[PATCH 118/203] Introduce assign_modify_operation

Tom Tromey
2021-01-01T21:48:54Z

This adds class assign_modify_operation, which implements
BINOP_ASSIGN_MODIFY.

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

* expop.h (class assign_modify_operation): New.
* eval.c (eval_binop_assign_modify): No longer static.
* ax-gdb.c (assign_modify_operation::do_generate_ax): New method.
---
gdb/ChangeLog | 6 ++++++
gdb/ax-gdb.c | 42 ++++++++++++++++++++++++++++++++++++++++++
gdb/eval.c | 2 +-
gdb/expop.h | 36 ++++++++++++++++++++++++++++++++++++
4 files changed, 85 insertions(+), 1 deletion(-)

diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c
index d8b5ed78a40..f81e5b9ad29 100644
--- a/gdb/ax-gdb.c
+++ b/gdb/ax-gdb.c
@@ -2609,6 +2609,48 @@ assign_operation::do_generate_ax (struct expression *exp,
"may not assign to it"), name);
}

+void
+assign_modify_operation::do_generate_ax (struct expression *exp,
+ struct agent_expr *ax,
+ struct axs_value *value,
+ struct type *cast_type)
+{
+ operation *subop = std::get<1> (m_storage).get ();
+ if (subop->opcode () != OP_INTERNALVAR)
+ error (_("May only assign to trace state variables"));
+
+ internalvar_operation *ivarop
+ = dynamic_cast<internalvar_operation *> (subop);
+ gdb_assert (ivarop != nullptr);
+
+ const char *name = internalvar_name (ivarop->get_internalvar ());
+ struct trace_state_variable *tsv;
+
+ tsv = find_trace_state_variable (name);
+ if (tsv)
+ {
+ /* The tsv will be the left half of the binary operation. */
+ ax_tsv (ax, aop_getv, tsv->number);
+ if (ax->tracing)
+ ax_tsv (ax, aop_tracev, tsv->number);
+ /* Trace state variables are always 64-bit integers. */
+ struct axs_value value1, value2;
+ value1.kind = axs_rvalue;
+ value1.type = builtin_type (ax->gdbarch)->builtin_long_long;
+ /* Now do right half of expression. */
+ std::get<2> (m_storage)->generate_ax (exp, ax, &value2);
+ gen_expr_binop_rest (exp, std::get<0> (m_storage), ax,
+ value, &value1, &value2);
+ /* We have a result of the binary op, set the tsv. */
+ ax_tsv (ax, aop_setv, tsv->number);
+ if (ax->tracing)
+ ax_tsv (ax, aop_tracev, tsv->number);
+ }
+ else
+ error (_("$%s is not a trace state variable, "
+ "may not assign to it"), name);
+}
+
}

/* This handles the middle-to-right-side of code generation for binary
diff --git a/gdb/eval.c b/gdb/eval.c
index 65214a2bd3a..51a737ac5a5 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -2049,7 +2049,7 @@ eval_op_type (struct type *expect_type, struct expression *exp,

/* A helper function for BINOP_ASSIGN_MODIFY. */

-static struct value *
+struct value *
eval_binop_assign_modify (struct type *expect_type, struct expression *exp,
enum noside noside, enum exp_opcode op,
struct value *arg1, struct value *arg2)
diff --git a/gdb/expop.h b/gdb/expop.h
index 5acbca3db61..b0ed119a989 100644
--- a/gdb/expop.h
+++ b/gdb/expop.h
@@ -196,6 +196,12 @@ extern struct value *eval_op_memval (struct type *expect_type,
struct expression *exp,
enum noside noside,
struct value *arg1, struct type *type);
+extern struct value *eval_binop_assign_modify (struct type *expect_type,
+ struct expression *exp,
+ enum noside noside,
+ enum exp_opcode op,
+ struct value *arg1,
+ struct value *arg2);

namespace expr
{
@@ -1789,6 +1795,36 @@ class assign_operation
override;
};

+/* Assignment with modification, like "+=". */
+class assign_modify_operation
+ : public tuple_holding_operation<exp_opcode, operation_up, operation_up>
+{
+public:
+
+ using tuple_holding_operation::tuple_holding_operation;
+
+ value *evaluate (struct type *expect_type,
+ struct expression *exp,
+ enum noside noside) override
+ {
+ value *lhs = std::get<1> (m_storage)->evaluate (nullptr, exp, noside);
+ value *rhs = std::get<2> (m_storage)->evaluate (expect_type, exp, noside);
+ return eval_binop_assign_modify (expect_type, exp, noside,
+ std::get<0> (m_storage), lhs, rhs);
+ }
+
+ enum exp_opcode opcode () const override
+ { return BINOP_ASSIGN_MODIFY; }
+
+protected:
+
+ void do_generate_ax (struct expression *exp,
+ struct agent_expr *ax,
+ struct axs_value *value,
+ struct type *cast_type)
+ override;
+};
+
} /* namespace expr */

#endif /* EXPOP_H */
--
2.26.2