by Bailey.D.R:

This bug involves a fairly simple usage. There are three parts to this program:

1) A static library (named libhello.a) written in C, exposing function
"say_hello".

2) A package in Go (named hello), exposing func "SayHello", which calls into
the C library.

3) A tool using the hello package (named hello_main) that calls SayHello.


The strange part is that when I compile the static library with -g -O2 -fPIC -m64
-pthread -fno-common, the build succeeds.... but fails with a runtime error:

panic: runtime error: call of nil func value
[signal 0xb code=0x1 addr=0x0 pc=0x0]

goroutine 1 [syscall]:
hello._Cfunc_say_hello(0x2018, 0xb1a2)
    /var/folders/p_/mhydwmzj78n6s6xvf9zly6bm0000gn/T/go-build218171681/hello/_obj/_cgo_defun.c:42 +0x2f
hello.SayHello()
    /var/folders/p_/mhydwmzj78n6s6xvf9zly6bm0000gn/T/go-build218171681/hello/_obj/hello.cgo1.go:10 +0x18
main.main()
    /Users/duane/Projects/go-bug/src/hello_main/hello_main.go:6 +0x18

goroutine 2 [syscall]:
created by runtime.main
    /Users/duane/repo/go/src/pkg/runtime/proc.c:221


However, if I move the c file in with the go package "hello" directory, and
allow it to be compiled in without going through the static library intermediary, it
runs fine.

The two build trees are attached for reference. Simple cd into the directory and
"bash ./build.sh" to compile and run it.

As for my system: I'm running at tip ("go version weekly.2012-03-27
+95dddad64860") on OSX Lion 10.7.3. GCC is version
"i686-apple-darwin11-llvm-gcc-4.2"; however, switching to "vanilla"
gcc or to clang makes no effect.

Attachments:

1. go-bug.tar (8704 bytes)
2. go-working.tar (8192 bytes)