compiler: update iota handling, fix using iota in array length

    
    CL 71750 changed the definition of how iota works.  This patch updates
    gccgo for the new definition.
    
    We've been mishandling iota appearing in a type that appears in a
    const expression, as in `c = len([iota]int{})`.  Correct that by copying
    type expressions when we copy an expression.  For simplicity only copy
    when it can change the size of a type, as that is the only case where
    iota in a type can affect the value of a constant (I think).  This is
    still a bunch of changes, but almost all boilerplate.
    
    Fixes golang/go#22341
    
    Reviewed-on: https://go-review.googlesource.com/91475

From-SVN: r257379

1 files changed, 7 insertions, 33 deletions

diff --git a/gcc/go/gofrontend/parse.cc b/gcc/go/gofrontend/parse.cc
index cc3791b..4891e75 100644
--- a/gcc/go/gofrontend/parse.cc
+++ b/gcc/go/gofrontend/parse.cc
@@ -50,7 +50,6 @@ Parse::Parse(Lex* lex, Gogo* gogo)
     gogo_(gogo),
     break_stack_(NULL),
     continue_stack_(NULL),
-    iota_(0),
     enclosing_vars_()
 {
 }
@@ -1407,19 +1406,20 @@ Parse::const_decl()
 {
   go_assert(this->peek_token()->is_keyword(KEYWORD_CONST));
   this->advance_token();
-  this->reset_iota();
 
+  int iota = 0;
   Type* last_type = NULL;
   Expression_list* last_expr_list = NULL;
 
   if (!this->peek_token()->is_op(OPERATOR_LPAREN))
-    this->const_spec(&last_type, &last_expr_list);
+    this->const_spec(iota, &last_type, &last_expr_list);
   else
     {
       this->advance_token();
       while (!this->peek_token()->is_op(OPERATOR_RPAREN))
 	{
-	  this->const_spec(&last_type, &last_expr_list);
+	  this->const_spec(iota, &last_type, &last_expr_list);
+	  ++iota;
 	  if (this->peek_token()->is_op(OPERATOR_SEMICOLON))
 	    this->advance_token();
 	  else if (!this->peek_token()->is_op(OPERATOR_RPAREN))
@@ -1440,7 +1440,7 @@ Parse::const_decl()
 // ConstSpec = IdentifierList [ [ CompleteType ] "=" ExpressionList ] .
 
 void
-Parse::const_spec(Type** last_type, Expression_list** last_expr_list)
+Parse::const_spec(int iota, Type** last_type, Expression_list** last_expr_list)
 {
   Typed_identifier_list til;
   this->identifier_list(&til);
@@ -1492,7 +1492,7 @@ Parse::const_spec(Type** last_type, Expression_list** last_expr_list)
 	pi->set_type(type);
 
       if (!Gogo::is_sink_name(pi->name()))
-	this->gogo_->add_constant(*pi, *pe, this->iota_value());
+	this->gogo_->add_constant(*pi, *pe, iota);
       else
 	{
 	  static int count;
@@ -1500,15 +1500,13 @@ Parse::const_spec(Type** last_type, Expression_list** last_expr_list)
 	  snprintf(buf, sizeof buf, ".$sinkconst%d", count);
 	  ++count;
 	  Typed_identifier ti(std::string(buf), type, pi->location());
-	  Named_object* no = this->gogo_->add_constant(ti, *pe, this->iota_value());
+	  Named_object* no = this->gogo_->add_constant(ti, *pe, iota);
 	  no->const_value()->set_is_sink();
 	}
     }
   if (pe != expr_list->end())
     go_error_at(this->location(), "too many initializers");
 
-  this->increment_iota();
-
   return;
 }
 
@@ -5838,30 +5836,6 @@ Parse::program()
     }
 }
 
-// Reset the current iota value.
-
-void
-Parse::reset_iota()
-{
-  this->iota_ = 0;
-}
-
-// Return the current iota value.
-
-int
-Parse::iota_value()
-{
-  return this->iota_;
-}
-
-// Increment the current iota value.
-
-void
-Parse::increment_iota()
-{
-  ++this->iota_;
-}
-
 // Skip forward to a semicolon or OP.  OP will normally be
 // OPERATOR_RPAREN or OPERATOR_RCURLY.  If we find a semicolon, move
 // past it and return.  If we find OP, it will be the next token to