mirror of
https://github.com/lua/lua.git
synced 2024-11-24 10:43:44 +08:00
comments (*lots* of them) + asserts
This commit is contained in:
Roberto Ierusalimschy
parent
19770b03a9
commit
384d1b47b0
408
lcode.c
408
lcode.c
@ -1,5 +1,5 @@
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/*
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** $Id: lcode.c,v 2.104 2015/12/17 14:52:53 roberto Exp roberto $
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** $Id: lcode.c,v 2.103 2015/11/19 19:16:22 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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@ -36,6 +36,10 @@
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#define hasjumps(e) ((e)->t != (e)->f)
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/*
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** If expression is a numeric constant, fills 'v' with its value
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** and returns 1. Otherwise, returns 0.
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*/
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static int tonumeral(expdesc *e, TValue *v) {
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if (hasjumps(e))
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return 0; /* not a numeral */
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@ -51,13 +55,19 @@ static int tonumeral(expdesc *e, TValue *v) {
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}
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/*
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** Create a OP_LOADNIL instruction, but try to optimize: if the previous
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** instruction is also OP_LOADNIL and ranges are compatible, adjust
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** range of previous instruction instead of emitting a new one. (For
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** instance, 'local a; local b' will generate a single opcode.)
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*/
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void luaK_nil (FuncState *fs, int from, int n) {
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Instruction *previous;
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int l = from + n - 1; /* last register to set nil */
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if (fs->pc > fs->lasttarget) { /* no jumps to current position? */
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previous = &fs->f->code[fs->pc-1];
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if (GET_OPCODE(*previous) == OP_LOADNIL) {
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int pfrom = GETARG_A(*previous);
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if (GET_OPCODE(*previous) == OP_LOADNIL) { /* previous is LOADNIL? */
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int pfrom = GETARG_A(*previous); /* get previous range */
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int pl = pfrom + GETARG_B(*previous);
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if ((pfrom <= from && from <= pl + 1) ||
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(from <= pfrom && pfrom <= l + 1)) { /* can connect both? */
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@ -73,6 +83,10 @@ void luaK_nil (FuncState *fs, int from, int n) {
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}
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/*
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** Gets the destination address of a jump instruction. Used to traverse
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** a list of jumps.
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*/
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static int getjump (FuncState *fs, int pc) {
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int offset = GETARG_sBx(fs->f->code[pc]);
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if (offset == NO_JUMP) /* point to itself represents end of list */
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@ -82,9 +96,13 @@ static int getjump (FuncState *fs, int pc) {
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}
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/*
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** Fix jump instruction at position 'pc' to jump to 'dest'.
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** (Jump addresses are relative in Lua)
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*/
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static void fixjump (FuncState *fs, int pc, int dest) {
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Instruction *jmp = &fs->f->code[pc];
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int offset = dest-(pc+1);
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int offset = dest - (pc + 1);
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lua_assert(dest != NO_JUMP);
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if (abs(offset) > MAXARG_sBx)
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luaX_syntaxerror(fs->ls, "control structure too long");
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@ -92,35 +110,51 @@ static void fixjump (FuncState *fs, int pc, int dest) {
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}
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/*
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** Concatenate jump-list 'l2' into jump-list 'l1'
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*/
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void luaK_concat (FuncState *fs, int *l1, int l2) {
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if (l2 == NO_JUMP) return;
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else if (*l1 == NO_JUMP)
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*l1 = l2;
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if (l2 == NO_JUMP) return; /* nothing to concatenate? */
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else if (*l1 == NO_JUMP) /* no original list? */
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*l1 = l2; /* 'l1' points to 'l2' */
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else {
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int list = *l1;
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int next;
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while ((next = getjump(fs, list)) != NO_JUMP) /* find last element */
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list = next;
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fixjump(fs, list, l2);
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fixjump(fs, list, l2); /* last element links to 'l2' */
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}
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}
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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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*/
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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;
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fs->jpc = NO_JUMP; /* no more jumps to here */
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j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP);
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luaK_concat(fs, &j, jpc); /* keep them on hold */
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return j;
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}
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/*
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** Code a 'return' instruction
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*/
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void luaK_ret (FuncState *fs, int first, int nret) {
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luaK_codeABC(fs, OP_RETURN, first, nret+1, 0);
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}
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/*
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** Code a "conditional jump", that is, a test or comparison opcode
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** followed by a jump. Return jump position.
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*/
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static int condjump (FuncState *fs, OpCode op, int A, int B, int C) {
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luaK_codeABC(fs, op, A, B, C);
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return luaK_jump(fs);
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@ -137,6 +171,11 @@ int luaK_getlabel (FuncState *fs) {
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}
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/*
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** Returns the position of the instruction "controlling" a given
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** jump (that is, its condition), or the jump itself if it is
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** unconditional.
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*/
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static Instruction *getjumpcontrol (FuncState *fs, int pc) {
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Instruction *pi = &fs->f->code[pc];
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if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1))))
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@ -146,25 +185,42 @@ static Instruction *getjumpcontrol (FuncState *fs, int pc) {
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}
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/*
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** Patch destination register for a TESTSET instruction.
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** If instruction in position 'node' is not a TESTSET, return 0 ("fails").
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** Otherwise, if 'reg' is not 'NO_REG', set it as the destination
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** register. Otherwise, change instruction to a simple 'TEST' (produces
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** no register value)
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*/
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static int patchtestreg (FuncState *fs, int node, int reg) {
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Instruction *i = getjumpcontrol(fs, node);
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if (GET_OPCODE(*i) != OP_TESTSET)
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return 0; /* cannot patch other instructions */
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if (reg != NO_REG && reg != GETARG_B(*i))
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SETARG_A(*i, reg);
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else /* no register to put value or register already has the value */
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else {
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/* no register to put value or register already has the value;
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change instruction to simple test */
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*i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i));
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}
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return 1;
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}
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/*
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** Traverse a list of tests ensuring no one produces a value
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*/
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static void removevalues (FuncState *fs, int list) {
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for (; list != NO_JUMP; list = getjump(fs, list))
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patchtestreg(fs, list, NO_REG);
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}
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/*
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** Traverse a list of tests, patching their destination address and
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** registers: tests producing values jump to 'vtarget' (and put their
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** values in 'reg'), other tests jump to 'dtarget'.
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*/
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static void patchlistaux (FuncState *fs, int list, int vtarget, int reg,
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int dtarget) {
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while (list != NO_JUMP) {
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@ -178,21 +234,35 @@ 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);
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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)
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luaK_patchtohere(fs, list);
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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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@ -200,6 +270,11 @@ void luaK_patchlist (FuncState *fs, int list, int target) {
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}
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/*
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** Path all jumps in 'list' to close upvalues up to given 'level'
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** (The assertion checks that jumps either were closing nothing
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** or were closing higher levels, from inner blocks.)
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*/
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void luaK_patchclose (FuncState *fs, int list, int level) {
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level++; /* argument is +1 to reserve 0 as non-op */
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for (; list != NO_JUMP; list = getjump(fs, list)) {
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@ -211,6 +286,10 @@ void luaK_patchclose (FuncState *fs, int list, int level) {
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}
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/*
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** Emit instruction 'i', checking for array sizes and saving also its
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** line information. Return 'i' position.
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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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@ -226,6 +305,10 @@ static int luaK_code (FuncState *fs, Instruction i) {
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}
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/*
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** Format and emit an 'iABC' instruction. (Assertions check consistency
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** of parameters versus opcode.)
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*/
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int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {
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lua_assert(getOpMode(o) == iABC);
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lua_assert(getBMode(o) != OpArgN || b == 0);
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@ -235,6 +318,9 @@ int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) {
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}
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/*
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** Format and emit an 'iABx' instruction.
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*/
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int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
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lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx);
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lua_assert(getCMode(o) == OpArgN);
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@ -243,12 +329,20 @@ int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) {
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}
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/*
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** Emit an "extra argument" instruction (format 'iAx')
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*/
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static int codeextraarg (FuncState *fs, int a) {
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lua_assert(a <= MAXARG_Ax);
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return luaK_code(fs, CREATE_Ax(OP_EXTRAARG, a));
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}
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/*
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** Emit a "load constant" instruction, using either 'OP_LOADK'
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** (if constant index 'k' fits in 18 bits) or an 'OP_LOADKX'
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** instruction with "extra argument".
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*/
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int luaK_codek (FuncState *fs, int reg, int k) {
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if (k <= MAXARG_Bx)
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return luaK_codeABx(fs, OP_LOADK, reg, k);
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@ -260,6 +354,10 @@ int luaK_codek (FuncState *fs, int reg, int k) {
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}
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/*
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** Check register-stack level, keeping track of its maximum size
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** in field 'maxstacksize'
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*/
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void luaK_checkstack (FuncState *fs, int n) {
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int newstack = fs->freereg + n;
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if (newstack > fs->f->maxstacksize) {
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@ -271,12 +369,20 @@ void luaK_checkstack (FuncState *fs, int n) {
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}
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/*
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** Reserve 'n' registers in register stack
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*/
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void luaK_reserveregs (FuncState *fs, int n) {
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luaK_checkstack(fs, n);
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fs->freereg += n;
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}
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/*
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** Free register 'reg', if it is neither a constant index nor
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** a local variable.
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)
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*/
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static void freereg (FuncState *fs, int reg) {
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if (!ISK(reg) && reg >= fs->nactvar) {
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fs->freereg--;
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@ -285,6 +391,9 @@ static void freereg (FuncState *fs, int reg) {
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}
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/*
|
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** Free register used by expression 'e' (if any)
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*/
|
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static void freeexp (FuncState *fs, expdesc *e) {
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if (e->k == VNONRELOC)
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freereg(fs, e->u.info);
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@ -292,8 +401,11 @@ static void freeexp (FuncState *fs, expdesc *e) {
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/*
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** Add constant 'v' to prototype's list of constants (field 'k').
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** Use scanner's table to cache position of constants in constant list
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** and try to reuse constants
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** and try to reuse constants. Because some values should not be used
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** as keys (nil cannot be a key, integer keys can collapse with float
|
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** keys), the caller must provide a useful 'key' for indexing the cache.
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*/
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static int addk (FuncState *fs, TValue *key, TValue *v) {
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lua_State *L = fs->ls->L;
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@ -322,17 +434,21 @@ static int addk (FuncState *fs, TValue *key, TValue *v) {
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}
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/*
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** Add a string to list of constants and return its index.
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*/
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int luaK_stringK (FuncState *fs, TString *s) {
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TValue o;
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setsvalue(fs->ls->L, &o, s);
|
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return addk(fs, &o, &o);
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return addk(fs, &o, &o); /* use string itself as key */
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}
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/*
|
||||
** Integers use userdata as keys to avoid collision with floats with same
|
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** value; conversion to 'void*' used only for hashing, no "precision"
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** problems
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** Add an integer to list of constants and return its index.
|
||||
** Integers use userdata as keys to avoid collision with floats with
|
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** same value; conversion to 'void*' is used only for hashing, so there
|
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** are no "precision" problems.
|
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*/
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int luaK_intK (FuncState *fs, lua_Integer n) {
|
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TValue k, o;
|
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@ -341,21 +457,29 @@ int luaK_intK (FuncState *fs, lua_Integer n) {
|
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return addk(fs, &k, &o);
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}
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|
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/*
|
||||
** Add a float to list of constants and return its index.
|
||||
*/
|
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static int luaK_numberK (FuncState *fs, lua_Number r) {
|
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TValue o;
|
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setfltvalue(&o, r);
|
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return addk(fs, &o, &o);
|
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return addk(fs, &o, &o); /* use number itself as key */
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Add a boolean to list of constants and return its index.
|
||||
*/
|
||||
static int boolK (FuncState *fs, int b) {
|
||||
TValue o;
|
||||
setbvalue(&o, b);
|
||||
return addk(fs, &o, &o);
|
||||
return addk(fs, &o, &o); /* use boolean itself as key */
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Add nil to list of constants and return its index.
|
||||
*/
|
||||
static int nilK (FuncState *fs) {
|
||||
TValue k, v;
|
||||
setnilvalue(&v);
|
||||
@ -365,6 +489,11 @@ static int nilK (FuncState *fs) {
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Fix an expression to return the number of results 'nresults'.
|
||||
** Either 'e' is a multi-ret expression (function call or vararg)
|
||||
** or 'nresults' is LUA_MULTRET (as any expression can satisfy that).
|
||||
*/
|
||||
void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
|
||||
if (e->k == VCALL) { /* expression is an open function call? */
|
||||
SETARG_C(getcode(fs, e), nresults+1);
|
||||
@ -374,12 +503,24 @@ void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) {
|
||||
SETARG_A(getcode(fs, e), fs->freereg);
|
||||
luaK_reserveregs(fs, 1);
|
||||
}
|
||||
else lua_assert(nresults == LUA_MULTRET);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Fix an expression to return one result.
|
||||
** If expression is not a multi-ret expression (function call or
|
||||
** vararg), it already returns one result, so nothing needs to be done.
|
||||
** Function calls become VNONRELOC expressions (as its result comes
|
||||
** fixed in the base register of the call), while vararg expressions
|
||||
** become VRELOCABLE (as OP_VARARG puts its results where it wants).
|
||||
** (Calls are created returning one result, so that does not need
|
||||
** to be fixed.)
|
||||
*/
|
||||
void luaK_setoneret (FuncState *fs, expdesc *e) {
|
||||
if (e->k == VCALL) { /* expression is an open function call? */
|
||||
e->k = VNONRELOC;
|
||||
lua_assert(GETARG_C(getcode(fs, e)) == 2); /* already returns 1 value */
|
||||
e->k = VNONRELOC; /* result has fixed position */
|
||||
e->u.info = GETARG_A(getcode(fs, e));
|
||||
}
|
||||
else if (e->k == VVARARG) {
|
||||
@ -389,10 +530,14 @@ void luaK_setoneret (FuncState *fs, expdesc *e) {
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Ensure that expression 'e' has a value somewhere (either it
|
||||
** is a constant or result is in a register).
|
||||
*/
|
||||
void luaK_dischargevars (FuncState *fs, expdesc *e) {
|
||||
switch (e->k) {
|
||||
case VLOCAL: {
|
||||
e->k = VNONRELOC;
|
||||
e->k = VNONRELOC; /* becomes a non-relocatable value */
|
||||
break;
|
||||
}
|
||||
case VUPVAL: {
|
||||
@ -421,6 +566,10 @@ void luaK_dischargevars (FuncState *fs, expdesc *e) {
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Ensures expression value is in register 'reg' (and therefore
|
||||
** 'e' will become a non-relocatable expression).
|
||||
*/
|
||||
static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
|
||||
luaK_dischargevars(fs, e);
|
||||
switch (e->k) {
|
||||
@ -446,7 +595,7 @@ static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
|
||||
}
|
||||
case VRELOCABLE: {
|
||||
Instruction *pc = &getcode(fs, e);
|
||||
SETARG_A(*pc, reg);
|
||||
SETARG_A(*pc, reg); /* instruction will put result in 'reg' */
|
||||
break;
|
||||
}
|
||||
case VNONRELOC: {
|
||||
@ -455,7 +604,7 @@ static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
|
||||
break;
|
||||
}
|
||||
default: {
|
||||
lua_assert(e->k == VVOID || e->k == VJMP);
|
||||
lua_assert(e->k == VJMP);
|
||||
return; /* nothing to do... */
|
||||
}
|
||||
}
|
||||
@ -464,10 +613,13 @@ static void discharge2reg (FuncState *fs, expdesc *e, int reg) {
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Ensures expression value is in any register.
|
||||
*/
|
||||
static void discharge2anyreg (FuncState *fs, expdesc *e) {
|
||||
if (e->k != VNONRELOC) {
|
||||
luaK_reserveregs(fs, 1);
|
||||
discharge2reg(fs, e, fs->freereg-1);
|
||||
if (e->k != VNONRELOC) { /* no fixed register yet? */
|
||||
luaK_reserveregs(fs, 1); /* get a register */
|
||||
discharge2reg(fs, e, fs->freereg-1); /* put value there */
|
||||
}
|
||||
}
|
||||
|
||||
@ -480,7 +632,7 @@ static int code_loadbool (FuncState *fs, int A, int b, int jump) {
|
||||
|
||||
/*
|
||||
** check whether list has any jump that do not produce a value
|
||||
** (or produce an inverted value)
|
||||
** or produce an inverted value
|
||||
*/
|
||||
static int need_value (FuncState *fs, int list) {
|
||||
for (; list != NO_JUMP; list = getjump(fs, list)) {
|
||||
@ -491,9 +643,16 @@ static int need_value (FuncState *fs, int list) {
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Ensures final expression result (including results from its jump
|
||||
** lists) is in register 'reg'.
|
||||
** If expression has jumps, need to patch these jumps either to
|
||||
** its final position or to "load" instructions (for those tests
|
||||
** that do not produce values).
|
||||
*/
|
||||
static void exp2reg (FuncState *fs, expdesc *e, int reg) {
|
||||
discharge2reg(fs, e, reg);
|
||||
if (e->k == VJMP)
|
||||
if (e->k == VJMP) /* expression itself is a test? */
|
||||
luaK_concat(fs, &e->t, e->u.info); /* put this jump in 't' list */
|
||||
if (hasjumps(e)) {
|
||||
int final; /* position after whole expression */
|
||||
@ -515,6 +674,10 @@ static void exp2reg (FuncState *fs, expdesc *e, int reg) {
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Ensures final expression result (including results from its jump
|
||||
** lists) is in next available register.
|
||||
*/
|
||||
void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
|
||||
luaK_dischargevars(fs, e);
|
||||
freeexp(fs, e);
|
||||
@ -523,26 +686,39 @@ void luaK_exp2nextreg (FuncState *fs, expdesc *e) {
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Ensures final expression result (including results from its jump
|
||||
** lists) is in some (any) register and return that register.
|
||||
*/
|
||||
int luaK_exp2anyreg (FuncState *fs, expdesc *e) {
|
||||
luaK_dischargevars(fs, e);
|
||||
if (e->k == VNONRELOC) {
|
||||
if (!hasjumps(e)) return e->u.info; /* exp is already in a register */
|
||||
if (e->k == VNONRELOC) { /* expression already has a register? */
|
||||
if (!hasjumps(e)) /* no jumps? */
|
||||
return e->u.info; /* result is already in a register */
|
||||
if (e->u.info >= fs->nactvar) { /* reg. is not a local? */
|
||||
exp2reg(fs, e, e->u.info); /* put value on it */
|
||||
exp2reg(fs, e, e->u.info); /* put final result in it */
|
||||
return e->u.info;
|
||||
}
|
||||
}
|
||||
luaK_exp2nextreg(fs, e); /* default */
|
||||
luaK_exp2nextreg(fs, e); /* otherwise, use next available register */
|
||||
return e->u.info;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Ensures final expression result is either in a register or in an
|
||||
** upvalue.
|
||||
*/
|
||||
void luaK_exp2anyregup (FuncState *fs, expdesc *e) {
|
||||
if (e->k != VUPVAL || hasjumps(e))
|
||||
luaK_exp2anyreg(fs, e);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Ensures final expression result is either in a register or it is
|
||||
** a constant.
|
||||
*/
|
||||
void luaK_exp2val (FuncState *fs, expdesc *e) {
|
||||
if (hasjumps(e))
|
||||
luaK_exp2anyreg(fs, e);
|
||||
@ -551,9 +727,14 @@ void luaK_exp2val (FuncState *fs, expdesc *e) {
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Ensures final expression result is in a valid R/K index
|
||||
** (that is, it is either in a register or in 'k' with an index
|
||||
** in the range of R/K indices).
|
||||
*/
|
||||
int luaK_exp2RK (FuncState *fs, expdesc *e) {
|
||||
luaK_exp2val(fs, e);
|
||||
switch (e->k) {
|
||||
switch (e->k) { /* handle constants */
|
||||
case VTRUE:
|
||||
case VFALSE:
|
||||
case VNIL: {
|
||||
@ -587,11 +768,14 @@ int luaK_exp2RK (FuncState *fs, expdesc *e) {
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Generate code to store result of expression 'ex' into variable 'var'.
|
||||
*/
|
||||
void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) {
|
||||
switch (var->k) {
|
||||
case VLOCAL: {
|
||||
freeexp(fs, ex);
|
||||
exp2reg(fs, ex, var->u.info);
|
||||
exp2reg(fs, ex, var->u.info); /* compute 'ex' into proper place */
|
||||
return;
|
||||
}
|
||||
case VUPVAL: {
|
||||
@ -605,29 +789,32 @@ void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) {
|
||||
luaK_codeABC(fs, op, var->u.ind.t, var->u.ind.idx, e);
|
||||
break;
|
||||
}
|
||||
default: {
|
||||
lua_assert(0); /* invalid var kind to store */
|
||||
break;
|
||||
}
|
||||
default: lua_assert(0); /* invalid var kind to store */
|
||||
}
|
||||
freeexp(fs, ex);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Emit SELF instruction (convert expression 'e' into 'e:key(e,').
|
||||
*/
|
||||
void luaK_self (FuncState *fs, expdesc *e, expdesc *key) {
|
||||
int ereg;
|
||||
luaK_exp2anyreg(fs, e);
|
||||
ereg = e->u.info; /* register where 'e' was placed */
|
||||
freeexp(fs, e);
|
||||
e->u.info = fs->freereg; /* base register for op_self */
|
||||
e->k = VNONRELOC;
|
||||
e->k = VNONRELOC; /* self expression has a fixed register */
|
||||
luaK_reserveregs(fs, 2); /* function and 'self' produced by op_self */
|
||||
luaK_codeABC(fs, OP_SELF, e->u.info, ereg, luaK_exp2RK(fs, key));
|
||||
freeexp(fs, key);
|
||||
}
|
||||
|
||||
|
||||
static void invertjump (FuncState *fs, expdesc *e) {
|
||||
/*
|
||||
** Negate condition 'e' (where 'e' is a comparison).
|
||||
*/
|
||||
static void negatecondition (FuncState *fs, expdesc *e) {
|
||||
Instruction *pc = getjumpcontrol(fs, e->u.info);
|
||||
lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET &&
|
||||
GET_OPCODE(*pc) != OP_TEST);
|
||||
@ -635,6 +822,12 @@ static void invertjump (FuncState *fs, expdesc *e) {
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Emit instruction to jump if 'e' is 'cond' (that is, if 'cond'
|
||||
** is true, code will jump if 'e' is true.) Return jump position.
|
||||
** Optimize when 'e' is 'not' something, inverting the condition
|
||||
** and removing the 'not'.
|
||||
*/
|
||||
static int jumponcond (FuncState *fs, expdesc *e, int cond) {
|
||||
if (e->k == VRELOCABLE) {
|
||||
Instruction ie = getcode(fs, e);
|
||||
@ -650,13 +843,16 @@ static int jumponcond (FuncState *fs, expdesc *e, int cond) {
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Emit code to go through if 'e' is true, jump otherwise.
|
||||
*/
|
||||
void luaK_goiftrue (FuncState *fs, expdesc *e) {
|
||||
int pc; /* pc of last jump */
|
||||
int pc; /* pc of new jump */
|
||||
luaK_dischargevars(fs, e);
|
||||
switch (e->k) {
|
||||
case VJMP: {
|
||||
invertjump(fs, e);
|
||||
pc = e->u.info;
|
||||
case VJMP: { /* condition? */
|
||||
negatecondition(fs, e); /* jump when it is false */
|
||||
pc = e->u.info; /* save jump position */
|
||||
break;
|
||||
}
|
||||
case VK: case VKFLT: case VKINT: case VTRUE: {
|
||||
@ -664,22 +860,25 @@ void luaK_goiftrue (FuncState *fs, expdesc *e) {
|
||||
break;
|
||||
}
|
||||
default: {
|
||||
pc = jumponcond(fs, e, 0);
|
||||
pc = jumponcond(fs, e, 0); /* jump when false */
|
||||
break;
|
||||
}
|
||||
}
|
||||
luaK_concat(fs, &e->f, pc); /* insert last jump in 'f' list */
|
||||
luaK_patchtohere(fs, e->t);
|
||||
luaK_concat(fs, &e->f, pc); /* insert new jump in false list */
|
||||
luaK_patchtohere(fs, e->t); /* true list jumps to here (to go through) */
|
||||
e->t = NO_JUMP;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Emit code to go through if 'e' is false, jump otherwise.
|
||||
*/
|
||||
void luaK_goiffalse (FuncState *fs, expdesc *e) {
|
||||
int pc; /* pc of last jump */
|
||||
int pc; /* pc of new jump */
|
||||
luaK_dischargevars(fs, e);
|
||||
switch (e->k) {
|
||||
case VJMP: {
|
||||
pc = e->u.info;
|
||||
pc = e->u.info; /* already jump if true */
|
||||
break;
|
||||
}
|
||||
case VNIL: case VFALSE: {
|
||||
@ -687,29 +886,32 @@ void luaK_goiffalse (FuncState *fs, expdesc *e) {
|
||||
break;
|
||||
}
|
||||
default: {
|
||||
pc = jumponcond(fs, e, 1);
|
||||
pc = jumponcond(fs, e, 1); /* jump if true */
|
||||
break;
|
||||
}
|
||||
}
|
||||
luaK_concat(fs, &e->t, pc); /* insert last jump in 't' list */
|
||||
luaK_patchtohere(fs, e->f);
|
||||
luaK_concat(fs, &e->t, pc); /* insert new jump in 't' list */
|
||||
luaK_patchtohere(fs, e->f); /* false list jumps to here (to go through) */
|
||||
e->f = NO_JUMP;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Code 'not e', doing constant folding.
|
||||
*/
|
||||
static void codenot (FuncState *fs, expdesc *e) {
|
||||
luaK_dischargevars(fs, e);
|
||||
switch (e->k) {
|
||||
case VNIL: case VFALSE: {
|
||||
e->k = VTRUE;
|
||||
e->k = VTRUE; /* true == not nil == not false */
|
||||
break;
|
||||
}
|
||||
case VK: case VKFLT: case VKINT: case VTRUE: {
|
||||
e->k = VFALSE;
|
||||
e->k = VFALSE; /* false == not "x" == not 0.5 == not 1 == not true */
|
||||
break;
|
||||
}
|
||||
case VJMP: {
|
||||
invertjump(fs, e);
|
||||
negatecondition(fs, e);
|
||||
break;
|
||||
}
|
||||
case VRELOCABLE:
|
||||
@ -720,30 +922,32 @@ static void codenot (FuncState *fs, expdesc *e) {
|
||||
e->k = VRELOCABLE;
|
||||
break;
|
||||
}
|
||||
default: {
|
||||
lua_assert(0); /* cannot happen */
|
||||
break;
|
||||
}
|
||||
default: lua_assert(0); /* cannot happen */
|
||||
}
|
||||
/* interchange true and false lists */
|
||||
{ int temp = e->f; e->f = e->t; e->t = temp; }
|
||||
removevalues(fs, e->f);
|
||||
removevalues(fs, e->f); /* values are useless when negated */
|
||||
removevalues(fs, e->t);
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Create expression 't[k]'. 't' must have its final result already in a
|
||||
** register or upvalue.
|
||||
*/
|
||||
void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) {
|
||||
lua_assert(!hasjumps(t));
|
||||
t->u.ind.t = t->u.info;
|
||||
t->u.ind.idx = luaK_exp2RK(fs, k);
|
||||
t->u.ind.vt = (t->k == VUPVAL) ? VUPVAL
|
||||
: check_exp(vkisinreg(t->k), VLOCAL);
|
||||
lua_assert(!hasjumps(t) && (vkisinreg(t->k) || t->k == VUPVAL));
|
||||
t->u.ind.t = t->u.info; /* register or upvalue index */
|
||||
t->u.ind.idx = luaK_exp2RK(fs, k); /* R/K index for key */
|
||||
t->u.ind.vt = (t->k == VUPVAL) ? VUPVAL : VLOCAL;
|
||||
t->k = VINDEXED;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** return false if folding can raise an error
|
||||
** Return false if folding can raise an error.
|
||||
** Bitwise operations need operands convertible to integers; division
|
||||
** operations cannot have 0 as divisor.
|
||||
*/
|
||||
static int validop (int op, TValue *v1, TValue *v2) {
|
||||
switch (op) {
|
||||
@ -760,7 +964,8 @@ static int validop (int op, TValue *v1, TValue *v2) {
|
||||
|
||||
|
||||
/*
|
||||
** Try to "constant-fold" an operation; return 1 iff successful
|
||||
** Try to "constant-fold" an operation; return 1 iff successful.
|
||||
** (In this case, 'e1' has the final result.)
|
||||
*/
|
||||
static int constfolding (FuncState *fs, int op, expdesc *e1, expdesc *e2) {
|
||||
TValue v1, v2, res;
|
||||
@ -771,7 +976,7 @@ static int constfolding (FuncState *fs, int op, expdesc *e1, expdesc *e2) {
|
||||
e1->k = VKINT;
|
||||
e1->u.ival = ivalue(&res);
|
||||
}
|
||||
else { /* folds neither NaN nor 0.0 (to avoid collapsing with -0.0) */
|
||||
else { /* folds neither NaN nor 0.0 (to avoid problems with -0.0) */
|
||||
lua_Number n = fltvalue(&res);
|
||||
if (luai_numisnan(n) || n == 0)
|
||||
return 0;
|
||||
@ -783,15 +988,19 @@ static int constfolding (FuncState *fs, int op, expdesc *e1, expdesc *e2) {
|
||||
|
||||
|
||||
/*
|
||||
** Code for binary and unary expressions that "produce values"
|
||||
** (arithmetic operations, bitwise operations, concat, length). First
|
||||
** try to do constant folding (only for numeric [arithmetic and
|
||||
** bitwise] operations, which is what 'lua_arith' accepts).
|
||||
** Expression to produce final result will be encoded in 'e1'.
|
||||
** Emit code for binary and unary expressions that "produce values"
|
||||
** (everything but logical operators 'and', 'or' and comparison
|
||||
** operators).
|
||||
** First try to do constant folding (only for numeric [arithmetic and
|
||||
** bitwise] operations, which is what 'lua_arith' accepts). Expression
|
||||
** to produce final result will be encoded in 'e1'.
|
||||
** (The "free registers in proper order" reason is tricky: because
|
||||
** expression evaluation can be delayed, the final numbering for
|
||||
** registers in 'e1' and 'e2' depends on how each one was delayed.)
|
||||
*/
|
||||
static void codeexpval (FuncState *fs, OpCode op,
|
||||
expdesc *e1, expdesc *e2, int line) {
|
||||
lua_assert(op >= OP_ADD);
|
||||
lua_assert(OP_ADD <= op && op <= OP_CONCAT);
|
||||
if (op <= OP_BNOT && constfolding(fs, (op - OP_ADD) + LUA_OPADD, e1, e2))
|
||||
return; /* result has been folded */
|
||||
else {
|
||||
@ -820,10 +1029,16 @@ static void codeexpval (FuncState *fs, OpCode op,
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Emit code for comparisons.
|
||||
** Code will jump if result equals 'cond' ('cond' true <=> code will
|
||||
** jump if result is true).
|
||||
*/
|
||||
static void codecomp (FuncState *fs, OpCode op, int cond, expdesc *e1,
|
||||
expdesc *e2) {
|
||||
int o1 = luaK_exp2RK(fs, e1);
|
||||
int o2 = luaK_exp2RK(fs, e2);
|
||||
lua_assert(OP_EQ <= op && op <= OP_LE); /* comparison operation */
|
||||
freeexp(fs, e2);
|
||||
freeexp(fs, e1);
|
||||
if (cond == 0 && op != OP_EQ) {
|
||||
@ -836,8 +1051,11 @@ static void codecomp (FuncState *fs, OpCode op, int cond, expdesc *e1,
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Aplly prefix operation 'op' to expression 'e'.
|
||||
*/
|
||||
void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e, int line) {
|
||||
expdesc e2;
|
||||
expdesc e2; /* fake 2nd operand */
|
||||
e2.t = e2.f = NO_JUMP; e2.k = VKINT; e2.u.ival = 0;
|
||||
switch (op) {
|
||||
case OPR_MINUS: case OPR_BNOT: case OPR_LEN: {
|
||||
@ -850,14 +1068,18 @@ void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e, int line) {
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Process 1st operand 'v' of binary operation 'op' before reading
|
||||
** 2nd operand.
|
||||
*/
|
||||
void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
|
||||
switch (op) {
|
||||
case OPR_AND: {
|
||||
luaK_goiftrue(fs, v);
|
||||
luaK_goiftrue(fs, v); /* go ahead only if 'v' is true */
|
||||
break;
|
||||
}
|
||||
case OPR_OR: {
|
||||
luaK_goiffalse(fs, v);
|
||||
luaK_goiffalse(fs, v); /* go ahead only if 'v' is false */
|
||||
break;
|
||||
}
|
||||
case OPR_CONCAT: {
|
||||
@ -869,7 +1091,9 @@ void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
|
||||
case OPR_MOD: case OPR_POW:
|
||||
case OPR_BAND: case OPR_BOR: case OPR_BXOR:
|
||||
case OPR_SHL: case OPR_SHR: {
|
||||
if (!tonumeral(v, NULL)) luaK_exp2RK(fs, v);
|
||||
if (!tonumeral(v, NULL))
|
||||
luaK_exp2RK(fs, v);
|
||||
/* else keep numeral, which may be folded with 2nd operand */
|
||||
break;
|
||||
}
|
||||
default: {
|
||||
@ -880,18 +1104,24 @@ void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) {
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Finalize code for binary operation, after reading 2nd operand.
|
||||
** For '(a .. b .. c)' (which is '(a .. (b .. c))', because
|
||||
** concatenation is right associative), merge second CONCAT into first
|
||||
** one.
|
||||
*/
|
||||
void luaK_posfix (FuncState *fs, BinOpr op,
|
||||
expdesc *e1, expdesc *e2, int line) {
|
||||
switch (op) {
|
||||
case OPR_AND: {
|
||||
lua_assert(e1->t == NO_JUMP); /* list must be closed */
|
||||
lua_assert(e1->t == NO_JUMP); /* list closed by 'luK_infix' */
|
||||
luaK_dischargevars(fs, e2);
|
||||
luaK_concat(fs, &e2->f, e1->f);
|
||||
*e1 = *e2;
|
||||
break;
|
||||
}
|
||||
case OPR_OR: {
|
||||
lua_assert(e1->f == NO_JUMP); /* list must be closed */
|
||||
lua_assert(e1->f == NO_JUMP); /* list closed by 'luK_infix' */
|
||||
luaK_dischargevars(fs, e2);
|
||||
luaK_concat(fs, &e2->t, e1->t);
|
||||
*e1 = *e2;
|
||||
@ -931,15 +1161,25 @@ void luaK_posfix (FuncState *fs, BinOpr op,
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Change line information associated with current position.
|
||||
*/
|
||||
void luaK_fixline (FuncState *fs, int line) {
|
||||
fs->f->lineinfo[fs->pc - 1] = line;
|
||||
}
|
||||
|
||||
|
||||
/*
|
||||
** Emit a SETLIST instruction.
|
||||
** 'base' is register that keeps table;
|
||||
** 'nelems' is #table plus those to be stored now;
|
||||
** 'tostore' is number of values (in registers 'base + 1',...) to add to
|
||||
** table (or LUA_MULTRET to add up to stack top).
|
||||
*/
|
||||
void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) {
|
||||
int c = (nelems - 1)/LFIELDS_PER_FLUSH + 1;
|
||||
int b = (tostore == LUA_MULTRET) ? 0 : tostore;
|
||||
lua_assert(tostore != 0);
|
||||
lua_assert(tostore != 0 && tostore <= LFIELDS_PER_FLUSH);
|
||||
if (c <= MAXARG_C)
|
||||
luaK_codeABC(fs, OP_SETLIST, base, b, c);
|
||||
else if (c <= MAXARG_Ax) {
|
||||
|
||||
Loading…
Reference in New Issue
Block a user