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 max_insns; 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 max_insns = tb_cflags(db->tb) & CF_COUNT_MASK; 49 if (max_insns == 0) { 50 max_insns = CF_COUNT_MASK; 51 } 52 if (max_insns > TCG_MAX_INSNS) { 53 max_insns = TCG_MAX_INSNS; 54 } 55 if (db->singlestep_enabled || singlestep) { 56 max_insns = 1; 57 } 58 59 max_insns = ops->init_disas_context(db, cpu, max_insns); 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 (unlikely(!QTAILQ_EMPTY(&cpu->breakpoints))) { 77 CPUBreakpoint *bp; 78 QTAILQ_FOREACH(bp, &cpu->breakpoints, entry) { 79 if (bp->pc == db->pc_next) { 80 if (ops->breakpoint_check(db, cpu, bp)) { 81 break; 82 } 83 } 84 } 85 /* The breakpoint_check hook may use DISAS_TOO_MANY to indicate 86 that only one more instruction is to be executed. Otherwise 87 it should use DISAS_NORETURN when generating an exception, 88 but may use a DISAS_TARGET_* value for Something Else. */ 89 if (db->is_jmp > DISAS_TOO_MANY) { 90 break; 91 } 92 } 93 94 /* Disassemble one instruction. The translate_insn hook should 95 update db->pc_next and db->is_jmp to indicate what should be 96 done next -- either exiting this loop or locate the start of 97 the next instruction. */ 98 if (db->num_insns == max_insns && (tb_cflags(db->tb) & CF_LAST_IO)) { 99 /* Accept I/O on the last instruction. */ 100 gen_io_start(); 101 ops->translate_insn(db, cpu); 102 gen_io_end(); 103 } else { 104 ops->translate_insn(db, cpu); 105 } 106 107 /* Stop translation if translate_insn so indicated. */ 108 if (db->is_jmp != DISAS_NEXT) { 109 break; 110 } 111 112 /* Stop translation if the output buffer is full, 113 or we have executed all of the allowed instructions. */ 114 if (tcg_op_buf_full() || db->num_insns >= max_insns) { 115 db->is_jmp = DISAS_TOO_MANY; 116 break; 117 } 118 } 119 120 /* Emit code to exit the TB, as indicated by db->is_jmp. */ 121 ops->tb_stop(db, cpu); 122 gen_tb_end(db->tb, db->num_insns); 123 124 /* The disas_log hook may use these values rather than recompute. */ 125 db->tb->size = db->pc_next - db->pc_first; 126 db->tb->icount = db->num_insns; 127 128 #ifdef DEBUG_DISAS 129 if (qemu_loglevel_mask(CPU_LOG_TB_IN_ASM) 130 && qemu_log_in_addr_range(db->pc_first)) { 131 qemu_log_lock(); 132 qemu_log("----------------\n"); 133 ops->disas_log(db, cpu); 134 qemu_log("\n"); 135 qemu_log_unlock(); 136 } 137 #endif 138 } 139