gdb/

[deliverable/binutils-gdb.git] / gas / expr.c

diff --git a/gas/expr.c b/gas/expr.c
index 500f93840ba59d86fb622e1916106bbf9fa5790d..c4b2b756bae5b94b4266bd8c0e405f63ca5fb2b0 100644 (file)
--- a/gas/expr.c
+++ b/gas/expr.c
@@ -90,6 +90,7 @@ make_expr_symbol (expressionS *expressionP)
       zero.X_op = O_constant;
       zero.X_add_number = 0;
       zero.X_unsigned = 0;
+      zero.X_extrabit = 0;
       clean_up_expression (&zero);
       expressionP = &zero;
     }
@@ -161,6 +162,7 @@ expr_build_uconstant (offsetT value)
   e.X_op = O_constant;
   e.X_add_number = value;
   e.X_unsigned = 1;
+  e.X_extrabit = 0;
   return make_expr_symbol (&e);
 }
 
@@ -732,6 +734,7 @@ operand (expressionS *expressionP, enum expr_mode mode)
      something like ``.quad 0x80000000'' is not sign extended even
      though it appears negative if valueT is 32 bits.  */
   expressionP->X_unsigned = 1;
+  expressionP->X_extrabit = 0;
 
   /* Digits, assume it is a bignum.  */
 
@@ -1026,6 +1029,8 @@ operand (expressionS *expressionP, enum expr_mode mode)
                   This is compatible with other people's
                   assemblers.  Sigh.  */
                expressionP->X_unsigned = 0;
+               if (expressionP->X_add_number)
+                 expressionP->X_extrabit ^= 1;
              }
            else if (c == '~' || c == '"')
              expressionP->X_add_number = ~ expressionP->X_add_number;
@@ -1078,6 +1083,7 @@ operand (expressionS *expressionP, enum expr_mode mode)
                expressionP->X_add_number = i >= expressionP->X_add_number;
                expressionP->X_op = O_constant;
                expressionP->X_unsigned = 1;
+               expressionP->X_extrabit = 0;
              }
          }
        else if (expressionP->X_op != O_illegal
@@ -1717,6 +1723,42 @@ operatorf (int *num_chars)
   /* NOTREACHED  */
 }
 
+/* Implement "word-size + 1 bit" addition for
+   {resultP->X_extrabit:resultP->X_add_number} + {rhs_highbit:amount}.  This
+   is used so that the full range of unsigned word values and the full range of
+   signed word values can be represented in an O_constant expression, which is
+   useful e.g. for .sleb128 directives.  */
+
+void
+add_to_result (expressionS *resultP, offsetT amount, int rhs_highbit)
+{
+  valueT ures = resultP->X_add_number;
+  valueT uamount = amount;
+
+  resultP->X_add_number += amount;
+
+  resultP->X_extrabit ^= rhs_highbit;
+
+  if (ures + uamount < ures)
+    resultP->X_extrabit ^= 1;
+}
+
+/* Similarly, for subtraction.  */
+
+void
+subtract_from_result (expressionS *resultP, offsetT amount, int rhs_highbit)
+{
+  valueT ures = resultP->X_add_number;
+  valueT uamount = amount;
+
+  resultP->X_add_number -= amount;
+
+  resultP->X_extrabit ^= rhs_highbit;
+
+  if (ures < uamount)
+    resultP->X_extrabit ^= 1;
+}
+
 /* Parse an expression.  */
 
 segT
@@ -1832,7 +1874,7 @@ expr (int rankarg,                /* Larger # is higher rank.  */
          && (md_register_arithmetic || resultP->X_op != O_register))
        {
          /* X + constant.  */
-         resultP->X_add_number += right.X_add_number;
+         add_to_result (resultP, right.X_add_number, right.X_extrabit);
        }
       /* This case comes up in PIC code.  */
       else if (op_left == O_subtract
@@ -1850,10 +1892,11 @@ expr (int rankarg,              /* Larger # is higher rank.  */
                                       symbol_get_frag (right.X_add_symbol),
                                       &frag_off))
        {
-         resultP->X_add_number -= right.X_add_number;
-         resultP->X_add_number -= frag_off / OCTETS_PER_BYTE;
-         resultP->X_add_number += (S_GET_VALUE (resultP->X_add_symbol)
-                                   - S_GET_VALUE (right.X_add_symbol));
+         offsetT symval_diff = S_GET_VALUE (resultP->X_add_symbol)
+                               - S_GET_VALUE (right.X_add_symbol);
+         subtract_from_result (resultP, right.X_add_number, right.X_extrabit);
+         subtract_from_result (resultP, frag_off / OCTETS_PER_BYTE, 0);
+         add_to_result (resultP, symval_diff, symval_diff < 0);
          resultP->X_op = O_constant;
          resultP->X_add_symbol = 0;
        }
@@ -1861,7 +1904,7 @@ expr (int rankarg,                /* Larger # is higher rank.  */
               && (md_register_arithmetic || resultP->X_op != O_register))
        {
          /* X - constant.  */
-         resultP->X_add_number -= right.X_add_number;
+         subtract_from_result (resultP, right.X_add_number, right.X_extrabit);
        }
       else if (op_left == O_add && resultP->X_op == O_constant
               && (md_register_arithmetic || right.X_op != O_register))
@@ -1870,7 +1913,7 @@ expr (int rankarg,                /* Larger # is higher rank.  */
          resultP->X_op = right.X_op;
          resultP->X_add_symbol = right.X_add_symbol;
          resultP->X_op_symbol = right.X_op_symbol;
-         resultP->X_add_number += right.X_add_number;
+         add_to_result (resultP, right.X_add_number, right.X_extrabit);
          retval = rightseg;
        }
       else if (resultP->X_op == O_constant && right.X_op == O_constant)
@@ -1910,7 +1953,9 @@ expr (int rankarg,                /* Larger # is higher rank.  */
              /* Constant + constant (O_add) is handled by the
                 previous if statement for constant + X, so is omitted
                 here.  */
-           case O_subtract:            resultP->X_add_number -= v; break;
+           case O_subtract:
+             subtract_from_result (resultP, v, 0);
+             break;
            case O_eq:
              resultP->X_add_number =
                resultP->X_add_number == v ? ~ (offsetT) 0 : 0;
@@ -1954,10 +1999,11 @@ expr (int rankarg,              /* Larger # is higher rank.  */
          resultP->X_op = op_left;
          resultP->X_op_symbol = right.X_add_symbol;
          if (op_left == O_add)
-           resultP->X_add_number += right.X_add_number;
+           add_to_result (resultP, right.X_add_number, right.X_extrabit);
          else if (op_left == O_subtract)
            {
-             resultP->X_add_number -= right.X_add_number;
+             subtract_from_result (resultP, right.X_add_number,
+                                   right.X_extrabit);
              if (retval == rightseg
                  && SEG_NORMAL (retval)
                  && !S_FORCE_RELOC (resultP->X_add_symbol, 0)
@@ -1977,6 +2023,7 @@ expr (int rankarg,                /* Larger # is higher rank.  */
          resultP->X_op = op_left;
          resultP->X_add_number = 0;
          resultP->X_unsigned = 1;
+         resultP->X_extrabit = 0;
        }
 
       if (retval != rightseg)