From 260f587c3a51252440b07eeaa4794bcb98332c72 Mon Sep 17 00:00:00 2001
From: Ian Lance Taylor <ian@gcc.gnu.org>
Date: Fri, 1 Feb 2013 00:23:22 +0000
Subject: [PATCH] compiler: Don't emit multiple methods for identical unnamed
structs.
From-SVN: r195638
---
gcc/go/gofrontend/types.cc | 20 ++++++++++++++++++++
gcc/go/gofrontend/types.h | 6 ++++++
2 files changed, 26 insertions(+)
diff --git a/gcc/go/gofrontend/types.cc b/gcc/go/gofrontend/types.cc
index c0aeb91acff1..769498282290 100644
--- a/gcc/go/gofrontend/types.cc
+++ b/gcc/go/gofrontend/types.cc
@@ -4170,6 +4170,11 @@ Struct_field::is_field_name(const std::string& name) const
// Class Struct_type.
+// A hash table used to find identical unnamed structs so that they
+// share method tables.
+
+Struct_type::Identical_structs Struct_type::identical_structs;
+
// Traversal.
int
@@ -4596,6 +4601,21 @@ Struct_type::finalize_methods(Gogo* gogo)
{
if (this->all_methods_ != NULL)
return;
+
+ // It is possible to have multiple identical structs that have
+ // methods. We want them to share method tables. Otherwise we will
+ // emit identical methods more than once, which is bad since they
+ // will even have the same names.
+ std::pair<Identical_structs::iterator, bool> ins =
+ Struct_type::identical_structs.insert(std::make_pair(this, this));
+ if (!ins.second)
+ {
+ // An identical struct was already entered into the hash table.
+ // Note that finalize_methods is, fortunately, not recursive.
+ this->all_methods_ = ins.first->second->all_methods_;
+ return;
+ }
+
Type::finalize_methods(gogo, this, this->location_, &this->all_methods_);
}
diff --git a/gcc/go/gofrontend/types.h b/gcc/go/gofrontend/types.h
index ba918c960239..3922a634f592 100644
--- a/gcc/go/gofrontend/types.h
+++ b/gcc/go/gofrontend/types.h
@@ -2184,6 +2184,12 @@ class Struct_type : public Type
do_export(Export*) const;
private:
+ // Used to merge method sets of identical unnamed structs.
+ typedef Unordered_map_hash(Struct_type*, Struct_type*, Type_hash_identical,
+ Type_identical) Identical_structs;
+
+ static Identical_structs identical_structs;
+
// Used to avoid infinite loops in field_reference_depth.
struct Saw_named_type
{
--
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