include/exec/translator.h

   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 #ifndef EXEC__TRANSLATOR_H
  11 #define EXEC__TRANSLATOR_H
  12
  13 /*
  14  * Include this header from a target-specific file, and add a
  15  *
  16  *     DisasContextBase base;
  17  *
  18  * member in your target-specific DisasContext.
  19  */
  20
  21
  22 #include "exec/exec-all.h"
  23 #include "tcg/tcg.h"
  24
  25
  26 /**
  27  * DisasJumpType:
  28  * @DISAS_NEXT: Next instruction in program order.
  29  * @DISAS_TOO_MANY: Too many instructions translated.
  30  * @DISAS_NORETURN: Following code is dead.
  31  * @DISAS_TARGET_*: Start of target-specific conditions.
  32  *
  33  * What instruction to disassemble next.
  34  */
  35 typedef enum DisasJumpType {
  36     DISAS_NEXT,
  37     DISAS_TOO_MANY,
  38     DISAS_NORETURN,
  39     DISAS_TARGET_0,
  40     DISAS_TARGET_1,
  41     DISAS_TARGET_2,
  42     DISAS_TARGET_3,
  43     DISAS_TARGET_4,
  44     DISAS_TARGET_5,
  45     DISAS_TARGET_6,
  46     DISAS_TARGET_7,
  47     DISAS_TARGET_8,
  48     DISAS_TARGET_9,
  49     DISAS_TARGET_10,
  50     DISAS_TARGET_11,
  51 } DisasJumpType;
  52
  53 /**
  54  * DisasContextBase:
  55  * @tb: Translation block for this disassembly.
  56  * @pc_first: Address of first guest instruction in this TB.
  57  * @pc_next: Address of next guest instruction in this TB (current during
  58  *           disassembly).
  59  * @is_jmp: What instruction to disassemble next.
  60  * @num_insns: Number of translated instructions (including current).
  61  * @singlestep_enabled: "Hardware" single stepping enabled.
  62  *
  63  * Architecture-agnostic disassembly context.
  64  */
  65 typedef struct DisasContextBase {
  66     TranslationBlock *tb;
  67     target_ulong pc_first;
  68     target_ulong pc_next;
  69     DisasJumpType is_jmp;
  70     unsigned int num_insns;
  71     bool singlestep_enabled;
  72 } DisasContextBase;
  73
  74 /**
  75  * TranslatorOps:
  76  * @init_disas_context:
  77  *      Initialize the target-specific portions of DisasContext struct.
  78  *      The generic DisasContextBase has already been initialized.
  79  *      Return max_insns, modified as necessary by db->tb->flags.
  80  *
  81  * @tb_start:
  82  *      Emit any code required before the start of the main loop,
  83  *      after the generic gen_tb_start().
  84  *
  85  * @insn_start:
  86  *      Emit the tcg_gen_insn_start opcode.
  87  *
  88  * @breakpoint_check:
  89  *      When called, the breakpoint has already been checked to match the PC,
  90  *      but the target may decide the breakpoint missed the address
  91  *      (e.g., due to conditions encoded in their flags).  Return true to
  92  *      indicate that the breakpoint did hit, in which case no more breakpoints
  93  *      are checked.  If the breakpoint did hit, emit any code required to
  94  *      signal the exception, and set db->is_jmp as necessary to terminate
  95  *      the main loop.
  96  *
  97  * @translate_insn:
  98  *      Disassemble one instruction and set db->pc_next for the start
  99  *      of the following instruction.  Set db->is_jmp as necessary to
 100  *      terminate the main loop.
 101  *
 102  * @tb_stop:
 103  *      Emit any opcodes required to exit the TB, based on db->is_jmp.
 104  *
 105  * @disas_log:
 106  *      Print instruction disassembly to log.
 107  */
 108 typedef struct TranslatorOps {
 109     int (*init_disas_context)(DisasContextBase *db, CPUState *cpu,
 110                               int max_insns);
 111     void (*tb_start)(DisasContextBase *db, CPUState *cpu);
 112     void (*insn_start)(DisasContextBase *db, CPUState *cpu);
 113     bool (*breakpoint_check)(DisasContextBase *db, CPUState *cpu,
 114                              const CPUBreakpoint *bp);
 115     void (*translate_insn)(DisasContextBase *db, CPUState *cpu);
 116     void (*tb_stop)(DisasContextBase *db, CPUState *cpu);
 117     void (*disas_log)(const DisasContextBase *db, CPUState *cpu);
 118 } TranslatorOps;
 119
 120 /**
 121  * translator_loop:
 122  * @ops: Target-specific operations.
 123  * @db: Disassembly context.
 124  * @cpu: Target vCPU.
 125  * @tb: Translation block.
 126  *
 127  * Generic translator loop.
 128  *
 129  * Translation will stop in the following cases (in order):
 130  * - When is_jmp set by #TranslatorOps::breakpoint_check.
 131  *   - set to DISAS_TOO_MANY exits after translating one more insn
 132  *   - set to any other value than DISAS_NEXT exits immediately.
 133  * - When is_jmp set by #TranslatorOps::translate_insn.
 134  *   - set to any value other than DISAS_NEXT exits immediately.
 135  * - When the TCG operation buffer is full.
 136  * - When single-stepping is enabled (system-wide or on the current vCPU).
 137  * - When too many instructions have been translated.
 138  */
 139 void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
 140                      CPUState *cpu, TranslationBlock *tb);
 141
 142 void translator_loop_temp_check(DisasContextBase *db);
 143
 144 #endif  /* EXEC__TRANSLATOR_H */