Add JIT

Currently disabled by default unless -Xjit is passed in.

The proposed JIT is a method JIT which works by utilizing interpreter
instrumentation to request compilation of hot methods async during
runtime.

JIT options:
-Xjit / -Xnojit
-Xjitcodecachesize:N
-Xjitthreshold:integervalue

The JIT has a shared copy of a compiler driver which is accessed
by worker threads to compile individual methods.

Added JIT code cache and data cache, currently sized at 2 MB
capacity by default. Most apps will only fill a small fraction of
this cache however.

Added support to the compiler for compiling interpreter quickened
byte codes.

Added test target ART_TEST_JIT=TRUE and --jit for run-test.

TODO:
Clean up code cache.
Delete compiled methods after they are added to code cache.
Add more optimizations related to runtime checks e.g. direct pointers
for invokes.
Add method recompilation.
Move instrumentation to DexFile to improve performance and reduce
memory usage.

Bug: 17950037

Change-Id: Ifa5b2684a2d5059ec5a5210733900aafa3c51bca
diff --git a/compiler/dex/mir_method_info.cc b/compiler/dex/mir_method_info.cc
index b234950..3d3d979 100644
--- a/compiler/dex/mir_method_info.cc
+++ b/compiler/dex/mir_method_info.cc
@@ -33,51 +33,103 @@
     DCHECK(method_infos != nullptr);
     DCHECK_NE(count, 0u);
     for (auto it = method_infos, end = method_infos + count; it != end; ++it) {
-      MirMethodLoweringInfo unresolved(it->MethodIndex(), it->GetInvokeType());
+      MirMethodLoweringInfo unresolved(it->MethodIndex(), it->GetInvokeType(), it->IsQuickened());
+      unresolved.declaring_dex_file_ = it->declaring_dex_file_;
+      unresolved.vtable_idx_ = it->vtable_idx_;
       if (it->target_dex_file_ != nullptr) {
         unresolved.target_dex_file_ = it->target_dex_file_;
         unresolved.target_method_idx_ = it->target_method_idx_;
       }
-      DCHECK_EQ(memcmp(&unresolved, &*it, sizeof(*it)), 0);
+      if (kIsDebugBuild) {
+        unresolved.CheckEquals(*it);
+      }
     }
   }
 
   // We're going to resolve methods and check access in a tight loop. It's better to hold
   // the lock and needed references once than re-acquiring them again and again.
   ScopedObjectAccess soa(Thread::Current());
-  StackHandleScope<3> hs(soa.Self());
+  StackHandleScope<4> hs(soa.Self());
   Handle<mirror::DexCache> dex_cache(hs.NewHandle(compiler_driver->GetDexCache(mUnit)));
   Handle<mirror::ClassLoader> class_loader(
       hs.NewHandle(compiler_driver->GetClassLoader(soa, mUnit)));
   Handle<mirror::Class> referrer_class(hs.NewHandle(
       compiler_driver->ResolveCompilingMethodsClass(soa, dex_cache, class_loader, mUnit)));
+  auto current_dex_cache(hs.NewHandle<mirror::DexCache>(nullptr));
   // Even if the referrer class is unresolved (i.e. we're compiling a method without class
   // definition) we still want to resolve methods and record all available info.
+  const DexFile* const dex_file = mUnit->GetDexFile();
+  const bool use_jit = Runtime::Current()->UseJit();
+  const VerifiedMethod* const verified_method = mUnit->GetVerifiedMethod();
 
   for (auto it = method_infos, end = method_infos + count; it != end; ++it) {
+    // For quickened invokes, the dex method idx is actually the mir offset.
+    if (it->IsQuickened()) {
+      const auto* dequicken_ref = verified_method->GetDequickenIndex(it->method_idx_);
+      CHECK(dequicken_ref != nullptr);
+      it->target_dex_file_ = dequicken_ref->dex_file;
+      it->target_method_idx_ = dequicken_ref->index;
+    }
     // Remember devirtualized invoke target and set the called method to the default.
     MethodReference devirt_ref(it->target_dex_file_, it->target_method_idx_);
     MethodReference* devirt_target = (it->target_dex_file_ != nullptr) ? &devirt_ref : nullptr;
-    it->target_dex_file_ = mUnit->GetDexFile();
-    it->target_method_idx_ = it->MethodIndex();
-
     InvokeType invoke_type = it->GetInvokeType();
-    mirror::ArtMethod* resolved_method =
-        compiler_driver->ResolveMethod(soa, dex_cache, class_loader, mUnit, it->MethodIndex(),
-                                       invoke_type);
+    mirror::ArtMethod* resolved_method = nullptr;
+    if (!it->IsQuickened()) {
+      it->target_dex_file_ = dex_file;
+      it->target_method_idx_ = it->MethodIndex();
+      current_dex_cache.Assign(dex_cache.Get());
+      resolved_method = compiler_driver->ResolveMethod(soa, dex_cache, class_loader, mUnit,
+                                                       it->MethodIndex(), invoke_type);
+    } else {
+      // The method index is actually the dex PC in this case.
+      // Calculate the proper dex file and target method idx.
+      CHECK(use_jit);
+      CHECK_EQ(invoke_type, kVirtual);
+      // Don't devirt if we are in a different dex file since we can't have direct invokes in
+      // another dex file unless we always put a direct / patch pointer.
+      devirt_target = nullptr;
+      current_dex_cache.Assign(
+          Runtime::Current()->GetClassLinker()->FindDexCache(*it->target_dex_file_));
+      CHECK(current_dex_cache.Get() != nullptr);
+      DexCompilationUnit cu(
+          mUnit->GetCompilationUnit(), mUnit->GetClassLoader(), mUnit->GetClassLinker(),
+          *it->target_dex_file_, nullptr /* code_item not used */, 0u /* class_def_idx not used */,
+          it->target_method_idx_, 0u /* access_flags not used */,
+          nullptr /* verified_method not used */);
+      resolved_method = compiler_driver->ResolveMethod(soa, current_dex_cache, class_loader, &cu,
+                                                       it->target_method_idx_, invoke_type, false);
+      if (resolved_method != nullptr) {
+        // Since this was a dequickened virtual, it is guaranteed to be resolved. However, it may be
+        // resolved to an interface method. If this is the case then change the invoke type to
+        // interface with the assumption that sharp_type will be kVirtual.
+        if (resolved_method->GetInvokeType() == kInterface) {
+          it->flags_ = (it->flags_ & ~(kInvokeTypeMask << kBitInvokeTypeBegin)) |
+              (static_cast<uint16_t>(kInterface) << kBitInvokeTypeBegin);
+        }
+      }
+    }
     if (UNLIKELY(resolved_method == nullptr)) {
       continue;
     }
     compiler_driver->GetResolvedMethodDexFileLocation(resolved_method,
         &it->declaring_dex_file_, &it->declaring_class_idx_, &it->declaring_method_idx_);
-    it->vtable_idx_ = compiler_driver->GetResolvedMethodVTableIndex(resolved_method, invoke_type);
+    if (!it->IsQuickened()) {
+      // For quickened invoke virtuals we may have desharpened to an interface method which
+      // wont give us the right method index, in this case blindly dispatch or else we can't
+      // compile the method. Converting the invoke to interface dispatch doesn't work since we
+      // have no way to get the dex method index for quickened invoke virtuals in the interface
+      // trampolines.
+      it->vtable_idx_ =
+          compiler_driver->GetResolvedMethodVTableIndex(resolved_method, invoke_type);
+    }
 
-    MethodReference target_method(mUnit->GetDexFile(), it->MethodIndex());
+    MethodReference target_method(it->target_dex_file_, it->target_method_idx_);
     int fast_path_flags = compiler_driver->IsFastInvoke(
-        soa, dex_cache, class_loader, mUnit, referrer_class.Get(), resolved_method, &invoke_type,
-        &target_method, devirt_target, &it->direct_code_, &it->direct_method_);
-    bool is_referrers_class = (referrer_class.Get() == resolved_method->GetDeclaringClass());
-    bool is_class_initialized =
+        soa, dex_cache, class_loader, mUnit, referrer_class.Get(), resolved_method,
+        &invoke_type, &target_method, devirt_target, &it->direct_code_, &it->direct_method_);
+    const bool is_referrers_class = referrer_class.Get() == resolved_method->GetDeclaringClass();
+    const bool is_class_initialized =
         compiler_driver->IsMethodsClassInitialized(referrer_class.Get(), resolved_method);
     uint16_t other_flags = it->flags_ &
         ~(kFlagFastPath | kFlagClassIsInitialized | (kInvokeTypeMask << kBitSharpTypeBegin));