Document Global

Author: CodaFi

Sources/LLVMSwift/Global.swift

@@ -1,29 +1,40 @@
 import cllvm
 
+/// A `Global` represents a region of memory allocated at compile time instead
+/// of at runtime.  A global variable must either have an initializer, or make
+/// reference to an external definition that has an initializer.
 public struct Global: IRValue {
-    internal let llvm: LLVMValueRef
-    
-    public var isExternallyInitialized: Bool {
-        get { return LLVMIsExternallyInitialized(llvm) != 0 }
-        set { LLVMSetExternallyInitialized(llvm, newValue.llvm) }
-    }
-    
-    public var initializer: IRValue {
-        get { return LLVMGetInitializer(asLLVM()) }
-        set { LLVMSetInitializer(asLLVM(), newValue.asLLVM()) }
-    }
-    
-    public var isGlobalConstant: Bool {
-        get { return LLVMIsGlobalConstant(asLLVM()) != 0 }
-        set { LLVMSetGlobalConstant(asLLVM(), newValue.llvm) }
-    }
-    
-    public var isThreadLocal: Bool {
-        get { return LLVMIsThreadLocal(asLLVM()) != 0 }
-        set { LLVMSetThreadLocal(asLLVM(), newValue.llvm) }
-    }
-    
-    public func asLLVM() -> LLVMValueRef {
-        return llvm
-    }
+  internal let llvm: LLVMValueRef
+
+  /// Returns whether this global variable has no initializer because it makes
+  /// reference to an initialized value in another translation unit.
+  public var isExternallyInitialized: Bool {
+    get { return LLVMIsExternallyInitialized(llvm) != 0 }
+    set { LLVMSetExternallyInitialized(llvm, newValue.llvm) }
+  }
+
+  /// Retrieves the initializer for this global variable, if it exists.
+  public var initializer: IRValue? {
+    get { return LLVMGetInitializer(asLLVM()) }
+    set { LLVMSetInitializer(asLLVM(), newValue!.asLLVM()) }
+  }
+
+  /// Returns whether this global variable is a constant, whether or not the
+  /// final definition of the global is not.
+  public var isGlobalConstant: Bool {
+    get { return LLVMIsGlobalConstant(asLLVM()) != 0 }
+    set { LLVMSetGlobalConstant(asLLVM(), newValue.llvm) }
+  }
+
+  /// Returns whether this global variable is thread-local.  That is, returns
+  /// if this variable is not shared by multiple threads.
+  public var isThreadLocal: Bool {
+    get { return LLVMIsThreadLocal(asLLVM()) != 0 }
+    set { LLVMSetThreadLocal(asLLVM(), newValue.llvm) }
+  }
+
+  /// Retrieves the underlying LLVM value object.
+  public func asLLVM() -> LLVMValueRef {
+    return llvm
+  }
 }