[Qemu-devel] [PATCH v13 03/26] target: [tcg] Add generic translation framework

["Lluís Vilanova" <vilanova@ac.upc.edu>]

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
---
 accel/tcg/Makefile.objs   |    1 
 accel/tcg/translator.c    |  141 +++++++++++++++++++++++++++++++++++++++++++++
 include/exec/translator.h |   94 ++++++++++++++++++++++++++++++
 3 files changed, 236 insertions(+)
 create mode 100644 accel/tcg/translator.c

diff --git a/accel/tcg/Makefile.objs b/accel/tcg/Makefile.objs
index 70cd474c01..22642e6f75 100644
--- a/accel/tcg/Makefile.objs
+++ b/accel/tcg/Makefile.objs
@@ -1,3 +1,4 @@
 obj-$(CONFIG_SOFTMMU) += tcg-all.o
 obj-$(CONFIG_SOFTMMU) += cputlb.o
 obj-y += cpu-exec.o cpu-exec-common.o translate-all.o
+obj-y += translator.o
diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c
new file mode 100644
index 0000000000..630edfd353
--- /dev/null
+++ b/accel/tcg/translator.c
@@ -0,0 +1,141 @@
+/*
+ * 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"
+
+
+static inline void translate_block_tcg_check(const DisasContextBase *db)
+{
+    if (tcg_check_temp_count()) {
+        error_report("warning: TCG temporary leaks before "TARGET_FMT_lx,
+                     db->pc_next);
+    }
+}
+
+void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
+                     CPUState *cpu, TranslationBlock *tb)
+{
+    int max_insns;
+
+    /* 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;
+    ops->init_disas_context(db, cpu);
+    /* should never be set by this hook */
+    assert(db->is_jmp == DISAS_NEXT);
+
+    /* Reset the temp count so that we can identify leaks */
+    tcg_clear_temp_count();
+
+    /* Instruction counting */
+    max_insns = db->tb->cflags & CF_COUNT_MASK;
+    if (max_insns == 0) {
+        max_insns = CF_COUNT_MASK;
+    }
+    if (max_insns > TCG_MAX_INSNS) {
+        max_insns = TCG_MAX_INSNS;
+    }
+    if (db->singlestep_enabled || singlestep) {
+        max_insns = 1;
+    }
+
+    /* Start translating */
+    gen_tb_start(db->tb);
+    ops->tb_start(db, cpu, &max_insns);
+    /* should never be set by this hook */
+    assert(db->is_jmp == DISAS_NEXT);
+
+    while (true) {
+        db->num_insns++;
+        ops->insn_start(db, cpu);
+
+        /* Early exit before breakpoint checks */
+        if (unlikely(db->is_jmp != DISAS_NEXT)) {
+            break;
+        }
+
+        /* Pass breakpoint hits to target for further processing */
+        if (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)) {
+                        break;
+                    }
+                }
+            }
+
+            if (db->is_jmp == DISAS_NORETURN) {
+                break;
+            }
+        }
+
+        /* Accept I/O on last instruction */
+        if (db->num_insns == max_insns && (db->tb->cflags & CF_LAST_IO)) {
+            gen_io_start();
+        }
+
+        /* Disassemble one instruction */
+        db->pc_next = ops->translate_insn(db, cpu);
+
+        /**************************************************/
+        /* Conditions to stop translation                 */
+        /**************************************************/
+
+        /* Target-specific conditions set by disassembly */
+        if (db->is_jmp != DISAS_NEXT) {
+            break;
+        }
+
+        /* Too many instructions */
+        if (tcg_op_buf_full() || db->num_insns >= max_insns) {
+            db->is_jmp = DISAS_TOO_MANY;
+            break;
+        }
+
+        translate_block_tcg_check(db);
+    }
+
+    if ((db->tb->cflags & CF_LAST_IO)) {
+        gen_io_end();
+    }
+
+    ops->tb_stop(db, cpu);
+
+    gen_tb_end(db->tb, db->num_insns);
+
+    translate_block_tcg_check(db);
+
+#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
+
+    db->tb->size = db->pc_next - db->pc_first;
+    db->tb->icount = db->num_insns;
+}
diff --git a/include/exec/translator.h b/include/exec/translator.h
index b51b8f8a4e..3806e01d8b 100644
--- a/include/exec/translator.h
+++ b/include/exec/translator.h
@@ -10,6 +10,19 @@
 #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.
@@ -37,4 +50,85 @@ typedef enum DisasJumpType {
     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 a DisasContext struct (DisasContextBase has
+ *                      already been initialized).
+ * @tb_start: Start translating a new TB. Can override the maximum number of
+ *            instructions to translate, as calculated by the generic code in
+ *            translator_loop().
+ * @insn_start: Start translating a new instruction.
+ * @breakpoint_check: Check if a breakpoint did hit, in which case no more
+ *                    breakpoints are checked. When called, the breakpoint has
+ *                    already been checked to match the PC, but targets can
+ *                    decide the breakpoint missed the address (e.g., due to
+ *                    conditions encoded in their flags).
+ * @translate_insn: Disassemble one instruction and return the PC for the next
+ *                  one. Can set db->is_jmp to DISAS_TARGET or above to stop
+ *                  translation.
+ * @tb_stop: Stop translating a TB.
+ * @disas_log: Print instruction disassembly to log.
+ *
+ * Target-specific operations for the generic translator loop.
+ *
+ * The following hooks can set DisasContextBase::is_jmp to stop the translation
+ * loop:
+ *
+ * - insn_start(), translate_insn()
+ *   -> is_jmp != DISAS_NEXT
+ *
+ * - insn_start(), breakpoint_check(), translate_insn()
+ *   -> is_jmp == DISAS_NORETURN
+ */
+typedef struct TranslatorOps {
+    void (*init_disas_context)(DisasContextBase *db, CPUState *cpu);
+    void (*tb_start)(DisasContextBase *db, CPUState *cpu, int *max_insns);
+    void (*insn_start)(DisasContextBase *db, CPUState *cpu);
+    bool (*breakpoint_check)(DisasContextBase *db, CPUState *cpu,
+                             const CPUBreakpoint *bp);
+    target_ulong (*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 set by #TranslatorOps::insn_start.
+ * - When set by #TranslatorOps::translate_insn.
+ * - 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);
+
 #endif  /* EXEC__TRANSLATOR_H */