Bug 1235868 - Change nonWritableJITCode to ifdefs. r=jandem

js/src/jit/ExecutableAllocator.cpp

@@ -340,27 +340,25 @@ ExecutableAllocator::addSizeOfCode(JS::CodeSizes* sizes) const
 void
 ExecutableAllocator::reprotectAll(ProtectionSetting protection)
 {
-    if (!nonWritableJitCode)
-        return;
-
+#ifdef NON_WRITABLE_JIT_CODE
     if (!m_pools.initialized())
         return;
 
     for (ExecPoolHashSet::Range r = m_pools.all(); !r.empty(); r.popFront())
         reprotectPool(rt_, r.front(), protection);
+#endif
 }
 
 /* static */ void
 ExecutableAllocator::reprotectPool(JSRuntime* rt, ExecutablePool* pool, ProtectionSetting protection)
 {
+#ifdef NON_WRITABLE_JIT_CODE
     // Don't race with reprotectAll called from the signal handler.
     MOZ_ASSERT(rt->jitRuntime()->preventBackedgePatching() || rt->handlingJitInterrupt());
 
-    if (!nonWritableJitCode)
-        return;
-
     char* start = pool->m_allocation.pages;
     reprotectRegion(start, pool->m_freePtr - start, protection);
+#endif
 }
 
 /* static */ void
@@ -407,5 +405,3 @@ ExecutableAllocator::poisonCode(JSRuntime* rt, JitPoisonRangeVector& ranges)
         pool->release();
     }
 }
-
-bool ExecutableAllocator::nonWritableJitCode = true;

js/src/jit/ExecutableAllocator.h

@@ -157,6 +157,8 @@ struct JitPoisonRange
 
 typedef Vector<JitPoisonRange, 0, SystemAllocPolicy> JitPoisonRangeVector;
 
+#define NON_WRITABLE_JIT_CODE 1
+
 class ExecutableAllocator
 {
 #ifdef XP_WIN
@@ -183,8 +185,6 @@ class ExecutableAllocator
 
     static void initStatic();
 
-    static bool nonWritableJitCode;
-
   private:
     static size_t pageSize;
     static size_t largeAllocSize;
@@ -206,14 +206,16 @@ class ExecutableAllocator
   public:
     static void makeWritable(void* start, size_t size)
     {
-        if (nonWritableJitCode)
-            reprotectRegion(start, size, Writable);
+#ifdef NON_WRITABLE_JIT_CODE
+        reprotectRegion(start, size, Writable);
+#endif
     }
 
     static void makeExecutable(void* start, size_t size)
     {
-        if (nonWritableJitCode)
-            reprotectRegion(start, size, Executable);
+#ifdef NON_WRITABLE_JIT_CODE
+        reprotectRegion(start, size, Executable);
+#endif
     }
 
     void makeAllWritable() {

js/src/jit/ExecutableAllocatorPosix.cpp

@@ -81,7 +81,7 @@ static const unsigned FLAGS_RX = PROT_READ | PROT_EXEC;
 void
 ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSetting setting)
 {
-    MOZ_ASSERT(nonWritableJitCode);
+    MOZ_ASSERT(NON_WRITABLE_JIT_CODE);
     MOZ_ASSERT(pageSize);
 
     // Calculate the start of the page containing this region,
@@ -101,8 +101,9 @@ ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSetting
 /* static */ unsigned
 ExecutableAllocator::initialProtectionFlags(ProtectionSetting protection)
 {
-    if (!nonWritableJitCode)
-        return FLAGS_RW | FLAGS_RX;
-
+#ifdef NON_WRITABLE_JIT_CODE
     return (protection == Writable) ? FLAGS_RW : FLAGS_RX;
+#else
+    return FLAGS_RW | FLAGS_RX;
+#endif
 }

js/src/jit/ExecutableAllocatorWin.cpp

@@ -242,7 +242,7 @@ ExecutableAllocator::systemRelease(const ExecutablePool::Allocation& alloc)
 void
 ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSetting setting)
 {
-    MOZ_ASSERT(nonWritableJitCode);
+    MOZ_ASSERT(NON_WRITABLE_JIT_CODE);
     MOZ_ASSERT(pageSize);
 
     // Calculate the start of the page containing this region,
@@ -265,8 +265,9 @@ ExecutableAllocator::reprotectRegion(void* start, size_t size, ProtectionSetting
 /* static */ unsigned
 ExecutableAllocator::initialProtectionFlags(ProtectionSetting protection)
 {
-    if (!nonWritableJitCode)
-        return PAGE_EXECUTE_READWRITE;
-
+#ifdef NON_WRITABLE_JIT_CODE
     return (protection == Writable) ? PAGE_READWRITE : PAGE_EXECUTE_READ;
+#else
+    return PAGE_EXECUTE_READWRITE;
+#endif
 }

js/src/jit/JitCompartment.h

@@ -526,9 +526,9 @@ void FinishInvalidation(FreeOp* fop, JSScript* script);
 const unsigned WINDOWS_BIG_FRAME_TOUCH_INCREMENT = 4096 - 1;
 #endif
 
-// If ExecutableAllocator::nonWritableJitCode is |true|, this class will ensure
-// JIT code is writable (has RW permissions) in its scope. If nonWritableJitCode
-// is |false|, it's a no-op.
+// If NON_WRITABLE_JIT_CODE is enabled, this class will ensure
+// JIT code is writable (has RW permissions) in its scope.
+// Otherwise it's a no-op.
 class MOZ_STACK_CLASS AutoWritableJitCode
 {
     // Backedge patching from the signal handler will change memory protection

js/src/shell/js.cpp

@@ -3781,11 +3781,13 @@ EscapeForShell(AutoCStringVector& argv)
 
 static Vector<const char*, 4, js::SystemAllocPolicy> sPropagatedFlags;
 
+#if defined(JS_CODEGEN_X86) || defined(JS_CODEGEN_X64)
 static bool
 PropagateFlagToNestedShells(const char* flag)
 {
     return sPropagatedFlags.append(flag);
 }
+#endif
 
 static bool
 NestedShell(JSContext* cx, unsigned argc, Value* vp)
@@ -6690,7 +6692,7 @@ main(int argc, char** argv, char** envp)
         || !op.addIntOption('\0', "baseline-warmup-threshold", "COUNT",
                             "Wait for COUNT calls or iterations before baseline-compiling "
                             "(default: 10)", -1)
-        || !op.addBoolOption('\0', "non-writable-jitcode", "Allocate JIT code as non-writable memory.")
+        || !op.addBoolOption('\0', "non-writable-jitcode", "(NOP for fuzzers) Allocate JIT code as non-writable memory.")
         || !op.addBoolOption('\0', "no-fpu", "Pretend CPU does not support floating-point operations "
                              "to test JIT codegen (no-op on platforms other than x86).")
         || !op.addBoolOption('\0', "no-sse3", "Pretend CPU does not support SSE3 instructions and above "
@@ -6769,11 +6771,6 @@ main(int argc, char** argv, char** envp)
     OOM_printAllocationCount = op.getBoolOption('O');
 #endif
 
-    if (op.getBoolOption("non-writable-jitcode")) {
-        js::jit::ExecutableAllocator::nonWritableJitCode = true;
-        PropagateFlagToNestedShells("--non-writable-jitcode");
-    }
-
 #ifdef JS_CODEGEN_X86
     if (op.getBoolOption("no-fpu"))
         js::jit::CPUInfo::SetFloatingPointDisabled();