commit f0acfe7a812a332122011832074142718c278dae
author Nicolas Geoffray <ngeoffray@google.com> Mon Jan 09 20:54:52 2017 +0000
committer Nicolas Geoffray <ngeoffray@google.com> Tue Jan 10 21:26:23 2017 +0000
tree 49c4fc481cebd03323aaf0109066859165508303
parent 91db41f315f6c2366b7098c531224bee01170364

Keep resolved String in HLoadString.

For the following reasons:
- Avoids needing to do a lookup again in CodeGenerator::EmitJitRoots.
- Fixes races where we the string was GC'ed before CodeGenerator::EmitJitRoots.
- Makes it possible to do GVN on the same string but defined in different
  dex files.

Test: test-art-host, test-art-target
Change-Id: If2b5d3079f7555427b1b96ab04546b3373fcf921

compiler/optimizing/code_generator_arm_vixl.cc

diff --git a/compiler/optimizing/code_generator_arm_vixl.cc b/compiler/optimizing/code_generator_arm_vixl.cc
index 00ad3e3..b1f6d59 100644
--- a/compiler/optimizing/code_generator_arm_vixl.cc
+++ b/compiler/optimizing/code_generator_arm_vixl.cc
@@ -6022,7 +6022,9 @@
   }
 }
 
-void InstructionCodeGeneratorARMVIXL::VisitLoadString(HLoadString* load) {
+// NO_THREAD_SAFETY_ANALYSIS as we manipulate handles whose internal object we know does not
+// move.
+void InstructionCodeGeneratorARMVIXL::VisitLoadString(HLoadString* load) NO_THREAD_SAFETY_ANALYSIS {
   LocationSummary* locations = load->GetLocations();
   Location out_loc = locations->Out();
   vixl32::Register out = OutputRegister(load);
@@ -6042,8 +6044,9 @@
       return;  // No dex cache slow path.
     }
     case HLoadString::LoadKind::kBootImageAddress: {
-      DCHECK_NE(load->GetAddress(), 0u);
-      uint32_t address = dchecked_integral_cast<uint32_t>(load->GetAddress());
+      uint32_t address = dchecked_integral_cast<uint32_t>(
+          reinterpret_cast<uintptr_t>(load->GetString().Get()));
+      DCHECK_NE(address, 0u);
       __ Ldr(out, codegen_->DeduplicateBootImageAddressLiteral(address));
       return;  // No dex cache slow path.
     }
@@ -6063,7 +6066,8 @@
     }
     case HLoadString::LoadKind::kJitTableAddress: {
       __ Ldr(out, codegen_->DeduplicateJitStringLiteral(load->GetDexFile(),
-                                                        load->GetStringIndex()));
+                                                        load->GetStringIndex(),
+                                                        load->GetString()));
       // /* GcRoot<mirror::String> */ out = *out
       GenerateGcRootFieldLoad(load, out_loc, out, /* offset */ 0, kCompilerReadBarrierOption);
       return;
@@ -7444,9 +7448,12 @@
   return DeduplicateUint32Literal(address, &uint32_literals_);
 }
 
-VIXLUInt32Literal* CodeGeneratorARMVIXL::DeduplicateJitStringLiteral(const DexFile& dex_file,
-                                                       dex::StringIndex string_index) {
-  jit_string_roots_.Overwrite(StringReference(&dex_file, string_index), /* placeholder */ 0u);
+VIXLUInt32Literal* CodeGeneratorARMVIXL::DeduplicateJitStringLiteral(
+    const DexFile& dex_file,
+    dex::StringIndex string_index,
+    Handle<mirror::String> handle) {
+  jit_string_roots_.Overwrite(StringReference(&dex_file, string_index),
+                              reinterpret_cast64<uint64_t>(handle.GetReference()));
   return jit_string_patches_.GetOrCreate(
       StringReference(&dex_file, string_index),
       [this]() {