| /* |
| * Copyright 2016, The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| #include <stdint.h> |
| #include <stdio.h> |
| |
| #include "apf.h" |
| |
| // If "c" is of a signed type, generate a compile warning that gets promoted to an error. |
| // This makes bounds checking simpler because ">= 0" can be avoided. Otherwise adding |
| // superfluous ">= 0" with unsigned expressions generates compile warnings. |
| #define ENFORCE_UNSIGNED(c) ((c)==(uint32_t)(c)) |
| |
| static int print_opcode(const char* opcode, char* output_buffer, |
| int output_buffer_len, int offset) { |
| int ret = snprintf(output_buffer + offset, output_buffer_len - offset, |
| "%-6s", opcode); |
| return ret; |
| } |
| |
| // Mapping from opcode number to opcode name. |
| static const char* opcode_names [] = { |
| [LDB_OPCODE] = "ldb", |
| [LDH_OPCODE] = "ldh", |
| [LDW_OPCODE] = "ldw", |
| [LDBX_OPCODE] = "ldbx", |
| [LDHX_OPCODE] = "ldhx", |
| [LDWX_OPCODE] = "ldwx", |
| [ADD_OPCODE] = "add", |
| [MUL_OPCODE] = "mul", |
| [DIV_OPCODE] = "div", |
| [AND_OPCODE] = "and", |
| [OR_OPCODE] = "or", |
| [SH_OPCODE] = "sh", |
| [LI_OPCODE] = "li", |
| [JMP_OPCODE] = "jmp", |
| [JEQ_OPCODE] = "jeq", |
| [JNE_OPCODE] = "jne", |
| [JGT_OPCODE] = "jgt", |
| [JLT_OPCODE] = "jlt", |
| [JSET_OPCODE] = "jset", |
| [JNEBS_OPCODE] = "jnebs", |
| [LDDW_OPCODE] = "lddw", |
| [STDW_OPCODE] = "stdw", |
| }; |
| |
| static int print_jump_target(uint32_t target, uint32_t program_len, |
| char* output_buffer, int output_buffer_len, |
| int offset) { |
| int ret; |
| if (target == program_len) { |
| ret = snprintf(output_buffer + offset, output_buffer_len - offset, |
| "PASS"); |
| } else if (target == program_len + 1) { |
| ret = snprintf(output_buffer + offset, output_buffer_len - offset, |
| "DROP"); |
| } else { |
| ret = snprintf(output_buffer + offset, output_buffer_len - offset, |
| "%u", target); |
| } |
| return ret; |
| } |
| |
| uint32_t apf_disassemble(const uint8_t* program, uint32_t program_len, |
| uint32_t pc, char* output_buffer, |
| int output_buffer_len) { |
| if (pc > program_len + 1) { |
| fprintf(stderr, "pc is overflow: pc %d, program_len: %d", pc, |
| program_len); |
| return pc; |
| } |
| #define ASSERT_RET_INBOUND(x) \ |
| if ((x) < 0 || (x) >= (output_buffer_len - offset)) return pc + 2 |
| |
| int offset = 0; |
| int ret; |
| ret = snprintf(output_buffer + offset, output_buffer_len - offset, |
| "%8u: ", pc); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| |
| if (pc == program_len) { |
| ret = snprintf(output_buffer + offset, output_buffer_len - offset, |
| "PASS"); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| return ++pc; |
| } |
| |
| if (pc == program_len + 1) { |
| ret = snprintf(output_buffer + offset, output_buffer_len - offset, |
| "DROP"); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| return ++pc; |
| } |
| |
| const uint8_t bytecode = program[pc++]; |
| const uint32_t opcode = EXTRACT_OPCODE(bytecode); |
| #define PRINT_OPCODE() \ |
| print_opcode(opcode_names[opcode], output_buffer, output_buffer_len, offset) |
| const uint32_t reg_num = EXTRACT_REGISTER(bytecode); |
| // All instructions have immediate fields, so load them now. |
| const uint32_t len_field = EXTRACT_IMM_LENGTH(bytecode); |
| uint32_t imm = 0; |
| int32_t signed_imm = 0; |
| if (len_field != 0) { |
| const uint32_t imm_len = 1 << (len_field - 1); |
| for (uint32_t i = 0; i < imm_len && pc < program_len; i++) |
| imm = (imm << 8) | program[pc++]; |
| // Sign extend imm into signed_imm. |
| signed_imm = imm << ((4 - imm_len) * 8); |
| signed_imm >>= (4 - imm_len) * 8; |
| } |
| switch (opcode) { |
| case LDB_OPCODE: |
| case LDH_OPCODE: |
| case LDW_OPCODE: |
| ret = PRINT_OPCODE(); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| ret = snprintf(output_buffer + offset, output_buffer_len - offset, |
| "r%d, [%u]", reg_num, imm); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| break; |
| case LDBX_OPCODE: |
| case LDHX_OPCODE: |
| case LDWX_OPCODE: |
| ret = PRINT_OPCODE(); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| if (imm) { |
| ret = |
| snprintf(output_buffer + offset, output_buffer_len - offset, |
| "r%d, [r1+%u]", reg_num, imm); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } else { |
| ret = |
| snprintf(output_buffer + offset, output_buffer_len - offset, |
| "r%d, [r1]", reg_num); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } |
| break; |
| case JMP_OPCODE: |
| ret = PRINT_OPCODE(); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| ret = print_jump_target(pc + imm, program_len, output_buffer, |
| output_buffer_len, offset); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| break; |
| case JEQ_OPCODE: |
| case JNE_OPCODE: |
| case JGT_OPCODE: |
| case JLT_OPCODE: |
| case JSET_OPCODE: |
| case JNEBS_OPCODE: { |
| ret = PRINT_OPCODE(); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| ret = snprintf(output_buffer + offset, output_buffer_len - offset, |
| "r0, "); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| // Load second immediate field. |
| uint32_t cmp_imm = 0; |
| if (reg_num == 1) { |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "r1, "); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } else if (len_field == 0) { |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "0, "); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } else { |
| uint32_t cmp_imm_len = 1 << (len_field - 1); |
| uint32_t i; |
| for (i = 0; i < cmp_imm_len && pc < program_len; i++) |
| cmp_imm = (cmp_imm << 8) | program[pc++]; |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "0x%x, ", cmp_imm); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } |
| if (opcode == JNEBS_OPCODE) { |
| ret = print_jump_target(pc + imm + cmp_imm, program_len, |
| output_buffer, output_buffer_len, offset); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, ", "); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| while (cmp_imm--) { |
| uint8_t byte = program[pc++]; |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "%02x", byte); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } |
| } else { |
| ret = print_jump_target(pc + imm, program_len, output_buffer, |
| output_buffer_len, offset); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } |
| break; |
| } |
| case SH_OPCODE: |
| ret = PRINT_OPCODE(); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| if (reg_num) { |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "r0, r1"); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } else { |
| ret = |
| snprintf(output_buffer + offset, output_buffer_len - offset, |
| "r0, %d", signed_imm); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } |
| break; |
| case ADD_OPCODE: |
| case MUL_OPCODE: |
| case DIV_OPCODE: |
| case AND_OPCODE: |
| case OR_OPCODE: |
| ret = PRINT_OPCODE(); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| if (reg_num) { |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "r0, r1"); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } else if (!imm && opcode == DIV_OPCODE) { |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "pass (div 0)"); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } else { |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "r0, %u", imm); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } |
| break; |
| case LI_OPCODE: |
| ret = PRINT_OPCODE(); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| ret = snprintf(output_buffer + offset, output_buffer_len - offset, |
| "r%d, %d", reg_num, signed_imm); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| break; |
| case EXT_OPCODE: |
| if ( |
| // If LDM_EXT_OPCODE is 0 and imm is compared with it, a compiler error will result, |
| // instead just enforce that imm is unsigned (so it's always greater or equal to 0). |
| #if LDM_EXT_OPCODE == 0 |
| ENFORCE_UNSIGNED(imm) && |
| #else |
| imm >= LDM_EXT_OPCODE && |
| #endif |
| imm < (LDM_EXT_OPCODE + MEMORY_ITEMS)) { |
| ret = print_opcode("ldm", output_buffer, output_buffer_len, |
| offset); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| ret = |
| snprintf(output_buffer + offset, output_buffer_len - offset, |
| "r%d, m[%u]", reg_num, imm - LDM_EXT_OPCODE); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } else if (imm >= STM_EXT_OPCODE && imm < (STM_EXT_OPCODE + MEMORY_ITEMS)) { |
| ret = print_opcode("stm", output_buffer, output_buffer_len, |
| offset); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| ret = |
| snprintf(output_buffer + offset, output_buffer_len - offset, |
| "r%d, m[%u]", reg_num, imm - STM_EXT_OPCODE); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } else switch (imm) { |
| case NOT_EXT_OPCODE: |
| ret = print_opcode("not", output_buffer, |
| output_buffer_len, offset); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "r%d", |
| reg_num); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| break; |
| case NEG_EXT_OPCODE: |
| ret = print_opcode("neg", output_buffer, output_buffer_len, |
| offset); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "r%d", reg_num); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| break; |
| case SWAP_EXT_OPCODE: |
| ret = print_opcode("swap", output_buffer, output_buffer_len, |
| offset); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| break; |
| case MOV_EXT_OPCODE: |
| ret = print_opcode("mov", output_buffer, output_buffer_len, |
| offset); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "r%d, r%d", |
| reg_num, reg_num ^ 1); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| break; |
| default: |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "unknown_ext %u", |
| imm); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| break; |
| } |
| break; |
| case LDDW_OPCODE: |
| case STDW_OPCODE: |
| ret = PRINT_OPCODE(); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| if (signed_imm > 0) { |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "r%u, [r%u+%d]", reg_num, |
| reg_num ^ 1, signed_imm); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } else if (signed_imm < 0) { |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "r%u, [r%u-%d]", |
| reg_num, reg_num ^ 1, -signed_imm); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } else { |
| ret = snprintf(output_buffer + offset, |
| output_buffer_len - offset, "r%u, [r%u]", reg_num, |
| reg_num ^ 1); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| } |
| break; |
| |
| // Unknown opcode |
| default: |
| ret = snprintf(output_buffer + offset, output_buffer_len - offset, |
| "unknown %u", opcode); |
| ASSERT_RET_INBOUND(ret); |
| offset += ret; |
| break; |
| } |
| return pc; |
| } |
