Add inclusive range support for Rust

This is version 2 of the patch to add inclusive range support for
Rust.  I believe it addresses all review comments.

Rust recently stabilized the inclusive range feature:

    https://github.com/rust-lang/rust/issues/28237

An inclusive range is an expression like "..= EXPR" or "EXPR ..=
EXPR".  It is like an ordinary range, except the upper bound is
inclusive, not exclusive.

This patch adds support for this feature to gdb.

Regression tested on x86-64 Fedora 27.

2018-04-27  Tom Tromey  <tom@tromey.com>

	PR rust/22545:
	* rust-lang.c (rust_inclusive_range_type_p): New function.
	(rust_range): Handle inclusive ranges.
	(rust_compute_range): Likewise.
	* rust-exp.y (struct rust_op) <inclusive>: New field.
	(DOTDOTEQ): New constant.
	(range_expr): Add "..=" productions.
	(operator_tokens): Add "..=" token.
	(ast_range): Add "inclusive" parameter.
	(convert_ast_to_expression) <case OP_RANGE>: Handle inclusive
	ranges.
	* parse.c (operator_length_standard) <case OP_RANGE>: Handle new
	bounds values.
	* expression.h (enum range_type) <NONE_BOUND_DEFAULT_EXCLUSIVE,
	LOW_BOUND_DEFAULT_EXCLUSIVE>: New constants.
	Update comments.
	* expprint.c (print_subexp_standard): Handle new bounds values.
	(dump_subexp_body_standard): Likewise.

2018-04-27  Tom Tromey  <tom@tromey.com>

	PR rust/22545:
	* gdb.rust/simple.exp: Add inclusive range tests.

8 files changed, 117 insertions, 23 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f6cb82b..2b9e554 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,26 @@
 2018-04-27  Tom Tromey  <tom@tromey.com>
 
+	PR rust/22545:
+	* rust-lang.c (rust_inclusive_range_type_p): New function.
+	(rust_range): Handle inclusive ranges.
+	(rust_compute_range): Likewise.
+	* rust-exp.y (struct rust_op) <inclusive>: New field.
+	(DOTDOTEQ): New constant.
+	(range_expr): Add "..=" productions.
+	(operator_tokens): Add "..=" token.
+	(ast_range): Add "inclusive" parameter.
+	(convert_ast_to_expression) <case OP_RANGE>: Handle inclusive
+	ranges.
+	* parse.c (operator_length_standard) <case OP_RANGE>: Handle new
+	bounds values.
+	* expression.h (enum range_type) <NONE_BOUND_DEFAULT_EXCLUSIVE,
+	LOW_BOUND_DEFAULT_EXCLUSIVE>: New constants.
+	Update comments.
+	* expprint.c (print_subexp_standard): Handle new bounds values.
+	(dump_subexp_body_standard): Likewise.
+
+2018-04-27  Tom Tromey  <tom@tromey.com>
+
 	* configure: Rebuild.
 	* warning.m4 (AM_GDB_WARNINGS): Add -Wsuggest-override.
 	* dwarf2loc.c (class dwarf_evaluate_loc_desc): Use "override", not
diff --git a/gdb/expprint.c b/gdb/expprint.c
index c906904..047ec11 100644
--- a/gdb/expprint.c
+++ b/gdb/expprint.c
@@ -578,9 +578,13 @@ print_subexp_standard (struct expression *exp, int *pos,
 	  longest_to_int (exp->elts[pc + 1].longconst);
 	*pos += 2;
 
+	if (range_type == NONE_BOUND_DEFAULT_EXCLUSIVE
+	    || range_type == LOW_BOUND_DEFAULT_EXCLUSIVE)
+	  fputs_filtered ("EXCLUSIVE_", stream);
 	fputs_filtered ("RANGE(", stream);
 	if (range_type == HIGH_BOUND_DEFAULT
-	    || range_type == NONE_BOUND_DEFAULT)
+	    || range_type == NONE_BOUND_DEFAULT
+	    || range_type == NONE_BOUND_DEFAULT_EXCLUSIVE)
 	  print_subexp (exp, pos, stream, PREC_ABOVE_COMMA);
 	fputs_filtered ("..", stream);
 	if (range_type == LOW_BOUND_DEFAULT
@@ -1099,12 +1103,18 @@ dump_subexp_body_standard (struct expression *exp,
 	  case LOW_BOUND_DEFAULT:
 	    fputs_filtered ("Range '..EXP'", stream);
 	    break;
+	  case LOW_BOUND_DEFAULT_EXCLUSIVE:
+	    fputs_filtered ("ExclusiveRange '..EXP'", stream);
+	    break;
 	  case HIGH_BOUND_DEFAULT:
 	    fputs_filtered ("Range 'EXP..'", stream);
 	    break;
 	  case NONE_BOUND_DEFAULT:
 	    fputs_filtered ("Range 'EXP..EXP'", stream);
 	    break;
+	  case NONE_BOUND_DEFAULT_EXCLUSIVE:
+	    fputs_filtered ("ExclusiveRange 'EXP..EXP'", stream);
+	    break;
 	  default:
 	    fputs_filtered ("Invalid Range!", stream);
 	    break;
diff --git a/gdb/expression.h b/gdb/expression.h
index 7abd7f7..9f26bb8 100644
--- a/gdb/expression.h
+++ b/gdb/expression.h
@@ -150,15 +150,26 @@ extern void dump_prefix_expression (struct expression *, struct ui_file *);
 
 /* In an OP_RANGE expression, either bound could be empty, indicating
    that its value is by default that of the corresponding bound of the
-   array or string.  So we have four sorts of subrange.  This
-   enumeration type is to identify this.  */
-   
+   array or string.  Also, the upper end of the range can be exclusive
+   or inclusive.  So we have six sorts of subrange.  This enumeration
+   type is to identify this.  */
+
 enum range_type
-  {
-    BOTH_BOUND_DEFAULT,		/* "(:)"  */
-    LOW_BOUND_DEFAULT,		/* "(:high)"  */
-    HIGH_BOUND_DEFAULT,		/* "(low:)"  */
-    NONE_BOUND_DEFAULT		/* "(low:high)"  */
-  };
+{
+  /* Neither the low nor the high bound was given -- so this refers to
+     the entire available range.  */
+  BOTH_BOUND_DEFAULT,
+  /* The low bound was not given and the high bound is inclusive.  */
+  LOW_BOUND_DEFAULT,
+  /* The high bound was not given and the low bound in inclusive.  */
+  HIGH_BOUND_DEFAULT,
+  /* Both bounds were given and both are inclusive.  */
+  NONE_BOUND_DEFAULT,
+  /* The low bound was not given and the high bound is exclusive.  */
+  NONE_BOUND_DEFAULT_EXCLUSIVE,
+  /* Both bounds were given.  The low bound is inclusive and the high
+     bound is exclusive.  */
+  LOW_BOUND_DEFAULT_EXCLUSIVE,
+};
 
 #endif /* !defined (EXPRESSION_H) */
diff --git a/gdb/parse.c b/gdb/parse.c
index 1d53b5a..193abe8 100644
--- a/gdb/parse.c
+++ b/gdb/parse.c
@@ -995,6 +995,7 @@ operator_length_standard (const struct expression *expr, int endpos,
       switch (range_type)
 	{
 	case LOW_BOUND_DEFAULT:
+	case LOW_BOUND_DEFAULT_EXCLUSIVE:
 	case HIGH_BOUND_DEFAULT:
 	  args = 1;
 	  break;
@@ -1002,6 +1003,7 @@ operator_length_standard (const struct expression *expr, int endpos,
 	  args = 0;
 	  break;
 	case NONE_BOUND_DEFAULT:
+	case NONE_BOUND_DEFAULT_EXCLUSIVE:
 	  args = 2;
 	  break;
 	}
diff --git a/gdb/rust-exp.y b/gdb/rust-exp.y
index b661a80..56aa689 100644
--- a/gdb/rust-exp.y
+++ b/gdb/rust-exp.y
@@ -111,7 +111,8 @@ static const struct rust_op *ast_string (struct stoken str);
 static const struct rust_op *ast_struct (const struct rust_op *name,
 					 rust_set_vector *fields);
 static const struct rust_op *ast_range (const struct rust_op *lhs,
-					const struct rust_op *rhs);
+					const struct rust_op *rhs,
+					bool inclusive);
 static const struct rust_op *ast_array_type (const struct rust_op *lhs,
 					     struct typed_val_int val);
 static const struct rust_op *ast_slice_type (const struct rust_op *type);
@@ -300,6 +301,9 @@ struct rust_op
      name occurred at the end of the expression and is eligible for
      completion.  */
   unsigned int completing : 1;
+  /* For OP_RANGE, indicates whether the range is inclusive or
+     exclusive.  */
+  unsigned int inclusive : 1;
   /* Operands of expression.  Which one is used and how depends on the
      particular opcode.  */
   RUSTSTYPE left;
@@ -333,6 +337,7 @@ struct rust_op
 
 /* Operator tokens.  */
 %token <voidval> DOTDOT
+%token <voidval> DOTDOTEQ
 %token <voidval> OROR
 %token <voidval> ANDAND
 %token <voidval> EQEQ
@@ -382,7 +387,7 @@ struct rust_op
 %type <one_field_init> struct_expr_tail
 
 /* Precedence.  */
-%nonassoc DOTDOT
+%nonassoc DOTDOT DOTDOTEQ
 %right '=' COMPOUND_ASSIGN
 %left OROR
 %left ANDAND
@@ -535,13 +540,17 @@ array_expr:
 
 range_expr:
 	expr DOTDOT
-		{ $$ = ast_range ($1, NULL); }
+		{ $$ = ast_range ($1, NULL, false); }
 |	expr DOTDOT expr
-		{ $$ = ast_range ($1, $3); }
+		{ $$ = ast_range ($1, $3, false); }
+|	expr DOTDOTEQ expr
+		{ $$ = ast_range ($1, $3, true); }
 |	DOTDOT expr
-		{ $$ = ast_range (NULL, $2); }
+		{ $$ = ast_range (NULL, $2, false); }
+|	DOTDOTEQ expr
+		{ $$ = ast_range (NULL, $2, true); }
 |	DOTDOT
-		{ $$ = ast_range (NULL, NULL); }
+		{ $$ = ast_range (NULL, NULL, false); }
 ;
 
 literal:
@@ -956,6 +965,7 @@ static const struct token_info operator_tokens[] =
   { "&=", COMPOUND_ASSIGN, BINOP_BITWISE_AND },
   { "|=", COMPOUND_ASSIGN, BINOP_BITWISE_IOR },
   { "^=", COMPOUND_ASSIGN, BINOP_BITWISE_XOR },
+  { "..=", DOTDOTEQ, OP_NULL },
 
   { "::", COLONCOLON, OP_NULL },
   { "..", DOTDOT, OP_NULL },
@@ -1841,11 +1851,13 @@ ast_structop_anonymous (const struct rust_op *left,
 /* Make a range operation.  */
 
 static const struct rust_op *
-ast_range (const struct rust_op *lhs, const struct rust_op *rhs)
+ast_range (const struct rust_op *lhs, const struct rust_op *rhs,
+	   bool inclusive)
 {
   struct rust_op *result = OBSTACK_ZALLOC (work_obstack, struct rust_op);
 
   result->opcode = OP_RANGE;
+  result->inclusive = inclusive;
   result->left.op = lhs;
   result->right.op = rhs;
 
@@ -2473,13 +2485,22 @@ convert_ast_to_expression (struct parser_state *state,
 	  {
 	    convert_ast_to_expression (state, operation->right.op, top);
 	    if (kind == BOTH_BOUND_DEFAULT)
-	      kind = LOW_BOUND_DEFAULT;
+	      kind = (operation->inclusive
+		      ? LOW_BOUND_DEFAULT : LOW_BOUND_DEFAULT_EXCLUSIVE);
 	    else
 	      {
 		gdb_assert (kind == HIGH_BOUND_DEFAULT);
-		kind = NONE_BOUND_DEFAULT;
+		kind = (operation->inclusive
+			? NONE_BOUND_DEFAULT : NONE_BOUND_DEFAULT_EXCLUSIVE);
 	      }
 	  }
+	else
+	  {
+	    /* Nothing should make an inclusive range without an upper
+	       bound.  */
+	    gdb_assert (!operation->inclusive);
+	  }
+
 	write_exp_elt_opcode (state, OP_RANGE);
 	write_exp_elt_longcst (state, kind);
 	write_exp_elt_opcode (state, OP_RANGE);
diff --git a/gdb/rust-lang.c b/gdb/rust-lang.c
index cf8a15e..5d1c0a7 100644
--- a/gdb/rust-lang.c
+++ b/gdb/rust-lang.c
@@ -180,6 +180,17 @@ rust_range_type_p (struct type *type)
   return strcmp (TYPE_FIELD_NAME (type, i), "end") == 0;
 }
 
+/* Return true if TYPE is an inclusive range type, otherwise false.
+   This is only valid for types which are already known to be range
+   types.  */
+
+static bool
+rust_inclusive_range_type_p (struct type *type)
+{
+  return (strstr (TYPE_TAG_NAME (type), "::RangeInclusive") != NULL
+	  || strstr (TYPE_TAG_NAME (type), "::RangeToInclusive") != NULL);
+}
+
 /* Return true if TYPE seems to be the type "u8", otherwise false.  */
 
 static bool
@@ -1136,10 +1147,13 @@ rust_range (struct expression *exp, int *pos, enum noside noside)
   kind = (enum range_type) longest_to_int (exp->elts[*pos + 1].longconst);
   *pos += 3;
 
-  if (kind == HIGH_BOUND_DEFAULT || kind == NONE_BOUND_DEFAULT)
+  if (kind == HIGH_BOUND_DEFAULT || kind == NONE_BOUND_DEFAULT
+      || kind == NONE_BOUND_DEFAULT_EXCLUSIVE)
     low = evaluate_subexp (NULL_TYPE, exp, pos, noside);
-  if (kind == LOW_BOUND_DEFAULT || kind == NONE_BOUND_DEFAULT)
+  if (kind == LOW_BOUND_DEFAULT || kind == LOW_BOUND_DEFAULT_EXCLUSIVE
+      || kind == NONE_BOUND_DEFAULT || kind == NONE_BOUND_DEFAULT_EXCLUSIVE)
     high = evaluate_subexp (NULL_TYPE, exp, pos, noside);
+  bool inclusive = (kind == NONE_BOUND_DEFAULT || kind == LOW_BOUND_DEFAULT);
 
   if (noside == EVAL_SKIP)
     return value_from_longest (builtin_type (exp->gdbarch)->builtin_int, 1);
@@ -1154,7 +1168,8 @@ rust_range (struct expression *exp, int *pos, enum noside noside)
       else
 	{
 	  index_type = value_type (high);
-	  name = "std::ops::RangeTo";
+	  name = (inclusive
+		  ? "std::ops::RangeToInclusive" : "std::ops::RangeTo");
 	}
     }
   else
@@ -1169,7 +1184,7 @@ rust_range (struct expression *exp, int *pos, enum noside noside)
 	  if (!types_equal (value_type (low), value_type (high)))
 	    error (_("Range expression with different types"));
 	  index_type = value_type (low);
-	  name = "std::ops::Range";
+	  name = inclusive ? "std::ops::RangeInclusive" : "std::ops::Range";
 	}
     }
 
@@ -1245,6 +1260,9 @@ rust_compute_range (struct type *type, struct value *range,
       *kind = (*kind == BOTH_BOUND_DEFAULT
 	       ? LOW_BOUND_DEFAULT : NONE_BOUND_DEFAULT);
       *high = value_as_long (value_field (range, i));
+
+      if (rust_inclusive_range_type_p (type))
+	++*high;
     }
 }
 
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 34da102..22cf4ff 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-04-27  Tom Tromey  <tom@tromey.com>
+
+	PR rust/22545:
+	* gdb.rust/simple.exp: Add inclusive range tests.
+
 2018-04-26  Pedro Alves  <palves@redhat.com>
 
 	* gdb.base/gnu-ifunc.exp (set-break): Test that GDB resolves
diff --git a/gdb/testsuite/gdb.rust/simple.exp b/gdb/testsuite/gdb.rust/simple.exp
index d70de33..ba90e06 100644
--- a/gdb/testsuite/gdb.rust/simple.exp
+++ b/gdb/testsuite/gdb.rust/simple.exp
@@ -219,7 +219,9 @@ gdb_test "print r###\"###hello\"##" "Unexpected EOF in string"
 gdb_test "print r###\"hello###" "Unexpected EOF in string"
 
 gdb_test "print 0..5" " = .*::ops::Range.* \\{start: 0, end: 5\\}"
+gdb_test "print 0..=5" " = .*::ops::RangeInclusive.* \\{start: 0, end: 5\\}"
 gdb_test "print ..5" " = .*::ops::RangeTo.* \\{end: 5\\}"
+gdb_test "print ..=5" " = .*::ops::RangeToInclusive.* \\{end: 5\\}"
 gdb_test "print 5.." " = .*::ops::RangeFrom.* \\{start: 5\\}"
 gdb_test "print .." " = .*::ops::RangeFull"
 
@@ -244,7 +246,9 @@ proc test_one_slice {svar length base range} {
 }
 
 test_one_slice slice 1 w 2..3
+test_one_slice slice 1 w 2..=2
 test_one_slice slice2 1 slice 0..1
+test_one_slice slice2 1 slice 0..=0
 
 test_one_slice all1 4 w ..
 test_one_slice all2 1 slice ..
@@ -253,7 +257,9 @@ test_one_slice from1 3 w 1..
 test_one_slice from2 0 slice 1..
 
 test_one_slice to1 3 w ..3
+test_one_slice to1 3 w ..=2
 test_one_slice to2 1 slice ..1
+test_one_slice to2 1 slice ..=0
 
 gdb_test "print w\[2..3\]" "Can't take slice of array without '&'"