cmd/internal/obj: flag init functions in object file
Introduce a flag in the object file indicating whether a given
function corresponds to a compiler-generated (not user-written) init
function, such as "os.init" or "syscall.init". Add code to the
compiler to fill in the correct value for the flag, and add support to
the loader package in the linker for testing the flag. The new loader
API is currently unused, but will be needed in the next CL in this
stack.
Updates #2559.
Updates #36021.
Updates #14840.
Change-Id: Iea7ad2adda487e4af7a44f062f9817977c53b394
Reviewed-on: https://go-review.googlesource.com/c/go/+/463855
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Than McIntosh <thanm@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
diff --git a/src/cmd/compile/internal/ir/abi.go b/src/cmd/compile/internal/ir/abi.go
index 8cd1606..041448f 100644
--- a/src/cmd/compile/internal/ir/abi.go
+++ b/src/cmd/compile/internal/ir/abi.go
@@ -53,6 +53,9 @@
if f.ReflectMethod() {
flag |= obj.REFLECTMETHOD
}
+ if f.IsPackageInit() {
+ flag |= obj.PKGINIT
+ }
// Clumsy but important.
// For functions that could be on the path of invoking a deferred
diff --git a/src/cmd/compile/internal/ir/func.go b/src/cmd/compile/internal/ir/func.go
index 8f56c6f..fba6228 100644
--- a/src/cmd/compile/internal/ir/func.go
+++ b/src/cmd/compile/internal/ir/func.go
@@ -204,6 +204,7 @@
funcInstrumentBody // add race/msan/asan instrumentation during SSA construction
funcOpenCodedDeferDisallowed // can't do open-coded defers
funcClosureCalled // closure is only immediately called; used by escape analysis
+ funcPackageInit // compiler emitted .init func for package
)
type SymAndPos struct {
@@ -225,6 +226,7 @@
func (f *Func) InstrumentBody() bool { return f.flags&funcInstrumentBody != 0 }
func (f *Func) OpenCodedDeferDisallowed() bool { return f.flags&funcOpenCodedDeferDisallowed != 0 }
func (f *Func) ClosureCalled() bool { return f.flags&funcClosureCalled != 0 }
+func (f *Func) IsPackageInit() bool { return f.flags&funcPackageInit != 0 }
func (f *Func) SetDupok(b bool) { f.flags.set(funcDupok, b) }
func (f *Func) SetWrapper(b bool) { f.flags.set(funcWrapper, b) }
@@ -240,6 +242,7 @@
func (f *Func) SetInstrumentBody(b bool) { f.flags.set(funcInstrumentBody, b) }
func (f *Func) SetOpenCodedDeferDisallowed(b bool) { f.flags.set(funcOpenCodedDeferDisallowed, b) }
func (f *Func) SetClosureCalled(b bool) { f.flags.set(funcClosureCalled, b) }
+func (f *Func) SetIsPackageInit(b bool) { f.flags.set(funcPackageInit, b) }
func (f *Func) SetWBPos(pos src.XPos) {
if base.Debug.WB != 0 {
diff --git a/src/cmd/compile/internal/pkginit/init.go b/src/cmd/compile/internal/pkginit/init.go
index 9d4c435..fac1ad7 100644
--- a/src/cmd/compile/internal/pkginit/init.go
+++ b/src/cmd/compile/internal/pkginit/init.go
@@ -36,6 +36,7 @@
}
fn.Dcl = append(fn.Dcl, typecheck.InitTodoFunc.Dcl...)
typecheck.InitTodoFunc.Dcl = nil
+ fn.SetIsPackageInit(true)
// Suppress useless "can inline" diagnostics.
// Init functions are only called dynamically.
diff --git a/src/cmd/internal/goobj/objfile.go b/src/cmd/internal/goobj/objfile.go
index 7b985fae..547b826 100644
--- a/src/cmd/internal/goobj/objfile.go
+++ b/src/cmd/internal/goobj/objfile.go
@@ -303,6 +303,7 @@
SymFlagUsedInIface = 1 << iota
SymFlagItab
SymFlagDict
+ SymFlagPkgInit
)
// Returns the length of the name of the symbol.
@@ -333,6 +334,7 @@
func (s *Sym) UsedInIface() bool { return s.Flag2()&SymFlagUsedInIface != 0 }
func (s *Sym) IsItab() bool { return s.Flag2()&SymFlagItab != 0 }
func (s *Sym) IsDict() bool { return s.Flag2()&SymFlagDict != 0 }
+func (s *Sym) IsPkgInit() bool { return s.Flag2()&SymFlagPkgInit != 0 }
func (s *Sym) SetName(x string, w *Writer) {
binary.LittleEndian.PutUint32(s[:], uint32(len(x)))
diff --git a/src/cmd/internal/obj/link.go b/src/cmd/internal/obj/link.go
index 6d40b33..d153afb 100644
--- a/src/cmd/internal/obj/link.go
+++ b/src/cmd/internal/obj/link.go
@@ -724,6 +724,9 @@
// IsPcdata indicates this is a pcdata symbol.
AttrPcdata
+ // PkgInit indicates this is a compiler-generated package init func.
+ AttrPkgInit
+
// attrABIBase is the value at which the ABI is encoded in
// Attribute. This must be last; all bits after this are
// assumed to be an ABI value.
@@ -752,6 +755,7 @@
func (a *Attribute) ContentAddressable() bool { return a.load()&AttrContentAddressable != 0 }
func (a *Attribute) ABIWrapper() bool { return a.load()&AttrABIWrapper != 0 }
func (a *Attribute) IsPcdata() bool { return a.load()&AttrPcdata != 0 }
+func (a *Attribute) IsPkgInit() bool { return a.load()&AttrPkgInit != 0 }
func (a *Attribute) Set(flag Attribute, value bool) {
for {
@@ -800,6 +804,7 @@
{bit: AttrIndexed, s: ""},
{bit: AttrContentAddressable, s: ""},
{bit: AttrABIWrapper, s: "ABIWRAPPER"},
+ {bit: AttrPkgInit, s: "PKGINIT"},
}
// String formats a for printing in as part of a TEXT prog.
diff --git a/src/cmd/internal/obj/objfile.go b/src/cmd/internal/obj/objfile.go
index 85e49e2..73c29d9 100644
--- a/src/cmd/internal/obj/objfile.go
+++ b/src/cmd/internal/obj/objfile.go
@@ -344,6 +344,9 @@
if strings.HasPrefix(s.Name, w.ctxt.Pkgpath) && strings.HasPrefix(s.Name[len(w.ctxt.Pkgpath):], ".") && strings.HasPrefix(s.Name[len(w.ctxt.Pkgpath)+1:], objabi.GlobalDictPrefix) {
flag2 |= goobj.SymFlagDict
}
+ if s.IsPkgInit() {
+ flag2 |= goobj.SymFlagPkgInit
+ }
name := s.Name
if strings.HasPrefix(name, "gofile..") {
name = filepath.ToSlash(name)
diff --git a/src/cmd/internal/obj/plist.go b/src/cmd/internal/obj/plist.go
index fe9d2e1..835f37f 100644
--- a/src/cmd/internal/obj/plist.go
+++ b/src/cmd/internal/obj/plist.go
@@ -193,6 +193,7 @@
s.Set(AttrABIWrapper, flag&ABIWRAPPER != 0)
s.Set(AttrNeedCtxt, flag&NEEDCTXT != 0)
s.Set(AttrNoFrame, flag&NOFRAME != 0)
+ s.Set(AttrPkgInit, flag&PKGINIT != 0)
s.Type = objabi.STEXT
ctxt.Text = append(ctxt.Text, s)
diff --git a/src/cmd/internal/obj/textflag.go b/src/cmd/internal/obj/textflag.go
index 5ae7502..bf9c8c9 100644
--- a/src/cmd/internal/obj/textflag.go
+++ b/src/cmd/internal/obj/textflag.go
@@ -55,4 +55,7 @@
// Function is an ABI wrapper.
ABIWRAPPER = 4096
+
+ // Function is a compiler-generated package init function.
+ PKGINIT = 8192
)
diff --git a/src/cmd/link/internal/loader/loader.go b/src/cmd/link/internal/loader/loader.go
index 2ac17f4..e3ee819 100644
--- a/src/cmd/link/internal/loader/loader.go
+++ b/src/cmd/link/internal/loader/loader.go
@@ -1190,6 +1190,15 @@
return r.Sym(li).IsDict()
}
+// Returns whether this symbol is a compiler-generated package init func.
+func (l *Loader) IsPkgInit(i Sym) bool {
+ if l.IsExternal(i) {
+ return false
+ }
+ r, li := l.toLocal(i)
+ return r.Sym(li).IsPkgInit()
+}
+
// Return whether this is a trampoline of a deferreturn call.
func (l *Loader) IsDeferReturnTramp(i Sym) bool {
return l.deferReturnTramp[i]
