Changeset 482

Timestamp:

01/07/11 22:11:15 (14 years ago)

Author:

Don Clugston

Message:

1513 try/catch/finally misbehavior on windows

This one's for Brad.

Files:

• trunk/src/rt/deh.d (modified) (5 diffs)

trunk/src/rt/deh.d

@@ -170 +170 @@
-    and gives a corrected form, but it's for x86_64 only.
-  http://www.microsoft.com/msj/0197/exception/exception.aspx says that it was
-    undocumented in 1997.
-  The pExceptRec is what will be passed to the language specific handler.
-  According to MSJ, the targetIp value is unused on Win32.
-  The 'valueForEAX' parameter should always be 0.
- */
-extern(Windows)
-void RtlUnwind(void *targetFrame, void *targetIp, EXCEPTION_RECORD *pExceptRec, void *valueForEAX);
-
-alias int function() fp_t; // function pointer in ambient memory model
-
-extern(C)
-{ 
-extern __gshared DWORD _except_list; // This is just FS:[0]
-}
-
-extern(C)
-{
-void _d_setUnhandled(Object);
-void _d_createTrace(Object);
-int _d_isbaseof(ClassInfo b, ClassInfo c);
@@ -223 +221 @@
-is a 'unwind' call. All of the intervening finally blocks are run at this time.
-The complicated case is a CollidedException, which happens when a finally block
-throws an exception. The new exception needs to either replace the old one, or
-be chained to the old one.
-
-The other complexity comes from the fact that a single function may have
-multiple try/catch/finally blocks. Hence, there's a 'handler table' created for
-each function which uses exceptions.
-+/
-
+extern(C)
+{
+    alias 
+    EXCEPTION_DISPOSITION function (
+            EXCEPTION_RECORD *exceptionRecord,
+            DEstablisherFrame *frame,
+            CONTEXT *context,
+            void *dispatcherContext) LanguageSpecificHandler;
+}
+
+
-// The layout of DEstablisherFrame is the same for C++
-
-struct DEstablisherFrame
-{
-void *prev;        
-void *handler;             
-
-
+DEstablisherFrame *prev;
+LanguageSpecificHandler handler;
+     
+     
-};
-
-struct DHandlerInfo
-{
-    int prev_index;             // previous table index
-    uint cioffset;              // offset to DCatchInfo data from start of table (!=0 if try-catch)
-    void *finally_code;         // pointer to finally code to execute
-                                // (!=0 if try-finally)
-};
-
@@ -294 +301 @@
-            CONTEXT *context,
-            void *dispatcherContext)
-{
-    DHandlerTable *handlerTable;
-
-    asm { mov handlerTable,EAX; }
-
-    if (exceptionRecord.ExceptionFlags & EXCEPTION_UNWIND)
-    {
-         // Call all the finally blocks in this frame
-
+, &unwindCollisionExceptionHandler
-    }
-    else
-    {
-        // Jump to catch block if matching one is found
-        int ndx,prev_ndx,i;
-        DHandlerInfo *phi;
-        DCatchInfo *pci;
-        DCatchBlock *pcb;
-        uint ncatches;              // number of catches in the current handler
-        Object pti;
@@ -352 +359 @@
-                        // Initialize catch variable
-                        regebp = cast(int)&frame.ebp;              // EBP for this frame
-                        *cast(Object *)(regebp + (pcb.bpoffset)) = pti;
-
-                        _d_setUnhandled(pti);
-
-                        // Have system call all finally blocks in intervening frames
-                        _d_global_unwind(frame, exceptionRecord);
-
-                        // Call all the finally blocks skipped in this frame
-
+, &searchCollisionExceptionHandler
-
-                        _d_setUnhandled(null);
-
-                        frame.table_index = prev_ndx;  // we are out of this handler
-
-                        // Jump to catch block. Does not return.
-                        {
-                            uint catch_esp;
-
-
-
+
+
-                            catch_esp = regebp - handlerTable.espoffset - fp_t.sizeof;
-                            asm
-                            {
-                                mov     EAX,catch_esp;
-                                mov     ECX,catch_addr;
-                                mov     [EAX],ECX;
-                                mov     EBP,regebp;
-                                mov     ESP,EAX;         // reset stack
-                                ret;                     // jump to catch block
-                            }
@@ -512 +518 @@
-*/
-        // convert all other exception codes into a Win32Exception
-        default:
-            pti = new Error("Win32 Exception");
-            break;
-    }
-    _d_createTrace(pti);
-    return pti;
-}
-
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-
-extern(C)
-EXCEPTION_DISPOSITION unwindCollisionExceptionHandler(
-            EXCEPTION_RECORD *exceptionRecord,
-            DEstablisherFrame *frame,
-            CONTEXT *context,
-            void *dispatcherContext)
-{
-    if (!(exceptionRecord.ExceptionFlags & EXCEPTION_UNWIND)) 
-        return EXCEPTION_DISPOSITION.ExceptionContinueSearch;
-// An exception has been thrown during unwinding (eg, a throw statement
-  was encountered inside a finally clause)
- The target for unwinding needs to change. 
-Based on the code for RtlUnwind in http://www.microsoft.com/msj/0197/exception/exception.aspx,
-the dispatcherContext is used to set the EXCEPTION_REGISTRATION to be used from now on
-DEstablisherFrame **)dispatcherContext) = frame
+
+An exception has been thrown during unwinding
+It happened during the UNWIND phase.
+We need to cancel the unwind pass, AND we need to cancel the search
+pass that initiated the unwind. So, we need to restart from 'frame.prev'
+void **)dispatcherContext) = frame.prev
-    return EXCEPTION_DISPOSITION.ExceptionCollidedUnwind;
-}
-
-/**************************************
- * Call finally blocks in the current stack frame until stop_index.
- * This is roughly equivalent to _local_unwind() for C in \src\win32\ehsup.c
- */
-extern(C)
-void _d_local_unwind(DHandlerTable *handler_table,
-
+, LanguageSpecificHandler collisionHandler
-{
-    DHandlerInfo *phi;
-    DCatchInfo *pci;
-    int i;
-    // Set up a special exception handler to catch double-fault exceptions.
-    asm
-    {
-        push    dword ptr -1;
-        push    dword ptr 0;
-offset unwindCollisionExcept
+collis
-        push    dword ptr FS:_except_list;
-        mov     FS:_except_list,ESP;
-    }
-    for (i = frame.table_index; i != -1 && i != stop_index; i = phi.prev_index)
-    {
-        phi = &handler_table.handler_info[i];
-        if (phi.finally_code)
-        {
-            // Note that it is unnecessary to adjust the ESP, as the finally block
-            // accesses all items on the stack as relative to EBP.