Changes in src/libcfa/exception.c [cbce272:b947fb2]

File:

• src/libcfa/exception.c (modified) (9 diffs)

src/libcfa/exception.c

@@ -9 +9 @@
 // Author           : Andrew Beach
 // Created On       : Mon Jun 26 15:13:00 2017
-// Last Modified By : Andrew Beach
-// Last Modified On : Fri Aug  4 15:20:00 2017
-// Update Count     : 6
-//
-
-#include <stddef.h> // for size_t
+// Last Modified By : Peter A. Buhr
+// Last Modified On : Wed Jul 26 10:37:51 2017
+// Update Count     : 2
+//
 
 #include "exception.h"
@@ -34 +32 @@
 #include "lsda.h"
 
-
-// Base exception vtable is abstract, you should not have base exceptions.
-struct __cfaehm__base_exception_t_vtable
-                ___cfaehm__base_exception_t_vtable_instance = {
-        .parent = NULL,
-        .size = 0,
-        .copy = NULL,
-        .free = NULL,
-        .msg = NULL
-};
-
-
 // Temperary global exception context. Does not work with concurency.
-struct exception_context_t {
+struct shared_stack_t {
     struct __cfaehm__try_resume_node * top_resume;
     struct __cfaehm__try_resume_node * current_resume;
 
-    exception * current_exception;
+    exception current_exception;
     int current_handler_index;
 } shared_stack = {NULL, NULL, 0, 0};
 
-// Get the current exception context.
-// There can be a single global until multithreading occurs, then each stack
-// needs its own. It will have to be updated to handle that.
-struct exception_context_t * this_exception_context() {
-        return &shared_stack;
-}
-//#define SAVE_EXCEPTION_CONTEXT(to_name)
-//struct exception_context_t * to_name = this_exception_context();
-//exception * this_exception() {
-//    return this_exception_context()->current_exception;
-//}
 
 
@@ -80 +55 @@
 
         // DEBUG
-        printf("Throwing resumption exception\n");
+        printf("Throwing resumption exception %d\n", *except);
 
         struct __cfaehm__try_resume_node * original_head = shared_stack.current_resume;
@@ -94 +69 @@
         }
 
-        printf("Unhandled exception\n");
+        printf("Unhandled exception %d\n", *except);
         shared_stack.current_resume = original_head;
 
@@ -119 +94 @@
 // TERMINATION ===============================================================
 
-// MEMORY MANAGEMENT (still for integers)
-// 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.
-static void __cfaehm__allocate_exception( exception * except ) {
-        struct exception_context_t * context = this_exception_context();
-
-        // Allocate memory for the exception.
-        struct __cfaehm__node * store = malloc(
-                sizeof( struct __cfaehm__node ) + except->virtual_table->size );
-
-        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.
-        except->virtual_table->copy( context->current_exception, except );
-}
-
-// Delete the provided exception, unsetting current_exception if relivant.
-static void __cfaehm__delete_exception( exception * except ) {
-        struct exception_context_t * context = this_exception_context();
-
-        // DEBUG
-        printf( "Deleting Exception\n");
-
-        // Remove the exception from the list.
-        struct __cfaehm__node * to_free = EXCEPT_TO_NODE(except);
-        struct __cfaehm__node * node;
-
-        if ( context->current_exception == except ) {
-                node = to_free->next;
-                context->current_exception = (node) ? NODE_TO_EXCEPT(node) : 0;
-        } else {
-                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.
-        except->virtual_table->free( except );
-        free( to_free );
-}
-
-// If this isn't a rethrow (*except==0), delete the provided exception.
-void __cfaehm__cleanup_terminate( void * except ) {
-        if ( *(void**)except ) __cfaehm__delete_exception( *(exception**)except );
-}
-
+// Requires -fexceptions to work.
+
+// Global which defines the current exception.  Currently an int just to make matching easier.
+//int this_exception; (became shared_stack.current_exception)
 
 // We need a piece of storage to raise the exception
@@ -202 +117 @@
 }
 
-// The exception that is being thrown must already be stored.
-__attribute__((noreturn)) void __cfaehm__begin_unwind(void) {
-        if ( ! this_exception_context()->current_exception ) {
-                printf("UNWIND ERROR missing exception in begin unwind\n");
-                abort();
-        }
-
+void __cfaehm__throw_terminate( exception * val ) {
+        // Store the current exception
+        shared_stack.current_exception = *val;
+
+        // DEBUG
+        printf("Throwing termination exception %d\n", *val);
 
         // Call stdlibc to raise the exception
@@ -234 +148 @@
 }
 
-void __cfaehm__throw_terminate( exception * val ) {
-        // DEBUG
-        printf("Throwing termination exception\n");
-
-        __cfaehm__allocate_exception( val );
-        __cfaehm__begin_unwind();
-}
-
+// Nesting this the other way would probably be faster.
 void __cfaehm__rethrow_terminate(void) {
         // DEBUG
         printf("Rethrowing termination exception\n");
 
-        __cfaehm__begin_unwind();
+        __cfaehm__throw_terminate(&shared_stack.current_exception);
 }
 
@@ -356 +263 @@
                                         _Unwind_Reason_Code (*matcher)(exception *) =
                                                 MATCHER_FROM_CONTEXT(context);
-                                        int index = matcher(shared_stack.current_exception);
+                                        int index = matcher(&shared_stack.current_exception);
                                         _Unwind_Reason_Code ret = (0 == index)
                                                 ? _URC_CONTINUE_UNWIND : _URC_HANDLER_FOUND;
@@ -452 +359 @@
         // Exception handler
         catch_block( shared_stack.current_handler_index,
-                     shared_stack.current_exception );
+                    &shared_stack.current_exception );
 }