cmd/compile: method is inlined instead of loaded from shared library

[davidlazar]

$ go version
go version devel +4a7cf960c3 Sat Mar 4 02:56:37 2017 +0000 linux/amd64

TestTwoGopathShlibs from misc/cgo/testshared fails when mid-stack inlining is enabled. To test with mid-stack inlining, we need to run the test by hand:

$ cd misc/cgo/testshared
$ export GOPATH=$PWD
$ go install -gcflags '-l=4' -installsuffix=6129484611666145821 -v -buildmode=shared runtime sync/atomic
$ go install -gcflags '-l=4' -installsuffix=6129484611666145821 -v -buildmode=shared -linkshared depBase
$ go install -gcflags '-l=4' -installsuffix=6129484611666145821 -v -buildmode=shared -linkshared dep2
$ go install -gcflags '-l=4' -installsuffix=6129484611666145821 -v -linkshared exe2

The last command fails with the output:

# exe2
main.main: relocation target os.Stdout not defined
main.main: relocation target type.*os.File not defined
go.itab.*reflect.rtype,reflect.Type: relocation target type.8b7X1see not defined
go.itab.*reflect.rtype,reflect.Type: relocation target type.H0+h5nWH not defined
main.main: undefined: "os.Stdout"
main.main: undefined: "type.*os.File"
go.itab.*reflect.rtype,reflect.Type: undefined: "type.8b7X1see"
go.itab.*reflect.rtype,reflect.Type: undefined: "type.H0+h5nWH"

The call to (*depBase.Dep).Method in exe2.go is inlined but this method should be dynamically loaded.

[davidlazar]

cc @mwhudson @ianlancetaylor

[mwhudson]

Well it was a conscious decision at the time to allow inlining across module boundaries (partly because it was the easiest thing to do, perhaps). And those linker errors look like the compiler is violating some invariants that shouldn't really have anything to do with inlining. But I haven't looked at the details yet...

[aclements]

@mwhudson, isn't one of the main points of shared objects to allow a shared object to be upgraded in an ABI-compatible way (security fixes, etc) without updating everything that depends on it?

[seankhliao]

Obsoleted by #47788