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| author | Than McIntosh <thanm@google.com> | 2023-08-15 10:24:41 -0400 |
|---|---|---|
| committer | Than McIntosh <thanm@google.com> | 2023-08-15 15:39:57 +0000 |
| commit | 1e245d21b8ec0a4afb459b6f146cbc0c47f5cb24 (patch) | |
| tree | dc7e025ed3626e7f820129deeb64a06db1e55f51 /src | |
| parent | fc212a9307980b8d29fff1736f0ba1ed1e5898a2 (diff) | |
| download | go-1e245d21b8ec0a4afb459b6f146cbc0c47f5cb24.tar.xz | |
cmd/internal/archive: skip sentinel archive entries created by Go cmd
When reading an archive, check for the presence of sentinel entries
created by the Go command. These zero-sized marker entries don't contain
any useful symbols, but rather are there to communicate info to the
linker; ignore them during symbol dumping.
Fixes #62036.
Change-Id: Ied017b0c5b92a3cf6fd13bb9c9f3a9664e4f20f8
Reviewed-on: https://go-review.googlesource.com/c/go/+/519635
Run-TryBot: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Diffstat (limited to 'src')
| -rw-r--r-- | src/cmd/go/testdata/script/cgo_suspect_flag_force_external.txt | 20 | ||||
| -rw-r--r-- | src/cmd/internal/archive/archive.go | 18 | ||||
| -rw-r--r-- | src/cmd/internal/objfile/goobj.go | 2 |
3 files changed, 39 insertions, 1 deletions
diff --git a/src/cmd/go/testdata/script/cgo_suspect_flag_force_external.txt b/src/cmd/go/testdata/script/cgo_suspect_flag_force_external.txt index e5bcdc6cfa..d555278865 100644 --- a/src/cmd/go/testdata/script/cgo_suspect_flag_force_external.txt +++ b/src/cmd/go/testdata/script/cgo_suspect_flag_force_external.txt @@ -95,6 +95,9 @@ go build -ldflags=-tmpdir=tmp4 -o $devnull ./usesExplicitCgo & [cgolinkext] go list ./usesInternalCgo [!cgolinkext] go build '-ldflags=-tmpdir=tmp5 -linkmode=internal' -o $devnull ./usesInternalCgo & +# Sixth build: explicit CGO use in a non-main package. +go build -o p.a ./nonMainPackageUsesExplicitCgo & + wait # Check first build: no external linking expected @@ -113,6 +116,10 @@ exists tmp4/go.o # Fifth build: explicit CGO, -linkmode=internal. ! exists tmp5/go.o +# Sixth build: make sure that "go tool nm" doesn't get confused +# by the presence of the "preferlinkext" sentinel. +go tool nm p.a + -- go.mod -- module cgo.example @@ -153,3 +160,16 @@ import "C" func main() { println(C.meaningOfLife()) } + +-- nonMainPackageUsesExplicitCgo/main.go -- + +package p + +/* +int meaningOfLife() { return 42; } +*/ +import "C" + +func PrintIt() { + println(C.meaningOfLife()) +} diff --git a/src/cmd/internal/archive/archive.go b/src/cmd/internal/archive/archive.go index 8ac50e202f..393034d776 100644 --- a/src/cmd/internal/archive/archive.go +++ b/src/cmd/internal/archive/archive.go @@ -70,6 +70,7 @@ const ( EntryPkgDef EntryType = iota EntryGoObj EntryNativeObj + EntrySentinelNonObj ) func (e *Entry) String() string { @@ -357,6 +358,23 @@ func (r *objReader) parseArchive(verbose bool) error { Data: Data{r.offset, size}, }) r.skip(size) + case "preferlinkext", "dynimportfail": + if size == 0 { + // These are not actual objects, but rather sentinel + // entries put into the archive by the Go command to + // be read by the linker. See #62036. + r.a.Entries = append(r.a.Entries, Entry{ + Name: name, + Type: EntrySentinelNonObj, + Mtime: mtime, + Uid: uid, + Gid: gid, + Mode: mode, + Data: Data{r.offset, size}, + }) + break + } + fallthrough default: var typ EntryType var o *GoObj diff --git a/src/cmd/internal/objfile/goobj.go b/src/cmd/internal/objfile/goobj.go index 24d2d0bb5c..a0a2a1799b 100644 --- a/src/cmd/internal/objfile/goobj.go +++ b/src/cmd/internal/objfile/goobj.go @@ -35,7 +35,7 @@ func openGoFile(f *os.File) (*File, error) { L: for _, e := range a.Entries { switch e.Type { - case archive.EntryPkgDef: + case archive.EntryPkgDef, archive.EntrySentinelNonObj: continue case archive.EntryGoObj: o := e.Obj |