Merge pull request #149 from tjhance/disable-rewriting

disable rewriting

src/asm_writing/icinfo.cpp

@@ -67,6 +67,10 @@ ICSlotRewrite::~ICSlotRewrite() {
     free(buf);
 }
 
+void ICSlotRewrite::abort() {
+    ic->failed = true;
+}
+
 void ICSlotRewrite::commit(uint64_t decision_path, CommitHook* hook) {
     bool still_valid = true;
     for (int i = 0; i < dependencies.size(); i++) {
@@ -187,7 +191,7 @@ ICInfo::ICInfo(void* start_addr, void* continue_addr, StackInfo stack_info, int
                assembler::GenericRegister return_register, TypeRecorder* type_recorder)
     : next_slot_to_try(0), stack_info(stack_info), num_slots(num_slots), slot_size(slot_size),
       calling_conv(calling_conv), live_outs(live_outs.begin(), live_outs.end()), return_register(return_register),
-      type_recorder(type_recorder), start_addr(start_addr), continue_addr(continue_addr) {
+      type_recorder(type_recorder), failed(false), start_addr(start_addr), continue_addr(continue_addr) {
     for (int i = 0; i < num_slots; i++) {
         slots.push_back(SlotInfo(this, i));
     }
@@ -281,4 +285,8 @@ void ICInfo::clear(ICSlotInfo* icentry) {
     // writer->endWithSlowpath();
     llvm::sys::Memory::InvalidateInstructionCache(start, getSlotSize());
 }
+
+bool ICInfo::shouldAttempt() {
+    return !failed;
+}
 }

src/asm_writing/icinfo.h

@@ -73,6 +73,7 @@ public:
 
     void addDependenceOn(ICInvalidator&);
     void commit(uint64_t decision_path, CommitHook* hook);
+    void abort();
 
     friend class ICInfo;
 };
@@ -100,6 +101,7 @@ private:
     const std::vector<int> live_outs;
     const assembler::GenericRegister return_register;
     TypeRecorder* const type_recorder;
+    bool failed;
 
     // for ICSlotRewrite:
     ICSlotInfo* pickEntryForRewrite(uint64_t decision_path, const char* debug_name);
@@ -120,6 +122,8 @@ public:
     ICSlotRewrite* startRewrite(const char* debug_name);
     void clear(ICSlotInfo* entry);
 
+    bool shouldAttempt();
+
     friend class ICSlotRewrite;
 };
 

src/asm_writing/rewriter.cpp

@@ -649,6 +649,7 @@ RewriterVarUsage Rewriter::call(bool can_call_into_python, void* func_addr, std:
 void Rewriter::abort() {
     assert(!finished);
     finished = true;
+    rewrite->abort();
 
     for (auto v : args) {
         v->decUse();
@@ -1009,7 +1010,7 @@ Rewriter* Rewriter::createRewriter(void* rtn_addr, int num_args, const char* deb
 
     static StatCounter rewriter_nopatch("rewriter_nopatch");
 
-    if (!ic) {
+    if (!ic || !ic->shouldAttempt()) {
         rewriter_nopatch.log();
         return NULL;
     }