1 /* 2 * Generic intermediate code generation. 3 * 4 * Copyright (C) 2016-2017 Lluís Vilanova <vilanova@ac.upc.edu> 5 * 6 * This work is licensed under the terms of the GNU GPL, version 2 or later. 7 * See the COPYING file in the top-level directory. 8 */ 9 10 #include "qemu/osdep.h" 11 #include "qemu-common.h" 12 #include "qemu/error-report.h" 13 #include "cpu.h" 14 #include "tcg/tcg.h" 15 #include "tcg/tcg-op.h" 16 #include "exec/exec-all.h" 17 #include "exec/gen-icount.h" 18 #include "exec/log.h" 19 #include "exec/translator.h" 20 21 /* Pairs with tcg_clear_temp_count. 22 To be called by #TranslatorOps.{translate_insn,tb_stop} if 23 (1) the target is sufficiently clean to support reporting, 24 (2) as and when all temporaries are known to be consumed. 25 For most targets, (2) is at the end of translate_insn. */ 26 void translator_loop_temp_check(DisasContextBase *db) 27 { 28 if (tcg_check_temp_count()) { 29 qemu_log("warning: TCG temporary leaks before " 30 TARGET_FMT_lx "\n", db->pc_next); 31 } 32 } 33 34 void translator_loop(const TranslatorOps *ops, DisasContextBase *db, 35 CPUState *cpu, TranslationBlock *tb) 36 { 37 /* Initialize DisasContext */ 38 db->tb = tb; 39 db->pc_first = tb->pc; 40 db->pc_next = db->pc_first; 41 db->is_jmp = DISAS_NEXT; 42 db->num_insns = 0; 43 db->singlestep_enabled = cpu->singlestep_enabled; 44 45 /* Instruction counting */ 46 db->max_insns = tb_cflags(db->tb) & CF_COUNT_MASK; 47 if (db->max_insns == 0) { 48 db->max_insns = CF_COUNT_MASK; 49 } 50 if (db->max_insns > TCG_MAX_INSNS) { 51 db->max_insns = TCG_MAX_INSNS; 52 } 53 if (db->singlestep_enabled || singlestep) { 54 db->max_insns = 1; 55 } 56 57 ops->init_disas_context(db, cpu); 58 tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */ 59 60 /* Reset the temp count so that we can identify leaks */ 61 tcg_clear_temp_count(); 62 63 /* Start translating. */ 64 gen_tb_start(db->tb); 65 ops->tb_start(db, cpu); 66 tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */ 67 68 while (true) { 69 db->num_insns++; 70 ops->insn_start(db, cpu); 71 tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */ 72 73 /* Pass breakpoint hits to target for further processing */ 74 if (unlikely(!QTAILQ_EMPTY(&cpu->breakpoints))) { 75 CPUBreakpoint *bp; 76 QTAILQ_FOREACH(bp, &cpu->breakpoints, entry) { 77 if (bp->pc == db->pc_next) { 78 if (ops->breakpoint_check(db, cpu, bp)) { 79 break; 80 } 81 } 82 } 83 /* The breakpoint_check hook may use DISAS_TOO_MANY to indicate 84 that only one more instruction is to be executed. Otherwise 85 it should use DISAS_NORETURN when generating an exception, 86 but may use a DISAS_TARGET_* value for Something Else. */ 87 if (db->is_jmp > DISAS_TOO_MANY) { 88 break; 89 } 90 } 91 92 /* Disassemble one instruction. The translate_insn hook should 93 update db->pc_next and db->is_jmp to indicate what should be 94 done next -- either exiting this loop or locate the start of 95 the next instruction. */ 96 if (db->num_insns == db->max_insns 97 && (tb_cflags(db->tb) & CF_LAST_IO)) { 98 /* Accept I/O on the last instruction. */ 99 gen_io_start(); 100 ops->translate_insn(db, cpu); 101 gen_io_end(); 102 } else { 103 ops->translate_insn(db, cpu); 104 } 105 106 /* Stop translation if translate_insn so indicated. */ 107 if (db->is_jmp != DISAS_NEXT) { 108 break; 109 } 110 111 /* Stop translation if the output buffer is full, 112 or we have executed all of the allowed instructions. */ 113 if (tcg_op_buf_full() || db->num_insns >= db->max_insns) { 114 db->is_jmp = DISAS_TOO_MANY; 115 break; 116 } 117 } 118 119 /* Emit code to exit the TB, as indicated by db->is_jmp. */ 120 ops->tb_stop(db, cpu); 121 gen_tb_end(db->tb, db->num_insns); 122 123 /* The disas_log hook may use these values rather than recompute. */ 124 db->tb->size = db->pc_next - db->pc_first; 125 db->tb->icount = db->num_insns; 126 127 #ifdef DEBUG_DISAS 128 if (qemu_loglevel_mask(CPU_LOG_TB_IN_ASM) 129 && qemu_log_in_addr_range(db->pc_first)) { 130 qemu_log_lock(); 131 qemu_log("----------------\n"); 132 ops->disas_log(db, cpu); 133 qemu_log("\n"); 134 qemu_log_unlock(); 135 } 136 #endif 137 } 138