Edit File: dasm_x86.h
/* ** DynASM x86 encoding engine. ** Copyright (C) 2005-2021 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)) /* Perform potentially overflowing pointer operations in a way that avoids UB. */ #define DASM_PTR_SUB(p1, off) ((void *) ((uintptr_t) (p1) - sizeof(*p1) * (uintptr_t) (off))) #define DASM_PTR_ADD(p1, off) ((void *) ((uintptr_t) (p1) + sizeof(*p1) * (uintptr_t) (off))) /* 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 = DASM_PTR_SUB(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 = -1; 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 < 0) mrm = p[-2]; if ((mrm&7) != 5) break; } /* fallthrough */ case DASM_IMM_DB: if ((((unsigned)n+128)&-256) == 0) goto ob; /* fallthrough */ 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; /* fallthrough */ 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&-16) == 0 && (n != 4 || (*p>>5) != 2), RANGE_VREG); if (*p < 0x40 && p[1] == DASM_DISP) mrm = n; if (*p < 0x20 && (n&7) == 4) ofs++; switch ((*p++ >> 3) & 3) { case 3: n |= b[pos-3]; /* fallthrough */ case 2: n |= b[pos-2]; /* fallthrough */ case 1: if (n <= 7) { b[pos-1] |= 0x10; ofs--; } } continue; } mrm = -1; } 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. */ } else if (sizeof(ptrdiff_t) == 8) { ofs += 4; } 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++]; int op = 0; while (1) { int action = *p++; switch (action) { case DASM_REL_LG: p++; /* fallthrough */ case DASM_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; } /* fallthrough */ 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++; /* fallthrough */ 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: op = *p++; break; case DASM_MARK: break; case DASM_SECTION: case DASM_STOP: goto stop; default: op = action; break; } } 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 typedef ZEND_SET_ALIGNED(1, unsigned short unaligned_short); typedef ZEND_SET_ALIGNED(1, unsigned int unaligned_int); typedef ZEND_SET_ALIGNED(1, unsigned long long unaligned_long_long); #define dasmw(x) \ do { *((unaligned_short *)cp) = (unsigned short)(x); cp+=2; } while (0) #define dasmd(x) \ do { *((unaligned_int *)cp) = (unsigned int)(x); cp+=4; } while (0) #define dasmq(x) \ do { *((unaligned_long_long *)cp) = (unsigned long long)(x); cp+=8; } 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) #define dasmq(x) do { dasmd(x); dasmd((x)>>32); } while (0) #endif static unsigned char *dasma_(unsigned char *cp, ptrdiff_t x) { if (sizeof(ptrdiff_t) == 8) dasmq((unsigned long long)x); else dasmd((unsigned int)x); return cp; } #define dasma(x) (cp = dasma_(cp, (x))) /* 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 = DASM_PTR_ADD(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 ((((unsigned)n+128) & -256) != 0) goto wd; else mm[-1] -= 0x40; } /* fallthrough */ case DASM_IMM_S: case DASM_IMM_B: wb: dasmb(n); break; case DASM_IMM_DB: if ((((unsigned)n+128)&-256) == 0) { db: if (!mark) mark = cp; mark[-2] += 2; mark = NULL; goto wb; } else mark = NULL; /* fallthrough */ case DASM_IMM_D: wd: dasmd(n); break; case DASM_IMM_WB: if ((((unsigned)n+128)&-256) == 0) goto db; else mark = NULL; /* fallthrough */ case DASM_IMM_W: dasmw(n); break; case DASM_VREG: { int t = *p++; unsigned char *ex = cp - (t&7); if ((n & 8) && t < 0xa0) { if (*ex & 0x80) ex[1] ^= 0x20 << (t>>6); else *ex ^= 1 << (t>>6); n &= 7; } else if (n & 0x10) { if (*ex & 0x80) { *ex = 0xc5; ex[1] = (ex[1] & 0x80) | ex[2]; ex += 2; } while (++ex < cp) ex[-1] = *ex; if (mark) mark--; cp--; n &= 7; } if (t >= 0xc0) n <<= 4; else if (t >= 0x40) n <<= 3; else if (n == 4 && t < 0x20) { cp[-1] ^= n; *cp++ = 0x20; } cp[-1] ^= n; break; } case DASM_REL_LG: p++; if (n >= 0) goto rel_pc; b++; n = (int)(ptrdiff_t)D->globals[-n]; /* fallthrough */ case DASM_REL_A: rel_a: n -= (unsigned 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) { dasma((ptrdiff_t)D->globals[-n]); break; } /* fallthrough */ case DASM_IMM_PC: { int *pb = DASM_POS2PTR(D, n); dasma(*pb < 0 ? (ptrdiff_t)pb[1] : (*pb + (ptrdiff_t)base)); break; } 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++; /* fallthrough */ 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