[Qemu-devel] [PATCH] target-arm: Fix garbage collection of temporaries in Neon emulation.

[Christophe Lyon <christophe.lyon@st.com>]

Fix garbage collection of temporaries in Neon emulation.


Signed-off-by: Christophe Lyon <christophe.lyon@st.com>
---
 target-arm/translate.c |   22 +++++++++++++++++-----
 1 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/target-arm/translate.c b/target-arm/translate.c
index 57664bc..363351e 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -4176,6 +4176,18 @@ static inline void gen_neon_mull(TCGv_i64 dest,
TCGv a, TCGv b, int size, int u)
         break;
     default: abort();
     }
+
+    /* gen_helper_neon_mull_[su]{8|16} do not free their parameters.
+       Don't forget to clean them now.  */
+    switch ((size << 1) | u) {
+    case 0:
+    case 1:
+    case 2:
+    case 3:
+      dead_tmp(a);
+      dead_tmp(b);
+      break;
+    }
 }

 /* Translate a NEON data processing instruction.  Return nonzero if the
@@ -4840,7 +4852,7 @@ static int disas_neon_data_insn(CPUState * env,
DisasContext *s, uint32_t insn)
                 if (size == 3) {
                     tcg_temp_free_i64(tmp64);
                 } else {
-                    dead_tmp(tmp2);
+                    tcg_temp_free_i32(tmp2);
                 }
             } else if (op == 10) {
                 /* VSHLL */
@@ -5076,8 +5088,6 @@ static int disas_neon_data_insn(CPUState * env,
DisasContext *s, uint32_t insn)
                     case 8: case 9: case 10: case 11: case 12: case 13:
                         /* VMLAL, VQDMLAL, VMLSL, VQDMLSL, VMULL,
VQDMULL */
                         gen_neon_mull(cpu_V0, tmp, tmp2, size, u);
-                        dead_tmp(tmp2);
-                        dead_tmp(tmp);
                         break;
                     case 14: /* Polynomial VMULL */
                         cpu_abort(env, "Polynomial VMULL not implemented");
@@ -5235,9 +5245,12 @@ static int disas_neon_data_insn(CPUState * env,
DisasContext *s, uint32_t insn)
                             tmp = neon_load_reg(rn, 0);
                         } else {
                             tmp = tmp3;
+			    /* tmp2 has been discarded in
+			       gen_neon_mull during pass 0, we need to
+			       recreate it.  */
+			    tmp2 = neon_get_scalar(size, rm);
                         }
                         gen_neon_mull(cpu_V0, tmp, tmp2, size, u);
-                        dead_tmp(tmp);
                         if (op == 6 || op == 7) {
                             gen_neon_negl(cpu_V0, size);
                         }
@@ -5264,7 +5277,6 @@ static int disas_neon_data_insn(CPUState * env,
DisasContext *s, uint32_t insn)
                         neon_store_reg64(cpu_V0, rd + pass);
                     }

-                    dead_tmp(tmp2);

                     break;
                 default: /* 14 and 15 are RESERVED */
-- 
1.7.2.3