PR24851, gas/testsuite/gas/epiphany/badrelax.s failure with MALLOC_PERTURB_=1

	PR 24851
	* config/tc-epiphany.c (md_estimate_size_before_relax): Clear
	extra opcode bytes when changing from a 2-byte to a 4-byte insn.

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 91180f2..68c4002 100644 (file)
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,9 @@
+2019-08-12  Alan Modra  <amodra@gmail.com>
+
+       PR 24851
+       * config/tc-epiphany.c (md_estimate_size_before_relax): Clear
+       extra opcode bytes when changing from a 2-byte to a 4-byte insn.
+
 2019-08-09  Jan Beulich  <jbeulich@suse.com>
 
        * testsuite/gas/i386/ilp32/x86-64-simd-intel.d,

diff --git a/gas/config/tc-epiphany.c b/gas/config/tc-epiphany.c
index 3117918..5429fa9 100644 (file)
--- a/gas/config/tc-epiphany.c
+++ b/gas/config/tc-epiphany.c
@@ -727,6 +727,8 @@ md_estimate_size_before_relax (fragS *fragP, segT segment)
         handling to md_convert_frag.  */
 
       EPIPHANY_RELAX_TYPES subtype;
+      const CGEN_INSN *insn;
+      int i;
       /* We haven't relaxed this at all, so the relaxation type may be
         completely wrong.  Set the subtype correctly.  */
       epiphany_relax_frag (segment, fragP, 0);
@@ -753,26 +755,29 @@ md_estimate_size_before_relax (fragS *fragP, segT segment)
 
       fragP->fr_subtype = subtype;
 
-      {
-       const CGEN_INSN *insn;
-       int i;
-
-       /* Update the recorded insn.  */
+      /* Update the recorded insn.  */
+      for (i = 0, insn = fragP->fr_cgen.insn; i < 4; i++, insn++)
+       {
+         if (strcmp (CGEN_INSN_MNEMONIC (insn),
+                     CGEN_INSN_MNEMONIC (fragP->fr_cgen.insn)) == 0
+             && CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXED))
+           break;
+       }
 
-       for (i = 0, insn = fragP->fr_cgen.insn; i < 4; i++, insn++)
-         {
-           if ((strcmp (CGEN_INSN_MNEMONIC (insn),
-                        CGEN_INSN_MNEMONIC (fragP->fr_cgen.insn))
-                == 0)
-               && CGEN_INSN_ATTR_VALUE (insn, CGEN_INSN_RELAXED))
-             break;
-         }
+      if (i == 4)
+       abort ();
 
-       if (i == 4)
-         abort ();
+      /* When changing from a 2-byte to 4-byte insn, don't leave
+        opcode bytes uninitialised.  */
+      if (CGEN_INSN_BITSIZE (fragP->fr_cgen.insn) < CGEN_INSN_BITSIZE (insn))
+       {
+         gas_assert (CGEN_INSN_BITSIZE (fragP->fr_cgen.insn) == 16);
+         gas_assert (CGEN_INSN_BITSIZE (insn) == 32);
+         fragP->fr_opcode[2] = 0;
+         fragP->fr_opcode[3] = 0;
+       }
 
-       fragP->fr_cgen.insn = insn;
-      }
+      fragP->fr_cgen.insn = insn;
     }
 
   return md_relax_table[fragP->fr_subtype].rlx_length;