/* src/vm/jit/trap.cpp - hardware traps
- Copyright (C) 2008
+ Copyright (C) 2008, 2009
CACAOVM - Verein zur Foerderung der freien virtuellen Maschine CACAO
Copyright (C) 2009 Theobroma Systems Ltd.
*/
void trap_init(void)
{
-#if !(defined(__ARM__) && defined(__LINUX__))
- /* On arm-linux the first memory page can't be mmap'ed, as it
- contains the exception vectors. */
-
- int pagesize;
-
- /* mmap a memory page at address 0x0, so our hardware-exceptions
- work. */
-
- pagesize = os::getpagesize();
+ TRACESUBSYSTEMINITIALIZATION("trap_init");
- (void) os::mmap_anonymous(NULL, pagesize, PROT_NONE, MAP_PRIVATE | MAP_FIXED);
-#endif
+ /* If requested we mmap a memory page at address 0x0,
+ so our hardware-exceptions work. */
- TRACESUBSYSTEMINITIALIZATION("trap_init");
+ if (opt_AlwaysMmapFirstPage) {
+ int pagesize = os::getpagesize();
+ (void) os::mmap_anonymous(NULL, pagesize, PROT_NONE, MAP_PRIVATE | MAP_FIXED);
+ }
#if !defined(TRAP_INSTRUCTION_IS_LOAD)
# error TRAP_INSTRUCTION_IS_LOAD is not defined in your md-trap.h
stackframeinfo_t sfi;
trapinfo_t trp;
- // Prevent compiler warnings.
- java_handle_t* o = NULL;
- methodinfo* m = NULL;
-
#if !defined(NDEBUG)
// Sanity checking the XPC.
if (xpc == NULL)
/* Do some preparations before we enter the nativeworld. */
/* BEFORE: creating stackframeinfo */
+ // Prevent compiler warnings.
+ int32_t index = 0;
+ java_handle_t* o = NULL;
+ methodinfo* m = NULL;
+
switch (type) {
+ case TRAP_ArrayIndexOutOfBoundsException:
+ /* Get the index into the array causing the exception. */
+
+ index = (int32_t) val;
+ break;
+
case TRAP_ClassCastException:
/* Wrap the value into a handle, as it is a reference. */
/* Get resulting exception (or pointer to compiled method). */
- int32_t index;
java_handle_t* p;
void* entry;
+ bool was_patched;
+#if defined(ENABLE_REPLACEMENT)
+ bool was_replaced;
+#endif
switch (type) {
case TRAP_NullPointerException:
break;
case TRAP_ArrayIndexOutOfBoundsException:
- index = (int32_t) val;
p = exceptions_new_arrayindexoutofboundsexception(index);
break;
break;
case TRAP_PATCHER:
+ p = NULL;
#if defined(ENABLE_REPLACEMENT)
- if (replace_me_wrapper((uint8_t*) xpc, context)) {
- p = NULL;
+ was_replaced = replace_handler((uint8_t*) xpc, &es);
+ if (was_replaced)
break;
- }
#endif
- p = patcher_handler((uint8_t*) xpc);
+ was_patched = patcher_handler((uint8_t*) xpc);
break;
case TRAP_COMPILER:
- entry = jit_compile_handle(m, sfi.pv, ra, (void*) val);
p = NULL;
+ entry = jit_compile_handle(m, sfi.pv, ra, (void*) val);
break;
-#if defined(ENABLE_REPLACEMENT)
+#if defined(__I386__) && defined(ENABLE_REPLACEMENT)
+# warning Port the below stuff to use the patching subsystem.
case TRAP_COUNTDOWN:
-# if defined(__I386__)
- replace_me_wrapper((uint8_t*) xpc - 13, context);
-# endif
p = NULL;
+ (void) replace_handler((uint8_t*) xpc - 13, &es);
break;
#endif
goto trap_handle_exception;
case TRAP_PATCHER:
+#if defined(ENABLE_REPLACEMENT)
+ // If on-stack-replacement suceeded, we are not allowed to touch
+ // the execution state. We assume that there was no exception.
+
+ if (was_replaced) {
+ assert(exceptions_get_exception() == NULL);
+ break;
+ }
+#endif
+
// The normal case for a patcher trap is to continue execution at
// the trap instruction. On some archs the PC may point after the
// trap instruction, so we reset it here.
+ if (was_patched) {
+ assert(exceptions_get_exception() == NULL);
+ es.pc = (uint8_t *) (uintptr_t) xpc;
+ break;
+ }
+
+ // In case patching was not successful, we try to fetch the pending
+ // exception here.
+
+ p = exceptions_get_and_clear_exception();
+
+ // If there is no pending exception, we continue execution behind
+ // the position still in need of patching. Normally this would
+ // indicate an error in the patching subsystem, but others might
+ // want to piggyback patchers and we want to be able to provide
+ // "reusable trap points" and avoid inifinite loops here. This is
+ // especially useful to implement breakpoints or profiling points
+ // of any kind. So before changing the trap logic, think about
+ // utilizing the patching subsystem on your quest. :)
+
if (p == NULL) {
+#if !defined(NDEBUG)
+ if (opt_PrintWarnings)
+ log_println("trap_handle: Detected reusable trap at %p", xpc);
+#endif
es.pc = (uint8_t *) (uintptr_t) xpc;
+ es.pc += REPLACEMENT_PATCH_SIZE;
break;
}
trap_handle_exception:
default:
if (p != NULL) {
+#if defined(__X86_64__)
+ // Perform stack unwinding for exceptions on execution state.
+ es.pc = (uint8_t *) (uintptr_t) xpc;
+ es.pv = (uint8_t *) (uintptr_t) sfi.pv;
+ executionstate_unwind_exception(&es, p);
+
+ // Pass the exception object to the exception handler.
+ es.intregs[REG_ITMP1_XPTR] = (uintptr_t) LLNI_DIRECT(p);
+#else
es.intregs[REG_ITMP1_XPTR] = (uintptr_t) LLNI_DIRECT(p);
es.intregs[REG_ITMP2_XPC] = (uintptr_t) xpc;
es.pc = (uint8_t *) (uintptr_t) asm_handle_exception;
+#endif
}
}