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#include "exec/plugin-gen.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, int max_insns)
  36{
  37    int bp_insn = 0;
  38    bool plugin_enabled;
  39
  40    /* Initialize DisasContext */
  41    db->tb = tb;
  42    db->pc_first = tb->pc;
  43    db->pc_next = db->pc_first;
  44    db->is_jmp = DISAS_NEXT;
  45    db->num_insns = 0;
  46    db->max_insns = max_insns;
  47    db->singlestep_enabled = cpu->singlestep_enabled;
  48
  49    ops->init_disas_context(db, cpu);
  50    tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
  51
  52    /* Reset the temp count so that we can identify leaks */
  53    tcg_clear_temp_count();
  54
  55    /* Start translating.  */
  56    gen_tb_start(db->tb);
  57    ops->tb_start(db, cpu);
  58    tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
  59
  60    plugin_enabled = plugin_gen_tb_start(cpu, tb);
  61
  62    while (true) {
  63        db->num_insns++;
  64        ops->insn_start(db, cpu);
  65        tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
  66
  67        if (plugin_enabled) {
  68            plugin_gen_insn_start(cpu, db);
  69        }
  70
  71        /* Pass breakpoint hits to target for further processing */
  72        if (!db->singlestep_enabled
  73            && unlikely(!QTAILQ_EMPTY(&cpu->breakpoints))) {
  74            CPUBreakpoint *bp;
  75            QTAILQ_FOREACH(bp, &cpu->breakpoints, entry) {
  76                if (bp->pc == db->pc_next) {
  77                    if (ops->breakpoint_check(db, cpu, bp)) {
  78                        bp_insn = 1;
  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        } else {
 102            ops->translate_insn(db, cpu);
 103        }
 104
 105        /* Stop translation if translate_insn so indicated.  */
 106        if (db->is_jmp != DISAS_NEXT) {
 107            break;
 108        }
 109
 110        /*
 111         * We can't instrument after instructions that change control
 112         * flow although this only really affects post-load operations.
 113         */
 114        if (plugin_enabled) {
 115            plugin_gen_insn_end();
 116        }
 117
 118        /* Stop translation if the output buffer is full,
 119           or we have executed all of the allowed instructions.  */
 120        if (tcg_op_buf_full() || db->num_insns >= db->max_insns) {
 121            db->is_jmp = DISAS_TOO_MANY;
 122            break;
 123        }
 124    }
 125
 126    /* Emit code to exit the TB, as indicated by db->is_jmp.  */
 127    ops->tb_stop(db, cpu);
 128    gen_tb_end(db->tb, db->num_insns - bp_insn);
 129
 130    if (plugin_enabled) {
 131        plugin_gen_tb_end(cpu);
 132    }
 133
 134    /* The disas_log hook may use these values rather than recompute.  */
 135    db->tb->size = db->pc_next - db->pc_first;
 136    db->tb->icount = db->num_insns;
 137
 138#ifdef DEBUG_DISAS
 139    if (qemu_loglevel_mask(CPU_LOG_TB_IN_ASM)
 140        && qemu_log_in_addr_range(db->pc_first)) {
 141        qemu_log_lock();
 142        qemu_log("----------------\n");
 143        ops->disas_log(db, cpu);
 144        qemu_log("\n");
 145        qemu_log_unlock();
 146    }
 147#endif
 148}
 149