LXR qemu/accel/tcg/translator.c

   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.  */
  26void 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
  34void 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