gh-mirror/mikepaul-LuaJIT
1
0
Fork 0
mirror of https://github.com/LuaJIT/LuaJIT.git synced 2025-02-07 23:24:09 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

ARM: Generalize machine code co-location. ARM has a +-32MB range.

Browse Source
This commit is contained in:
Mike Pall 2011-05-16 02:29:44 +02:00
parent 58f38c254b
commit be73a96751
1 changed files with 26 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
src/lj_mcode.c
View File

@ -156,23 +156,43 @@ static void mcode_protect(jit_State *J, int prot)
/* -- MCode area allocation ----------------------------------------------- */
#if LJ_64
#if LJ_TARGET_X64
#define mcode_validptr(p) ((p) && (uintptr_t)(p) < (uintptr_t)1<<47)
#else
#define mcode_validptr(p) ((p) && (uintptr_t)(p) < 0xffff0000)
#endif
#if LJ_TARGET_X64
#define MCODE_JUMPRANGE 31
#elif LJ_TARGET_ARM
#define MCODE_JUMPRANGE 26
#else
#define MCODE_JUMPRANGE 32
#endif
#if MCODE_JUMPRANGE == 32
/* All 32 bit memory addresses are reachable by relative jumps. */
#define mcode_alloc(J, sz) mcode_alloc_at((J), 0, (sz), MCPROT_GEN)
#else
/* Get memory within relative jump distance of our code in 64 bit mode. */
static void *mcode_alloc(jit_State *J, size_t sz)
{
/* Target an address in the static assembler code (64K aligned).
** Try addresses within a distance of target-1GB+1MB .. target+1GB-1MB.
** Try addresses within a distance of target-range/2+1MB..target+range/2-1MB.
*/
uintptr_t target = (uintptr_t)(void *)lj_vm_exit_handler & ~(uintptr_t)0xffff;
const uintptr_t range = (1u<<31) - (1u << 21);
const uintptr_t range = (1u << MCODE_JUMPRANGE) - (1u << 21);
/* First try a contiguous area below the last one. */
uintptr_t hint = (uintptr_t)J->mcarea - sz;
uintptr_t hint = J->mcarea ? (uintptr_t)J->mcarea - sz : 0;
int i;
for (i = 0; i < 32; i++) { /* 32 attempts ought to be enough ... */
if (hint && hint < (uintptr_t)1<<47) {
if (mcode_validptr(hint)) {
void *p = mcode_alloc_at(J, hint, sz, MCPROT_GEN);
if (p && (uintptr_t)p < (uintptr_t)1<<47) {
if (mcode_validptr(p)) {
if ((uintptr_t)p + sz - target < range || target - (uintptr_t)p < range)
return p;
mcode_free(J, p, sz); /* Free badly placed area. */
@ -188,11 +208,6 @@ static void *mcode_alloc(jit_State *J, size_t sz)
return NULL;
}
#else
/* All 32 bit memory addresses are reachable by relative jumps on x86. */
#define mcode_alloc(J, sz) mcode_alloc_at((J), 0, (sz), MCPROT_GEN)
#endif
/* -- MCode area management ----------------------------------------------- */