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 "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.  */
  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
  34bool translator_use_goto_tb(DisasContextBase *db, target_ulong dest)
  35{
  36    /* Suppress goto_tb if requested. */
  37    if (tb_cflags(db->tb) & CF_NO_GOTO_TB) {
  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
  45void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
  46                     CPUState *cpu, TranslationBlock *tb, int max_insns)
  47{
  48    uint32_t cflags = tb_cflags(tb);
  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 = cflags & CF_SINGLE_STEP;
  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, cflags & CF_MEMI_ONLY);
  72
  73    while (true) {
  74        db->num_insns++;
  75        ops->insn_start(db, cpu);
  76        tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
  77
  78        if (plugin_enabled) {
  79            plugin_gen_insn_start(cpu, db);
  80        }
  81
  82        /* Disassemble one instruction.  The translate_insn hook should
  83           update db->pc_next and db->is_jmp to indicate what should be
  84           done next -- either exiting this loop or locate the start of
  85           the next instruction.  */
  86        if (db->num_insns == db->max_insns && (cflags & CF_LAST_IO)) {
  87            /* Accept I/O on the last instruction.  */
  88            gen_io_start();
  89            ops->translate_insn(db, cpu);
  90        } else {
  91            /* we should only see CF_MEMI_ONLY for io_recompile */
  92            tcg_debug_assert(!(cflags & CF_MEMI_ONLY));
  93            ops->translate_insn(db, cpu);
  94        }
  95
  96        /* Stop translation if translate_insn so indicated.  */
  97        if (db->is_jmp != DISAS_NEXT) {
  98            break;
  99        }
 100
 101        /*
 102         * We can't instrument after instructions that change control
 103         * flow although this only really affects post-load operations.
 104         */
 105        if (plugin_enabled) {
 106            plugin_gen_insn_end();
 107        }
 108
 109        /* Stop translation if the output buffer is full,
 110           or we have executed all of the allowed instructions.  */
 111        if (tcg_op_buf_full() || db->num_insns >= db->max_insns) {
 112            db->is_jmp = DISAS_TOO_MANY;
 113            break;
 114        }
 115    }
 116
 117    /* Emit code to exit the TB, as indicated by db->is_jmp.  */
 118    ops->tb_stop(db, cpu);
 119    gen_tb_end(db->tb, db->num_insns);
 120
 121    if (plugin_enabled) {
 122        plugin_gen_tb_end(cpu);
 123    }
 124
 125    /* The disas_log hook may use these values rather than recompute.  */
 126    tb->size = db->pc_next - db->pc_first;
 127    tb->icount = db->num_insns;
 128
 129#ifdef DEBUG_DISAS
 130    if (qemu_loglevel_mask(CPU_LOG_TB_IN_ASM)
 131        && qemu_log_in_addr_range(db->pc_first)) {
 132        FILE *logfile = qemu_log_lock();
 133        qemu_log("----------------\n");
 134        ops->disas_log(db, cpu);
 135        qemu_log("\n");
 136        qemu_log_unlock(logfile);
 137    }
 138#endif
 139}
 140