[PATCH 104/203] Implement some unary operations

Tom Tromey
2021-01-01T21:48:44Z

This introduces a couple of new template classes and then uses them to
implement some simple unary operations.

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

* expop.h (unary_ftype): New typedef.
(unop_operation, usual_ax_binop_operation): New templates.
(unary_plus_operation, unary_neg_operation)
(unary_complement_operation, unary_logical_not_operation): New
typedefs.
* eval.c (eval_op_plus, eval_op_neg, eval_op_complement)
(eval_op_lognot): No longer static.
* ax-gdb.c (gen_expr_unop): New function.
---
gdb/ChangeLog | 11 ++++++++
gdb/ax-gdb.c | 47 +++++++++++++++++++++++++++++++
gdb/eval.c | 8 +++---
gdb/expop.h | 77 +++++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 139 insertions(+), 4 deletions(-)

diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c
index 8d5e4fff903..c87b290397d 100644
--- a/gdb/ax-gdb.c
+++ b/gdb/ax-gdb.c
@@ -2694,6 +2694,53 @@ gen_expr_structop (struct expression *exp,
internal_error (__FILE__, __LINE__,
_("gen_expr: unhandled struct case"));
}
+
+/* A helper function that emits a unary operation. */
+
+void
+gen_expr_unop (struct expression *exp,
+ enum exp_opcode op,
+ expr::operation *lhs,
+ struct agent_expr *ax, struct axs_value *value)
+{
+ struct axs_value value1, value2;
+
+ switch (op)
+ {
+ case UNOP_NEG:
+ gen_int_literal (ax, &value1, 0,
+ builtin_type (ax->gdbarch)->builtin_int);
+ gen_usual_unary (ax, &value1); /* shouldn't do much */
+ lhs->generate_ax (exp, ax, &value2);
+ gen_usual_unary (ax, &value2);
+ gen_usual_arithmetic (ax, &value1, &value2);
+ gen_binop (ax, value, &value1, &value2, aop_sub, aop_sub, 1, "negation");
+ break;
+
+ case UNOP_PLUS:
+ /* + FOO is equivalent to 0 + FOO, which can be optimized. */
+ lhs->generate_ax (exp, ax, value);
+ gen_usual_unary (ax, value);
+ break;
+
+ case UNOP_LOGICAL_NOT:
+ lhs->generate_ax (exp, ax, value);
+ gen_usual_unary (ax, value);
+ gen_logical_not (ax, value, builtin_type (ax->gdbarch)->builtin_int);
+ break;
+
+ case UNOP_COMPLEMENT:
+ lhs->generate_ax (exp, ax, value);
+ gen_usual_unary (ax, value);
+ gen_integral_promotions (ax, value);
+ gen_complement (ax, value);
+ break;
+
+ default:
+ gdb_assert_not_reached ("invalid case in gen_expr_unop");
+ }
+}
+
\f

/* Given a single variable and a scope, generate bytecodes to trace
diff --git a/gdb/eval.c b/gdb/eval.c
index 06f4c67e1d7..60e065cb0de 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -1739,7 +1739,7 @@ eval_op_repeat (struct type *expect_type, struct expression *exp,

/* A helper function for UNOP_PLUS. */

-static struct value *
+struct value *
eval_op_plus (struct type *expect_type, struct expression *exp,
enum noside noside, enum exp_opcode op,
struct value *arg1)
@@ -1757,7 +1757,7 @@ eval_op_plus (struct type *expect_type, struct expression *exp,

/* A helper function for UNOP_NEG. */

-static struct value *
+struct value *
eval_op_neg (struct type *expect_type, struct expression *exp,
enum noside noside, enum exp_opcode op,
struct value *arg1)
@@ -1775,7 +1775,7 @@ eval_op_neg (struct type *expect_type, struct expression *exp,

/* A helper function for UNOP_COMPLEMENT. */

-static struct value *
+struct value *
eval_op_complement (struct type *expect_type, struct expression *exp,
enum noside noside, enum exp_opcode op,
struct value *arg1)
@@ -1793,7 +1793,7 @@ eval_op_complement (struct type *expect_type, struct expression *exp,

/* A helper function for UNOP_LOGICAL_NOT. */

-static struct value *
+struct value *
eval_op_lognot (struct type *expect_type, struct expression *exp,
enum noside noside, enum exp_opcode op,
struct value *arg1)
diff --git a/gdb/expop.h b/gdb/expop.h
index 67b265ca8f0..aae42f201bc 100644
--- a/gdb/expop.h
+++ b/gdb/expop.h
@@ -40,6 +40,10 @@ extern void gen_expr_structop (struct expression *exp,
expr::operation *lhs,
const char *name,
struct agent_expr *ax, struct axs_value *value);
+extern void gen_expr_unop (struct expression *exp,
+ enum exp_opcode op,
+ expr::operation *lhs,
+ struct agent_expr *ax, struct axs_value *value);

extern struct value *eval_op_scope (struct type *expect_type,
struct expression *exp,
@@ -139,6 +143,24 @@ extern struct value *eval_op_repeat (struct type *expect_type,
enum noside noside, enum exp_opcode op,
struct value *arg1,
struct value *arg2);
+extern struct value *eval_op_plus (struct type *expect_type,
+ struct expression *exp,
+ enum noside noside, enum exp_opcode op,
+ struct value *arg1);
+extern struct value *eval_op_neg (struct type *expect_type,
+ struct expression *exp,
+ enum noside noside, enum exp_opcode op,
+ struct value *arg1);
+extern struct value *eval_op_complement (struct type *expect_type,
+ struct expression *exp,
+ enum noside noside,
+ enum exp_opcode op,
+ struct value *arg1);
+extern struct value *eval_op_lognot (struct type *expect_type,
+ struct expression *exp,
+ enum noside noside,
+ enum exp_opcode op,
+ struct value *arg1);

namespace expr
{
@@ -1228,6 +1250,61 @@ class comma_operation
override;
};

+typedef struct value *unary_ftype (struct type *expect_type,
+ struct expression *exp,
+ enum noside noside, enum exp_opcode op,
+ struct value *arg1);
+
+/* Base class for unary operations. */
+template<enum exp_opcode OP, unary_ftype FUNC>
+class unop_operation
+ : public maybe_constant_operation<operation_up>
+{
+public:
+
+ using maybe_constant_operation::maybe_constant_operation;
+
+ value *evaluate (struct type *expect_type,
+ struct expression *exp,
+ enum noside noside) override
+ {
+ value *val = std::get<0> (m_storage)->evaluate (nullptr, exp, noside);
+ return FUNC (expect_type, exp, noside, OP, val);
+ }
+
+ enum exp_opcode opcode () const override
+ { return OP; }
+};
+
+/* Unary operations that can also be turned into agent expressions in
+ the "usual" way. */
+template<enum exp_opcode OP, unary_ftype FUNC>
+class usual_ax_unop_operation
+ : public unop_operation<OP, FUNC>
+{
+ using unop_operation<OP, FUNC>::unop_operation;
+
+protected:
+
+ void do_generate_ax (struct expression *exp,
+ struct agent_expr *ax,
+ struct axs_value *value,
+ struct type *cast_type)
+ override
+ {
+ gen_expr_unop (exp, OP,
+ std::get<0> (this->m_storage).get (),
+ ax, value);
+ }
+};
+
+using unary_plus_operation = usual_ax_unop_operation<UNOP_PLUS, eval_op_plus>;
+using unary_neg_operation = usual_ax_unop_operation<UNOP_NEG, eval_op_neg>;
+using unary_complement_operation
+ = usual_ax_unop_operation<UNOP_COMPLEMENT, eval_op_complement>;
+using unary_logical_not_operation
+ = usual_ax_unop_operation<UNOP_LOGICAL_NOT, eval_op_lognot>;
+
} /* namespace expr */

#endif /* EXPOP_H */
--
2.26.2