Second attempt: Improve our type feedback by recogizining never-executed IC c...

src/ia32/full-codegen-ia32.cc

Index: src/ia32/full-codegen-ia32.cc
===================================================================
--- src/ia32/full-codegen-ia32.cc	(revision 6011)
+++ src/ia32/full-codegen-ia32.cc	(working copy)
@@ -41,8 +41,61 @@
 namespace v8 {
 namespace internal {
 
+
 #define __ ACCESS_MASM(masm_)
 
+
+class JumpPatchSite BASE_EMBEDDED {
+ public:
+  explicit JumpPatchSite(MacroAssembler* masm)
+      : masm_(masm) {
+#ifdef DEBUG
+    info_emitted_ = false;
+#endif
+  }
+
+  ~JumpPatchSite() {
+    ASSERT(patch_site_.is_bound() == info_emitted_);
+  }
+
+  void EmitJumpIfNotSmi(Register reg, NearLabel* target) {
+    __ test(reg, Immediate(kSmiTagMask));
+    EmitJump(not_carry, target);   // Always taken before patched.
+  }
+
+  void EmitJumpIfSmi(Register reg, NearLabel* target) {
+    __ test(reg, Immediate(kSmiTagMask));
+    EmitJump(carry, target);  // Never taken before patched.
+  }
+
+  void EmitPatchInfo() {
+    int delta_to_patch_site = masm_->SizeOfCodeGeneratedSince(&patch_site_);
+    ASSERT(is_int8(delta_to_patch_site));
+    __ test(eax, Immediate(delta_to_patch_site));
+#ifdef DEBUG
+    info_emitted_ = true;
+#endif
+  }
+
+  bool is_bound() const { return patch_site_.is_bound(); }
+
+ private:
+  // jc will be patched with jz, jnc will become jnz.
+  void EmitJump(Condition cc, NearLabel* target) {
+    ASSERT(!patch_site_.is_bound() && !info_emitted_);
+    ASSERT(cc == carry || cc == not_carry);
+    __ bind(&patch_site_);
+    __ j(cc, target);
+  }
+
+  MacroAssembler* masm_;
+  Label patch_site_;
+#ifdef DEBUG
+  bool info_emitted_;
+#endif
+};
+
+
 // Generate code for a JS function.  On entry to the function the receiver
 // and arguments have been pushed on the stack left to right, with the
 // return address on top of them.  The actual argument count matches the
@@ -715,12 +768,13 @@
     // Perform the comparison as if via '==='.
     __ mov(edx, Operand(esp, 0));  // Switch value.
     bool inline_smi_code = ShouldInlineSmiCase(Token::EQ_STRICT);
+    JumpPatchSite patch_site(masm_);
     if (inline_smi_code) {
       NearLabel slow_case;
       __ mov(ecx, edx);
       __ or_(ecx, Operand(eax));
-      __ test(ecx, Immediate(kSmiTagMask));
-      __ j(not_zero, &slow_case, not_taken);
+      patch_site.EmitJumpIfNotSmi(ecx, &slow_case);
+
       __ cmp(edx, Operand(eax));
       __ j(not_equal, &next_test);
       __ Drop(1);  // Switch value is no longer needed.
@@ -730,9 +784,8 @@
 
     // Record position before stub call for type feedback.
     SetSourcePosition(clause->position());
-
     Handle<Code> ic = CompareIC::GetUninitialized(Token::EQ_STRICT);
-    __ call(ic, RelocInfo::CODE_TARGET);
+    EmitCallIC(ic, &patch_site);
 
     __ test(eax, Operand(eax));
     __ j(not_equal, &next_test);
@@ -1556,12 +1609,11 @@
                                            OverwriteMode mode,
                                            bool left_is_constant_smi,
                                            Smi* value) {
-  NearLabel call_stub;
-  Label done;
+  NearLabel call_stub, done;
   __ add(Operand(eax), Immediate(value));
   __ j(overflow, &call_stub);
-  __ test(eax, Immediate(kSmiTagMask));
-  __ j(zero, &done);
+  JumpPatchSite patch_site(masm_);
+  patch_site.EmitJumpIfSmi(eax, &done);
 
   // Undo the optimistic add operation and call the shared stub.
   __ bind(&call_stub);
@@ -1574,7 +1626,8 @@
     __ mov(edx, eax);
     __ mov(eax, Immediate(value));
   }
-  __ CallStub(&stub);
+  EmitCallIC(stub.GetCode(), &patch_site);
+
   __ bind(&done);
   context()->Plug(eax);
 }
@@ -1584,7 +1637,7 @@
                                            OverwriteMode mode,
                                            bool left_is_constant_smi,
                                            Smi* value) {
-  Label call_stub, done;
+  NearLabel call_stub, done;
   if (left_is_constant_smi) {
     __ mov(ecx, eax);
     __ mov(eax, Immediate(value));
@@ -1593,8 +1646,8 @@
     __ sub(Operand(eax), Immediate(value));
   }
   __ j(overflow, &call_stub);
-  __ test(eax, Immediate(kSmiTagMask));
-  __ j(zero, &done);
+  JumpPatchSite patch_site(masm_);
+  patch_site.EmitJumpIfSmi(eax, &done);
 
   __ bind(&call_stub);
   if (left_is_constant_smi) {
@@ -1607,7 +1660,8 @@
   }
   Token::Value op = Token::SUB;
   TypeRecordingBinaryOpStub stub(op, mode);
-  __ CallStub(&stub);
+  EmitCallIC(stub.GetCode(), &patch_site);
+
   __ bind(&done);
   context()->Plug(eax);
 }
@@ -1617,19 +1671,21 @@
                                                Token::Value op,
                                                OverwriteMode mode,
                                                Smi* value) {
-  Label call_stub, smi_case, done;
+  NearLabel call_stub, smi_case, done;
   int shift_value = value->value() & 0x1f;
 
-  __ test(eax, Immediate(kSmiTagMask));
-  __ j(zero, &smi_case);
+  JumpPatchSite patch_site(masm_);
+  patch_site.EmitJumpIfSmi(eax, &smi_case);
 
+  // Call stub.
   __ bind(&call_stub);
   __ mov(edx, eax);
   __ mov(eax, Immediate(value));
   TypeRecordingBinaryOpStub stub(op, mode);
-  __ CallStub(&stub);
+  EmitCallIC(stub.GetCode(), &patch_site);
   __ jmp(&done);
 
+  // Smi case.
   __ bind(&smi_case);
   switch (op) {
     case Token::SHL:
@@ -1679,17 +1735,19 @@
                                              Token::Value op,
                                              OverwriteMode mode,
                                              Smi* value) {
-  Label smi_case, done;
-  __ test(eax, Immediate(kSmiTagMask));
-  __ j(zero, &smi_case);
+  NearLabel smi_case, done;
 
+  JumpPatchSite patch_site(masm_);
+  patch_site.EmitJumpIfSmi(eax, &smi_case);
+
   // The order of the arguments does not matter for bit-ops with a
   // constant operand.
   __ mov(edx, Immediate(value));
   TypeRecordingBinaryOpStub stub(op, mode);
-  __ CallStub(&stub);
+  EmitCallIC(stub.GetCode(), &patch_site);
   __ jmp(&done);
 
+  // Smi case.
   __ bind(&smi_case);
   switch (op) {
     case Token::BIT_OR:
@@ -1757,19 +1815,20 @@
 
   // Do combined smi check of the operands. Left operand is on the
   // stack. Right operand is in eax.
-  Label done, stub_call, smi_case;
+  NearLabel done, smi_case, stub_call;
   __ pop(edx);
   __ mov(ecx, eax);
   __ or_(eax, Operand(edx));
-  __ test(eax, Immediate(kSmiTagMask));
-  __ j(zero, &smi_case);
+  JumpPatchSite patch_site(masm_);
+  patch_site.EmitJumpIfSmi(eax, &smi_case);
 
   __ bind(&stub_call);
   __ mov(eax, ecx);
   TypeRecordingBinaryOpStub stub(op, mode);
-  __ CallStub(&stub);
+  EmitCallIC(stub.GetCode(), &patch_site);
   __ jmp(&done);
 
+  // Smi case.
   __ bind(&smi_case);
   __ mov(eax, edx);  // Copy left operand in case of a stub call.
 
@@ -1848,7 +1907,7 @@
                                      OverwriteMode mode) {
   __ pop(edx);
   TypeRecordingBinaryOpStub stub(op, mode);
-  __ CallStub(&stub);
+  EmitCallIC(stub.GetCode(), NULL);  // NULL signals no inlined smi code.
   context()->Plug(eax);
 }
 
@@ -3713,8 +3772,9 @@
   }
 
   // Inline smi case if we are in a loop.
-  NearLabel stub_call;
-  Label done;
+  NearLabel stub_call, done;
+  JumpPatchSite patch_site(masm_);
+
   if (ShouldInlineSmiCase(expr->op())) {
     if (expr->op() == Token::INC) {
       __ add(Operand(eax), Immediate(Smi::FromInt(1)));
@@ -3724,8 +3784,8 @@
     __ j(overflow, &stub_call);
     // We could eliminate this smi check if we split the code at
     // the first smi check before calling ToNumber.
-    __ test(eax, Immediate(kSmiTagMask));
-    __ j(zero, &done);
+    patch_site.EmitJumpIfSmi(eax, &done);
+
     __ bind(&stub_call);
     // Call stub. Undo operation first.
     if (expr->op() == Token::INC) {
@@ -3743,7 +3803,7 @@
   __ mov(eax, Immediate(Smi::FromInt(1)));
   TypeRecordingBinaryOpStub stub(expr->binary_op(),
                                  NO_OVERWRITE);
-  __ CallStub(&stub);
+  EmitCallIC(stub.GetCode(), &patch_site);
   __ bind(&done);
 
   // Store the value returned in eax.
@@ -4016,21 +4076,22 @@
       }
 
       bool inline_smi_code = ShouldInlineSmiCase(op);
+      JumpPatchSite patch_site(masm_);
       if (inline_smi_code) {
         NearLabel slow_case;
         __ mov(ecx, Operand(edx));
         __ or_(ecx, Operand(eax));
-        __ test(ecx, Immediate(kSmiTagMask));
-        __ j(not_zero, &slow_case, not_taken);
+        patch_site.EmitJumpIfNotSmi(ecx, &slow_case);
         __ cmp(edx, Operand(eax));
         Split(cc, if_true, if_false, NULL);
         __ bind(&slow_case);
       }
 
       // Record position and call the compare IC.
+      SetSourcePosition(expr->position());
       Handle<Code> ic = CompareIC::GetUninitialized(op);
-      SetSourcePosition(expr->position());
-      __ call(ic, RelocInfo::CODE_TARGET);
+      EmitCallIC(ic, &patch_site);
+
       PrepareForBailoutBeforeSplit(TOS_REG, true, if_true, if_false);
       __ test(eax, Operand(eax));
       Split(cc, if_true, if_false, fall_through);
@@ -4134,6 +4195,16 @@
 }
 
 
+void FullCodeGenerator::EmitCallIC(Handle<Code> ic, JumpPatchSite* patch_site) {
+  __ call(ic, RelocInfo::CODE_TARGET);
+  if (patch_site != NULL && patch_site->is_bound()) {
+    patch_site->EmitPatchInfo();
+  } else {
+    __ nop();  // Signals no inlined code.
+  }
+}
+
+
 void FullCodeGenerator::StoreToFrameField(int frame_offset, Register value) {
   ASSERT_EQ(POINTER_SIZE_ALIGN(frame_offset), frame_offset);
   __ mov(Operand(ebp, frame_offset), value);