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 int bp_insn = 0; 38 39 /* Initialize DisasContext */ 40 db->tb = tb; 41 db->pc_first = tb->pc; 42 db->pc_next = db->pc_first; 43 db->is_jmp = DISAS_NEXT; 44 db->num_insns = 0; 45 db->singlestep_enabled = cpu->singlestep_enabled; 46 47 /* Instruction counting */ 48 db->max_insns = tb_cflags(db->tb) & CF_COUNT_MASK; 49 if (db->max_insns == 0) { 50 db->max_insns = CF_COUNT_MASK; 51 } 52 if (db->max_insns > TCG_MAX_INSNS) { 53 db->max_insns = TCG_MAX_INSNS; 54 } 55 if (db->singlestep_enabled || singlestep) { 56 db->max_insns = 1; 57 } 58 59 ops->init_disas_context(db, cpu); 60 tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */ 61 62 /* Reset the temp count so that we can identify leaks */ 63 tcg_clear_temp_count(); 64 65 /* Start translating. */ 66 gen_tb_start(db->tb); 67 ops->tb_start(db, cpu); 68 tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */ 69 70 while (true) { 71 db->num_insns++; 72 ops->insn_start(db, cpu); 73 tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */ 74 75 /* Pass breakpoint hits to target for further processing */ 76 if (!db->singlestep_enabled 77 && unlikely(!QTAILQ_EMPTY(&cpu->breakpoints))) { 78 CPUBreakpoint *bp; 79 QTAILQ_FOREACH(bp, &cpu->breakpoints, entry) { 80 if (bp->pc == db->pc_next) { 81 if (ops->breakpoint_check(db, cpu, bp)) { 82 bp_insn = 1; 83 break; 84 } 85 } 86 } 87 /* The breakpoint_check hook may use DISAS_TOO_MANY to indicate 88 that only one more instruction is to be executed. Otherwise 89 it should use DISAS_NORETURN when generating an exception, 90 but may use a DISAS_TARGET_* value for Something Else. */ 91 if (db->is_jmp > DISAS_TOO_MANY) { 92 break; 93 } 94 } 95 96 /* Disassemble one instruction. The translate_insn hook should 97 update db->pc_next and db->is_jmp to indicate what should be 98 done next -- either exiting this loop or locate the start of 99 the next instruction. */ 100 if (db->num_insns == db->max_insns 101 && (tb_cflags(db->tb) & CF_LAST_IO)) { 102 /* Accept I/O on the last instruction. */ 103 gen_io_start(); 104 ops->translate_insn(db, cpu); 105 gen_io_end(); 106 } else { 107 ops->translate_insn(db, cpu); 108 } 109 110 /* Stop translation if translate_insn so indicated. */ 111 if (db->is_jmp != DISAS_NEXT) { 112 break; 113 } 114 115 /* Stop translation if the output buffer is full, 116 or we have executed all of the allowed instructions. */ 117 if (tcg_op_buf_full() || db->num_insns >= db->max_insns) { 118 db->is_jmp = DISAS_TOO_MANY; 119 break; 120 } 121 } 122 123 /* Emit code to exit the TB, as indicated by db->is_jmp. */ 124 ops->tb_stop(db, cpu); 125 gen_tb_end(db->tb, db->num_insns - bp_insn); 126 127 /* The disas_log hook may use these values rather than recompute. */ 128 db->tb->size = db->pc_next - db->pc_first; 129 db->tb->icount = db->num_insns; 130 131 #ifdef DEBUG_DISAS 132 if (qemu_loglevel_mask(CPU_LOG_TB_IN_ASM) 133 && qemu_log_in_addr_range(db->pc_first)) { 134 qemu_log_lock(); 135 qemu_log("----------------\n"); 136 ops->disas_log(db, cpu); 137 qemu_log("\n"); 138 qemu_log_unlock(); 139 } 140 #endif 141 } 142