[PATCH 185/203] Remove now-unused Rust evaluator code

Tom Tromey
2021-01-01T21:49:47Z

Now that the Rust parser has switched to the new style, there is no
need for the old Rust evaluation code.

gdb/ChangeLog
2021-01-01 Tom Tromey <tom@tromey.com>

* rust-lang.h (class rust_language) <expression_ops,
exp_descriptor_tab>: Remove.
* rust-lang.c (rust_evaluate_funcall): Remove.
(rust_range, rust_subscript, eval_op_rust_complement): Don't use
EVAL_SKIP.
(rust_evaluate_subexp): Remove.
(rust_aggregate_operation::evaluate): Don't use EVAL_SKIP.
(rust_operator_length, rust_dump_subexp_body, rust_print_subexp)
(rust_operator_check, rust_language::exp_descriptor_tab): Remove.
---
gdb/ChangeLog | 12 ++
gdb/rust-lang.c | 507 +-----------------------------------------------
gdb/rust-lang.h | 10 -
3 files changed, 13 insertions(+), 516 deletions(-)

diff --git a/gdb/rust-lang.c b/gdb/rust-lang.c
index 7605b64b384..5a4a4bb9937 100644
--- a/gdb/rust-lang.c
+++ b/gdb/rust-lang.c
@@ -963,82 +963,6 @@ rust_slice_type (const char *name, struct type *elt_type,

\f

-/* A helper for rust_evaluate_subexp that handles OP_FUNCALL. */
-
-static struct value *
-rust_evaluate_funcall (struct expression *exp, int *pos, enum noside noside)
-{
- int i;
- int num_args = exp->elts[*pos + 1].longconst;
- const char *method;
- struct value *function, *result, *arg0;
- struct type *type, *fn_type;
- const struct block *block;
- struct block_symbol sym;
-
- /* For an ordinary function call we can simply defer to the
- generic implementation. */
- if (exp->elts[*pos + 3].opcode != STRUCTOP_STRUCT)
- return evaluate_subexp_standard (NULL, exp, pos, noside);
-
- /* Skip over the OP_FUNCALL and the STRUCTOP_STRUCT. */
- *pos += 4;
- method = &exp->elts[*pos + 1].string;
- *pos += 3 + BYTES_TO_EXP_ELEM (exp->elts[*pos].longconst + 1);
-
- /* Evaluate the argument to STRUCTOP_STRUCT, then find its
- type in order to look up the method. */
- arg0 = evaluate_subexp (nullptr, exp, pos, noside);
-
- if (noside == EVAL_SKIP)
- {
- for (i = 0; i < num_args; ++i)
- evaluate_subexp (nullptr, exp, pos, noside);
- return arg0;
- }
-
- std::vector<struct value *> args (num_args + 1);
- args[0] = arg0;
-
- /* We don't yet implement real Deref semantics. */
- while (value_type (args[0])->code () == TYPE_CODE_PTR)
- args[0] = value_ind (args[0]);
-
- type = value_type (args[0]);
- if ((type->code () != TYPE_CODE_STRUCT
- && type->code () != TYPE_CODE_UNION
- && type->code () != TYPE_CODE_ENUM)
- || rust_tuple_type_p (type))
- error (_("Method calls only supported on struct or enum types"));
- if (type->name () == NULL)
- error (_("Method call on nameless type"));
-
- std::string name = std::string (type->name ()) + "::" + method;
-
- block = get_selected_block (0);
- sym = lookup_symbol (name.c_str (), block, VAR_DOMAIN, NULL);
- if (sym.symbol == NULL)
- error (_("Could not find function named '%s'"), name.c_str ());
-
- fn_type = SYMBOL_TYPE (sym.symbol);
- if (fn_type->num_fields () == 0)
- error (_("Function '%s' takes no arguments"), name.c_str ());
-
- if (fn_type->field (0).type ()->code () == TYPE_CODE_PTR)
- args[0] = value_addr (args[0]);
-
- function = address_of_variable (sym.symbol, block);
-
- for (i = 0; i < num_args; ++i)
- args[i + 1] = evaluate_subexp (nullptr, exp, pos, noside);
-
- if (noside == EVAL_AVOID_SIDE_EFFECTS)
- result = value_zero (TYPE_TARGET_TYPE (fn_type), not_lval);
- else
- result = call_function_by_hand (function, NULL, args);
- return result;
-}
-
/* A helper for rust_evaluate_subexp that handles OP_RANGE. */

struct value *
@@ -1055,9 +979,6 @@ rust_range (struct type *expect_type, struct expression *exp,

bool inclusive = !(kind & RANGE_HIGH_BOUND_EXCLUSIVE);

- if (noside == EVAL_SKIP)
- return value_from_longest (builtin_type (exp->gdbarch)->builtin_int, 1);
-
if (low == NULL)
{
if (high == NULL)
@@ -1181,9 +1102,6 @@ rust_subscript (struct type *expect_type, struct expression *exp,
LONGEST high = 0;
int want_slice = 0;

- if (noside == EVAL_SKIP)
- return lhs;
-
rhstype = check_typedef (value_type (rhs));
if (rust_range_type_p (rhstype))
{
@@ -1347,11 +1265,6 @@ eval_op_rust_complement (struct type *expect_type, struct expression *exp,
enum exp_opcode opcode,
struct value *value)
{
- if (noside == EVAL_SKIP)
- {
- /* Preserving the type is enough. */
- return value;
- }
if (value_type (value)->code () == TYPE_CODE_BOOL)
return value_from_longest (value_type (value), value_logical_not (value));
return value_complement (value);
@@ -1502,204 +1415,6 @@ eval_op_rust_structop (struct type *expect_type, struct expression *exp,
return result;
}

-/* evaluate_exp implementation for Rust. */
-
-static struct value *
-rust_evaluate_subexp (struct type *expect_type, struct expression *exp,
- int *pos, enum noside noside)
-{
- struct value *result;
- enum exp_opcode op = exp->elts[*pos].opcode;
-
- switch (op)
- {
- case UNOP_IND:
- {
- if (noside != EVAL_NORMAL)
- result = evaluate_subexp_standard (expect_type, exp, pos, noside);
- else
- {
- ++*pos;
- struct value *value = evaluate_subexp (expect_type, exp, pos,
- noside);
- result = eval_op_rust_ind (expect_type, exp, noside, op, value);
- }
- }
- break;
-
- case UNOP_COMPLEMENT:
- {
- struct value *value;
-
- ++*pos;
- value = evaluate_subexp (nullptr, exp, pos, noside);
- result = eval_op_rust_complement (expect_type, exp, noside, op, value);
- }
- break;
-
- case BINOP_SUBSCRIPT:
- {
- ++*pos;
- struct value *lhs = evaluate_subexp (nullptr, exp, pos, noside);
- struct value *rhs = evaluate_subexp (nullptr, exp, pos, noside);
- result = rust_subscript (expect_type, exp, noside, false, lhs, rhs);
- }
- break;
-
- case OP_FUNCALL:
- result = rust_evaluate_funcall (exp, pos, noside);
- break;
-
- case OP_AGGREGATE:
- {
- int pc = (*pos)++;
- struct type *type = exp->elts[pc + 1].type;
- int arglen = longest_to_int (exp->elts[pc + 2].longconst);
- int i;
- CORE_ADDR addr = 0;
- struct value *addrval = NULL;
-
- *pos += 3;
-
- if (noside == EVAL_NORMAL)
- {
- addrval = value_allocate_space_in_inferior (TYPE_LENGTH (type));
- addr = value_as_long (addrval);
- result = value_at_lazy (type, addr);
- }
-
- if (arglen > 0 && exp->elts[*pos].opcode == OP_OTHERS)
- {
- struct value *init;
-
- ++*pos;
- init = rust_evaluate_subexp (NULL, exp, pos, noside);
- if (noside == EVAL_NORMAL)
- {
- /* This isn't quite right but will do for the time
- being, seeing that we can't implement the Copy
- trait anyway. */
- value_assign (result, init);
- }
-
- --arglen;
- }
-
- gdb_assert (arglen % 2 == 0);
- for (i = 0; i < arglen; i += 2)
- {
- int len;
- const char *fieldname;
- struct value *value, *field;
-
- gdb_assert (exp->elts[*pos].opcode == OP_NAME);
- ++*pos;
- len = longest_to_int (exp->elts[*pos].longconst);
- ++*pos;
- fieldname = &exp->elts[*pos].string;
- *pos += 2 + BYTES_TO_EXP_ELEM (len + 1);
-
- value = rust_evaluate_subexp (NULL, exp, pos, noside);
- if (noside == EVAL_NORMAL)
- {
- field = value_struct_elt (&result, NULL, fieldname, NULL,
- "structure");
- value_assign (field, value);
- }
- }
-
- if (noside == EVAL_SKIP)
- return value_from_longest (builtin_type (exp->gdbarch)->builtin_int,
- 1);
- else if (noside == EVAL_AVOID_SIDE_EFFECTS)
- result = allocate_value (type);
- else
- result = value_at_lazy (type, addr);
- }
- break;
-
- case OP_RUST_ARRAY:
- {
- (*pos)++;
- struct value *elt;
- struct value *ncopies;
-
- elt = rust_evaluate_subexp (NULL, exp, pos, noside);
- ncopies = rust_evaluate_subexp (NULL, exp, pos, noside);
- return eval_op_rust_array (expect_type, exp, noside, op, elt, ncopies);
- }
- break;
-
- case STRUCTOP_ANONYMOUS:
- {
- /* Anonymous field access, i.e. foo.1. */
- struct value *lhs;
- int pc, field_number;
-
- pc = (*pos)++;
- field_number = longest_to_int (exp->elts[pc + 1].longconst);
- (*pos) += 2;
- lhs = evaluate_subexp (nullptr, exp, pos, noside);
-
- return eval_op_rust_struct_anon (expect_type, exp, noside,
- field_number, lhs);
- }
- break;
-
- case STRUCTOP_STRUCT:
- {
- struct value *lhs;
- int tem, pc;
-
- pc = (*pos)++;
- tem = longest_to_int (exp->elts[pc + 1].longconst);
- (*pos) += 3 + BYTES_TO_EXP_ELEM (tem + 1);
- lhs = evaluate_subexp (nullptr, exp, pos, noside);
-
- const char *field_name = &exp->elts[pc + 2].string;
- return eval_op_rust_structop (expect_type, exp, noside, lhs,
- field_name);
- }
- break;
-
- case OP_RANGE:
- {
- struct value *low = NULL, *high = NULL;
- auto kind
- = (enum range_flag) longest_to_int (exp->elts[*pos + 1].longconst);
- *pos += 3;
-
- if (!(kind & RANGE_LOW_BOUND_DEFAULT))
- low = evaluate_subexp (nullptr, exp, pos, noside);
- if (!(kind & RANGE_HIGH_BOUND_DEFAULT))
- high = evaluate_subexp (nullptr, exp, pos, noside);
-
- result = rust_range (expect_type, exp, noside, kind, low, high);
- }
- break;
-
- case UNOP_ADDR:
- /* We might have &array[range], in which case we need to make a
- slice. */
- if (exp->elts[*pos + 1].opcode == BINOP_SUBSCRIPT)
- {
- ++*pos;
- ++*pos;
- struct value *lhs = evaluate_subexp (nullptr, exp, pos, noside);
- struct value *rhs = evaluate_subexp (nullptr, exp, pos, noside);
-
- result = rust_subscript (expect_type, exp, noside, true, lhs, rhs);
- break;
- }
- /* Fall through. */
- default:
- result = evaluate_subexp_standard (expect_type, exp, pos, noside);
- break;
- }
-
- return result;
-}
-
namespace expr
{

@@ -1746,9 +1461,7 @@ rust_aggregate_operation::evaluate (struct type *expect_type,
}
}

- if (noside == EVAL_SKIP)
- result = value_from_longest (builtin_type (exp->gdbarch)->builtin_int, 1);
- else if (noside == EVAL_AVOID_SIDE_EFFECTS)
+ if (noside == EVAL_AVOID_SIDE_EFFECTS)
result = allocate_value (type);
else
result = value_at_lazy (type, addr);
@@ -1808,226 +1521,8 @@ rust_structop::evaluate_funcall (struct type *expect_type,

}

-/* operator_length implementation for Rust. */
-
-static void
-rust_operator_length (const struct expression *exp, int pc, int *oplenp,
- int *argsp)
-{
- int oplen = 1;
- int args = 0;
-
- switch (exp->elts[pc - 1].opcode)
- {
- case OP_AGGREGATE:
- /* We handle aggregate as a type and argument count. The first
- argument might be OP_OTHERS. After that the arguments
- alternate: first an OP_NAME, then an expression. */
- oplen = 4;
- args = longest_to_int (exp->elts[pc - 2].longconst);
- break;
-
- case OP_OTHERS:
- oplen = 1;
- args = 1;
- break;
-
- case STRUCTOP_ANONYMOUS:
- oplen = 3;
- args = 1;
- break;
-
- case OP_RUST_ARRAY:
- oplen = 1;
- args = 2;
- break;
-
- default:
- operator_length_standard (exp, pc, oplenp, argsp);
- return;
- }
-
- *oplenp = oplen;
- *argsp = args;
-}
-
-/* dump_subexp_body implementation for Rust. */
-
-static int
-rust_dump_subexp_body (struct expression *exp, struct ui_file *stream,
- int elt)
-{
- switch (exp->elts[elt].opcode)
- {
- case OP_AGGREGATE:
- {
- int length = longest_to_int (exp->elts[elt + 2].longconst);
- int i;
-
- fprintf_filtered (stream, "Type @");
- gdb_print_host_address (exp->elts[elt + 1].type, stream);
- fprintf_filtered (stream, " (");
- type_print (exp->elts[elt + 1].type, NULL, stream, 0);
- fprintf_filtered (stream, "), length %d", length);
-
- elt += 4;
- for (i = 0; i < length; ++i)
- elt = dump_subexp (exp, stream, elt);
- }
- break;
-
- case OP_STRING:
- case OP_NAME:
- {
- LONGEST len = exp->elts[elt + 1].longconst;
-
- fprintf_filtered (stream, "%s: %s",
- (exp->elts[elt].opcode == OP_STRING
- ? "string" : "name"),
- &exp->elts[elt + 2].string);
- elt += 4 + BYTES_TO_EXP_ELEM (len + 1);
- }
- break;
-
- case OP_OTHERS:
- elt = dump_subexp (exp, stream, elt + 1);
- break;
-
- case STRUCTOP_ANONYMOUS:
- {
- int field_number;
-
- field_number = longest_to_int (exp->elts[elt + 1].longconst);
-
- fprintf_filtered (stream, "Field number: %d", field_number);
- elt = dump_subexp (exp, stream, elt + 3);
- }
- break;
-
- case OP_RUST_ARRAY:
- ++elt;
- break;
-
- default:
- elt = dump_subexp_body_standard (exp, stream, elt);
- break;
- }
-
- return elt;
-}
-
-/* print_subexp implementation for Rust. */
-
-static void
-rust_print_subexp (struct expression *exp, int *pos, struct ui_file *stream,
- enum precedence prec)
-{
- switch (exp->elts[*pos].opcode)
- {
- case OP_AGGREGATE:
- {
- int length = longest_to_int (exp->elts[*pos + 2].longconst);
- int i;
-
- type_print (exp->elts[*pos + 1].type, "", stream, 0);
- fputs_filtered (" { ", stream);
-
- *pos += 4;
- for (i = 0; i < length; ++i)
- {
- rust_print_subexp (exp, pos, stream, prec);
- fputs_filtered (", ", stream);
- }
- fputs_filtered (" }", stream);
- }
- break;
-
- case OP_NAME:
- {
- LONGEST len = exp->elts[*pos + 1].longconst;
-
- fputs_filtered (&exp->elts[*pos + 2].string, stream);
- *pos += 4 + BYTES_TO_EXP_ELEM (len + 1);
- }
- break;
-
- case OP_OTHERS:
- {
- fputs_filtered ("<<others>> (", stream);
- ++*pos;
- rust_print_subexp (exp, pos, stream, prec);
- fputs_filtered (")", stream);
- }
- break;
-
- case STRUCTOP_ANONYMOUS:
- {
- int tem = longest_to_int (exp->elts[*pos + 1].longconst);
-
- (*pos) += 3;
- print_subexp (exp, pos, stream, PREC_SUFFIX);
- fprintf_filtered (stream, ".%d", tem);
- }
- break;
-
- case OP_RUST_ARRAY:
- ++*pos;
- fprintf_filtered (stream, "[");
- rust_print_subexp (exp, pos, stream, prec);
- fprintf_filtered (stream, "; ");
- rust_print_subexp (exp, pos, stream, prec);
- fprintf_filtered (stream, "]");
- break;
-
- default:
- print_subexp_standard (exp, pos, stream, prec);
- break;
- }
-}
-
-/* operator_check implementation for Rust. */
-
-static int
-rust_operator_check (struct expression *exp, int pos,
- int (*objfile_func) (struct objfile *objfile,
- void *data),
- void *data)
-{
- switch (exp->elts[pos].opcode)
- {
- case OP_AGGREGATE:
- {
- struct type *type = exp->elts[pos + 1].type;
- struct objfile *objfile = TYPE_OBJFILE (type);
-
- if (objfile != NULL && (*objfile_func) (objfile, data))
- return 1;
- }
- break;
-
- case OP_OTHERS:
- case OP_NAME:
- case OP_RUST_ARRAY:
- break;
-
- default:
- return operator_check_standard (exp, pos, objfile_func, data);
- }
-
- return 0;
-}
-
\f

-const struct exp_descriptor rust_language::exp_descriptor_tab =
-{
- rust_print_subexp,
- rust_operator_length,
- rust_operator_check,
- rust_dump_subexp_body,
- rust_evaluate_subexp
-};
-
/* See language.h. */

void
diff --git a/gdb/rust-lang.h b/gdb/rust-lang.h
index fb27f60eeab..ec97cac3dae 100644
--- a/gdb/rust-lang.h
+++ b/gdb/rust-lang.h
@@ -211,21 +211,11 @@ class rust_language : public language_defn

/* See language.h. */

- const struct exp_descriptor *expression_ops () const override
- { return &exp_descriptor_tab; }
-
- /* See language.h. */
-
const struct op_print *opcode_print_table () const override
{ return c_op_print_tab; }

private:

- /* Table of expression handling functions for use by EXPRESSION_OPS
- member function. */
-
- static const struct exp_descriptor exp_descriptor_tab;
-
/* Helper for value_print_inner, arguments are as for that function.
Prints structs and untagged unions. */

--
2.26.2