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.  */
  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 bool 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
  45 void 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 }