gollvm: error: undefined reference to 'runtime.strhash..f.1' #52899
Description
# command-line-arguments
/tmp/go-build3560960528/b001/_pkg_.a(_go_.o):gomodule:type..map_6string_7int: error: undefined reference to 'runtime.strhash..f.1'
The error can be reproduced with the test case and the trunk.
package main
import "unsafe"
var E_hash func(unsafe.Pointer, uintptr) uintptr = strhash
//go:noescape
//go:linkname strhash runtime.strhash
func strhash(unsafe.Pointer, uintptr) uintptr
func pointer(s string) unsafe.Pointer {
return unsafe.Pointer(&s)
}
func main() {
var m map[string]int
m = make(map[string]int)
m["123"] = 1
if E_hash == nil {
panic("Oops")
}
if E_hash(pointer("123"), 0) != E_hash(pointer("123"), 0) {
panic("Oops")
}
}Func_descriptor_expression::do_get_backend deals with function declaration and definition differently, which can request the backend twice to create global variables representing the function pointer. Unfortunately, the GOLLVM bridge uses module_->getGlobalVariable(gname) (without parameter AllowLocal) to check existing globals, which cannot find GlobalVariable with local linkage. To fix this issue, we should set is_hidden = false in Func_descriptor_expression::do_get_backend if the Function or Function_declaration has a non-empty asm_name.
Moreover, we need to set AllowLocal = true when trying to find globals via module_->getGlobalVariable and resolve linkage/type conflicts if necessary in GOLLVM bridge. Otherwise, the LLVM backend will rename the global by itself, which will lead to undefined reference errors.