iASL: keep externals for methods that are referenced

At the moment, the external analysis walk attempts to optimize the size
of AML by removing external method declarations that are not called.
This results in the external declaration in the following code being
removed during compilation:

External (EXT0, MethodObj) // EXT0 removed during compilation
if (!CondRefOf (EXT0))
{
    Method (EXT0)
    {
        ...
    }
}

This happens because referencing externals inside of CondRefOf is not a
method call. This results in the first line being removed during
compilation and breaks the re-compilation of the above code after
disassembly. In order to retain the external declaration, change the
external method analysis to look for any named referenced in addition to
method calls.

Signed-off-by: Erik Kaneda <erik.kaneda@intel.com>

source/compiler/aslexternal.c

@@ -280,6 +280,57 @@ ExDoExternal (
 }
 
 
+/*******************************************************************************
+ *
+ * FUNCTION:    ExFindUnvisitedExternal
+ *
+ * PARAMETERS:  Name             - Name to find in the external list
+ *
+ * RETURN:      ACPI_PARSE_OBJECT
+ *
+ * DESCRIPTION: Find an entry in the external list that matches the Name
+ *              argument
+ *
+ ******************************************************************************/
+
+static ACPI_PARSE_OBJECT *
+ExFindUnvisitedExternal (
+    char                    *Name)
+{
+    ACPI_PARSE_OBJECT       *Current;
+    ACPI_PARSE_OBJECT       *NameOp;
+    char                    *ExternalName;
+
+
+    Current = AslGbl_ExternalsListHead;
+    while (Current)
+    {
+        /* Skip if External node already handled */
+
+        if (Current->Asl.Child->Asl.CompileFlags & OP_VISITED)
+        {
+            Current = Current->Asl.Next;
+            continue;
+        }
+
+        NameOp = Current->Asl.Child->Asl.Child;
+        ExternalName = AcpiNsGetNormalizedPathname (NameOp->Asl.Node, TRUE);
+        if (strcmp (Name, ExternalName))
+        {
+            ACPI_FREE (ExternalName);
+            Current = Current->Asl.Next;
+            continue;
+        }
+        else
+        {
+            ACPI_FREE (ExternalName);
+            return Current;
+        }
+    }
+    return NULL;
+}
+
+
 /*******************************************************************************
  *
  * FUNCTION:    ExInsertArgCount
@@ -301,44 +352,21 @@ ExInsertArgCount (
     ACPI_PARSE_OBJECT       *NameOp;
     ACPI_PARSE_OBJECT       *Child;
     ACPI_PARSE_OBJECT       *ArgCountOp;
-    char *                  ExternalName;
     char *                  CallName;
     UINT16                  ArgCount = 0;
     ACPI_STATUS             Status;
 
 
     CallName = AcpiNsGetNormalizedPathname (Op->Asl.Node, TRUE);
 
-    Next = AslGbl_ExternalsListHead;
-    while (Next)
-    {
-        ArgCount = 0;
-
-        /* Skip if External node already handled */
-
-        if (Next->Asl.Child->Asl.CompileFlags & OP_VISITED)
-        {
-            Next = Next->Asl.Next;
-            continue;
-        }
-
-        NameOp = Next->Asl.Child->Asl.Child;
-        ExternalName = AcpiNsGetNormalizedPathname (NameOp->Asl.Node, TRUE);
-        if (strcmp (CallName, ExternalName))
-        {
-            ACPI_FREE (ExternalName);
-            Next = Next->Asl.Next;
-            continue;
-        }
-        ACPI_FREE (ExternalName);
-    }
-
+    Next = ExFindUnvisitedExternal (CallName);
     if (!Next)
     {
        goto Cleanup;
     }
 
     Next->Asl.Child->Asl.CompileFlags |= OP_VISITED;
+    NameOp = Next->Asl.Child->Asl.Child;
 
     /*
      * Since we will reposition Externals to the Root, set Namepath
@@ -392,6 +420,9 @@ ExAmlExternalWalkBegin (
     UINT32                  Level,
     void                    *Context)
 {
+    ACPI_PARSE_OBJECT       *ExternalListOp;
+    char                    *Name;
+
 
     /* External list head saved in the definition block op */
 
@@ -405,6 +436,19 @@ ExAmlExternalWalkBegin (
         return (AE_OK);
     }
 
+    if (Op->Asl.ParseOpcode == PARSEOP_NAMESEG)
+    {
+        Name = AcpiNsGetNormalizedPathname (Op->Asl.Node, TRUE);
+        ExternalListOp = ExFindUnvisitedExternal (Name);
+        if (ExternalListOp)
+        {
+            ExternalListOp->Asl.Child->Asl.CompileFlags |= OP_VISITED;
+        }
+
+        ACPI_FREE (Name);
+        return (AE_OK);
+    }
+
     if (Op->Asl.ParseOpcode != PARSEOP_METHODCALL)
     {
         return (AE_OK);