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DynASM/arm64: support 64-bit jump table

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Similar to DynASM/x86[1], this patch allows the creation of 64-bit jump
tables. A new mapping entry '.addr' is introduced and its parameter can
be either variables or the references of pc/global/local labels.

Example:

```
  |  adr x0, >1
  |  ldr x2, [x0, x1]
  |  br x2

  |.jmp_table
  |.align 8
  |1:
  |  .addr &addr
  |  .addr >2
  |  .addr <1
  |  .addr =>pcexpr
  |  .addr ->label

```

[1]. https://github.com/LuaJIT/LuaJIT/pull/683

Change-Id: I6006afb28b2121052afa75fed474269f2e50ab3c
This commit is contained in:
Hao Sun 2021-04-27 11:37:09 +03:00 committed by Dmitry Stogov
parent a59fba279a
commit a9ffa6656c
2 changed files with 51 additions and 9 deletions
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36
dynasm/dasm_arm64.h
View File

@ -19,10 +19,10 @@
enum {
DASM_STOP, DASM_SECTION, DASM_ESC, DASM_REL_EXT,
/* The following actions need a buffer position. */
DASM_ALIGN, DASM_REL_LG, DASM_LABEL_LG,
DASM_ALIGN, DASM_REL_LG, DASM_LABEL_LG, DASM_ADDR_LG,
/* The following actions also have an argument. */
DASM_REL_PC, DASM_LABEL_PC,
DASM_IMM, DASM_IMM6, DASM_IMM12, DASM_IMM13W, DASM_IMM13X, DASM_IMML,
DASM_REL_PC, DASM_LABEL_PC, DASM_ADDR_PC,
DASM_IMM, DASM_IMM6, DASM_IMM12, DASM_IMM13W, DASM_IMM13X, DASM_IMML, DASM_IMM_PC,
DASM_VREG,
DASM__MAX
};
@ -251,14 +251,14 @@ void dasm_put(Dst_DECL, int start, ...)
case DASM_ESC: p++; ofs += 4; break;
case DASM_REL_EXT: break;
case DASM_ALIGN: ofs += (ins & 255); b[pos++] = ofs; break;
case DASM_REL_LG:
case DASM_REL_LG: case DASM_ADDR_LG:
n = (ins & 2047) - 10; pl = D->lglabels + n;
/* Bkwd rel or global. */
if (n >= 0) { CK(n>=10||*pl<0, RANGE_LG); CKPL(lg, LG); goto putrel; }
pl += 10; n = *pl;
if (n < 0) n = 0; /* Start new chain for fwd rel if label exists. */
goto linkrel;
case DASM_REL_PC:
case DASM_REL_PC: case DASM_ADDR_PC:
pl = D->pclabels + n; CKPL(pc, PC);
putrel:
n = *pl;
@ -312,6 +312,12 @@ void dasm_put(Dst_DECL, int start, ...)
b[pos++] = m;
break;
}
case DASM_IMM_PC: {
int m = va_arg(ap, int);
b[pos++] = n;
b[pos++] = m;
break;
}
case DASM_IMML: {
#ifdef DASM_CHECKS
int scale = (ins & 3);
@ -378,11 +384,11 @@ int dasm_link(Dst_DECL, size_t *szp)
case DASM_ESC: p++; break;
case DASM_REL_EXT: break;
case DASM_ALIGN: ofs -= (b[pos++] + ofs) & (ins & 255); break;
case DASM_REL_LG: case DASM_REL_PC: pos++; break;
case DASM_REL_LG: case DASM_ADDR_LG: case DASM_REL_PC: case DASM_ADDR_PC: pos++; break;
case DASM_LABEL_LG: case DASM_LABEL_PC: b[pos++] += ofs; break;
case DASM_IMM: case DASM_IMM6: case DASM_IMM12: case DASM_IMM13W:
case DASM_IMML: case DASM_VREG: pos++; break;
case DASM_IMM13X: pos += 2; break;
case DASM_IMM13X: case DASM_IMM_PC: pos += 2; break;
}
}
stop: (void)0;
@ -421,6 +427,7 @@ int dasm_encode(Dst_DECL, void *buffer)
while (1) {
unsigned int ins = *p++;
unsigned int action = (ins >> 16);
unsigned long long addr = 0;
int n = (action >= DASM_ALIGN && action < DASM__MAX) ? *b++ : 0;
switch (action) {
case DASM_STOP: case DASM_SECTION: goto stop;
@ -461,6 +468,17 @@ int dasm_encode(Dst_DECL, void *buffer)
ins &= 2047; if (ins >= 20) D->globals[ins-10] = (void *)(base + n);
break;
case DASM_LABEL_PC: break;
case DASM_ADDR_LG:
if (n < 0) {
addr = (unsigned long long)D->globals[-n];
goto patchaddr;
}
case DASM_ADDR_PC:
addr = (unsigned long long)(*DASM_POS2PTR(D, n) + base);
patchaddr:
cp[-2] = (unsigned int)(addr);
cp[-1] = (unsigned int)(addr >> 32);
break;
case DASM_IMM:
cp[-1] |= (n & ((1<<((ins>>5)&31))-1)) << (ins&31);
break;
@ -473,6 +491,10 @@ int dasm_encode(Dst_DECL, void *buffer)
case DASM_IMM13W:
cp[-1] |= (dasm_imm13(n, n) << 10);
break;
case DASM_IMM_PC:
cp[-2] = (unsigned int)(n);
cp[-1] = (unsigned int)(*b++);
break;
case DASM_IMM13X:
cp[-1] |= (dasm_imm13(n, *b++) << 10);
break;

24
dynasm/dasm_arm64.lua
View File

@ -38,8 +38,8 @@ local wline, werror, wfatal, wwarn
-- CHECK: Keep this in sync with the C code!
local action_names = {
"STOP", "SECTION", "ESC", "REL_EXT",
"ALIGN", "REL_LG", "LABEL_LG",
"REL_PC", "LABEL_PC", "IMM", "IMM6", "IMM12", "IMM13W", "IMM13X", "IMML",
"ALIGN", "REL_LG", "LABEL_LG", "ADDR_LG",
"REL_PC", "LABEL_PC", "ADDR_PC", "IMM", "IMM6", "IMM12", "IMM13W", "IMM13X", "IMML", "IMM_PC",
"VREG",
}
@ -1068,6 +1068,26 @@ map_op[".long_*"] = function(params)
end
end
-- Pseudo-opcodes for jump table entry.
map_op[".addr_1"] = function(params)
if not params then return "&addr | >label | <label | ->label | =>label" end
if secpos+1 > maxsecpos then wflush() end
local prefix = sub(params[1], 1, 1)
if prefix == "&" then
wputw(0)
wputw(0)
local imm = match(params[1], "^&(.*)$")
waction("IMM_PC", 0, format("(unsigned int)(unsigned long long)(%s)", imm))
actargs[#actargs+1] = format("(unsigned int)((unsigned long long)(%s)>>32)", imm)
else
local mode, n, s = parse_label(params[1], false)
if mode == "EXT" then werror("not support extern label reference") end
wputw(0)
wputw(0)
waction("ADDR_"..mode, n, s, 1)
end
end
-- Alignment pseudo-opcode.
map_op[".align_1"] = function(params)
if not params then return "numpow2" end