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Diffstat (limited to 'js/src/methodjit/ICRepatcher.h')
| -rw-r--r-- | js/src/methodjit/ICRepatcher.h | 164 |
1 files changed, 164 insertions, 0 deletions
diff --git a/js/src/methodjit/ICRepatcher.h b/js/src/methodjit/ICRepatcher.h new file mode 100644 index 0000000..59d8e78 --- /dev/null +++ b/js/src/methodjit/ICRepatcher.h @@ -0,0 +1,164 @@ +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- + * vim: set ts=4 sw=4 et tw=99: + * + * ***** BEGIN LICENSE BLOCK ***** + * Version: MPL 1.1/GPL 2.0/LGPL 2.1 + * + * The contents of this file are subject to the Mozilla Public License Version + * 1.1 (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * http://www.mozilla.org/MPL/ + * + * Software distributed under the License is distributed on an "AS IS" basis, + * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License + * for the specific language governing rights and limitations under the + * License. + * + * The Original Code is Mozilla SpiderMonkey JavaScript 1.9 code, released + * May 28, 2008. + * + * The Initial Developer of the Original Code is + * Brendan Eich <brendan@mozilla.org> + * + * Contributor(s): + * David Mandelin <dmandelin@mozilla.com> + * David Anderson <danderson@mozilla.com> + * Chris Leary <cdleary@mozilla.com> + * Jacob Bramley <Jacob.Bramely@arm.com> + * + * Alternatively, the contents of this file may be used under the terms of + * either of the GNU General Public License Version 2 or later (the "GPL"), + * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), + * in which case the provisions of the GPL or the LGPL are applicable instead + * of those above. If you wish to allow use of your version of this file only + * under the terms of either the GPL or the LGPL, and not to allow others to + * use your version of this file under the terms of the MPL, indicate your + * decision by deleting the provisions above and replace them with the notice + * and other provisions required by the GPL or the LGPL. If you do not delete + * the provisions above, a recipient may use your version of this file under + * the terms of any one of the MPL, the GPL or the LGPL. + * + * ***** END LICENSE BLOCK ***** */ + +#if !defined jsjaeger_icrepatcher_h__ && defined JS_METHODJIT +#define jsjaeger_icrepatcher_h__ + +#include "assembler/assembler/RepatchBuffer.h" +#include "assembler/moco/MocoStubs.h" +#include "methodjit/ICChecker.h" + +namespace js { +namespace mjit { +namespace ic { + +class Repatcher : public JSC::RepatchBuffer +{ + typedef JSC::CodeLocationLabel CodeLocationLabel; + typedef JSC::CodeLocationCall CodeLocationCall; + typedef JSC::FunctionPtr FunctionPtr; + + CodeLocationLabel label; + + public: + explicit Repatcher(JITScript *js) + : JSC::RepatchBuffer(js->code), label(js->code.m_code.executableAddress()) + { } + + explicit Repatcher(const JSC::JITCode &code) + : JSC::RepatchBuffer(code), label(code.start()) + { } + + using JSC::RepatchBuffer::relink; + + /* Patch a stub call. */ + void relink(CodeLocationCall call, FunctionPtr stub) { +#if defined JS_CPU_X64 || defined JS_CPU_X86 + JSC::RepatchBuffer::relink(call, stub); +#elif defined JS_CPU_ARM + /* + * Stub calls on ARM look like this: + * + * ldr ip, =stub + * call label -> ldr r8, =JaegerStubVeneer + * blx r8 + * + * ARM has to run stub calls through a veneer in order for THROW to + * work properly. The address that must be patched is the load into + * 'ip', not the load into 'r8'. + */ + CheckIsStubCall(call.labelAtOffset(0)); + JSC::RepatchBuffer::relink(call.callAtOffset(-4), stub); +#else +# error +#endif + } + + /* Patch the offset of a Value load emitted by loadValueWithAddressOffsetPatch. */ + void patchAddressOffsetForValueLoad(CodeLocationLabel label, uint32 offset) { +#if defined JS_CPU_X64 || defined JS_CPU_ARM + repatch(label.dataLabel32AtOffset(0), offset); +#elif defined JS_CPU_X86 + static const unsigned LOAD_TYPE_OFFSET = 6; + static const unsigned LOAD_DATA_OFFSET = 12; + + /* + * We have the following sequence to patch: + * + * mov <offset+4>($base), %<type> + * mov <offset+0>($base), %<data> + */ + repatch(label.dataLabel32AtOffset(LOAD_DATA_OFFSET), offset); + repatch(label.dataLabel32AtOffset(LOAD_TYPE_OFFSET), offset + 4); +#else +# error +#endif + } + + void patchAddressOffsetForValueStore(CodeLocationLabel label, uint32 offset, bool typeConst) { +#if defined JS_CPU_ARM || defined JS_CPU_X64 + (void) typeConst; + repatch(label.dataLabel32AtOffset(0), offset); +#elif defined JS_CPU_X86 + static const unsigned STORE_TYPE_OFFSET = 6; + static const unsigned STORE_DATA_CONST_TYPE_OFFSET = 16; + static const unsigned STORE_DATA_TYPE_OFFSET = 12; + + /* + * The type is stored first, then the payload. Both stores can vary in + * size, depending on whether or not the data is a constant in the + * instruction stream (though only the first store matters for the + * purpose of locating both offsets for patching). + * + * We have one of the following sequences to patch. Offsets are located + * before 6B into a given move instruction, but the mov instructions + * carrying constant payloads are 10B wide overall. + * + * typeConst=false, dataConst=false + * mov %<type>, <offset+4>($base) ; Length is 6 + * mov %<data>, <offset+0>($base) ; Offset @ len(prev) + 6 = 12 + * typeConst=true, dataConst=false + * mov $<type>, <offset+4>($base) ; Length is 10 + * mov %<data>, <offset+0>($base) ; Offset @ len(prev) + 6 = 16 + * typeConst=true, dataConst=true + * mov $<type>, <offset+4>($base) ; Length is 10 + * mov $<data>, <offset+0>($base) ; Offset @ len(prev) + 6 = 16 + * + * Note that we only need to know whether type is const to determine the + * correct patch offsets. In all cases, the label points to the start + * of the sequence. + */ + repatch(label.dataLabel32AtOffset(STORE_TYPE_OFFSET), offset + 4); + + unsigned payloadOffset = typeConst ? STORE_DATA_CONST_TYPE_OFFSET : STORE_DATA_TYPE_OFFSET; + repatch(label.dataLabel32AtOffset(payloadOffset), offset); +#else +# error +#endif + } +}; + +} /* namespace ic */ +} /* namespace mjit */ +} /* namespace js */ + +#endif |