// If val is a constant and addr refers to a global variable which is defined in
// this module or an element thereof, simulate the effect of storing val at addr
// in the global variable's initializer and return true, otherwise return false.
// Precondition: we are compiling the init function.
func (fr *frame) maybeStoreInInitializer(val, addr llvm.Value) bool {
if val.IsAConstant().IsNil() {
return false
}
if !addr.IsAConstantExpr().IsNil() && addr.OperandsCount() >= 2 &&
// TODO(pcc): Explicitly check that this is a constant GEP.
// I don't think there are any other kinds of constantexpr which
// satisfy the conditions we test for here, so this is probably safe.
!addr.Operand(0).IsAGlobalVariable().IsNil() &&
addr.Operand(1).IsNull() {
gv := addr.Operand(0)
globalInit, ok := fr.globalInits[gv]
if !ok {
return false
}
indices := make([]uint32, addr.OperandsCount()-2)
for i := range indices {
op := addr.Operand(i + 2)
if op.IsAConstantInt().IsNil() {
return false
}
indices[i] = uint32(op.ZExtValue())
}
globalInit.update(gv.Type().ElementType(), indices, val)
return true
} else if !addr.IsAGlobalVariable().IsNil() {
if globalInit, ok := fr.globalInits[addr]; ok {
globalInit.update(addr.Type().ElementType(), nil, val)
return true
}
return false
} else {
return false
}
}