Changeset 76e069f for libcfa

Timestamp:

Jan 11, 2019, 10:54:41 AM (6 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

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

Children:

456834b

Parents:

f23b685

Message:

Implemented stack unwinding on coroutine termination

Location:

libcfa/src/concurrency

Files:

• coroutine.cfa (modified) (5 diffs)
• invoke.c (modified) (2 diffs)
• invoke.h (modified) (1 diff)

libcfa/src/concurrency/coroutine.cfa

@@ -22 +22 @@
 #include <string.h>
 #include <unistd.h>
+// use this define to make unwind.h play nice, definetely a hack
+#define HIDE_EXPORTS
+#include <unwind.h>
+#undef HIDE_EXPORTS
 #include <sys/mman.h>
 }
@@ -29 +33 @@
 #define __CFA_INVOKE_PRIVATE__
 #include "invoke.h"
+
+extern "C" {
+      void _CtxCoroutine_Unwind(struct _Unwind_Exception * storage) __attribute__ ((__noreturn__));
+      static void _CtxCoroutine_UnwindCleanup(_Unwind_Reason_Code, struct _Unwind_Exception *) __attribute__ ((__noreturn__));
+      static void _CtxCoroutine_UnwindCleanup(_Unwind_Reason_Code, struct _Unwind_Exception *) {
+            abort();
+      }
+}
 
 //-----------------------------------------------------------------------------
@@ -67 +79 @@
       starter = NULL;
       last = NULL;
-}
-
-void ^?{}(coroutine_desc& this) {}
+      cancellation = NULL;
+}
+
+void ^?{}(coroutine_desc& this) {
+      if(this.state != Halted) {
+            coroutine_desc * src = TL_GET( this_coroutine );
+            coroutine_desc * dst = &this;
+
+            struct _Unwind_Exception storage;
+            storage.exception_class = -1;
+            storage.exception_cleanup = _CtxCoroutine_UnwindCleanup;
+            this.cancellation = &storage;
+            this.last = src;
+
+              // not resuming self ?
+              if ( src == dst ) {
+                      abort( "Attempt by coroutine %.256s (%p) to terminate itself.\n", src->name, src );
+            }
+
+              CoroutineCtxSwitch( src, dst );
+      }
+}
 
 // Part of the Public API
@@ -105 +136 @@
       // Safety note : This could cause some false positives due to preemption
       verify( TL_GET( preemption_state.enabled ) || TL_GET( this_processor )->do_terminate );
+
+      if( unlikely(src->cancellation != NULL) ) {
+            _CtxCoroutine_Unwind(src->cancellation);
+      }
 } //ctxSwitchDirect
 
@@ -162 +197 @@
       }
 
-      void __leave_coroutine(void) {
+      void __leave_coroutine() {
             coroutine_desc * src = TL_GET( this_coroutine ); // optimization
+            coroutine_desc * starter = src->cancellation != 0 ? src->last : src->starter;
 
             src->state = Halted;
 
-            assertf( src->starter != 0,
+            assertf( starter != 0,
                   "Attempt to suspend/leave coroutine \"%.256s\" (%p) that has never been resumed.\n"
                   "Possible cause is a suspend executed in a member called by a coroutine user rather than by the coroutine main.",
                   src->name, src );
-            assertf( src->starter->state != Halted,
+            assertf( starter->state != Halted,
                   "Attempt by coroutine \"%.256s\" (%p) to suspend/leave back to terminated coroutine \"%.256s\" (%p).\n"
                   "Possible cause is terminated coroutine's main routine has already returned.",
-                  src->name, src, src->starter->name, src->starter );
-
-            CoroutineCtxSwitch( src, src->starter );
+                  src->name, src, starter->name, starter );
+
+            CoroutineCtxSwitch( src, starter );
       }
 }

libcfa/src/concurrency/invoke.c

@@ -17 +17 @@
 #include <stdlib.h>
 #include <stdio.h>
+#include <unwind.h>
 
 #include "invoke.h"
@@ -53 +54 @@
         __leave_coroutine();
         __cabi_abort( "Resumed dead coroutine" );
+}
+
+static _Unwind_Reason_Code _CtxCoroutine_UnwindStop(
+        __attribute((__unused__)) int version,
+        _Unwind_Action actions,
+        __attribute((__unused__)) _Unwind_Exception_Class exceptionClass,
+        __attribute((__unused__)) struct _Unwind_Exception * unwind_exception,
+        __attribute((__unused__)) struct _Unwind_Context * context,
+        __attribute((__unused__)) void * param
+) {
+        if( actions & _UA_END_OF_STACK  ) {
+                // We finished unwinding the coroutine,
+                // leave it
+                __leave_coroutine();
+                __cabi_abort( "Resumed dead coroutine" );
+        }
+        if( actions & _UA_CLEANUP_PHASE ) return _URC_NO_REASON;
+
+        return _URC_FATAL_PHASE2_ERROR;
+}
+
+void _CtxCoroutine_Unwind(struct _Unwind_Exception * storage) __attribute__ ((__noreturn__));
+void _CtxCoroutine_Unwind(struct _Unwind_Exception * storage) {
+        _Unwind_Reason_Code ret = _Unwind_ForcedUnwind( storage, _CtxCoroutine_UnwindStop, NULL );
+        printf("UNWIND ERROR %d after force unwind\n", ret);
+        abort();
 }
 

libcfa/src/concurrency/invoke.h

@@ -80 +80 @@
 
         struct coroutine_desc {
-                struct coStack_t stack;                                                 // stack information of the coroutine
-                const char * name;                                                              // textual name for coroutine/task, initialized by uC++ generated code
-                int errno_;                                                                             // copy of global UNIX variable errno
-                enum coroutine_state state;                                             // current execution status for coroutine
-                struct coroutine_desc * starter;                                // first coroutine to resume this one
-                struct coroutine_desc * last;                                   // last coroutine to resume this one
+                // stack information of the coroutine
+                struct coStack_t stack;
+
+                // textual name for coroutine/task, initialized by uC++ generated code
+                const char * name;
+
+                // copy of global UNIX variable errno
+                int errno_;
+
+                // current execution status for coroutine
+                enum coroutine_state state;
+                // first coroutine to resume this one
+                struct coroutine_desc * starter;
+
+                // last coroutine to resume this one
+                struct coroutine_desc * last;
+
+                // If non-null stack must be unwound with this exception
+                struct _Unwind_Exception * cancellation;
+
         };