This patch by Chris Manghane changes the Go frontend to track each
package import separately, so that we can report whether an import is
used separately by the alias used. This fixes
https://golang.org/issue/12326 . This requires adjust a couple of
test cases, to match errors previously only emitted by the gc
compiler, now also emitted by gccgo. Bootstrapped and ran Go
testsuite on x86_64-unknown-linux-gnu. Committed to mainline.
Ian
Index: gcc/go/gofrontend/MERGE
===================================================================
--- gcc/go/gofrontend/MERGE (revision 228497)
+++ gcc/go/gofrontend/MERGE (working copy)
@@ -1,4 +1,4 @@
-d8150af96de991fb79b1bf65ae982a860552c492
+3039d79149901d25d89c2412bdd8684f3cbcd09e
The first line of this file holds the git revision number of the last
merge done from the gofrontend repository.
Index: gcc/go/gofrontend/gogo.cc
===================================================================
--- gcc/go/gofrontend/gogo.cc (revision 228306)
+++ gcc/go/gofrontend/gogo.cc (working copy)
@@ -516,7 +516,6 @@ Gogo::import_package(const std::string&
{
Package* package = p->second;
package->set_location(location);
- package->set_is_imported();
std::string ln = local_name;
bool is_ln_exported = is_local_name_exported;
if (ln.empty())
@@ -525,7 +524,9 @@ Gogo::import_package(const std::string&
go_assert(!ln.empty());
is_ln_exported = Lex::is_exported_name(ln);
}
- if (ln == ".")
+ if (ln == "_")
+ ;
+ else if (ln == ".")
{
Bindings* bindings = package->bindings();
for (Bindings::const_declarations_iterator p =
@@ -533,11 +534,12 @@ Gogo::import_package(const std::string&
p != bindings->end_declarations();
++p)
this->add_dot_import_object(p->second);
+ std::string dot_alias = "." + package->package_name();
+ package->add_alias(dot_alias, location);
}
- else if (ln == "_")
- package->set_uses_sink_alias();
else
{
+ package->add_alias(ln, location);
ln = this->pack_hidden_name(ln, is_ln_exported);
this->package_->bindings()->add_package(ln, package);
}
@@ -563,7 +565,6 @@ Gogo::import_package(const std::string&
"being compiled (see -fgo-pkgpath option)"));
this->imports_.insert(std::make_pair(filename, package));
- package->set_is_imported();
}
delete stream;
@@ -1544,7 +1545,10 @@ Gogo::lookup(const std::string& name, Na
if (ret != NULL)
{
if (ret->package() != NULL)
- ret->package()->note_usage();
+ {
+ std::string dot_alias = "." + ret->package()->package_name();
+ ret->package()->note_usage(dot_alias);
+ }
return ret;
}
}
@@ -1594,10 +1598,14 @@ Gogo::add_imported_package(const std::st
*padd_to_globals = false;
- if (alias_arg == ".")
- *padd_to_globals = true;
- else if (alias_arg == "_")
- ret->set_uses_sink_alias();
+ if (alias_arg == "_")
+ ;
+ else if (alias_arg == ".")
+ {
+ *padd_to_globals = true;
+ std::string dot_alias = "." + real_name;
+ ret->add_alias(dot_alias, location);
+ }
else
{
std::string alias = alias_arg;
@@ -1606,6 +1614,7 @@ Gogo::add_imported_package(const std::st
alias = real_name;
is_alias_exported = Lex::is_exported_name(alias);
}
+ ret->add_alias(alias, location);
alias = this->pack_hidden_name(alias, is_alias_exported);
Named_object* no = this->package_->bindings()->add_package(alias, ret);
if (!no->is_package())
@@ -2356,15 +2365,30 @@ Gogo::clear_file_scope()
++p)
{
Package* package = p->second;
- if (package != this->package_
- && package->is_imported()
- && !package->used()
- && !package->uses_sink_alias()
- && !quiet)
- error_at(package->location(), "imported and not used: %s",
- Gogo::message_name(package->package_name()).c_str());
- package->clear_is_imported();
- package->clear_uses_sink_alias();
+ if (package != this->package_ && !quiet)
+ {
+ for (Package::Aliases::const_iterator p1 =
package->aliases().begin();
+ p1 != package->aliases().end();
+ ++p1)
+ {
+ if (!p1->second->used())
+ {
+ // Give a more refined error message if the alias name is
known.
+ std::string pkg_name = package->package_name();
+ if (p1->first != pkg_name && p1->first[0] != '.')
+ {
+ error_at(p1->second->location(),
+ "imported and not used: %s as %s",
+ Gogo::message_name(pkg_name).c_str(),
+ Gogo::message_name(p1->first).c_str());
+ }
+ else
+ error_at(p1->second->location(),
+ "imported and not used: %s",
+ Gogo::message_name(pkg_name).c_str());
+ }
+ }
+ }
package->clear_used();
}
}
@@ -7741,8 +7765,7 @@ Package::Package(const std::string& pkgp
const std::string& pkgpath_symbol, Location location)
: pkgpath_(pkgpath), pkgpath_symbol_(pkgpath_symbol),
package_name_(), bindings_(new Bindings(NULL)), priority_(0),
- location_(location), used_(false), is_imported_(false),
- uses_sink_alias_(false)
+ location_(location)
{
go_assert(!pkgpath.empty());
@@ -7796,6 +7819,16 @@ Package::set_priority(int priority)
this->priority_ = priority;
}
+// Note that symbol from this package was and qualified by ALIAS.
+
+void
+Package::note_usage(const std::string& alias) const
+{
+ Aliases::const_iterator p = this->aliases_.find(alias);
+ go_assert(p != this->aliases_.end());
+ p->second->note_usage();
+}
+
// Forget a given usage. If forgetting this usage means this package becomes
// unused, report that error.
@@ -7811,7 +7844,7 @@ Package::forget_usage(Expression* usage)
if (this->fake_uses_.empty())
error_at(this->location(), "imported and not used: %s",
- Gogo::message_name(this->package_name()).c_str());
+ Gogo::message_name(this->package_name()).c_str());
}
// Clear the used field for the next file. If the only usages of this package
@@ -7820,10 +7853,26 @@ Package::forget_usage(Expression* usage)
void
Package::clear_used()
{
- if (this->used_ > this->fake_uses_.size())
+ std::string dot_alias = "." + this->package_name();
+ Aliases::const_iterator p = this->aliases_.find(dot_alias);
+ if (p != this->aliases_.end() && p->second->used() > this->fake_uses_.size())
this->fake_uses_.clear();
- this->used_ = 0;
+ this->aliases_.clear();
+}
+
+Package_alias*
+Package::add_alias(const std::string& alias, Location location)
+{
+ Aliases::const_iterator p = this->aliases_.find(alias);
+ if (p == this->aliases_.end())
+ {
+ std::pair<Aliases::iterator, bool> ret;
+ ret = this->aliases_.insert(std::make_pair(alias,
+ new Package_alias(location)));
+ p = ret.first;
+ }
+ return p->second;
}
// Determine types of constants. Everything else in a package
Index: gcc/go/gofrontend/gogo.h
===================================================================
--- gcc/go/gofrontend/gogo.h (revision 228306)
+++ gcc/go/gofrontend/gogo.h (working copy)
@@ -2771,6 +2771,37 @@ class Unnamed_label
Blabel* blabel_;
};
+// An alias for an imported package.
+
+class Package_alias
+{
+ public:
+ Package_alias(Location location)
+ : location_(location), used_(0)
+ { }
+
+ // The location of the import statement.
+ Location
+ location()
+ { return this->location_; }
+
+ // How many symbols from the package were used under this alias.
+ size_t
+ used() const
+ { return this->used_; }
+
+ // Note that some symbol was used under this alias.
+ void
+ note_usage()
+ { this->used_++; }
+
+ private:
+ // The location of the import statement.
+ Location location_;
+ // The amount of times some name from this package was used under this alias.
+ size_t used_;
+};
+
// An imported package.
class Package
@@ -2793,7 +2824,7 @@ class Package
void
set_pkgpath_symbol(const std::string&);
- // Return the location of the import statement.
+ // Return the location of the most recent import statement.
Location
location() const
{ return this->location_; }
@@ -2829,15 +2860,18 @@ class Package
bindings()
{ return this->bindings_; }
- // Whether some symbol from the package was used.
- bool
- used() const
- { return this->used_ > 0; }
+ // Type used to map import names to package aliases.
+ typedef std::map<std::string, Package_alias*> Aliases;
+
+ // Return the set of package aliases.
+ const Aliases&
+ aliases() const
+ { return this->aliases_; }
- // Note that some symbol from this package was used.
+ // Note that some symbol from this package was used and qualified by ALIAS.
+ // For dot imports, the ALIAS should be ".PACKAGE_NAME".
void
- note_usage() const
- { this->used_++; }
+ note_usage(const std::string& alias) const;
// Note that USAGE might be a fake usage of this package.
void
@@ -2852,36 +2886,6 @@ class Package
void
clear_used();
- // Whether this package was imported in the current file.
- bool
- is_imported() const
- { return this->is_imported_; }
-
- // Note that this package was imported in the current file.
- void
- set_is_imported()
- { this->is_imported_ = true; }
-
- // Clear the imported field for the next file.
- void
- clear_is_imported()
- { this->is_imported_ = false; }
-
- // Whether this package was imported with a name of "_".
- bool
- uses_sink_alias() const
- { return this->uses_sink_alias_; }
-
- // Note that this package was imported with a name of "_".
- void
- set_uses_sink_alias()
- { this->uses_sink_alias_ = true; }
-
- // Clear the sink alias field for the next file.
- void
- clear_uses_sink_alias()
- { this->uses_sink_alias_ = false; }
-
// Look up a name in the package. Returns NULL if the name is not
// found.
Named_object*
@@ -2898,6 +2902,10 @@ class Package
set_location(Location location)
{ this->location_ = location; }
+ // Add a package name as an ALIAS for this package.
+ Package_alias*
+ add_alias(const std::string& alias, Location);
+
// Add a constant to the package.
Named_object*
add_constant(const Typed_identifier& tid, Expression* expr)
@@ -2942,18 +2950,13 @@ class Package
// than the priority of all of the packages that it imports. This
// is used to run init functions in the right order.
int priority_;
- // The location of the import statement.
+ // The location of the most recent import statement.
Location location_;
- // The amount of times some name from this package was used. This is mutable
- // because we can use a package even if we have a const pointer to it.
- mutable size_t used_;
- // A set of possibly fake uses of this package. This is mutable because we
+ // The set of aliases associated with this package.
+ Aliases aliases_;
+ // A set of possibly fake uses of this package. This is mutable because we
// can track fake uses of a package even if we have a const pointer to it.
mutable std::set<Expression*> fake_uses_;
- // True if this package was imported in the current file.
- bool is_imported_;
- // True if this package was imported with a name of "_".
- bool uses_sink_alias_;
};
// Return codes for the traversal functions. This is not an enum
Index: gcc/go/gofrontend/parse.cc
===================================================================
--- gcc/go/gofrontend/parse.cc (revision 228306)
+++ gcc/go/gofrontend/parse.cc (working copy)
@@ -198,7 +198,7 @@ Parse::qualified_ident(std::string* pnam
return false;
}
- package->package_value()->note_usage();
+ package->package_value()->note_usage(Gogo::unpack_hidden_name(name));
token = this->advance_token();
if (!token->is_identifier())
@@ -2430,7 +2430,7 @@ Parse::operand(bool may_be_sink, bool* i
return Expression::make_error(location);
}
package = named_object->package_value();
- package->note_usage();
+ package->note_usage(id);
id = this->peek_token()->identifier();
is_exported = this->peek_token()->is_identifier_exported();
packed = this->gogo_->pack_hidden_name(id, is_exported);
Index: gcc/go/gofrontend/unsafe.cc
===================================================================
--- gcc/go/gofrontend/unsafe.cc (revision 228306)
+++ gcc/go/gofrontend/unsafe.cc (working copy)
@@ -32,8 +32,6 @@ Gogo::import_unsafe(const std::string& l
}
package->set_location(location);
- package->set_is_imported();
-
this->imports_.insert(std::make_pair("unsafe", package));
Bindings* bindings = package->bindings();
Index: gcc/testsuite/go.test/test/fixedbugs/issue5957.dir/c.go
===================================================================
--- gcc/testsuite/go.test/test/fixedbugs/issue5957.dir/c.go (revision
228306)
+++ gcc/testsuite/go.test/test/fixedbugs/issue5957.dir/c.go (working copy)
@@ -2,7 +2,7 @@ package p
import (
"./a" // ERROR "imported and not used: \x22a\x22 as surprise|imported
and not used: surprise"
- "./b" // GC_ERROR "imported and not used: \x22b\x22 as
surprise2|imported and not used: surprise2"
+ "./b" // ERROR "imported and not used: \x22b\x22 as surprise2|imported
and not used: surprise2"
b "./b" // ERROR "imported and not used: \x22b\x22$|imported and not
used: surprise2"
foo "math" // ERROR "imported and not used: \x22math\x22 as
foo|imported and not used: math"
"fmt" // actually used
Index: gcc/testsuite/go.test/test/import4.dir/import4.go
===================================================================
--- gcc/testsuite/go.test/test/import4.dir/import4.go (revision 228306)
+++ gcc/testsuite/go.test/test/import4.dir/import4.go (working copy)
@@ -18,7 +18,7 @@ import X "math" // ERROR "imported and n
import . "bufio" // ERROR "imported and not used.*bufio"
// again, package without anything in it
-import "./empty" // GC_ERROR "imported and not used.*empty"
-import Z "./empty" // GC_ERROR "imported and not used.*empty"
+import "./empty" // ERROR "imported and not used.*empty"
+import Z "./empty" // ERROR "imported and not used.*empty"
import . "./empty" // ERROR "imported and not used.*empty"
