i#2974 add trace support for AArch64, part 1: cbr inversion for AArch…

…64 (#5042)

This patch added implementation for instr_invert_cbr() on AArch64 as well as
changing the implementation of instr_set_predicate by clearing the predicate
bits before setting them.

Issues: #2974, #1569

core/ir/aarch64/instr.c

@@ -300,7 +300,20 @@ instr_is_undefined(instr_t *instr)
 void
 instr_invert_cbr(instr_t *instr)
 {
-    ASSERT_NOT_IMPLEMENTED(false); /* FIXME i#1569 */
+    int opc = instr_get_opcode(instr);
+    dr_pred_type_t pred = instr_get_predicate(instr);
+    CLIENT_ASSERT(instr_is_cbr(instr), "instr_invert_cbr: instr not a cbr");
+    if (opc == OP_cbnz) {
+        instr_set_opcode(instr, OP_cbz);
+    } else if (opc == OP_cbz) {
+        instr_set_opcode(instr, OP_cbnz);
+    } else if (opc == OP_tbnz) {
+        instr_set_opcode(instr, OP_tbz);
+    } else if (opc == OP_tbz) {
+        instr_set_opcode(instr, OP_tbnz);
+    } else {
+        instr_set_predicate(instr, instr_invert_predicate(pred));
+    }
 }
 
 bool

core/ir/instr_shared.c

@@ -751,7 +751,8 @@ instr_get_predicate(instr_t *instr)
 instr_t *
 instr_set_predicate(instr_t *instr, dr_pred_type_t pred)
 {
-    instr->prefixes |= ((pred << PREFIX_PRED_BITPOS) & PREFIX_PRED_MASK);
+    instr->prefixes = ((instr->prefixes & ~PREFIX_PRED_MASK) |
+                       ((pred << PREFIX_PRED_BITPOS) & PREFIX_PRED_MASK));
     return instr;
 }