8b86d6d258
In order to handle TB's that translate to too much code, we need to place the control of the length of the translation in the hands of the code gen master loop. Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
131 lines
4.2 KiB
C
131 lines
4.2 KiB
C
/*
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* Generic intermediate code generation.
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*
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* Copyright (C) 2016-2017 Lluís Vilanova <vilanova@ac.upc.edu>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*/
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#include "qemu/osdep.h"
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#include "qemu-common.h"
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#include "qemu/error-report.h"
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#include "cpu.h"
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#include "tcg/tcg.h"
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#include "tcg/tcg-op.h"
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#include "exec/exec-all.h"
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#include "exec/gen-icount.h"
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#include "exec/log.h"
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#include "exec/translator.h"
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/* Pairs with tcg_clear_temp_count.
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To be called by #TranslatorOps.{translate_insn,tb_stop} if
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(1) the target is sufficiently clean to support reporting,
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(2) as and when all temporaries are known to be consumed.
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For most targets, (2) is at the end of translate_insn. */
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void translator_loop_temp_check(DisasContextBase *db)
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{
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if (tcg_check_temp_count()) {
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qemu_log("warning: TCG temporary leaks before "
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TARGET_FMT_lx "\n", db->pc_next);
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}
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}
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void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
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CPUState *cpu, TranslationBlock *tb, int max_insns)
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{
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int bp_insn = 0;
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/* Initialize DisasContext */
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db->tb = tb;
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db->pc_first = tb->pc;
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db->pc_next = db->pc_first;
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db->is_jmp = DISAS_NEXT;
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db->num_insns = 0;
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db->max_insns = max_insns;
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db->singlestep_enabled = cpu->singlestep_enabled;
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ops->init_disas_context(db, cpu);
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tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */
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/* Reset the temp count so that we can identify leaks */
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tcg_clear_temp_count();
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/* Start translating. */
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gen_tb_start(db->tb);
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ops->tb_start(db, cpu);
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tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */
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while (true) {
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db->num_insns++;
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ops->insn_start(db, cpu);
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tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */
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/* Pass breakpoint hits to target for further processing */
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if (!db->singlestep_enabled
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&& unlikely(!QTAILQ_EMPTY(&cpu->breakpoints))) {
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CPUBreakpoint *bp;
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QTAILQ_FOREACH(bp, &cpu->breakpoints, entry) {
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if (bp->pc == db->pc_next) {
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if (ops->breakpoint_check(db, cpu, bp)) {
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bp_insn = 1;
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break;
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}
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}
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}
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/* The breakpoint_check hook may use DISAS_TOO_MANY to indicate
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that only one more instruction is to be executed. Otherwise
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it should use DISAS_NORETURN when generating an exception,
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but may use a DISAS_TARGET_* value for Something Else. */
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if (db->is_jmp > DISAS_TOO_MANY) {
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break;
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}
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}
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/* Disassemble one instruction. The translate_insn hook should
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update db->pc_next and db->is_jmp to indicate what should be
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done next -- either exiting this loop or locate the start of
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the next instruction. */
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if (db->num_insns == db->max_insns
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&& (tb_cflags(db->tb) & CF_LAST_IO)) {
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/* Accept I/O on the last instruction. */
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gen_io_start();
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ops->translate_insn(db, cpu);
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gen_io_end();
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} else {
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ops->translate_insn(db, cpu);
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}
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/* Stop translation if translate_insn so indicated. */
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if (db->is_jmp != DISAS_NEXT) {
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break;
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}
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/* Stop translation if the output buffer is full,
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or we have executed all of the allowed instructions. */
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if (tcg_op_buf_full() || db->num_insns >= db->max_insns) {
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db->is_jmp = DISAS_TOO_MANY;
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break;
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}
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}
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/* Emit code to exit the TB, as indicated by db->is_jmp. */
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ops->tb_stop(db, cpu);
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gen_tb_end(db->tb, db->num_insns - bp_insn);
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/* The disas_log hook may use these values rather than recompute. */
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db->tb->size = db->pc_next - db->pc_first;
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db->tb->icount = db->num_insns;
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#ifdef DEBUG_DISAS
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if (qemu_loglevel_mask(CPU_LOG_TB_IN_ASM)
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&& qemu_log_in_addr_range(db->pc_first)) {
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qemu_log_lock();
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qemu_log("----------------\n");
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ops->disas_log(db, cpu);
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qemu_log("\n");
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qemu_log_unlock();
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}
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#endif
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}
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