Go patch committed: Don't crash when using field tracking

Go patch committed: Don't crash when using field tracking

[Ian Lance Taylor]

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This patch to the Go compiler fixes a crash when using field tracking.
The code was failing to lower a function call added by the field
tracking code.  When called in a type equality function for a type
that was not otherwise used, this could cause a crash as the type was
never lowered.  This patch fixes that problem.  I also observed that
it's entirely unnecessary to add field tracking information for a
reference from a compiler generated equality function, so this patch
also avoids doing that, thus fixing the compiler crash in a different
way.  Bootstrapped and ran Go testsuite on x86_64-unknown-linux-gnu.
Committed to mainline.

Ian

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diff -r 5633f8241f0b go/expressions.cc
--- a/go/expressions.cc	Mon Dec 08 10:01:53 2014 -0800
+++ b/go/expressions.cc	Tue Dec 09 16:41:41 2014 -0800
@@ -10729,6 +10729,10 @@
   if (field->tag().find("go:\"track\"") == std::string::npos)
     return this;
 
+  // References from functions generated by the compiler don't count.
+  if (function->func_value()->is_type_specific_function())
+    return this;
+
   // We have found a reference to a tracked field.  Build a call to
   // the runtime function __go_fieldtrack with a string that describes
   // the field.  FIXME: We should only call this once per referenced
@@ -10785,6 +10789,7 @@
   e = Expression::make_unary(OPERATOR_AND, e, loc);
 
   Expression* call = Runtime::make_call(Runtime::FIELDTRACK, loc, 1, e);
+  gogo->lower_expression(function, inserter, &call);
   inserter->insert(Statement::make_statement(call, false));
 
   // Put this function, and the global variable we just created, into
diff -r 5633f8241f0b go/gogo.cc
--- a/go/gogo.cc	Mon Dec 08 10:01:53 2014 -0800
+++ b/go/gogo.cc	Tue Dec 09 16:41:41 2014 -0800
@@ -4433,6 +4433,7 @@
     is_sink_(false), results_are_named_(false), nointerface_(false),
     is_unnamed_type_stub_method_(false), calls_recover_(false),
     is_recover_thunk_(false), has_recover_thunk_(false),
+    calls_defer_retaddr_(false), is_type_specific_function_(false),
     in_unique_section_(false)
 {
 }
diff -r 5633f8241f0b go/gogo.h
--- a/go/gogo.h	Mon Dec 08 10:01:53 2014 -0800
+++ b/go/gogo.h	Tue Dec 09 16:41:41 2014 -0800
@@ -1071,6 +1071,18 @@
   set_calls_defer_retaddr()
   { this->calls_defer_retaddr_ = true; }
 
+  // Whether this is a type hash or equality function created by the
+  // compiler.
+  bool
+  is_type_specific_function()
+  { return this->is_type_specific_function_; }
+
+  // Record that this function is a type hash or equality function
+  // created by the compiler.
+  void
+  set_is_type_specific_function()
+  { this->is_type_specific_function_ = true; }
+
   // Mark the function as going into a unique section.
   void
   set_in_unique_section()
@@ -1199,6 +1211,9 @@
   // True if this is a thunk built for a defer statement that calls
   // the __go_set_defer_retaddr runtime function.
   bool calls_defer_retaddr_ : 1;
+  // True if this is a function built by the compiler to as a hash or
+  // equality function for some type.
+  bool is_type_specific_function_ : 1;
   // True if this function should be put in a unique section.  This is
   // turned on for field tracking.
   bool in_unique_section_ : 1;
diff -r 5633f8241f0b go/types.cc
--- a/go/types.cc	Mon Dec 08 10:01:53 2014 -0800
+++ b/go/types.cc	Tue Dec 09 16:41:41 2014 -0800
@@ -1805,6 +1805,7 @@
 
   Named_object* hash_fn = gogo->start_function(hash_name, hash_fntype, false,
 					       bloc);
+  hash_fn->func_value()->set_is_type_specific_function();
   gogo->start_block(bloc);
 
   if (name != NULL && name->real_type()->named_type() != NULL)
@@ -1825,6 +1826,7 @@
 
   Named_object *equal_fn = gogo->start_function(equal_name, equal_fntype,
 						false, bloc);
+  equal_fn->func_value()->set_is_type_specific_function();
   gogo->start_block(bloc);
 
   if (name != NULL && name->real_type()->named_type() != NULL)