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authorrth <rth@138bc75d-0d04-0410-961f-82ee72b054a4>2001-03-28 11:04:51 +0000
committerrth <rth@138bc75d-0d04-0410-961f-82ee72b054a4>2001-03-28 11:04:51 +0000
commitdf4b504cae7856b864a073ab9e6e61cf2ad23a97 (patch)
treea923c8785a06871784c5177530130063c4925f5a /libjava/exception.cc
parentd3ab49408bd5b876d10076caea78dc81a5f85dd7 (diff)
downloadgcc-df4b504cae7856b864a073ab9e6e61cf2ad23a97.tar.gz
IA-64 ABI Exception Handling.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@40924 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'libjava/exception.cc')
-rw-r--r--libjava/exception.cc620
1 files changed, 492 insertions, 128 deletions
diff --git a/libjava/exception.cc b/libjava/exception.cc
index fdbfc420c0e..41f7676063e 100644
--- a/libjava/exception.cc
+++ b/libjava/exception.cc
@@ -1,6 +1,6 @@
// Functions for Exception Support for Java.
-/* Copyright (C) 1998, 1999 Free Software Foundation
+/* Copyright (C) 1998, 1999, 2001 Free Software Foundation
This file is part of libgcj.
@@ -18,182 +18,546 @@ details. */
#include <gcj/cni.h>
#include <jvm.h>
-// eh-common.h needs gansidecl.h.
-#include "gansidecl.h"
-#include "eh-common.h"
-
-typedef struct {
- __eh_info eh_info;
- jthrowable value;
-} java_eh_info;
+#include "unwind.h"
+
+// More nastiness: the GC wants to define TRUE and FALSE. We don't
+// need the Java definitions (themselves a hack), so we undefine them.
+#undef TRUE
+#undef FALSE
-/* Language-specific EH info pointer, throw routine, and language/version
- info routines. All defined in libgcc2. */
+extern "C"
+{
+#include <gc_priv.h>
+#include <gc_mark.h>
+#include <include/gc_gcj.h>
+};
-extern "C" java_eh_info **__get_eh_info ();
-extern "C" void __throw () __attribute__ ((__noreturn__));
-extern "C" void __sjthrow () __attribute__ ((__noreturn__));
-extern "C" short __get_eh_table_version (void *table);
-extern "C" short __get_eh_table_language (void *table);
-extern "C" void *__get_eh_context ();
+
+struct alignment_test_struct
+{
+ char space;
+ char end[0] __attribute__((aligned));
+};
-extern "C" void *
-_Jv_type_matcher (java_eh_info *info, void* match_info,
- void *exception_table)
+struct java_exception_header
{
-#ifndef SJLJ_EXCEPTIONS
- /* No exception table implies the old style mechanism, so don't check. */
- if (exception_table != NULL
- && __get_eh_table_language (exception_table) != EH_LANG_Java)
- return NULL;
-#endif
+ /* Cache handler details between Phase 1 and Phase 2. */
+ _Unwind_Ptr landingPad;
+ int handlerSwitchValue;
- /* 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 (info->value, (jclass) match_info))
- return NULL;
- }
+ /* 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)). */
+
+ char pad[sizeof(jthrowable) < sizeof(alignment_test_struct)
+ ? sizeof(alignment_test_struct) - sizeof(jthrowable) : 0]
+ __attribute__((aligned));
+
+ jthrowable value;
- return info->value;
+ /* The generic exception header. */
+ _Unwind_Exception unwindHeader;
+};
+
+// 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');
+
+
+static inline java_exception_header *
+get_exception_header_from_ue (_Unwind_Exception *exc)
+{
+ return reinterpret_cast<java_exception_header *>(exc + 1) - 1;
}
-/* 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;
+ /* FIXME: Use the proper API to the collector. */
+ java_exception_header *xh
+ = static_cast<java_exception_header *>(GC_malloc (sizeof (*xh)));
+
+ if (value == NULL)
+ value = new java::lang::NullPointerException ();
+ xh->value = value;
- if (info == NULL)
- abort ();
+ xh->unwindHeader.exception_class = __gcj_exception_class;
+ xh->unwindHeader.exception_cleanup = NULL;
- ptr = info->value;
+ /* We're happy with setjmp/longjmp exceptions or region-based
+ exception handlers: entry points are provided here for both. */
+ _Unwind_Reason_Code code;
+#ifdef SJLJ_EXCEPTIONS
+ code = _Unwind_SjLj_RaiseException (&xh->unwindHeader);
+#else
+ code = _Unwind_RaiseException (&xh->unwindHeader);
+#endif
- /* clear the value so another throw is an error */
- info->value = NULL;
+ /* FIXME: If code == _URC_END_OF_STACK, then we reached top of
+ stack without finding a handler for the exception. I seem to
+ recall that Java has specific rules to handle this.
- return ptr;
+ 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 we'll almost certainly have crashed before now, rather
+ than actually being able to diagnose the problem. */
+ abort ();
}
+
+// ??? These ought to go somewhere else dwarf2 or dwarf2eh related.
+
+// Pointer encodings.
+#define DW_EH_PE_absptr 0x00
+#define DW_EH_PE_omit 0xff
+
+#define DW_EH_PE_uleb128 0x01
+#define DW_EH_PE_udata2 0x02
+#define DW_EH_PE_udata4 0x03
+#define DW_EH_PE_udata8 0x04
+#define DW_EH_PE_sleb128 0x09
+#define DW_EH_PE_sdata2 0x0A
+#define DW_EH_PE_sdata4 0x0B
+#define DW_EH_PE_sdata8 0x0C
+#define DW_EH_PE_signed 0x08
+
+#define DW_EH_PE_pcrel 0x10
+#define DW_EH_PE_textrel 0x20
+#define DW_EH_PE_datarel 0x30
+#define DW_EH_PE_funcrel 0x40
+
+static unsigned int
+size_of_encoded_value (unsigned char encoding)
+{
+ switch (encoding & 0x07)
+ {
+ case DW_EH_PE_absptr:
+ return sizeof (void *);
+ case DW_EH_PE_udata2:
+ return 2;
+ case DW_EH_PE_udata4:
+ return 4;
+ case DW_EH_PE_udata8:
+ return 8;
+ }
+ abort ();
+}
+static const unsigned char *
+read_encoded_value (_Unwind_Context *context, unsigned char encoding,
+ const unsigned char *p, _Unwind_Ptr *val)
+{
+ union unaligned
+ {
+ void *ptr;
+ unsigned u2 __attribute__ ((mode (HI)));
+ unsigned u4 __attribute__ ((mode (SI)));
+ unsigned u8 __attribute__ ((mode (DI)));
+ signed s2 __attribute__ ((mode (HI)));
+ signed s4 __attribute__ ((mode (SI)));
+ signed s8 __attribute__ ((mode (DI)));
+ } __attribute__((__packed__));
+
+ union unaligned *u = (union unaligned *) p;
+ _Unwind_Ptr result;
+
+ switch (encoding & 0x0f)
+ {
+ case DW_EH_PE_absptr:
+ result = (_Unwind_Ptr) u->ptr;
+ p += sizeof (void *);
+ break;
+
+ case DW_EH_PE_uleb128:
+ {
+ unsigned int shift = 0;
+ unsigned char byte;
+
+ result = 0;
+ do
+ {
+ byte = *p++;
+ result |= (_Unwind_Ptr)(byte & 0x7f) << shift;
+ shift += 7;
+ }
+ while (byte & 0x80);
+ }
+ break;
+
+ case DW_EH_PE_sleb128:
+ {
+ unsigned int shift = 0;
+ unsigned char byte;
+
+ result = 0;
+ do
+ {
+ byte = *p++;
+ result |= (_Unwind_Ptr)(byte & 0x7f) << shift;
+ shift += 7;
+ }
+ while (byte & 0x80);
+
+ if (shift < 8 * sizeof(result) && (byte & 0x40) != 0)
+ result |= -(1L << shift);
+ }
+ break;
+
+ case DW_EH_PE_udata2:
+ result = u->u2;
+ p += 2;
+ break;
+ case DW_EH_PE_udata4:
+ result = u->u4;
+ p += 4;
+ break;
+ case DW_EH_PE_udata8:
+ result = u->u8;
+ p += 8;
+ break;
+
+ case DW_EH_PE_sdata2:
+ result = u->s2;
+ p += 2;
+ break;
+ case DW_EH_PE_sdata4:
+ result = u->s4;
+ p += 4;
+ break;
+ case DW_EH_PE_sdata8:
+ result = u->s8;
+ p += 8;
+ break;
+
+ default:
+ abort ();
+ }
-/* Allocate an exception info structure for java. Called the first time
- an exception is thrown. */
+ if (result != 0)
+ switch (encoding & 0xf0)
+ {
+ case DW_EH_PE_absptr:
+ break;
-extern "C" void
-_Jv_eh_alloc ()
-{
- /* 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)
- abort ();
+ case DW_EH_PE_pcrel:
+ // Define as relative to the beginning of the pointer.
+ result += (_Unwind_Ptr) u;
+ break;
+
+ case DW_EH_PE_textrel:
+ case DW_EH_PE_datarel:
+ // FIXME.
+ abort ();
- p->value = 0;
- java_eh_info ** info_ptr = __get_eh_info ();
+ case DW_EH_PE_funcrel:
+ result += _Unwind_GetRegionStart (context);
+ break;
- /* There should NOT be an exception info pointer already. */
- if (*info_ptr != NULL)
- abort ();
+ default:
+ abort ();
+ }
- *info_ptr = p;
+ *val = result;
+ return p;
}
-/* Deallocate the current exception info structure. Called at shutdown time. */
+static inline const unsigned char *
+read_uleb128 (const unsigned char *p, _Unwind_Ptr *val)
+{
+ return read_encoded_value (0, DW_EH_PE_uleb128, p, val);
+}
-extern "C" void
-_Jv_eh_free ()
+static inline const unsigned char *
+read_sleb128 (const unsigned char *p, _Unwind_Ptr *val)
{
- 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;
+ return read_encoded_value (0, DW_EH_PE_sleb128, p, val);
}
-/* Initialize an __eh_info structure with this libraries matching info. */
+
+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)
+{
+ _Unwind_Ptr tmp;
+ unsigned char lpstart_encoding;
+
+ info->Start = (context ? _Unwind_GetRegionStart (context) : 0);
-extern "C" void
-_Jv_setup_eh_info (__eh_info *)
+ // 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)
+ {
+ 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;
+
+ return p;
+}
+
+static jclass
+get_ttype_entry (_Unwind_Context *context, lsda_header_info *info, long i)
{
+ _Unwind_Ptr ptr;
+
+ i *= size_of_encoded_value (info->ttype_encoding);
+ read_encoded_value (context, info->ttype_encoding, info->TType - i, &ptr);
+
+ return reinterpret_cast<jclass>(ptr);
}
-/* Perform a throw, Java style. Throw will unwind through this call,
- so there better not be any handlers or exception thrown here. */
+// Using a different personality function name causes link failures
+// when trying to mix code using different exception handling models.
#ifdef SJLJ_EXCEPTIONS
-#define _Jv_Throw _Jv_Sjlj_Throw
+#define PERSONALITY_FUNCTION __gcj_personality_sj0
+#define __builtin_eh_return_data_regno(x) x
+#else
+#define PERSONALITY_FUNCTION __gcj_personality_v0
#endif
-extern "C" void
-_Jv_Throw (jthrowable value)
+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)
{
- if (value == NULL)
- value = new java::lang::NullPointerException;
- java_eh_info *ehinfo = *(__get_eh_info ());
- if (ehinfo == 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;
+
+
+ // Interface version check.
+ if (version != 1)
+ return _URC_FATAL_PHASE1_ERROR;
+
+ // Shortcut for phase 2 found handler for domestic exception.
+ if (actions == (_UA_CLEANUP_PHASE | _UA_HANDLER_FRAME)
+ && exception_class == __gcj_exception_class)
{
- _Jv_eh_alloc ();
- ehinfo = *(__get_eh_info ());
+ handler_switch_value = xh->handlerSwitchValue;
+ landing_pad = xh->landingPad;
+ goto install_context;
}
- 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;
-/* We're happy with setjmp/longjmp exceptions or region-based
- exception handlers: entry points are provided here for both. */
+ // FIXME: In Phase 1, record _Unwind_GetIP 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_GetIP 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)
+ return _URC_CONTINUE_UNWIND;
+
+ // Parse the LSDA header.
+ p = parse_lsda_header (context, language_specific_data, &info);
+ ip = _Unwind_GetIP (context) - 1;
+ landing_pad = 0;
+ action_record = 0;
+ handler_switch_value = 0;
+
#ifdef SJLJ_EXCEPTIONS
- __sjthrow ();
+ // 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
+ {
+ _Unwind_Ptr 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
- __throw ();
-#endif
-}
+ // 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, 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
-#ifdef USE_WIN32_SIGNALLING
+ // 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.
+ return _URC_CONTINUE_UNWIND;
-// This is a mangled version of _Jv_Throw and __sjthrow except
-// rather than calling longjmp, it returns a pointer to the jmp buffer
+ found_something:
+ saw_cleanup = false;
+ saw_handler = false;
-extern "C" int *
-win32_get_restart_frame (void *value)
-{
- struct eh_context *eh = (struct eh_context *)__get_eh_context ();
- void ***dhc = &eh->dynamic_handler_chain;
-
- java_eh_info *ehinfo = *(__get_eh_info ());
- if (ehinfo == NULL)
+ if (landing_pad == 0)
{
- _Jv_eh_alloc ();
- ehinfo = *(__get_eh_info ());
+ // 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.
+ signed long ar_filter, ar_disp;
+
+ while (1)
+ {
+ _Unwind_Ptr tmp;
+
+ p = action_record;
+ p = read_sleb128 (p, &tmp); ar_filter = tmp;
+ read_sleb128 (p, &tmp); ar_disp = tmp;
+
+ 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)
+ || exception_class != __gcj_exception_class)
+ ;
+
+ else if (ar_filter > 0)
+ {
+ // Positive filter values are handlers.
+
+ jclass catch_type = get_ttype_entry (context, &info, ar_filter);
+
+ // The catch_type is either a (java::lang::Class*) or
+ // is one more than a (Utf8Const*).
+ if ((size_t)catch_type & 1)
+ catch_type = _Jv_FindClass ((Utf8Const*)catch_type - 1, NULL);
+
+ 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;
+ }
}
- 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;
-
- // FIXME: Run clean ups?
- int *jmpbuf = (int*)&(*dhc)[2];
+ if (! saw_handler && ! saw_cleanup)
+ return _URC_CONTINUE_UNWIND;
- *dhc = (void**)(*dhc)[0];
+ if (actions & _UA_SEARCH_PHASE)
+ {
+ if (! saw_handler)
+ return _URC_CONTINUE_UNWIND;
+
+ // For domestic exceptions, we cache data from phase 1 for phase 2.
+ if (exception_class == __gcj_exception_class)
+ {
+ xh->handlerSwitchValue = handler_switch_value;
+ xh->landingPad = landing_pad;
+ }
+ return _URC_HANDLER_FOUND;
+ }
- return jmpbuf;
+ 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);
+ return _URC_INSTALL_CONTEXT;
}
-
-#endif /* USE_WIN32_SIGNALLING */