Revert "cmd/link: fix GC data reading from shared library"
This reverts CL 240462.
Reason for revert: test fails on PPC64LE.
Updates #39927.
Change-Id: I4f14fd0c36e604a80ae9f2f86d1e643e28945e93
Reviewed-on: https://go-review.googlesource.com/c/go/+/240616
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
diff --git a/misc/cgo/testshared/shared_test.go b/misc/cgo/testshared/shared_test.go
index f8dabbe..fda3d2c 100644
--- a/misc/cgo/testshared/shared_test.go
+++ b/misc/cgo/testshared/shared_test.go
@@ -38,15 +38,7 @@
// run runs a command and calls t.Errorf if it fails.
func run(t *testing.T, msg string, args ...string) {
- runWithEnv(t, msg, nil, args...)
-}
-
-// runWithEnv runs a command under the given environment and calls t.Errorf if it fails.
-func runWithEnv(t *testing.T, msg string, env []string, args ...string) {
c := exec.Command(args[0], args[1:]...)
- if len(env) != 0 {
- c.Env = append(os.Environ(), env...)
- }
if output, err := c.CombinedOutput(); err != nil {
t.Errorf("executing %s (%s) failed %s:\n%s", strings.Join(args, " "), msg, err, output)
}
@@ -1042,11 +1034,3 @@
func TestPackageOrder(t *testing.T) {
goCmd(t, "install", "-buildmode=shared", "-linkshared", "./issue39777/a", "./issue39777/b")
}
-
-// Test that GC data are generated correctly by the linker when it needs a type defined in
-// a shared library. See issue 39927.
-func TestGCData(t *testing.T) {
- goCmd(t, "install", "-buildmode=shared", "-linkshared", "./gcdata/p")
- goCmd(t, "build", "-linkshared", "./gcdata/main")
- runWithEnv(t, "running gcdata/main", []string{"GODEBUG=clobberfree=1"}, "./main")
-}
diff --git a/misc/cgo/testshared/testdata/gcdata/main/main.go b/misc/cgo/testshared/testdata/gcdata/main/main.go
deleted file mode 100644
index 394862f..0000000
--- a/misc/cgo/testshared/testdata/gcdata/main/main.go
+++ /dev/null
@@ -1,37 +0,0 @@
-// Copyright 2020 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.
-
-// Test that GC data is generated correctly for global
-// variables with types defined in a shared library.
-// See issue 39927.
-
-// This test run under GODEBUG=clobberfree=1. The check
-// *x[i] == 12345 depends on this debug mode to clobber
-// the value if the object is freed prematurely.
-
-package main
-
-import (
- "fmt"
- "runtime"
- "testshared/gcdata/p"
-)
-
-var x p.T
-
-func main() {
- for i := range x {
- x[i] = new(int)
- *x[i] = 12345
- }
- runtime.GC()
- runtime.GC()
- runtime.GC()
- for i := range x {
- if *x[i] != 12345 {
- fmt.Printf("x[%d] == %d, want 12345\n", i, *x[i])
- panic("FAIL")
- }
- }
-}
diff --git a/misc/cgo/testshared/testdata/gcdata/p/p.go b/misc/cgo/testshared/testdata/gcdata/p/p.go
deleted file mode 100644
index 1fee754..0000000
--- a/misc/cgo/testshared/testdata/gcdata/p/p.go
+++ /dev/null
@@ -1,7 +0,0 @@
-// Copyright 2020 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 p
-
-type T [10]*int
diff --git a/src/cmd/link/internal/ld/decodesym.go b/src/cmd/link/internal/ld/decodesym.go
index 21bcc3a..e9c87ef 100644
--- a/src/cmd/link/internal/ld/decodesym.go
+++ b/src/cmd/link/internal/ld/decodesym.go
@@ -10,7 +10,6 @@
"cmd/link/internal/loader"
"cmd/link/internal/sym"
"debug/elf"
- "log"
)
// Decoding the type.* symbols. This has to be in sync with
@@ -230,15 +229,8 @@
ptrdata := decodetypePtrdata(ctxt.Arch, symData)
sect := findShlibSection(ctxt, ctxt.loader.SymPkg(s), addr)
if sect != nil {
- bits := ptrdata / int64(ctxt.Arch.PtrSize)
- r := make([]byte, (bits+7)/8)
- // ldshlibsyms avoids closing the ELF file so sect.ReadAt works.
- // If we remove this read (and the ones in decodetypeGcprog), we
- // can close the file.
- _, err := sect.ReadAt(r, int64(addr-sect.Addr))
- if err != nil {
- log.Fatal(err)
- }
+ r := make([]byte, ptrdata/int64(ctxt.Arch.PtrSize))
+ sect.ReadAt(r, int64(addr-sect.Addr))
return r
}
Exitf("cannot find gcmask for %s", ctxt.loader.SymName(s))
@@ -259,15 +251,9 @@
// A gcprog is a 4-byte uint32 indicating length, followed by
// the actual program.
progsize := make([]byte, 4)
- _, err := sect.ReadAt(progsize, int64(addr-sect.Addr))
- if err != nil {
- log.Fatal(err)
- }
+ sect.ReadAt(progsize, int64(addr-sect.Addr))
progbytes := make([]byte, ctxt.Arch.ByteOrder.Uint32(progsize))
- _, err = sect.ReadAt(progbytes, int64(addr-sect.Addr+4))
- if err != nil {
- log.Fatal(err)
- }
+ sect.ReadAt(progbytes, int64(addr-sect.Addr+4))
return append(progsize, progbytes...)
}
Exitf("cannot find gcmask for %s", ctxt.loader.SymName(s))
@@ -282,7 +268,7 @@
func findShlibSection(ctxt *Link, path string, addr uint64) *elf.Section {
for _, shlib := range ctxt.Shlibs {
if shlib.Path == path {
- for _, sect := range shlib.File.Sections[1:] { // skip the NULL section
+ for _, sect := range shlib.File.Sections {
if sect.Addr <= addr && addr <= sect.Addr+sect.Size {
return sect
}
@@ -293,5 +279,8 @@
}
func decodetypeGcprogShlib(ctxt *Link, data []byte) uint64 {
+ if ctxt.Arch.Family == sys.ARM64 {
+ return 0
+ }
return decodeInuxi(ctxt.Arch, data[2*int32(ctxt.Arch.PtrSize)+8+1*int32(ctxt.Arch.PtrSize):], ctxt.Arch.PtrSize)
}
diff --git a/src/cmd/link/internal/ld/lib.go b/src/cmd/link/internal/ld/lib.go
index 802bfb2..61ccc28 100644
--- a/src/cmd/link/internal/ld/lib.go
+++ b/src/cmd/link/internal/ld/lib.go
@@ -2124,9 +2124,7 @@
Errorf(nil, "cannot open shared library: %s", libpath)
return
}
- // Keep the file open as decodetypeGcprog needs to read from it.
- // TODO: fix. Maybe mmap the file.
- //defer f.Close()
+ defer f.Close()
hash, err := readnote(f, ELF_NOTE_GO_NAME, ELF_NOTE_GOABIHASH_TAG)
if err != nil {
