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Update documentation.

From-SVN: r12715
This commit is contained in:
Richard Kenner 1996-09-14 20:44:58 -04:00
parent ef19912d09
commit 911fdd58bb
1 changed files with 152 additions and 15 deletions
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167
gcc/except.h
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@ -26,6 +26,8 @@ Boston, MA 02111-1307, USA. */
#ifdef TREE_CODE
/* A stack of labels. CHAIN points to the next entry in the stack. */
struct label_node {
union {
rtx rlabel;
@ -34,8 +36,19 @@ struct label_node {
struct label_node *chain;
};
/* A entry for the exception handling stack EHSTACK or the exception
handling queue EHQUEUE. */
/* An eh_entry is used to describe one exception handling region.
START_LABEL is the label corresponding to the start of the region.
END_LABEL is the label corresponding to the end of the region.
EXCEPTION_HANDLER_LABEL is the label corresponding to the handler
for this region.
FINALIZATION is the tree codes for the handler, or is NULL_TREE if
one hasn't been generated yet, or is integer_zero_node to mark the
end of a group of try blocks. */
struct eh_entry {
rtx start_label;
rtx end_label;
@ -44,55 +57,179 @@ struct eh_entry {
tree finalization;
};
/* A list of EH_ENTRYs. ENTRY is the entry; CHAIN points to the next
entry in the list, or is NULL if this is the last entry. */
struct eh_node {
struct eh_entry *entry;
struct eh_node *chain;
};
/* A stack of EH_ENTRYs. TOP is the topmost entry on the stack. TOP is
NULL if the stack is empty. */
struct eh_stack {
struct eh_node *top;
};
/* A queue of EH_ENTRYs. HEAD is the front of the queue; TAIL is the
end (the latest entry). HEAD and TAIL are NULL if the queue is
empty. */
struct eh_queue {
struct eh_node *head;
struct eh_node *tail;
};
extern void expand_eh_region_start PROTO((void));
extern void expand_eh_region_end PROTO((tree));
/* Push RLABEL or TLABEL onto LABELSTACK. Only one of RLABEL or TLABEL
should be set; the other must be NULL. */
extern void push_label_entry PROTO((struct label_node **labelstack, rtx rlabel, tree tlabel));
/* Pop the topmost entry from LABELSTACK and return its value as an
rtx node. If LABELSTACK is empty, return NULL. */
extern rtx pop_label_entry PROTO((struct label_node **labelstack));
/* Return the topmost entry of LABELSTACK as a tree node, or return
NULL_TREE if LABELSTACK is empty. */
extern tree top_label_entry PROTO((struct label_node **labelstack));
/* The stack used to keep track of the exception region corresponding to
the current instruction. */
extern struct eh_stack ehstack;
/* A queue used to track closed exception regions whose handlers have
not been emitted yet. */
extern struct eh_queue ehqueue;
/* A set of insns for the catch clauses in the current function. They
will be emitted at the end of the current function. */
extern rtx catch_clauses;
extern tree protect_list;
#endif
struct function;
extern void init_eh PROTO((void));
extern void init_eh_for_function PROTO((void));
extern void save_eh_status PROTO((struct function *p));
extern void restore_eh_status PROTO((struct function *p));
extern void add_eh_table_entry PROTO((int));
extern int exception_table_p PROTO((void));
extern void output_exception_table PROTO((void));
extern rtx eh_outer_context PROTO((rtx));
extern void emit_unwinder PROTO((void));
extern void end_eh_unwinder PROTO((void));
extern void find_handler_labels PROTO((void));
extern void check_handler_labels PROTO((void));
/* Toplevel initialization for EH. */
extern void init_eh PROTO((void));
/* Initialization for the per-function EH data. */
extern void init_eh_for_function PROTO((void));
/* Saves the current per-function EH data into P. */
extern void save_eh_status PROTO((struct function *p));
/* Restores the per-function EH data from P. */
extern void restore_eh_status PROTO((struct function *p));
/* Adds an EH table entry for EH entry number N. Called from
final_scan_insn for NOTE_INSN_EH_REGION_BEG. */
extern void add_eh_table_entry PROTO((int n));
/* Returns a non-zero value if we need to output an exception table. */
extern int exception_table_p PROTO((void));
/* Outputs the exception table if we have one. */
extern void output_exception_table PROTO((void));
/* Given a return address in ADDR, determine the address we should use
to find the corresponding EH region. */
extern rtx eh_outer_context PROTO((rtx addr));
/* Called at the start of a block of try statements for which there is
a supplied catch handler. */
extern void expand_start_try_stmts PROTO((void));
/* Called at the start of a block of catch statements. It terminates the
previous set of try statements. */
extern void expand_start_all_catch PROTO((void));
/* Called at the end of a block of catch statements. */
extern void expand_end_all_catch PROTO((void));
#ifdef TREE_CODE
/* Create a new exception region and add the handler for the region
onto a list. These regions will be ended (and their handlers
emitted) when end_protect_partials is invoked. */
extern void add_partial_entry PROTO((tree handler));
#endif
/* End all of the pending exception regions that have handlers added with
push_protect_entry (). */
extern void end_protect_partials PROTO((void));
/* An internal throw with a direct CONTEXT we want to throw
from. CONTEXT must be a label. */
extern void expand_internal_throw PROTO((rtx context));
/* Called from expand_exception_blocks and expand_end_catch_block to
expand and pending handlers. */
extern void expand_leftover_cleanups PROTO((void));
/* If necessary, emit insns for the start of per-function unwinder for
the current function. */
extern void emit_unwinder PROTO((void));
/* If necessary, emit insns for the end of the per-function unwinder
for the current function. */
extern void end_eh_unwinder PROTO((void));
/* Builds a list of handler labels and puts them in the global
variable exception_handler_labels. */
extern void find_exception_handler_labels PROTO((void));
/* Performs sanity checking on the check_exception_handler_labels
list. */
extern void check_exception_handler_labels PROTO((void));
/* A stack used to keep track of the label used to resume normal program
flow out of the current exception handler region. */
extern struct label_node *caught_return_label_stack;
/* A random area used for purposes elsewhere. */
extern struct label_node *false_label_stack;
/* A list of labels used for exception handlers. It is created by
find_exception_handler_labels for the optimization passes. */
extern rtx exception_handler_labels;
/* The rtx for the saved PC value. */
extern rtx eh_saved_pc_rtx;
/* Performs optimizations for exception handling, such as removing
unnecessary exception regions. Invoked from jump_optimize (). */
extern void exception_optimize PROTO((void));