remove FrameEvent code from x86.cpp

That code was unused and will be unecessary until we add proper
support for unwinding through tail calls in nextFrame, at which point
it may be reinstated in some form.

src/x86.cpp

@@ -86,7 +86,6 @@ isInt32(intptr_t v)
 
 class Task;
 class AlignmentPadding;
-class FrameEvent;
 
 unsigned
 padding(AlignmentPadding* p, unsigned index, unsigned offset,
@@ -101,8 +100,8 @@ resolved(Context* c, int64_t value);
 class MyBlock: public Assembler::Block {
  public:
   MyBlock(unsigned offset):
-    next(0), firstPadding(0), lastPadding(0), firstFrameEvent(0),
+    next(0), firstPadding(0), lastPadding(0), offset(offset), start(~0),
-    lastFrameEvent(0), offset(offset), start(~0), size(0)
+    size(0)
   { }
 
   virtual unsigned resolve(unsigned start, Assembler::Block* next) {
@@ -115,8 +114,6 @@ class MyBlock: public Assembler::Block {
   MyBlock* next;
   AlignmentPadding* firstPadding;
   AlignmentPadding* lastPadding;
-  FrameEvent* firstFrameEvent;
-  FrameEvent* lastFrameEvent;
   unsigned offset;
   unsigned start;
   unsigned size;
@@ -159,8 +156,7 @@ class Context {
   Context(System* s, Allocator* a, Zone* zone, ArchitectureContext* ac):
     s(s), zone(zone), client(0), code(s, a, 1024), tasks(0), result(0),
     firstBlock(new (zone->allocate(sizeof(MyBlock))) MyBlock(0)),
-    lastBlock(firstBlock), firstFrameEvent(0), lastFrameEvent(0),
+    lastBlock(firstBlock), ac(ac)
-    ac(ac), frameEventCount(0)
   { }
 
   System* s;
@@ -171,10 +167,7 @@ class Context {
   uint8_t* result;
   MyBlock* firstBlock;
   MyBlock* lastBlock;
-  FrameEvent* firstFrameEvent;
-  FrameEvent* lastFrameEvent;
   ArchitectureContext* ac;
-  unsigned frameEventCount;
 };
 
 void NO_RETURN
@@ -461,39 +454,6 @@ padding(AlignmentPadding* p, unsigned start, unsigned offset,
   return padding;
 }
 
-class FrameEvent {
- public:
-  FrameEvent(Context* c, Promise* offset):
-    c(c), next(0), offset(offset)
-  { }
-
-  Context* c;
-  FrameEvent* next;
-  Promise* offset;
-};
-
-void
-appendFrameEvent(Context* c, MyBlock* b, Promise* offset)
-{
-  FrameEvent* e = new (c->zone->allocate(sizeof(FrameEvent)))
-    FrameEvent(c, offset);
-
-  if (b->firstFrameEvent) {
-    b->lastFrameEvent->next = e;
-  } else {
-    b->firstFrameEvent = e;
-  }
-  b->lastFrameEvent = e;
-
-  ++ c->frameEventCount;
-}
-
-void
-appendFrameEvent(Context* c)
-{
-  appendFrameEvent(c, c->lastBlock, offset(c));
-}
-
 extern "C" bool
 detectFeature(unsigned ecx, unsigned edx);
 
@@ -3524,8 +3484,6 @@ class MyAssembler: public Assembler {
   {
     if (TailCalls) {
       if (offset) {
-        appendFrameEvent(&c);
-
         Register tmp(c.client->acquireTemporary());
       
         unsigned baseSize = UseFramePointer ? 1 : 0;
@@ -3583,8 +3541,6 @@ class MyAssembler: public Assembler {
     assert(&c, (argumentFootprint % StackAlignmentInWords) == 0);
 
     if (TailCalls and argumentFootprint > StackAlignmentInWords) {
-      appendFrameEvent(&c);
-
       Register returnAddress(rcx);
       popR(&c, BytesPerWord, &returnAddress);
 
@@ -3660,15 +3616,6 @@ class MyAssembler: public Assembler {
     c.result = dst;
     
     for (MyBlock* b = c.firstBlock; b; b = b->next) {
-      if (b->firstFrameEvent) {
-        if (c.firstFrameEvent) {
-          c.lastFrameEvent->next = b->firstFrameEvent;
-        } else {
-          c.firstFrameEvent = b->firstFrameEvent;
-        }
-        c.lastFrameEvent = b->lastFrameEvent;
-      }
-
       unsigned index = 0;
       unsigned padding = 0;
       for (AlignmentPadding* p = b->firstPadding; p; p = p->next) {