This patch to the Go compiler fixes a crash when using go or defer with
some builtin functions, namely those that have no side-effects.
Bootstrapped and ran Go testsuite on x86_64-unknown-linux-gnu.
Committed to mainline and 4.7 branch.
Ian
diff -r 952fc7825cfa go/expressions.cc
--- a/go/expressions.cc Mon Dec 03 16:27:21 2012 -0800
+++ b/go/expressions.cc Mon Dec 03 20:57:51 2012 -0800
@@ -80,10 +80,11 @@
// expression is being discarded. By default, we give an error.
// Expressions with side effects override.
-void
+bool
Expression::do_discarding_value()
{
this->unused_value_error();
+ return false;
}
// This virtual function is called to export expressions. This will
@@ -100,7 +101,7 @@
void
Expression::unused_value_error()
{
- error_at(this->location(), "value computed is not used");
+ this->report_error(_("value computed is not used"));
}
// Note that this expression is an error. This is called by children
@@ -786,9 +787,9 @@
return true;
}
- void
+ bool
do_discarding_value()
- { }
+ { return true; }
Type*
do_type()
@@ -1149,9 +1150,9 @@
{ }
protected:
- void
+ bool
do_discarding_value()
- { }
+ { return true; }
Type*
do_type();
@@ -5326,13 +5327,19 @@
// Note that the value is being discarded.
-void
+bool
Binary_expression::do_discarding_value()
{
if (this->op_ == OPERATOR_OROR || this->op_ == OPERATOR_ANDAND)
- this->right_->discarding_value();
- else
- this->unused_value_error();
+ {
+ this->right_->discarding_value();
+ return true;
+ }
+ else
+ {
+ this->unused_value_error();
+ return false;
+ }
}
// Get type.
@@ -6536,7 +6543,7 @@
bool
do_numeric_constant_value(Numeric_constant*) const;
- void
+ bool
do_discarding_value();
Type*
@@ -7338,7 +7345,7 @@
// discarding the value of an ordinary function call, but we do for
// builtin functions, purely for consistency with the gc compiler.
-void
+bool
Builtin_call_expression::do_discarding_value()
{
switch (this->code_)
@@ -7359,7 +7366,7 @@
case BUILTIN_OFFSETOF:
case BUILTIN_SIZEOF:
this->unused_value_error();
- break;
+ return false;
case BUILTIN_CLOSE:
case BUILTIN_COPY:
@@ -7368,7 +7375,7 @@
case BUILTIN_PRINT:
case BUILTIN_PRINTLN:
case BUILTIN_RECOVER:
- break;
+ return true;
}
}
diff -r 952fc7825cfa go/expressions.h
--- a/go/expressions.h Mon Dec 03 16:27:21 2012 -0800
+++ b/go/expressions.h Mon Dec 03 20:57:51 2012 -0800
@@ -360,10 +360,11 @@
// This is called if the value of this expression is being
// discarded. This issues warnings about computed values being
- // unused.
- void
+ // unused. This returns true if all is well, false if it issued an
+ // error message.
+ bool
discarding_value()
- { this->do_discarding_value(); }
+ { return this->do_discarding_value(); }
// Return whether this is an error expression.
bool
@@ -689,7 +690,7 @@
{ return false; }
// Called by the parser if the value is being discarded.
- virtual void
+ virtual bool
do_discarding_value();
// Child class holds type.
@@ -1205,7 +1206,7 @@
bool
do_numeric_constant_value(Numeric_constant*) const;
- void
+ bool
do_discarding_value();
Type*
@@ -1373,9 +1374,9 @@
virtual Expression*
do_lower(Gogo*, Named_object*, Statement_inserter*, int);
- void
+ bool
do_discarding_value()
- { }
+ { return true; }
virtual Type*
do_type();
@@ -2056,9 +2057,9 @@
do_traverse(Traverse* traverse)
{ return Expression::traverse(&this->channel_, traverse); }
- void
+ bool
do_discarding_value()
- { }
+ { return true; }
Type*
do_type();
diff -r 952fc7825cfa go/statements.cc
--- a/go/statements.cc Mon Dec 03 16:27:21 2012 -0800
+++ b/go/statements.cc Mon Dec 03 20:57:51 2012 -0800
@@ -2006,6 +2006,8 @@
void
Thunk_statement::do_check_types(Gogo*)
{
+ if (!this->call_->discarding_value())
+ return;
Call_expression* ce = this->call_->call_expression();
if (ce == NULL)
{
@@ -2471,11 +2473,15 @@
Expression_statement* es =
static_cast<Expression_statement*>(call_statement);
Call_expression* ce = es->expr()->call_expression();
- go_assert(ce != NULL);
- if (may_call_recover)
- ce->set_is_deferred();
- if (recover_arg != NULL)
- ce->set_recover_arg(recover_arg);
+ if (ce == NULL)
+ go_assert(saw_errors());
+ else
+ {
+ if (may_call_recover)
+ ce->set_is_deferred();
+ if (recover_arg != NULL)
+ ce->set_recover_arg(recover_arg);
+ }
}
// That is all the thunk has to do.
