** Lua Parser
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** See Copyright Notice in lua.h
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*/
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@ -124,7 +124,6 @@ typedef struct FuncState {
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int pc; /* next position to code (equivalent to 'ncode') */
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int lasttarget; /* 'label' of last 'jump label' */
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int previousline; /* last line that was saved in 'lineinfo' */
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int jpc; /* list of pending jumps to 'pc' */
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int nk; /* number of elements in 'k' */
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int np; /* number of elements in 'p' */
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int nabslineinfo; /* number of elements in 'abslineinfo' */
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10
lvm.c
10
lvm.c
@ -1,5 +1,5 @@
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/*
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** $Id: lvm.c,v 2.321 2017/11/29 13:02:17 roberto Exp roberto $
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** $Id: lvm.c,v 2.322 2017/11/29 16:57:36 roberto Exp roberto $
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** Lua virtual machine
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** See Copyright Notice in lua.h
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*/
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@ -1453,7 +1453,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
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/* next instruction will do the return */
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}
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else { /* tail call */
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if (cl->p->sizep > 0) /* close upvalues from previous call */
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if (TESTARG_k(i)) /* close upvalues from previous call */
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luaF_close(L, ci->func + 1);
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luaD_pretailcall(L, ci, ra, b); /* prepare call frame */
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goto tailcall;
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@ -1462,7 +1462,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
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}
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vmcase(OP_RETURN) {
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int b = GETARG_B(i);
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if (cl->p->sizep > 0)
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if (TESTARG_k(i))
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luaF_close(L, base);
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halfProtect(
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luaD_poscall(L, ci, ra, (b != 0 ? b - 1 : cast_int(L->top - ra)))
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@ -1470,7 +1470,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
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return;
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}
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vmcase(OP_RETURN0) {
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if (cl->p->sizep > 0)
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if (TESTARG_k(i))
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luaF_close(L, base);
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if (L->hookmask)
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halfProtect(luaD_poscall(L, ci, ra, 0)); /* no hurry... */
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@ -1484,7 +1484,7 @@ void luaV_execute (lua_State *L, CallInfo *ci) {
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return;
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}
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vmcase(OP_RETURN1) {
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if (cl->p->sizep > 0)
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if (TESTARG_k(i))
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luaF_close(L, base);
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if (L->hookmask)
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halfProtect(luaD_poscall(L, ci, ra, 1)); /* no hurry... */
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