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519 lines
15 KiB
519 lines
15 KiB
/*
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** DynASM ARM64 encoding engine.
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** Copyright (C) 2005-2017 Mike Pall. All rights reserved.
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** Released under the MIT license. See dynasm.lua for full copyright notice.
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*/
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#include <stddef.h>
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#include <stdarg.h>
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#include <string.h>
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#include <stdlib.h>
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#define DASM_ARCH "arm64"
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#ifndef DASM_EXTERN
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#define DASM_EXTERN(a,b,c,d) 0
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#endif
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/* Action definitions. */
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enum {
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DASM_STOP, DASM_SECTION, DASM_ESC, DASM_REL_EXT,
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/* The following actions need a buffer position. */
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DASM_ALIGN, DASM_REL_LG, DASM_LABEL_LG,
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/* The following actions also have an argument. */
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DASM_REL_PC, DASM_LABEL_PC,
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DASM_IMM, DASM_IMM6, DASM_IMM12, DASM_IMM13W, DASM_IMM13X, DASM_IMML,
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DASM__MAX
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};
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/* Maximum number of section buffer positions for a single dasm_put() call. */
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#define DASM_MAXSECPOS 25
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/* DynASM encoder status codes. Action list offset or number are or'ed in. */
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#define DASM_S_OK 0x00000000
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#define DASM_S_NOMEM 0x01000000
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#define DASM_S_PHASE 0x02000000
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#define DASM_S_MATCH_SEC 0x03000000
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#define DASM_S_RANGE_I 0x11000000
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#define DASM_S_RANGE_SEC 0x12000000
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#define DASM_S_RANGE_LG 0x13000000
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#define DASM_S_RANGE_PC 0x14000000
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#define DASM_S_RANGE_REL 0x15000000
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#define DASM_S_UNDEF_LG 0x21000000
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#define DASM_S_UNDEF_PC 0x22000000
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/* Macros to convert positions (8 bit section + 24 bit index). */
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#define DASM_POS2IDX(pos) ((pos)&0x00ffffff)
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#define DASM_POS2BIAS(pos) ((pos)&0xff000000)
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#define DASM_SEC2POS(sec) ((sec)<<24)
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#define DASM_POS2SEC(pos) ((pos)>>24)
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#define DASM_POS2PTR(D, pos) (D->sections[DASM_POS2SEC(pos)].rbuf + (pos))
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/* Action list type. */
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typedef const unsigned int *dasm_ActList;
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/* Per-section structure. */
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typedef struct dasm_Section {
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int *rbuf; /* Biased buffer pointer (negative section bias). */
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int *buf; /* True buffer pointer. */
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size_t bsize; /* Buffer size in bytes. */
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int pos; /* Biased buffer position. */
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int epos; /* End of biased buffer position - max single put. */
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int ofs; /* Byte offset into section. */
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} dasm_Section;
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/* Core structure holding the DynASM encoding state. */
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struct dasm_State {
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size_t psize; /* Allocated size of this structure. */
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dasm_ActList actionlist; /* Current actionlist pointer. */
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int *lglabels; /* Local/global chain/pos ptrs. */
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size_t lgsize;
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int *pclabels; /* PC label chains/pos ptrs. */
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size_t pcsize;
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void **globals; /* Array of globals (bias -10). */
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dasm_Section *section; /* Pointer to active section. */
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size_t codesize; /* Total size of all code sections. */
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int maxsection; /* 0 <= sectionidx < maxsection. */
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int status; /* Status code. */
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dasm_Section sections[1]; /* All sections. Alloc-extended. */
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};
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/* The size of the core structure depends on the max. number of sections. */
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#define DASM_PSZ(ms) (sizeof(dasm_State)+(ms-1)*sizeof(dasm_Section))
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/* Initialize DynASM state. */
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void dasm_init(Dst_DECL, int maxsection)
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{
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dasm_State *D;
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size_t psz = 0;
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int i;
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Dst_REF = NULL;
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DASM_M_GROW(Dst, struct dasm_State, Dst_REF, psz, DASM_PSZ(maxsection));
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D = Dst_REF;
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D->psize = psz;
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D->lglabels = NULL;
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D->lgsize = 0;
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D->pclabels = NULL;
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D->pcsize = 0;
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D->globals = NULL;
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D->maxsection = maxsection;
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for (i = 0; i < maxsection; i++) {
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D->sections[i].buf = NULL; /* Need this for pass3. */
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D->sections[i].rbuf = D->sections[i].buf - DASM_SEC2POS(i);
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D->sections[i].bsize = 0;
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D->sections[i].epos = 0; /* Wrong, but is recalculated after resize. */
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}
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}
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/* Free DynASM state. */
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void dasm_free(Dst_DECL)
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{
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dasm_State *D = Dst_REF;
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int i;
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for (i = 0; i < D->maxsection; i++)
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if (D->sections[i].buf)
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DASM_M_FREE(Dst, D->sections[i].buf, D->sections[i].bsize);
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if (D->pclabels) DASM_M_FREE(Dst, D->pclabels, D->pcsize);
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if (D->lglabels) DASM_M_FREE(Dst, D->lglabels, D->lgsize);
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DASM_M_FREE(Dst, D, D->psize);
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}
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/* Setup global label array. Must be called before dasm_setup(). */
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void dasm_setupglobal(Dst_DECL, void **gl, unsigned int maxgl)
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{
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dasm_State *D = Dst_REF;
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D->globals = gl - 10; /* Negative bias to compensate for locals. */
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DASM_M_GROW(Dst, int, D->lglabels, D->lgsize, (10+maxgl)*sizeof(int));
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}
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/* Grow PC label array. Can be called after dasm_setup(), too. */
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void dasm_growpc(Dst_DECL, unsigned int maxpc)
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{
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dasm_State *D = Dst_REF;
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size_t osz = D->pcsize;
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DASM_M_GROW(Dst, int, D->pclabels, D->pcsize, maxpc*sizeof(int));
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memset((void *)(((unsigned char *)D->pclabels)+osz), 0, D->pcsize-osz);
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}
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/* Setup encoder. */
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void dasm_setup(Dst_DECL, const void *actionlist)
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{
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dasm_State *D = Dst_REF;
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int i;
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D->actionlist = (dasm_ActList)actionlist;
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D->status = DASM_S_OK;
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D->section = &D->sections[0];
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memset((void *)D->lglabels, 0, D->lgsize);
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if (D->pclabels) memset((void *)D->pclabels, 0, D->pcsize);
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for (i = 0; i < D->maxsection; i++) {
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D->sections[i].pos = DASM_SEC2POS(i);
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D->sections[i].ofs = 0;
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}
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}
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#ifdef DASM_CHECKS
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#define CK(x, st) \
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do { if (!(x)) { \
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D->status = DASM_S_##st|(p-D->actionlist-1); return; } } while (0)
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#define CKPL(kind, st) \
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do { if ((size_t)((char *)pl-(char *)D->kind##labels) >= D->kind##size) { \
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D->status = DASM_S_RANGE_##st|(p-D->actionlist-1); return; } } while (0)
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#else
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#define CK(x, st) ((void)0)
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#define CKPL(kind, st) ((void)0)
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#endif
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static int dasm_imm12(unsigned int n)
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{
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if ((n >> 12) == 0)
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return n;
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else if ((n & 0xff000fff) == 0)
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return (n >> 12) | 0x1000;
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else
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return -1;
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}
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static int dasm_ffs(unsigned long long x)
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{
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int n = -1;
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while (x) { x >>= 1; n++; }
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return n;
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}
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static int dasm_imm13(int lo, int hi)
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{
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int inv = 0, w = 64, s = 0xfff, xa, xb;
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unsigned long long n = (((unsigned long long)hi) << 32) | (unsigned int)lo;
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unsigned long long m = 1ULL, a, b, c;
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if (n & 1) { n = ~n; inv = 1; }
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a = n & -n; b = (n+a)&-(n+a); c = (n+a-b)&-(n+a-b);
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xa = dasm_ffs(a); xb = dasm_ffs(b);
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if (c) {
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w = dasm_ffs(c) - xa;
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if (w == 32) m = 0x0000000100000001UL;
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else if (w == 16) m = 0x0001000100010001UL;
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else if (w == 8) m = 0x0101010101010101UL;
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else if (w == 4) m = 0x1111111111111111UL;
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else if (w == 2) m = 0x5555555555555555UL;
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else return -1;
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s = (-2*w & 0x3f) - 1;
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} else if (!a) {
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return -1;
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} else if (xb == -1) {
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xb = 64;
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}
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if ((b-a) * m != n) return -1;
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if (inv) {
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return ((w - xb) << 6) | (s+w+xa-xb);
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} else {
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return ((w - xa) << 6) | (s+xb-xa);
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}
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return -1;
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}
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/* Pass 1: Store actions and args, link branches/labels, estimate offsets. */
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void dasm_put(Dst_DECL, int start, ...)
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{
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va_list ap;
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dasm_State *D = Dst_REF;
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dasm_ActList p = D->actionlist + start;
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dasm_Section *sec = D->section;
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int pos = sec->pos, ofs = sec->ofs;
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int *b;
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if (pos >= sec->epos) {
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DASM_M_GROW(Dst, int, sec->buf, sec->bsize,
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sec->bsize + 2*DASM_MAXSECPOS*sizeof(int));
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sec->rbuf = sec->buf - DASM_POS2BIAS(pos);
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sec->epos = (int)sec->bsize/sizeof(int) - DASM_MAXSECPOS+DASM_POS2BIAS(pos);
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}
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b = sec->rbuf;
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b[pos++] = start;
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va_start(ap, start);
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while (1) {
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unsigned int ins = *p++;
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unsigned int action = (ins >> 16);
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if (action >= DASM__MAX) {
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ofs += 4;
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} else {
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int *pl, n = action >= DASM_REL_PC ? va_arg(ap, int) : 0;
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switch (action) {
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case DASM_STOP: goto stop;
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case DASM_SECTION:
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n = (ins & 255); CK(n < D->maxsection, RANGE_SEC);
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D->section = &D->sections[n]; goto stop;
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case DASM_ESC: p++; ofs += 4; break;
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case DASM_REL_EXT: break;
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case DASM_ALIGN: ofs += (ins & 255); b[pos++] = ofs; break;
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case DASM_REL_LG:
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n = (ins & 2047) - 10; pl = D->lglabels + n;
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/* Bkwd rel or global. */
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if (n >= 0) { CK(n>=10||*pl<0, RANGE_LG); CKPL(lg, LG); goto putrel; }
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pl += 10; n = *pl;
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if (n < 0) n = 0; /* Start new chain for fwd rel if label exists. */
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goto linkrel;
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case DASM_REL_PC:
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pl = D->pclabels + n; CKPL(pc, PC);
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putrel:
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n = *pl;
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if (n < 0) { /* Label exists. Get label pos and store it. */
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b[pos] = -n;
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} else {
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linkrel:
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b[pos] = n; /* Else link to rel chain, anchored at label. */
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*pl = pos;
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}
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pos++;
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break;
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case DASM_LABEL_LG:
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pl = D->lglabels + (ins & 2047) - 10; CKPL(lg, LG); goto putlabel;
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case DASM_LABEL_PC:
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pl = D->pclabels + n; CKPL(pc, PC);
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putlabel:
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n = *pl; /* n > 0: Collapse rel chain and replace with label pos. */
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while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = pos;
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}
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*pl = -pos; /* Label exists now. */
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b[pos++] = ofs; /* Store pass1 offset estimate. */
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break;
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case DASM_IMM:
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CK((n & ((1<<((ins>>10)&31))-1)) == 0, RANGE_I);
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n >>= ((ins>>10)&31);
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#ifdef DASM_CHECKS
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if ((ins & 0x8000))
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CK(((n + (1<<(((ins>>5)&31)-1)))>>((ins>>5)&31)) == 0, RANGE_I);
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else
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CK((n>>((ins>>5)&31)) == 0, RANGE_I);
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#endif
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b[pos++] = n;
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break;
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case DASM_IMM6:
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CK((n >> 6) == 0, RANGE_I);
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b[pos++] = n;
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break;
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case DASM_IMM12:
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CK(dasm_imm12((unsigned int)n) != -1, RANGE_I);
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b[pos++] = n;
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break;
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case DASM_IMM13W:
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CK(dasm_imm13(n, n) != -1, RANGE_I);
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b[pos++] = n;
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break;
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case DASM_IMM13X: {
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int m = va_arg(ap, int);
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CK(dasm_imm13(n, m) != -1, RANGE_I);
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b[pos++] = n;
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b[pos++] = m;
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break;
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}
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case DASM_IMML: {
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#ifdef DASM_CHECKS
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int scale = (p[-2] >> 30);
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CK((!(n & ((1<<scale)-1)) && (unsigned int)(n>>scale) < 4096) ||
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(unsigned int)(n+256) < 512, RANGE_I);
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#endif
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b[pos++] = n;
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break;
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}
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}
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}
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}
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stop:
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va_end(ap);
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sec->pos = pos;
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sec->ofs = ofs;
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}
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#undef CK
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/* Pass 2: Link sections, shrink aligns, fix label offsets. */
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int dasm_link(Dst_DECL, size_t *szp)
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{
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dasm_State *D = Dst_REF;
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int secnum;
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int ofs = 0;
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#ifdef DASM_CHECKS
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*szp = 0;
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if (D->status != DASM_S_OK) return D->status;
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{
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int pc;
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for (pc = 0; pc*sizeof(int) < D->pcsize; pc++)
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if (D->pclabels[pc] > 0) return DASM_S_UNDEF_PC|pc;
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}
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#endif
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{ /* Handle globals not defined in this translation unit. */
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int idx;
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for (idx = 20; idx*sizeof(int) < D->lgsize; idx++) {
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int n = D->lglabels[idx];
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/* Undefined label: Collapse rel chain and replace with marker (< 0). */
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while (n > 0) { int *pb = DASM_POS2PTR(D, n); n = *pb; *pb = -idx; }
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}
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}
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/* Combine all code sections. No support for data sections (yet). */
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for (secnum = 0; secnum < D->maxsection; secnum++) {
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dasm_Section *sec = D->sections + secnum;
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int *b = sec->rbuf;
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int pos = DASM_SEC2POS(secnum);
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int lastpos = sec->pos;
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while (pos != lastpos) {
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dasm_ActList p = D->actionlist + b[pos++];
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while (1) {
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unsigned int ins = *p++;
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unsigned int action = (ins >> 16);
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switch (action) {
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case DASM_STOP: case DASM_SECTION: goto stop;
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case DASM_ESC: p++; break;
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case DASM_REL_EXT: break;
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case DASM_ALIGN: ofs -= (b[pos++] + ofs) & (ins & 255); break;
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case DASM_REL_LG: case DASM_REL_PC: pos++; break;
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case DASM_LABEL_LG: case DASM_LABEL_PC: b[pos++] += ofs; break;
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case DASM_IMM: case DASM_IMM6: case DASM_IMM12: case DASM_IMM13W:
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case DASM_IMML: pos++; break;
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case DASM_IMM13X: pos += 2; break;
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}
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}
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stop: (void)0;
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}
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ofs += sec->ofs; /* Next section starts right after current section. */
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}
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D->codesize = ofs; /* Total size of all code sections */
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*szp = ofs;
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return DASM_S_OK;
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}
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#ifdef DASM_CHECKS
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#define CK(x, st) \
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do { if (!(x)) return DASM_S_##st|(p-D->actionlist-1); } while (0)
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#else
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#define CK(x, st) ((void)0)
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#endif
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/* Pass 3: Encode sections. */
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int dasm_encode(Dst_DECL, void *buffer)
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{
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dasm_State *D = Dst_REF;
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char *base = (char *)buffer;
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unsigned int *cp = (unsigned int *)buffer;
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int secnum;
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/* Encode all code sections. No support for data sections (yet). */
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for (secnum = 0; secnum < D->maxsection; secnum++) {
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dasm_Section *sec = D->sections + secnum;
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int *b = sec->buf;
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int *endb = sec->rbuf + sec->pos;
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while (b != endb) {
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dasm_ActList p = D->actionlist + *b++;
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while (1) {
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unsigned int ins = *p++;
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unsigned int action = (ins >> 16);
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int n = (action >= DASM_ALIGN && action < DASM__MAX) ? *b++ : 0;
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switch (action) {
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case DASM_STOP: case DASM_SECTION: goto stop;
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case DASM_ESC: *cp++ = *p++; break;
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case DASM_REL_EXT:
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n = DASM_EXTERN(Dst, (unsigned char *)cp, (ins&2047), !(ins&2048));
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goto patchrel;
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case DASM_ALIGN:
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ins &= 255; while ((((char *)cp - base) & ins)) *cp++ = 0xe1a00000;
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break;
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case DASM_REL_LG:
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CK(n >= 0, UNDEF_LG);
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case DASM_REL_PC:
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CK(n >= 0, UNDEF_PC);
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n = *DASM_POS2PTR(D, n) - (int)((char *)cp - base) + 4;
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patchrel:
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if (!(ins & 0xf800)) { /* B, BL */
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CK((n & 3) == 0 && ((n+0x08000000) >> 28) == 0, RANGE_REL);
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cp[-1] |= ((n >> 2) & 0x03ffffff);
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} else if ((ins & 0x800)) { /* B.cond, CBZ, CBNZ, LDR* literal */
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CK((n & 3) == 0 && ((n+0x00100000) >> 21) == 0, RANGE_REL);
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cp[-1] |= ((n << 3) & 0x00ffffe0);
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} else if ((ins & 0x3000) == 0x2000) { /* ADR */
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CK(((n+0x00100000) >> 21) == 0, RANGE_REL);
|
|
cp[-1] |= ((n << 3) & 0x00ffffe0) | ((n & 3) << 29);
|
|
} else if ((ins & 0x3000) == 0x3000) { /* ADRP */
|
|
cp[-1] |= ((n >> 9) & 0x00ffffe0) | (((n >> 12) & 3) << 29);
|
|
} else if ((ins & 0x1000)) { /* TBZ, TBNZ */
|
|
CK((n & 3) == 0 && ((n+0x00008000) >> 16) == 0, RANGE_REL);
|
|
cp[-1] |= ((n << 3) & 0x0007ffe0);
|
|
}
|
|
break;
|
|
case DASM_LABEL_LG:
|
|
ins &= 2047; if (ins >= 20) D->globals[ins-10] = (void *)(base + n);
|
|
break;
|
|
case DASM_LABEL_PC: break;
|
|
case DASM_IMM:
|
|
cp[-1] |= (n & ((1<<((ins>>5)&31))-1)) << (ins&31);
|
|
break;
|
|
case DASM_IMM6:
|
|
cp[-1] |= ((n&31) << 19) | ((n&32) << 26);
|
|
break;
|
|
case DASM_IMM12:
|
|
cp[-1] |= (dasm_imm12((unsigned int)n) << 10);
|
|
break;
|
|
case DASM_IMM13W:
|
|
cp[-1] |= (dasm_imm13(n, n) << 10);
|
|
break;
|
|
case DASM_IMM13X:
|
|
cp[-1] |= (dasm_imm13(n, *b++) << 10);
|
|
break;
|
|
case DASM_IMML: {
|
|
int scale = (p[-2] >> 30);
|
|
cp[-1] |= (!(n & ((1<<scale)-1)) && (unsigned int)(n>>scale) < 4096) ?
|
|
((n << (10-scale)) | 0x01000000) : ((n & 511) << 12);
|
|
break;
|
|
}
|
|
default: *cp++ = ins; break;
|
|
}
|
|
}
|
|
stop: (void)0;
|
|
}
|
|
}
|
|
|
|
if (base + D->codesize != (char *)cp) /* Check for phase errors. */
|
|
return DASM_S_PHASE;
|
|
return DASM_S_OK;
|
|
}
|
|
#undef CK
|
|
|
|
/* 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_LG|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|(D->section-D->sections);
|
|
return D->status;
|
|
}
|
|
#endif
|
|
|