@@ -757,7 +757,7 @@ write_var_from_sym (struct parser_state *par_state,
struct symbol *sym)
{
if (symbol_read_needs_frame (sym))
- innermost_block.update (block, INNERMOST_BLOCK_FOR_SYMBOLS);
+ par_state->block_tracker->update (block, INNERMOST_BLOCK_FOR_SYMBOLS);
write_exp_elt_opcode (par_state, OP_VAR_VALUE);
write_exp_elt_block (par_state, block);
@@ -125,7 +125,8 @@ static int num_defns_collected (struct obstack *);
static struct block_symbol *defns_collected (struct obstack *, int);
static struct value *resolve_subexp (expression_up *, int *, int,
- struct type *, int);
+ struct type *, int,
+ innermost_block_tracker *);
static void replace_operator_with_call (expression_up *, int, int, int,
struct symbol *, const struct block *);
@@ -3220,7 +3221,8 @@ ada_decoded_op_name (enum exp_opcode op)
return type is preferred. May change (expand) *EXP. */
static void
-resolve (expression_up *expp, int void_context_p, int parse_completion)
+resolve (expression_up *expp, int void_context_p, int parse_completion,
+ innermost_block_tracker *tracker)
{
struct type *context_type = NULL;
int pc = 0;
@@ -3228,7 +3230,7 @@ resolve (expression_up *expp, int void_context_p, int parse_completion)
if (void_context_p)
context_type = builtin_type ((*expp)->gdbarch)->builtin_void;
- resolve_subexp (expp, &pc, 1, context_type, parse_completion);
+ resolve_subexp (expp, &pc, 1, context_type, parse_completion, tracker);
}
/* Resolve the operator of the subexpression beginning at
@@ -3242,7 +3244,8 @@ resolve (expression_up *expp, int void_context_p, int parse_completion)
static struct value *
resolve_subexp (expression_up *expp, int *pos, int deprocedure_p,
- struct type *context_type, int parse_completion)
+ struct type *context_type, int parse_completion,
+ innermost_block_tracker *tracker)
{
int pc = *pos;
int i;
@@ -3267,20 +3270,20 @@ resolve_subexp (expression_up *expp, int *pos, int deprocedure_p,
else
{
*pos += 3;
- resolve_subexp (expp, pos, 0, NULL, parse_completion);
+ resolve_subexp (expp, pos, 0, NULL, parse_completion, tracker);
}
nargs = longest_to_int (exp->elts[pc + 1].longconst);
break;
case UNOP_ADDR:
*pos += 1;
- resolve_subexp (expp, pos, 0, NULL, parse_completion);
+ resolve_subexp (expp, pos, 0, NULL, parse_completion, tracker);
break;
case UNOP_QUAL:
*pos += 3;
resolve_subexp (expp, pos, 1, check_typedef (exp->elts[pc + 1].type),
- parse_completion);
+ parse_completion, tracker);
break;
case OP_ATR_MODULUS:
@@ -3311,11 +3314,12 @@ resolve_subexp (expression_up *expp, int *pos, int deprocedure_p,
struct value *arg1;
*pos += 1;
- arg1 = resolve_subexp (expp, pos, 0, NULL, parse_completion);
+ arg1 = resolve_subexp (expp, pos, 0, NULL, parse_completion, tracker);
if (arg1 == NULL)
- resolve_subexp (expp, pos, 1, NULL, parse_completion);
+ resolve_subexp (expp, pos, 1, NULL, parse_completion, tracker);
else
- resolve_subexp (expp, pos, 1, value_type (arg1), parse_completion);
+ resolve_subexp (expp, pos, 1, value_type (arg1), parse_completion,
+ tracker);
break;
}
@@ -3403,7 +3407,8 @@ resolve_subexp (expression_up *expp, int *pos, int deprocedure_p,
argvec = XALLOCAVEC (struct value *, nargs + 1);
for (i = 0; i < nargs; i += 1)
- argvec[i] = resolve_subexp (expp, pos, 1, NULL, parse_completion);
+ argvec[i] = resolve_subexp (expp, pos, 1, NULL, parse_completion,
+ tracker);
argvec[i] = NULL;
exp = expp->get ();
@@ -3487,7 +3492,7 @@ resolve_subexp (expression_up *expp, int *pos, int deprocedure_p,
exp->elts[pc + 1].block = candidates[i].block;
exp->elts[pc + 2].symbol = candidates[i].symbol;
- innermost_block.update (candidates[i]);
+ tracker->update (candidates[i]);
}
if (deprocedure_p
@@ -3531,7 +3536,7 @@ resolve_subexp (expression_up *expp, int *pos, int deprocedure_p,
exp->elts[pc + 4].block = candidates[i].block;
exp->elts[pc + 5].symbol = candidates[i].symbol;
- innermost_block.update (candidates[i]);
+ tracker->update (candidates[i]);
}
}
break;
@@ -880,11 +880,12 @@ set_breakpoint_condition (struct breakpoint *b, const char *exp,
{
struct watchpoint *w = (struct watchpoint *) b;
+ innermost_block_tracker tracker;
arg = exp;
- w->cond_exp = parse_exp_1 (&arg, 0, 0, 0);
+ w->cond_exp = parse_exp_1 (&arg, 0, 0, 0, &tracker);
if (*arg)
error (_("Junk at end of expression"));
- w->cond_exp_valid_block = innermost_block.block ();
+ w->cond_exp_valid_block = tracker.block ();
}
else
{
@@ -10603,7 +10604,8 @@ watch_command_1 (const char *arg, int accessflag, int from_tty,
ARG. */
std::string expression (arg, exp_end - arg);
exp_start = arg = expression.c_str ();
- expression_up exp = parse_exp_1 (&arg, 0, 0, 0);
+ innermost_block_tracker tracker;
+ expression_up exp = parse_exp_1 (&arg, 0, 0, 0, &tracker);
exp_end = arg;
/* Remove trailing whitespace from the expression before saving it.
This makes the eventual display of the expression string a bit
@@ -10622,7 +10624,7 @@ watch_command_1 (const char *arg, int accessflag, int from_tty,
error (_("Cannot watch constant value `%.*s'."), len, exp_start);
}
- exp_valid_block = innermost_block.block ();
+ exp_valid_block = tracker.block ();
struct value *mark = value_mark ();
struct value *val_as_value = nullptr;
fetch_subexp_value (exp.get (), &pc, &val_as_value, &result, NULL,
@@ -10663,11 +10665,12 @@ watch_command_1 (const char *arg, int accessflag, int from_tty,
if (toklen >= 1 && strncmp (tok, "if", toklen) == 0)
{
tok = cond_start = end_tok + 1;
- parse_exp_1 (&tok, 0, 0, 0);
+ innermost_block_tracker if_tracker;
+ parse_exp_1 (&tok, 0, 0, 0, &if_tracker);
/* The watchpoint expression may not be local, but the condition
may still be. E.g.: `watch global if local > 0'. */
- cond_exp_valid_block = innermost_block.block ();
+ cond_exp_valid_block = if_tracker.block ();
cond_end = tok;
}
@@ -1002,8 +1002,7 @@ variable: block COLONCOLON name
error (_("No symbol \"%s\" in specified context."),
copy_name ($3));
if (symbol_read_needs_frame (sym.symbol))
-
- innermost_block.update (sym);
+ pstate->block_tracker->update (sym);
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
write_exp_elt_block (pstate, sym.block);
@@ -1092,7 +1091,7 @@ variable: name_not_typename
if (sym.symbol)
{
if (symbol_read_needs_frame (sym.symbol))
- innermost_block.update (sym);
+ pstate->block_tracker->update (sym);
/* If we found a function, see if it's
an ifunc resolver that has the same
@@ -1116,7 +1115,7 @@ variable: name_not_typename
/* C++: it hangs off of `this'. Must
not inadvertently convert from a method call
to data ref. */
- innermost_block.update (sym);
+ pstate->block_tracker->update (sym);
write_exp_elt_opcode (pstate, OP_THIS);
write_exp_elt_opcode (pstate, OP_THIS);
write_exp_elt_opcode (pstate, STRUCTOP_PTR);
@@ -425,7 +425,7 @@ PrimaryExpression:
if (sym.symbol && SYMBOL_CLASS (sym.symbol) != LOC_TYPEDEF)
{
if (symbol_read_needs_frame (sym.symbol))
- innermost_block.update (sym);
+ pstate->block_tracker->update (sym);
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
write_exp_elt_block (pstate, sym.block);
write_exp_elt_sym (pstate, sym.symbol);
@@ -435,7 +435,7 @@ PrimaryExpression:
{
/* It hangs off of `this'. Must not inadvertently convert from a
method call to data ref. */
- innermost_block.update (sym);
+ pstate->block_tracker->update (sym);
write_exp_elt_opcode (pstate, OP_THIS);
write_exp_elt_opcode (pstate, OP_THIS);
write_exp_elt_opcode (pstate, STRUCTOP_PTR);
@@ -110,7 +110,9 @@ typedef gdb::unique_xmalloc_ptr<expression> expression_up;
/* From parse.c */
-extern expression_up parse_expression (const char *);
+class innermost_block_tracker;
+extern expression_up parse_expression (const char *,
+ innermost_block_tracker * = nullptr);
extern expression_up parse_expression_with_language (const char *string,
enum language lang);
@@ -118,10 +120,10 @@ extern expression_up parse_expression_with_language (const char *string,
extern struct type *parse_expression_for_completion
(const char *, gdb::unique_xmalloc_ptr<char> *, enum type_code *);
+class innermost_block_tracker;
extern expression_up parse_exp_1 (const char **, CORE_ADDR pc,
const struct block *, int,
- innermost_block_tracker_types
- = INNERMOST_BLOCK_FOR_SYMBOLS);
+ innermost_block_tracker * = nullptr);
/* From eval.c */
@@ -480,7 +480,7 @@ variable: name_not_typename
if (sym.symbol)
{
if (symbol_read_needs_frame (sym.symbol))
- innermost_block.update (sym);
+ pstate->block_tracker->update (sym);
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
write_exp_elt_block (pstate, sym.block);
write_exp_elt_sym (pstate, sym.symbol);
@@ -552,7 +552,7 @@ variable: name_not_typename
if (sym.symbol)
{
if (symbol_read_needs_frame (sym.symbol))
- innermost_block.update (sym);
+ pstate->block_tracker->update (sym);
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
write_exp_elt_block (pstate, sym.block);
@@ -38,6 +38,7 @@ struct lang_varobj_ops;
struct parser_state;
class compile_instance;
struct completion_match_for_lcd;
+class innermost_block_tracker;
#define MAX_FORTRAN_DIMS 7 /* Maximum number of F77 array dims. */
@@ -181,7 +182,7 @@ struct language_defn
for completion, not evaluation. */
void (*la_post_parser) (expression_up *expp, int void_context_p,
- int completing);
+ int completing, innermost_block_tracker *tracker);
void (*la_printchar) (int ch, struct type *chtype,
struct ui_file * stream);
@@ -548,7 +548,7 @@ variable: block COLONCOLON NAME
error (_("No symbol \"%s\" in specified context."),
copy_name ($3));
if (symbol_read_needs_frame (sym.symbol))
- innermost_block.update (sym);
+ pstate->block_tracker->update (sym);
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
write_exp_elt_block (pstate, sym.block);
@@ -570,7 +570,7 @@ variable: NAME
if (sym.symbol)
{
if (symbol_read_needs_frame (sym.symbol))
- innermost_block.update (sym);
+ pstate->block_tracker->update (sym);
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
write_exp_elt_block (pstate, sym.block);
@@ -712,7 +712,7 @@ variable: name_not_typename
if (sym.symbol)
{
if (symbol_read_needs_frame (sym.symbol))
- innermost_block.update (sym);
+ pstate->block_tracker->update (sym);
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
write_exp_elt_block (pstate, sym.block);
@@ -726,7 +726,7 @@ variable: name_not_typename
/* Object pascal: it hangs off of `this'. Must
not inadvertently convert from a method call
to data ref. */
- innermost_block.update (sym);
+ pstate->block_tracker->update (sym);
write_exp_elt_opcode (pstate, OP_THIS);
write_exp_elt_opcode (pstate, OP_THIS);
write_exp_elt_opcode (pstate, STRUCTOP_PTR);
@@ -65,10 +65,6 @@ const struct exp_descriptor exp_descriptor_standard =
evaluate_subexp_standard
};
-/* Global variables declared in parser-defs.h (and commented there). */
-innermost_block_tracker innermost_block;
-
-
static unsigned int expressiondebug = 0;
static void
show_expressiondebug (struct ui_file *file, int from_tty,
@@ -95,7 +91,7 @@ static int prefixify_subexp (struct expression *, struct expression *, int,
static expression_up parse_exp_in_context (const char **, CORE_ADDR,
const struct block *, int,
int, int *,
- innermost_block_tracker_types,
+ innermost_block_tracker *,
expr_completion_state *);
static void increase_expout_size (struct expr_builder *ps, size_t lenelt);
@@ -637,8 +633,8 @@ handle_register:
str.ptr++;
write_exp_string (ps, str);
write_exp_elt_opcode (ps, OP_REGISTER);
- innermost_block.update (ps->expression_context_block,
- INNERMOST_BLOCK_FOR_REGISTERS);
+ ps->block_tracker->update (ps->expression_context_block,
+ INNERMOST_BLOCK_FOR_REGISTERS);
return;
}
@@ -1049,10 +1045,10 @@ prefixify_subexp (struct expression *inexpr,
expression_up
parse_exp_1 (const char **stringptr, CORE_ADDR pc, const struct block *block,
- int comma, innermost_block_tracker_types tracker_types)
+ int comma, innermost_block_tracker *tracker)
{
return parse_exp_in_context (stringptr, pc, block, comma, 0, NULL,
- tracker_types, nullptr);
+ tracker, nullptr);
}
/* As for parse_exp_1, except that if VOID_CONTEXT_P, then
@@ -1066,20 +1062,22 @@ static expression_up
parse_exp_in_context (const char **stringptr, CORE_ADDR pc,
const struct block *block,
int comma, int void_context_p, int *out_subexp,
- innermost_block_tracker_types tracker_types,
+ innermost_block_tracker *tracker,
expr_completion_state *cstate)
{
const struct language_defn *lang = NULL;
int subexp;
- innermost_block.reset (tracker_types);
-
if (*stringptr == 0 || **stringptr == 0)
error_no_arg (_("expression to compute"));
const struct block *expression_context_block = block;
CORE_ADDR expression_context_pc = 0;
+ innermost_block_tracker local_tracker;
+ if (tracker == nullptr)
+ tracker = &local_tracker;
+
/* If no context specified, try using the current frame, if any. */
if (!expression_context_block)
expression_context_block = get_selected_block (&expression_context_pc);
@@ -1134,7 +1132,7 @@ parse_exp_in_context (const char **stringptr, CORE_ADDR pc,
parser_state ps (lang, get_current_arch (), expression_context_block,
expression_context_pc, comma, *stringptr,
- cstate != nullptr);
+ cstate != nullptr, tracker);
scoped_restore_current_language lang_saver;
set_language (lang->la_language);
@@ -1169,7 +1167,8 @@ parse_exp_in_context (const char **stringptr, CORE_ADDR pc,
if (out_subexp)
*out_subexp = subexp;
- lang->la_post_parser (&result, void_context_p, ps.parse_completion);
+ lang->la_post_parser (&result, void_context_p, ps.parse_completion,
+ tracker);
if (expressiondebug)
dump_prefix_expression (result.get (), gdb_stdlog);
@@ -1184,9 +1183,9 @@ parse_exp_in_context (const char **stringptr, CORE_ADDR pc,
to use up all of the contents of STRING. */
expression_up
-parse_expression (const char *string)
+parse_expression (const char *string, innermost_block_tracker *tracker)
{
- expression_up exp = parse_exp_1 (&string, 0, 0, 0);
+ expression_up exp = parse_exp_1 (&string, 0, 0, 0, tracker);
if (*string)
error (_("Junk after end of expression."));
return exp;
@@ -1228,7 +1227,7 @@ parse_expression_for_completion (const char *string,
TRY
{
exp = parse_exp_in_context (&string, 0, 0, 0, 0, &subexp,
- INNERMOST_BLOCK_FOR_SYMBOLS, &cstate);
+ nullptr, &cstate);
}
CATCH (except, RETURN_MASK_ERROR)
{
@@ -1267,7 +1266,8 @@ parse_expression_for_completion (const char *string,
/* A post-parser that does nothing. */
void
-null_post_parser (expression_up *exp, int void_context_p, int completin)
+null_post_parser (expression_up *exp, int void_context_p, int completin,
+ innermost_block_tracker *tracker)
{
}
@@ -29,6 +29,7 @@
struct block;
struct language_defn;
struct internalvar;
+class innermost_block_tracker;
extern int parser_debug;
@@ -107,13 +108,15 @@ struct parser_state : public expr_builder
CORE_ADDR context_pc,
int comma,
const char *input,
- int completion)
+ int completion,
+ innermost_block_tracker *tracker)
: expr_builder (lang, gdbarch),
expression_context_block (context_block),
expression_context_pc (context_pc),
comma_terminates (comma),
lexptr (input),
- parse_completion (completion)
+ parse_completion (completion),
+ block_tracker (tracker)
{
}
@@ -186,6 +189,9 @@ struct parser_state : public expr_builder
/* Completion state is updated here. */
expr_completion_state m_completion_state;
+ /* The innermost block tracker. */
+ innermost_block_tracker *block_tracker;
+
private:
/* Data structure for saving values of arglist_len for function calls whose
@@ -200,21 +206,12 @@ private:
class innermost_block_tracker
{
public:
- innermost_block_tracker ()
- : m_types (INNERMOST_BLOCK_FOR_SYMBOLS),
+ innermost_block_tracker (innermost_block_tracker_types types
+ = INNERMOST_BLOCK_FOR_SYMBOLS)
+ : m_types (types),
m_innermost_block (NULL)
{ /* Nothing. */ }
- /* Reset the currently stored innermost block. Usually called before
- parsing a new expression. As the most common case is that we only
- want to gather the innermost block for symbols in an expression, this
- becomes the default block tracker type. */
- void reset (innermost_block_tracker_types t = INNERMOST_BLOCK_FOR_SYMBOLS)
- {
- m_types = t;
- m_innermost_block = NULL;
- }
-
/* Update the stored innermost block if the new block B is more inner
than the currently stored block, or if no block is stored yet. The
type T tells us whether the block B was for a symbol or for a
@@ -246,12 +243,6 @@ private:
const struct block *m_innermost_block;
};
-/* The innermost context required by the stack and register variables
- we've encountered so far. This is cleared by the expression
- parsing functions before parsing an expression, and can queried
- once the parse is complete. */
-extern innermost_block_tracker innermost_block;
-
/* A string token, either a char-string or bit-string. Char-strings are
used, for example, for the names of symbols. */
@@ -359,7 +350,8 @@ extern int operator_check_standard (struct expression *exp, int pos,
extern const char *op_name_standard (enum exp_opcode);
-extern void null_post_parser (expression_up *, int, int);
+extern void null_post_parser (expression_up *, int, int,
+ innermost_block_tracker *);
extern bool parse_float (const char *p, int len,
const struct type *type, gdb_byte *data);
@@ -1715,13 +1715,14 @@ display_command (const char *arg, int from_tty)
fmt.raw = 0;
}
- expression_up expr = parse_expression (exp);
+ innermost_block_tracker tracker;
+ expression_up expr = parse_expression (exp, &tracker);
newobj = new display ();
newobj->exp_string = xstrdup (exp);
newobj->exp = std::move (expr);
- newobj->block = innermost_block.block ();
+ newobj->block = tracker.block ();
newobj->pspace = current_program_space;
newobj->number = ++display_number;
newobj->format = fmt;
@@ -1882,8 +1883,9 @@ do_one_display (struct display *d)
TRY
{
- d->exp = parse_expression (d->exp_string);
- d->block = innermost_block.block ();
+ innermost_block_tracker tracker;
+ d->exp = parse_expression (d->exp_string, &tracker);
+ d->block = tracker.block ();
}
CATCH (ex, RETURN_MASK_ALL)
{
@@ -118,9 +118,6 @@ static int rustyylex (YYSTYPE *, rust_parser *);
static void rustyyerror (rust_parser *parser, const char *msg);
static struct stoken make_stoken (const char *);
-static struct block_symbol rust_lookup_symbol (const char *name,
- const struct block *block,
- const domain_enum domain);
/* A regular expression for matching Rust numbers. This is split up
since it is very long and this gives us a way to comment the
@@ -241,6 +238,10 @@ struct rust_parser
int lex_operator (YYSTYPE *lvalp);
void push_back (char c);
+ void update_innermost_block (struct block_symbol sym);
+ struct block_symbol lookup_symbol (const char *name,
+ const struct block *block,
+ const domain_enum domain);
struct type *rust_lookup_type (const char *name, const struct block *block);
std::vector<struct type *> convert_params_to_types (rust_op_vector *params);
struct type *convert_ast_to_type (const struct rust_op *operation);
@@ -1104,11 +1105,11 @@ rust_parser::super_name (const struct rust_op *ident, unsigned int n_supers)
/* A helper that updates the innermost block as appropriate. */
-static void
-update_innermost_block (struct block_symbol sym)
+void
+rust_parser::update_innermost_block (struct block_symbol sym)
{
if (symbol_read_needs_frame (sym.symbol))
- innermost_block.update (sym);
+ pstate->block_tracker->update (sym);
}
/* Lex a hex number with at least MIN digits and at most MAX
@@ -1992,15 +1993,15 @@ munge_name_and_block (const char **name, const struct block **block)
/* Like lookup_symbol, but handles Rust namespace conventions, and
doesn't require field_of_this_result. */
-static struct block_symbol
-rust_lookup_symbol (const char *name, const struct block *block,
- const domain_enum domain)
+struct block_symbol
+rust_parser::lookup_symbol (const char *name, const struct block *block,
+ const domain_enum domain)
{
struct block_symbol result;
munge_name_and_block (&name, &block);
- result = lookup_symbol (name, block, domain, NULL);
+ result = ::lookup_symbol (name, block, domain, NULL);
if (result.symbol != NULL)
update_innermost_block (result);
return result;
@@ -2016,7 +2017,7 @@ rust_parser::rust_lookup_type (const char *name, const struct block *block)
munge_name_and_block (&name, &block);
- result = lookup_symbol (name, block, STRUCT_DOMAIN, NULL);
+ result = ::lookup_symbol (name, block, STRUCT_DOMAIN, NULL);
if (result.symbol != NULL)
{
update_innermost_block (result);
@@ -2387,8 +2388,8 @@ rust_parser::convert_ast_to_expression (const struct rust_op *operation,
}
varname = convert_name (operation);
- sym = rust_lookup_symbol (varname, pstate->expression_context_block,
- VAR_DOMAIN);
+ sym = lookup_symbol (varname, pstate->expression_context_block,
+ VAR_DOMAIN);
if (sym.symbol != NULL && SYMBOL_CLASS (sym.symbol) != LOC_TYPEDEF)
{
write_exp_elt_opcode (pstate, OP_VAR_VALUE);
@@ -2726,7 +2727,7 @@ rust_lex_tests (void)
// Set up dummy "parser", so that rust_type works.
struct parser_state ps (&rust_language_defn, target_gdbarch (),
- nullptr, 0, 0, nullptr, 0);
+ nullptr, 0, 0, nullptr, 0, nullptr);
rust_parser parser (&ps);
rust_lex_test_one (&parser, "", 0);
@@ -309,13 +309,14 @@ varobj_create (const char *objname,
}
p = expression;
+
+ innermost_block_tracker tracker (INNERMOST_BLOCK_FOR_SYMBOLS
+ | INNERMOST_BLOCK_FOR_REGISTERS);
/* Wrap the call to parse expression, so we can
return a sensible error. */
TRY
{
- var->root->exp = parse_exp_1 (&p, pc, block, 0,
- INNERMOST_BLOCK_FOR_SYMBOLS
- | INNERMOST_BLOCK_FOR_REGISTERS);
+ var->root->exp = parse_exp_1 (&p, pc, block, 0, &tracker);
}
CATCH (except, RETURN_MASK_ERROR)
@@ -336,7 +337,7 @@ varobj_create (const char *objname,
var->format = variable_default_display (var.get ());
var->root->valid_block =
- var->root->floating ? NULL : innermost_block.block ();
+ var->root->floating ? NULL : tracker.block ();
var->name = expression;
/* For a root var, the name and the expr are the same. */
var->path_expr = expression;