[v3,118/206] Introduce assign_operation

Message ID 20210220201609.838264-119-tom@tromey.com
State New
Headers show
Series
  • Refactor expressions
Related show

Commit Message

Tom Tromey Feb. 20, 2021, 8:14 p.m.
This adds class assign_operation, which implements BINOP_ASSIGN.

gdb/ChangeLog
2021-02-20  Tom Tromey  <tom@tromey.com>

	* expop.h (class assign_operation): New.
	* ax-gdb.c (assign_operation::do_generate_ax): New method.
---
 gdb/ChangeLog |  5 +++++
 gdb/ax-gdb.c  | 30 ++++++++++++++++++++++++++++++
 gdb/expop.h   | 43 +++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 78 insertions(+)

-- 
2.26.2

Patch

diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c
index 98edc6c0727..d8b5ed78a40 100644
--- a/gdb/ax-gdb.c
+++ b/gdb/ax-gdb.c
@@ -2579,6 +2579,36 @@  op_this_operation::do_generate_ax (struct expression *exp,
 	   sym->print_name ());
 }
 
+void
+assign_operation::do_generate_ax (struct expression *exp,
+				  struct agent_expr *ax,
+				  struct axs_value *value,
+				  struct type *cast_type)
+{
+  operation *subop = std::get<0> (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;
+
+  std::get<1> (m_storage)->generate_ax (exp, ax, value);
+  tsv = find_trace_state_variable (name);
+  if (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/expop.h b/gdb/expop.h
index b196de52d0b..0f223654052 100644
--- a/gdb/expop.h
+++ b/gdb/expop.h
@@ -1757,6 +1757,49 @@  class type_instance_operation
   { return TYPE_INSTANCE; }
 };
 
+/* The assignment operator.  */
+class assign_operation
+  : public tuple_holding_operation<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<0> (m_storage)->evaluate (nullptr, exp, noside);
+    /* Special-case assignments where the left-hand-side is a
+       convenience variable -- in these, don't bother setting an
+       expected type.  This avoids a weird case where re-assigning a
+       string or array to an internal variable could error with "Too
+       many array elements".  */
+    struct type *xtype = (VALUE_LVAL (lhs) == lval_internalvar
+			  ? nullptr
+			  : value_type (lhs));
+    value *rhs = std::get<1> (m_storage)->evaluate (xtype, exp, noside);
+
+    if (noside == EVAL_SKIP || noside == EVAL_AVOID_SIDE_EFFECTS)
+      return lhs;
+    if (binop_user_defined_p (BINOP_ASSIGN, lhs, rhs))
+      return value_x_binop (lhs, rhs, BINOP_ASSIGN, OP_NULL, noside);
+    else
+      return value_assign (lhs, rhs);
+  }
+
+  enum exp_opcode opcode () const override
+  { return BINOP_ASSIGN; }
+
+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 */