Contact: cacao@cacaojvm.org
Authors: Christian Thalinger
+ Edwin Steiner
- Changes: Edwin Steiner
-
- $Id: md.c 4654 2006-03-19 19:46:11Z edwin $
+ $Id: md.c 6180 2006-12-11 23:29:26Z twisti $
*/
#include <assert.h>
#include <unistd.h>
#include <sys/cachectl.h>
-#include <sys/mman.h>
#include "vm/types.h"
#include "toolbox/logging.h"
+#include "vm/exceptions.h"
#include "vm/global.h"
+#include "vm/vm.h"
#include "vm/jit/stacktrace.h"
+
+#if !defined(NDEBUG) && defined(ENABLE_DISASSEMBLER)
#include "vm/options.h" /* XXX debug */
#include "vm/jit/disass.h" /* XXX debug */
+#endif
+
+/* md_codegen_patch_branch *****************************************************
+
+ Back-patches a branch instruction.
+
+*******************************************************************************/
-void docacheflush(u1 *p, long bytelen)
+void md_codegen_patch_branch(codegendata *cd, s4 branchmpc, s4 targetmpc)
{
- u1 *e = p + bytelen;
- long psize = sysconf(_SC_PAGESIZE);
- p -= (long) p & (psize - 1);
- e += psize - ((((long) e - 1) & (psize - 1)) + 1);
- bytelen = e-p;
- mprotect(p, bytelen, PROT_READ | PROT_WRITE | PROT_EXEC);
+ s4 *mcodeptr;
+ s4 mcode;
+ s4 disp; /* branch displacement */
+ s4 lo;
+ s4 hi;
+
+ /* calculate the patch position */
+
+ mcodeptr = (s4 *) (cd->mcodebase + branchmpc);
+
+ /* get the instruction before the exception point */
+
+ mcode = mcodeptr[-1];
+
+ /* check for: ori t9,t9,0 */
+
+ if ((mcode >> 16) == 0x3739) {
+ /* Calculate the branch displacement. For jumps we need a
+ displacement relative to PV. */
+
+ disp = targetmpc;
+
+ lo = (short) disp;
+ hi = (short) ((disp - lo) >> 16);
+
+ /* patch the two instructions before the mcodeptr */
+
+ mcodeptr[-2] |= (hi & 0x0000ffff);
+ mcodeptr[-1] |= (lo & 0x0000ffff);
+ }
+ else {
+ /* Calculate the branch displacement. For branches we need a
+ displacement relative and shifted to the branch PC. */
+
+ disp = (targetmpc - branchmpc) >> 2;
+
+ /* On the MIPS we can only branch signed 16-bit instruction words
+ (signed 18-bit = 32KB = +/- 16KB). Check this! */
+
+ if ((disp < (s4) 0xffff8000) || (disp > (s4) 0x00007fff))
+ vm_abort("jump displacement is out of range: %d > +/-%d", disp, 0x00007fff);
+
+ /* patch the branch instruction before the mcodeptr */
+
+ mcodeptr[-1] |= (disp & 0x0000ffff);
+ }
}
}
-/* md_assembler_get_patch_address **********************************************
+/* md_get_method_patch_address *************************************************
Gets the patch address of the currently compiled method. The offset
is extracted from the load instruction(s) before the jump and added
to the right base address (PV or REG_METHODPTR).
+ INVOKESTATIC/SPECIAL:
+
+ dfdeffb8 ld s8,-72(s8)
+ 03c0f809 jalr s8
+ 00000000 nop
+
+ INVOKEVIRTUAL:
+
+ dc990000 ld t9,0(a0)
+ df3e0000 ld s8,0(t9)
+ 03c0f809 jalr s8
+ 00000000 nop
+
+ INVOKEINTERFACE:
+
+ dc990000 ld t9,0(a0)
+ df39ff90 ld t9,-112(t9)
+ df3e0018 ld s8,24(t9)
+ 03c0f809 jalr s8
+ 00000000 nop
+
*******************************************************************************/
-u1 *md_assembler_get_patch_address(u1 *ra, stackframeinfo *sfi, u1 *mptr)
+u1 *md_get_method_patch_address(u1 *ra, stackframeinfo *sfi, u1 *mptr)
{
u4 mcode;
s4 offset;
assert((mcode >> 16) != 0x6739);
offset += (s2) (mcode & 0x0000ffff);
-
- } else {
+ }
+ else {
/* get first instruction (ld) */
mcode = *((u4 *) ra);
#endif
/* in this case we use the passed method pointer */
- pa = mptr + offset;
+ /* return NULL if no mptr was specified (used for replacement) */
+
+ if (mptr == NULL)
+ return NULL;
- } else {
+ pa = mptr + offset;
+ }
+ else {
/* in the normal case we check for a `ld s8,x(s8)' instruction */
#if SIZEOF_VOID_P == 8
}
-/* md_codegen_findmethod *******************************************************
+/* md_codegen_get_pv_from_pc ***************************************************
Machine code:
*******************************************************************************/
-u1 *md_codegen_findmethod(u1 *ra)
+u1 *md_codegen_get_pv_from_pc(u1 *ra)
{
u1 *pv;
u4 mcode;
#endif
offset += (s2) (mcode & 0x0000ffff);
-
- } else {
+ }
+ else {
/* get offset of first instruction (daddiu) */
mcode = *((u4 *) ra);
*******************************************************************************/
-void md_patch_replacement_point(rplpoint *rp)
+void md_patch_replacement_point(codeinfo *code, s4 index, rplpoint *rp,
+ u1 *savedmcode)
{
- u8 mcode;
+ s4 disp;
+ union {
+ u8 both;
+ u4 words[2];
+ } mcode;
+
+ if (index < 0) {
+ /* restore the patched-over instruction */
+ *(u8*)(rp->pc) = *(u8*)(savedmcode);
+ }
+ else {
+ /* save the current machine code */
+ *(u8*)(savedmcode) = *(u8*)(rp->pc);
+
+ /* make machine code for patching */
+
+ disp = ((u4*)code->replacementstubs - (u4*)rp->pc)
+ + index * REPLACEMENT_STUB_SIZE
+ - 1;
- /* save the current machine code */
- mcode = *(u8*)rp->pc;
+ if ((disp < (s4) 0xffff8000) || (disp > (s4) 0x00007fff)) {
+ *exceptionptr =
+ new_internalerror("Jump offset is out of range: %d > +/-%d",
+ disp, 0x00007fff);
+ return;
+ }
- /* write the new machine code */
- *(u8*)(rp->pc) = rp->mcode;
+ /* BR */
+ mcode.words[0] = (((0x04) << 26) | ((0) << 21) | ((0) << 16) | ((disp) & 0xffff));
+ mcode.words[1] = 0; /* NOP in delay slot */
- /* store saved mcode */
- rp->mcode = mcode;
+ /* write the new machine code */
+ *(u8*)(rp->pc) = mcode.both;
+ }
+#if !defined(NDEBUG) && defined(ENABLE_DISASSEMBLER)
{
u1* u1ptr = rp->pc;
DISASSINSTR(u1ptr);
DISASSINSTR(u1ptr);
fflush(stdout);
}
+#endif
/* flush instruction cache */
md_icacheflush(rp->pc,2*4);
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