Emit pushes and pops through the virtual frame on ARM. Merging of...

src/codegen-ia32.cc

Index: src/codegen-ia32.cc
===================================================================
--- src/codegen-ia32.cc	(revision 703)
+++ src/codegen-ia32.cc	(working copy)
@@ -267,10 +267,8 @@
         __ int3();
         __ bind(&verified_true);
       }
-
       // Update context local.
       __ mov(frame_->Context(), esi);
-      // Restore the arguments array pointer, if any.
     }
 
     // TODO(1241774): Improve this code:
@@ -310,10 +308,10 @@
     // This section stores the pointer to the arguments object that
     // was allocated and copied into above. If the address was not
     // saved to TOS, we push ecx onto the stack.
-
-    // Store the arguments object.
-    // This must happen after context initialization because
-    // the arguments object may be stored in the context
+    //
+    // Store the arguments object.  This must happen after context
+    // initialization because the arguments object may be stored in the
+    // context.
     if (arguments_object_allocated) {
       ASSERT(scope_->arguments() != NULL);
       ASSERT(scope_->arguments_shadow() != NULL);
@@ -341,18 +339,17 @@
       frame_->Pop();  // Value is no longer needed.
     }
 
-    // Generate code to 'execute' declarations and initialize
-    // functions (source elements). In case of an illegal
-    // redeclaration we need to handle that instead of processing the
-    // declarations.
+    // Generate code to 'execute' declarations and initialize functions
+    // (source elements). In case of an illegal redeclaration we need to
+    // handle that instead of processing the declarations.
     if (scope_->HasIllegalRedeclaration()) {
       Comment cmnt(masm_, "[ illegal redeclarations");
       scope_->VisitIllegalRedeclaration(this);
     } else {
       Comment cmnt(masm_, "[ declarations");
       ProcessDeclarations(scope_->declarations());
-      // Bail out if a stack-overflow exception occurred when
-      // processing declarations.
+      // Bail out if a stack-overflow exception occurred when processing
+      // declarations.
       if (HasStackOverflow()) return;
     }
 
@@ -448,10 +445,11 @@
 
 
 // Loads a value on TOS. If it is a boolean value, the result may have been
-// (partially) translated into branches, or it may have set the condition code
-// register. If force_cc is set, the value is forced to set the condition code
-// register and no value is pushed. If the condition code register was set,
-// has_cc() is true and cc_reg_ contains the condition to test for 'true'.
+// (partially) translated into branches, or it may have set the condition
+// code register. If force_cc is set, the value is forced to set the
+// condition code register and no value is pushed. If the condition code
+// register was set, has_cc() is true and cc_reg_ contains the condition to
+// test for 'true'.
 void CodeGenerator::LoadCondition(Expression* x,
                                   TypeofState typeof_state,
                                   Label* true_target,
@@ -463,6 +461,14 @@
     Visit(x);
   }
   if (force_cc && !has_cc()) {
+    // Convert the TOS value to a boolean in the condition code register.
+    // Visiting an expression may possibly choose neither (a) to leave a
+    // value in the condition code register nor (b) to leave a value in TOS
+    // (eg, by compiling to only jumps to the targets).  In that case the
+    // code generated by ToBoolean is wrong because it assumes the value of
+    // the expression in TOS.  So long as there is always a value in TOS or
+    // the condition code register when control falls through to here (there
+    // is), the code generated by ToBoolean is dead and therefore safe.
     ToBoolean(true_target, false_target);
   }
   ASSERT(has_cc() || !force_cc);
@@ -476,7 +482,6 @@
 
   if (has_cc()) {
     // convert cc_reg_ into a bool
-
     Label loaded, materialize_true;
     __ j(cc_reg_, &materialize_true);
     frame_->Push(Immediate(Factory::false_value()));
@@ -663,7 +668,7 @@
   frame_->Push(eax);  // Undo the pop(eax) from above.
   ToBooleanStub stub;
   __ CallStub(&stub);
-  // Convert result (eax) to condition code.
+  // Convert the result (eax) to condition code.
   __ test(eax, Operand(eax));
 
   ASSERT(not_equal == not_zero);
@@ -2198,7 +2203,6 @@
   frame_->Pop(Operand::StaticVariable(handler_address));
   frame_->Drop(StackHandlerConstants::kSize / kPointerSize - 1);
   // Next_sp popped.
-  // Preserve the TOS in a register across stack manipulation.
   frame_->Push(eax);
 
   // --- Finally block ---