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riscv-gcc-1
Commit f4a513a9 by Ian Lance Taylor
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compiler, reflect, runtime: remove zero field from type descriptor 

    
    Type descriptors picked up a zero field because the gc map
    implementation used it.  However, it's since been dropped by the gc
    library.  It was never used by gccgo.  Drop it now in preparation for
    upgrading to the Go 1.5 library.
    
    Reviewed-on: https://go-review.googlesource.com/16486

From-SVN: r229546
parent bdb60a10
Showing with 7 additions and 143 deletions
gcc/go/gofrontend/MERGE
57da43e8159bfe1a31e49683c371cf36e2fb6051
85994dd0a88d1b24b2ddfc9c9ab22ee16c9e8b54
The first line of this file holds the git revision number of the last
merge done from the gofrontend repository.
gcc/go/gofrontend/gogo.cc
......@@ -42,9 +42,6 @@ Gogo::Gogo(Backend* backend, Linemap* linemap, int, int pointer_size)
pkgpath_(),
pkgpath_symbol_(),
prefix_(),
zero_value_(NULL),
zero_value_size_(0),
zero_value_align_(0),
pkgpath_set_(false),
pkgpath_from_option_(false),
prefix_from_option_(false),
......@@ -638,87 +635,6 @@ Gogo::current_bindings() const
return this->globals_;
}
// Return the special variable used as the zero value of types.
Named_object*
Gogo::zero_value(Type *type)
{
if (this->zero_value_ == NULL)
{
Location bloc = Linemap::predeclared_location();
// We will change the type later, when we know the size.
Type* byte_type = this->lookup_global("byte")->type_value();
Expression* zero = Expression::make_integer_ul(0, NULL, bloc);
Type* array_type = Type::make_array_type(byte_type, zero);
Variable* var = new Variable(array_type, NULL, true, false, false, bloc);
this->zero_value_ = Named_object::make_variable("go$zerovalue", NULL,
var);
}
// The zero value will be the maximum required size.
int64_t size;
bool ok = type->backend_type_size(this, &size);
if (!ok) {
go_assert(saw_errors());
size = 4;
}
if (size > this->zero_value_size_)
this->zero_value_size_ = size;
int64_t align;
ok = type->backend_type_align(this, &align);
if (!ok) {
go_assert(saw_errors());
align = 4;
}
if (align > this->zero_value_align_)
this->zero_value_align_ = align;
return this->zero_value_;
}
// Return whether V is the zero value variable.
bool
Gogo::is_zero_value(Variable* v) const
{
return this->zero_value_ != NULL && this->zero_value_->var_value() == v;
}
// Return the backend variable for the special zero value, or NULL if
// it is not needed.
Bvariable*
Gogo::backend_zero_value()
{
if (this->zero_value_ == NULL)
return NULL;
Type* byte_type = this->lookup_global("byte")->type_value();
Btype* bbtype_type = byte_type->get_backend(this);
Type* int_type = this->lookup_global("int")->type_value();
Expression* e = Expression::make_integer_int64(this->zero_value_size_,
int_type,
Linemap::unknown_location());
Translate_context context(this, NULL, NULL, NULL);
Bexpression* blength = e->get_backend(&context);
Btype* barray_type = this->backend()->array_type(bbtype_type, blength);
std::string zname = this->zero_value_->name();
Bvariable* zvar =
this->backend()->implicit_variable(zname, barray_type, false,
true, true, this->zero_value_align_);
this->backend()->implicit_variable_set_init(zvar, zname, barray_type,
false, true, true, NULL);
return zvar;
}
// Add statements to INIT_STMTS which run the initialization
// functions for imported packages. This is only used for the "main"
// package.
......@@ -6534,9 +6450,7 @@ Variable::get_backend_variable(Gogo* gogo, Named_object* function,
Btype* btype = type->get_backend(gogo);
Bvariable* bvar;
if (gogo->is_zero_value(this))
bvar = gogo->backend_zero_value();
else if (this->is_global_)
if (this->is_global_)
bvar = backend->global_variable((package == NULL
? gogo->package_name()
: package->package_name()),
......
gcc/go/gofrontend/gogo.h
......@@ -653,20 +653,6 @@ class Gogo
named_types_are_converted() const
{ return this->named_types_are_converted_; }
// Return the variable to use for the zero value of TYPE. All types
// shared the same zero value, and we make sure that it is large
// enough.
Named_object*
zero_value(Type *type);
// Return whether a variable is the zero value variable.
bool
is_zero_value(Variable* v) const;
// Create the zero value variable.
Bvariable*
backend_zero_value();
// Write out the global values.
void
write_globals();
......@@ -821,12 +807,6 @@ class Gogo
std::string pkgpath_symbol_;
// The prefix to use for symbols, from the -fgo-prefix option.
std::string prefix_;
// The special zero value variable.
Named_object* zero_value_;
// The size of the zero value variable.
int64_t zero_value_size_;
// The alignment of the zero value variable, in bytes.
int64_t zero_value_align_;
// Whether pkgpath_ has been set.
bool pkgpath_set_;
// Whether an explicit package path was set by -fgo-pkgpath.
......
gcc/go/gofrontend/types.cc
......@@ -1529,7 +1529,7 @@ Type::make_type_descriptor_type()
// The type descriptor type.
Struct_type* type_descriptor_type =
Type::make_builtin_struct_type(12,
Type::make_builtin_struct_type(11,
"kind", uint8_type,
"align", uint8_type,
"fieldAlign", uint8_type,
......@@ -1541,8 +1541,7 @@ Type::make_type_descriptor_type()
"string", pointer_string_type,
"", pointer_uncommon_type,
"ptrToThis",
pointer_type_descriptor_type,
"zero", unsafe_pointer_type);
pointer_type_descriptor_type);
Named_type* named = Type::make_builtin_named_type("commonType",
type_descriptor_type);
......@@ -2074,15 +2073,6 @@ Type::type_descriptor_constructor(Gogo* gogo, int runtime_type_kind,
}
++p;
go_assert(p->is_field_name("zero"));
Expression* z = Expression::make_var_reference(gogo->zero_value(this), bloc);
z = Expression::make_unary(OPERATOR_AND, z, bloc);
Type* void_type = Type::make_void_type();
Type* unsafe_pointer_type = Type::make_pointer_type(void_type);
z = Expression::make_cast(unsafe_pointer_type, z, bloc);
vals->push_back(z);
++p;
go_assert(p == fields->end());
return Expression::make_struct_composite_literal(td_type, vals, bloc);
......
libgo/go/reflect/type.go
......@@ -262,7 +262,6 @@ type rtype struct {
string *string // string form; unnecessary but undeniably useful
*uncommonType // (relatively) uncommon fields
ptrToThis *rtype // type for pointer to this type, if used in binary or has methods
zero unsafe.Pointer // pointer to zero value
}
// Method on non-interface type
......@@ -1129,7 +1128,6 @@ func (t *rtype) ptrTo() *rtype {
p.uncommonType = nil
p.ptrToThis = nil
p.zero = unsafe.Pointer(&make([]byte, p.size)[0])
p.elem = t
if t.kind&kindNoPointers != 0 {
......@@ -1505,7 +1503,6 @@ func ChanOf(dir ChanDir, t Type) Type {
ch.elem = typ
ch.uncommonType = nil
ch.ptrToThis = nil
ch.zero = unsafe.Pointer(&make([]byte, ch.size)[0])
ch.gc = unsafe.Pointer(&chanGC{
width: ch.size,
......@@ -1561,7 +1558,6 @@ func MapOf(key, elem Type) Type {
mt.elem = etyp
mt.uncommonType = nil
mt.ptrToThis = nil
mt.zero = unsafe.Pointer(&make([]byte, mt.size)[0])
// mt.gc = unsafe.Pointer(&ptrGC{
// width: unsafe.Sizeof(uintptr(0)),
// op: _GC_PTR,
......@@ -1848,7 +1844,6 @@ func SliceOf(t Type) Type {
slice.elem = typ
slice.uncommonType = nil
slice.ptrToThis = nil
slice.zero = unsafe.Pointer(&make([]byte, slice.size)[0])
if typ.size == 0 {
slice.gc = unsafe.Pointer(&sliceEmptyGCProg)
......@@ -1920,7 +1915,6 @@ func arrayOf(count int, elem Type) Type {
// TODO:
array.uncommonType = nil
array.ptrToThis = nil
array.zero = unsafe.Pointer(&make([]byte, array.size)[0])
array.len = uintptr(count)
array.slice = slice.(*rtype)
......
libgo/runtime/go-type.h
......@@ -108,11 +108,6 @@ struct __go_type_descriptor
/* The descriptor for the type which is a pointer to this type.
This may be NULL. */
const struct __go_type_descriptor *__pointer_to_this;
/* A pointer to a zero value for this type. All types will point to
the same zero value, go$zerovalue, which is a common variable so
that it will be large enough. */
void *__zero;
};
/* The information we store for each method of a type. */
......
libgo/runtime/go-unsafe-pointer.c
......@@ -10,9 +10,6 @@
#include "go-type.h"
#include "mgc0.h"
/* A pointer with a zero value. */
static void *zero_pointer;
/* This file provides the type descriptor for the unsafe.Pointer type.
The unsafe package is defined by the compiler itself, which means
that there is no package to compile to define the type
......@@ -64,9 +61,7 @@ const struct __go_type_descriptor unsafe_Pointer =
/* __uncommon */
NULL,
/* __pointer_to_this */
NULL,
/* __zero */
&zero_pointer
NULL
};
/* We also need the type descriptor for the pointer to unsafe.Pointer,
......@@ -109,9 +104,7 @@ const struct __go_ptr_type pointer_unsafe_Pointer =
/* __uncommon */
NULL,
/* __pointer_to_this */
NULL,
/* __zero */
&zero_pointer
NULL
},
/* __element_type */
&unsafe_Pointer
......
libgo/runtime/proc.c
......@@ -538,9 +538,7 @@ static struct __go_channel_type chan_bool_type_descriptor =
/* __uncommon */
NULL,
/* __pointer_to_this */
NULL,
/* __zero */
NULL /* This value doesn't matter */
NULL
},
/* __element_type */
&bool_type_descriptor,
......
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