tcg: Add generic translation framework

Reviewed-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Message-Id: <150002073981.22386.9870422422367410100.stgit@frigg.lan>
[rth: Moved max_insns adjustment from tb_start to init_disas_context.
Removed pc_next return from translate_insn.
Removed tcg_check_temp_count from generic loop.
Moved gen_io_end to exactly match gen_io_start.
Use qemu_log instead of error_report for temporary leaks.
Moved TB size/icount assignments before disas_log.]
Signed-off-by: Richard Henderson <rth@twiddle.net>

1 files changed, 104 insertions, 0 deletions

diff --git a/include/exec/translator.h b/include/exec/translator.h
index b51b8f8a4e..e2dc2a04ae 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 +50,95 @@ 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 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 */