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