[dev.link] cmd/link: delete sym.Attribute
Change-Id: I1a3ad5e02e9586168a0c5cd37bee37ab5b65e501
Reviewed-on: https://go-review.googlesource.com/c/go/+/234039
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>
diff --git a/src/cmd/link/internal/sym/attribute.go b/src/cmd/link/internal/sym/attribute.go
deleted file mode 100644
index eda3fe6..0000000
--- a/src/cmd/link/internal/sym/attribute.go
+++ /dev/null
@@ -1,129 +0,0 @@
-// Copyright 2017 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-package sym
-
-import "sync/atomic"
-
-// Attribute is a set of common symbol attributes.
-type Attribute int32
-
-const (
- // AttrDuplicateOK marks a symbol that can be present in multiple object
- // files.
- AttrDuplicateOK Attribute = 1 << iota
- // AttrExternal marks function symbols loaded from host object files.
- AttrExternal
- // AttrNoSplit marks functions that cannot split the stack; the linker
- // cares because it checks that there are no call chains of nosplit
- // functions that require more than StackLimit bytes (see
- // lib.go:dostkcheck)
- AttrNoSplit
- // AttrReachable marks symbols that are transitively referenced from the
- // entry points. Unreachable symbols are not written to the output.
- AttrReachable
- // AttrCgoExportDynamic and AttrCgoExportStatic mark symbols referenced
- // by directives written by cgo (in response to //export directives in
- // the source).
- AttrCgoExportDynamic
- AttrCgoExportStatic
- // AttrSpecial marks symbols that do not have their address (i.e. Value)
- // computed by the usual mechanism of data.go:dodata() &
- // data.go:address().
- AttrSpecial
- // AttrStackCheck is used by dostkcheck to only check each NoSplit
- // function's stack usage once.
- AttrStackCheck
- // AttrNotInSymbolTable marks symbols that are not written to the symbol table.
- AttrNotInSymbolTable
- // AttrOnList marks symbols that are on some list (such as the list of
- // all text symbols, or one of the lists of data symbols) and is
- // consulted to avoid bugs where a symbol is put on a list twice.
- AttrOnList
- // AttrLocal marks symbols that are only visible within the module
- // (executable or shared library) being linked. Only relevant when
- // dynamically linking Go code.
- AttrLocal
- // AttrReflectMethod marks certain methods from the reflect package that
- // can be used to call arbitrary methods. If no symbol with this bit set
- // is marked as reachable, more dead code elimination can be done.
- AttrReflectMethod
- // AttrMakeTypelink Amarks types that should be added to the typelink
- // table. See typelinks.go:typelinks().
- AttrMakeTypelink
- // AttrShared marks symbols compiled with the -shared option.
- AttrShared
- // AttrVisibilityHidden symbols are ELF symbols with
- // visibility set to STV_HIDDEN. They become local symbols in
- // the final executable. Only relevant when internally linking
- // on an ELF platform.
- AttrVisibilityHidden
- // AttrSubSymbol mostly means that the symbol appears on the Sub list of some
- // other symbol. Unfortunately, it's not 100% reliable; at least, it's not set
- // correctly for the .TOC. symbol in Link.dodata. Usually the Outer field of the
- // symbol points to the symbol whose list it is on, but that it is not set for the
- // symbols added to .windynamic in initdynimport in pe.go.
- //
- // TODO(mwhudson): fix the inconsistencies noticed above.
- //
- // Sub lists are used when loading host objects (sections from the host object
- // become regular linker symbols and symbols go on the Sub list of their section)
- // and for constructing the global offset table when internally linking a dynamic
- // executable.
- //
- // TODO(mwhudson): perhaps a better name for this is AttrNonGoSymbol.
- AttrSubSymbol
- // AttrContainer is set on text symbols that are present as the .Outer for some
- // other symbol.
- AttrContainer
- // AttrTopFrame means that the function is an entry point and unwinders
- // should stop when they hit this function.
- AttrTopFrame
- // AttrReadOnly indicates whether the symbol's content (Symbol.P) is backed by
- // read-only memory.
- AttrReadOnly
- // 19 attributes defined so far.
-)
-
-func (a *Attribute) load() Attribute { return Attribute(atomic.LoadInt32((*int32)(a))) }
-
-func (a *Attribute) DuplicateOK() bool { return a.load()&AttrDuplicateOK != 0 }
-func (a *Attribute) External() bool { return a.load()&AttrExternal != 0 }
-func (a *Attribute) NoSplit() bool { return a.load()&AttrNoSplit != 0 }
-func (a *Attribute) Reachable() bool { return a.load()&AttrReachable != 0 }
-func (a *Attribute) CgoExportDynamic() bool { return a.load()&AttrCgoExportDynamic != 0 }
-func (a *Attribute) CgoExportStatic() bool { return a.load()&AttrCgoExportStatic != 0 }
-func (a *Attribute) Special() bool { return a.load()&AttrSpecial != 0 }
-func (a *Attribute) StackCheck() bool { return a.load()&AttrStackCheck != 0 }
-func (a *Attribute) NotInSymbolTable() bool { return a.load()&AttrNotInSymbolTable != 0 }
-func (a *Attribute) OnList() bool { return a.load()&AttrOnList != 0 }
-func (a *Attribute) Local() bool { return a.load()&AttrLocal != 0 }
-func (a *Attribute) ReflectMethod() bool { return a.load()&AttrReflectMethod != 0 }
-func (a *Attribute) MakeTypelink() bool { return a.load()&AttrMakeTypelink != 0 }
-func (a *Attribute) Shared() bool { return a.load()&AttrShared != 0 }
-func (a *Attribute) VisibilityHidden() bool { return a.load()&AttrVisibilityHidden != 0 }
-func (a *Attribute) SubSymbol() bool { return a.load()&AttrSubSymbol != 0 }
-func (a *Attribute) Container() bool { return a.load()&AttrContainer != 0 }
-func (a *Attribute) TopFrame() bool { return a.load()&AttrTopFrame != 0 }
-func (a *Attribute) ReadOnly() bool { return a.load()&AttrReadOnly != 0 }
-
-func (a *Attribute) CgoExport() bool {
- return a.CgoExportDynamic() || a.CgoExportStatic()
-}
-
-func (a *Attribute) Set(flag Attribute, value bool) {
- // XXX it would be nice if we have atomic And, Or.
- for {
- a0 := a.load()
- var anew Attribute
- if value {
- anew = a0 | flag
- } else {
- anew = a0 &^ flag
- }
- if atomic.CompareAndSwapInt32((*int32)(a), int32(a0), int32(anew)) {
- return
- }
- }
-}
