[Qemu-devel] [PATCH 1/2] target-sparc: Fix -singlestep.

[Richard Henderson <rth@twiddle.net>]

Single-stepping was not properly updating npc, resulting in some
instructions being executed twice.  In addition, we were emitting
dead code at the end of the TB.

Fix both by teaching gen_goto_tb to avoid goto_tb for single-step
and removing the special-case code in gen_intermediate_code_internal.

Signed-off-by: Richard Henderson <rth@twiddle.net>
---
 target-sparc/translate.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/target-sparc/translate.c b/target-sparc/translate.c
index b54c520..5162b87 100644
--- a/target-sparc/translate.c
+++ b/target-sparc/translate.c
@@ -81,6 +81,7 @@ typedef struct DisasContext {
     int address_mask_32bit;
     uint32_t cc_op;  /* current CC operation */
     struct TranslationBlock *tb;
+    CPUState *env;
     sparc_def_t *def;
 } DisasContext;
 
@@ -234,7 +235,8 @@ static inline void gen_goto_tb(DisasContext *s, int tb_num,
 
     tb = s->tb;
     if ((pc & TARGET_PAGE_MASK) == (tb->pc & TARGET_PAGE_MASK) &&
-        (npc & TARGET_PAGE_MASK) == (tb->pc & TARGET_PAGE_MASK))  {
+        (npc & TARGET_PAGE_MASK) == (tb->pc & TARGET_PAGE_MASK) &&
+        !(s->env->singlestep_enabled || singlestep))  {
         /* jump to same page: we can use a direct jump */
         tcg_gen_goto_tb(tb_num);
         tcg_gen_movi_tl(cpu_pc, pc);
@@ -4680,6 +4682,7 @@ static inline void gen_intermediate_code_internal(TranslationBlock * tb,
 
     memset(dc, 0, sizeof(DisasContext));
     dc->tb = tb;
+    dc->env = env;
     pc_start = tb->pc;
     dc->pc = pc_start;
     last_pc = dc->pc;
@@ -4755,8 +4758,6 @@ static inline void gen_intermediate_code_internal(TranslationBlock * tb,
         /* if single step mode, we generate only one instruction and
            generate an exception */
         if (env->singlestep_enabled || singlestep) {
-            tcg_gen_movi_tl(cpu_pc, dc->pc);
-            tcg_gen_exit_tb(0);
             break;
         }
     } while ((gen_opc_ptr < gen_opc_end) &&
-- 
1.6.6.1