[104/203] Implement some unary operations

Message ID 20210101214723.1784144-105-tom@tromey.com
State Superseded
Headers show
Series
  • Refactor expressions
Related show

Commit Message

Tom Tromey Jan. 1, 2021, 9:45 p.m.
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(-)

-- 
2.26.2

Patch

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");
+    }
+}
+
 
 
 /* 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 */