include/exec/translator.h

/*
 * Generic intermediate code generation.
 *
 * Copyright (C) 2016-2017 Lluís Vilanova <vilanova@ac.upc.edu>
 *
 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 * See the COPYING file in the top-level directory.
 */

#ifndef EXEC__TRANSLATOR_H
#define EXEC__TRANSLATOR_H

/*
 * Include this header from a target-specific file, and add a
 *
 *     DisasContextBase base;
 *
 * member in your target-specific DisasContext.
 */


#include "exec/exec-all.h"
#include "tcg/tcg.h"


/**
 * DisasJumpType:
 * @DISAS_NEXT: Next instruction in program order.
 * @DISAS_TOO_MANY: Too many instructions translated.
 * @DISAS_NORETURN: Following code is dead.
 * @DISAS_TARGET_*: Start of target-specific conditions.
 *
 * What instruction to disassemble next.
 */
typedef enum DisasJumpType {
    DISAS_NEXT,
    DISAS_TOO_MANY,
    DISAS_NORETURN,
    DISAS_TARGET_0,
    DISAS_TARGET_1,
    DISAS_TARGET_2,
    DISAS_TARGET_3,
    DISAS_TARGET_4,
    DISAS_TARGET_5,
    DISAS_TARGET_6,
    DISAS_TARGET_7,
    DISAS_TARGET_8,
    DISAS_TARGET_9,
    DISAS_TARGET_10,
    DISAS_TARGET_11,
} DisasJumpType;

/**
 * DisasContextBase:
 * @tb: Translation block for this disassembly.
 * @pc_first: Address of first guest instruction in this TB.
 * @pc_next: Address of next guest instruction in this TB (current during
 *           disassembly).
 * @is_jmp: What instruction to disassemble next.
 * @num_insns: Number of translated instructions (including current).
 * @singlestep_enabled: "Hardware" single stepping enabled.
 *
 * Architecture-agnostic disassembly context.
 */
typedef struct DisasContextBase {
    TranslationBlock *tb;
    target_ulong pc_first;
    target_ulong pc_next;
    DisasJumpType is_jmp;
    unsigned int num_insns;
    bool singlestep_enabled;
} DisasContextBase;

/**
 * TranslatorOps:
 * @init_disas_context:
 *      Initialize the target-specific portions of DisasContext struct.
 *      The generic DisasContextBase has already been initialized.
 *      Return max_insns, modified as necessary by db->tb->flags.
 *
 * @tb_start:
 *      Emit any code required before the start of the main loop,
 *      after the generic gen_tb_start().
 *
 * @insn_start:
 *      Emit the tcg_gen_insn_start opcode.
 *
 * @breakpoint_check:
 *      When called, the breakpoint has already been checked to match the PC,
 *      but the target may decide the breakpoint missed the address
 *      (e.g., due to conditions encoded in their flags).  Return true to
 *      indicate that the breakpoint did hit, in which case no more breakpoints
 *      are checked.  If the breakpoint did hit, emit any code required to
 *      signal the exception, and set db->is_jmp as necessary to terminate
 *      the main loop.
 *
 * @translate_insn:
 *      Disassemble one instruction and set db->pc_next for the start
 *      of the following instruction.  Set db->is_jmp as necessary to
 *      terminate the main loop.
 *
 * @tb_stop:
 *      Emit any opcodes required to exit the TB, based on db->is_jmp.
 *
 * @disas_log:
 *      Print instruction disassembly to log.
 */
typedef struct TranslatorOps {
    int (*init_disas_context)(DisasContextBase *db, CPUState *cpu,
                              int max_insns);
    void (*tb_start)(DisasContextBase *db, CPUState *cpu);
    void (*insn_start)(DisasContextBase *db, CPUState *cpu);
    bool (*breakpoint_check)(DisasContextBase *db, CPUState *cpu,
                             const CPUBreakpoint *bp);
    void (*translate_insn)(DisasContextBase *db, CPUState *cpu);
    void (*tb_stop)(DisasContextBase *db, CPUState *cpu);
    void (*disas_log)(const DisasContextBase *db, CPUState *cpu);
} TranslatorOps;

/**
 * translator_loop:
 * @ops: Target-specific operations.
 * @db: Disassembly context.
 * @cpu: Target vCPU.
 * @tb: Translation block.
 *
 * Generic translator loop.
 *
 * Translation will stop in the following cases (in order):
 * - When is_jmp set by #TranslatorOps::breakpoint_check.
 *   - set to DISAS_TOO_MANY exits after translating one more insn
 *   - set to any other value than DISAS_NEXT exits immediately.
 * - When is_jmp set by #TranslatorOps::translate_insn.
 *   - set to any value other than DISAS_NEXT exits immediately.
 * - When the TCG operation buffer is full.
 * - When single-stepping is enabled (system-wide or on the current vCPU).
 * - When too many instructions have been translated.
 */
void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
                     CPUState *cpu, TranslationBlock *tb);

void translator_loop_temp_check(DisasContextBase *db);

#endif  /* EXEC__TRANSLATOR_H */