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src/share/vm/code/exceptionHandlerTable.hpp@e9ff18c4ace7 (annotated)

src/share/vm/code/exceptionHandlerTable.hpp

Wed, 02 Jun 2010 22:45:42 -0700

author

jrose

date

Wed, 02 Jun 2010 22:45:42 -0700

changeset 1934

e9ff18c4ace7

parent 1907

c18cbe5936b8

child 2314

f95d63e2154a

permissions

-rw-r--r--

Merge

duke@435	1	/*
trims@1907	2	* Copyright (c) 1998, 2005, Oracle and/or its affiliates. All rights reserved.
duke@435	3	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@435	4	*
duke@435	5	* This code is free software; you can redistribute it and/or modify it
duke@435	6	* under the terms of the GNU General Public License version 2 only, as
duke@435	7	* published by the Free Software Foundation.
duke@435	8	*
duke@435	9	* This code is distributed in the hope that it will be useful, but WITHOUT
duke@435	10	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@435	11	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@435	12	* version 2 for more details (a copy is included in the LICENSE file that
duke@435	13	* accompanied this code).
duke@435	14	*
duke@435	15	* You should have received a copy of the GNU General Public License version
duke@435	16	* 2 along with this work; if not, write to the Free Software Foundation,
duke@435	17	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@435	18	*
trims@1907	19	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907	20	* or visit www.oracle.com if you need additional information or have any
trims@1907	21	* questions.
duke@435	22	*
duke@435	23	*/
duke@435	24
duke@435	25	// A HandlerTableEntry describes an individual entry of a subtable
duke@435	26	// of ExceptionHandlerTable. An entry consists of a pair(bci, pco),
duke@435	27	// where bci is the exception handler bci, and pco is the pc offset
duke@435	28	// relative to the nmethod code start for the compiled exception
duke@435	29	// handler corresponding to the (interpreted) exception handler
duke@435	30	// starting at bci.
duke@435	31	//
duke@435	32	// The first HandlerTableEntry of each subtable holds the length
duke@435	33	// and catch_pco for the subtable (the length is the number of
duke@435	34	// subtable entries w/o header).
duke@435	35
duke@435	36	class HandlerTableEntry {
duke@435	37	private:
duke@435	38	int _bci;
duke@435	39	int _pco;
duke@435	40	int _scope_depth;
duke@435	41
duke@435	42	public:
duke@435	43	HandlerTableEntry(int bci, int pco, int scope_depth) {
duke@435	44	assert( 0 <= pco, "pco must be positive");
duke@435	45	assert( 0 <= scope_depth, "scope_depth must be positive");
duke@435	46	_bci = bci;
duke@435	47	_pco = pco;
duke@435	48	_scope_depth = scope_depth;
duke@435	49	}
duke@435	50
duke@435	51	int len() const { return _bci; } // for entry at subtable begin
duke@435	52	int bci() const { return _bci; }
duke@435	53	int pco() const { return _pco; }
duke@435	54	int scope_depth() const { return _scope_depth; }
duke@435	55	};
duke@435	56
duke@435	57
duke@435	58	// An ExceptionHandlerTable is an abstraction over a list of subtables
duke@435	59	// of exception handlers for CatchNodes. Each subtable has a one-entry
duke@435	60	// header holding length and catch_pco of the subtable, followed
duke@435	61	// by 'length' entries for each exception handler that can be reached
duke@435	62	// from the corresponding CatchNode. The catch_pco is the pc offset of
duke@435	63	// the CatchNode in the corresponding nmethod. Empty subtables are dis-
duke@435	64	// carded.
duke@435	65	//
duke@435	66	// Structure of the table:
duke@435	67	//
duke@435	68	// table = { subtable }.
duke@435	69	// subtable = header entry { entry }.
duke@435	70	// header = a pair (number of subtable entries, catch pc offset, [unused])
duke@435	71	// entry = a pair (handler bci, handler pc offset, scope depth)
duke@435	72	//
duke@435	73	// An ExceptionHandlerTable can be created from scratch, in which case
duke@435	74	// it is possible to add subtables. It can also be created from an
duke@435	75	// nmethod (for lookup purposes) in which case the table cannot be
duke@435	76	// modified.
duke@435	77
duke@435	78	class nmethod;
duke@435	79	class ExceptionHandlerTable VALUE_OBJ_CLASS_SPEC {
duke@435	80	private:
duke@435	81	HandlerTableEntry* _table; // the table
duke@435	82	int _length; // the current length of the table
duke@435	83	int _size; // the number of allocated entries
duke@435	84	ReallocMark _nesting; // assertion check for reallocations
duke@435	85
duke@435	86	// add the entry & grow the table if needed
duke@435	87	void add_entry(HandlerTableEntry entry);
duke@435	88	HandlerTableEntry* subtable_for(int catch_pco) const;
duke@435	89
duke@435	90	public:
duke@435	91	// (compile-time) construction within compiler
duke@435	92	ExceptionHandlerTable(int initial_size = 8);
duke@435	93
duke@435	94	// (run-time) construction from nmethod
duke@435	95	ExceptionHandlerTable(const nmethod* nm);
duke@435	96
duke@435	97	// (compile-time) add entries
duke@435	98	void add_subtable(
duke@435	99	int catch_pco, // the pc offset for the CatchNode
duke@435	100	GrowableArray<intptr_t>* handler_bcis, // the exception handler entry point bcis
duke@435	101	GrowableArray<intptr_t>* scope_depths_from_top_scope,
duke@435	102	// if representing exception handlers in multiple
duke@435	103	// inlined scopes, indicates which scope relative to
duke@435	104	// the youngest/innermost one in which we are performing
duke@435	105	// the lookup; zero (or null GrowableArray) indicates
duke@435	106	// innermost scope
duke@435	107	GrowableArray<intptr_t>* handler_pcos // pc offsets for the compiled handlers
duke@435	108	);
duke@435	109
duke@435	110	// nmethod support
duke@435	111	int size_in_bytes() const { return round_to(_length * sizeof(HandlerTableEntry), oopSize); }
duke@435	112	void copy_to(nmethod* nm);
duke@435	113
duke@435	114	// lookup
duke@435	115	HandlerTableEntry* entry_for(int catch_pco, int handler_bci, int scope_depth) const;
duke@435	116
duke@435	117	// debugging
duke@435	118	void print_subtable(HandlerTableEntry* t) const;
duke@435	119	void print() const;
duke@435	120	void print_subtable_for(int catch_pco) const;
duke@435	121	};
duke@435	122
duke@435	123
duke@435	124	// ----------------------------------------------------------------------------
duke@435	125	// Implicit null exception tables. Maps an exception PC offset to a
duke@435	126	// continuation PC offset. During construction it's a variable sized
duke@435	127	// array with a max size and current length. When stored inside an
duke@435	128	// nmethod a zero length table takes no space. This is detected by
duke@435	129	// nul_chk_table_size() == 0. Otherwise the table has a length word
duke@435	130	// followed by pairs of <excp-offset, const-offset>.
duke@435	131
duke@435	132	// Use 32-bit representation for offsets
duke@435	133	typedef uint implicit_null_entry;
duke@435	134
duke@435	135	class ImplicitExceptionTable VALUE_OBJ_CLASS_SPEC {
duke@435	136	uint _size;
duke@435	137	uint _len;
duke@435	138	implicit_null_entry *_data;
duke@435	139	implicit_null_entry *adr( uint idx ) const { return &_data[2*idx]; }
duke@435	140	ReallocMark _nesting; // assertion check for reallocations
duke@435	141	public:
duke@435	142	ImplicitExceptionTable( ) : _data(0), _size(0), _len(0) { }
duke@435	143	// (run-time) construction from nmethod
duke@435	144	ImplicitExceptionTable( const nmethod *nm );
duke@435	145
duke@435	146	void set_size( uint size );
duke@435	147	void append( uint exec_off, uint cont_off );
duke@435	148	uint at( uint exec_off ) const;
duke@435	149
duke@435	150	uint len() const { return _len; }
duke@435	151	int size_in_bytes() const { return len() == 0 ? 0 : ((2 * len() + 1) * sizeof(implicit_null_entry)); }
duke@435	152
duke@435	153	void copy_to(nmethod* nm);
duke@435	154	void print(address base) const;
duke@435	155	void verify(nmethod *nm) const;
duke@435	156	};