PowerPC disassembly of odd sized sections

Message ID 20200320020655.GF4583@bubble.grove.modra.org
State New
Headers show
Series
  • PowerPC disassembly of odd sized sections
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Commit Message

Stefan Schulze Frielinghaus via Binutils March 20, 2020, 2:06 a.m.
We shouldn't really decode a 2-byte left-over at the end of a section
as if the section contains two more bytes of zeros.  Not that it
matters very much, but this patch tidies the corner case.

	* ppc-dis.c (print_insn_powerpc): Only clear needed bytes of
	partially filled buffer.  Prevent lookup of 4-byte insns when
	only VLE 2-byte insns are possible due to section size.  Print
	".word" rather than ".long" for 2-byte leftovers.


-- 
Alan Modra
Australia Development Lab, IBM

Patch

diff --git a/opcodes/ppc-dis.c b/opcodes/ppc-dis.c
index a735fbb5a9..b437fafa37 100644
--- a/opcodes/ppc-dis.c
+++ b/opcodes/ppc-dis.c
@@ -750,8 +750,9 @@  print_insn_powerpc (bfd_vma memaddr,
   if (status != 0 && (dialect & PPC_OPCODE_VLE) != 0)
     {
       /* Clear buffer so unused bytes will not have garbage in them.  */
-      buffer[0] = buffer[1] = buffer[2] = buffer[3] = 0;
+      buffer[2] = buffer[3] = 0;
       status = (*info->read_memory_func) (memaddr, buffer, 2, info);
+      insn_length = 2;
     }
 
   if (status != 0)
@@ -801,12 +802,15 @@  print_insn_powerpc (bfd_vma memaddr,
 	  insn_length = 2;
 	}
     }
-  if (opcode == NULL && (dialect & PPC_OPCODE_SPE2) != 0)
-    opcode = lookup_spe2 (insn);
-  if (opcode == NULL)
-    opcode = lookup_powerpc (insn, dialect & ~PPC_OPCODE_ANY);
-  if (opcode == NULL && (dialect & PPC_OPCODE_ANY) != 0)
-    opcode = lookup_powerpc (insn, dialect);
+  if (opcode == NULL && insn_length == 4)
+    {
+      if ((dialect & PPC_OPCODE_SPE2) != 0)
+	opcode = lookup_spe2 (insn);
+      if (opcode == NULL)
+	opcode = lookup_powerpc (insn, dialect & ~PPC_OPCODE_ANY);
+      if (opcode == NULL && (dialect & PPC_OPCODE_ANY) != 0)
+	opcode = lookup_powerpc (insn, dialect);
+    }
 
   if (opcode != NULL)
     {
@@ -918,9 +922,13 @@  print_insn_powerpc (bfd_vma memaddr,
     }
 
   /* We could not find a match.  */
-  (*info->fprintf_func) (info->stream, ".long 0x%" PRIx64, insn);
-
-  return 4;
+  if (insn_length == 4)
+    (*info->fprintf_func) (info->stream, ".long 0x%x",
+			   (unsigned int) insn);
+  else
+    (*info->fprintf_func) (info->stream, ".word 0x%x",
+			   (unsigned int) insn >> 16);
+  return insn_length;
 }
 
 const disasm_options_and_args_t *