1331414: Adding javascript.options.jit.full_debug_checks in about:config for people that want to use debug builds for surfing with less slowdown

1331414: Adding javascript.options.jit.full_debug_checks in about:config for people that want to use debug builds for surfing with less slowdown

js/src/jit/CodeGenerator.cpp

@@ -5291,8 +5291,10 @@ CodeGenerator::generateBody()
                 extendTrackedOptimizationsEntry(iter->mirRaw()->trackedOptimizations());
 
 #ifdef DEBUG
-            if (!counts)
-                emitDebugResultChecks(*iter);
+            if (!counts) {
+                if (JitOptions.fullDebugChecks)
+                    emitDebugResultChecks(*iter);
+            }
 #endif
         }
         if (masm.oom())

js/src/jit/Ion.cpp

@@ -1833,6 +1833,7 @@ OptimizeMIR(MIRGenerator* mir)
         if (mir->shouldCancel("Make loops contiguous"))
             return false;
     }
+    AssertExtendedGraphCoherency(graph, /* underValueNumberer = */ false, /* force = */ true);
 
     // Passes after this point must not move instructions; these analyses
     // depend on knowing the final order in which instructions will execute.
@@ -1875,6 +1876,8 @@ OptimizeMIR(MIRGenerator* mir)
         gs.spewPass("Redundant Bounds Check Elimination");
         AssertGraphCoherency(graph);
     }
+    
+    AssertGraphCoherency(graph, /* force = */ true);
 
     DumpMIRExpressions(graph);
 
@@ -1919,8 +1922,10 @@ GenerateLIR(MIRGenerator* mir)
           case RegisterAllocator_Backtracking:
           case RegisterAllocator_Testbed: {
 #ifdef DEBUG
-            if (!integrity.record())
-                return nullptr;
+            if (JitOptions.fullDebugChecks) {
+                if (!integrity.record())
+                    return nullptr;
+            }
 #endif
 
             BacktrackingAllocator regalloc(mir, &lirgen, *lir,
@@ -1929,8 +1934,10 @@ GenerateLIR(MIRGenerator* mir)
                 return nullptr;
 
 #ifdef DEBUG
-            if (!integrity.check(false))
-                return nullptr;
+            if (JitOptions.fullDebugChecks) {
+                if (!integrity.check(false))
+                    return nullptr;
+            }
 #endif
 
             gs.spewPass("Allocate Registers [Backtracking]");

js/src/jit/IonAnalysis.cpp

@@ -2407,9 +2407,12 @@ AssertOperandsBeforeSafeInsertTop(MResumePoint* resume)
 #endif // DEBUG
 
 void
-jit::AssertBasicGraphCoherency(MIRGraph& graph)
+jit::AssertBasicGraphCoherency(MIRGraph& graph, bool force)
 {
 #ifdef DEBUG
+    if (!JitOptions.fullDebugChecks && !force)
+        return;
+
     MOZ_ASSERT(graph.entryBlock()->numPredecessors() == 0);
     MOZ_ASSERT(graph.entryBlock()->phisEmpty());
     MOZ_ASSERT(!graph.entryBlock()->unreachable());
@@ -2592,12 +2595,14 @@ AssertDominatorTree(MIRGraph& graph)
 #endif
 
 void
-jit::AssertGraphCoherency(MIRGraph& graph)
+jit::AssertGraphCoherency(MIRGraph& graph, bool force)
 {
 #ifdef DEBUG
     if (!JitOptions.checkGraphConsistency)
         return;
-    AssertBasicGraphCoherency(graph);
+    if (!JitOptions.fullDebugChecks && !force)
+        return;
+    AssertBasicGraphCoherency(graph, force);
     AssertReversePostorder(graph);
 #endif
 }
@@ -2682,7 +2687,7 @@ AssertResumePointDominatedByOperands(MResumePoint* resume)
 #endif // DEBUG
 
 void
-jit::AssertExtendedGraphCoherency(MIRGraph& graph, bool underValueNumberer)
+jit::AssertExtendedGraphCoherency(MIRGraph& graph, bool underValueNumberer, bool force)
 {
     // Checks the basic GraphCoherency but also other conditions that
     // do not hold immediately (such as the fact that critical edges
@@ -2691,8 +2696,10 @@ jit::AssertExtendedGraphCoherency(MIRGraph& graph, bool underValueNumberer)
 #ifdef DEBUG
     if (!JitOptions.checkGraphConsistency)
         return;
+    if (!JitOptions.fullDebugChecks && !force)
+        return;
 
-    AssertGraphCoherency(graph);
+    AssertGraphCoherency(graph, force);
 
     AssertDominatorTree(graph);
 

js/src/jit/IonAnalysis.h

@@ -78,13 +78,13 @@ MOZ_MUST_USE bool
 BuildPhiReverseMapping(MIRGraph& graph);
 
 void
-AssertBasicGraphCoherency(MIRGraph& graph);
+AssertBasicGraphCoherency(MIRGraph& graph, bool force = false);
 
 void
-AssertGraphCoherency(MIRGraph& graph);
+AssertGraphCoherency(MIRGraph& graph, bool force = false);
 
 void
-AssertExtendedGraphCoherency(MIRGraph& graph, bool underValueNumberer = false);
+AssertExtendedGraphCoherency(MIRGraph& graph, bool underValueNumberer = false, bool force = false);
 
 MOZ_MUST_USE bool
 EliminateRedundantChecks(MIRGraph& graph);

js/src/jit/JitOptions.cpp

@@ -160,6 +160,9 @@ DefaultJitOptions::DefaultJitOptions()
     // JSScript::hadFrequentBailouts and invalidate.
     SET_DEFAULT(frequentBailoutThreshold, 10);
 
+    // Whether to run all debug checks in debug builds.
+    // Disabling might make it more enjoyable to run JS in debug builds.
+    SET_DEFAULT(fullDebugChecks, true);
     // How many actual arguments are accepted on the C stack.
     SET_DEFAULT(maxStackArgs, 4096);
 

js/src/jit/JitOptions.h

@@ -66,6 +66,7 @@ struct DefaultJitOptions
     bool disableSink;
     bool eagerCompilation;
     bool forceInlineCaches;
+    bool fullDebugChecks;
     bool limitScriptSize;
     bool osr;
     bool asmJSAtomicsEnable;

js/src/jit/MIR.h

@@ -299,7 +299,7 @@ class MNode : public TempObject
 
   protected:
     // Need visibility on getUseFor to avoid O(n^2) complexity.
-    friend void AssertBasicGraphCoherency(MIRGraph& graph);
+    friend void AssertBasicGraphCoherency(MIRGraph& graph, bool force);
 
     // Gets the MUse corresponding to given operand.
     virtual MUse* getUseFor(size_t index) = 0;
@@ -11905,7 +11905,7 @@ class MResumePoint final :
 
   private:
     friend class MBasicBlock;
-    friend void AssertBasicGraphCoherency(MIRGraph& graph);
+    friend void AssertBasicGraphCoherency(MIRGraph& graph, bool force);
 
     // List of stack slots needed to reconstruct the frame corresponding to the
     // function which is compiled by IonBuilder.

js/src/jsapi.cpp

@@ -7119,6 +7119,11 @@ JS_SetGlobalJitCompilerOption(JSContext* cx, JSJitCompilerOption opt, uint32_t v
       case JSJITCOMPILER_ION_INLINING:
         jit::JitOptions.disableInlining = !value;
         break;
+#ifdef DEBUG
+      case JSJITCOMPILER_FULL_DEBUG_CHECKS:
+        jit::JitOptions.fullDebugChecks = !!value;
+        break;
+#endif
       default:
         break;
     }
@@ -7166,6 +7171,11 @@ JS_GetGlobalJitCompilerOption(JSContext* cx, JSJitCompilerOption opt, uint32_t*
       case JSJITCOMPILER_ION_INTERRUPT_WITHOUT_SIGNAL:
         *valueOut = jit::JitOptions.ionInterruptWithoutSignals ? 1 : 0;
         break;
+#ifdef DEBUG
+      case JSJITCOMPILER_FULL_DEBUG_CHECKS:
+        *valueOut = jit::JitOptions.fullDebugChecks ? 1 : 0;
+        break;
+#endif
       default:
         return false;
     }

js/src/jsapi.h

@@ -5316,7 +5316,8 @@ JS_SetOffthreadIonCompilationEnabled(JSContext* cx, bool enabled);
     Register(ION_INTERRUPT_WITHOUT_SIGNAL, "ion.interrupt-without-signals") \
     Register(ION_CHECK_RANGE_ANALYSIS, "ion.check-range-analysis")          \
     Register(BASELINE_ENABLE, "baseline.enable")                            \
-    Register(OFFTHREAD_COMPILATION_ENABLE, "offthread-compilation.enable")  \
+    Register(OFFTHREAD_COMPILATION_ENABLE, "offthread-compilation.enable")  \
+    Register(FULL_DEBUG_CHECKS, "jit.full-debug-checks")                    \
     Register(JUMP_THRESHOLD, "jump-threshold")                              \
     Register(UNBOXED_OBJECTS, "unboxed_objects")                            \
     Register(ASMJS_ATOMICS_ENABLE, "asmjs.atomics.enable")                  \

js/xpconnect/src/XPCJSContext.cpp

@@ -1492,7 +1492,10 @@ ReloadPrefsCallback(const char* pref, void* data)
     JS_SetGlobalJitCompilerOption(cx, JSJITCOMPILER_BASELINE_WARMUP_TRIGGER,
                                   baselineWarmUpThreshold);
     JS_SetGlobalJitCompilerOption(cx, JSJITCOMPILER_ION_WARMUP_TRIGGER,
-                                  ionWarmUpThreshold);
+                                  useIonEager ? 0 : ionThreshold);
+#ifdef DEBUG
+    JS_SetGlobalJitCompilerOption(cx, JSJITCOMPILER_FULL_DEBUG_CHECKS, fullJitDebugChecks);
+#endif
     JS_SetGlobalJitCompilerOption(cx, JSJITCOMPILER_UNBOXED_OBJECTS,
                                   unboxedObjects);
     JS_SetGlobalJitCompilerOption(cx, JSJITCOMPILER_ION_INLINING,

modules/libpref/init/all.js

@@ -1285,6 +1285,9 @@ pref("javascript.options.parallel_parsing", true);
 pref("javascript.options.asyncstack",       false);
 pref("javascript.options.throw_on_asmjs_validation_failure", false);
 pref("javascript.options.ion.offthread_compilation", true);
+#ifdef DEBUG
+pref("javascript.options.jit.full_debug_checks", true);
+#endif
 // This preference instructs the JS engine to discard the
 // source of any privileged JS after compilation. This saves
 // memory, but makes things like Function.prototype.toSource()