/gcc-3.2.3-20040701/gcc/java/except.c
C | 454 lines | 317 code | 57 blank | 80 comment | 62 complexity | 5b2af65686524eca449faf1afe8513ef MD5 | raw file
Possible License(s): GPL-2.0, LGPL-2.1, LGPL-2.0, CC-BY-SA-3.0
- /* Handle exceptions for GNU compiler for the Java(TM) language.
- Copyright (C) 1997, 1998, 1999, 2000, 2002 Free Software Foundation, Inc.
- This file is part of GNU CC.
- GNU CC is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2, or (at your option)
- any later version.
- GNU CC is distributed in the hope that it will be useful,
- but WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- GNU General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with GNU CC; see the file COPYING. If not, write to
- the Free Software Foundation, 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
- Java and all Java-based marks are trademarks or registered trademarks
- of Sun Microsystems, Inc. in the United States and other countries.
- The Free Software Foundation is independent of Sun Microsystems, Inc. */
- #include "config.h"
- #include "system.h"
- #include "tree.h"
- #include "real.h"
- #include "rtl.h"
- #include "java-tree.h"
- #include "javaop.h"
- #include "java-opcodes.h"
- #include "jcf.h"
- #include "function.h"
- #include "except.h"
- #include "java-except.h"
- #include "toplev.h"
- static void expand_start_java_handler PARAMS ((struct eh_range *));
- static void expand_end_java_handler PARAMS ((struct eh_range *));
- static struct eh_range *find_handler_in_range PARAMS ((int, struct eh_range *,
- struct eh_range *));
- static void link_handler PARAMS ((struct eh_range *, struct eh_range *));
- static void check_start_handlers PARAMS ((struct eh_range *, int));
- static void free_eh_ranges PARAMS ((struct eh_range *range));
- extern struct obstack permanent_obstack;
- struct eh_range *current_method_handlers;
- struct eh_range *current_try_block = NULL;
- struct eh_range *eh_range_freelist = NULL;
- /* These variables are used to speed up find_handler. */
- static int cache_range_start, cache_range_end;
- static struct eh_range *cache_range;
- static struct eh_range *cache_next_child;
- /* A dummy range that represents the entire method. */
- struct eh_range whole_range;
- #if defined(DEBUG_JAVA_BINDING_LEVELS)
- extern int binding_depth;
- extern int is_class_level;
- extern int current_pc;
- extern void indent ();
- #endif
- /* Search for the most specific eh_range containing PC.
- Assume PC is within RANGE.
- CHILD is a list of children of RANGE such that any
- previous children have end_pc values that are too low. */
- static struct eh_range *
- find_handler_in_range (pc, range, child)
- int pc;
- struct eh_range *range;
- register struct eh_range *child;
- {
- for (; child != NULL; child = child->next_sibling)
- {
- if (pc < child->start_pc)
- break;
- if (pc < child->end_pc)
- return find_handler_in_range (pc, child, child->first_child);
- }
- cache_range = range;
- cache_range_start = pc;
- cache_next_child = child;
- cache_range_end = child == NULL ? range->end_pc : child->start_pc;
- return range;
- }
- /* Find the inner-most handler that contains PC. */
- struct eh_range *
- find_handler (pc)
- int pc;
- {
- struct eh_range *h;
- if (pc >= cache_range_start)
- {
- h = cache_range;
- if (pc < cache_range_end)
- return h;
- while (pc >= h->end_pc)
- {
- cache_next_child = h->next_sibling;
- h = h->outer;
- }
- }
- else
- {
- h = &whole_range;
- cache_next_child = h->first_child;
- }
- return find_handler_in_range (pc, h, cache_next_child);
- }
- /* Recursive helper routine for check_nested_ranges. */
- static void
- link_handler (range, outer)
- struct eh_range *range, *outer;
- {
- struct eh_range **ptr;
- if (range->start_pc == outer->start_pc && range->end_pc == outer->end_pc)
- {
- outer->handlers = chainon (outer->handlers, range->handlers);
- return;
- }
- /* If the new range completely encloses the `outer' range, then insert it
- between the outer range and its parent. */
- if (range->start_pc <= outer->start_pc && range->end_pc >= outer->end_pc)
- {
- range->outer = outer->outer;
- range->next_sibling = NULL;
- range->first_child = outer;
- {
- struct eh_range **pr = &(outer->outer->first_child);
- while (*pr != outer)
- pr = &(*pr)->next_sibling;
- *pr = range;
- }
- outer->outer = range;
- return;
- }
- /* Handle overlapping ranges by splitting the new range. */
- if (range->start_pc < outer->start_pc || range->end_pc > outer->end_pc)
- {
- struct eh_range *h
- = (struct eh_range *) xmalloc (sizeof (struct eh_range));
- if (range->start_pc < outer->start_pc)
- {
- h->start_pc = range->start_pc;
- h->end_pc = outer->start_pc;
- range->start_pc = outer->start_pc;
- }
- else
- {
- h->start_pc = outer->end_pc;
- h->end_pc = range->end_pc;
- range->end_pc = outer->end_pc;
- }
- h->first_child = NULL;
- h->outer = NULL;
- h->handlers = build_tree_list (TREE_PURPOSE (range->handlers),
- TREE_VALUE (range->handlers));
- h->next_sibling = NULL;
- h->expanded = 0;
- /* Restart both from the top to avoid having to make this
- function smart about reentrancy. */
- link_handler (h, &whole_range);
- link_handler (range, &whole_range);
- return;
- }
- ptr = &outer->first_child;
- for (;; ptr = &(*ptr)->next_sibling)
- {
- if (*ptr == NULL || range->end_pc <= (*ptr)->start_pc)
- {
- range->next_sibling = *ptr;
- range->first_child = NULL;
- range->outer = outer;
- *ptr = range;
- return;
- }
- else if (range->start_pc < (*ptr)->end_pc)
- {
- link_handler (range, *ptr);
- return;
- }
- /* end_pc > (*ptr)->start_pc && start_pc >= (*ptr)->end_pc. */
- }
- }
- /* The first pass of exception range processing (calling add_handler)
- constructs a linked list of exception ranges. We turn this into
- the data structure expected by the rest of the code, and also
- ensure that exception ranges are properly nested. */
- void
- handle_nested_ranges ()
- {
- struct eh_range *ptr, *next;
- ptr = whole_range.first_child;
- whole_range.first_child = NULL;
- for (; ptr; ptr = next)
- {
- next = ptr->next_sibling;
- ptr->next_sibling = NULL;
- link_handler (ptr, &whole_range);
- }
- }
- /* Free RANGE as well as its children and siblings. */
- static void
- free_eh_ranges (range)
- struct eh_range *range;
- {
- while (range)
- {
- struct eh_range *next = range->next_sibling;
- free_eh_ranges (range->first_child);
- if (range != &whole_range)
- free (range);
- range = next;
- }
- }
- /* Called to re-initialize the exception machinery for a new method. */
- void
- method_init_exceptions ()
- {
- free_eh_ranges (&whole_range);
- whole_range.start_pc = 0;
- whole_range.end_pc = DECL_CODE_LENGTH (current_function_decl) + 1;
- whole_range.outer = NULL;
- whole_range.first_child = NULL;
- whole_range.next_sibling = NULL;
- cache_range_start = 0xFFFFFF;
- }
- /* Add an exception range. If we already have an exception range
- which has the same handler and label, and the new range overlaps
- that one, then we simply extend the existing range. Some bytecode
- obfuscators generate seemingly nonoverlapping exception ranges
- which, when coalesced, do in fact nest correctly.
-
- This constructs an ordinary linked list which check_nested_ranges()
- later turns into the data structure we actually want.
-
- We expect the input to come in order of increasing START_PC. This
- function doesn't attempt to detect the case where two previously
- added disjoint ranges could be coalesced by a new range; that is
- what the sorting counteracts. */
- void
- add_handler (start_pc, end_pc, handler, type)
- int start_pc, end_pc;
- tree handler;
- tree type;
- {
- struct eh_range *ptr, *prev = NULL, *h;
- for (ptr = whole_range.first_child; ptr; ptr = ptr->next_sibling)
- {
- if (start_pc >= ptr->start_pc
- && start_pc <= ptr->end_pc
- && TREE_PURPOSE (ptr->handlers) == type
- && TREE_VALUE (ptr->handlers) == handler)
- {
- /* Already found an overlapping range, so coalesce. */
- ptr->end_pc = MAX (ptr->end_pc, end_pc);
- return;
- }
- prev = ptr;
- }
- h = (struct eh_range *) xmalloc (sizeof (struct eh_range));
- h->start_pc = start_pc;
- h->end_pc = end_pc;
- h->first_child = NULL;
- h->outer = NULL;
- h->handlers = build_tree_list (type, handler);
- h->next_sibling = NULL;
- h->expanded = 0;
- if (prev == NULL)
- whole_range.first_child = h;
- else
- prev->next_sibling = h;
- }
- /* if there are any handlers for this range, issue start of region */
- static void
- expand_start_java_handler (range)
- struct eh_range *range;
- {
- #if defined(DEBUG_JAVA_BINDING_LEVELS)
- indent ();
- fprintf (stderr, "expand start handler pc %d --> %d\n",
- current_pc, range->end_pc);
- #endif /* defined(DEBUG_JAVA_BINDING_LEVELS) */
- range->expanded = 1;
- expand_eh_region_start ();
- }
- tree
- prepare_eh_table_type (type)
- tree type;
- {
- tree exp;
- /* The "type" (metch_info) in a (Java) exception table is one:
- * a) NULL - meaning match any type in a try-finally.
- * b) a pointer to a (ccmpiled) class (low-order bit 0).
- * c) a pointer to the Utf8Const name of the class, plus one
- * (which yields a value with low-order bit 1). */
- if (type == NULL_TREE)
- exp = NULL_TREE;
- else if (is_compiled_class (type))
- exp = build_class_ref (type);
- else
- exp = fold (build
- (PLUS_EXPR, ptr_type_node,
- build_utf8_ref (build_internal_class_name (type)),
- size_one_node));
- return exp;
- }
- /* Build a reference to the jthrowable object being carried in the
- exception header. */
- tree
- build_exception_object_ref (type)
- tree type;
- {
- tree obj;
- /* Java only passes object via pointer and doesn't require adjusting.
- The java object is immediately before the generic exception header. */
- obj = build (EXC_PTR_EXPR, build_pointer_type (type));
- obj = build (MINUS_EXPR, TREE_TYPE (obj), obj,
- TYPE_SIZE_UNIT (TREE_TYPE (obj)));
- obj = build1 (INDIRECT_REF, type, obj);
- return obj;
- }
- /* If there are any handlers for this range, isssue end of range,
- and then all handler blocks */
- static void
- expand_end_java_handler (range)
- struct eh_range *range;
- {
- tree handler = range->handlers;
- force_poplevels (range->start_pc);
- expand_start_all_catch ();
- for ( ; handler != NULL_TREE; handler = TREE_CHAIN (handler))
- {
- /* For bytecode we treat exceptions a little unusually. A
- `finally' clause looks like an ordinary exception handler for
- Throwable. The reason for this is that the bytecode has
- already expanded the finally logic, and we would have to do
- extra (and difficult) work to get this to look like a
- gcc-style finally clause. */
- tree type = TREE_PURPOSE (handler);
- if (type == NULL)
- type = throwable_type_node;
- expand_start_catch (type);
- expand_goto (TREE_VALUE (handler));
- expand_end_catch ();
- }
- expand_end_all_catch ();
- #if defined(DEBUG_JAVA_BINDING_LEVELS)
- indent ();
- fprintf (stderr, "expand end handler pc %d <-- %d\n",
- current_pc, range->start_pc);
- #endif /* defined(DEBUG_JAVA_BINDING_LEVELS) */
- }
- /* Recursive helper routine for maybe_start_handlers. */
- static void
- check_start_handlers (range, pc)
- struct eh_range *range;
- int pc;
- {
- if (range != NULL_EH_RANGE && range->start_pc == pc)
- {
- check_start_handlers (range->outer, pc);
- if (!range->expanded)
- expand_start_java_handler (range);
- }
- }
- static struct eh_range *current_range;
- /* Emit any start-of-try-range starting at start_pc and ending after
- end_pc. */
- void
- maybe_start_try (start_pc, end_pc)
- int start_pc;
- int end_pc;
- {
- struct eh_range *range;
- if (! doing_eh (1))
- return;
- range = find_handler (start_pc);
- while (range != NULL_EH_RANGE && range->start_pc == start_pc
- && range->end_pc < end_pc)
- range = range->outer;
-
- current_range = range;
- check_start_handlers (range, start_pc);
- }
- /* Emit any end-of-try-range ending at end_pc and starting before
- start_pc. */
- void
- maybe_end_try (start_pc, end_pc)
- int start_pc;
- int end_pc;
- {
- if (! doing_eh (1))
- return;
- while (current_range != NULL_EH_RANGE && current_range->end_pc <= end_pc
- && current_range->start_pc >= start_pc)
- {
- expand_end_java_handler (current_range);
- current_range = current_range->outer;
- }
- }