Implements a new API to set a function entry hook for profiling.

src/ia32/code-stubs-ia32.cc

Index: src/ia32/code-stubs-ia32.cc
diff --git a/src/ia32/code-stubs-ia32.cc b/src/ia32/code-stubs-ia32.cc
index afa3e1c568bdfadbe9e3feb88d51b2efaa56118a..7be2b4f65f9d8a5a06c7ec651452f1192f7199e8 100644
--- a/src/ia32/code-stubs-ia32.cc
+++ b/src/ia32/code-stubs-ia32.cc
@@ -7474,6 +7474,38 @@ void StoreArrayLiteralElementStub::Generate(MacroAssembler* masm) {
   __ ret(0);
 }
 
+
+void ProfileEntryHookStub::MaybeCallEntryHook(MacroAssembler* masm) {
+  if (entry_hook_ != NULL) {
+    ProfileEntryHookStub stub;
+    masm->CallStub(&stub);
+  }
+}
+
+
+void ProfileEntryHookStub::Generate(MacroAssembler* masm) {
+  // Ecx is the only volatile register we must save.
+  __ push(ecx);
+
+  // Calculate and push the original stack pointer.
+  __ lea(eax, Operand(esp, kPointerSize));
+  __ push(eax);
+
+  // Calculate and push the function address.
+  __ mov(eax, Operand(eax, 0));
+  __ sub(eax, Immediate(Assembler::kCallInstructionLength));
+  __ push(eax);
+
+  // Call the entry hook.
+  int32_t hook_location = reinterpret_cast<int32_t>(&entry_hook_);
+  __ call(Operand(hook_location, RelocInfo::NONE));
+  __ add(esp, Immediate(2 * kPointerSize));
+
+  // Restore ecx.
+  __ pop(ecx);
+  __ ret(0);
+}
+
 #undef __
 
 } }  // namespace v8::internal