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/js/src/methodjit/ICRepatcher.h

http://github.com/zpao/v8monkey
C Header | 181 lines | 66 code | 16 blank | 99 comment | 9 complexity | 978dfd1964e5ca92269d68d71c6a6b79 MD5 | raw file
  1/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
  2 * vim: set ts=4 sw=4 et tw=99:
  3 *
  4 * ***** BEGIN LICENSE BLOCK *****
  5 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  6 *
  7 * The contents of this file are subject to the Mozilla Public License Version
  8 * 1.1 (the "License"); you may not use this file except in compliance with
  9 * the License. You may obtain a copy of the License at
 10 * http://www.mozilla.org/MPL/
 11 *
 12 * Software distributed under the License is distributed on an "AS IS" basis,
 13 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 14 * for the specific language governing rights and limitations under the
 15 * License.
 16 *
 17 * The Original Code is Mozilla SpiderMonkey JavaScript 1.9 code, released
 18 * May 28, 2008.
 19 *
 20 * The Initial Developer of the Original Code is
 21 *   Brendan Eich <brendan@mozilla.org>
 22 *
 23 * Contributor(s):
 24 *   David Mandelin <dmandelin@mozilla.com>
 25 *   David Anderson <danderson@mozilla.com>
 26 *   Chris Leary <cdleary@mozilla.com>
 27 *   Jacob Bramley <Jacob.Bramely@arm.com>
 28 *
 29 * Alternatively, the contents of this file may be used under the terms of
 30 * either of the GNU General Public License Version 2 or later (the "GPL"),
 31 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 32 * in which case the provisions of the GPL or the LGPL are applicable instead
 33 * of those above. If you wish to allow use of your version of this file only
 34 * under the terms of either the GPL or the LGPL, and not to allow others to
 35 * use your version of this file under the terms of the MPL, indicate your
 36 * decision by deleting the provisions above and replace them with the notice
 37 * and other provisions required by the GPL or the LGPL. If you do not delete
 38 * the provisions above, a recipient may use your version of this file under
 39 * the terms of any one of the MPL, the GPL or the LGPL.
 40 *
 41 * ***** END LICENSE BLOCK ***** */
 42
 43#if !defined jsjaeger_icrepatcher_h__ && defined JS_METHODJIT
 44#define jsjaeger_icrepatcher_h__
 45
 46#include "assembler/assembler/RepatchBuffer.h"
 47#include "assembler/moco/MocoStubs.h"
 48#include "methodjit/ICChecker.h"
 49
 50namespace js {
 51namespace mjit {
 52namespace ic {
 53
 54class Repatcher : public JSC::RepatchBuffer
 55{
 56    typedef JSC::CodeLocationLabel  CodeLocationLabel;
 57    typedef JSC::CodeLocationCall   CodeLocationCall;
 58    typedef JSC::FunctionPtr        FunctionPtr;
 59
 60    CodeLocationLabel label;
 61
 62  public:
 63    explicit Repatcher(JITChunk *js)
 64      : JSC::RepatchBuffer(js->code), label(js->code.m_code.executableAddress())
 65    { }
 66
 67    explicit Repatcher(const JSC::JITCode &code)
 68      : JSC::RepatchBuffer(code), label(code.start())
 69    { }
 70
 71    using JSC::RepatchBuffer::relink;
 72
 73    /* Patch a stub call. */
 74    void relink(CodeLocationCall call, FunctionPtr stub) {
 75#if defined JS_CPU_X64 || defined JS_CPU_X86 || defined JS_CPU_SPARC
 76        JSC::RepatchBuffer::relink(call, stub);
 77#elif defined JS_CPU_ARM
 78        /*
 79         * Stub calls on ARM look like this:
 80         *
 81         *                  ldr     ip, =stub
 82         * call label ->    ldr     r8, =JaegerStubVeneer
 83         *                  blx     r8
 84         *
 85         * ARM has to run stub calls through a veneer in order for THROW to
 86         * work properly. The address that must be patched is the load into
 87         * 'ip', not the load into 'r8'.
 88         */
 89        CheckIsStubCall(call.labelAtOffset(0));
 90        JSC::RepatchBuffer::relink(call.callAtOffset(-4), stub);
 91#elif defined JS_CPU_MIPS
 92        /*
 93         * Stub calls on MIPS look like this:
 94         *
 95         *                  lui     v0, hi(stub)
 96         *                  ori     v0, v0, lo(stub)
 97         *                  lui     t9, hi(JaegerStubVeneer)
 98         *                  ori     t9, t9, lo(JaegerStubVeneer)
 99         *                  jalr    t9
100         *                  nop
101         * call label ->    xxx
102         *
103         * MIPS has to run stub calls through a veneer in order for THROW to
104         * work properly. The address that must be patched is the load into
105         * 'v0', not the load into 't9'.
106         */
107        JSC::RepatchBuffer::relink(call.callAtOffset(-8), stub);
108#else
109# error
110#endif
111    }
112
113    /* Patch the offset of a Value load emitted by loadValueWithAddressOffsetPatch. */
114    void patchAddressOffsetForValueLoad(CodeLocationLabel label, uint32_t offset) {
115#if defined JS_CPU_X64 || defined JS_CPU_ARM || defined JS_CPU_SPARC || defined JS_CPU_MIPS 
116        repatch(label.dataLabel32AtOffset(0), offset);
117#elif defined JS_CPU_X86
118        static const unsigned LOAD_TYPE_OFFSET = 6;
119        static const unsigned LOAD_DATA_OFFSET = 12;
120
121        /*
122         * We have the following sequence to patch:
123         *
124         *      mov     <offset+4>($base), %<type>
125         *      mov     <offset+0>($base), %<data>
126         */
127        repatch(label.dataLabel32AtOffset(LOAD_DATA_OFFSET), offset);
128        repatch(label.dataLabel32AtOffset(LOAD_TYPE_OFFSET), offset + 4);
129#else
130# error
131#endif
132    }
133
134    void patchAddressOffsetForValueStore(CodeLocationLabel label, uint32_t offset, bool typeConst) {
135#if defined JS_CPU_ARM || defined JS_CPU_X64 || defined JS_CPU_SPARC || defined JS_CPU_MIPS
136        (void) typeConst;
137        repatch(label.dataLabel32AtOffset(0), offset);
138#elif defined JS_CPU_X86
139        static const unsigned STORE_TYPE_OFFSET = 6;
140        static const unsigned STORE_DATA_CONST_TYPE_OFFSET = 16;
141        static const unsigned STORE_DATA_TYPE_OFFSET = 12;
142
143        /*
144         * The type is stored first, then the payload. Both stores can vary in
145         * size, depending on whether or not the data is a constant in the
146         * instruction stream (though only the first store matters for the
147         * purpose of locating both offsets for patching).
148         *
149         * We have one of the following sequences to patch. Offsets are located
150         * before 6B into a given move instruction, but the mov instructions
151         * carrying constant payloads are 10B wide overall.
152         *
153         *  typeConst=false, dataConst=false
154         *      mov     %<type>, <offset+4>($base)  ; Length is 6
155         *      mov     %<data>, <offset+0>($base)  ; Offset @ len(prev) + 6 = 12
156         *  typeConst=true, dataConst=false
157         *      mov     $<type>, <offset+4>($base)  ; Length is 10
158         *      mov     %<data>, <offset+0>($base)  ; Offset @ len(prev) + 6 = 16
159         *  typeConst=true, dataConst=true
160         *      mov     $<type>, <offset+4>($base)  ; Length is 10
161         *      mov     $<data>, <offset+0>($base)  ; Offset @ len(prev) + 6 = 16
162         *
163         * Note that we only need to know whether type is const to determine the
164         * correct patch offsets. In all cases, the label points to the start
165         * of the sequence.
166         */
167        repatch(label.dataLabel32AtOffset(STORE_TYPE_OFFSET), offset + 4);
168
169        unsigned payloadOffset = typeConst ? STORE_DATA_CONST_TYPE_OFFSET : STORE_DATA_TYPE_OFFSET;
170        repatch(label.dataLabel32AtOffset(payloadOffset), offset);
171#else
172# error
173#endif
174    }
175};
176
177} /* namespace ic */
178} /* namespace mjit */
179} /* namespace js */
180
181#endif