// Functions for Exception Support for Java.
-/* Copyright (C) 1998, 1999 Cygnus Solutions
+/* Copyright (C) 1998, 1999, 2001, 2002, 2006, 2010, 2011
+ Free Software Foundation
This file is part of libgcj.
#include <config.h>
-#include "exception"
#include <stddef.h>
+#include <stdlib.h>
#include <java/lang/Class.h>
#include <java/lang/NullPointerException.h>
-#include <cni.h>
+#include <gnu/gcj/RawData.h>
+#include <gcj/cni.h>
#include <jvm.h>
-// eh-common.h needs gansidecl.h.
-#include "gansidecl.h"
-#include "eh-common.h"
+// unwind-pe.h uses std::abort(), but sometimes we compile libjava
+// without libstdc++-v3. The following hack forces it to use
+// stdlib.h's abort().
+namespace std
+{
+ __attribute__ ((__noreturn__)) void
+ abort ()
+ {
+ ::abort ();
+ }
+}
+#include "unwind.h"
+
+struct alignment_test_struct
+{
+ char space;
+ char end[0] __attribute__((aligned));
+};
-typedef struct {
- __eh_info eh_info;
- void *value;
-} java_eh_info;
+struct java_exception_header
+{
+ /* Cache handler details between Phase 1 and Phase 2. */
+ _Unwind_Ptr landingPad;
+ int handlerSwitchValue;
+ /* The object being thrown. Compiled code expects this to be immediately
+ before the generic exception header. Which is complicated by the fact
+ that _Unwind_Exception is ((aligned)). */
-/* Language-specific EH info pointer, throw routine, and language/version
- info routines. All defined in libgcc2. */
+ char pad[sizeof(jthrowable) < sizeof(alignment_test_struct)
+ ? sizeof(alignment_test_struct) - sizeof(jthrowable) : 0]
+ __attribute__((aligned));
-extern "C" java_eh_info **__get_eh_info ();
-extern "C" void __throw () __attribute__ ((__noreturn__));
-extern "C" short __get_eh_table_version (void *table);
-extern "C" short __get_eh_table_language (void *table);
+ jthrowable value;
+ /* The generic exception header. */
+ _Unwind_Exception unwindHeader;
+};
-extern "C" void * malloc (size_t);
-extern "C" void free (void *);
+#ifdef __ARM_EABI_UNWINDER__
+// This is the exception class we report -- "GNUCJAVA".
+const _Unwind_Exception_Class __gcj_exception_class
+ = {'G', 'N', 'U', 'C', 'J', 'A', 'V', 'A'};
-extern "C" void *
-_Jv_type_matcher (java_eh_info *info, void* match_info,
- void *exception_table)
+static inline java_exception_header *
+get_exception_header_from_ue (_Unwind_Exception *exc)
{
- if (__get_eh_table_language (exception_table) != EH_LANG_Java)
- return NULL;
+ return reinterpret_cast<java_exception_header *>(exc + 1) - 1;
+}
- /* we don't worry about version info yet, there is only one version! */
-
- if (match_info != NULL)
- {
- // The match_info is either a (java::lang::Class*) or
- // match_info is one more than a (Utf8Const*).
- if (sizeof(void*) != sizeof(size_t))
- abort();
- size_t mi = (size_t) match_info;
- if ((mi & 1) != 0)
- match_info = _Jv_FindClass ((Utf8Const*) (mi - 1), NULL);
- if (! _Jv_IsInstanceOf ((jobject) info->value, (jclass) match_info))
- return NULL;
- }
+extern "C" void __cxa_begin_cleanup (_Unwind_Exception*);
+
+#else // !__ARM_EABI_UNWINDER__
+// This is the exception class we report -- "GNUCJAVA".
+const _Unwind_Exception_Class __gcj_exception_class
+= ((((((((_Unwind_Exception_Class) 'G'
+ << 8 | (_Unwind_Exception_Class) 'N')
+ << 8 | (_Unwind_Exception_Class) 'U')
+ << 8 | (_Unwind_Exception_Class) 'C')
+ << 8 | (_Unwind_Exception_Class) 'J')
+ << 8 | (_Unwind_Exception_Class) 'A')
+ << 8 | (_Unwind_Exception_Class) 'V')
+ << 8 | (_Unwind_Exception_Class) 'A');
- return info->value;
+
+static inline java_exception_header *
+get_exception_header_from_ue (_Unwind_Exception *exc)
+{
+ return reinterpret_cast<java_exception_header *>(exc + 1) - 1;
}
+#endif // !__ARM_EABI_UNWINDER__
-/* Compiler hook to return a pointer to java exception object. The value
- is cleared, so if the exception needs to be rethrown, it should be set
- again */
+/* Perform a throw, Java style. Throw will unwind through this call,
+ so there better not be any handlers or exception thrown here. */
-extern "C" void *
-_Jv_exception_info (void)
+extern "C" void
+_Jv_Throw (jthrowable value)
{
- java_eh_info *info = *(__get_eh_info ());
- void *ptr;
+ java_exception_header *xh
+ = static_cast<java_exception_header *>(_Jv_AllocRawObj (sizeof (*xh)));
- if (info == NULL)
- abort ();
+ if (value == NULL)
+ value = new java::lang::NullPointerException ();
+ xh->value = value;
+
+ memcpy (&xh->unwindHeader.exception_class, &__gcj_exception_class,
+ sizeof xh->unwindHeader.exception_class);
+ xh->unwindHeader.exception_cleanup = NULL;
+
+ /* We're happy with setjmp/longjmp exceptions or region-based
+ exception handlers: entry points are provided here for both. */
+#ifdef SJLJ_EXCEPTIONS
+ _Unwind_SjLj_RaiseException (&xh->unwindHeader);
+#else
+ _Unwind_RaiseException (&xh->unwindHeader);
+#endif
+
+ /* If code == _URC_END_OF_STACK, then we reached top of stack without
+ finding a handler for the exception. Since each thread is run in
+ a try/catch, this oughtn't happen. If code is something else, we
+ encountered some sort of heinous lossage from which we could not
+ recover. As is the way of such things, almost certainly we will have
+ crashed before now, rather than actually being able to diagnose the
+ problem. */
+ abort();
+}
- ptr = info->value;
+\f
+#include "unwind-pe.h"
+\f
+struct lsda_header_info
+{
+ _Unwind_Ptr Start;
+ _Unwind_Ptr LPStart;
+ const unsigned char *TType;
+ const unsigned char *action_table;
+ unsigned char ttype_encoding;
+ unsigned char call_site_encoding;
+};
+
+static const unsigned char *
+parse_lsda_header (_Unwind_Context *context, const unsigned char *p,
+ lsda_header_info *info)
+{
+ _uleb128_t tmp;
+ unsigned char lpstart_encoding;
- /* clear the value so another throw is an error */
- info->value = NULL;
+ info->Start = (context ? _Unwind_GetRegionStart (context) : 0);
- return ptr;
-}
+ // Find @LPStart, the base to which landing pad offsets are relative.
+ lpstart_encoding = *p++;
+ if (lpstart_encoding != DW_EH_PE_omit)
+ p = read_encoded_value (context, lpstart_encoding, p, &info->LPStart);
+ else
+ info->LPStart = info->Start;
+ // Find @TType, the base of the handler and exception spec type data.
+ info->ttype_encoding = *p++;
+ if (info->ttype_encoding != DW_EH_PE_omit)
+ {
+#if _GLIBCXX_OVERRIDE_TTYPE_ENCODING
+ /* Older ARM EABI toolchains set this value incorrectly, so use a
+ hardcoded OS-specific format. */
+ info->ttype_encoding = _GLIBCXX_OVERRIDE_TTYPE_ENCODING;
+#endif
+ p = read_uleb128 (p, &tmp);
+ info->TType = p + tmp;
+ }
+ else
+ info->TType = 0;
+ // The encoding and length of the call-site table; the action table
+ // immediately follows.
+ info->call_site_encoding = *p++;
+ p = read_uleb128 (p, &tmp);
+ info->action_table = p + tmp;
-/* Allocate an exception info structure for java. Called the first time
- an exception is thrown. */
+ return p;
+}
-extern "C" void
-_Jv_eh_alloc ()
+static void **
+get_ttype_entry (_Unwind_Context *context, lsda_header_info *info, long i)
{
- /* FIXME: we should use _Jv_AllocBytes here. However, libgcc2
- apparently can sometimes free() this value itself. */
- java_eh_info *p = (java_eh_info *) malloc (sizeof (java_eh_info));
- if (p == 0)
- terminate ();
+ _Unwind_Ptr ptr;
- p->value = 0;
- java_eh_info ** info_ptr = __get_eh_info ();
+ i *= size_of_encoded_value (info->ttype_encoding);
+ read_encoded_value (context, info->ttype_encoding, info->TType - i, &ptr);
- /* There should NOT be an exception info pointer already. */
- if (*info_ptr != NULL)
- abort ();
-
- *info_ptr = p;
+ return reinterpret_cast<void **>(ptr);
}
-/* Deallocate the current exception info structure. Called at shutdown time. */
-
-extern "C" void
-_Jv_eh_free ()
+// Using a different personality function name causes link failures
+// when trying to mix code using different exception handling models.
+#ifdef SJLJ_EXCEPTIONS
+#define PERSONALITY_FUNCTION __gcj_personality_sj0
+#define __builtin_eh_return_data_regno(x) x
+#else
+#define PERSONALITY_FUNCTION __gcj_personality_v0
+#endif
+
+#ifdef __ARM_EABI_UNWINDER__
+
+#define CONTINUE_UNWINDING \
+ do \
+ { \
+ if (__gnu_unwind_frame(ue_header, context) != _URC_OK) \
+ return _URC_FAILURE; \
+ return _URC_CONTINUE_UNWIND; \
+ } \
+ while (0)
+
+extern "C" _Unwind_Reason_Code
+PERSONALITY_FUNCTION (_Unwind_State state,
+ struct _Unwind_Exception* ue_header,
+ struct _Unwind_Context* context)
+#else
+
+#define CONTINUE_UNWINDING return _URC_CONTINUE_UNWIND
+
+extern "C" _Unwind_Reason_Code
+PERSONALITY_FUNCTION (int version,
+ _Unwind_Action actions,
+ _Unwind_Exception_Class exception_class,
+ struct _Unwind_Exception *ue_header,
+ struct _Unwind_Context *context)
+
+#endif
{
- java_eh_info ** info_ptr = __get_eh_info ();
- if (*info_ptr == NULL)
- abort ();
-
- /* FIXME: ideally we should just let the GC handle this. */
- free (*info_ptr);
- *info_ptr = NULL;
-}
+ java_exception_header *xh = get_exception_header_from_ue (ue_header);
+
+ lsda_header_info info;
+ const unsigned char *language_specific_data;
+ const unsigned char *action_record;
+ const unsigned char *p;
+ _Unwind_Ptr landing_pad, ip;
+ int handler_switch_value;
+ bool saw_cleanup;
+ bool saw_handler;
+ bool foreign_exception;
+ int ip_before_insn = 0;
+
+#ifdef __ARM_EABI_UNWINDER__
+ _Unwind_Action actions;
+
+ switch (state & _US_ACTION_MASK)
+ {
+ case _US_VIRTUAL_UNWIND_FRAME:
+ actions = _UA_SEARCH_PHASE;
+ break;
+
+ case _US_UNWIND_FRAME_STARTING:
+ actions = _UA_CLEANUP_PHASE;
+ if (!(state & _US_FORCE_UNWIND)
+ && ue_header->barrier_cache.sp == _Unwind_GetGR(context, 13))
+ actions |= _UA_HANDLER_FRAME;
+ break;
+
+ case _US_UNWIND_FRAME_RESUME:
+ CONTINUE_UNWINDING;
+ break;
+
+ default:
+ std::abort();
+ }
+ actions |= state & _US_FORCE_UNWIND;
+
+ // We don't know which runtime we're working with, so can't check this.
+ // However the ABI routines hide this from us, and we don't actually need
+ // to know.
+ foreign_exception = false;
+
+ // The dwarf unwinder assumes the context structure holds things like the
+ // function and LSDA pointers. The ARM implementation caches these in
+ // the exception header (UCB). To avoid rewriting everything we make the
+ // virtual IP register point at the UCB.
+ ip = (_Unwind_Ptr) ue_header;
+ _Unwind_SetGR(context, 12, ip);
+
+#else
+ // Interface version check.
+ if (version != 1)
+ return _URC_FATAL_PHASE1_ERROR;
+ foreign_exception = exception_class != __gcj_exception_class;
+#endif
+
+ // Shortcut for phase 2 found handler for domestic exception.
+ if (actions == (_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME)
+ && !foreign_exception)
+ {
+ handler_switch_value = xh->handlerSwitchValue;
+ landing_pad = xh->landingPad;
+ goto install_context;
+ }
-/* Perform a throw, Java style. Throw will unwind through this call, so
- there better not be any handlers or exception thrown here. */
+ // FIXME: In Phase 1, record _Unwind_GetIPInfo in xh->obj as a part of
+ // the stack trace for this exception. This will only collect Java
+ // frames, but perhaps that is acceptable.
+ // FIXME2: _Unwind_GetIPInfo is nonsensical for SJLJ, being a call-site
+ // index instead of a PC value. We could perhaps arrange for
+ // _Unwind_GetRegionStart to return context->fc->jbuf[1], which
+ // is the address of the handler label for __builtin_longjmp, but
+ // there is no solution for DONT_USE_BUILTIN_SETJMP.
+
+ language_specific_data = (const unsigned char *)
+ _Unwind_GetLanguageSpecificData (context);
+
+ // If no LSDA, then there are no handlers or cleanups.
+ if (! language_specific_data)
+ CONTINUE_UNWINDING;
+
+ // Parse the LSDA header.
+ p = parse_lsda_header (context, language_specific_data, &info);
+#ifdef HAVE_GETIPINFO
+ ip = _Unwind_GetIPInfo (context, &ip_before_insn);
+#else
+ ip = _Unwind_GetIP (context);
+#endif
+ if (! ip_before_insn)
+ --ip;
+ landing_pad = 0;
+ action_record = 0;
+ handler_switch_value = 0;
+
+#ifdef SJLJ_EXCEPTIONS
+ // The given "IP" is an index into the call-site table, with two
+ // exceptions -- -1 means no-action, and 0 means terminate. But
+ // since we're using uleb128 values, we've not got random access
+ // to the array.
+ if ((int) ip <= 0)
+ return _URC_CONTINUE_UNWIND;
+ else
+ {
+ _uleb128_t cs_lp, cs_action;
+ do
+ {
+ p = read_uleb128 (p, &cs_lp);
+ p = read_uleb128 (p, &cs_action);
+ }
+ while (--ip);
+
+ // Can never have null landing pad for sjlj -- that would have
+ // been indicated by a -1 call site index.
+ landing_pad = cs_lp + 1;
+ if (cs_action)
+ action_record = info.action_table + cs_action - 1;
+ goto found_something;
+ }
+#else
+ // Search the call-site table for the action associated with this IP.
+ while (p < info.action_table)
+ {
+ _Unwind_Ptr cs_start, cs_len, cs_lp;
+ _uleb128_t cs_action;
+
+ // Note that all call-site encodings are "absolute" displacements.
+ p = read_encoded_value (0, info.call_site_encoding, p, &cs_start);
+ p = read_encoded_value (0, info.call_site_encoding, p, &cs_len);
+ p = read_encoded_value (0, info.call_site_encoding, p, &cs_lp);
+ p = read_uleb128 (p, &cs_action);
+
+ // The table is sorted, so if we've passed the ip, stop.
+ if (ip < info.Start + cs_start)
+ p = info.action_table;
+ else if (ip < info.Start + cs_start + cs_len)
+ {
+ if (cs_lp)
+ landing_pad = info.LPStart + cs_lp;
+ if (cs_action)
+ action_record = info.action_table + cs_action - 1;
+ goto found_something;
+ }
+ }
+#endif // SJLJ_EXCEPTIONS
+ // If ip is not present in the table, C++ would call terminate.
+ // ??? It is perhaps better to tweek the LSDA so that no-action
+ // is mapped to no-entry for Java.
+ CONTINUE_UNWINDING;
-/* Initialize an __eh_info structure with this libraries matching info. */
+ found_something:
+ saw_cleanup = false;
+ saw_handler = false;
-extern "C" void
-_Jv_setup_eh_info (__eh_info *)
-{
-}
+ if (landing_pad == 0)
+ {
+ // If ip is present, and has a null landing pad, there are
+ // no cleanups or handlers to be run.
+ }
+ else if (action_record == 0)
+ {
+ // If ip is present, has a non-null landing pad, and a null
+ // action table offset, then there are only cleanups present.
+ // Cleanups use a zero switch value, as set above.
+ saw_cleanup = true;
+ }
+ else
+ {
+ // Otherwise we have a catch handler.
+ _sleb128_t ar_filter, ar_disp;
+
+ while (1)
+ {
+ p = action_record;
+ p = read_sleb128 (p, &ar_filter);
+ read_sleb128 (p, &ar_disp);
+
+ if (ar_filter == 0)
+ {
+ // Zero filter values are cleanups.
+ saw_cleanup = true;
+ }
+
+ // During forced unwinding, we only run cleanups. With a
+ // foreign exception class, we have no class info to match.
+ else if ((actions & _UA_FORCE_UNWIND)
+ || foreign_exception)
+ ;
+
+ else if (ar_filter > 0)
+ {
+ // Positive filter values are handlers.
+
+ void **catch_word = get_ttype_entry (context, &info, ar_filter);
+ jclass catch_type = (jclass)*catch_word;
+
+ // FIXME: This line is a kludge to work around exception
+ // handlers written in C++, which don't yet use indirect
+ // dispatch.
+ if (catch_type == *(void **)&java::lang::Class::class$)
+ catch_type = (jclass)catch_word;
+
+ if (_Jv_IsInstanceOf (xh->value, catch_type))
+ {
+ handler_switch_value = ar_filter;
+ saw_handler = true;
+ break;
+ }
+ }
+ else
+ {
+ // Negative filter values are exception specifications,
+ // which Java does not use.
+ // ??? Perhaps better to make them an index into a table
+ // of null-terminated strings instead of playing games
+ // with Utf8Const+1 as above.
+ abort ();
+ }
+
+ if (ar_disp == 0)
+ break;
+ action_record = p + ar_disp;
+ }
+ }
-extern "C" void
-_Jv_Throw (void *value)
-{
- if (value == NULL)
- value = (void *) new java::lang::NullPointerException ();
- java_eh_info *ehinfo = *(__get_eh_info ());
- if (ehinfo == NULL)
+ if (! saw_handler && ! saw_cleanup)
+ CONTINUE_UNWINDING;
+
+ if (actions & _UA_SEARCH_PHASE)
{
- _Jv_eh_alloc ();
- ehinfo = *(__get_eh_info ());
+ if (! saw_handler)
+ CONTINUE_UNWINDING;
+
+ // For domestic exceptions, we cache data from phase 1 for phase 2.
+ if (! foreign_exception)
+ {
+ xh->handlerSwitchValue = handler_switch_value;
+ xh->landingPad = landing_pad;
+ }
+ return _URC_HANDLER_FOUND;
}
- ehinfo->eh_info.match_function = (__eh_matcher) _Jv_type_matcher;
- ehinfo->eh_info.language = EH_LANG_Java;
- ehinfo->eh_info.version = 1;
- ehinfo->value = value;
- __throw();
+
+ install_context:
+ _Unwind_SetGR (context, __builtin_eh_return_data_regno (0),
+ (_Unwind_Ptr) &xh->unwindHeader);
+ _Unwind_SetGR (context, __builtin_eh_return_data_regno (1),
+ handler_switch_value);
+ _Unwind_SetIP (context, landing_pad);
+#ifdef __ARM_EABI_UNWINDER__
+ if (saw_cleanup)
+ __cxa_begin_cleanup(ue_header);
+#endif
+ return _URC_INSTALL_CONTEXT;
}
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