Merge remote-tracking branch 'remotes/rth/tags/pull-tcg-20200717' into staging

Fix vector min/max fallback expansion
Fix singlestep from exception and interrupt

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# gpg:                using RSA key 7A481E78868B4DB6A85A05C064DF38E8AF7E215F
# gpg:                issuer "richard.henderson@linaro.org"
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* remotes/rth/tags/pull-tcg-20200717:
  tcg/cpu-exec: precise single-stepping after an interrupt
  tcg/cpu-exec: precise single-stepping after an exception
  tcg: Save/restore vecop_list around minmax fallback

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 20 insertions, 1 deletions

diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index d95c4848a4..66d38f9d85 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -504,6 +504,17 @@ static inline bool cpu_handle_exception(CPUState *cpu, int *ret)
             cc->do_interrupt(cpu);
             qemu_mutex_unlock_iothread();
             cpu->exception_index = -1;
+
+            if (unlikely(cpu->singlestep_enabled)) {
+                /*
+                 * After processing the exception, ensure an EXCP_DEBUG is
+                 * raised when single-stepping so that GDB doesn't miss the
+                 * next instruction.
+                 */
+                *ret = EXCP_DEBUG;
+                cpu_handle_debug_exception(cpu);
+                return true;
+            }
         } else if (!replay_has_interrupt()) {
             /* give a chance to iothread in replay mode */
             *ret = EXCP_INTERRUPT;
@@ -577,7 +588,13 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
         else {
             if (cc->cpu_exec_interrupt(cpu, interrupt_request)) {
                 replay_interrupt();
-                cpu->exception_index = -1;
+                /*
+                 * After processing the interrupt, ensure an EXCP_DEBUG is
+                 * raised when single-stepping so that GDB doesn't miss the
+                 * next instruction.
+                 */
+                cpu->exception_index =
+                    (cpu->singlestep_enabled ? EXCP_DEBUG : -1);
                 *last_tb = NULL;
             }
             /* The target hook may have updated the 'cpu->interrupt_request';
diff --git a/tcg/tcg-op-vec.c b/tcg/tcg-op-vec.c
index f784517d84..ed6fb55fe1 100644
--- a/tcg/tcg-op-vec.c
+++ b/tcg/tcg-op-vec.c
@@ -657,7 +657,9 @@ static void do_minmax(unsigned vece, TCGv_vec r, TCGv_vec a,
                       TCGv_vec b, TCGOpcode opc, TCGCond cond)
 {
     if (!do_op3(vece, r, a, b, opc)) {
+        const TCGOpcode *hold_list = tcg_swap_vecop_list(NULL);
         tcg_gen_cmpsel_vec(cond, vece, r, a, b, a, b);
+        tcg_swap_vecop_list(hold_list);
     }
 }