/* Exception Handling interface routines.
Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
- 2007, 2008 Free Software Foundation, Inc.
+ 2007, 2008, 2009, 2010 Free Software Foundation, Inc.
Contributed by Mike Stump <mrs@cygnus.com>.
This file is part of GCC.
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
-#include "sbitmap.h"
+/* No include guards here, but define an include file marker anyway, so
+ that the compiler can keep track of where this file is included. This
+ is e.g. used to avoid including this file in front-end specific files. */
+#ifndef GCC_EXCEPT_H
+# define GCC_EXCEPT_H
+#endif
+
+#include "hashtab.h"
#include "vecprim.h"
+#include "vecir.h"
struct function;
+struct eh_region_d;
+struct pointer_map_t;
-/* Per-function EH data. Used only in except.c, but GC and others
- manipulate pointers to the opaque type. */
-struct eh_status;
+/* The type of an exception region. */
+enum eh_region_type
+{
+ /* CLEANUP regions implement e.g. destructors run when exiting a block.
+ They can be generated from both GIMPLE_TRY_FINALLY and GIMPLE_TRY_CATCH
+ nodes. It is expected by the runtime that cleanup regions will *not*
+ resume normal program flow, but will continue propagation of the
+ exception. */
+ ERT_CLEANUP,
+
+ /* TRY regions implement catching an exception. The list of types associated
+ with the attached catch handlers is examined in order by the runtime and
+ control is transfered to the appropriate handler. Note that a NULL type
+ list is a catch-all handler, and that it will catch *all* exceptions
+ including those originating from a different language. */
+ ERT_TRY,
+
+ /* ALLOWED_EXCEPTIONS regions implement exception filtering, e.g. the
+ throw(type-list) specification that can be added to C++ functions.
+ The runtime examines the thrown exception vs the type list, and if
+ the exception does not match, transfers control to the handler. The
+ normal handler for C++ calls __cxa_call_unexpected. */
+ ERT_ALLOWED_EXCEPTIONS,
+
+ /* MUST_NOT_THROW regions prevent all exceptions from propagating. This
+ region type is used in C++ to surround destructors being run inside a
+ CLEANUP region. This differs from an ALLOWED_EXCEPTIONS region with
+ an empty type list in that the runtime is prepared to terminate the
+ program directly. We only generate code for MUST_NOT_THROW regions
+ along control paths that are already handling an exception within the
+ current function. */
+ ERT_MUST_NOT_THROW
+};
-/* Internal structure describing a region. */
-struct eh_region;
-/* Test: is exception handling turned on? */
-extern int doing_eh (int);
+/* A landing pad for a given exception region. Any transfer of control
+ from the EH runtime to the function happens at a landing pad. */
-/* Note that the current EH region (if any) may contain a throw, or a
- call to a function which itself may contain a throw. */
-extern void note_eh_region_may_contain_throw (struct eh_region *);
+struct GTY(()) eh_landing_pad_d
+{
+ /* The linked list of all landing pads associated with the region. */
+ struct eh_landing_pad_d *next_lp;
+
+ /* The region with which this landing pad is associated. */
+ struct eh_region_d *region;
+
+ /* At the gimple level, the location to which control will be transfered
+ for this landing pad. There can be both EH and normal edges into the
+ block containing the post-landing-pad label. */
+ tree post_landing_pad;
+
+ /* At the rtl level, the location to which the runtime will transfer
+ control. This differs from the post-landing-pad in that the target's
+ EXCEPTION_RECEIVER pattern will be expanded here, as well as other
+ bookkeeping specific to exceptions. There must not be normal edges
+ into the block containing the landing-pad label. */
+ rtx landing_pad;
+
+ /* The index of this landing pad within fun->eh->lp_array. */
+ int index;
+};
-/* Invokes CALLBACK for every exception handler label. Only used by old
- loop hackery; should not be used by new code. */
-extern void for_each_eh_label (void (*) (rtx));
+/* A catch handler associated with an ERT_TRY region. */
-/* Invokes CALLBACK for every exception region in the current function. */
-extern void for_each_eh_region (void (*) (struct eh_region *));
+struct GTY(()) eh_catch_d
+{
+ /* The double-linked list of all catch handlers for the region. */
+ struct eh_catch_d *next_catch;
+ struct eh_catch_d *prev_catch;
+
+ /* A TREE_LIST of runtime type objects that this catch handler
+ will catch, or NULL if all exceptions are caught. */
+ tree type_list;
+
+ /* A TREE_LIST of INTEGER_CSTs that correspond to the type_list entries,
+ having been mapped by assign_filter_values. These integers are to be
+ compared against the __builtin_eh_filter value. */
+ tree filter_list;
+
+ /* The code that should be executed if this catch handler matches the
+ thrown exception. This label is only maintained until
+ pass_lower_eh_dispatch, at which point it is cleared. */
+ tree label;
+};
-/* Determine if the given INSN can throw an exception. */
-extern bool can_throw_internal_1 (int, bool, bool);
-extern bool can_throw_internal (const_rtx);
-extern bool can_throw_external_1 (int, bool, bool);
-extern bool can_throw_external (const_rtx);
+/* Describes one exception region. */
-/* Set TREE_NOTHROW and cfun->all_throwers_are_sibcalls. */
-extern unsigned int set_nothrow_function_flags (void);
+struct GTY(()) eh_region_d
+{
+ /* The immediately surrounding region. */
+ struct eh_region_d *outer;
+
+ /* The list of immediately contained regions. */
+ struct eh_region_d *inner;
+ struct eh_region_d *next_peer;
+
+ /* The index of this region within fun->eh->region_array. */
+ int index;
+
+ /* Each region does exactly one thing. */
+ enum eh_region_type type;
+
+ /* Holds the action to perform based on the preceding type. */
+ union eh_region_u {
+ struct eh_region_u_try {
+ /* The double-linked list of all catch handlers for this region. */
+ struct eh_catch_d *first_catch;
+ struct eh_catch_d *last_catch;
+ } GTY ((tag ("ERT_TRY"))) eh_try;
+
+ struct eh_region_u_allowed {
+ /* A TREE_LIST of runtime type objects allowed to pass. */
+ tree type_list;
+ /* The code that should be executed if the thrown exception does
+ not match the type list. This label is only maintained until
+ pass_lower_eh_dispatch, at which point it is cleared. */
+ tree label;
+ /* The integer that will be passed by the runtime to signal that
+ we should execute the code at LABEL. This integer is assigned
+ by assign_filter_values and is to be compared against the
+ __builtin_eh_filter value. */
+ int filter;
+ } GTY ((tag ("ERT_ALLOWED_EXCEPTIONS"))) allowed;
+
+ struct eh_region_u_must_not_throw {
+ /* A function decl to be invoked if this region is actually reachable
+ from within the function, rather than implementable from the runtime.
+ The normal way for this to happen is for there to be a CLEANUP region
+ contained within this MUST_NOT_THROW region. Note that if the
+ runtime handles the MUST_NOT_THROW region, we have no control over
+ what termination function is called; it will be decided by the
+ personality function in effect for this CIE. */
+ tree failure_decl;
+ /* The location assigned to the call of FAILURE_DECL, if expanded. */
+ location_t failure_loc;
+ } GTY ((tag ("ERT_MUST_NOT_THROW"))) must_not_throw;
+ } GTY ((desc ("%0.type"))) u;
+
+ /* The list of landing pads associated with this region. */
+ struct eh_landing_pad_d *landing_pads;
+
+ /* EXC_PTR and FILTER values copied from the runtime for this region.
+ Each region gets its own psuedos so that if there are nested exceptions
+ we do not overwrite the values of the first exception. */
+ rtx exc_ptr_reg, filter_reg;
+
+ /* True if this region should use __cxa_end_cleanup instead
+ of _Unwind_Resume. */
+ bool use_cxa_end_cleanup;
+};
+
+typedef struct eh_landing_pad_d *eh_landing_pad;
+typedef struct eh_catch_d *eh_catch;
+typedef struct eh_region_d *eh_region;
+
+DEF_VEC_P(eh_region);
+DEF_VEC_ALLOC_P(eh_region, gc);
+DEF_VEC_ALLOC_P(eh_region, heap);
+
+DEF_VEC_P(eh_landing_pad);
+DEF_VEC_ALLOC_P(eh_landing_pad, gc);
+
+
+/* The exception status for each function. */
+
+struct GTY(()) eh_status
+{
+ /* The tree of all regions for this function. */
+ eh_region region_tree;
+
+ /* The same information as an indexable array. */
+ VEC(eh_region,gc) *region_array;
+
+ /* The landing pads as an indexable array. */
+ VEC(eh_landing_pad,gc) *lp_array;
+
+ /* At the gimple level, a mapping from gimple statement to landing pad
+ or must-not-throw region. See record_stmt_eh_region. */
+ htab_t GTY((param_is (struct throw_stmt_node))) throw_stmt_table;
+
+ /* All of the runtime type data used by the function. These objects
+ are emitted to the lang-specific-data-area for the function. */
+ VEC(tree,gc) *ttype_data;
+
+ /* The table of all action chains. These encode the eh_region tree in
+ a compact form for use by the runtime, and is also emitted to the
+ lang-specific-data-area. Note that the ARM EABI uses a different
+ format for the encoding than all other ports. */
+ union eh_status_u {
+ VEC(tree,gc) * GTY((tag ("1"))) arm_eabi;
+ VEC(uchar,gc) * GTY((tag ("0"))) other;
+ } GTY ((desc ("targetm.arm_eabi_unwinder"))) ehspec_data;
+};
-/* After initial rtl generation, call back to finish generating
- exception support code. */
-extern void finish_eh_generation (void);
-extern void init_eh (void);
+/* Invokes CALLBACK for every exception handler label. Only used by old
+ loop hackery; should not be used by new code. */
+extern void for_each_eh_label (void (*) (rtx));
+
extern void init_eh_for_function (void);
-extern rtx reachable_handlers (rtx);
-void remove_eh_region (int);
+extern void remove_eh_landing_pad (eh_landing_pad);
+extern void remove_eh_handler (eh_region);
-extern void convert_from_eh_region_ranges (void);
-extern unsigned int convert_to_eh_region_ranges (void);
-extern void find_exception_handler_labels (void);
extern bool current_function_has_exception_handlers (void);
extern void output_function_exception_table (const char *);
+extern rtx expand_builtin_eh_pointer (tree);
+extern rtx expand_builtin_eh_filter (tree);
+extern rtx expand_builtin_eh_copy_values (tree);
extern void expand_builtin_unwind_init (void);
extern rtx expand_builtin_eh_return_data_regno (tree);
extern rtx expand_builtin_extract_return_addr (tree);
extern void expand_builtin_eh_return (tree, tree);
extern void expand_eh_return (void);
extern rtx expand_builtin_extend_pointer (tree);
-extern rtx get_exception_pointer (void);
-extern rtx get_exception_filter (void);
+extern void expand_dw2_landing_pad_for_region (eh_region);
+
typedef tree (*duplicate_eh_regions_map) (tree, void *);
-extern int duplicate_eh_regions (struct function *, duplicate_eh_regions_map,
- void *, int, int);
+extern struct pointer_map_t *duplicate_eh_regions
+ (struct function *, eh_region, int, duplicate_eh_regions_map, void *);
extern void sjlj_emit_function_exit_after (rtx);
-extern void default_init_unwind_resume_libfunc (void);
-
-extern struct eh_region *gen_eh_region_cleanup (struct eh_region *,
- struct eh_region *);
-extern struct eh_region *gen_eh_region_try (struct eh_region *);
-extern struct eh_region *gen_eh_region_catch (struct eh_region *, tree);
-extern struct eh_region *gen_eh_region_allowed (struct eh_region *, tree);
-extern struct eh_region *gen_eh_region_must_not_throw (struct eh_region *);
-extern int get_eh_region_number (struct eh_region *);
-extern bool get_eh_region_may_contain_throw (struct eh_region *);
-extern tree get_eh_region_no_tree_label (int);
-extern tree get_eh_region_tree_label (struct eh_region *);
-extern void set_eh_region_tree_label (struct eh_region *, tree);
-
-extern void foreach_reachable_handler (int, bool, bool,
- void (*) (struct eh_region *, void *),
- void *);
-
-extern void collect_eh_region_array (void);
-extern void expand_resx_expr (tree);
+
+extern eh_region gen_eh_region_cleanup (eh_region);
+extern eh_region gen_eh_region_try (eh_region);
+extern eh_region gen_eh_region_allowed (eh_region, tree);
+extern eh_region gen_eh_region_must_not_throw (eh_region);
+
+extern eh_catch gen_eh_region_catch (eh_region, tree);
+extern eh_landing_pad gen_eh_landing_pad (eh_region);
+
+extern eh_region get_eh_region_from_number_fn (struct function *, int);
+extern eh_region get_eh_region_from_number (int);
+extern eh_landing_pad get_eh_landing_pad_from_number_fn (struct function*,int);
+extern eh_landing_pad get_eh_landing_pad_from_number (int);
+extern eh_region get_eh_region_from_lp_number_fn (struct function *, int);
+extern eh_region get_eh_region_from_lp_number (int);
+
+extern eh_region eh_region_outermost (struct function *, eh_region, eh_region);
+
+extern void make_reg_eh_region_note (rtx insn, int ecf_flags, int lp_nr);
+extern void make_reg_eh_region_note_nothrow_nononlocal (rtx);
+
extern void verify_eh_tree (struct function *);
extern void dump_eh_tree (FILE *, struct function *);
-extern int eh_region_outermost (struct function *, int, int);
-
-/* If non-NULL, this is a function that returns an expression to be
- executed if an unhandled exception is propagated out of a cleanup
- region. For example, in C++, an exception thrown by a destructor
- during stack unwinding is required to result in a call to
- `std::terminate', so the C++ version of this function returns a
- CALL_EXPR for `std::terminate'. */
-extern gimple (*lang_protect_cleanup_actions) (void);
-
-/* Return true if type A catches type B. */
-extern int (*lang_eh_type_covers) (tree a, tree b);
-
-/* Map a type to a runtime object to match type. */
-extern tree (*lang_eh_runtime_type) (tree);
-
-
-/* Just because the user configured --with-sjlj-exceptions=no doesn't
- mean that we can use call frame exceptions. Detect that the target
- has appropriate support. */
-
-#ifndef MUST_USE_SJLJ_EXCEPTIONS
-# if defined (EH_RETURN_DATA_REGNO) \
- && (defined (TARGET_UNWIND_INFO) \
- || (DWARF2_UNWIND_INFO \
- && (defined (EH_RETURN_HANDLER_RTX) \
- || defined (HAVE_eh_return))))
-# define MUST_USE_SJLJ_EXCEPTIONS 0
-# else
-# define MUST_USE_SJLJ_EXCEPTIONS 1
-# endif
-#endif
+void debug_eh_tree (struct function *);
+extern void add_type_for_runtime (tree);
+extern tree lookup_type_for_runtime (tree);
+extern void assign_filter_values (void);
-#ifdef CONFIG_SJLJ_EXCEPTIONS
-# if CONFIG_SJLJ_EXCEPTIONS == 1
-# define USING_SJLJ_EXCEPTIONS 1
-# endif
-# if CONFIG_SJLJ_EXCEPTIONS == 0
-# define USING_SJLJ_EXCEPTIONS 0
-# if !defined(EH_RETURN_DATA_REGNO)
- #error "EH_RETURN_DATA_REGNO required"
-# endif
-# if ! (defined(TARGET_UNWIND_INFO) || DWARF2_UNWIND_INFO)
- #error "{DWARF2,TARGET}_UNWIND_INFO required"
-# endif
-# if !defined(TARGET_UNWIND_INFO) \
- && !(defined(EH_RETURN_HANDLER_RTX) || defined(HAVE_eh_return))
- #error "EH_RETURN_HANDLER_RTX or eh_return required"
-# endif
-/* Usually the above error checks will have already triggered an
- error, but backends may set MUST_USE_SJLJ_EXCEPTIONS for their own
- reasons. */
-# if MUST_USE_SJLJ_EXCEPTIONS
- #error "Must use SJLJ exceptions but configured not to"
-# endif
-# endif
-#else
-# define USING_SJLJ_EXCEPTIONS MUST_USE_SJLJ_EXCEPTIONS
-#endif
+extern eh_region get_eh_region_from_rtx (const_rtx);
+extern eh_landing_pad get_eh_landing_pad_from_rtx (const_rtx);
-struct throw_stmt_node GTY(())
-{
+struct GTY(()) throw_stmt_node {
gimple stmt;
- int region_nr;
+ int lp_nr;
};
extern struct htab *get_eh_throw_stmt_table (struct function *);
extern void set_eh_throw_stmt_table (struct function *, struct htab *);
-extern void remove_unreachable_regions (sbitmap, sbitmap);
-extern VEC(int,heap) * label_to_region_map (void);
-extern int num_eh_regions (void);
+
+enum eh_personality_kind {
+ eh_personality_none,
+ eh_personality_any,
+ eh_personality_lang
+};
+
+extern enum eh_personality_kind
+function_needs_eh_personality (struct function *);
+
+/* Pre-order iteration within the eh_region tree. */
+
+static inline eh_region
+ehr_next (eh_region r, eh_region start)
+{
+ if (r->inner)
+ r = r->inner;
+ else if (r->next_peer && r != start)
+ r = r->next_peer;
+ else
+ {
+ do
+ {
+ r = r->outer;
+ if (r == start)
+ return NULL;
+ }
+ while (r->next_peer == NULL);
+ r = r->next_peer;
+ }
+ return r;
+}
+
+#define FOR_ALL_EH_REGION_AT(R, START) \
+ for ((R) = (START); (R) != NULL; (R) = ehr_next (R, START))
+
+#define FOR_ALL_EH_REGION_FN(R, FN) \
+ for ((R) = (FN)->eh->region_tree; (R) != NULL; (R) = ehr_next (R, NULL))
+
+#define FOR_ALL_EH_REGION(R) FOR_ALL_EH_REGION_FN (R, cfun)