[PATCH 075/203] Add two agent expression helper functions

Tom Tromey
2021-01-01T21:48:18Z

This adds a couple of agent expression helper functions that will be
useful when implementing various operations.

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

* expop.h (gen_expr_binop, gen_expr_structop): Declare.
* ax-gdb.c (gen_expr_binop): New function.
(gen_expr_structop): Likewise.
---
gdb/ChangeLog | 6 ++++++
gdb/ax-gdb.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
gdb/expop.h | 10 ++++++++++
3 files changed, 61 insertions(+)

diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c
index 728b21dfd6a..1ffa8e49bf1 100644
--- a/gdb/ax-gdb.c
+++ b/gdb/ax-gdb.c
@@ -158,6 +158,12 @@ static void gen_expr_binop_rest (struct expression *exp,
struct axs_value *value,
struct axs_value *value1,
struct axs_value *value2);
+static void gen_expr_binop_rest (struct expression *exp,
+ enum exp_opcode op,
+ struct agent_expr *ax,
+ struct axs_value *value,
+ struct axs_value *value1,
+ struct axs_value *value2);
\f

/* Detecting constant expressions. */
@@ -2458,6 +2464,45 @@ gen_expr_binop_rest (struct expression *exp,
gen_expr (exp, pc, ax, value2);
gen_expr_binop_rest (exp, op, ax, value, value1, value2);
}
+
+/* A helper function that emits a binop based on two operations. */
+
+void
+gen_expr_binop (struct expression *exp,
+ enum exp_opcode op,
+ expr::operation *lhs, expr::operation *rhs,
+ struct agent_expr *ax, struct axs_value *value)
+{
+ struct axs_value value1, value2;
+
+ lhs->generate_ax (exp, ax, &value1);
+ gen_usual_unary (ax, &value1);
+ rhs->generate_ax (exp, ax, &value2);
+ gen_expr_binop_rest (exp, op, ax, value, &value1, &value2);
+}
+
+/* A helper function that emits a structop based on an operation and a
+ member name. */
+
+void
+gen_expr_structop (struct expression *exp,
+ enum exp_opcode op,
+ expr::operation *lhs,
+ const char *name,
+ struct agent_expr *ax, struct axs_value *value)
+{
+ lhs->generate_ax (exp, ax, value);
+ if (op == STRUCTOP_STRUCT)
+ gen_struct_ref (ax, value, name, ".", "structure or union");
+ else if (op == STRUCTOP_PTR)
+ gen_struct_ref (ax, value, name, "->",
+ "pointer to a structure or union");
+ else
+ /* If this `if' chain doesn't handle it, then the case list
+ shouldn't mention it, and we shouldn't be here. */
+ internal_error (__FILE__, __LINE__,
+ _("gen_expr: unhandled struct case"));
+}
\f

/* Given a single variable and a scope, generate bytecodes to trace
diff --git a/gdb/expop.h b/gdb/expop.h
index 9fea1152cc9..2e7191cf59c 100644
--- a/gdb/expop.h
+++ b/gdb/expop.h
@@ -31,6 +31,16 @@
struct agent_expr;
struct axs_value;

+extern void gen_expr_binop (struct expression *exp,
+ enum exp_opcode op,
+ expr::operation *lhs, expr::operation *rhs,
+ struct agent_expr *ax, struct axs_value *value);
+extern void gen_expr_structop (struct expression *exp,
+ enum exp_opcode op,
+ expr::operation *lhs,
+ const char *name,
+ struct agent_expr *ax, struct axs_value *value);
+
namespace expr
{

--
2.26.2