inline bool hasInitializer() const { return !isDeclaration(); }
/// hasDefinitiveInitializer - Whether the global variable has an initializer,
- /// and this is the initializer that will be used in the final executable.
+ /// and any other instances of the global (this can happen due to weak
+ /// linkage) are guaranteed to have the same initializer.
+ ///
+ /// Note that if you want to transform a global, you must use
+ /// hasUniqueInitializer() instead, because of the *_odr linkage type.
+ ///
+ /// Example:
+ ///
+ /// @a = global SomeType* null - Initializer is both definitive and unique.
+ ///
+ /// @b = global weak SomeType* null - Initializer is neither definitive nor
+ /// unique.
+ ///
+ /// @c = global weak_odr SomeType* null - Initializer is definitive, but not
+ /// unique.
inline bool hasDefinitiveInitializer() const {
return hasInitializer() &&
// The initializer of a global variable with weak linkage may change at
!mayBeOverridden();
}
+ /// hasUniqueInitializer - Whether the global variable has an initializer, and
+ /// any changes made to the initializer will turn up in the final executable.
+ inline bool hasUniqueInitializer() const {
+ return hasInitializer() &&
+ // It's not safe to modify initializers of global variables with weak
+ // linkage, because the linker might choose to discard the initializer and
+ // use the initializer from another instance of the global variable
+ // instead. It is wrong to modify the initializer of a global variable
+ // with *_odr linkage because then different instances of the global may
+ // have different initializers, breaking the One Definition Rule.
+ !isWeakForLinker();
+ }
+
/// getInitializer - Return the initializer for this global variable. It is
/// illegal to call this method if the global is external, because we cannot
/// tell what the value is initialized to!