tools/wrk/deps/luajit/dynasm/dasm_x86.h
/*
** DynASM x86 encoding engine.
** Copyright (C) 2005-2013 Mike Pall. All rights reserved.
** Released under the MIT license. See dynasm.lua for full copyright notice.
*/
#include <stddef.h>
#include <stdarg.h>
#include <string.h>
#include <stdlib.h>
#define DASM_ARCH "x86"
#ifndef DASM_EXTERN
#define DASM_EXTERN(a,b,c,d) 0
#endif
/* Action definitions. DASM_STOP must be 255. */
enum {
DASM_DISP = 233,
DASM_IMM_S, DASM_IMM_B, DASM_IMM_W, DASM_IMM_D, DASM_IMM_WB, DASM_IMM_DB,
DASM_VREG, DASM_SPACE, DASM_SETLABEL, DASM_REL_A, DASM_REL_LG, DASM_REL_PC,
DASM_IMM_LG, DASM_IMM_PC, DASM_LABEL_LG, DASM_LABEL_PC, DASM_ALIGN,
DASM_EXTERN, DASM_ESC, DASM_MARK, DASM_SECTION, DASM_STOP
};
/* Maximum number of section buffer positions for a single dasm_put() call. */
#define DASM_MAXSECPOS 25
/* DynASM encoder status codes. Action list offset or number are or'ed in. */
#define DASM_S_OK 0x00000000
#define DASM_S_NOMEM 0x01000000
#define DASM_S_PHASE 0x02000000
#define DASM_S_MATCH_SEC 0x03000000
#define DASM_S_RANGE_I 0x11000000
#define DASM_S_RANGE_SEC 0x12000000
#define DASM_S_RANGE_LG 0x13000000
#define DASM_S_RANGE_PC 0x14000000
#define DASM_S_RANGE_VREG 0x15000000
#define DASM_S_UNDEF_L 0x21000000
#define DASM_S_UNDEF_PC 0x22000000
/* Macros to convert positions (8 bit section + 24 bit index). */
#define DASM_POS2IDX(pos) ((pos)&0x00ffffff)
#define DASM_POS2BIAS(pos) ((pos)&0xff000000)
#define DASM_SEC2POS(sec) ((sec)<<24)
#define DASM_POS2SEC(pos) ((pos)>>24)
#define DASM_POS2PTR(D, pos) (D->sections[DASM_POS2SEC(pos)].rbuf + (pos))
/* Action list type. */
typedef const unsigned char *dasm_ActList;
/* Per-section structure. */
typedef struct dasm_Section {
int *rbuf; /* Biased buffer pointer (negative section bias). */
int *buf; /* True buffer pointer. */
size_t bsize; /* Buffer size in bytes. */
int pos; /* Biased buffer position. */
int epos; /* End of biased buffer position - max single put. */
int ofs; /* Byte offset into section. */
} dasm_Section;
/* Core structure holding the DynASM encoding state. */
struct dasm_State {
size_t psize; /* Allocated size of this structure. */
dasm_ActList actionlist; /* Current actionlist pointer. */
int *lglabels; /* Local/global chain/pos ptrs. */
size_t lgsize;
int *pclabels; /* PC label chains/pos ptrs. */
size_t pcsize;
void **globals; /* Array of globals (bias -10). */
dasm_Section *section; /* Pointer to active section. */
size_t codesize; /* Total size of all code sections. */
int maxsection; /* 0 <= sectionidx < maxsection. */
int status; /* Status code. */
dasm_Section sections[1]; /* All sections. Alloc-extended. */
};
/* The size of the core structure depends on the max. number of sections. */
#define DASM_PSZ(ms) (sizeof(dasm_State)+(ms-1)*sizeof(dasm_Section))
/* Initialize DynASM state. */
void dasm_init(Dst_DECL, int maxsection)
{
dasm_State *D;
size_t psz = 0;
int i;
Dst_REF = NULL;
DASM_M_GROW(Dst, struct dasm_State, Dst_REF, psz, DASM_PSZ(maxsection));
D = Dst_REF;
D->psize = psz;
D->lglabels = NULL;
D->lgsize = 0;
D->pclabels = NULL;
D->pcsize = 0;
D->globals = NULL;
D->maxsection = maxsection;
for (i = 0; i < maxsection; i++) {
D->sections[i].buf = NULL; /* Need this for pass3. */
D->sections[i].rbuf = D->sections[i].buf - DASM_SEC2POS(i);
D->sections[i].bsize = 0;
D->sections[i].epos = 0; /* Wrong, but is recalculated after resize. */
}
}
/* Free DynASM state. */
void dasm_free(Dst_DECL)
{
dasm_State *D = Dst_REF;
int i;
for (i = 0; i < D->maxsection; i++)
if (D->sections[i].buf)
DASM_M_FREE(Dst, D->sections[i].buf, D->sections[i].bsize);
if (D->pclabels) DASM_M_FREE(Dst, D->pclabels, D->pcsize);
if (D->lglabels) DASM_M_FREE(Dst, D->lglabels, D->lgsize);
DASM_M_FREE(Dst, D, D->psize);
}
/* Setup global label array. Must be called before dasm_setup(). */
void dasm_setupglobal(Dst_DECL, void **gl, unsigned int maxgl)
{
dasm_State *D = Dst_REF;
D->globals = gl - 10; /* Negative bias to compensate for locals. */
DASM_M_GROW(Dst, int, D->lglabels, D->lgsize, (10+maxgl)*sizeof(int));
}
/* Grow PC label array. Can be called after dasm_setup(), too. */
void dasm_growpc(Dst_DECL, unsigned int maxpc)
{
dasm_State *D = Dst_REF;
size_t osz = D->pcsize;
DASM_M_GROW(Dst, int, D->pclabels, D->pcsize, maxpc*sizeof(int));
memset((void *)(((unsigned char *)D->pclabels)+osz), 0, D->pcsize-osz);
}
/* Setup encoder. */
void dasm_setup(Dst_DECL, const void *actionlist)
{
dasm_State *D = Dst_REF;
int i;
D->actionlist = (dasm_ActList)actionlist;
D->status = DASM_S_OK;
D->section = &D->sections[0];
memset((void *)D->lglabels, 0, D->lgsize);
if (D->pclabels) memset((void *)D->pclabels, 0, D->pcsize);
for (i = 0; i < D->maxsection; i++) {
D->sections[i].pos = DASM_SEC2POS(i);
D->sections[i].ofs = 0;
}
}
#ifdef DASM_CHECKS
#define CK(x, st) \
do { if (!(x)) { \
D->status = DASM_S_##st|(int)(p-D->actionlist-1); return; } } while (0)
#define CKPL(kind, st) \
do { if ((size_t)((char *)pl-(char *)D->kind##labels) >= D->kind##size) { \
D->status=DASM_S_RANGE_##st|(int)(p-D->actionlist-1); return; } } while (0)
#else
#define CK(x, st) ((void)0)
#define CKPL(kind, st) ((void)0)
#endif
/* Pass 1: Store actions and args, link branches/labels, estimate offsets. */
void dasm_put(Dst_DECL, int start, ...)
{
va_list ap;
dasm_State *D = Dst_REF;
dasm_ActList p = D->actionlist + start;
dasm_Section *sec = D->section;
int pos = sec->pos, ofs = sec->ofs, mrm = 4;
int *b;
if (pos >= sec->epos) {
DASM_M_GROW(Dst, int, sec->buf, sec->bsize,
sec->bsize + 2*DASM_MAXSECPOS*sizeof(int));
sec->rbuf = sec->buf - DASM_POS2BIAS(pos);
sec->epos = (int)sec->bsize/sizeof(int) - DASM_MAXSECPOS+DASM_POS2BIAS(pos);
}
b = sec->rbuf;
b[pos++] = start;
va_start(ap, start);
while (1) {
int action = *p++;
if (action < DASM_DISP) {
ofs++;
} else if (action <= DASM_REL_A) {
int n = va_arg(ap, int);
b[pos++] = n;
switch (action) {
case DASM_DISP:
if (n == 0) { if ((mrm&7) == 4) mrm = p[-2]; if ((mrm&7) != 5) break; }
case DASM_IMM_DB: if (((n+128)&-256) == 0) goto ob;
case DASM_REL_A: /* Assumes ptrdiff_t is int. !x64 */
case DASM_IMM_D: ofs += 4; break;
case DASM_IMM_S: CK(((n+128)&-256) == 0, RANGE_I); goto ob;
case DASM_IMM_B: CK((n&-256) == 0, RANGE_I); ob: ofs++; break;
case DASM_IMM_WB: if (((n+128)&-256) == 0) goto ob;
case DASM_IMM_W: CK((n&-65536) == 0, RANGE_I); ofs += 2; break;
case DASM_SPACE: p++; ofs += n; break;
case DASM_SETLABEL: b[pos-2] = -0x40000000; break; /* Neg. label ofs. */
case DASM_VREG: CK((n&-8) == 0 && (n != 4 || (*p&1) == 0), RANGE_VREG);
if (*p++ == 1 && *p == DASM_DISP) mrm = n; continue;
}
mrm = 4;
} else {
int *pl, n;
switch (action) {
case DASM_REL_LG:
case DASM_IMM_LG:
n = *p++; pl = D->lglabels + n;
/* Bkwd rel or global. */
if (n <= 246) { CK(n>=10||*pl<0, RANGE_LG); CKPL(lg, LG); goto putrel; }
pl -= 246; n = *pl;
if (n < 0) n = 0; /* Start new chain for fwd rel if label exists. */
goto linkrel;
case DASM_REL_PC:
case DASM_IMM_PC: pl = D->pclabels + va_arg(ap, int); CKPL(pc, PC);
putrel:
n = *pl;
if (n < 0) { /* Label exists. Get label pos and store it. */
b[pos] = -n;
} else {
linkrel:
b[pos] = n; /* Else link to rel chain, anchored at label. */
*pl = pos;
}
pos++;
ofs += 4; /* Maximum offset needed. */
if (action == DASM_REL_LG || action == DASM_REL_PC)
b[pos++] = ofs; /* Store pass1 offset estimate. */
break;
case DASM_LABEL_LG: pl = D->lglabels + *p++; CKPL(lg, LG); goto putlabel;
case DASM_LABEL_PC: pl = D->pclabels + va_arg(ap, int); CKPL(pc, PC);
putlabel:
n = *pl; /* n > 0: Collapse rel chain and replace with label pos. */
while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = pos; }
*pl = -pos; /* Label exists now. */
b[pos++] = ofs; /* Store pass1 offset estimate. */
break;
case DASM_ALIGN:
ofs += *p++; /* Maximum alignment needed (arg is 2**n-1). */
b[pos++] = ofs; /* Store pass1 offset estimate. */
break;
case DASM_EXTERN: p += 2; ofs += 4; break;
case DASM_ESC: p++; ofs++; break;
case DASM_MARK: mrm = p[-2]; break;
case DASM_SECTION:
n = *p; CK(n < D->maxsection, RANGE_SEC); D->section = &D->sections[n];
case DASM_STOP: goto stop;
}
}
}
stop:
va_end(ap);
sec->pos = pos;
sec->ofs = ofs;
}
#undef CK
/* Pass 2: Link sections, shrink branches/aligns, fix label offsets. */
int dasm_link(Dst_DECL, size_t *szp)
{
dasm_State *D = Dst_REF;
int secnum;
int ofs = 0;
#ifdef DASM_CHECKS
*szp = 0;
if (D->status != DASM_S_OK) return D->status;
{
int pc;
for (pc = 0; pc*sizeof(int) < D->pcsize; pc++)
if (D->pclabels[pc] > 0) return DASM_S_UNDEF_PC|pc;
}
#endif
{ /* Handle globals not defined in this translation unit. */
int idx;
for (idx = 10; idx*sizeof(int) < D->lgsize; idx++) {
int n = D->lglabels[idx];
/* Undefined label: Collapse rel chain and replace with marker (< 0). */
while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = -idx; }
}
}
/* Combine all code sections. No support for data sections (yet). */
for (secnum = 0; secnum < D->maxsection; secnum++) {
dasm_Section *sec = D->sections + secnum;
int *b = sec->rbuf;
int pos = DASM_SEC2POS(secnum);
int lastpos = sec->pos;
while (pos != lastpos) {
dasm_ActList p = D->actionlist + b[pos++];
while (1) {
int op, action = *p++;
switch (action) {
case DASM_REL_LG: p++; op = p[-3]; goto rel_pc;
case DASM_REL_PC: op = p[-2]; rel_pc: {
int shrink = op == 0xe9 ? 3 : ((op&0xf0) == 0x80 ? 4 : 0);
if (shrink) { /* Shrinkable branch opcode? */
int lofs, lpos = b[pos];
if (lpos < 0) goto noshrink; /* Ext global? */
lofs = *DASM_POS2PTR(D, lpos);
if (lpos > pos) { /* Fwd label: add cumulative section offsets. */
int i;
for (i = secnum; i < DASM_POS2SEC(lpos); i++)
lofs += D->sections[i].ofs;
} else {
lofs -= ofs; /* Bkwd label: unfix offset. */
}
lofs -= b[pos+1]; /* Short branch ok? */
if (lofs >= -128-shrink && lofs <= 127) ofs -= shrink; /* Yes. */
else { noshrink: shrink = 0; } /* No, cannot shrink op. */
}
b[pos+1] = shrink;
pos += 2;
break;
}
case DASM_SPACE: case DASM_IMM_LG: case DASM_VREG: p++;
case DASM_DISP: case DASM_IMM_S: case DASM_IMM_B: case DASM_IMM_W:
case DASM_IMM_D: case DASM_IMM_WB: case DASM_IMM_DB:
case DASM_SETLABEL: case DASM_REL_A: case DASM_IMM_PC: pos++; break;
case DASM_LABEL_LG: p++;
case DASM_LABEL_PC: b[pos++] += ofs; break; /* Fix label offset. */
case DASM_ALIGN: ofs -= (b[pos++]+ofs)&*p++; break; /* Adjust ofs. */
case DASM_EXTERN: p += 2; break;
case DASM_ESC: p++; break;
case DASM_MARK: break;
case DASM_SECTION: case DASM_STOP: goto stop;
}
}
stop: (void)0;
}
ofs += sec->ofs; /* Next section starts right after current section. */
}
D->codesize = ofs; /* Total size of all code sections */
*szp = ofs;
return DASM_S_OK;
}
#define dasmb(x) *cp++ = (unsigned char)(x)
#ifndef DASM_ALIGNED_WRITES
#define dasmw(x) \
do { *((unsigned short *)cp) = (unsigned short)(x); cp+=2; } while (0)
#define dasmd(x) \
do { *((unsigned int *)cp) = (unsigned int)(x); cp+=4; } while (0)
#else
#define dasmw(x) do { dasmb(x); dasmb((x)>>8); } while (0)
#define dasmd(x) do { dasmw(x); dasmw((x)>>16); } while (0)
#endif
/* Pass 3: Encode sections. */
int dasm_encode(Dst_DECL, void *buffer)
{
dasm_State *D = Dst_REF;
unsigned char *base = (unsigned char *)buffer;
unsigned char *cp = base;
int secnum;
/* Encode all code sections. No support for data sections (yet). */
for (secnum = 0; secnum < D->maxsection; secnum++) {
dasm_Section *sec = D->sections + secnum;
int *b = sec->buf;
int *endb = sec->rbuf + sec->pos;
while (b != endb) {
dasm_ActList p = D->actionlist + *b++;
unsigned char *mark = NULL;
while (1) {
int action = *p++;
int n = (action >= DASM_DISP && action <= DASM_ALIGN) ? *b++ : 0;
switch (action) {
case DASM_DISP: if (!mark) mark = cp; {
unsigned char *mm = mark;
if (*p != DASM_IMM_DB && *p != DASM_IMM_WB) mark = NULL;
if (n == 0) { int mrm = mm[-1]&7; if (mrm == 4) mrm = mm[0]&7;
if (mrm != 5) { mm[-1] -= 0x80; break; } }
if (((n+128) & -256) != 0) goto wd; else mm[-1] -= 0x40;
}
case DASM_IMM_S: case DASM_IMM_B: wb: dasmb(n); break;
case DASM_IMM_DB: if (((n+128)&-256) == 0) {
db: if (!mark) mark = cp; mark[-2] += 2; mark = NULL; goto wb;
} else mark = NULL;
case DASM_IMM_D: wd: dasmd(n); break;
case DASM_IMM_WB: if (((n+128)&-256) == 0) goto db; else mark = NULL;
case DASM_IMM_W: dasmw(n); break;
case DASM_VREG: { int t = *p++; if (t >= 2) n<<=3; cp[-1] |= n; break; }
case DASM_REL_LG: p++; if (n >= 0) goto rel_pc;
b++; n = (int)(ptrdiff_t)D->globals[-n];
case DASM_REL_A: rel_a: n -= (int)(ptrdiff_t)(cp+4); goto wd; /* !x64 */
case DASM_REL_PC: rel_pc: {
int shrink = *b++;
int *pb = DASM_POS2PTR(D, n); if (*pb < 0) { n = pb[1]; goto rel_a; }
n = *pb - ((int)(cp-base) + 4-shrink);
if (shrink == 0) goto wd;
if (shrink == 4) { cp--; cp[-1] = *cp-0x10; } else cp[-1] = 0xeb;
goto wb;
}
case DASM_IMM_LG:
p++; if (n < 0) { n = (int)(ptrdiff_t)D->globals[-n]; goto wd; }
case DASM_IMM_PC: {
int *pb = DASM_POS2PTR(D, n);
n = *pb < 0 ? pb[1] : (*pb + (int)(ptrdiff_t)base);
goto wd;
}
case DASM_LABEL_LG: {
int idx = *p++;
if (idx >= 10)
D->globals[idx] = (void *)(base + (*p == DASM_SETLABEL ? *b : n));
break;
}
case DASM_LABEL_PC: case DASM_SETLABEL: break;
case DASM_SPACE: { int fill = *p++; while (n--) *cp++ = fill; break; }
case DASM_ALIGN:
n = *p++;
while (((cp-base) & n)) *cp++ = 0x90; /* nop */
break;
case DASM_EXTERN: n = DASM_EXTERN(Dst, cp, p[1], *p); p += 2; goto wd;
case DASM_MARK: mark = cp; break;
case DASM_ESC: action = *p++;
default: *cp++ = action; break;
case DASM_SECTION: case DASM_STOP: goto stop;
}
}
stop: (void)0;
}
}
if (base + D->codesize != cp) /* Check for phase errors. */
return DASM_S_PHASE;
return DASM_S_OK;
}
/* Get PC label offset. */
int dasm_getpclabel(Dst_DECL, unsigned int pc)
{
dasm_State *D = Dst_REF;
if (pc*sizeof(int) < D->pcsize) {
int pos = D->pclabels[pc];
if (pos < 0) return *DASM_POS2PTR(D, -pos);
if (pos > 0) return -1; /* Undefined. */
}
return -2; /* Unused or out of range. */
}
#ifdef DASM_CHECKS
/* Optional sanity checker to call between isolated encoding steps. */
int dasm_checkstep(Dst_DECL, int secmatch)
{
dasm_State *D = Dst_REF;
if (D->status == DASM_S_OK) {
int i;
for (i = 1; i <= 9; i++) {
if (D->lglabels[i] > 0) { D->status = DASM_S_UNDEF_L|i; break; }
D->lglabels[i] = 0;
}
}
if (D->status == DASM_S_OK && secmatch >= 0 &&
D->section != &D->sections[secmatch])
D->status = DASM_S_MATCH_SEC|(int)(D->section-D->sections);
return D->status;
}
#endif