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/error-report.h" 12 #include "tcg/tcg.h" 13 #include "tcg/tcg-op.h" 14 #include "exec/exec-all.h" 15 #include "exec/gen-icount.h" 16 #include "exec/log.h" 17 #include "exec/translator.h" 18 #include "exec/plugin-gen.h" 19 #include "sysemu/replay.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 bool translator_use_goto_tb(DisasContextBase *db, target_ulong dest) 35 { 36 /* Suppress goto_tb in the case of single-steping. */ 37 if (db->singlestep_enabled || singlestep) { 38 return false; 39 } 40 41 /* Check for the dest on the same page as the start of the TB. */ 42 return ((db->pc_first ^ dest) & TARGET_PAGE_MASK) == 0; 43 } 44 45 void translator_loop(const TranslatorOps *ops, DisasContextBase *db, 46 CPUState *cpu, TranslationBlock *tb, int max_insns) 47 { 48 int bp_insn = 0; 49 bool plugin_enabled; 50 51 /* Initialize DisasContext */ 52 db->tb = tb; 53 db->pc_first = tb->pc; 54 db->pc_next = db->pc_first; 55 db->is_jmp = DISAS_NEXT; 56 db->num_insns = 0; 57 db->max_insns = max_insns; 58 db->singlestep_enabled = cpu->singlestep_enabled; 59 60 ops->init_disas_context(db, cpu); 61 tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */ 62 63 /* Reset the temp count so that we can identify leaks */ 64 tcg_clear_temp_count(); 65 66 /* Start translating. */ 67 gen_tb_start(db->tb); 68 ops->tb_start(db, cpu); 69 tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */ 70 71 plugin_enabled = plugin_gen_tb_start(cpu, tb, 72 tb_cflags(db->tb) & CF_MEMI_ONLY); 73 74 while (true) { 75 db->num_insns++; 76 ops->insn_start(db, cpu); 77 tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */ 78 79 if (plugin_enabled) { 80 plugin_gen_insn_start(cpu, db); 81 } 82 83 /* Pass breakpoint hits to target for further processing */ 84 if (!db->singlestep_enabled 85 && unlikely(!QTAILQ_EMPTY(&cpu->breakpoints))) { 86 CPUBreakpoint *bp; 87 QTAILQ_FOREACH(bp, &cpu->breakpoints, entry) { 88 if (bp->pc == db->pc_next) { 89 if (ops->breakpoint_check(db, cpu, bp)) { 90 bp_insn = 1; 91 break; 92 } 93 } 94 } 95 /* The breakpoint_check hook may use DISAS_TOO_MANY to indicate 96 that only one more instruction is to be executed. Otherwise 97 it should use DISAS_NORETURN when generating an exception, 98 but may use a DISAS_TARGET_* value for Something Else. */ 99 if (db->is_jmp > DISAS_TOO_MANY) { 100 break; 101 } 102 } 103 104 /* Disassemble one instruction. The translate_insn hook should 105 update db->pc_next and db->is_jmp to indicate what should be 106 done next -- either exiting this loop or locate the start of 107 the next instruction. */ 108 if (db->num_insns == db->max_insns 109 && (tb_cflags(db->tb) & CF_LAST_IO)) { 110 /* Accept I/O on the last instruction. */ 111 gen_io_start(); 112 ops->translate_insn(db, cpu); 113 } else { 114 /* we should only see CF_MEMI_ONLY for io_recompile */ 115 tcg_debug_assert(!(tb_cflags(db->tb) & CF_MEMI_ONLY)); 116 ops->translate_insn(db, cpu); 117 } 118 119 /* Stop translation if translate_insn so indicated. */ 120 if (db->is_jmp != DISAS_NEXT) { 121 break; 122 } 123 124 /* 125 * We can't instrument after instructions that change control 126 * flow although this only really affects post-load operations. 127 */ 128 if (plugin_enabled) { 129 plugin_gen_insn_end(); 130 } 131 132 /* Stop translation if the output buffer is full, 133 or we have executed all of the allowed instructions. */ 134 if (tcg_op_buf_full() || db->num_insns >= db->max_insns) { 135 db->is_jmp = DISAS_TOO_MANY; 136 break; 137 } 138 } 139 140 /* Emit code to exit the TB, as indicated by db->is_jmp. */ 141 ops->tb_stop(db, cpu); 142 gen_tb_end(db->tb, db->num_insns - bp_insn); 143 144 if (plugin_enabled) { 145 plugin_gen_tb_end(cpu); 146 } 147 148 /* The disas_log hook may use these values rather than recompute. */ 149 tb->size = db->pc_next - db->pc_first; 150 tb->icount = db->num_insns; 151 152 #ifdef DEBUG_DISAS 153 if (qemu_loglevel_mask(CPU_LOG_TB_IN_ASM) 154 && qemu_log_in_addr_range(db->pc_first)) { 155 FILE *logfile = qemu_log_lock(); 156 qemu_log("----------------\n"); 157 ops->disas_log(db, cpu); 158 qemu_log("\n"); 159 qemu_log_unlock(logfile); 160 } 161 #endif 162 } 163