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/* * gcj-except.c * * Copyright (c) 1996, 1997, 1998 * Transvirtual Technologies, Inc. All rights reserved. * * See the file "license.terms" for information on usage and redistribution * of this file. * * Written by Godmar Back */#include "config.h"#if defined(HAVE_GCJ_SUPPORT) && defined(JIT3)#include "config-std.h"#include "config-setjmp.h"#include "gtypes.h"#include "debug.h"#include "classMethod.h"#include "stackTrace.h"#include "thread.h"#include "gcj-except.h"#include "stringSupport.h"#include "lookup.h"#include "soft.h"#include "access.h"#include "md.h"#include "exception.h"#include "gcj.h"/* from compat-include */#include "gansidecl.h"#include "eh-common.h"#include "frame.h"/* Language specific exception information */typedef struct _gcjException { __eh_info eh_info; Hjava_lang_Class* eclass; Hjava_lang_Throwable* eobj;} gcjException;static struct frame_state *gcjStateForReplacement(void *pc_target, struct frame_state *callee_state, struct frame_state *state_in);/* From libgcc2.c */extern frame_state * (*__frame_state_for_func)(void *, frame_state *, frame_state *);extern void (*__terminate_func)(void);extern void __throw(void);extern void **__get_eh_info(void);extern short __get_eh_table_language (void *table);/* * Return true if the pc passed is within the trampoline function * Since the trampoline is written in assembler, we must handle it * manually when unwinding the stack. XXX Find a better way. */static int arch_is_trampoline_frame(void *pc) {extern void (*f)(void) asm(C_FUNC_NAME(i386_do_fixup_trampoline));return ((char*)pc == ((char*)&f + 4));}/* * See if the exception info matches the given class. * This function is invoked by __throw as it tries to find a * matching exception handler. * * Compare _Jv_type_matcher in exception.cc */static void *gcjMatcher(gcjException* einfo, void* match_info, void* exception_table){DBG(GCJ,dprintf(__FUNCTION__": match_info %p\n", match_info); )if (__get_eh_table_language (exception_table) != EH_LANG_Java) {DBG(GCJ,dprintf(__FUNCTION__":not java, ignored\n"); )return (0);}if (match_info != 0) {errorInfo info;Hjava_lang_Class *kclass = gcjFindMatchClass(match_info, &info);if (kclass == 0) {DBG(GCJ,dprintf("%s: kclass is null\n", __FUNCTION__); )throwError(&info);/* XXX does that work? */}assert(kclass);DBG(GCJ,dprintf("%s: matching class `%s'\n", __FUNCTION__, CLASS_CNAME(kclass)); )if (!soft_instanceof(kclass, (Hjava_lang_Object*)einfo->eobj)) {return (0);}}/* else no match_info is given, must mean its always matches !? */return (einfo->eobj);}/* * Return the exception object. * * gcc's exception system has a clumsy way of passing the exception * object. * It is done out-of-band using thread-specific information * that's accessed in the exception handler. * * We must set this information before we throw. */void*_Jv_exception_info(void){void *obj;gcjException *einf = *(__get_eh_info());if (einf == 0) {dprintf("Attempt to catch an exception ""before throwing one. This is bad.\n");KAFFEVM_ABORT();}obj = einf->eobj;einf->eobj = 0;return (obj);}/* * Invoked when gcj can't find an exception handler */voidgcjUnhandledException(void){unhandledException(_Jv_exception_info());}static voidgcjExceptionInit(void){static int inited = 0;if (inited == 0) {__terminate_func = gcjUnhandledException;__frame_state_for_func = gcjStateForReplacement;inited = 1;}}/* * GCJ code wants to throw an exception. */void_Jv_Throw(void* obj){gcjException *einf;if (obj == 0) {obj = NullPointerException;}einf = *(__get_eh_info());/* Allocate on first invocation (for this thread) */if (einf == 0) {einf = /* XXX KMALLOC */ calloc(1, sizeof *einf);*(__get_eh_info()) = einf;gcjExceptionInit();}einf->eh_info.match_function = (__eh_matcher) gcjMatcher;einf->eh_info.language = EH_LANG_Java;einf->eh_info.version = 1;einf->eobj = (Hjava_lang_Throwable*)obj;einf->eclass = OBJECT_CLASS(&(einf->eobj)->base);DBG(GCJ,dprintf("invoking __throw: obj@%p class=`%s'\n", obj, CLASS_CNAME(einf->eclass)); )/* send the exception off to gcc and pray */__throw();}void /* ARGUSED */kenvThrowBadArrayIndex(int idx){_Jv_Throw(ArrayIndexOutOfBoundsException);}/* * This is what gcc's internal frame_state structure looks like * it is defined in frame.h * * * typedef struct frame_state * { * void *cfa; * void *eh_ptr; * long cfa_offset; * long args_size; * long reg_or_offset[DWARF_FRAME_REGISTERS+1]; * unsigned short cfa_reg; * unsigned short retaddr_column; * char saved[DWARF_FRAME_REGISTERS+1]; * } frame_state; * */voiddumpFS(char *label, struct frame_state *s){int i;dprintf("%s: frame_state %p\n", label, s);dprintf("cfa = %p, eh_ptr = %p, ""cfa_offset = %ld, args_size = %ld\n",s->cfa, s->eh_ptr, s->cfa_offset, s->args_size);for (i = 0; i char *w = s->saved[i] == REG_SAVED_OFFSET ? "Off" : s->saved[i] == REG_SAVED_REG ? "Reg" : "Und";if (s->saved[i] == 0) {/* skip unsaved ones, they're not * that interesting */continue;}dprintf("{%2d: %s %4ld}%c", i, w, s->reg_or_offset[i],((i+1) % 8 == 0) ? '\n' : ' ');}dprintf("\ncfa_reg = %d, retaddr_column = %d\n---- eofs ----\n",s->cfa_reg, s->retaddr_column);fflush(stderr);}/* * This method is our hook into the exception handling system in eh.c * * NB: this method is invoked twice for each stack frame *//* The original documentation for frame_state_for says: *//* Called from __throw to find the registers to restore for a given PC_TARGET. The caller should allocate a local variable of `struct frame_state' (declared in frame.h) and pass its address to STATE_IN. Returns NULL on failure, otherwise returns STATE_IN. */static struct frame_state *gcjStateForReplacement(void *pc_target, struct frame_state *callee_state, struct frame_state *state_in){int i, n;int is_trampoline = 0;Method *meth;struct kaffe_frame_descriptor frame_desc[DWARF_FRAME_REGISTERS];stackTraceInfo frame;gcjException *einf = *(__get_eh_info());/* First, check whether it's a JNI method */if (!IS_IN_JNI_RANGE((uintp)pc_target)) {/* otherwise, check if it's a method for which there is * DWARF2 exception information. */frame_state *fs = __frame_state_for(pc_target, state_in);if (fs != 0) {return (fs);}}frame.pc = (uintp)pc_target;frame.fp = (uintp)(*(void**)(callee_state->cfa + CFA_SAVED_OFFSET));frame.meth = (Method*)0; /* not known, not needed, see stackTrace.h */DBG(GCJ, dprintf(__FUNCTION__": unwinding pc=%p fp=%p ccfa=%p + %d (%s)\n", frame.pc, frame.fp, callee_state->cfa, CFA_SAVED_OFFSET,(IS_IN_JNI_RANGE((uintp)pc_target) ? "JNI" : "No JNI")); )/* First attempt to deliver this exception to a handler in * kaffe's jitted code. If that succeeds, we won't return. * Otherwise, we'll have a pointer to the kaffe method that * we need get our state from. * * unwindStackFrame includes actions to be done when unrolling * one stack frame in kaffe/jit, such as unlocking an object if * a method is synchronized */meth = unwindStackFrame(&frame, einf->eobj);if (!meth) {if (arch_is_trampoline_frame(pc_target)) {is_trampoline = 1;} else {DBG(GCJ,dprintf("%s: unknown pc@%p\n", __FUNCTION__, pc_target);)return (0);}}DBG(GCJ,if (!is_trampoline) {dprintf(__FUNCTION__": %s.%s%s framesize is %d\n", CLASS_CNAME(meth->class), meth->name->data, PSIG_DATA(METHOD_PSIG(meth)), meth->framesize);} else {dprintf(__FUNCTION__": hit trampoline\n");} )/* * else tell gcj that there's no handler here and * tell it how to unroll this frame. */memset(state_in, 0, sizeof (*state_in));/* this is a constant that says where we store the return address */state_in->retaddr_column = DWARF_FRAME_RETURN_COLUMN;/* * Setting this to 0 means that this frame has no exception handler * table, hence no handler at all. gcc will accept that. */state_in->eh_ptr = 0;/* which register holds the canonical frame address? Usually sp */state_in->cfa_reg = CFA_REGISTER;/* If we restore the sp, how much do we have to add to get to the * canonical frame address. See layout picture. */state_in->cfa_offset = CFA_OFFSET;/* * How many bytes did the caller have to push to invoke this method * This is the n in "addl $n, esp" after a function call on the x86 */if (!is_trampoline) {state_in->args_size = PSIG_NARGS(METHOD_PSIG(meth));if (!(meth->accflags & ACC_STATIC)) {state_in->args_size++;}state_in->args_size *= 4;} else {state_in->args_size = 0;/* ??? */}/* * For all callee-saved registers (including the cfa register and * the return address register), fill in the offsets at which they're * saved. In a gcj program, this will be frame-specific information. * * In Kaffe with its eager strategy of saving those registers, it * will be relatively constant. */arch_get_frame_description(is_trampoline ? -1 : meth->framesize, frame_desc, &n);for (i = 0; i < n; i++) {int idx = frame_desc[i].idx;state_in->saved[idx] = REG_SAVED_OFFSET;state_in->reg_or_offset[idx] = frame_desc[i].offset;}return (state_in);}#endif