Changeset ff7ff14a for src

Timestamp:

Jul 31, 2017, 1:58:26 PM (7 years ago)

Author:

Andrew Beach <ajbeach@…>

Branches:

ADT, aaron-thesis, arm-eh, ast-experimental, cleanup-dtors, deferred_resn, demangler, enum, forall-pointer-decay, jacob/cs343-translation, jenkins-sandbox, master, new-ast, new-ast-unique-expr, new-env, no_list, persistent-indexer, pthread-emulation, qualifiedEnum, resolv-new, with_gc

Children:

5c80197

Parents:

61e2761

Message:

Discovered a case where the memory management didn't work, stricter tracking of the current exception fixes the issue.

Location:

src

Files:

• libcfa/exception.c (modified) (4 diffs)
• tests/except-1.c (modified) (1 diff)

src/libcfa/exception.c

@@ -10 +10 @@
 // Created On       : Mon Jun 26 15:13:00 2017
 // Last Modified By : Andrew Beach
-// Last Modified On : Fri Jul 28 12:41:00 2017
-// Update Count     : 3
+// Last Modified On : Mon Jul 31 13:51:00 2017
+// Update Count     : 4
 //
 
@@ -109 +109 @@
 
 // MEMORY MANAGEMENT (still for integers)
-// May have to move to cfa for constructors and destructors.
+// May have to move to cfa for constructors and destructors (references).
+
+struct __cfaehm__node {
+        struct __cfaehm__node * next;
+};
+
+#define NODE_TO_EXCEPT(node) ((exception *)(1 + (node)))
+#define EXCEPT_TO_NODE(except) ((struct __cfaehm__node *)(except) - 1)
 
 // Creates a copy of the indicated exception and sets current_exception to it.
@@ -115 +122 @@
         struct exception_context_t * context = this_exception_context();
 
-        // Try to use the context's store, otherwise use the heap.
-        if ( 0 == context->built_in_storage ) {
-                context->current_exception = &context->built_in_storage;
-        } else {
-                exception * new_copy = malloc( sizeof( exception/*int*/ ) );
-                if ( ! new_copy ) {
-                        // Failure: cannot allocate exception. Terminate thread.
-                        exit(1); // <- thread or program?
-                }
-                context->current_exception = new_copy;
-        }
+        // Allocate memory for the exception.
+        struct __cfaehm__node * store = malloc(
+                sizeof( except ) + sizeof( struct __cfaehm__node ) );
+
+        if ( ! store ) {
+                // Failure: cannot allocate exception. Terminate thread.
+                abort(); // <- Although I think it might be the process.
+        }
+
+        // Add the node to the list:
+        store->next = EXCEPT_TO_NODE(context->current_exception);
+        context->current_exception = NODE_TO_EXCEPT(store);
 
         // Copy the exception to storage.
@@ -136 +144 @@
 
         // DEBUG
-        printf( "Deleting Exception %d (%s)\n", *except,
-                (&context->built_in_storage == except) ? "builtin" : "dynamic" );
+        printf( "Deleting Exception %d\n", *except);
+
+        // Remove the exception from the list.
+        struct __cfaehm__node * to_free = EXCEPT_TO_NODE(except);
+        struct __cfaehm__node * node;
 
         if ( context->current_exception == except ) {
-                // TODO: This should restore it to the last exception.
-                context->current_exception = NULL;
-        }
-        if ( &context->built_in_storage == except ) {
-                // You can't throw the exception '0'.
-                context->built_in_storage = 0;
+                node = to_free->next;
+                context->current_exception = (node) ? NODE_TO_EXCEPT(node) : 0;
         } else {
-                // Only secondary or too large exceptions are thrown.
-                free( except );
-        }
+                node = EXCEPT_TO_NODE(context->current_exception);
+                // It may always be in the first or second position.
+                while( to_free != node->next ) {
+                        node = node->next;
+                }
+                node->next = to_free->next;
+        }
+
+        // Free the old exception node.
+        free( to_free );
 }
 

src/tests/except-1.c

@@ -46 +46 @@
         }
         printf("Part C Complete\n");
+
+        try {
+                try {
+                        throw 7;
+                }
+                catch( 7 ) {
+                        printf("Caught initial throw.\n");
+                        try {
+                                throw 8;
+                        }
+                        catch( 8 ) {
+                                printf("Caught intermediate throw.\n");
+                        }
+                        throw;
+                }
+        }
+        catch( 7 ) {
+                printf("Caught final throw.\n");
+        }
+        printf("Part D Complete\n");
 }