Embedded constant pools.

src/frames.cc

Index: src/frames.cc
diff --git a/src/frames.cc b/src/frames.cc
index f52b3ce4e47a1bf0fd099723fb36d0f0ac604128..d59fc1b7475764bae4888c286dcd661459a4428a 100644
--- a/src/frames.cc
+++ b/src/frames.cc
@@ -321,9 +321,6 @@ bool SafeStackFrameIterator::IsValidExitFrame(Address fp) const {
   if (!IsValidStackAddress(sp)) return false;
   StackFrame::State state;
   ExitFrame::FillState(fp, sp, &state);
-  if (!IsValidStackAddress(reinterpret_cast<Address>(state.pc_address))) {
-    return false;
-  }

[rmcilroy, 2015/05/20 14:32:11]

Why are you removing this?

[MTBrandyberry, 2015/05/20 22:28:22]

By definition, the an exit frame's pc_address is above sp (see
ExitFrame::FillState).  Thus, this check always fails.

This appears to be harmless for frames without the constant pool slot, but
causes real issues otherwise.  IIRC, it leads to clobbering constant pool
register upon return in some cases.

   return *state.pc_address != NULL;
 }
 
@@ -385,9 +382,8 @@ static bool GcSafeCodeContains(HeapObject* object, Address addr);
 #endif
 
 
-void StackFrame::IteratePc(ObjectVisitor* v,
-                           Address* pc_address,
-                           Code* holder) {
+void StackFrame::IteratePc(ObjectVisitor* v, Address* pc_address,
+                           Address* constant_pool_address, Code* holder) {
   Address pc = *pc_address;
   DCHECK(GcSafeCodeContains(holder, pc));
   unsigned pc_offset = static_cast<unsigned>(pc - holder->instruction_start());
@@ -397,6 +393,9 @@ void StackFrame::IteratePc(ObjectVisitor* v,
     holder = reinterpret_cast<Code*>(code);
     pc = holder->instruction_start() + pc_offset;
     *pc_address = pc;
+    if (FLAG_enable_embedded_constant_pool && constant_pool_address) {
+      *constant_pool_address = holder->constant_pool();
+    }
   }
 }
 
@@ -506,7 +505,7 @@ void ExitFrame::ComputeCallerState(State* state) const {
   state->fp = Memory::Address_at(fp() + ExitFrameConstants::kCallerFPOffset);
   state->pc_address = ResolveReturnAddressLocation(
       reinterpret_cast<Address*>(fp() + ExitFrameConstants::kCallerPCOffset));
-  if (FLAG_enable_ool_constant_pool) {
+  if (FLAG_enable_embedded_constant_pool) {
     state->constant_pool_address = reinterpret_cast<Address*>(
         fp() + ExitFrameConstants::kConstantPoolOffset);
   }
@@ -521,11 +520,8 @@ void ExitFrame::SetCallerFp(Address caller_fp) {
 void ExitFrame::Iterate(ObjectVisitor* v) const {
   // The arguments are traversed as part of the expression stack of
   // the calling frame.
-  IteratePc(v, pc_address(), LookupCode());
+  IteratePc(v, pc_address(), constant_pool_address(), LookupCode());
   v->VisitPointer(&code_slot());
-  if (FLAG_enable_ool_constant_pool) {
-    v->VisitPointer(&constant_pool_slot());
-  }
 }
 
 
@@ -553,8 +549,11 @@ void ExitFrame::FillState(Address fp, Address sp, State* state) {
   state->fp = fp;
   state->pc_address = ResolveReturnAddressLocation(
       reinterpret_cast<Address*>(sp - 1 * kPCOnStackSize));
-  state->constant_pool_address =
-      reinterpret_cast<Address*>(fp + ExitFrameConstants::kConstantPoolOffset);
+  // The constant pool recorded in the exit frame is not associated
+  // with the pc in this state (the return address into a C entry
+  // stub).  ComputeCallerState will retrieve the constant pool
+  // together with the associated caller pc.
+  state->constant_pool_address = NULL;
 }
 
 
@@ -663,7 +662,7 @@ void StandardFrame::IterateCompiledFrame(ObjectVisitor* v) const {
   }
 
   // Visit the return address in the callee and incoming arguments.
-  IteratePc(v, pc_address(), code);
+  IteratePc(v, pc_address(), constant_pool_address(), code);
 
   // Visit the context in stub frame and JavaScript frame.
   // Visit the function in JavaScript frame.
@@ -1285,7 +1284,7 @@ void ArgumentsAdaptorFrame::Print(StringStream* accumulator,
 
 
 void EntryFrame::Iterate(ObjectVisitor* v) const {
-  IteratePc(v, pc_address(), LookupCode());
+  IteratePc(v, pc_address(), constant_pool_address(), LookupCode());
 }
 
 
@@ -1299,7 +1298,7 @@ void StandardFrame::IterateExpressions(ObjectVisitor* v) const {
 
 void JavaScriptFrame::Iterate(ObjectVisitor* v) const {
   IterateExpressions(v);
-  IteratePc(v, pc_address(), LookupCode());
+  IteratePc(v, pc_address(), constant_pool_address(), LookupCode());
 }
 
 
@@ -1307,7 +1306,7 @@ void InternalFrame::Iterate(ObjectVisitor* v) const {
   // Internal frames only have object pointers on the expression stack
   // as they never have any arguments.
   IterateExpressions(v);
-  IteratePc(v, pc_address(), LookupCode());
+  IteratePc(v, pc_address(), constant_pool_address(), LookupCode());
 }
 
 
@@ -1320,7 +1319,7 @@ void StubFailureTrampolineFrame::Iterate(ObjectVisitor* v) const {
   const int offset = StandardFrameConstants::kLastObjectOffset;
   limit = &Memory::Object_at(fp() + offset) + 1;
   v->VisitPointers(base, limit);
-  IteratePc(v, pc_address(), LookupCode());
+  IteratePc(v, pc_address(), constant_pool_address(), LookupCode());
 }