ARM: Add type-feedback recording for compare...

src/arm/full-codegen-arm.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 27 matching lines @@
 #include "scopes.h"
 #include "stub-cache.h"
 
 #include "arm/code-stubs-arm.h"
 
 namespace v8 {
 namespace internal {
 
 #define __ ACCESS_MASM(masm_)
 
+
+// A patch site is a location in the code which it is possible to patch. This
+// class has a number of methods the emit the code which is patchable and the

[Alexandre, 2011/02/09 13:57:16]

typo: "the emit the code" -> "to emit the code" ?

[Søren Thygesen Gjesse, 2011/02/09 14:48:28]

Done.

+// method EmitPatchInfo to record a marker back to the patchable code. This
+// marker is a cmp rx, #yyy instruction, and x * 0x00000fff + yyy (raw 12 bit
+// immediate value is used) is the delta from the pc to the first instruction of
+// the patchable code.
+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_);
+  }
+
+  // When initially emitting this ensure that a jump is always generated to skip
+  // the inlined smi code.
+  void EmitJumpIfNotSmi(Register reg, Label* target) {
+    ASSERT(!patch_site_.is_bound() && !info_emitted_);
+    __ bind(&patch_site_);
+    __ cmp(reg, Operand(reg));
+    // Don't use b(al, ...) as that might emit the constant pool right after the
+    // branch. After patching when the branch is no longer unconditional
+    // execution can continue into the constant pool.
+    __ b(eq, target);  // Always taken before patched.
+  }
+
+  // When initially emitting this ensure that a jump is never generated to skip
+  // the inlined smi code.
+  void EmitJumpIfSmi(Register reg, Label* target) {
+    ASSERT(!patch_site_.is_bound() && !info_emitted_);
+    __ bind(&patch_site_);
+    __ cmp(reg, Operand(reg));
+    __ b(ne, target);  // Never taken before patched.
+  }
+
+  void EmitPatchInfo() {
+    int delta_to_patch_site = masm_->InstructionsGeneratedSince(&patch_site_);
+    Register reg;
+    reg.set_code(delta_to_patch_site / kOff12Mask);
+    __ cmp_raw_immediate(r0, delta_to_patch_site % kOff12Mask);

[Karl Klose, 2011/02/09 14:35:30]

The destination register of the cmp should be reg.

[Søren Thygesen Gjesse, 2011/02/09 14:48:28]

Good catch, fixed.

+#ifdef DEBUG
+    info_emitted_ = true;
+#endif
+  }
+
+  bool is_bound() const { return patch_site_.is_bound(); }
+
+ private:
+  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.  The actual
 // argument count matches the formal parameter count expected by the
 // function.
 //
 // The live registers are:
 //   o r1: the JS function object being called (ie, ourselves)
 //   o cp: our context
 //   o fp: our caller's frame pointer
 //   o sp: stack pointer
@@ skipping 687 matching lines @@
     Comment cmnt(masm_, "[ Case comparison");
     __ bind(&next_test);
     next_test.Unuse();
 
     // Compile the label expression.
     VisitForAccumulatorValue(clause->label());
 
     // Perform the comparison as if via '==='.
     __ ldr(r1, MemOperand(sp, 0));  // Switch value.
     bool inline_smi_code = ShouldInlineSmiCase(Token::EQ_STRICT);
+    JumpPatchSite patch_site(masm_);
     if (inline_smi_code) {
       Label slow_case;
       __ orr(r2, r1, r0);
-      __ tst(r2, Operand(kSmiTagMask));
-      __ b(ne, &slow_case);
+      patch_site.EmitJumpIfNotSmi(r2, &slow_case);
+
       __ cmp(r1, r0);
       __ b(ne, &next_test);
       __ Drop(1);  // Switch value is no longer needed.
       __ b(clause->body_target()->entry_label());
-    __ bind(&slow_case);
+      __ bind(&slow_case);
     }
 
-    CompareFlags flags = inline_smi_code
-        ? NO_SMI_COMPARE_IN_STUB
-        : NO_COMPARE_FLAGS;
-    CompareStub stub(eq, true, flags, r1, r0);
-    __ CallStub(&stub);
-    __ cmp(r0, Operand(0, RelocInfo::NONE));
+    // Record position before stub call for type feedback.
+    SetSourcePosition(clause->position());
+    Handle<Code> ic = CompareIC::GetUninitialized(Token::EQ_STRICT);
+    EmitCallIC(ic, &patch_site);
+
+    __ cmp(r0, Operand(0));
     __ b(ne, &next_test);
     __ Drop(1);  // Switch value is no longer needed.
     __ b(clause->body_target()->entry_label());
   }
 
   // Discard the test value and jump to the default if present, otherwise to
   // the end of the statement.
   __ bind(&next_test);
   __ Drop(1);  // Switch value is no longer needed.
   if (default_clause == NULL) {
@@ skipping 2720 matching lines @@
           cond = ge;
           __ pop(r1);
           break;
         case Token::IN:
         case Token::INSTANCEOF:
         default:
           UNREACHABLE();
       }
 
       bool inline_smi_code = ShouldInlineSmiCase(op);
+      JumpPatchSite patch_site(masm_);
       if (inline_smi_code) {
         Label slow_case;
         __ orr(r2, r0, Operand(r1));
-        __ JumpIfNotSmi(r2, &slow_case);
+        patch_site.EmitJumpIfNotSmi(r2, &slow_case);
         __ cmp(r1, r0);
         Split(cond, if_true, if_false, NULL);
         __ bind(&slow_case);
       }
-      CompareFlags flags = inline_smi_code
-          ? NO_SMI_COMPARE_IN_STUB
-          : NO_COMPARE_FLAGS;
-      CompareStub stub(cond, strict, flags, r1, r0);
-      __ CallStub(&stub);
+
+      // Record position and call the compare IC.
+      SetSourcePosition(expr->position());
+      Handle<Code> ic = CompareIC::GetUninitialized(op);
+      EmitCallIC(ic, &patch_site);
       PrepareForBailoutBeforeSplit(TOS_REG, true, if_true, if_false);
-      __ cmp(r0, Operand(0, RelocInfo::NONE));
+      __ cmp(r0, Operand(0));
       Split(cond, if_true, if_false, fall_through);
     }
   }
 
   // Convert the result of the comparison into one expected for this
   // expression's context.
   context()->Plug(if_true, if_false);
 }
 
 
@@ skipping 46 matching lines @@
 }
 
 
 void FullCodeGenerator::EmitCallIC(Handle<Code> ic, RelocInfo::Mode mode) {
   ASSERT(mode == RelocInfo::CODE_TARGET ||
          mode == RelocInfo::CODE_TARGET_CONTEXT);
   __ Call(ic, mode);
 }
 
 
+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);
   __ str(value, MemOperand(fp, frame_offset));
 }
 
 
 void FullCodeGenerator::LoadContextField(Register dst, int context_index) {
   __ ldr(dst, ContextOperand(cp, context_index));
 }
 
@@ skipping 24 matching lines @@
   __ mov(r1, Operand(r1, ASR, 1));  // Un-smi-tag value.
   __ add(pc, r1, Operand(masm_->CodeObject()));
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM