/* * Copyright (C) 2011 Apple Inc. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #ifndef DFGCorrectableJumpPoint_h #define DFGCorrectableJumpPoint_h #if ENABLE(DFG_JIT) #include "LinkBuffer.h" #include "MacroAssembler.h" namespace JSC { namespace DFG { // This is a type-safe union of MacroAssembler::Jump and CodeLocationJump. // Furthermore, it supports the notion of branching (possibly conditionally, but // also possibly jumping unconditionally) to an out-of-line patchable jump. // Thus it goes through three states: // // 1) Label of unpatchable branch or jump (i.e. MacroAssembler::Jump). // 2) Label of patchable jump (i.e. MacroAssembler::PatchableJump). // 3) Corrected post-linking label of patchable jump (i.e. CodeLocationJump). // // The setting of state (1) corresponds to planting the in-line unpatchable // branch or jump. The state transition (1)->(2) corresponds to linking the // in-line branch or jump to the out-of-line patchable jump, and recording // the latter's label. The state transition (2)->(3) corresponds to recording // the out-of-line patchable jump's location after branch compaction has // completed. // // You can also go directly from the first state to the third state, if you // wish to use this class for in-line patchable jumps. class CorrectableJumpPoint { public: CorrectableJumpPoint(MacroAssembler::Jump check) : m_codeOffset(check.m_label.m_offset) #ifndef NDEBUG , m_mode(InitialJump) #endif { #if CPU(ARM_THUMB2) m_type = check.m_type; m_condition = check.m_condition; #endif } void switchToLateJump(MacroAssembler::PatchableJump check) { #ifndef NDEBUG ASSERT(m_mode == InitialJump); m_mode = LateJump; #endif // Late jumps should only ever be real jumps. #if CPU(ARM_THUMB2) ASSERT(check.m_jump.m_type == ARMv7Assembler::JumpNoConditionFixedSize); ASSERT(check.m_jump.m_condition == ARMv7Assembler::ConditionInvalid); m_type = ARMv7Assembler::JumpNoConditionFixedSize; m_condition = ARMv7Assembler::ConditionInvalid; #endif m_codeOffset = check.m_jump.m_label.m_offset; } void correctInitialJump(LinkBuffer& linkBuffer) { ASSERT(m_mode == InitialJump); #if CPU(ARM_THUMB2) ASSERT(m_type == ARMv7Assembler::JumpNoConditionFixedSize); ASSERT(m_condition == ARMv7Assembler::ConditionInvalid); #endif correctJump(linkBuffer); } void correctLateJump(LinkBuffer& linkBuffer) { ASSERT(m_mode == LateJump); correctJump(linkBuffer); } MacroAssembler::Jump initialJump() const { ASSERT(m_mode == InitialJump); return getJump(); } MacroAssembler::Jump lateJump() const { ASSERT(m_mode == LateJump); return getJump(); } CodeLocationJump codeLocationForRepatch(CodeBlock*) const; private: void correctJump(LinkBuffer& linkBuffer) { #ifndef NDEBUG m_mode = CorrectedJump; #endif MacroAssembler::Label label; label.m_label.m_offset = m_codeOffset; m_codeOffset = linkBuffer.offsetOf(label); } MacroAssembler::Jump getJump() const { MacroAssembler::Jump jump; jump.m_label.m_offset = m_codeOffset; #if CPU(ARM_THUMB2) jump.m_type = m_type; jump.m_condition = m_condition; #endif return jump; } unsigned m_codeOffset; #if CPU(ARM_THUMB2) ARMv7Assembler::JumpType m_type : 8; ARMv7Assembler::Condition m_condition : 8; #endif #ifndef NDEBUG enum Mode { InitialJump, LateJump, CorrectedJump }; Mode m_mode; #endif }; } } // namespace JSC::DFG #endif // ENABLE(DFG_JIT) #endif // DFGCorrectableJumpPoint_h