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/*
* 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.
*/
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qemu/error-report.h"
#include "cpu.h"
#include "tcg/tcg.h"
#include "tcg/tcg-op.h"
#include "exec/exec-all.h"
#include "exec/gen-icount.h"
#include "exec/log.h"
#include "exec/translator.h"
/* Pairs with tcg_clear_temp_count.
To be called by #TranslatorOps.{translate_insn,tb_stop} if
(1) the target is sufficiently clean to support reporting,
(2) as and when all temporaries are known to be consumed.
For most targets, (2) is at the end of translate_insn. */
void translator_loop_temp_check(DisasContextBase *db)
{
if (tcg_check_temp_count()) {
qemu_log("warning: TCG temporary leaks before "
TARGET_FMT_lx "\n", db->pc_next);
}
}
void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
CPUState *cpu, TranslationBlock *tb)
{
int bp_insn = 0;
/* Initialize DisasContext */
db->tb = tb;
db->pc_first = tb->pc;
db->pc_next = db->pc_first;
db->is_jmp = DISAS_NEXT;
db->num_insns = 0;
db->singlestep_enabled = cpu->singlestep_enabled;
/* Instruction counting */
db->max_insns = tb_cflags(db->tb) & CF_COUNT_MASK;
if (db->max_insns == 0) {
db->max_insns = CF_COUNT_MASK;
}
if (db->max_insns > TCG_MAX_INSNS) {
db->max_insns = TCG_MAX_INSNS;
}
if (db->singlestep_enabled || singlestep) {
db->max_insns = 1;
}
ops->init_disas_context(db, cpu);
tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */
/* Reset the temp count so that we can identify leaks */
tcg_clear_temp_count();
/* Start translating. */
gen_tb_start(db->tb);
ops->tb_start(db, cpu);
tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */
while (true) {
db->num_insns++;
ops->insn_start(db, cpu);
tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */
/* Pass breakpoint hits to target for further processing */
if (!db->singlestep_enabled
&& unlikely(!QTAILQ_EMPTY(&cpu->breakpoints))) {
CPUBreakpoint *bp;
QTAILQ_FOREACH(bp, &cpu->breakpoints, entry) {
if (bp->pc == db->pc_next) {
if (ops->breakpoint_check(db, cpu, bp)) {
bp_insn = 1;
break;
}
}
}
/* The breakpoint_check hook may use DISAS_TOO_MANY to indicate
that only one more instruction is to be executed. Otherwise
it should use DISAS_NORETURN when generating an exception,
but may use a DISAS_TARGET_* value for Something Else. */
if (db->is_jmp > DISAS_TOO_MANY) {
break;
}
}
/* Disassemble one instruction. The translate_insn hook should
update db->pc_next and db->is_jmp to indicate what should be
done next -- either exiting this loop or locate the start of
the next instruction. */
if (db->num_insns == db->max_insns
&& (tb_cflags(db->tb) & CF_LAST_IO)) {
/* Accept I/O on the last instruction. */
gen_io_start();
ops->translate_insn(db, cpu);
gen_io_end();
} else {
ops->translate_insn(db, cpu);
}
/* Stop translation if translate_insn so indicated. */
if (db->is_jmp != DISAS_NEXT) {
break;
}
/* Stop translation if the output buffer is full,
or we have executed all of the allowed instructions. */
if (tcg_op_buf_full() || db->num_insns >= db->max_insns) {
db->is_jmp = DISAS_TOO_MANY;
break;
}
}
/* Emit code to exit the TB, as indicated by db->is_jmp. */
ops->tb_stop(db, cpu);
gen_tb_end(db->tb, db->num_insns - bp_insn);
/* The disas_log hook may use these values rather than recompute. */
db->tb->size = db->pc_next - db->pc_first;
db->tb->icount = db->num_insns;
#ifdef DEBUG_DISAS
if (qemu_loglevel_mask(CPU_LOG_TB_IN_ASM)
&& qemu_log_in_addr_range(db->pc_first)) {
qemu_log_lock();
qemu_log("----------------\n");
ops->disas_log(db, cpu);
qemu_log("\n");
qemu_log_unlock();
}
#endif
}
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