Changeset b7898ac

Timestamp:

Dec 18, 2023, 12:24:06 PM (4 months ago)

Author:

Andrew Beach <ajbeach@…>

Branches:

master

Children:

9fba8e6

Parents:

5546eee4

Message:

Another attempt at fixing execptions. It is very close to the last attempt but the offsets have been updated and checked.

Files:

• libcfa/src/exception.c (modified) (6 diffs)
• libcfa/src/exception.h (modified) (2 diffs)
• src/ControlStruct/ExceptTranslate.cpp (modified) (1 diff)

libcfa/src/exception.c

@@ -55 +55 @@
 }
 
+struct __cfaehm_base_exception_t * __cfaehm_get_current_termination(void) {
+        return this_exception_context()->current_exception;
+}
+
 
 // RESUMPTION ================================================================
@@ -309 +313 @@
                 struct _Unwind_Context * unwind_context)
 {
-        //! __cfadbg_print_safe(exception, "CFA: 0x%lx\n", _Unwind_GetCFA(unwind_context));
+        __cfadbg_print_safe(exception, "CFA: 0x%p\n", (void*)_Unwind_GetCFA(unwind_context));
         __cfadbg_print_safe(exception, "Personality function (%d, %x, %llu, %p, %p):",
                         version, actions, exception_class, unwind_exception, unwind_context);
@@ -411 +415 @@
                                 _Unwind_Word match_pos =
 #                               if defined( __x86_64 )
-                                    _Unwind_GetCFA(unwind_context) + 8;
+                                        _Unwind_GetCFA(unwind_context);
 #                               elif defined( __i386 )
-                                    _Unwind_GetCFA(unwind_context) + 24;
+                                        _Unwind_GetCFA(unwind_context) + 20;
 #                               elif defined( __ARM_ARCH )
-                                    _Unwind_GetCFA(unwind_context) + 40;
+                                        _Unwind_GetCFA(unwind_context) + 16;
 #                               endif
+                                //! printf("match_pos: %p\n", (void*)match_pos);
+                                //! fflush(stdout);
                                 int (*matcher)(exception_t *) = *(int(**)(exception_t *))match_pos;
 
@@ -479 +485 @@
 // and simply linked from libcfa but there is one problem left, see the exception table for details
 __attribute__((noinline))
-void __cfaehm_try_terminate(void (*try_block)(),
-                void (*catch_block)(int index, exception_t * except),
+int __cfaehm_try_terminate(void (*try_block)(),
                 __attribute__((unused)) int (*match_block)(exception_t * except)) {
         //! volatile int xy = 0;
-        //! printf("%p %p %p %p\n", &try_block, &catch_block, &match_block, &xy);
+        //! printf("%p %p %p\n", &try_block, &match_block, &xy);
+        //! fflush(stdout);
 
         // Setup the personality routine and exception table.
@@ -507 +513 @@
 
         // Normal return for when there is no throw.
-        return;
+        return 0;
 
         // Exceptionnal path
@@ -518 +524 @@
         asm volatile (".CATCH:");
 
-        // Exception handler
-        // Note: Saving the exception context on the stack breaks termination exceptions.
-        catch_block( EXCEPT_TO_NODE( this_exception_context()->current_exception )->handler_index,
-                     this_exception_context()->current_exception );
+        return EXCEPT_TO_NODE( this_exception_context()->current_exception )->handler_index;
 }
 

libcfa/src/exception.h

@@ -44 +44 @@
 
 
+struct __cfaehm_base_exception_t * __cfaehm_get_current_termination(void);
+
+
 void __cfaehm_cancel_stack(exception_t * except) __attribute__((noreturn));
 
@@ -57 +60 @@
 
 // Function catches termination exceptions.
-void __cfaehm_try_terminate(
+int __cfaehm_try_terminate(
         void (*try_block)(),
-        void (*catch_block)(int index, exception_t * except),
         int (*match_block)(exception_t * except));
 

src/ControlStruct/ExceptTranslate.cpp

@@ -482 +482 @@
                 ast::FunctionDecl * terminate_catch,
                 ast::FunctionDecl * terminate_match ) {
-        // { __cfaehm_try_terminate(`try`, `catch`, `match`); }
-
-        ast::UntypedExpr * caller = new ast::UntypedExpr(loc, new ast::NameExpr(loc,
-                "__cfaehm_try_terminate" ) );
-        caller->args.push_back( new ast::VariableExpr(loc, try_wrapper ) );
-        caller->args.push_back( new ast::VariableExpr(loc, terminate_catch ) );
-        caller->args.push_back( new ast::VariableExpr(loc, terminate_match ) );
-
-        ast::CompoundStmt * callStmt = new ast::CompoundStmt(loc);
-        callStmt->push_back( new ast::ExprStmt( loc, caller ) );
-        return callStmt;
+        // {
+        //     int __handler_index = __cfaehm_try_terminate(`try`, `match`);
+        //     if ( __handler_index ) {
+        //         `catch`( __handler_index, __cfaehm_get_current_termination() );
+        //     }
+        // }
+
+        ast::ObjectDecl * index = new ast::ObjectDecl( loc, "__handler_index",
+                new ast::BasicType( ast::BasicType::SignedInt ),
+                new ast::SingleInit( loc,
+                        new ast::UntypedExpr( loc,
+                                new ast::NameExpr( loc, "__cfaehm_try_terminate" ),
+                                {
+                                        new ast::VariableExpr( loc, try_wrapper ),
+                                        new ast::VariableExpr( loc, terminate_match ),
+                                }
+                        )
+                )
+        );
+
+        return new ast::CompoundStmt( loc, {
+                new ast::DeclStmt( loc, index ),
+                new ast::IfStmt( loc,
+                        new ast::VariableExpr( loc, index ),
+                        new ast::ExprStmt( loc,
+                                new ast::UntypedExpr( loc,
+                                        new ast::VariableExpr( loc, terminate_catch ),
+                                        {
+                                                new ast::VariableExpr( loc, index ),
+                                                new ast::UntypedExpr( loc,
+                                                        new ast::NameExpr( loc, "__cfaehm_get_current_termination" )
+                                                ),
+                                        }
+                                )
+                        )
+                ),
+        } );
 }