Commit b531eb30 authored by David Crawshaw's avatar David Crawshaw

runtime: reorder modules so main.main comes first

Modules appear in the moduledata linked list in the order they are
loaded by the dynamic loader, with one exception: the
firstmoduledata itself the module that contains the runtime.
This is not always the first module (when using -buildmode=shared,
it is typically libstd.so, the second module).

The order matters for typelinksinit, so we swap the first module
with whatever module contains the main function.

Updates #18729

This fixes the test case extracted with -linkshared, and now

	go test -linkshared encoding/...

passes. However the original issue about a plugin failure is not
yet fixed.

Change-Id: I9f399ecc3518e22e6b0a350358e90b0baa44ac96
Reviewed-on: https://go-review.googlesource.com/35644
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: default avatarBrad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: default avatarMichael Hudson-Doyle <michael.hudson@canonical.com>
Reviewed-by: default avatarIan Lance Taylor <iant@golang.org>
parent 165cfbc4
......@@ -5,6 +5,8 @@ import (
"reflect"
)
var SlicePtr interface{} = &[]int{}
var V int = 1
var HasMask []string = []string{"hi"}
......
......@@ -19,6 +19,8 @@ func F() *C {
return nil
}
var slicePtr interface{} = &[]int{}
func main() {
defer depBase.ImplementedInAsm()
// This code below causes various go.itab.* symbols to be generated in
......@@ -32,4 +34,11 @@ func main() {
if reflect.TypeOf(F).Out(0) != reflect.TypeOf(c) {
panic("bad reflection results, see golang.org/issue/18252")
}
sp := reflect.New(reflect.TypeOf(slicePtr).Elem())
s := sp.Interface()
if reflect.TypeOf(s) != reflect.TypeOf(slicePtr) {
panic("bad reflection results, see golang.org/issue/18729")
}
}
......@@ -285,6 +285,25 @@ func modulesinit() {
md.gcbssmask = progToPointerMask((*byte)(unsafe.Pointer(md.gcbss)), md.ebss-md.bss)
}
}
// Modules appear in the moduledata linked list in the order they are
// loaded by the dynamic loader, with one exception: the
// firstmoduledata itself the module that contains the runtime. This
// is not always the first module (when using -buildmode=shared, it
// is typically libstd.so, the second module). The order matters for
// typelinksinit, so we swap the first module with whatever module
// contains the main function.
//
// See Issue #18729.
mainText := funcPC(main_main)
for i, md := range *modules {
if md.text <= mainText && mainText <= md.etext {
(*modules)[0] = md
(*modules)[i] = &firstmoduledata
break
}
}
atomicstorep(unsafe.Pointer(&modulesSlice), unsafe.Pointer(modules))
}
......
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