| /* |
| * Copyright (c) 2016, Oracle and/or its affiliates. All rights reserved. |
| * Copyright (c) 2016 SAP SE. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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| */ |
| |
| #ifndef CPU_S390_VM_RELOCINFO_S390_HPP |
| #define CPU_S390_VM_RELOCINFO_S390_HPP |
| |
| //---------------------------- |
| // relocInfo layout |
| //---------------------------- |
| |
| // This description should be contained in code/relocInfo.hpp |
| // but was put here to minimize shared code diffs. |
| |
| // Relocation information for a nmethod is stored in compressed |
| // form in an array of element type short int (16 bits). |
| // Each array element constitutes one relocInfo record. |
| // The layout of one such record is described here. |
| |
| // +------------+---+---+------------------------------+ |
| // | type | fmt | offset/offset_unit | |
| // +------------+---+---+------------------------------+ |
| // |
| // |<-- value_width (16) ----------------------------->| |
| // |<type_width>|<-- nontype_width (12) -------------->| |
| // (4) |
| // | |<--+-->|<-- offset_width (10) ------->| |
| // / \ |
| // / (2) \ |
| // /<--format->\ |
| // | width | |
| |
| |
| // only for type == data_prefix_tag: |
| // +------------+---+---+------------------------------+ |
| // | type | | data | |
| // +------------+---+---+------------------------------+ |
| // | 15 |<->|<-- datalen_width (11) ---------->| |
| // | |
| // +--datalen_tag (1) |
| |
| // relocType |
| // The type field holds a value of relocType (which is |
| // an enum of all possible relocation types). Currently, |
| // there are 16 distinct relocation types, requiring |
| // type_width to be (at least) 4. |
| // relocFormat |
| // The format field holds a value of relocFormat (which is |
| // an enum of all possible relocation formats). Currently, |
| // there are 4 distinct relocation formats, requiring |
| // format_width to be (at least) 2. |
| // offset |
| // Each relocInfo is related to one specific address in the CodeBlob. |
| // The address always points to the first byte of the target instruction. |
| // It does NOT refer directly to the relocation subfield or embedded constant. |
| // offset contains the distance of this relocInfo from the previous one. |
| // offset is scaled by offset_unit (the platform-specific instruction |
| // alignment requirement) to maximize the encodable distance. |
| // To obtain the absolute address in the CodeBlob the relocInfo is |
| // related to, you have to iterate over all relocInfos from the |
| // beginning, and then use RelocIterator::addr() to get the address. |
| |
| // relocType == data_prefix_tag |
| // These are relocInfo records containing inline data that belongs to |
| // the next non-data relocInfo record. Usage of that inline data is |
| // specific and private to that relocInfo record. |
| // For details refer to code/relocInfo.hpp |
| |
| |
| // machine-dependent parts of class relocInfo |
| private: |
| enum { |
| // Instructions are HW (2-byte) aligned on z/Architecture. |
| offset_unit = 2, |
| |
| // Encodes Assembler::disp32_operand vs. Assembler::imm64_operand. |
| // (Assembler::call32_operand is used on call instructions only.) |
| format_width = 2 |
| }; |
| |
| public: |
| |
| enum relocFormat { |
| no_format = 0, |
| uncompressed_format = 0, // Relocation is for a regular oop. |
| compressed_format = 1, // Relocation is for a narrow (compressed) oop or klass. |
| // Similar to relocInfo::narrow_oop_in_const. |
| pcrel_addr_format = 2, // Relocation is for the target LOCATION of a pc-relative instruction. |
| pcrel_data_format = 3 // Relocation is for the target data of a pc-relative instruction. |
| }; |
| |
| // Store the new target address into an oop_Relocation cell, if any. |
| // Return indication if update happened. |
| static bool update_oop_pool(address begin, address end, address newTarget, CodeBlob* cb); |
| |
| #endif // CPU_S390_VM_RELOCINFO_S390_HPP |