Fail early when re-entering code that has been patched for lazy deopt

R=ulan@chromium.org

Review URL: https://codereview.chromium.org/184373004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19607 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/a64/deoptimizer-a64.cc

@@ -50,6 +50,9 @@ void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) {
   // code patching below, and is not needed any more.
   code->InvalidateRelocation();
 
+  // TODO(jkummerow): if (FLAG_zap_code_space), make the code object's
+  // entry sequence unusable (see other architectures).
+
   // For each LLazyBailout instruction insert a call to the corresponding
   // deoptimization entry.
   DeoptimizationInputData* deopt_data =

src/arm/deoptimizer-arm.cc

@@ -50,6 +50,26 @@ void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) {
   // code patching below, and is not needed any more.
   code->InvalidateRelocation();
 
+  if (FLAG_zap_code_space) {
+    // Fail hard and early if we enter this code object again.
+    byte* pointer = code->FindCodeAgeSequence();
+    if (pointer != NULL) {
+      pointer += kNoCodeAgeSequenceLength;
+    } else {
+      pointer = code->instruction_start();
+    }
+    CodePatcher patcher(pointer, 1);
+    patcher.masm()->bkpt(0);
+
+    DeoptimizationInputData* data =
+        DeoptimizationInputData::cast(code->deoptimization_data());
+    int osr_offset = data->OsrPcOffset()->value();
+    if (osr_offset > 0) {
+      CodePatcher osr_patcher(code->instruction_start() + osr_offset, 1);
+      osr_patcher.masm()->bkpt(0);
+    }
+  }
+
   // For each LLazyBailout instruction insert a call to the corresponding
   // deoptimization entry.
   DeoptimizationInputData* deopt_data =

src/ia32/deoptimizer-ia32.cc

@@ -116,6 +116,27 @@ void Deoptimizer::EnsureRelocSpaceForLazyDeoptimization(Handle<Code> code) {
 
 void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) {
   Address code_start_address = code->instruction_start();
+
+  if (FLAG_zap_code_space) {
+    // Fail hard and early if we enter this code object again.
+    byte* pointer = code->FindCodeAgeSequence();
+    if (pointer != NULL) {
+      pointer += kNoCodeAgeSequenceLength;
+    } else {
+      pointer = code->instruction_start();
+    }
+    CodePatcher patcher(pointer, 1);
+    patcher.masm()->int3();
+
+    DeoptimizationInputData* data =
+        DeoptimizationInputData::cast(code->deoptimization_data());
+    int osr_offset = data->OsrPcOffset()->value();
+    if (osr_offset > 0) {
+      CodePatcher osr_patcher(code->instruction_start() + osr_offset, 1);
+      osr_patcher.masm()->int3();
+    }
+  }
+
   // We will overwrite the code's relocation info in-place. Relocation info
   // is written backward. The relocation info is the payload of a byte
   // array.  Later on we will slide this to the start of the byte array and

src/mips/deoptimizer-mips.cc

@@ -49,6 +49,26 @@ void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) {
   // code patching below, and is not needed any more.
   code->InvalidateRelocation();
 
+  if (FLAG_zap_code_space) {
+    // Fail hard and early if we enter this code object again.
+    byte* pointer = code->FindCodeAgeSequence();
+    if (pointer != NULL) {
+      pointer += kNoCodeAgeSequenceLength;
+    } else {
+      pointer = code->instruction_start();
+    }
+    CodePatcher patcher(pointer, 1);
+    patcher.masm()->break_(0xCC);
+
+    DeoptimizationInputData* data =
+        DeoptimizationInputData::cast(code->deoptimization_data());
+    int osr_offset = data->OsrPcOffset()->value();
+    if (osr_offset > 0) {
+      CodePatcher osr_patcher(code->instruction_start() + osr_offset, 1);
+      osr_patcher.masm()->break_(0xCC);
+    }
+  }
+
   // For each LLazyBailout instruction insert a call to the corresponding
   // deoptimization entry.
   DeoptimizationInputData* deopt_data =

src/objects.h

@@ -5627,6 +5627,7 @@ class Code: public HeapObject {
 
  private:
   friend class RelocIterator;
+  friend class Deoptimizer;  // For FindCodeAgeSequence.
 
   void ClearInlineCaches(Kind* kind);
 

src/x64/deoptimizer-x64.cc

@@ -51,6 +51,26 @@ void Deoptimizer::PatchCodeForDeoptimization(Isolate* isolate, Code* code) {
   // code patching below, and is not needed any more.
   code->InvalidateRelocation();
 
+  if (FLAG_zap_code_space) {
+    // Fail hard and early if we enter this code object again.
+    byte* pointer = code->FindCodeAgeSequence();
+    if (pointer != NULL) {
+      pointer += kNoCodeAgeSequenceLength;
+    } else {
+      pointer = code->instruction_start();
+    }
+    CodePatcher patcher(pointer, 1);
+    patcher.masm()->int3();
+
+    DeoptimizationInputData* data =
+        DeoptimizationInputData::cast(code->deoptimization_data());
+    int osr_offset = data->OsrPcOffset()->value();
+    if (osr_offset > 0) {
+      CodePatcher osr_patcher(code->instruction_start() + osr_offset, 1);
+      osr_patcher.masm()->int3();
+    }
+  }
+
   // For each LLazyBailout instruction insert a absolute call to the
   // corresponding deoptimization entry, or a short call to an absolute
   // jump if space is short. The absolute jumps are put in a table just