compiler: Mark concurrent calls.

    
    If a call expression is executed in an independent goroutine via
    use of a Go statement, mark it as concurrent.
    
    Reviewed-on: https://go-review.googlesource.com/18700

From-SVN: r235608

gcc/go/gofrontend/MERGE

-b17e404f5b8954e008b512741296d238ab7b2ef9
+50b2b468a85045c66d60112dc094c31ec4897123
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

gcc/go/gofrontend/expressions.h

@@ -1985,8 +1985,8 @@ class Call_expression : public Expression
       fn_(fn), args_(args), type_(NULL), results_(NULL), call_(NULL),
       call_temp_(NULL), expected_result_count_(0), is_varargs_(is_varargs),
       varargs_are_lowered_(false), types_are_determined_(false),
-      is_deferred_(false), issued_error_(false), is_multi_value_arg_(false),
-      is_flattened_(false)
+      is_deferred_(false), is_concurrent_(false), issued_error_(false),
+      is_multi_value_arg_(false), is_flattened_(false)
   { }
 
   // The function to call.
@@ -2057,6 +2057,16 @@ class Call_expression : public Expression
   set_is_deferred()
   { this->is_deferred_ = true; }
 
+  // Whether this call is concurrently executed.
+  bool
+  is_concurrent() const
+  { return this->is_concurrent_; }
+
+  // Note that the call is concurrently executed.
+  void
+  set_is_concurrent()
+  { this->is_concurrent_ = true; }
+
   // We have found an error with this call expression; return true if
   // we should report it.
   bool
@@ -2170,6 +2180,8 @@ class Call_expression : public Expression
   bool types_are_determined_;
   // True if the call is an argument to a defer statement.
   bool is_deferred_;
+  // True if the call is an argument to a go statement.
+  bool is_concurrent_;
   // True if we reported an error about a mismatch between call
   // results and uses.  This is to avoid producing multiple errors
   // when there are multiple Call_result_expressions.

gcc/go/gofrontend/statements.cc

@@ -2532,7 +2532,9 @@ Thunk_statement::build_thunk(Gogo* gogo, const std::string& thunk_name)
 
   gogo->flatten_block(function, b);
 
-  if (may_call_recover || recover_arg != NULL)
+  if (may_call_recover
+      || recover_arg != NULL
+      || this->classification() == STATEMENT_GO)
     {
       // Dig up the call expression, which may have been changed
       // during lowering.
@@ -2546,6 +2548,8 @@ Thunk_statement::build_thunk(Gogo* gogo, const std::string& thunk_name)
 	{
 	  if (may_call_recover)
 	    ce->set_is_deferred();
+	  if (this->classification() == STATEMENT_GO)
+	    ce->set_is_concurrent();
 	  if (recover_arg != NULL)
 	    ce->set_recover_arg(recover_arg);
 	}