several bugfixes for powerpc continuations

src/compile-powerpc.S

@@ -87,12 +87,12 @@ GLOBAL(vmInvoke):
    
    // copy arguments into place
    li   r16,0
+   addi r18,r1,ARGUMENT_BASE
    b    LOCAL(vmInvoke_argumentTest)
    
 LOCAL(vmInvoke_argumentLoop):
    lwzx r17,r16,r5
-   addi r18,r16,ARGUMENT_BASE
+   stwx r17,r16,r18
-   stwx r17,r18,r1
    addi r16,r16,BYTES_PER_WORD
    
 LOCAL(vmInvoke_argumentTest):
@@ -103,8 +103,7 @@ LOCAL(vmInvoke_argumentTest):
    mtctr r4
    bctrl
 
-.globl GLOBAL(vmInvoke_returnAddress)
+LOCAL(vmInvoke_returnAddress):
-GLOBAL(vmInvoke_returnAddress):
    // restore stack pointer
 	 lwz	r1,0(r1)
 
@@ -116,17 +115,18 @@ GLOBAL(vmInvoke_returnAddress):
 
    lwz  r6,CONTINUATION_LENGTH(r5)
    slwi r6,r6,2
-   subfic r6,r6,-80
+   subfic r7,r6,-80
-   stwux r1,r1,r6
+   stwux r1,r1,r7
 
    addi r7,r5,CONTINUATION_BODY
 
    li   r8,0
+   addi r10,r1,ARGUMENT_BASE
    b    LOCAL(vmInvoke_continuationTest)
 
 LOCAL(vmInvoke_continuationLoop):
    lwzx r9,r7,r8
-   stwx r9,r1,r8
+   stwx r9,r10,r8
    addi r8,r8,4
 
 LOCAL(vmInvoke_continuationTest):
@@ -138,8 +138,7 @@ LOCAL(vmInvoke_continuationTest):
    
 LOCAL(vmInvoke_getPC):
    mflr r10
-   addis r10,r10,ha16(GLOBAL(vmInvoke_returnAddress)-LOCAL(vmInvoke_getPC))
+   la   r10,lo16(LOCAL(vmInvoke_returnAddress)-LOCAL(vmInvoke_getPC))(r10)
-   la   r10,lo16(GLOBAL(vmInvoke_returnAddress)-LOCAL(vmInvoke_getPC))(r10)
    stwx r10,r1,r7
 
    lwz  r7,CONTINUATION_FRAME_POINTER_OFFSET(r5)
@@ -155,7 +154,7 @@ LOCAL(vmInvoke_getPC):
    lwz  r7,THREAD_EXCEPTION(r13)
    cmpwi r7,0
    bne  LOCAL(vmInvoke_handleException)
-   addi r7,r5,CONTINUATION_ADDRESS
+   lwz  r7,CONTINUATION_ADDRESS(r5)
    mtctr r7
    bctr
 
@@ -170,7 +169,7 @@ LOCAL(vmInvoke_handleException):
    lwz  r8,THREAD_EXCEPTION_OFFSET(r13)
    stwx r7,r1,r8
 
-   addi r7,r13,THREAD_EXCEPTION_HANDLER
+   lwz  r7,THREAD_EXCEPTION_HANDLER(r13)
    mtctr r7
    bctr
 
@@ -226,6 +225,7 @@ LOCAL(vmInvoke_return):
 
 .globl GLOBAL(vmJumpAndInvoke)
 GLOBAL(vmJumpAndInvoke):
+#ifdef AVIAN_CONTINUATIONS
    // r3: thread
    // r4: address
    // r5: (unused)
@@ -234,36 +234,50 @@ GLOBAL(vmJumpAndInvoke):
    // r8: arguments
    // r9: frameSize
 
+   // restore (pseudo)-stack pointer (we don't want to touch the real
+   // stack pointer, since we haven't copied the arguments yet)
+   lwz  r6,0(r6)
+
+   // make everything between r1 and r6 one big stack frame while we
+   // shuffle things around
    stw  r6,0(r1)
 
+   // allocate new frame, adding room for callee-saved registers
+   subfic r10,r9,-80
+	 stwux r6,r6,r10
+   
    mr   r13,r3
 
    // copy arguments into place
    li   r9,0
-   addi r10,r6,ARGUMENT_BASE
+   addi r11,r6,ARGUMENT_BASE
    b    LOCAL(vmJumpAndInvoke_argumentTest)
 
 LOCAL(vmJumpAndInvoke_argumentLoop):
-   lwzx r11,r8,r9
+   lwzx r12,r8,r9
-   stwx r11,r10,r9
+   stwx r12,r11,r9
    addi r9,r9,4
 
 LOCAL(vmJumpAndInvoke_argumentTest):
    cmplw r9,r7
    ble  LOCAL(vmJumpAndInvoke_argumentLoop)
 
-   subf r7,r6,r9
+   // the arguments have been copied, so we can set the real stack
-   stw  r6,0(r7)
+   // pointer now
-   mr   r1,r7
+   mr   r1,r6
    
-   // set return address
+   // set return address to vmInvoke_returnAddress
    bl   LOCAL(vmJumpAndInvoke_getPC)
    
 LOCAL(vmJumpAndInvoke_getPC):
    mflr r10
-   addis r10,r10,ha16(GLOBAL(vmInvoke_returnAddress)-LOCAL(vmJumpAndInvoke_getPC))
+   la   r10,lo16(LOCAL(vmInvoke_returnAddress)-LOCAL(vmJumpAndInvoke_getPC))(r10)
-   la   r10,lo16(GLOBAL(vmInvoke_returnAddress)-LOCAL(vmJumpAndInvoke_getPC))(r10)
    mtlr r10
 
    mtctr r4
    bctr
+#else // not AVIAN_CONTINUATIONS
+   // vmJumpAndInvoke should only be called when continuations are
+   // enabled
+   trap
+#endif // not AVIAN_CONTINUATIONS

src/compile.cpp

@@ -1380,7 +1380,7 @@ releaseLock(MyThread* t, object method, void* stack)
 
 void
 findUnwindTarget(MyThread* t, void** targetIp, void** targetBase,
-                 void** targetStack, unsigned* oldArgumentFootprint = 0)
+                 void** targetStack)
 {
   void* ip = t->ip;
   void* base = t->base;
@@ -1427,11 +1427,6 @@ findUnwindTarget(MyThread* t, void** targetIp, void** targetBase,
       *targetStack = static_cast<void**>(stack)
         + t->arch->frameReturnAddressSize();
 
-      if (oldArgumentFootprint) {
-        *oldArgumentFootprint
-          = t->arch->argumentFootprint(methodParameterFootprint(t, target));
-      }
-
       while (Continuations and t->continuation) {
         object c = t->continuation;
 
@@ -1468,7 +1463,7 @@ findUnwindTarget(MyThread* t, void** targetIp, void** targetBase,
 
 object
 makeCurrentContinuation(MyThread* t, void** targetIp, void** targetBase,
-                        void** targetStack, unsigned* oldArgumentFootprint)
+                        void** targetStack)
 {
   void* ip = t->ip;
   void* base = t->base;
@@ -1498,7 +1493,8 @@ makeCurrentContinuation(MyThread* t, void** targetIp, void** targetBase,
       PROTECT(t, method);
 
       void** top = static_cast<void**>(stack)
-        + t->arch->frameReturnAddressSize();
+        + t->arch->frameReturnAddressSize()
+        + t->arch->frameFooterSize();
       unsigned argumentFootprint
         = t->arch->argumentFootprint(methodParameterFootprint(t, target));
       unsigned alignment = t->arch->stackAlignmentInWords();
@@ -1518,9 +1514,11 @@ makeCurrentContinuation(MyThread* t, void** targetIp, void** targetBase,
       object c = makeContinuation
         (t, 0, context, method, ip,
          ((frameSize
+           + t->arch->frameFooterSize()
            + t->arch->returnAddressOffset()
            - t->arch->frameReturnAddressSize()) * BytesPerWord),
          ((frameSize
+           + t->arch->frameFooterSize()
            + t->arch->framePointerOffset() 
            - t->arch->frameReturnAddressSize()) * BytesPerWord),
          totalSize);
@@ -1541,9 +1539,7 @@ makeCurrentContinuation(MyThread* t, void** targetIp, void** targetBase,
       *targetIp = ip;
       *targetBase = base;
       *targetStack = static_cast<void**>(stack)
-        + t->arch->frameReturnAddressSize();
+        + t->arch->frameReturnAddressSize();;
-      *oldArgumentFootprint
-        = t->arch->argumentFootprint(methodParameterFootprint(t, target));
     }
   }
 
@@ -5392,8 +5388,7 @@ compatibleReturnType(MyThread* t, object oldMethod, object newMethod)
 }
 
 void
-jumpAndInvoke(MyThread* t, object method, void* base, void* stack,
+jumpAndInvoke(MyThread* t, object method, void* base, void* stack, ...)
-              unsigned oldArgumentFootprint, ...)
 {
   t->trace->targetMethod = 0;
 
@@ -5405,7 +5400,7 @@ jumpAndInvoke(MyThread* t, object method, void* base, void* stack,
 
   unsigned argumentCount = methodParameterFootprint(t, method);
   uintptr_t arguments[argumentCount];
-  va_list a; va_start(a, oldArgumentFootprint);
+  va_list a; va_start(a, stack);
   for (unsigned i = 0; i < argumentCount; ++i) {
     arguments[i] = va_arg(a, uintptr_t);
   }
@@ -5417,10 +5412,8 @@ jumpAndInvoke(MyThread* t, object method, void* base, void* stack,
      stack,
      argumentCount * BytesPerWord,
      arguments,
-     (oldArgumentFootprint
+     t->arch->alignFrameSize(t->arch->argumentFootprint(argumentCount))
-      - t->arch->argumentFootprint(argumentCount)
+     * BytesPerWord);
-      - t->arch->frameFooterSize()
-      - t->arch->frameReturnAddressSize()) * BytesPerWord);
 }
 
 void
@@ -5527,8 +5520,7 @@ callContinuation(MyThread* t, object continuation, object result,
   void* ip;
   void* base;
   void* stack;
-  unsigned oldArgumentFootprint;
+  findUnwindTarget(t, &ip, &base, &stack);
-  findUnwindTarget(t, &ip, &base, &stack, &oldArgumentFootprint);
 
   switch (action) {
   case Call: {
@@ -5543,7 +5535,7 @@ callContinuation(MyThread* t, object continuation, object result,
     t->continuation = nextContinuation;
 
     jumpAndInvoke
-      (t, rewindMethod(t), base, stack, oldArgumentFootprint,
+      (t, rewindMethod(t), base, stack,
        continuationContextBefore(t, continuationContext(t, nextContinuation)),
        continuation, result, exception);
   } break;
@@ -5564,7 +5556,6 @@ callWithCurrentContinuation(MyThread* t, object receiver)
   void* ip = 0;
   void* base = 0;
   void* stack = 0;
-  unsigned oldArgumentFootprint = 0;
 
   { PROTECT(t, receiver);
 
@@ -5601,16 +5592,13 @@ callWithCurrentContinuation(MyThread* t, object receiver)
       compile(t, ::codeAllocator(t), 0, method);
 
       if (LIKELY(t->exception == 0)) {
-        t->continuation = makeCurrentContinuation
+        t->continuation = makeCurrentContinuation(t, &ip, &base, &stack);
-          (t, &ip, &base, &stack, &oldArgumentFootprint);
       }
     }
   }
 
   if (LIKELY(t->exception == 0)) {
-    jumpAndInvoke
+    jumpAndInvoke(t, method, base, stack, receiver, t->continuation);
-      (t, method, base, stack, oldArgumentFootprint, receiver,
-       t->continuation);
   } else {
     unwind(t);
   }
@@ -5622,7 +5610,6 @@ dynamicWind(MyThread* t, object before, object thunk, object after)
   void* ip = 0;
   void* base = 0;
   void* stack = 0;
-  unsigned oldArgumentFootprint = 0;
 
   { PROTECT(t, before);
     PROTECT(t, thunk);
@@ -5648,8 +5635,7 @@ dynamicWind(MyThread* t, object before, object thunk, object after)
     }
 
     if (LIKELY(t->exception == 0)) {
-      t->continuation = makeCurrentContinuation
+      t->continuation = makeCurrentContinuation(t, &ip, &base, &stack);
-        (t, &ip, &base, &stack, &oldArgumentFootprint);
 
       object newContext = makeContinuationContext
         (t, continuationContext(t, t->continuation), before, after,
@@ -5660,9 +5646,7 @@ dynamicWind(MyThread* t, object before, object thunk, object after)
   }
 
   if (LIKELY(t->exception == 0)) {
-    jumpAndInvoke
+    jumpAndInvoke(t, windMethod(t), base, stack, before, thunk, after);
-      (t, windMethod(t), base, stack, oldArgumentFootprint, before, thunk,
-       after);
   } else {
     unwind(t);
   }