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 "cpu.h"
13#include "tcg/tcg.h"
14#include "tcg/tcg-op.h"
15#include "exec/exec-all.h"
16#include "exec/gen-icount.h"
17#include "exec/log.h"
18#include "exec/translator.h"
19
20/* Pairs with tcg_clear_temp_count.
21 To be called by #TranslatorOps.{translate_insn,tb_stop} if
22 (1) the target is sufficiently clean to support reporting,
23 (2) as and when all temporaries are known to be consumed.
24 For most targets, (2) is at the end of translate_insn. */
25void translator_loop_temp_check(DisasContextBase *db)
26{
27 if (tcg_check_temp_count()) {
28 qemu_log("warning: TCG temporary leaks before "
29 TARGET_FMT_lx "\n", db->pc_next);
30 }
31}
32
33void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
34 CPUState *cpu, TranslationBlock *tb, int max_insns)
35{
36 int bp_insn = 0;
37
38 /* Initialize DisasContext */
39 db->tb = tb;
40 db->pc_first = tb->pc;
41 db->pc_next = db->pc_first;
42 db->is_jmp = DISAS_NEXT;
43 db->num_insns = 0;
44 db->max_insns = max_insns;
45 db->singlestep_enabled = cpu->singlestep_enabled;
46
47 ops->init_disas_context(db, cpu);
48 tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */
49
50 /* Reset the temp count so that we can identify leaks */
51 tcg_clear_temp_count();
52
53 /* Start translating. */
54 gen_tb_start(db->tb);
55 ops->tb_start(db, cpu);
56 tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */
57
58 while (true) {
59 db->num_insns++;
60 ops->insn_start(db, cpu);
61 tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */
62
63 /* Pass breakpoint hits to target for further processing */
64 if (!db->singlestep_enabled
65 && unlikely(!QTAILQ_EMPTY(&cpu->breakpoints))) {
66 CPUBreakpoint *bp;
67 QTAILQ_FOREACH(bp, &cpu->breakpoints, entry) {
68 if (bp->pc == db->pc_next) {
69 if (ops->breakpoint_check(db, cpu, bp)) {
70 bp_insn = 1;
71 break;
72 }
73 }
74 }
75 /* The breakpoint_check hook may use DISAS_TOO_MANY to indicate
76 that only one more instruction is to be executed. Otherwise
77 it should use DISAS_NORETURN when generating an exception,
78 but may use a DISAS_TARGET_* value for Something Else. */
79 if (db->is_jmp > DISAS_TOO_MANY) {
80 break;
81 }
82 }
83
84 /* Disassemble one instruction. The translate_insn hook should
85 update db->pc_next and db->is_jmp to indicate what should be
86 done next -- either exiting this loop or locate the start of
87 the next instruction. */
88 if (db->num_insns == db->max_insns
89 && (tb_cflags(db->tb) & CF_LAST_IO)) {
90 /* Accept I/O on the last instruction. */
91 gen_io_start();
92 ops->translate_insn(db, cpu);
93 } else {
94 ops->translate_insn(db, cpu);
95 }
96
97 /* Stop translation if translate_insn so indicated. */
98 if (db->is_jmp != DISAS_NEXT) {
99 break;
100 }
101
102 /* Stop translation if the output buffer is full,
103 or we have executed all of the allowed instructions. */
104 if (tcg_op_buf_full() || db->num_insns >= db->max_insns) {
105 db->is_jmp = DISAS_TOO_MANY;
106 break;
107 }
108 }
109
110 /* Emit code to exit the TB, as indicated by db->is_jmp. */
111 ops->tb_stop(db, cpu);
112 gen_tb_end(db->tb, db->num_insns - bp_insn);
113
114 /* The disas_log hook may use these values rather than recompute. */
115 db->tb->size = db->pc_next - db->pc_first;
116 db->tb->icount = db->num_insns;
117
118#ifdef DEBUG_DISAS
119 if (qemu_loglevel_mask(CPU_LOG_TB_IN_ASM)
120 && qemu_log_in_addr_range(db->pc_first)) {
121 qemu_log_lock();
122 qemu_log("----------------\n");
123 ops->disas_log(db, cpu);
124 qemu_log("\n");
125 qemu_log_unlock();
126 }
127#endif
128}
129