accel/tcg: Move most of gen-icount.h into translator.c

The only usage of gen_tb_start and gen_tb_end are here.
Move the static icount_start_insn variable into a local
within translator_loop.  Simplify the two subroutines
by passing in the existing local cflags variable.

Leave only the declaration of gen_io_start in gen-icount.h.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 81 insertions, 2 deletions

diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c
index 6120ef2..b0d0015 100644
--- a/accel/tcg/translator.c
+++ b/accel/tcg/translator.c
@@ -18,6 +18,84 @@
 #include "exec/plugin-gen.h"
 #include "exec/replay-core.h"
 
+
+void gen_io_start(void)
+{
+    tcg_gen_st_i32(tcg_constant_i32(1), cpu_env,
+                   offsetof(ArchCPU, parent_obj.can_do_io) -
+                   offsetof(ArchCPU, env));
+}
+
+static TCGOp *gen_tb_start(uint32_t cflags)
+{
+    TCGv_i32 count = tcg_temp_new_i32();
+    TCGOp *icount_start_insn = NULL;
+
+    tcg_gen_ld_i32(count, cpu_env,
+                   offsetof(ArchCPU, neg.icount_decr.u32) -
+                   offsetof(ArchCPU, env));
+
+    if (cflags & CF_USE_ICOUNT) {
+        /*
+         * We emit a sub with a dummy immediate argument. Keep the insn index
+         * of the sub so that we later (when we know the actual insn count)
+         * can update the argument with the actual insn count.
+         */
+        tcg_gen_sub_i32(count, count, tcg_constant_i32(0));
+        icount_start_insn = tcg_last_op();
+    }
+
+    /*
+     * Emit the check against icount_decr.u32 to see if we should exit
+     * unless we suppress the check with CF_NOIRQ. If we are using
+     * icount and have suppressed interruption the higher level code
+     * should have ensured we don't run more instructions than the
+     * budget.
+     */
+    if (cflags & CF_NOIRQ) {
+        tcg_ctx->exitreq_label = NULL;
+    } else {
+        tcg_ctx->exitreq_label = gen_new_label();
+        tcg_gen_brcondi_i32(TCG_COND_LT, count, 0, tcg_ctx->exitreq_label);
+    }
+
+    if (cflags & CF_USE_ICOUNT) {
+        tcg_gen_st16_i32(count, cpu_env,
+                         offsetof(ArchCPU, neg.icount_decr.u16.low) -
+                         offsetof(ArchCPU, env));
+        /*
+         * cpu->can_do_io is cleared automatically here at the beginning of
+         * each translation block.  The cost is minimal and only paid for
+         * -icount, plus it would be very easy to forget doing it in the
+         * translator. Doing it here means we don't need a gen_io_end() to
+         * go with gen_io_start().
+         */
+        tcg_gen_st_i32(tcg_constant_i32(0), cpu_env,
+                       offsetof(ArchCPU, parent_obj.can_do_io) -
+                       offsetof(ArchCPU, env));
+    }
+
+    return icount_start_insn;
+}
+
+static void gen_tb_end(const TranslationBlock *tb, uint32_t cflags,
+                       TCGOp *icount_start_insn, int num_insns)
+{
+    if (cflags & CF_USE_ICOUNT) {
+        /*
+         * Update the num_insn immediate parameter now that we know
+         * the actual insn count.
+         */
+        tcg_set_insn_param(icount_start_insn, 2,
+                           tcgv_i32_arg(tcg_constant_i32(num_insns)));
+    }
+
+    if (tcg_ctx->exitreq_label) {
+        gen_set_label(tcg_ctx->exitreq_label);
+        tcg_gen_exit_tb(tb, TB_EXIT_REQUESTED);
+    }
+}
+
 bool translator_use_goto_tb(DisasContextBase *db, target_ulong dest)
 {
     /* Suppress goto_tb if requested. */
@@ -34,6 +112,7 @@ void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns,
                      const TranslatorOps *ops, DisasContextBase *db)
 {
     uint32_t cflags = tb_cflags(tb);
+    TCGOp *icount_start_insn;
     bool plugin_enabled;
 
     /* Initialize DisasContext */
@@ -55,7 +134,7 @@ void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns,
     tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
 
     /* Start translating.  */
-    gen_tb_start(db->tb);
+    icount_start_insn = gen_tb_start(cflags);
     ops->tb_start(db, cpu);
     tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
 
@@ -112,7 +191,7 @@ void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns,
 
     /* 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);
+    gen_tb_end(tb, cflags, icount_start_insn, db->num_insns);
 
     if (plugin_enabled) {
         plugin_gen_tb_end(cpu);